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Purpose: Physical exercise causes alterations in pain sensitivity. Many studies verified so-called exercise-induced analgesia caused by submaximal aerobic intensity. This study aimed to determine the effect of an endurance exercise to exhaustion on pain sensitivity of healthy young men.Method: Pressure pain thresholds (PPTs) [in Newton, (N)] of 50 healthy males (mean age 26 ± 4 years) were applied to knee, ankle and elbow joints as well as to the sternum and forehead. This was followed by a bout of cycling ergometer exercise to exhaustion. The whole process was repeated after 20 and 60 min respectively.Results: Endurance exercise to exhaustion decreased PPTs at sternum and forehead significantly, while thresholds at the joints were not affected. Pain thresholds at forehead and sternum declined 20 min after exercise with the forehead's threshold being more reduced. PPTs remain decreased until 60 min after exercise (forehead: from 43.6 ± 15.2 N to 36.6 ± 19.8 N to 37.2 ± 13.4 N; sternum: from 46.8 ± 21.0 N to 42.5 ± 17.1 N to 44.8 ± 18.2 N). Modulation of pain sensitivity showed large effect sizes over time for both landmarks (forehead w = 0.65; sternum w = 0.50).Conclusion: Exhaustive endurance exercise is followed by a hyperalgetic condition at forehead and sternum. This may be due to either a reduction in pain inhibiting or an activation in pain stimulating pathways. [ABSTRACT FROM AUTHOR]

Introduction: Non-local muscle fatigue (NLMF) is characterized by muscle performance impairments in a contralateral or remote non-exercised muscle(s) following a fatiguing protocol of a different muscle group(s). This topic is of interest as it affords insights into physiological determinants of muscle fatigue and may provide practical applications concerning the order of exercises in training and rehabilitation programs.Methods: A literature review was conducted using Web of Science, PubMed, and Google Scholar databases to evaluate the NLMF effects and possible underlying mechanisms. Overall, 35 studies with 58 outcome measures that met the inclusion criteria were identified.Results: The literature is conflicting with approximately half of the studies reporting NLMF effects (32 of 58 measurements). However, on closer examination 76% of outcome measures of the lower limbs reported NLMF effects (23 of 30 measurements) compared to only 32% in the upper body (9 of 28 measurements). Thus, it appears that NLMF effects may be muscle group dependent. Also, tests that involve prolonged or repetitive contractions provide clearer evidence of NLMF. Other variables potentially influencing the size of the NLMF effect include the fatigued muscle groups, the protocols used to elicit the fatigue, gender and training background of participants.Conclusion: While the NLMF literature is conflicting, certain variables appear to affect NLMF responses which can account for some of the discrepancies. Furthermore, the NLMF effects may be attributed to four different but interconnected pathways: neurological, biochemical, biomechanical and psychological. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed at determining the influence of the ACTN3 R577X polymorphism on muscle strength and muscle endurance in non-athletic young men. Methods: 266 healthy young men were included in this study. Each subject performed maximal isometric, concentric and eccentric contractions of the knee extensor muscles on an isokinetic dynamometer. Force depression, force enhancement and the fatigue index were derived from these data. In addition, handgrip strength, squat jump (SJ) and counter movement jump (CMJ) height were obtained. Results: Our group included 83 RR (31 %), 131 RX (49 %) and 52 XX (20 %) individuals. The muscle bone cross-sectional area of the thigh was 5 % higher in RR compared to XX individuals ( P = 0.033). RR genotypes showed 6 % higher handgrip strength compared to the XX group ( P = 0.047). They also jumped 5 % higher in both the SJ and CMJ tests ( P = 0.029; P = 0.031). No differences were found in force depression, force enhancement, isometric or eccentric strength. The relative concentric knee torque at 200°/s and at 300°/s was 7 and 8 % higher in RR compared to XX genotypes, respectively ( P = 0.049; P = 0.048). Also, the fatigue index was found to be 4 % lower in XX genotypes ( P = 0.037). Conclusions: Our findings are in agreement with the higher prevalence of the RR genotype in power-oriented activities. The better fatigue index of XX genotypes may be beneficial in endurance-type activities. [ABSTRACT FROM AUTHOR]

Metabolic measurement is still the criterion for investigation of the efficiency of mechanical work and for analysis of endurance performance in running. Metabolic demand may be expressed either as the energy spent per unit distance (energy cost of running, C) or as energy demand at a given running speed (running economy). Systematic studies showed a range of costs of about 20 % between runners. Factors affecting C include body dimensions: body mass and leg architecture, mostly calcaneal tuberosity length, responsible for 60-80 % of the variability. Children show a higher C than adults. Higher resting metabolism and lower leg length/stature ratio are the main putative factors responsible for the difference. Elastic energy storage and reuse also contribute to the variability of C. The increase in C with increasing running speed due to increase in mechanical work is blunted till 6-7 m s by the increase in vertical stiffness and the decrease in ground contact time. Fatigue induced by prolonged or intense running is associated with up to 10 % increased C; the contribution of metabolic and biomechanical factors remains unclear. Women show a C similar to men of similar body mass, despite differences in gait pattern. The superiority of black African runners is presumably related to their leg architecture and better elastic energy storage and reuse. [ABSTRACT FROM AUTHOR]

Objectives: The present study evaluated the effectiveness of a short and versatile daily exercise regime, named locomotion replacement training (LRT), to maintain muscle size, isometric strength, power, and endurance capacity of the leg muscles following 5 days of head-down tilt (HDT) bed rest. Methods: 10 male subjects (age 29.4 ± 5.9 years; height 178.8 ± 3.7 cm; body mass 77.7 ± 4.1 kg) performed, in random order, 5 days of 6° head-down tilt bed rest (BR) with no exercise (CON), or BR with daily 25 min of upright standing (STA) or LRT. Results: Knee extensor and plantar flexor cross-sectional area (CSA) were reduced by 2-3 % following bed rest ( P < 0.01) for CON and STA, yet maintained for LRT. Knee extensor isometric strength (MVC) decreased by 8 % for CON ( P < 0.05), was maintained for STA, and increased with 12 % for LRT ( P < 0.05). Plantar flexor MVC remained unaltered during the study. Maximum jump height declined (~1.5 cm) for all conditions ( P < 0.001). Neural activation and knee extensor fatigability did not change with bed rest. Bone resorption increased during BR and neither LRT nor STA was able to prevent or attenuate this increase. Conclusion: LRT was adequate to maintain muscle size and to even increase knee extensor MVC, but not muscle power and bone integrity, which likely requires more intense and/or longer exercise regimes. However, with only some variables showing significant changes, we conclude that 5 days of BR is an inadequate approach for countermeasure assessments. [ABSTRACT FROM AUTHOR]

Purpose: The present study evaluated the effects of peripheral heart action training compared with high intensity interval training on changes in autonomic regulation and physical fitness. Methods: Eighteen young adults (9 women, 9 men) (age 24 ± 3 years, BMI of 22.67 kg/m, V′O 32.89 ml/kg/min) were randomly assigned to either a high intensity interval training group ( n = 8) or a peripheral heart action training (PHA) group ( n = 10). Before and after training, maximal whole-body muscular strength, time series of beat-to-beat intervals for heart rate variability, and baroreflex sensitivity were recorded. Arterial baroreflex sensitivity and heart rate variability were estimated on both time and frequency domains. Physical fitness level was evaluated with maximum oxygen consumption test. Results: The effects of PHA whole-body resistance training increased muscular strength and maximum oxygen consumption, with an effect on vagal-cardiac control and cardiovagal baroreflex sensitivity. Conclusions: After 30 training sessions performed in 3 months, PHA resistance exercise promoted cardiovascular adaptations, with a decrease in the power spectral component of vascular sympathetic activity and an increase in the vagal modulation. Low-frequency oscillation estimated from systolic blood pressure variability seems to be a suitable index of the sympathetic modulation of vasomotor activity. This investigation also want to emphasize the beneficial effects of this particular resistance exercise training, considering also that the increase in muscular strength is inversely associated with all-cause mortality and the prevalence of metabolic syndrome, independent of cardiorespiratory fitness levels. [ABSTRACT FROM AUTHOR]

Purpose: We assessed the validity of predicting peak oxygen uptake ( $$ {\dot{V}} $$ O peak) from the relationship between oxygen uptake ( $$ {\dot{V}} $$ O) and overall ratings of perceived exertion (RPE) obtained during the initial stages of a cardiopulmonary exercise test (CPET). Method: Fifteen healthy participants and 18 patients with chronic obstructive pulmonary disease (COPD) performed a maximal CPET, during which $$ {\dot{V}} $$ O and RPE were measured until RPE. Results: Individual regressions between $$ {\dot{V}} $$ O and RPE were extrapolated to RPE to predict $$ {\dot{V}} $$ O peak. Mean actual and predicted $$ {\dot{V}} $$ O peak were not significantly different in healthy women (18.9 ± 4.1 vs. 20.4 ± 4.5 mL kg min, respectively) and men (28.9 ± 7.8 vs. 29.7 ± 8.5 mL kg min, respectively), or in women (15.2 ± 4.7 vs. 15.8 ± 5.0 mL kg min, respectively) and men (16.2 ± 4.4 vs. 17.4 ± 5.4 mL kg min, respectively) with COPD ( P = 0.067). Moreover, actual and predicted $$ {\dot{V}} $$ O peak were highly correlated in healthy participants and COPD patients ( r ≥ 0.89; P < 0.001). The bias and 95 % limits of agreement were −1.0 ± 4.0 and −1.0 ± 4.6 mL kg min for healthy and COPD participants, respectively. Conclusion: $$ {\dot{V}} $$ O peak can be predicted with acceptable accuracy in healthy participants and patients with COPD from the individual relationship between $$ {\dot{V}} $$ O and RPE. [ABSTRACT FROM AUTHOR]

Purpose: An acute reduction in blood pressure observed after a single bout of exercise is termed post-exercise hypotension (PEH). In contrast to moderate intensity aerobic exercise, little is known about the PEH response following high-intensity interval exercise. The present purpose is to assess how sex and training status impact PEH following high-intensity interval exercise. Methods: Cardiac volumes and function via echocardiography were measured in 40 normotensive, endurance-trained (ET) and normally active (NA) men and women (Age ± SD = 30.5 ± 5.7) following high-intensity interval cycle exercise. Continuous measurements of ECG and beat-by-beat blood pressure were collected before and 30 min post-exercise for determination of cardiovagal baroreflex function (BRS and αLF), spectral analysis of heart rate and systolic blood pressure (SBP LF). Results: Post-exercise systolic BP was significantly reduced from baseline, occurring to a greater degree in ET compared with NA (−12.9 vs. −5.3 mmHg, P = 0.008), while mean arterial pressure was similarly reduced in all groups (−4.6 mmHg, P = 0.003). Despite reduced SVI and TPRI, CI was increased post-exercise ( P < 0.01). ET experienced a greater decrease in αLF ( P = 0.037) and increase in SBP LF ( P = 0.017) than NA. Lean body mass was a significant predictor of change in SBP LF (Std. β = 0.735, P = 0.008). Conclusions: These results characterize greater depressions in cardiovagal baroreflex function, and increased sympathetic activity, following vigorous exercise in endurance-trained individuals compared with normally active participants. This heightened sympathovagal balance after high-intensity exercise may be a compensatory mechanism in response to greater peripheral blood flow demands following vigorous exercise. [ABSTRACT FROM AUTHOR]

Purpose: To test the validity and reliability of field critical power (CP). Method: Laboratory CP tests comprised three exhaustive trials at intensities of 80, 100 and 105 % maximal aerobic power and CP results were compared with those determined from the field. Experiment 1: cyclists performed three CP field tests which comprised maximal efforts of 12, 7 and 3 min with a 30 min recovery between efforts. Experiment 2: cyclists performed 3 × 3, 3 × 7 and 3 × 12 min individual maximal efforts in a randomised order in the field. Experiment 3: the highest 3, 7 and 12 min power outputs were extracted from field training and racing data. Results: Standard error of the estimate of CP was 4.5, 5.8 and 5.2 % for experiments 1-3, respectively. Limits of agreement for CP were −26 to 29, 26 to 53 and −34 to 44 W for experiments 1-3, respectively. Mean coefficient of variation in field CP was 2.4, 6.5 and 3.5 % for experiments 1-3, respectively. Intraclass correlation coefficients of the three repeated trials for CP were 0.99, 0.96 and 0.99 for experiments 1-3, respectively. Conclusions: Results suggest field-testing using the different protocols from this research study, produce both valid and reliable CP values. [ABSTRACT FROM AUTHOR]

Purpose: Many endurance athletes complain about gastrointestinal (GI) symptoms. It is assumed that exercise-induced shift of perfusion with consecutive hypoperfusion of the enteral vascular system leads to an increased GI permeability and tissue damage. Therefore, the aim of the study was to investigate permeability, apoptosis, electrogenic ion transport (Isc), and tissue conductance (Gt) of the small intestine in a murine exercise model. Methods: After spirometry, male Swiss CD-1 mice were subjected to an intensive treadmill exercise (80 % VO). Sedentary mice served as controls. The small intestine was removed at several time intervals post-exercise. Apoptotic cells were determined by the TUNEL method, while fluorescein isothiocyanate dextran permeation indicated intestinal permeability. The Gt and Isc measurements were carried out in a modified Ussing chamber. Results: Apoptosis of epithelial cells increased continuously until 24 h post exercise (0.8 ± 0.42 versus 39.2 ± 26.0 %; p < 0.05). Compared with the control group the permeability increased 2 h after exercise (0.47 ± 0.07 versus 0.67 ± 0.14 FU/min; p < 0.05). Isc measurements of the ileum were augmented after 24 h (3.33 ± 0.56 versus 5.77 ± 1.16 μEq/h/cm; p < 0.05). At this time the Gt increased as well (28.8 ± 3.37 versus 32.5 ± 2.59 mS/cm; p < 0.05). Conclusion: In the murine exercise model there is evidence that after intense endurance exercise repair processes occur in small intestinal epithelial cells, which affect permeability, Gt, and Isc. The formation of lamellipodia to close the 'leaky' tight junctions caused by apoptosis might be an underlying mechanism. [ABSTRACT FROM AUTHOR]

Purpose: Short-to-moderate duration exercise training improves fitness and lowers cardiovascular risk in type 2 diabetes (T2DM). However, the impact of long-term compliance to an active lifestyle of T2DM patients on cardiovascular risk factors has never been studied but could provide information on the maximal achievable health effect of physical activity in T2DM. This study examined the impact of a life-long active lifestyle by comparing physical fitness, cardiovascular risk and vascular function between long-term physically active T2DM patients versus sedentary T2DM patients and controls. Methods: Fitness, HOMA-IR, brachial artery flow-mediated dilation (FMD) and lifetime risk for cardiovascular disease were assessed in 15 exercising T2DM patients, 12 age-, sex- and weight-matched sedentary T2DM patients and 9 sedentary men free of established cardiovascular and metabolic disease as controls. Long-term regular exercise was defined as self-reported participation of >2.5 h of (predominantly) endurance exercise per week, which was performed for 18-47 years. Results: Sedentary T2DM patients showed lower fitness (21.8 ± 2.3, 32.6 ± 6.0 and 31.1 ± 3.2 ml O/kg/min), higher HOMA-IR (8.3 ± 5.0, 2.0 ± 1.8 and 1.1 ± 0.5 100/%S) and higher lifetime risk scores (17.3 ± 5.4, 9.3 ± 5.0 and 8.9 ± 3.9 %) compared to active peers and controls, respectively. Brachial artery FMD was lower in sedentary T2DM patients compared with active peers, but not in controls (3.3 ± 1.2, 5.2 ± 2.1 and 3.8 ± 1.2 %). Conclusions: Life-long active T2DM patients have superior fitness levels, HOMA-IR, cardiovascular risk and FMD compared to sedentary peers, whilst no differences were found when compared to controls. This study provides evidence that a life-long active lifestyle, even in T2DM, may be able to effectively normalize cardiovascular risk. [ABSTRACT FROM AUTHOR]

Purpose: Injury prevention effects of neuromuscular training have been partly attributed to postural control adaptations. Uncertainty exists regarding the magnitude of these adaptations and on how they can be adequately monitored. The objective was to determine the time course of neuromuscular training effects on functional, dynamic and static balance measures. Methods: Thirty youth (14.9 ± 3 years) field hockey athletes were randomised to an intervention or control group. The intervention included a 20-min neuromuscular warm-up program performed twice weekly for 10 weeks. Balance assessments were performed at baseline, week three, week six and post-intervention. They included the star excursion balance test (SEBT), balance error scoring system (BESS), jump-landing time to stabilization (TTS) and center of pressure (COP) sway velocity during single-leg standing. Results: No baseline differences were found between groups in demographic data and balance measures. Adherence was at 86 %. All balance measures except the medial-lateral TTS improved significantly over time ( p < 0.05) in both groups. Significant group by time interactions were found for the BESS score ( p < 0.001). The intervention group showed greater improvements (69.3 ± 10.3 %) after 10 weeks in comparison to controls (31.8 ± 22.1 %). There were no significant group by time interactions in the SEBT, TTS and COP sway velocity. Conclusions: Neuromuscular training was effective in improving postural control in youth team athletes. However, this effect was not reflected in all balance measures suggesting that the neuromuscular training did not influence all dimensions of postural control. Further studies are needed to confirm the potential of specific warm-up programs to improve postural control. [ABSTRACT FROM AUTHOR]

Purpose: This study examined the effects of short-term high-intensity interval training (HIT) and continuous moderate-intensity training (CMT) on cardiac function in young, healthy men. Methods: Sixteen previously untrained men (mean age of 25.1 ± 4.1 years) were randomly assigned to HIT and CMT ( n = 8 each) and assessed before and after six sessions over a 12-day training period. HIT consisted of 8-12 intervals of cycling for 60 s at 95-100 % of pre-training maximal aerobic power ( $$\dot{V}$$ O), interspersed by 75 s of cycling at 10 % $$\dot{V}$$ O. CMT involved 90-120 min of cycling at 65 % pre-training $$\dot{V}$$ O. Left ventricular (LV) function was determined at rest and during submaximal exercise (heart rate ~105 bpm) using two-dimensional and Doppler echocardiography. Results: Training resulted in increased calculated plasma volume (PV) in both groups, accompanied by improved $$\dot{V}$$ O in HIT (HIT: from 39.5 ± 7.1 to 43.9 ± 5.5 mL kg min; CMT: from 39.9 ± 5.9 to 41.7 ± 5.3 mL kg min; P < 0.001). Resting LV function was not altered. However, increased exercise stroke volume ( P = 0.02) and cardiac output ( P = 0.02) were observed, secondary to increases in end-diastolic volume ( P < 0.001). Numerous Doppler and speckle tracking indices of diastolic function were similarly enhanced during exercise in both training groups and were related to changes in PV. Conclusion: Short-term HIT and CMT elicit rapid improvements in $$\dot{V}$$ O and LV filling without global changes in cardiac performance at rest. [ABSTRACT FROM AUTHOR]

Modern international military deployments in austere environments (i.e., Iraq and Afghanistan) place considerable physiological demands on soldiers. Significant physiological challenges exist: maintenance of physical fitness and body composition, rigors of external load carriage, environmental extremes (heat, cold, and altitude), medical illnesses, musculoskeletal injuries, traumatic brain injuries, post-traumatic stress disorder, and environmental exposure hazards (i.e., burn pits, vehicle exhaust, etc.). To date there is very little published research and no comprehensive reviews on the physiological effects of deployments. The purpose of this paper is to overview what is currently known from the literature related mainly to current military conflicts with regard to the challenges and consequences from deployments. Summary findings include: (1) aerobic capacity declines while muscle strength, power and muscular endurance appear to be maintained, (2) load carriage continues to tax the physical capacities of the Soldier, (3) musculoskeletal injuries comprise the highest proportion of all injury categories, (4) environmental insults occur from both terrestrial extremes and pollutant exposure, and (5) post-deployment concerns linger for traumatic brain injury and post-traumatic stress disorder. A full understanding of these responses will assist in identifying the most effective risk mitigation strategies to ensure deployment readiness and to assist in establishment of military employment standards. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the present study was to test the hypotheses that a greater oxidative capacity in children results in a lower phosphocreatine (PCr) depletion, a faster PCr resynthesis and a lower muscle acidification during high-intensity intermittent exercise compared to adults. Methods: Sixteen children (9.4 ± 0.5 years) and 16 adults (26.1 ± 0.3 years) completed a protocol consisting of a dynamic plantar flexion (10 bouts of 30-s exercise at 25 % of one repetition maximum separated by 20-s recovery), followed by 10 min of passive recovery. Changes of PCr, ATP, inorganic phosphate, and phosphomonoesters were measured by means of Phosphorous-magnetic resonance spectroscopy during and post-exercise. Results: Average PCr (percentage of [PCr] at initial rest (%[PCr])) at the end of the exercise (adults 17 ± 12 %[PCr], children 38 ± 17 %[PCr], P < 0.01) and recovery periods (adults 37 ± 14 %[PCr], children 57 ± 17 %[PCr], P < 0.01) was significantly lower in adults compared to children, induced by a stronger PCr decrease during the first exercise interval (adults −73 ± 10 %[PCr], children −55 ± 15 %[PCr], P < 0.01). End-exercise pH was significantly higher in children compared to adults (children 6.90 + 0.20, −0.14; adults 6.67 + 0.23, −0.15, P < 0.05). Conclusions: From our results we suggest relatively higher rates of oxidative ATP formation in children's muscle for covering the ATP demand of high-intensity intermittent exercise compared to adults, enabling children to begin each exercise interval with significantly higher PCr concentrations and leading to an overall lower muscle acidification. [ABSTRACT FROM AUTHOR]

This paper examines the processes involved in the establishment of a minimum occupational fitness standard, with particular reference to the interplay that inevitably occurs between objective measurements and subjective decisions. The areas considered include: the determination of the critical task on which to base a standard; establishing minimum acceptable performance and methods of best practice for the execution of these tasks; determining the physical demands of a task and a reasonable relative workload; producing the final standard. Finally, the impact of the subjective component of the development of an occupational fitness standard on its defensibility is discussed. It is concluded that all standards involve some subjective aspects; the extent of these could be reduced by further research. In the meantime, it would be prudent for those developing standards to detail the rationale, methods and evidence by which subjective decisions were reached, to provide an audit trail for subsequent investigation. [ABSTRACT FROM AUTHOR]

This study examined the effect of 12 weeks of small-sided street soccer (2.2 ± 0.7 sessions/week) and fitness center training (0.5 ± 0.2 sessions/week) on physical fitness and cardiovascular health profile for homeless men. Exercise capacity, maximal oxygen uptake ( VO), body composition (DXA scans), blood pressure (BP), and blood lipid profile were determined before and after the intervention period for 22 soccer-group subjects (SG) and 10 waiting list controls (CO). In addition, time-motion analyses, HR measurements, and pedometer recordings were performed during street soccer training and daily-life activities. During a 60 min 4 versus 4 street soccer session 182 ± 62 intense running bouts were performed; mean HR was 82 ± 4% HR and HR was >90% HR for 21 ± 12% (±SD) of total time. On a day without training the participants performed 10,733 ± 4,341 steps and HR was >80% HR for 2.4 ± 4.3 min. In SG, VO was elevated ( p < 0.05) from 36.7 ± 7.6 to 40.6 ± 8.6 ml/min/kg after 12 weeks and incremental cycle test performance was improved ( p < 0.05) by 81 s (95% CI: 47-128 s). After 12 weeks, fat percentage (19.4 ± 8.5 to 17.5 ± 8.6%) and LDL cholesterol (3.2 ± 1.1 to 2.8 ± 0.8 mmol L) were lowered ( p < 0.05) in SG. The observed changes in SG were different ( p < 0.05) from CO and no intra-group changes occurred for CO ( p > 0.05). BP was unaltered after 12 weeks ( p > 0.05), but diastolic BP was lowered for all SG subjects with pre-values >75 mmHg (83 ± 6 to 76 ± 6 mmHg, n = 8, p < 0.05). In conclusion, the exercise intensity is high during street soccer and regular street soccer training can be used as an effective activity to promote physical fitness and cardiovascular health status for homeless men. [ABSTRACT FROM AUTHOR]

The aim was to investigate the effect of high-volume low intensity resistance training protocol combined with endurance training on plasma neuropeptide Y (NPY) concentration in rowers. Additionally, leptin and ghrelin, as markers for body energy balance concentrations, were monitored. 12 highly trained national and international level male rowers participated in this study. The participants were tested three times-after reference week (T1), after 2 weeks of high-volume training (T2) and after a recovery week (T3) for aerobic performance, energy intake and expenditure, and blood biochemical parameters. The submaximal rowing performance decreased significantly ( P = 0.019) at T2. Fasting leptin decreased significantly (from 2.05 ± 0.88 to 1.28 ± 0.53 ng/mL; P = 0.009) at T2 and increased significantly (from 1.28 ± 0.53 to 1.79 ± 0.79 ng/mL; P = 0.002) at T3. Fasting ghrelin decreased significantly (from 980 ± 300.2 to 873.35 ± 198.6 pg/mL; P = 0.036) at T3 compared to T2, while no changes were found in fasting NPY. Significant decreases in exercise-induced leptin were observed at T2 (from 1.13 ± 0.5 to 1.08 ± 0.5 ng/mL; P = 0.012), PRE and POST test leptin values at T2 were significantly decreased compared to T1(1.40 ± 0.9 to 1.13 ± 0.5 and 1.44 ± 0.8 to 1.08 ± 0.5, respectively). Acute exercise-induced increases in NPY were found at T2 (from 128.1 ± 23.2 to 155.1 ± 28.9 pmol/L; P = 0.002) and at T3 (from 131.3 ± 20.5 to 159.7 ± 32.8 pmol/L, P = 0.004). In conclusion, the combination of high-volume training protocol and energy imbalance induces significant post-exercise changes in NPY, leptin, and ghrelin concentrations and decreases fasting leptin. [ABSTRACT FROM AUTHOR]

The primary objective of this investigation was to quantitatively identify which training variables result in the greatest strength and hypertrophy outcomes with lower body low intensity training with blood flow restriction (LI-BFR). Searches were performed for published studies with certain criteria. First, the primary focus of the study must have compared the effects of low intensity endurance or resistance training alone to low intensity exercise with some form of blood flow restriction. Second, subject populations had to have similar baseline characteristics so that valid outcome measures could be made. Finally, outcome measures had to include at least one measure of muscle hypertrophy. All studies included in the analysis utilized MRI except for two which reported changes via ultrasound. The mean overall effect size (ES) for muscle strength for LI-BFR was 0.58 [95% CI: 0.40, 0.76], and 0.00 [95% CI: −0.18, 0.17] for low intensity training. The mean overall ES for muscle hypertrophy for LI-BFR training was 0.39 [95% CI: 0.35, 0.43], and −0.01 [95% CI: −0.05, 0.03] for low intensity training. Blood flow restriction resulted in significantly greater gains in strength and hypertrophy when performed with resistance training than with walking. In addition, performing LI-BFR 2-3 days per week resulted in the greatest ES compared to 4-5 days per week. Significant correlations were found between ES for strength development and weeks of duration, but not for muscle hypertrophy. This meta-analysis provides insight into the impact of different variables on muscular strength and hypertrophy to LI-BFR training. [ABSTRACT FROM AUTHOR]

Research into daily physical activity (PA) patterns of older adults (≥70 years) has primarily relied on self-report. This study used accelerometry, an objective measure of minute-by-minute movement, to assess PA volume and intensity performed by older adults recruited to the Better Ageing project. Results were used to estimate the degree to which current health recommendations for PA were met. Participants [91 older females (OF) aged 76.0 ± 4.0 years (mean ± SD), 70 older males (OM) 76.3 ± 3.9 years, 23 young females (YF) 26.8 ± 4.1 years and 22 young males (YM) 27.0 ± 4.2 years] wore an MTI actigraph model 7164 recording activity in 1-min epochs for 7 days. Only those with at least 5 days, and 10 h of actigraph data per day, were included in the analysis, using Caloric.Bas (CSA Inc. 1999) software and a tailored Microsoft Access 2000 macro. Mean counts min-1 day-1 were 37% lower for older adults than for young adults [OF 236.1 ± 84.4 vs. YF 370.0 ± 81.1 counts min-1 day-1 t(114) = −6.86, P < 0.001; OM 255.1 ± 103.0 vs. YM 404.3 ± 134.0 ct min-1 day-1, t(91) = −5.55, P < 0 .001]. Older adults were more restricted in activity intensity range performing significantly fewer minutes of moderate to vigorous (MV) PA day-1 than young adults [OF 16.7 ± 12.2 vs. YF 38.4 ± 18.4 MVPA min day-1, t(114) = −6.90, P < 0.001; OM 23.8 ± 20.0 vs. YM 40.4 ± 19.2 MVPA min day-1, t(91) = −3.47, P = 0.001]. Nearly half of older adults did not perform any sustained 10-min MVPA bouts (OF 48.4% vs. YF 13.0%, χ2 = 8.10, P = 0.004; OM 44.3% vs. YM 4.5%, χ 2 = 9.97, P = 0.002), and none met current PA recommendations for health. This study is the first to provide objective data on a large sample of adults aged 70 years and over and indicates low levels of daily movement that are likely to be inadequate for optimal health benefit. [ABSTRACT FROM AUTHOR]

Decreased steadiness of muscle force may be associated with ageing and could be a cause of falls in older people. We studied this in isometric and anisometric quadriceps contractions in healthy young and older people. The older group contained people with and without a history of medically unexplained falls. Forty-four young (aged 18–40 years) and 78 older (aged > 70 years) subjects participated. In the latter group 34 people had a history of falling (fallers) and 44 did not (non-fallers). Isometric steadiness was measured by the coefficient of variation (CoV) of force at 10, 25 and 50% maximal voluntary force (MVC). Anisometric steadiness was measured by the SD of acceleration during concentric and eccentric contractions against two external loads (1 and 5 kg). There was an overall trend for the younger subjects to be most steady and the fallers the least but the differences were not consistently significant. Isometric steadiness was unaffected by force in all groups. The fallers were less steady ( P < 0.001) than both the young and non-fallers, who had similar values. During anisometric contractions, steadiness was similar with both external loads and types of contraction in all groups. During dynamic contractions the older subjects were less steady ( P < 0.002). Only eccentric contractions distinguished between the two older groups, with the fallers being less steady by 31% ( P = 0.013). These data indicate ageing per se is associated with decreased anisometric, but not isometric, steadiness. Greater unsteadiness during eccentric contractions in the fallers could be an important mechanism of medically unexplained falls. [ABSTRACT FROM AUTHOR]

The impact of ageing on force and velocity of human skeletal muscle fibres has been extensively studied. As discrepancies have been reported, it is still unclear whether or not a deterioration of the capacity of muscle fibres to develop force and shortening is involved in determining weakness and decrease in shortening velocity of skeletal muscle of elderly people. We compared myosin heavy chain (MHC) isoform distribution of vastus lateralis muscle, and specific force ( Po/CSA) and maximum shortening velocity ( Vo) of skeletal muscle fibres among one population of young controls (CTRL) and three populations of elderly (EL) subjects with very variable levels of physical activity: sedentary (EL-SED, n = 3); controls (EL-CTRL, n = 4); endurance trained (EL-END, n = 3). Muscle phenotype was progressively faster in the order EL-END → CTRL → EL-CTRL → EL-SED. Po/CSA and Vo also varied among the different populations of elderly subjects generally showing a decreasing deterioration with increasing activity levels. The results suggest that discrepancies observed so far in age-induced deterioration of contractile properties of muscle fibres could depend on the different activity levels of the populations of elderly subjects enrolled in the studies. [ABSTRACT FROM AUTHOR]