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There is a lack of evidence on the additional benefits of combining caffeine (CAF) and creatine (CRE) supplementation on anaerobic power and capacity. Thus, the aim of the present study was to test the effects of combined and isolated supplementation of CAF and CRE on anaerobic power and capacity. Twenty-four healthy men performed a baseline Wingate anaerobic test and were then allocated into a CRE (n = 12) or placebo (PLA; n = 12) group. The CRE group ingested 20 g/day of CRE for 8 days, while the PLA group ingested 20 g/day of maltodextrin for the same period. On the sixth and eighth days of the loading period, both groups performed a Wingate anaerobic test 1 hr after either CAF (5 mg/kg of body mass; CRE + CAF and PLA + CAF conditions) or PLA (5 mg/kg of body mass of cellulose; CRE + PLA and PLA + PLA conditions) ingestion. After the loading period, changes in body mass were greater (p <.05) in the CRE (+0.87 ± 0.23 kg) than in the PLA group (+0.13 ± 0.27 kg). In both groups, peak power was higher (p =.01) in the CAF (1,033.4 ± 209.3 W) than in the PLA trial (1,003.3 ± 204.4 W), but mean power was not different between PLA and CAF trials (p >.05). In conclusion, CAF, but not CRE ingestion, increases anaerobic power. Conversely, neither CRE nor CAF has an effect on anaerobic capacity. [ABSTRACT FROM AUTHOR]

It has been assumed that exercise intensity variation throughout a cycling time trial (TT) occurs in alignment of various metabolic changes to prevent premature task failure. However, this assumption is based on target metabolite responses, which limits our understanding of the complex interconnection of metabolic responses during exercise. The current study characterized the metabolomic profile, an untargeted metabolic analysis, after specific phases of a cycling 4‐km TT. Eleven male cyclists performed three separated TTs in a crossover counterbalanced design, which were interrupted at the end of the fast‐start (FS, 600 ± 205 m), even‐pace (EP, 3600 ± 190 m), or end‐spurt (ES, 4000 m) phases. Blood samples were taken before any exercise and 5 min after exercise cessation, and the metabolomic profile characterization was performed using Nuclear Magnetic Resonance metabolomics. Power output (PO) was also continually recorded. There were higher PO values during the FS and ES compared to the EP (all p < 0.05), which were accompanied by distinct metabolomic profiles. FS showed high metabolite expression in TCA cycle and its related pathways (e.g., glutamate, citric acid, and valine metabolism); whereas, the EP elicited changes associated with antioxidant effects and oxygen delivery adjustment. Finally, ES was related to pathways involved in NAD turnover and serotonin metabolism. These findings suggest that the specific phases of a cycling TT are accompanied by distinct metabolomic profiles, providing novel insights regarding the relevance of specific metabolic pathways on the process of exercise intensity regulation. Highlights: Untargeted metabolomic profile analysis may reveal unexplored bioenergetic pathways activated throughout a self‐paced cycling time trial.Exercise intensity variations throughout a cycling time trial are accompanied by different blood serum metabolomic profiles.The current new insights may encourage future investigation on the underpinning mechanisms of specific metabolomic profiles according to each time trial phase. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effects of caffeine (CAF) on performance during high- and long-jump competitions. Methods: Using a crossover and double-blind design, 6 well-trained high jumpers and 6 well-trained long jumpers performed a simulation of a high- and long-jump competition 60 minutes after ingesting a capsule containing either 5 mg·kg−1 body mass of anhydrous CAF or a placebo. The high jumps were video recorded for kinematic analysis. The velocity during the approach run of the long jump was also monitored using photocells. Results: CAF improved jump performance (ie, the highest bar height overlap increased by 5.1% [2.3%], P =.008), as well as enhancing the height displacement of the central body mass (+1.3% [1.7%], P =.004) compared with the placebo. CAF had no ergogenic effect on jump distance (P =.722); however, CAF increased the velocity during the last 10 m of the long jump (P =.019), and the percentage of "foul jumps" was higher than that expected by chance in the CAF group (80.5% [12.5%], χ2 = 13.44, P <.001) but not in the cellulose condition (58.3% [22.9%], χ2 = 1.48, P =.224). Conclusion: CAF ingestion (5 mg·kg−1 body mass) improves high-jump performance but seems to negatively influence technical aspects during the approach run of the long jump, resulting in no improvement in long-jump performance. Thus, CAF can be useful for jumpers, but the specificity of the jump competition must be taken into account. [ABSTRACT FROM AUTHOR]

The effects of plyometric training (PT) on middle- and long-distance running performances are well established. However, its influence on pacing behaviour is still unclear. The aim of this study was to evaluate the effects of PT on pacing behaviour. In addition, verify whether the adaptations induced by PT would change ratings of perceived exertion (RPE) and/or affective feelings during the race. Twenty-eight male runners were assigned to two groups: control (C) and PT. PT held two weekly PT sessions for eight weeks. Drop jump (DJ) performance, 10-km running performance, pacing behaviour, RPE and affective feelings, VO2peak, ventilatory thresholds (VT1 and VT2), peak treadmill speed (PTS), and running economy (RE) were measured. For group comparisons, a mixed model analysis for repeated measures, effect size (ES) and 90% confidence interval (90% CI) were calculated for all dependent variables. Significant differences pre-to-post was observed for PT group in DP (7.2%; p ≤ 0.01; ES = 0.56 (0.28–0.85)) and RE (4.5%; p ≤ 0.05; ES = −0.52 ((−0.73 to −0.31)) without changes in pacing behaviour. While PT was effective for improving DJ and RE, there is no evidence that pacing behaviour, RPE or affective feelings are directly affected by these adaptations during a 10-km time trial run. [ABSTRACT FROM AUTHOR]

The current study analysed the effect of distinct pacing profiles (i.e. U, J, and inverted J) in the perceptual responses and neuromuscular fatigue (NMF) development following a 4-km cycling time trial (TT). Twenty-one cyclists with similar training status were allocated into three different groups based on their pacing profile spontaneously adopted during TT. Rating of perceived exertion (RPE), oxygen uptake (⩒O2) and heart rate (HR) were continuously recorded. NMF was assessed by using isometric maximal voluntary contractions (IMVC), while the central [i.e. voluntary activation (VA)] and peripheral fatigue of knee extensors [i.e. peak torque of potentiated twitches (TwPt)] were evaluated using electrically evoked contractions performed pre and 2 min after the TT. TT performance was not different amongst pacing profiles (U = 377 ± 20 s; J = 392 ± 23 s; J-i = 381 ± 20 s) (all P > 0.05). RPE, ⩒O2 and HR increased similarly throughout the TT regardless the pacing strategy (all P > 0.05). Similarly, IMVC (U = −9.9 ± 8.8; J = −9.6 ± 4.5%; J-i = −13.8 ± 11.3%), VA (U = −2.3 ± 1.7%; J = −5.4 ± 2.2%; J-i = −6.4 ± 4.5%) and TwPt (U = −32.5 ± 12.0%; J = −29.5 ± 8.0%; J-i = −33.6 ± 13.6%) were similar amongst pacing profiles (all P > 0.05). Therefore, endurance athletes with similar training status showed the same perceived responses and NMF development regardless the pacing profile spontaneously adopted. It was suggested that these responses occurred in order to preserve a similar rate of change in systemic responses (i.e. RPE, ⩒O2 and HR) and NMF development, ultimately resulting in same TT performance. Different pacing profiles resulted in the same performance in a 4-km cycling time trial. The similar performance might be due to achievement of the same sensory tolerance limit. There was no difference for perceptual, metabolic and neuromuscular fatigue responses. [ABSTRACT FROM AUTHOR]

The airflow restriction mask (ARM) is a practical and inexpensive device for respiratory muscle training. Wearing an ARM has recently been combined with high‐intensity interval exercise (HIIE), but its effect on neuromuscular fatigue is unknown. The present study investigated the effects of ARM wearing on neuromuscular fatigue after an HIIE session. Fourteen healthy men performed two HIIE sessions (4 × 4 min at 90% HRmax, 3 min recovery at 70% HRmax) with or without an ARM. Neuromuscular fatigue was quantified via pre‐ to post‐HIIE changes in maximal voluntary contraction (MVC), voluntary activation (VA, central fatigue), and potentialized evoked twitch force at 100, 10, and 1 Hz (peripheral fatigue). Blood pH and lactate were measured before and after the HIIE session, while HR, SpO2, dyspnea, physical sensation of effort (P‐RPE), and Task Effort and Awareness (TEA) were recorded every bout. The exercise‐induced decrease in MVC was higher (p < 0.05) in the ARM (−28 ± 12%) than in the Control condition (−20 ± 11%). The VA decreased (p < 0.05) in the ARM (−11 ± 11%) but not in the control condition (−4 ± 5%, p > 0.05). Pre‐ to post‐HIIE declines in evoked twitch at 100, 10, and 1 Hz were similar (p > 0.05) between ARM and control conditions (ARM: −18 ± 10, −43 ± 11 and −38 ± 12%; Control: −18 ± 14, −43 ± 12 and −37 ± 17%). When compared with the control, the HIIE bout wearing ARM was marked by higher heart rate, plasma lactate concentration, dyspnea, P‐RPE and TEA, as well as lower SpO2 and blood pH. In conclusion, ARM increases perceptual and physiological stress during a HIIE, which may lead to a greater post‐exercise central fatigue. [ABSTRACT FROM AUTHOR]

Copyright of Applied Physiology, Nutrition & Metabolism is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Applied Physiology, Nutrition & Metabolism is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aimed to investigate whether isolated or combined carbohydrate (CHO) and caffeine (CAF) supplementation have beneficial effects on performance during soccer-related tests performed after a previous training session. Eleven male, amateur soccer players completed 4 trials in a randomized, double-blind, and crossover design. In the morning, participants performed the Loughborough Intermittent Shuttle Test (LIST). Then, participants ingested ( i) 1.2 g·kg−1 body mass·h−1 CHO in a 20% CHO solution immediately after and 1, 2, and 3 h after the LIST; ( ii) CAF (6 mg·kg−1 body mass) 3 h after the LIST; ( iii) CHO combined with CAF (CHO+CAF); and ( iv) placebo. All drinks were taste-matched and flavourless. After this 4-h recovery, participants performed a countermovement jump (CMJ) test, a Loughborough Soccer Passing Test (LSPT), and a repeated-sprint test. There were no main effects of supplementation for CMJ, LSPT total time, or best sprint and total sprint time from the repeated-sprint test ( p > 0.05). There were also no main effects of supplementation for heart rate, plasma lactate concentration, rating of perceived exertion (RPE), pleasure-displeasure, and perceived activation ( p > 0.05). However, there were significant time effects ( p < 0.05), with heart rate, plasma lactate concentration, RPE, and perceived activation increasing with time, and pleasure-displeasure decreasing with time. In conclusion, isolated and/or combined CHO and CAF supplementation is not able to improve soccer-related performance tests when performed after a previous training session. [ABSTRACT FROM AUTHOR]

Copyright of Applied Physiology, Nutrition & Metabolism is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article reports on research which was conducted to investigate the main bioenergetics and neuromuscular determinants of the time to exhaustion at the velocity corresponding to maximal oxygen uptake in recreational long distance runners. Researchers evaluated 20 runners. They found that total energy production, peak oxygen uptake and lower limb muscle power ability are the main physiological and neuromuscular determinants of time to exhaustion.

Background: the aim of this study was to compare between weight and gender categories the attack and pause times during the 2007 Taekwondo World Championship. Methods: a total of 88 rounds (47 male and 41 female contests) were analyzed. Results: there was no difference in attack/balancing times ratio between genders (0.13 ± 0.06 vs 0.13 ± 0.06, P > 0.05). The attack number was significantly higher in round 3 than in round 1 for all categories and genders. The balancing time was lower during the round 3 than round 1 for low-weight male and high-weight female categories. The delta of change from round 1 to 3 (round 3 - round 1) for attack time and attack/balancing times ratio were lower in male than female. Conclusions: female seems to intensify more the combat in the last round than male, and this seems be related to the weight division. [ABSTRACT FROM AUTHOR]

Exercise intensity variations throughout a cycling time trial (TT) might be influenced by subject's functional state. Purpose: The current study characterized the performance fatigability etiology, immediately after exercise cessation, and its relation to the dynamic changes in muscle O2 saturation (SmO2) at different TT phases. Methods: Twelve males performed three separated TT of different distances, in a crossover counterbalanced design, until the end of the fast-start (FS, 827 ± 135 m), even-pace (EP, 3590 ± 66 m), or end-spurt (ES, 4000 m) TT phases. Performance fatigability was characterized by using isometric maximal voluntary contractions (IMVC), whereas the maximal voluntary activation (VA) and contractile function of knee extensors (e.g., peak torque of potentiated twitches [TwPt]) were evaluated using electrically evoked contractions performed before and immediately after each exercise bouts. SmO2, power output (PO), and EMG were also recorded. Results: Immediately after the FS phase, there were lower values for IMVC (−23%), VA (−8%), and TwPt (−43%) (all P < 0.001), but no further changes were measured after EP (IMVC, −28%; VA, −8%; TwPt, −38%). After the ES phase, IMVC (−34%) and TwPt (−59%) further decreased compared with the previous phases (P < 0.05). There were lower SmO2 and higher EMG/PO values during FS and ES compared with EP phase. Conclusion: FS and EP phases had similar performance fatigability etiology, but ES showed further impairments in contractile function. This later finding might be due to the abrupt changes in SmO2 and EMG/PO because of the high exercise intensity during the ES, which elicited maximal decline in contractile function at the finish line. [ABSTRACT FROM AUTHOR]

Purpose The assumption that the curvature constant (W') of the power-duration relationship represents anaerobic work capacity is a controversial, unresolved question. We investigated if caffeine ingestion could increase total work done above critical power (CP), and if this would be accompanied by greater anaerobic energy expenditure and by an enhanced maintenance of maximal oxidative metabolic rate. Methods Nine men (26.6 ± 5.3 yr, ...O2max 40.6 ± 5.8 mL⋅kg-1⋅min-1) cycled until exhaustion at different exercise intensities on different days to determine the CP and W'. On separated days, participants cycled until exhaustion in the severe-intensity domain (136% ± 7% of CP) after ingesting either caffeine (5 mg⋅kg-1 body mass) or a placebo. Results Time to exhaustion was 34% longer with caffeine compared with placebo, and this was accompanied by a greater work done above CP (23.7 ± 5.7 vs 17.5 ± 3.6 kJ; 130% ± 30% vs 95% ± 14% of W', P < 0.01). Caffeine increased the aerobic energy expenditure (296.4 ± 91.0 vs 210.2 ± 71.9 kJ, P < 0.01), but not anaerobic lactic, anaerobic alactic, and total anaerobic (lactic + alactic) energy expenditure. The end values of heart rate and ventilation were higher with caffeine, but the ...O2 end was similar between conditions and was not different from ...O2max. Caffeine did not change time to reach ...O2max but increased time maintained at ...O2max (199.3 ± 105.9 vs 111.9 ± 87.1 s, P < 0.05). Conclusions Caffeine increased total work done above CP, but this was not associated with greater anaerobic work. Rather, this was associated with a higher tolerance to maintain exercise at maximal oxidative metabolic rate. [ABSTRACT FROM AUTHOR]