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The purpose of this study was firstly to examine the sensitivity of heart rate (HR)‐based and subjective monitoring markers to intensified endurance training; and secondly, to investigate the validity of these markers to distinguish individuals in different fatigue states. A total of 24 recreational runners performed a 3‐week baseline period, a 2‐week overload period, and a 1‐week recovery period. Performance was assessed before and after each period with a 3000m running test. Recovery was monitored with daily orthostatic tests, nocturnal HR recordings, questionnaires, and exercise data. The participants were divided into subgroups (overreached/OR, n = 8; responders/RESP, n = 12) based on the changes in performance and subjective recovery. The responses to the second week of the overload period were compared between the subgroups. RESP improved their baseline 3000 m time (p < 0.001) after the overload period (−2.5 ± 1.0%), and the change differed (p < 0.001) from OR (0.6 ± 1.2%). The changes in nocturnal HR (OR 3.2 ± 3.1%; RESP −2.8 ± 3.7%, p = 0.002) and HR variability (OR −0.7 ± 1.8%; RESP 2.1 ± 1.6%, p = 0.011) differed between the subgroups. In addition, the decrease in subjective readiness to train (p = 0.009) and increase in soreness of the legs (p = 0.04) were greater in OR compared to RESP. Nocturnal HR, readiness to train, and exercise‐derived HR‐running power index had ≥85% positive and negative predictive values in the discrimination between OR and RESP individuals. In conclusion, exercise tolerance can vary substantially in recreational runners. The results supported the usefulness of nocturnal HR and subjective recovery assessments in recognizing fatigue states. Highlights: Tolerance to similarly increased training load varies in recreational runners. While some individuals respond positively, for others the same load may be excessive.Subjective markers, such as readiness to train and soreness of the legs, were the most sensitive markers to respond to increased training load, and the magnitude of these responses was greater in individuals with suspected overreaching.Resting or exercise heart rate (HR) did not respond as systematically as the subjective markers to the training load itself. However, the changes in nocturnal HR, nocturnal HRV, and HR‐running power index started to differ between the RESP and OR subgroups at an earlier stage of the overload period supporting their usefulness as indicators of the fatigue state. [ABSTRACT FROM AUTHOR]

Blood flow restriction (BFR) is increasingly being used to enhance aerobic performance in endurance athletes. This study examined physiological responses to BFR applied in recovery phases within a high‐intensity interval training (HIIT) session in trained cyclists. Eleven competitive road cyclists (mean ± SD, age: 28 ± 7 years, body mass: 69 ± 6 kg, peak oxygen uptake: 65 ± 9 mL · kg−1 · min−1) completed two randomised crossover conditions: HIIT with (BFR) and without (CON) BFR applied during recovery phases. HIIT consisted of six 30‐s cycling bouts at an intensity equivalent to 85% of maximal 30‐s power (523 ± 93 W), interspersed with 4.5‐min recovery. BFR (200 mmHg, 12 cm cuff width) was applied for 2‐min in the early recovery phase between each interval. Pulmonary gas exchange (V̇O2, V̇CO2, and V̇E), tissue oxygen saturation index (TSI), heart rate (HR), and serum vascular endothelial growth factor concentration (VEGF) were measured. Compared to CON, BFR increased V̇CO2 and V̇E during work bouts (both p < 0.05, dz < 0.5), but there was no effect on V̇O2, TSI, or HR (p > 0.05). In early recovery, BFR decreased TSI, V̇O2, V̇CO2, and V̇E (all p < 0.05, dz > 0.8) versus CON, with no change in HR (p > 0.05). In late recovery, when BFR was released, V̇O2, V̇CO2, V̇E, and HR increased, but TSI decreased versus CON (all p < 0.05, dz > 0.8). There was a greater increase in VEGF at 3‐h post‐exercise in BFR compared to CON (p < 0.05, dz > 0.8). Incorporating BFR into HIIT recovery phases altered physiological responses compared to exercise alone. Highlights: Blood flow restriction (BFR) during high‐intensity interval training recovery phases increased acute physiological perturbations and angiogenic markers compared to interval training alone.During the early recovery phases of high‐intensity interval cycling, BFR decreased muscle oxygenation, V̇O2, V̇CO2, and V̇E compared to CON condition with unrestricted recovery. [ABSTRACT FROM AUTHOR]

This study examined the relationships between the decision‐making performances of soccer referees and markers of physiological load. Following baseline measurements and habituation procedures, 13 national‐level male referees completed a novel Soccer Referee Simulation whilst simultaneously adjudicating on a series of video‐based decision‐making clips. The correctness of each decision was assessed in relation to the mean heart rate (HR), respiratory rate (RR), minute ventilation (VE), perceptions of breathlessness (RPE‐B) and local muscular (RPE‐M) exertion and running speeds recorded in the 10‐s and 60‐s preceding decisions. There was a significant association between decision‐making accuracy and the mean HR (p = 0.042; VC = 0.272) and RR (p = 0.024, VC = 0.239) in the 10‐s preceding decisions, with significantly more errors observed when HR ≥ 90% of HRmax (OR, 5.39) and RR ≥ 80% of RRpeak (OR, 3.34). Decision‐making accuracy was also significantly associated with the mean running speeds performed in the 10‐s (p = 0.003; VC = 0.320) and 60‐s (p = 0.016; VC = 0.253) preceding decisions, with workloads of ≥250 m·min−1 associated with an increased occurrence of decisional errors (OR, 3.84). Finally, there was a significant association between decision‐making accuracy and RPE‐B (p = 0.021; VC = 0.287), with a disproportionate number of errors occurring when RPE‐B was rated as "very strong" to "maximal" (OR, 7.19). Collectively, the current data offer novel insights into the detrimental effects that high workloads may have upon the decision‐making performances of soccer referees. Such information may be useful in designing combined physical and decision‐making training programmes that prepare soccer referees for the periods of match play that prove most problematic to their decision‐making. Highlights: Soccer referees exhibited an increased likelihood of making a decisional error when: (1) HR ≥ 90% of HRmax; (2) RR ≥ 80% of RRpeak; (3) RPE‐B was rated as "very strong" to "maximal" (75–100 au); and (4) running speeds ≥250 m·min−1 were performed in the 10‐s prior to a decision.In contrast, the accuracy of the referees' decisions was not related to mean measures of HR, RR, or V̇E obtained in the 60‐s preceding decisions.The relationship between the physiological and decision‐making aspects of refereeing performance therefore appears to be a transient one, whereby high internal and external loads experienced immediately prior to infringements may compromise the correctness of the decision.Such information may be used to guide the design and delivery of training programmes aimed at preparing soccer referees for the periods of match play that prove most problematic to their decision‐making. [ABSTRACT FROM AUTHOR]

This study assessed the effect of a commercial carbohydrate menthol drink on cycling time trial (TT) performance in hot and humid conditions compared with a carbohydrate only drink. Ten participants (5 women; V̇O2max: 52.3 ± 8.6 mL kg−1 min−1, Peak Power Output: 286 ± 56 W) completed a 40‐min cycling preload (50% V̇O2max) followed by a 15‐min self‐paced TT in hot (∼35°C) and humid (∼54%) conditions on two occasions (double blind, crossover design). Every 10‐min, 85 mL of carbohydrate (CHO; SIS GO Energy, 60 g h−1) or carbohydrate and menthol (CHO + MEN; SIS Turbo+ 60 g h−1, 0.01% menthol) was swilled (∼10‐s) and ingested. Rectal temperature (Trec) and heart rate (HR) were recorded throughout. Thermal sensation (TS), thermal comfort (TC) and rating of perceived exertion (RPE) were recorded every 5‐min. Taste and aftertaste were rated from very pleasant (+5) to very unpleasant (−5). TT performance (total work; kJ) was similar between CHO (153 kJ [95% CI: 129–177 kJ]) and CHO + MEN (151 kJ [128–178 kJ]). During preload exercise, Trec increased by ∼0.9°C and was similar at the end of the TT (∼38.20°C). Mean preload HR was ∼140 b min−1 in each condition and reached ∼177 b min−1 at the end of the TT. TC was rated as 'much too warm' and TS rated as 'very hot' in both conditions. Both conditions were 'extremely hard' (end point RPE ∼19). All participants preferred the taste and aftertaste of the CHO drink. The commercial carbohydrate menthol drink offered no additional ergogenic benefit compared to a carbohydrate only drink during cycling exercise performed in hot and humid conditions. Highlights: The addition of menthol to a carbohydrate drink had no effect on 15‐min time trial performance.The addition of menthol to a carbohydrate drink had no effect on thermal perceptual measures or physiological measures.Taste and aftertaste perceptions were favourable towards the carbohydrate drink compared to the carbohydrate‐menthol drink. [ABSTRACT FROM AUTHOR]

Extreme-intensity exercise is described by W′ext (analogous to J′ for isometric exercise) that is smaller than W′ of severe-intensity exercise (W′sev) in males. Sex differences in exercise tolerance appear to diminish at near-maximal exercise, however, there is evidence of greater contributions of peripheral fatigue (i.e. potentiated twitch force; Qpot) in males during extreme-intensity exercise. Therefore, the current study tested the hypotheses that J′ext would not be different between males and females, however, males would exhibit a greater reduction in neuromuscular function (i.e. maximal voluntary contraction, MVC; Qpot) following extreme-intensity exercise. Seven males and 7 females completed three severe- (Tlim: 2–4 min, S3; 5–8 min, S2; 9–15 min, S1) and three extreme-intensity (70, 80, 90%MVC) knee-extension bouts. MVC and Qpot relative to baseline were compared at task failure and at 150 s of recovery. J′ext was significantly less than J′sev in males (2.4 ± 1.2kJ vs 3.9 ± 1.3kJ; p = 0.03) and females (1.6 ± 0.8kJ vs 2.9 ± 1.7kJ; p = 0.05); however, there were no sex differences in J′ext or J′sev. MVC (%Baseline) was greater at task failure following extreme-intensity exercise (76.5 ± 20.0% vs 51.5 ± 11.5% in males, 75.7 ± 19.4% vs 66.7 ± 17.4% in females), but was not different at 150 s of recovery (95.7 ± 11.8% in males, 91.1 ± 14.2% in females). Reduction in Qpot, however, was greater in males (51.9 ± 16.3% vs 60.6 ± 15.5%) and was significantly correlated with J′ext (r2 = 0.90, p < 0.001). Although there were no differences in the magnitude of J′ext, differences in MVC and Qpot are evidence of sex-specific responses and highlight the importance of appropriately characterizing exercise intensity regarding exercise domains when comparing physiological responses in males and females. Highlights We have previously shown evidence that extreme-intensity dynamic exercise is described by W′ext in males and smaller than W′sev. We currently tested for potential sex differences in J′ext (isometric analogue to W′) and neuromuscular responses (i.e. maximal voluntary contraction, MVC; potentiated twitch force, Qpot) during extreme-intensity exercise. J′ext and extreme-intensity exercise tolerance was not different between males and females. The reduction in MVC was not different across extreme-intensity exercise across males and females, whereas the reduction in Qpot was greater in males following all extreme-intensity exercises, although not after exercise at 90%MVC. Together, although extreme-intensity exercise tolerance is not different, these data highlight differences in the contributing mechanisms of fatigue during severe- and extreme-intensity exercise between males and females. [ABSTRACT FROM AUTHOR]

This study examined whether muscle typology (muscle fibre type composition) is related to maximal strength and whether it can explain the high inter-individual variability in number of repetitions to failure during resistance training. Ninety-five resistance training novices (57 males) were assessed for their maximal isometric knee extension strength and muscle typology. Muscle typology was estimated by measuring carnosine in the soleus, gastrocnemius and/or vastus lateralis using proton magnetic resonance spectroscopy. Forty-four subjects (22 males) performed dynamic strength tests (1RM) and 3 sets of leg extensions and curls to failure (60%1RM) to determine the association between muscle typology and (total) number of repetitions. Twenty-one subjects performed additional biceps curls and triceps extensions (60%1RM) to assess influence of exercise, 23 subjects performed additional leg extensions and curls at 80% and 40%1RM to evaluate influence of training load. There was a weak but significant relationship between muscle typology and maximal isometric strength (r = 0.22, p = 0.03) favouring the fast typology individuals. Slow and fast typology individuals did not differ in upper arm and upper leg 1RM. Total number of repetitions was related to muscle typology at 80% (r = −0.42; p = 0.04) and 60% (p = −0.44; p = 0.003) but not at 40%1RM. Slow typology individuals performed more repetitions to failure at 60%1RM in the leg extension (p = 0.03), leg curl (p = 0.01) and biceps curl (p = 0.02). In conclusion, muscle typology has a small contribution to maximal isometric strength but not dynamic strength and partly determines the number of repetitions to failure during resistance training. This insight can help individualizing resistance training prescriptions. Having a fast muscle typology is positively associated with maximal isometric strength delivery in resistance training novices. The muscle typology seems to be a determining characteristic in the number of repetitions that can be performed during resistance training as slow typology individuals perform significantly more repetitions to failure compared to fast typology individuals. This study indicates the importance for coaches to shift from using traditional load-repetition tables and 1RM prediction equations to individualized 1RM testing and training volume prescriptions. [ABSTRACT FROM AUTHOR]

Previous studies have concluded that wide variance in changes in insulin sensitivity markers following exercise training demonstrates heterogeneity in individual trainability. However, these studies frequently don't account for technical, biological, and random within-subject measurement error. We used the standard deviation of individual responses (SDIR) to determine whether interindividual variability in trainability exists for fasting and postprandial insulin sensitivity outcomes following low-volume sprint interval training (SIT). We pooled data from 63 untrained participants who completed 6 weeks of SIT (n = 49; VO2max: 35 (7) mL⋅kg−1⋅min−1) or acted as no-intervention controls (n = 14; VO2max: 34 (6) mL⋅kg−1⋅min−1). Fasting and oral glucose tolerance test (OGTT)-derived measures of insulin sensitivity were measured pre- and post-intervention. SDIR values were positive and exceeded a small effect size threshold for changes in fasting glucose (SDIR = 0.27 [95%CI 0.07,0.38] mmol⋅L−1), 2-h OGTT glucose (SDIR = 0.89 [0.22,1.23] mmol⋅L−1), glucose area-under-the-curve (SDIR = 66.4 [−81.5,124.3] mmol⋅L−1⋅120min−1) and The Cederholm Index (SDIR = 7.2 [−16.0,19.0] mg⋅l2⋅mmol−1⋅mU−1⋅min−1), suggesting meaningful individual responses to SIT, whilst SDIR values were negative for fasting insulin, fasting insulin resistance and insulin AUC. For all variables, the 95% CIs were wide and/or crossed zero, highlighting uncertainty about the existence of true interindividual differences in exercise trainability. Only 2–22% of participants could be classified as responders or non-responders with more than 95% certainty. Our findings demonstrate it cannot be assumed that variation in changes in insulin sensitivity following SIT is attributable to inherent differences in trainability, and reiterate the importance of accounting for technical, biological, and random error when examining heterogeneity in health-related training adaptations. Highlights This study tested whether true interindividual variability exists for changes in insulin sensitivity and glyceamic control following 6-weeks of low volume sprint interval training (SIT). The high level of technical, biological, and random error associated with repeated measurements of insulin sensitivity and glycaemic control, means we can neither confidently conclude that there is evidence of true interindividual differences in the trainability of these outcomes following SIT, nor confidently identify responders or non-responders for such parameters. Researchers contrasting responders vs. non-responders for a given parameter, either to understand mechanisms of adaptation and/or develop physiological/genetic/epigenetic predictors of response, need to be aware that identification of responders and non-responders with sufficient certainty may not be achievable for parameters with a high level of technical, biological, and random error. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate a field-based approach to determine torque-cadence and power-cadence profiles in professional cyclists and establish if this field-based protocol can differentiate between varying rider specialisations. Twenty-four male professional athletes from a World Tour cycling team participated in this investigation (Height = 1.84 ± 0.05 m, Weight = 72.3 ± 5.6 kg, Age = 25 ± 4 y). All riders were subsequently categorised into the following groups: 1) General Classification (GC) group; 2) sprinter group; and 3) classics group. All participants completed a specific sprint protocol in the field which included 6 times 6s sprints with varying gearing, starting cadences, starting speeds and position (i.e. seated vs standing). Power-cadence and torque-cadence profiles were determined based on the sprint outputs. There was a significant main effect of rider specialisation on the measured (sprint) variables (P≤0.03). Body weight, maximum power outputs (1s, 10s and modelled) and maximum torque were highest in the sprinter group, followed by the classics group, followed by the GC group. The protocol was able to differentiate between different rider specialisations (i.e. GC, sprinters, classics). The proposed methodology can contribute to individualising training content in the short-duration domain. Highlights Commercially available power metres can be used to assess power-cadence and torque cadence relationships in the field Key differences are present for the modelled parameters between cyclists of different specialisations Profiling a cyclist's power-cadence and torque-cadence relationship provides greater insight into the physiological mechanisms behind maximal power production [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate acute performance and physiological responses to the manipulation of exercise-to-rest ratio (E:R) during repeated-sprint hypoxic training (RSH) in hot conditions. Twelve male team-sport players completed two experimental sessions at a simulated altitude of ∼3000 m (FIO2 0.144), air temperature of 40°C and relative humidity of 50%. Exercise involved either 3 × 5 × 10-s (E:R1:2) or 3 × 10 × 5-s (E:R1:4) maximal cycling sprints interspersed with active recoveries at 120W (20-s between sprints, 2.5 and 5-min between sets for E:R1:2 and E:R1:4 respectively). Sessions were matched for overall sprint and total session duration (47.5-min). Peak and mean power output, and total work were greater in E:R1:4 than E:R1:2 (p < 0.05). Peak core temperature was significantly higher in E:R1:4 than E:R1:2 (38.44 ± 0.33 vs. 38.20 ± 0.35°C, p = 0.028). Muscle deoxygenation magnitude during sprints was greater in E:R1:2 (28.2 ± 1.6 vs. 22.4 ± 4.6%, p < 0.001), while muscle reoxygenation did not differ between conditions (p > 0.05). These results indicate E:R1:4 increased mechanical power output and core temperature compared to E:R1:2. Both protocols had different effects on measures of muscle oxygenation, with E:R1:2 generating greater muscle oxygen extraction and E:R1:4 producing more muscle oxygenation flux, which are both important signals for peripheral adaptation. We conclude that the E:R manipulation during RSH in the heat might be used to target different physiological and performance outcomes, with these findings forming a strong base for future mechanistic investigation. Highlights During a typical repeated-sprint training session conducted in hot and hypoxic conditions, an exercise-to-rest ratio of 1:4 during sprint efforts displayed an increased mechanical power output compared to an exercise-to-rest ratio of 1:2. This represents a potentially useful increase in training stimulus. An exercise-to-rest ratio of 1:2 generated greater muscle oxygen extraction, while an exercise-to-rest ratio of 1:4 resulted in more muscle oxygenation flux and a higher core temperature, indicating key markers of environment-related physiological strain were varied between conditions. Exercise-to-rest ratio manipulation may be used to target different physiological and performance outcomes when prescribing repeated-sprint training in hot and hypoxic conditions. [ABSTRACT FROM AUTHOR]

Since the beginning of the SARS-CoV-2 pandemic, the community use of facemasks has been widely recommended. However, their use during exercise has raised safety concerns. Thus, we compared the physiological differences between exercising wearing a surgical (SM) or a double-layer-cotton (DLC) facemask and not wearing a mask (NM). Sixteen volunteers underwent 4 bouts of cycling-based exercise, which consisted of two different intensities: light-to-moderate and moderate-to-high. Facemasks were used as follows: bout-1 and 4: NM; bout-2: SM or DLC and bout-3: DLC or SM. Ventilatory, metabolic, pulmonary gas exchange (PGE) and perceptual variables were collected. At both exercise intensities compared to NM, both facemasks induced similar ventilatory adaptations, increasing inspiratory time and tidal volume and decreasing breathing frequency. Effect sizes (ES) were larger for DLC than for SM. At moderate-to-high, both facemasks reduced the minute ventilation, whereas at light-to-moderate, it was only seen with DLC. End tidal and mixed CO2 pressures, as well as the difference between them, increased with both facemasks. Again, ES was larger for DLC than SM. No relevant oxygen saturation drop was observed with both facemaks and exercise intensities. A small ES increament in VO2 and VCO2 were seen with both facemasks. Effort perception increased at moderate-to-high for both exercise intensities, buth larger EF were with DLC than SM. DLC increased facial temperature during both exercise intensities. In conclusion, ventilatory adjustments imposed during facemask exercise influenced PGE and metabolic and perceptual changes. Larger ES were mostly seen for DLC than SM. Abbreviations: Bf: Breathing frequency.; CPET: Cardiopulmonary exercise test.; CI: Confidence interval.; DLC: Double-layer cotton.; ETCO2: End tidal CO2 pressure.; ES: Effect size.; ΔET-PECO2: Difference between ETCO2 and PECO2.; FMMT: Facemask microclimate temperature.; HR: Heart rate.; IQR: Interquartile range.; NM: No mask.; PECO2: Mixed-expired CO2 pressure.; RER: Respiratory exchange ratio.; RPE: Rate of perceived effort.; SD: Standard deviation.; SM: Surgical Mask.; SpO2: Oxygen saturation.; STP: Subjective thermal perception.; Ti/TTOT: Duty cycle.; VE: Minute ventilation.; VCO2: Carbon dioxide output.; VO2: Oxygen uptake.; VT: Tidal volume.; VT: Ventilatory threshold. Highlights Facemasks affect the breathing pattern by changing the frequency and amplitude of pulmonary ventilation. The augmented ventilatory work increases VO2, VCO2, and RPE and promotes nonconcerning drops in SpO2 and CO2 retention. Increased inspiratory and expiratory pressure can account for the reduction in pulmonary physiological dead space. [ABSTRACT FROM AUTHOR]

Previous research has explored the demands of amateur boxing-specific activity; however, no holistic review of the acute responses to such activity currently exists. This paper aimed to provide a systematic review of the available literature on the acute physiological, endocrine, biochemical, and performance responses to amateur boxing-specific activity. Following a search of EBSCOhost, SPORTDiscus, PubMed and Google Scholar databases, 25 studies were identified as meeting the inclusion criteria for the review. The methodological quality of the included studies was assessed via a modified Downs and Black checklist. Random-effects meta-analysis of standardised mean differences (SMD) revealed large (SMD = 4.62) increases in pre-post blood lactate (BLa), cortisol (SMD = 1.33), myoglobin (Mb) (SMD = 1.43), aspartate transaminase (AST) (SMD = 1.37), and alanine aminotransferase (ALT) (SMD = 0.97), in addition to moderate increases in creatine kinase (CK) (SMD = 0.65). Small pre–post increases in counter-movement jump (CMJ) height (SMD = 0.33) were observed. Consistently greater pre–post alterations were observed in competitive bouts, followed by sparring, and less so in boxing-specific simulations. Considerable physiological, endocrine, and biochemical responses are elicited following amateur boxing. Interestingly, neuromuscular and task-specific performance may not deteriorate following boxing-specific activity. The findings of the review may assist in the designing and periodising of boxing-specific training, dependent on the desired physical adaptations, training phase, and recovery status of the amateur boxer. Highlights Amateur boxing elicits a considerable acute physiological, hormonal, and biochemical response. Such responses are typically greater in competitive bouts, followed by sparring, and less so in simulated activity. The considerable demands of amateur boxing-specific activity do not appear to negatively affect neuromuscular or task-specific performance. Amateur boxers may be conditioned to preserve performance despite the acute demands of the sport, or the lack of performance decrement may reflect the short duration of amateur boxing. [ABSTRACT FROM AUTHOR]

Purpose: To study the effect of inhaling a beta-agonist (salbutamol) compared to placebo on skiing and cycling performance in well-trained elite athletes. Methods: Three different exercise protocols were used, all with a cross-over double blind placebo-controlled design. Participants inhaled 800 µg salbutamol or a placebo prior to the test, which was repeated on a following day with the participants inhaling the other substance. Fifteen junior elite skiers performed four free-style high intensity sprints (1100 m/work time 3.5–4.5 min). Twelve elite cyclists carried out a short cycling protocol, starting with two 5 min submaximal workloads followed by a maximal intermittent performance test to exhaustion. Another 12 elite cyclists performed the maximal intermittent performance test to exhaustion after a 150 min long submaximal cycling protocol. Results: Group mean time for the ski sprints increased, with no difference between treatment groups. In the short cycling protocol time to exhaustion was 9.1% (95% CI 52–161) lower after inhaling salbutamol compared to placebo and in the long cycling protocol time to exhaustion was 9.1% (95% CI – 121–267) lower after inhaling salbutamol compared to placebo. Blood lactate, heart rate and ventilation increased during submaximal exercise with salbutamol compared to placebo in the short cycling protocol (p <.05). Conclusion: This study could not confirm any positive performance effects from inhaling 800 µg salbutamol compared to placebo in skiing and high-intensity intermittent cycling performance. Instead, time to exhaustion in the maximal intermittent performance test was lower in both cycling protocols. Highlights There was no difference in performance time between salbutamol and placebo treatment in real-life applicable repeated ski sprints. Time to exhaustion in the maximal intermittent performance test was 9.1% lower after inhaling salbutamol compared to placebo, both when performed after 10 and 150 min of submaximal cycling. [ABSTRACT FROM AUTHOR]

The present study aimed to test the hypothesis that changes in the dermal tissue dielectric constant (TDC) and biomechanical properties of the skin would be correlated with the indicators related to dehydration. Ten healthy adult men were enrolled in three trials: no fluid intake (DEH), ad libitum fluid intake (AL-HYD), and programmed fluid intake (P-HYD) after exercise in a randomised crossover design. The participants performed a pedalling exercise at 60% heart rate reserve until 2% body mass loss. At 120 min after exercise, an incremental exercise test was carried out. Aerobic capacity, body composition, TDC, biomechanical properties of the skin (pliability, viscoelasticity, and total recovery), and indicators related to dehydration in the serum and urine were measured before and 120 min after exercise. Higher values of the pliability and viscoelasticity, and lower value of the total recovery on the hand were demonstrated in the P-HYD trial compared to the DEH trial (all P < 0.05). Changes in the TDC were significantly correlated with changes in body mass, total body water, serum osmolarity, and hematocrit (all P < 0.05). Changes in the biomechanical properties of the hand were significantly correlated with changes in body mass, hematocrit, and urine specific gravity (all P < 0.05). The present study showed that the changes in skin characteristics correlated with the body water and dehydration-associated indicators in the serum and urine, thus suggesting that skin characteristics may be useful in the assessment of dehydration. Highlights This study was the first to investigate the effect of dehydration and rehydration on the TDC and biomechanical properties of the skin upon instrumental measure, and not manual testing. This study confirmed the decline in aerobic capacity by dehydration and immediate recovery with sufficient rehydration. Changes in the TDC and the biomechanical properties of the skin correlated with the body water and dehydration-associated indicators in the serum and urine. Skin characteristics may be useful in the assessment of dehydration. [ABSTRACT FROM AUTHOR]

The present study investigates the effect of an acute intake of caffeine on the diurnal variation of neuromuscular performance in resistance-trained women. A total of 15 resistance-trained women participated in the current triple-blind, placebo-controlled, crossover experimental study. We assessed neuromuscular performance (i.e. ballistic (countermovement jump [CMJ] height and bench press throw [BPT] peak velocity), maximal strength (squat and bench press [BP] one-repetition maximum [1RM]), and strength-endurance [average velocity of the set during squat and number of repetitions-to-failure in BP]) four times at within 7 days. The participants ingested an acute dose of caffeine (3 mg/kg) or a placebo at 9–11 am and/or 17–19 pm. CMJ height (P =.016) and BP peak velocity (P =.012) were higher in the afternoon than in the morning. Compared to placebo, caffeine intake increased CMJ height by 3.1% in the morning and 1.6% in the afternoon (P =.035), but it had no effect on BPT peak velocity (P =.381). Maximal strength and strength-endurance performances were not affected by the time-of-day or caffeine intake (all P >.3). No significant interaction (time-of-day x substance) was observed in any of the above-mentioned outcomes (all P >.1). In conclusion, an acute dose of caffeine in the morning was effective to restore CMJ performance to levels found in the afternoon, while this effect was not observed neither in BPTpeak velocity nor in lower- and upper-body maximal strength and strength-endurance performance. Moreover, lower- and upper-body ballistic performance were greater in the afternoon than in the morning in resistance-trained women, while the acute intake of caffeine was only effective to increase CMJ height. Highlights Ballistic performance is probably higher in the afternoon than in the morning in resistance-trained women. An acute intake of caffeine is effective to increase countermovement jump performance. The ingestion of an acute dose of caffeine in the morning restored countermovement jump performance to levels found in the afternoon. [ABSTRACT FROM AUTHOR]

The present study aims to investigate the acute performance and physiological responses, with specific reference to muscle oxygenation, to ambient air temperature manipulation during repeated-sprint training in hypoxia (RSH). Thirteen male team-sport players completed one familiarisation and three experimental sessions at a simulated altitude of ∼3000 m (FIO2 0.144). Air temperatures utilised across the three experimental sessions were: 20°C, 35°C and 40°C (all 50% relative humidity). Participants performed 3 × 5 × 10-s maximal cycle sprints, with 20-s passive recovery between sprints, and 5 min active recovery between sets. There were no differences between conditions for cycling peak power, mean power, and total work (p>0.05). Peak core temperature (Tc) was not different between conditions (38.11 ± 0.36°C). Vastus lateralis muscle deoxygenation during exercise and reoxygenation during recovery was of greater magnitude in 35°C and 40°C than 20°C (p<0.001 for all). There was no condition × time interaction for Tc, skin temperature, pulse oxygen saturation, heart rate, rating of perceived exertion and thermal sensation (P>0.05). Exercise-induced increases in blood lactate concentration were higher in 35°C and 40°C than 20°C (p=0.010 and p=0.001, respectively). Integrating ambient temperatures up to 40°C into a typical RSH session had no detrimental effect on performance. Additionally, the augmented muscle oxygenation changes experienced during exercise and recovery in temperatures ≥35°C may indicate that the potency of RSH training is increased with additional heat. However, alterations to the training session may be required to generate a sufficient rise in Tc for heat training purposes. Highlights Heat exposure (35-40°C) did not affect mechanical performance during a typical RSH session. This indicates hot ambient temperature can be implemented during RSH, without negative consequence to training output. Hotter ambient conditions (35-40°C) likely result in greater muscle oxygenation changes during both exercise and recovery compared to temperate conditions. Although hotter sessions were perceived as more difficult and more thermally challenging, they did not further elevate Tc beyond that of temperate conditions. Accordingly, if intended to be used for heat acclimation purposes, alterations to the session may be required to increase heat load. [ABSTRACT FROM AUTHOR]

A low-frequency to a high-frequency component ratio (LF/HF) in heart rate variability (HRV) may not accurately reflect sympathetic nervous activity during exercise. Thus, a valid HRV-based index of sympathetic nervous activity is needed. Therefore, the heart rate to LF ratio (Heart rate/LF) was evaluated as sympathetic nervous activity index which is reflected by catecholamine levels during incremental exercise. In this study, 15 healthy adults performed an incremental exercise test using a cycle ergometer. HRV was derived from electrocardiography and HRV components related to the autonomic nervous system were obtained using frequency analysis. Heart rate/LF was calculated using the heart rate and LF component produced by HRV analysis. Catecholamine, blood lactate levels and respiratory gas were also measured throughout the exercise test. While LF/HF did not increase with increasing exercise intensity, Heart rate/LF non-linearly increased during the incremental exercise test, as did noradrenaline and blood lactate. Interestingly, Heart rate/LF values were positively correlated with noradrenaline (ρ = 0.788, p < 0.05) and blood lactate (ρ = 0.802, p < 0.05) levels and carbon dioxide production (ρ = 0.903, p < 0.05) from at rest through the exercise stages. Heart rate/LF reflects sympathetic nervous activity and metabolic responses during incremental cycling exercise and has potential as an HRV index of sympathetic nervous activity during exercise. Trial registration: UMIN Japan identifier: UMIN000039639. [ABSTRACT FROM AUTHOR]

Sex steroids, commonly referred to as sex hormones, are integral to the development and maintenance of the human reproductive system. In addition, male (androgens) and female (estrogens and progestogens) sex hormones promote the development of secondary sex characteristics by targeting a range of other tissues, including skeletal muscle. The role of androgens on skeletal muscle mass, function and metabolism has been well described in males, yet female specific studies are scarce in the literature. This narrative review summarises the available evidence around the mechanistic role of androgens, estrogens and progestogens in female skeletal muscle. An analysis of the literature indicates that sex steroids play important roles in the regulation of female skeletal muscle mass and function. The free fractions of testosterone and progesterone in serum were consistently associated with the regulation of muscle mass, while estrogens may be primarily involved in mediating the muscle contractile function in conjunction with other sex hormones. Muscle strength was however not directly associated with any hormone in isolation when at physiological concentrations. Importantly, recent evidence suggests that intramuscular sex hormone concentrations may be more strongly associated with muscle size and function than circulating forms, providing interesting opportunities for future research. By combining cross-sectional, interventional and mechanical studies, this review aims to provide a broad, multidisciplinary picture of the current knowledge of the effects of sex steroids on skeletal muscle in females, with a focus on the regulation of muscle size and function and an insight into their clinical implications. Free testosterone, but not total testosterone, is associated with lean mass but not strength in pre- and post-menopausal females. Progesterone and estrogens may regulate muscle mass and strength, respectively, in females. Intra-muscular steroids may be more closely associated to muscle mass and strength, compared to systemic fractions. [ABSTRACT FROM AUTHOR]

Despite the growing evidence for the beneficial effects of high-intensity interval exercise (HIIE) on vascular health of overweight and obese individuals, it is not clear whether the autonomic stress promoted by HIIE during the ambulatory period is higher than that by moderate-intensity continuous exercise (MICE). Therefore, this study compares the 24 hour (h) ambulatory heart rate variability (HRV) following HIIE and MICE in young overweight and obese men. Eleven untrained men aged 23.2 ± 1.9 years, with average body mass index (BMI) of 31.6 ± 3.9 kg/m² (three overweight and eight obese), underwent three exercise sessions: HIIE, MICE and Control (CT). HRV was recorded in the laboratory and for the next 24 h following laboratory recovery. There were no differences in HRV indices in the rest period between the sessions (p >.05). During the ambulatory period, the area under the curve (AUC) of the low-frequency band transformed into natural logarithm (Ln-LF) during sleep was higher after HIIE than after CT (43.31 ± 8.59 vs. 41.11 ± 7.28 ms²*h, p =.034). The HRV followed by MICE did not differ from other sessions (p >.05). In conclusion, the 24 h ambulatory HRV did not differ after HIIE and MICE. However, despite the small effect, HIIE increased the cardiac autonomic modulation during the sleep period, as a protector of cardiovascular system. 24 h ambulatory HRV could add important information about the cardiovascular safety of the exercise protocols in overweight and obese individuals. There was no disturbances in the cardiac autonomic modulation during the awake period, regardless of the exercise protocol. LnLF index was higher in HIIE compared to CT in the sleep period. 24 h ambulatory HRV did not differ between the HIIE and MICE sessions. [ABSTRACT FROM AUTHOR]

As with much of science, the female athlete is under researched, particularly in the area of gastrointestinal (GI) physiology. Gut function is of pivotal importance to athletes in that it supports digestion and absorption of nutrients, as well as providing a barrier between the external environment and the circulation. While sex-derived differences in GI structure and function have been well characterised at rest, there remains a paucity of data examining this during exercise. The wider impact of the GI system has begun to be realised and it is now widely acknowledged to play a role in more systemic bodily systems. In the current review, we discuss localised issues including the GI structure, function, and microbiome of male and females. We also discuss GI-related symptoms experienced by athletes, highlight the differences in incidence between males and females, and discuss contributing factors. We then move beyond the gut to discuss wider biological processes that have been shown to have both sex-related differences and that are impacted by the GI system. Some of these areas include immune function and risk of illness, sleep, hormones, bone health and the gut–brain–axis. The magnitude of such effects and relationships is currently unknown but there is enough mechanistic data for future studies to consider a more central role that the gastrointestinal tract may play in overall female athlete health. There are both clear similarities and differences in male-female gastrointestinal structure and function. Females typically reported a greater prevalence of gastrointestinal symptoms at rest, in particular during menstruation, but not during exercise. The links between female microbiome, oestrogen, and systemic physiological and biological processes are yet to be fully elucidated. Many of the male-female differences seen (e.g. in immune function) may be, at least in part, influenced by such GI related differences. [ABSTRACT FROM AUTHOR]

The aim of the present study was to test the effect of carbohydrate ingestion, simulating a 10-km open water race competition on energy cost (Csw), perceived exertion (RPE), heart rate (HR), stroke rate (SR) and performance. We hypothesized that carbohydrate ingestion would reduce Csw and RPE in elite open water swimmers (OW-swimmers) and improve performance. Eight elite OW-swimmers swam for 3 × 30 min with 20-s of interval necessary to collect data in the swimming flume at a pre-set pace corresponding to their 10-km race pace, followed by a time to exhaustion test (TTE) at 100% of the peak oxygen uptake (V̇O2peak). During the set, OW-swimmers ingested 45-g of carbohydrates (CHO) in 550-mL of water (8% solution) during each of the two intervals or a placebo solution (PLA). HR, RPE, V̇O2 and SR were measured. Shapiro–Wilk test was used to verify the normal distribution of data. Two-way repeated measures ANOVA and t-test was performed (p < 0.05). A significant difference emerged in TTE between the trials (169.00 ± 91.06 s in CHO; 102.31 ± 57.47 s in PLA). HR, RPE and SR increased during the TTE but did not differ between trials. Csw did not show a significant main effect between the two conditions and in time course in both conditions. CHO ingestion significantly increased TTE at 100% of V̇O2peak after 90-min of swimming at 10-km race pace. These findings indicate that CHO intake during a 10-km open water swimming competition should have a beneficial impact on performance in the final part of the race. [ABSTRACT FROM AUTHOR]

In 2013, the International Boxing Association (AIBA) prohibited the use of headguards for elite male Olympic boxing competitions. Could the removal of the headguard from elite male boxing competitions potentially cause increased injury risk for boxers? The aim of the literature review is to analyse current knowledge about the use of protective headgear and injury prevention in boxing, in order to determine if there are increased injury risks associated with headguard use. Peer-reviewed studies (language: English, Norwegian, Swedish, Danish and Dutch) published from 1980 and onwards were considered. Five academic databases and grey literature sources were searched, and articles were assessed for methodological quality. Only studies that included boxers as the study population with headguards as a factor were considered. A total of 39 articles were included in the review. The analysis of the reviewed literature indicates that headguards protect well against lacerations and skull fractures, while less is known about the protective effects against concussion and other traumatic brain injuries. Most of the analysed studies however use indirect evidence, obtained through self-report or observational techniques with relatively small non-representative samples. There are almost no randomised control trials, longitudinal research designs or samples from recreational boxing. Therefore, AIBA's decision to remove the headguard has to be seen with caution and injury rates among (male) boxers should be continuously evaluated. Highlights Research does not sufficiently support the statement that boxing without protective headgear is safer than boxing with a headguard. Headguards protect well against facial cuts and skull fractures. The systematic review indicates that headguards provide some protection against linear impacts to the head. The headguards protective effects against concussion are however uncertain. A research agenda is proposed. Priority areas include a focus on longitudinal research designs, randomized control trials, samples from recreational competitive boxing, as well as further research into coaches' and athletes' experiences and perspectives on headguards and injuries. [ABSTRACT FROM AUTHOR]

This study evaluated the contribution of physiological data collected during laboratory testing in predicting race performances of trained junior middle-distance track (TK) and cross-country (XC) athletes. Participants performed a submaximal incremental ramp test, followed by an incremental test to exhaustion in a laboratory, with the results used to predict either 800 m TK, 1500 m TK or 4000–6000 m XC race performance. Twenty-eight participants (male (M), 15; female (F), 13) were analysed (age = 17 ± 2 years, height = 1.72 ± 0.08 m, body mass = 58.9 ± 8.9 kg). Performance times (min:s) for 800 m were: M, 1:56.55 ± 0:05.55 and F, 2:14.21 ± 0:03.89; 1500 m: M, 3:51.98 ± 0:07.35 and F 4:36.71 ± 0:16.58; XC: M (4900 ± 741 m), 16:00 ± 01:53; F (4628 ± 670 m), 17:41 ± 02:09. Stepwise regression analysis indicated significant contributions of speed at ⩒O2max (s⩒O2max), and heart rate maximum (HRmax) to the prediction of 800 m TK (F(2,15) = 22.51, p < 0.001, adjusted R2 = 0.72), s⩒O2max for 1500 m TK (F(1,13) = 36.65, p < 0.001, adjusted R2 = 0.72) and ⩒O2max, allometrically scaled to body mass and speed at lactate threshold (sLT) for XC (F(2,17) = 25.1, p < 0.001, adjusted R2 = 0.72). Laboratory-based physiological measures can explain 72% of the variance in junior TK and XC events, although factors that explain performance alter depending on the race distance and tactics. The factors determining performance in TK and XC events are not interchangeable. [ABSTRACT FROM AUTHOR]

Military personnel are required to complete physically demanding tasks when performing work and training, which may be quantified through the physical stress imposed (external load) or the resultant physiological strain (internal load). The aim of this narrative review is to provide an overview of the techniques used to monitor work and training load in military settings, summarise key findings, and discuss important practical, analytical, and conceptual considerations. Most investigations have focused upon measuring external and internal load in military training environments; however, limited data exist in operational settings. Accelerometry has been the primary tool used to estimate external load, with heart rate commonly used to quantify internal load. Supplemental to heart rate, psychophysiological and biochemical measures have also been investigated to elucidate aspects of internal load. Broadly, investigations have revealed that military training requires personnel to perform relatively large volumes of physical activity (e.g. averaging ∼15,000 steps·day−1) of typically low-moderate intensity activity (<6 MET), although considerable temporal and inter-individual variability is observed from these gross mean estimates. There are limitations associated with these measures and, at best, estimates of external and internal load can only be inferred. These limitations are particularly pertinent for military tasks such as load carriage and manual material handling, which often involve complex activities performed individually or in teams, in a range of operational environments, with multiple layers of protection, over a protracted duration. Comprehensively quantifying external and internal loads during these functional activities poses substantial practical and analytical challenges. [ABSTRACT FROM AUTHOR]

Most of the low energy availability (LEA) research has been conducted in female populations. The occurrence of LEA in male athletes is not well known, even with an understanding of the components involved in and contributing to LEA. Cycling is a major risk factor for LEA due to inherent sports characteristics: low impact, high energy demands, and a common perception that leanness is a performance advantage. The purpose of this review is to discuss the cycling-specific studies that have documented components of RED-S. The review demonstrates male cyclists (1) experience energy deficits daily, weekly and throughout a season; (2) exhibit lower bone mineral density at the spine compared to the hip, and low bone mineral density correlating with LEA and; (3) demonstrate downregulation of the endocrine system with elevated cortisol, reduced testosterone and insulin-like growth factor 1. The complexity of LEA is further explored by the socio-psychological contribution that may impact eating behaviours, and therefore increase the risk of developing LEA. Future research directions include applying multifaceted research methods to gain a greater understanding of this syndrome and the effect of LEA on male cyclists. [ABSTRACT FROM AUTHOR]

Omission of a carbohydrate-rich breakfast followed by consuming an ad libitum lunch impairs evening exercise performance. However, it is unclear if this is due to breakfast omission per se, or secondary to lower carbohydrate intake over the day. To test whether impaired evening performance following breakfast omission persists when complete dietary compensation occurs at lunch, in a randomised cross-over design, eleven highly trained cyclists (age: 25 ± 7 y, VO2max: 61 ± 5 ml·kg−1·min−1) completed two trials: breakfast (B) and no breakfast (NB). During B, participants consumed an individualised breakfast (583 ± 54 kcal; 8–9am) and lunch (874 ± 80 kcal; 12–2pm), whilst during NB participants fasted until 12pm and then consumed a standardised lunch (1457 ± 134 kcal: 12–2pm). The overall energy (1457 ± 134 kcal) and macronutrient profile (carbohydrate: 81.5 ± 0.4%, fat: 5.8 ± 0.1%, protein: 12.7 ± 0.3%) was identical in both trials, with timing the only difference. Mean power output during a 20 km time trial performed in the evening was ~3% lower in NB compared to B (mean difference [95% CI]: −9.1 [−15.3, −2.9] watts, p < 0.01 for condition main effect). No differences in heart rate, blood glucose or blood lactate concentrations were apparent, but perception of effort appeared to be higher in the early stages of the time trial in NB compared to B despite lower power output. Impaired high-intensity endurance performance in the evening following breakfast omission is related to meal timing rather than carbohydrate intake / availability. Provision of an early morning high-carbohydrate meal should be considered to optimise evening exercise performance. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess lactate kinetics, maximal lactate accumulation rate (⩒Lamax) and peak power output (POmax) in a 15-s all-out exercise in handcycling (HC) and cycling (C) in terms of (1) reliability, (2) differences and (3) correlations between HC and C. Eighteen female and male competitive triathletes performed two trials (separated by one week) of a 15-s all-out sprint test in HC and C. Tests were performed in a recumbent racing handcycle and on the participants' own road bike that were attached to an ergometer. Reliability was assessed using intraclass correlation coefficient (ICC). POmax and ⩒Lamax demonstrated high reliability in HC (ICC = 0.972, ICC = 0.828) and C (ICC = 0.937, ICC = 0.872). POmax (d = −2.54, P < 0.0005) and ⩒Lamax (d = −1.62, P < 0.0005) were lower in HC compared to C. POmax and ⩒Lamax correlated in HC (r = 0.729, P = 0.001) and C (r = 0.710, P = 0.001). There was no significant correlation between HC and C in POmax (r = 0.442, P = 0.066) and ⩒Lamax (r = 0.455, P = 0.058). Whereas the exchange velocity of lactate (k1) was similar in HC and C, the removal velocity (k2) was significantly higher in HC. ⩒Lamax and POmax during sprint exercise are highly reliable and demonstrate a correlation in both HC and C. However, since ⩒Lamax and POmax are significantly higher in C and not correlated between HC and C, ⩒Lamax and POmax seem to be extremity-specific. [ABSTRACT FROM AUTHOR]

Training prescription in running activities have benefited from power output (PW) data obtained by new technologies. Nevertheless, to date, the suitability of PW data provided by these tools is still uncertain. The present study aimed to: (i) analyze the repeatability of five commercially available technologies for running PW estimation, and (ii) examine the concurrent validity through the relationship between each technology PW and oxygen uptake (VO2). On two occasions (test-retest), twelve endurance-trained male athletes performed on a treadmill (indoor) and an athletic track (outdoor) three submaximal running protocols with manipulations in speed, body weight and slope. PW was simultaneously registered by the commercial technologies StrydApp, StrydWatch, RunScribe, GarminRP and PolarV, while VO2 was monitored by a metabolic cart. Test-retest data from the environments (indoor and outdoor) and conditions (speed, body weight and slope) were used for repeatability analysis, which included the standard error of measurement (SEM), coefficient of variation (CV) and intraclass correlation coefficient (ICC). A linear regression analysis and the standard error of estimate (SEE) were used to examine the relationship between PW and VO2. Stryd device was found as the most repeatable technology for all environments and conditions (SEM ≤ 12.5 W, CV ≤ 4.3%, ICC ≥ 0.980), besides the best concurrent validity to the VO2 (r ≥ 0.911, SEE ≤ 7.3%). On the contrary, although the PolarV, GarminRP and RunScribe technologies maintain a certain relationship with VO2, their low repeatability questions their suitability. The Stryd can be considered as the most recommended tool, among the analyzed, for PW measurement. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the correlations between players' mechanical capacities determined during off- and on-ice tests. Whole body force-velocity relationships were assessed in elite female ice hockey players (n = 17) during jumping [squat jump (SJ)], running (5 and 30 m) and skating (5 and 40 m) sprint tasks. Mechanical capacities estimates include relative maximal theoretical force (F0rel), velocity (V0), power (Pmaxrel), slope of the linear relationship between force relative to body mass and velocity (SFVrel), maximal horizontal component of the ground reaction force to the corresponding resultant force (RFmax) and minimal rate of decrease of this ratio (DRF). On-ice mechanical capacities (F0rel, Pmaxrel, RFmax and DRF) largely-to-very largely correlated with 40-m skating split time (r ranging from 0.82 for DRF to −0.91 for Pmaxrel; p < 0.001). Performance variables (SJ height, 30-m running and 40-m forward skating split time) and Pmaxrel demonstrated the largest associations between jumping, running and skating tasks (r ranging from −0.81 for 30-m sprint running time to 0.92 for SJ height; p < 0.001). Small (V0, SFVrel, DRF and force-velocity deficit) to very large (Pmaxrel) correlations (r ranging from 0.58 to 0.72; p < 0.05) were obtained between mechanical variables inferred from off- and on-ice force-velocity tests. The capacity to generate high amounts of horizontal power and effective horizontal force during the first steps on the ice is paramount for forward skating sprint performance. Mechanical capacities determined during forward skating sprint could be considered in ice hockey testing to identify fitness and/or technical/training requirements. [ABSTRACT FROM AUTHOR]

Rugby League is a team sport requiring players to experience large impact collisions, thus requiring high amounts of muscle mass. Many players (academy and senior) strive to increase muscle mass during the pre-season, however, quantification of changes during this period have not been thoroughly investigated. We therefore assessed changes in body-composition using Dual X-Ray Absorptiometry (DXA) in eleven academy players over three successive pre-seasons and ninety-three senior players from four different European Super League clubs prior to, and at the end of, a pre-season training period. There was no meaningful change in lean mass of the academy players during any of the pre-season periods (year 1 = 72.3 ± 7.1–73.2 ± 7.2kg; ES 0.05, year 2 = 74.4 ± 6.9–75.5 ± 6.9kg; ES 0.07, year 3 = 75.9 ± 6.7–76.8 ± 6.6kg; ES 0.06) with small changes only occurring over the three-year study period (72.3–75.9kg; ES = 0.22). Senior players showed trivial changes in all characteristics during the pre-season period (total mass = 95.1–95.0kg; ES −0.01, lean mass = 74.6–75.1kg; ES 0.07, fat mass = 13.6–12.9kg; ES −0.17, body fat percentage = 14.8–14.1%; ES −0.19). These data suggest that academy players need time to develop towards profiles congruent with senior players. Moreover, once players reach senior level, body-composition changes are trivial during the pre-season and therefore teams may need to individualise training for players striving to gain muscle mass by reducing other training loads. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the vascular responses to acute free-weight (FW) resistance exercise (RE) versus weight machines (WM). Thirty-two resistance-trained individuals participated in this study. Both modalities involved performing acute RE and a control. Blood pressure and measures of pulse wave reflection were assessed using pulse wave analysis. Aortic stiffness was assessed using carotid–femoral pulse wave velocity (cf-PWV). A repeated measures analysis of variance was used to determine the effects of modality (FW and WM) and condition (acute RE and control) across time (rest and 10-20 min after exercise) on measures of pulse wave reflection and aortic stiffness. Significance was set a priori at p ≤ 0.05. There were no modality by condition by time interactions for any variable, such that the FW and WM modalities responded similarly across time after acute RE (p > 0.05). There were significant (p ≤ 0.05) increases in heart rate, aortic systolic blood pressure, aortic pulse pressure, augmentation index normalized at 75bpm, and decreases in subendocardial viability ratio (SEVR) after acute RE, compared to rest. There was also a significant (p ≤ 0.05) increase in cf-PWV after acute RE, compared to rest. In conclusion, this study demonstrates that acute free-weight and weight-machine RE are associated with transient increases in measures of pulse wave reflection and aortic stiffness, with reductions in myocardial perfusion. These data demonstrate that both modalities result in significant stress on the myocardium during recovery, while simultaneously increasing pressure on the aorta for at least 10–20 min. [ABSTRACT FROM AUTHOR]

Bioelectrical impedance (BI) has been widely used but clarification about the behaviour of raw BI measurements under specific athletic conditions is required. Thus, we determined the usefulness of raw BI measures in tracking body fluids changes during the preparation period prior to competition in elite Judo athletes. At baseline (weight stability), 27 male athletes were evaluated (23.2 ± 2.8y) and again 1–3 days before competition (∼1–2 months apart). Athletes were free to gain/lost weight based upon specific competition needs. Using dilution techniques (deuterium and bromide), total-body water (TBW) and extracellular water were estimated, and intracellular water calculated as TBW minus extracellular water. Body fluid distribution was determined as Extra-to-/Intracellular water (E/I). Fat and fat-free mass (FFM) was assessed by dual-energy x-ray absorptiometry. Resistance, reactance, and phase angle (PhA) were obtained from bioelectrical impedance spectroscopy (50-kHz frequency). No differences in raw BI measures were observed between athletes that lost (N = 17) or gain weight (N = 10), except for fat, FFM, extracellular water, and EI (p < 0.05). After adjusting for FFM and height, resistance explained TBW (β = −0.047, p = 0.002) and extracelular water (β = −0.025, p = 0.001). Reactance explained ECW (β = −0.098, p = 0.004) and EI (β = −0.004, p = 0.006), while PhA predicted TBW (β = 1.609, p = 0.047), ICW (β = 1.899, p = 0.001) and EI (β = −0.056, p = 0.001). Regardless of body composition changes, athletes who increase reactance and resistance reduced extracellular water and body fluids while those who raised PhA increased intracellular water. Judo athletes who reduced weight, decreased FFM but cellular health was not compromised, as PhA remained stable and, consequently, cell hydration. [ABSTRACT FROM AUTHOR]

The effect of rapid energy restriction-induced weight loss on judo-related performance remains unclear, and there is a paucity of information regarding the influence of the fight successions during competition. Thus, the aim of this study was to compare the cumulative effect of judo fights on physical performance, biological and psychological profiles, of national judo competitors with vs without rapid weight loss. After one month of weight maintenance (Baseline), 20 subjects were randomly divided into two groups the week before a simulated competition: (i) a Weight Loss group (WL; weight loss ≥ 3% of body mass); (ii) a Weight Stable group (WS). The simulated competition was composed of five fights (F1 to F5) separated by 30 min rest. Anthropometric assessments were performed at baseline and on the morning of the simulated competition (T0). Psychological, biological and physical assessments (maximal handgrip strength, upper limb anaerobic capacity) were performed at T0 and after each fight. The variation of body mass between baseline and T0 was significantly different between groups (+1.2% vs −3%; p <.01). The dimensions of the Profile of Mood State questionnaire, the rate of perceived exertion, ammonia, urea and free fatty acid concentrations, maximal strength and time sustained at maximal strength showed a significant group x time interaction at F4 and F5. The study shows that cumulative fights lead to uncoupled responses in physical, psychological and biological parameters in judo competitors who underwent or not rapid weight loss. Specific recovery strategies in terms of nutrition and active recovery should be considered. [ABSTRACT FROM AUTHOR]

Comfort as an essential parameter for running footwear is gaining importance in footwear research and development, and has also been proposed to decrease injury rate and improve metabolic demand in the paradigm of the comfort filter. The aims of this study were to determine differences in oxygen consumption and biomechanical variables associated with lower extremity injuries in response to running shoes of differing comfort. Fifteen male runners attended two testing sessions including an incremental lactate threshold test, a comfort assessment and treadmill running trials for the biomechanical and physiological measurements. Statistical analyses were performed on oxygen consumption, spatio-temporal variables including foot-ground angle and coupling angle variability of 12 couplings in five stride phases. No decrease in oxygen consumption was found in the most preferred shoe condition. Investigation of potential biomechanical contributors to changes in metabolic demands revealed differences in the stride rate between the most and least preferred condition. In coupling angle variability analyses, only one coupling (ankle dorsiflexion/plantarflexion to knee varus/valgus) yielded a significant difference between conditions in the phase including the touch down. Based on the findings of this study, previous suggestions regarding positive effects of enhanced footwear comfort during running cannot be supported – neither on economy nor on injury prevention perspective. However, a prospective study of lower extremity injury combined with measurements of biomechanical and physiological variables seems to be required for a definite support or contradiction of the comfort filter. [ABSTRACT FROM AUTHOR]

In adolescent soccer, 23% of the distance covers happens at speeds above onset of blood lactate accumulation which suggests that lactate kinetics may be important for soccer performance. We sought to determine the effectiveness of sprint interval training (SIT) on changing performance and lactate kinetics in adolescent soccer players. Thirteen elite soccer academy players (age 15 ± 0.5y) underwent baseline testing (0–10 m and 10–20 m sprint performance, Wingate anaerobic Test (WaNT) with blood lactate measurements and incremental VO2 peak test) before being allocated to control or SIT group. The control group maintained training whilst the HIT group carried out twice-weekly all-out effort cycle sprints consisting of 6 × 10 s sprint with 80 s recovery. There were significant time x group interactions for 10–20 m sprint time (Control pre: 1.32 ± 0.07 s post: 1.35 ± 0.08 s; SIT pre: 1.29 ± 0.04 s post: 1.25 ± 0.04 s; p = 0.01), Peak Power (Control pre: 13.1 ± 1.3 W.kg−1 post: 13.2 ± 1.47 W.kg−1; SIT pre: 12.4 ± 1.3 W.kg−1 post: 15.3 ± 0.7 W.kg−1; p = 0.01) and time to exhaustion (Control pre: 596 ± 62 s post: 562 ± 85 s; SIT pre: 655 ± 54 s post: 688 ± 55 s; p = 0.001). The changes in performance were significantly correlated to changes in lactate kinetics (power: r = 0.55; 10–20 m speed: r = −0.54; time to exhaustion: r = 0.55). Therefore, cycle based SIT is an effective training paradigm for elite adolescent soccer players and the improvements in performance are associated with changes in lactate kinetics. [ABSTRACT FROM AUTHOR]

Each stretch-shortening-cycle (SSC) in elite sports (e.g. jumping, cycling), is characterised by utilising optimal movement-parameters (e.g. muscle shortening velocity), for maximum power (jump height, cycle velocity). It is however unclear if relevant SSC movement-parameters in rowing, such as stroke rate and gearing, have to be maximised to obtain maximum power output or if an optimum relation emerges. Thus, we measured rowing-power (Prow), leg-power (Pleg) and work-per-stroke (WPS) at of varying stroke rates (20–45 spm), gearings (lever-changes 0.87–0.90 m) and drag factors (100–180 Ws3/m3) during rowing. Experienced sub-elite young athletes performed sprint-series on (single scull, n = 69, 20 ± 2 years, 186 ± 7 cm, 84 ± 9 kg) and off the water (rowing-ergometer, n = 30, 19 ± 3 years, 185 ± 11 cm, 77 ± 19 kg). Prow increased with stroke rate for ergometer-test (r = 0.97, p < 0.001) and boat measurement (r = 0.98, p < 0.001) by 2.7%/stroke and 4.4%/stroke, respectively. Interestingly, stroke rate had a high impact on WPS (r = 0.79, p < 0.001) during boat measurement, compared to no (or specifically no high) impact on WPS (r = −0.10, p = 0.166) during ergometer-measurements. Drag factor (ergometer: r = 0.83, p < 0.001) and gearing (boat: r = 0.60, p < 0.001) yielded moderate to high correlations to Prow. These results indicate that no optimum stroke rate, gearing and drag factor exist for maximum power in rowing (sprint-measurement-range). Accordingly, the measurements yielded maximum power for maximum stroke rate, gearing, and drag factor. [ABSTRACT FROM AUTHOR]

Gas-collection masks are used as a comfortable alternative to the traditional mouthpiece and noseclip during exercise testing protocols in human performance laboratories. However, these masks may introduce potential problems which could affect metabolic and ventilatory parameters, including gas leaks and added dead space. Therefore, the purpose of this study was to compare breathing mechanics, gas exchange variables and ratings of perceived breathlessness (RPB) during high-intensity exercise between a mouthpiece and face mask. Fourteen men [⩒O2peak = 55.3 ± 7.3 ml·kg−1·min−1] were recruited to perform 6 min of cycle ergometry (Velotron Pro, RacerMate, Inc., Seattle, WA) at a work rate corresponding to 90% of ⩒O2peak while breathing on either (1) a mouthpiece (Hans Rudolph, KC, KS) with nose clip, or (2) a face mask (7450, Hans Rudolph, KC, KS). The difference in ⩒E between the mouthpiece (156.8 ± 23.3 L/min) and face mask (153.3 ± 21.8 L/min) was not significant (p = 0.534). Similarly, there were no significant differences in breathing mechanics, gas exchange variables or RPB. These data suggest that the facemask can continue to be used interchangeably with the mouthpiece and may even be a more comfortable alternative during high-intensity exercise. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare if an acute exercise session of high-load resistance training (HL-RT, e.g. 70% of 1 repetition-maximum, 1 RM) induces a higher magnitude of muscle damage compared with a RT protocol with low-loads (e.g. 20% 1 RM) associated with partial blood flow restriction (LL-BFR), and investigate the recovery in the days after the protocols. We used an unilateral crossover research design in which 10 young women (22(2) y; 162(5) cm; 66(11) kg) performed HL-RT and LL-BFR in a randomized, counterbalanced manner with a minimum interval of 2 weeks between protocols. Indirect muscle damage markers were evaluated before and once a day for 4 days into recovery. Main results showed decreases of 8–12% at 24–48 h in maximal voluntary isometric and concentric contraction torques (P < 0.03), and changes in muscle architecture markers (P < 0.03) for HL-RT and LL-BFR, with no differences between protocols (P > 0.05). Moreover, delayed onset muscle soreness increased only after LL-BFR (P < 0.001). We conclude that an acute bout of low volume HL-RT or LL-BFR to failure resulted in edema-induced muscle swelling, but do not induce major or long-lasting decrements in muscle function and the level of soreness promoted from LL-BFR was mild. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine how running experience affects leg stiffness (Kleg) and spring-mass characteristics during running stages associated with the onset of blood lactate accumulation (OBLA). Seven trained (66.9 ± 4.8 kg; 182 ± 4.0 cm; 23.1 ± 3.1 years) and 13 untrained (78.5 ± 7.6 kg; 182 ± 3.0 cm; 20.3 ± 1.5 years) runners completed an incremental treadmill run. Running velocity was increased by 1 km.h−1 every four minutes and blood lactate samples were taken at every stage, in addition to a 10 s video recording using 'Runmatic'. Once 4 mmolL−1 (OBLA; the second lactate turn point) had been reached one more stage was completed. Spring-mass characteristics across groups and at pre-OBLA, OBLA and post-OBLA were compared. The velocity at OBLA was higher for the trained runners compared to the untrained runners (18 ± 0.7 vs 11 ± 1.3 km.h−1, p < 0.001). Kleg was similar between untrained and trained runners across each stage (15.8 ± 0.3 vs 14.3 ± 0.3 kN.m) and did not change between stages, yet spring-mass characteristics differed between groups. Vertical stiffness increased in the trained runners from pre-OBLA to post-OBLA (45.5 ± 3.35–51.9 ± 3.61 kN−1), but not in untrained runners (35.0 ± 5.2–39.6 ± 5.7 kN−1). Kleg was strongly related to Fpeak for trained runners only (r = 0.79; untrained runners, r = 0.34). Kleg was unaffected by physiological training status and was maintained across all OBLA stages. Trained runners appear to have optimised their spring-mass system in a homogenous manner, whilst less consistent spring-mass characteristics were observed in untrained runners. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate whether the change in (sub)maximal heart rate after intensified training is associated with the change in performance. Thirty subjects were recruited who performed cardiopulmonary exercise tests to exhaustion 2 weeks before (pre), 1 week after (post) and 5 weeks after (follow-up) an 8-day non-competitive amateur cycling event (TFL). The exercise volume during the TFL was 7.7 fold the volume during the preparation period. Heart rate and cardiopulmonary parameters were obtained at standardised absolute submaximal workloads (low, medium and high intensity) and at peak level each test. Subjects were classified as functionally overreached (FOR) or acute fatigued (AF) based on the change in performance. No differences between FOR and AF were observed for heart rate (P =.51). On total group level (AF + FOR), post-TFL heart rate decreased significantly at low (−4.4 beats·min−1, 95% CI [−8.7, −0.1]) and medium (−5.5 beats·min−1 [−8.5, −2.4]), but not at high intensity. Peak heart rate decreased −3.4 beats·min−1 [−6.1, −0.7]. O2pulse was on average 0.49 ml O2·beat−1 [0.09, 0.89] higher at all intensities after intensified training. No changes in ⩒O2 (P =.44) or the ventilatory threshold (P =.21) were observed. Pearson's correlation coefficients revealed negative associations between heart rate and O2pulse at low (r = −.56, P <.01) and medium intensity (r = −.54, P <.01), but not with ⩒O2 or any other submaximal parameter. (Sub)maximal heart rate decreased after the TFL. However, this decrease is unrelated to the change in performance. Therefore, heart rate seems inadequate to prescribe and monitor intensified training. [ABSTRACT FROM AUTHOR]

Aging has been related with a decline in the ability to handle protein folding, which leads to endoplasmic reticulum stress and alterations in unfolded protein response (UPR). Importantly, physical activity could activate the UPR and attenuate or prevent age-induced endoplasmic reticulum (ER) dysfunction. The current study evaluated the effects of a resistance exercise on UPR and mitochondrial functions in peripheral blood mononuclear cells (PBMCs) from elderly subjects. Thirty healthy women and men (age, 72.8, sx− = 2.2 years) were randomized to a training group, which performed an 8-week resistance training programme, or a control group, which followed their daily routines. The phosphorylation of PERK and IRE1, as well as ATF4, and XBP1 protein expression, significantly increased following the training, while expression of BiP, AFT6 and CHOP remain without changes. Additionally, the intervention also induced an increase in PGC-1α and Mfn1 protein levels, while no changes were found in Drp1 expression. Finally, the resistance protocol was not able to activate PINK1/Parkin and Bnip3/Nix pathways. The results obtained seem to indicate that 8-week resistance exercise activates the UPR, stimulates mitochondrial biogenesis, maintains mitochondrial dynamics and prevents mitophagy activation by unfolded proteins in PBMCs from elderly subjects. [ABSTRACT FROM AUTHOR]

The differences between the racket-arm acceleration mechanisms during open and square stance forehand groundstrokes in tennis were examined by quantifying the mechanical work done on the racket arm. We studied 13 advanced tennis players as they performed these strokes at maximum effort and calculated the work using inverse dynamics. The racket head speed was similar between the open and square stances. In the open stance, the lack of weight shifting towards the hitting direction resulted in a lower velocity for the shoulder joint centre in the hitting direction than in the square stance, and less work was done by the shoulder joint force in the hitting direction in the open stance than in the square stance (0.30 ± 0.11 J·kg-1 vs. 0.38 ± 0.16 J·kg-1; p = 0.005). However, in the open stance, the torso rotated more towards the hitting direction and had more upward acceleration, which resulted in more work done by the sideways and upward shoulder joint forces than in the square stance (sideways: 0.07 ± 0.09 J·kg-1 vs. 0.05 ± 0.09 J·kg-1, p = 0.046; upward: 0.08 ± 0.09 J·kg-1 vs. 0.04 ± 0.07 J·kg-1, p = 0.002). Thus, the greater work done by the sideways and upward shoulder joint forces compensated for the lesser work done by the shoulder joint force in the hitting direction in the open stance. In both stances, mainly the horizontal flexion torque and internal rotation torque at the shoulder increased the energy of the racket arm. [ABSTRACT FROM AUTHOR]

Rugby Union scrumming puts the spine under a high degree of loading. The aim of the current study was to determine how sagittal hip range of motion and quadriceps fatigue influence force output, spinal posture, and activation of the trunk and quadriceps muscles in rugby scrumming. Measures of sagittal hip flexion/extension range of motion were collected from 16 male varsity and club first XV level participants. Sagittal spine motion (electromagnetic motion capture), trunk and quadriceps activation (electromyography), and applied horizontal compressive force (force plate) were measured during individual machine scrumming. Participants performed a 5-trial scrum block involving 5 s of contact with 1–2 min recovery between each trial. They then performed a fatiguing protocol (wall sit to failure) and immediately returned to the scrum machine to perform another five trials. Though there was no significant influence of fatigue on the horizontal compressive force applied during contact (P =.83), there was a 52% increase in cervical flexion (P <.001), as well as decreased (18–23% lower) abdominal and erector spinae muscle activation (P <.05). Furthermore, quadriceps activation decreased (12–25% lower) over the course of the initial scrum block but increased (13–15% higher) in the post fatigue block (P <.05). Although athletes were able to maintain force output following the fatiguing wall sit task, there is the potential that they may be at an increased risk of spinal injury due to the combination of increased flexion and high-applied compressive force; a combination which has been shown to increase the likelihood of intervertebral disc herniation. [ABSTRACT FROM AUTHOR]

Background: We aimed to evaluate the influence of the level of effort during four basic resistance exercises leading to muscular failure on intraocular pressure (IOP) and ocular perfusion (OPP), as well as the role of exercise type and sex. Methods: Twenty-five young adults (12 women) performed 10 repetitions against their 10-RM (repetition maximum) load in the squat, military press, biceps curl and calf raise exercises. IOP was measured before, during and after exercise, whereas OPP was indirectly assessed before and after each exercise. Results: There was a progressive IOP rise during exercise (p < 0.001, η² = 0.531), which was dependent on exercise type (p = 0.020, η² = 0.125). The squat exercise induced higher IOP increments in comparison to the other exercises (corrected p-values < 0.001), and higher IOP values were found for the military press and biceps curl than for the calf raise exercise (corrected p-values = 0.012 and 0.002). OPP exhibited a significant reduction when leading to muscular failure (p = 0.001, η² = 0.364), being statistically significant for the squat and military press exercises (corrected p-values = 0.037 and 0.047). No effect of sex was found for IOP and OPP (p > 0.05). Conclusions: A single set of resistance training leading to muscular failure causes an instantaneous and progressive IOP rise in healthy young individuals. These IOP rises depend on exercise type (squat > military press = biceps curl > calf raise), but not on participant´s sex. OPP diminished as a consequence of performing resistance training exercise, being statistically significant for the squat and military press exercises. Future studies should include glaucoma patients aiming to corroborate the generalizability of our findings. [ABSTRACT FROM AUTHOR]

Wrist movements have been identified as an important factor in producing a successful golf swing, with their complex motion influencing both club head velocity and orientation. However, a detailed analysis of wrist angles is lacking in the literature. The purpose of this study was to determine kinematics across wrists and club head characteristics during the golf swing under weak, neutral and strong grip conditions. Twelve professional male golfers executed 24 shots using a driver under three grip conditions. A six degrees of freedom analysis of the hand with respect to the distal forearm was performed using a 10-camera three-dimensional motion capture system. Differences in joint angles were explored using repeated measures ANOVAs at key swing events (onset, top of backswing and impact), in addition club head velocity and clubface angle at impact were also explored. Main findings revealed significant differences in flexion/extension and internal/external rotation for both wrists at all swing events, whereas fewer significant interactions were found in ulnar/radial deviation across grips for both wrists at all events. Clubface angle only differed significantly between the weak and the strong and neural grips, presenting a more 'open' clubface to the intended hitting direction. This study is the first to explore tri-planar wrist movement and the effect of different grips, such analysis has implications for coaching knowledge and practice and should inform future research into different aspects of skill, technique analysis and may inform injury mechanisms/prevention. [ABSTRACT FROM AUTHOR]

The present study assessed neuromuscular and corticospinal changes during and after a fatiguing submaximal exercise of the knee extensors in different modes of muscle contraction. Twelve subjects performed two knee extensors exercises in a concentric or eccentric mode, at the same torque and with a similar total impulse. Exercises consisted of 10 sets of 10 repetitions at an intensity of 80% of the maximal voluntary isometric contraction torque (MVIC). MVIC, maximal voluntary activation level (VAL) and responses of electrically evoked contractions of the knee extensors were assessed before and after exercise. Motor evoked potential amplitude (MEP) and cortical silent period (CSP) of the vastus medialis (VM) and rectus femoris (RF) muscles were assessed before, during and after exercise. Similar reductions of the MVIC (−13%), VAL (−12%) and a decrease in the peak twitch (−12%) were observed after both exercises. For both VM and RF muscles, MEP amplitude remained unchanged during either concentric or eccentric exercises. No change of the MEP amplitude input-output curves was observed post-exercise. For the RF muscle, CSP increased during the concentric exercise and remained lengthened after this exercise. For the VM muscle, CSP was reduced after the eccentric exercise only. For a similar amount of total impulse, concentric and eccentric knee extensor contractions led to similar exercise-induced neuromuscular response changes. For the two muscles investigated, no modulation of corticospinal excitability was observed during or after either concentric or eccentric exercises. However, intracortical inhibition showed significant modulations during and after exercise.  [ABSTRACT FROM AUTHOR]

Objective: To analyse the effect of resistance training (RT) frequency on muscle mass, appendicular lean soft tissue, insulin-like growth factor 1 (IGF-1), testosterone, and their changes with detraining in older women. Methods: Forty-five physically independent older women (≥ 60 years) were randomly assigned to perform RT either two (G2X, n = 21) or three times/week (G3X, n = 24), during 12 weeks (8 exercises, 1 set of 10-15 repetition maximum). Muscle mass and appendicular lean soft tissue, IGF-1, testosterone, and dietary intake were measured at pre-training, post-training, and after detraining (12 weeks). Results: Muscle mass and appendicular lean soft tissue significantly increased post-training (G2X = +5.5% and G3X = +5.8%, P < .0001) with no differences between groups, and gains were retained after detraining (G2X = 100% and G3X = 99%, P < .0001). IGF-1 and dietary intake did not change for the groups during the study. Testosterone did not change post-training but significantly decreased after detraining (G2X = −21% and G3X = −50%, P < .0001). Conclusion: We conclude that lower RT frequency is as effective as higher frequency to improve muscle mass and appendicular lean soft tissue, and to maintain testosterone and IGF-1. Additionally, detraining may reduce testosterone regardless of RT frequency. These results are specifically for community-dwelling older women and may not be generalized to other populations. [ABSTRACT FROM AUTHOR]

Excessive foot pronation during gait is a risk factor in medial tibial stress syndrome (MTSS). Arch-support foot-orthoses are commonly used to manage overpronation, but it is unknown whether it is effective to manage MTSS. The present study investigated the effects of bilateral foot orthoses during running on dynamic foot-pressure distribution patterns in recreational runners with MTSS. Fifty novice (started within the last 4 months) runners diagnosed with MTSS (20.7 ± 2.2 years; 71.1 ± 8.6 kg; 1.78 ± 0.07 m; mean ± SD) and 50 anthropometrically-matched healthy novice runners (21.9 ± 2.4 years; 71.4 ± 8.8 kg; 1.73 ± 0.07 m) participated in this study. The dynamic foot-pressure distribution during running with and without bilateral arch-support foot-orthoses was measured using pedobarography. MTSS novice runners have more medially directed pressures during the touchdown phase of the forefoot flat (p = 0.009) and heel off (p = 0.009), and a lateral pressure distribution during forefoot push-off phase (p = 0.007) during running than healthy runners. When using the arch-support foot-orthoses the foot-pressure distribution during all phases was not significantly different from that seen in participants without MTSS. These findings indicate that during running the medial shift of foot pressures during the loading response phase and the lateral shift during the propulsion phase of foot roll-over in MTSS are effectively corrected by using arch-support foot-orthoses. The use of such arch-support orthoses may thus be an effective tool to normalize foot-pressure distribution patterns during running, indicating the potential to treat and prevent MTSS in recreational runners. [ABSTRACT FROM AUTHOR]

Purpose: The effect of breakfast omission on evening high-intensity exercise performance has not previously been studied. Methods: In a randomised and counterbalanced cross-over design, 10 competitive rowers (2 male, 8 female; mean ± SD: age 21 ± 2 y, height 176 ± 7 cm, weight 76 ± 12 kg, body fat 19.7 ± 6.8%) completed two trials (individualised carbohydrate-rich breakfast (BT; 831 ± 67 kcal eaten before 09:00) and no-breakfast (NBT; extended overnight fast until 12:00)). Following ad libitum afternoon food intake, participants completed a 2000-m time-trial on a rowing ergometer between 16:30 and 18:00. Appetite and energy intake were measured throughout the day, whilst power output, time, heart rate, blood lactate, blood glucose and RPE were assessed during the time trial. Results: Appetite ratings were higher throughout the morning in NBT compared with BT, but there were no differences in ratings in the afternoon. Energy intake at lunch was greater NBT compared with BT (1236 ± 594 vs 836 ± 303 kcal, p < .05), which partly compensated for breakfast omission, although overall energy intake tended to be lower in NBT compared with BT (1236 ± 594 vs 1589 ± 225 kcal, p = .08). The time taken to complete the 2000-m time trial was greater in NBT compared with BT (469.2 ± 43.4 vs 465.7 ± 43.3 s; p < .05). No differences in heart rate, blood glucose and blood lactate responses were apparent, but overall RPE was higher in NBT compared with BT (17.8 ± 0.9 vs 16.7 ± 0.7 au, p < .05). Conclusion: The omission of a carbohydrate-rich breakfast impaired evening performance during a 2000-m rowing time trial. This finding has implications for optimising evening high-intensity exercise performance. [ABSTRACT FROM AUTHOR]

The aim of this study was to quantify the food intake of an International Cyclist Union (UCI) World Tour professional cyclist team and to analyse changes in body composition during the Tour of Spain. Nine male professional road cyclists (31.3 ± 3.0 years) volunteered to participate in the study. Nutritional data were collected each day throughout the 3-week Tour by two trained investigators who weighed the food ingested by the cyclists. Mean nutritional intake of the cyclists was as follows: carbohydrate, 12.5 ± 1.8 g/kg/day of body weight (BW) (65.0 ± 5.9%); fat, 1.5 ± 0.5 g/kg/day BW (17.9 ± 5.6%); and protein, 3.3 ± 0.3 g/kg/day BW (17.1 ± 1.6%). Intake of all micronutrients, except for folate, vitamin D and potassium (which were 78.7%, 46% and 84% of Recommended Dietary Allowances (RDA), respectively), exceeded the RDA. Height, weight, skinfolds, circumferences and diameters were taken following the guidelines outlined by the International Society for the Advancement of Kinanthropometry. Body density, body fat percentage, muscle mass, total muscle mass and fat mass of the arms and thighs were calculated. Percentage body fat, fat mass and upper arm fat mass significantly decreased (p <.05) after the Tour independent of the equation method used in the calculations. Total muscle mass remained unchanged. Generally, this sample of cyclists consumed more protein and less fat than the recommended amount and had low weight, BMI and fat mass. It is suggested that sports nutritionists design personalised diets in order to maintain a correct proportion of nutrients as well as controlling possible anthropometrical changes that could affect performance.  [ABSTRACT FROM AUTHOR]

Carnosine was originally discovered in skeletal muscle, where it exists in larger amounts than in other tissues. The majority of research into the physiological roles of carnosine have been conducted on skeletal muscle. Given this and the potential for muscle carnosine content to be increased with supplementation, there is now a large body of research examining the ergogenic effects (or otherwise) of carnosine. More recent research, however, points towards a potential for carnosine to exert a wider range of physiological effects in other tissues, including the brain, heart, pancreas, kidney and cancer cells. Taken together, this is suggestive of a potential for carnosine to have therapeutic benefits in health and disease, although this is by no means without complication. Herein, we will provide a review of the current literature relating to the potential therapeutic effects of carnosine in health and disease. [ABSTRACT FROM AUTHOR]