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Prader-Willi Syndrome (PWS), the best characterized form of syndromic obesity, presents with abnormally high fat mass. In children, obesity presents with low-grade systemic inflammation. This study evaluated if PWS and/or nonsyndromic obesity affected cytokine responses to intermittent aerobic exercise in children. Eleven children with PWS (11 ± 2 y, 45.4 ± 9.5% body fat), 12 children with obesity (OB) (9 ± 1 y, 39.9 ± 6.8% body fat), and 12 lean (LN) children (9 ± 1 y, 17.5 ± 4.6% body fat) participated. Children completed 10 2-min cycling bouts of vigorous intensity, separated by 1-min rest. Blood samples were collected preexercise (PRE), immediately postexercise (IP), and 15, 30, and 60 min into recovery to analyze possible changes in cytokines. In all groups, IL-6 and IL-8 concentrations were greater during recovery compared with PRE. PWS and OB exhibited higher IL-6 area under the curve (AUC) than LN (p < .01 for both). PWS demonstrated higher IL-8 AUC than LN (p < .04). IL-10, TNF-α, and IFN-γ did not change with exercise (p > .05 for all). Results indicate that children with PWS respond with increased Il-6 and IL-8 concentrations to acute exercise similarly to controls. Excess adiposity and epigenetic modifications may explain the greater integrated IL-6 and IL-8 responses in PWS compared with controls. [ABSTRACT FROM AUTHOR]

During childhood, varying exercise modalities are recommended to stimulate normal growth, development, and health. This project investigated hormonal and metabolic responses triggered by a resistance exercise protocol in lean children (age: 9.3 ± 1.4 y, body fat: 18.3 ± 4.9%), obese children (age: 9.6 ± 1.3 y, body fat: 40.3 ± 5.2%) and lean adults (age: 23.3 ± 2.4 y, body fat: 12.7 ± 2.9%). The protocol consisted of stepping onto a raised platform (height = 20% of stature) while wearing a weighted vest (resistance = 50% of lean body mass). Participants completed 6 sets of 10 repetitions per leg with a 1-min rest period between sets. Blood samples were obtained at rest preexercise, immediately postexercise and 2 times throughout the 1-hr recovery to analyze possible changes in hormones and metabolites. Children-adult differences included a larger exercise-induced norepinephrine increase in adults vs. children and a decrease in glucagon in children but not adults. Similarities between adults and children were observed for GH-IGF-1 axis responses. Metabolically, children presented with lower glycolytic and increased fat metabolism after exercise than adults did. Obesity in childhood negatively influenced GH, insulin, and glucose concentrations. While adults occasionally differed from children, amount of activated lean mass, not maturation, likely drove these dissimilarities. [ABSTRACT FROM AUTHOR]

Context: Dieticians, physiologists, athletic trainers, and physicians have recommended refraining from caffeine intake when exercising because of possible fluid-electrolyte imbalances and dehydration. Objective: To assess how 16-hour rehydration is affected by caffeine ingestion. Design: Dose-response. Setting: Environmental chamber. Participants: 59 college-age men. Intervention: Sub-jects consumed a chronic caffeine dose of 0 (placebo), 3, or 6 mg · kg-1 · day-1 and performed an exercise heat-tolerance test (EHT) consisting of 90 minutes of walking on a treadmill (5.6 km/h) in the heat (37.7 °C). Outcome Measures: Fluid-electrolyte measures. Results: There were no between-group differences immediately after and 16 hours after EHT in total plasma protein, hematocrit, urine osmolality, specific gravity, color, and volume. Body weights after EHT and the following day (16 hours) were not different between groups (P > .05). Conclusion: Hydration status 16 hours after EHT did not change with chronic caffeine ingestion. [ABSTRACT FROM AUTHOR]

This investigation determined if 3 levels of controlled caffeine consumption affected fluid-electrolyte balance and renal function differently. Healthy males (mean ± standard deviation; age, 21.6 ± 3.3 y) consumed 3 mg caffeine · kg-1 · d-1 on days 1 to 6 (equilibration phase). On days 7 to 11 (treatment phase), subjects consumed either 0 mg (C0; placebo; n = 20), 3 mg (C3; n = 20), or 6 mg (C6; n = 19) caffeine · kg-1 · d-1 in capsules, with no other dietary caffeine intake. The following variables were unaffected (P > 0.05) by different caffeine doses on days 1, 3, 6, 9, and 11 and were within normal clinical ranges: body mass, urine osmolality, urine specific gravity, urine color, 24-h urine volume, 24-h Na+ and K+ excretion, 24-h creatinine, blood urea nitrogen, serum Na+ and K+, serum osmolality, hematocrit, and total plasma protein. Therefore, C0, C3, and C6 exhibited no evidence of hypohydration. These findings question the widely accepted notion that caffeine consumption acts chronically as a diuretic. [ABSTRACT FROM AUTHOR]

Background: Prader-Willi syndrome (PWS) is characterized by excessive adiposity. Excess adiposity negatively affects hormonal and metabolic responses to aerobic exercise. This study determined whether PWS and/or adiposity affected hormonal and metabolic responses to resistance exercise. Methods: Eleven children with PWS (11.4 ± 3.1 years, 43.9 ± 7.5% body fat), 12 lean children (9.3 ± 1.4 years, 18.3 ± 4.9% body fat), and 13 obese children (9.6 ± 1.3 years, 40.3 ± 5.2% body fat) participated. The children stepped onto an elevated platform while wearing a weighted vest for 6 sets of 10 repetitions per leg (sets separated by 1 min of rest). For the children with PWS, the platform height was 23.0 cm and vest load was computed as (20% of stature × 50% of lean body mass)/23.0 cm. For the controls, the platform height was 20% of the stature and vest load 50% of the lean body mass. Blood samples were obtained before, immediately after, and during recovery from exercise (+15, +30, and +60 min). Results: All groups had similar catecholamine, insulin, and glucagon responses. The groups showed no major differences in glucose and lactate levels. The PWS children demonstrated earlier increases in fatty acids during recovery and higher glycerol and ketone levels than the controls. Conclusion: The PWS children demonstrated largely intact hormonal, glycolytic, and lipolytic responses to lower-body resistance exercise. In PWS, elevated ketone levels suggest an incomplete fat oxidation. [ABSTRACT FROM AUTHOR]

Laboratory-based studies indicate mild dehydration adversely affects mood. Although ultra-endurance events often result in mild to moderate dehydration, little research has evaluated whether the relationship between hydration status and mood state also exists in these arduous events. Therefore, the purpose of this study was to evaluate how hydration status affected mood state and perceptual measures during a 161 km ultra-endurance cycling event. One hundred and nineteen cyclists (103 males, 16 females; age = 46 ± 9 years; height = 175.4 ± 17.9 cm; mass = 82.8 ± 16.3 kg) from the 2011 and 2013 Hotter’N Hell events participated. Perceived exertion, Thermal, Thirst, and Pain sensations, Brunel Profile of Mood States, and urine specific gravity (USG) were measured pre- (~1 h before), mid- (~97 km), and post-ride. Participants were classified at each time point as dehydrated (USG ≥ 1.022) or euhydrated (USG ≤ 1.018). Independent of time point, dehydrated participants (USG = 1.027 ± 0.004) had decreased Vigour and increased Fatigue, Pain, Thirst, and Thermal sensations compared to euhydrated participants (USG = 1.012 ± 0.004; allP < 0.01). USG significantly correlated with Fatigue (r = 0.36), Vigour (r = −0.27), Thirst (r = 0.15), and Pain (r = 0.22; allP < 0.05). In conclusion, dehydrated participants had greater Fatigue and Pain than euhydrated participants. These findings indicate dehydration may adversely affect mood state and perceptual ratings during ultra-endurance cycling. [ABSTRACT FROM AUTHOR]

Purpose: Resistance exercise induces a host of endocrine responses that potentiate its effects on body composition and metabolism. Excess adiposity negatively affects some hormonal responses to exercise in sedentary men. This study compared the resistance exercise (RE)-associated growth hormone (GH), insulin-like growth factor-1 (IGF-1), and testosterone responses in lean vs. obese physically active men. Methods: Ten healthy physically active obese males (body fat % 36.2 ± 4.03, age 24.6 ± 3.7 years, mass 104.5 ± 15.5 kg, height 178.8 ± 6.0 cm) were compared to ten lean counterparts (body fat % 12.7 ± 2.9, age 24.6 ± 3.7 years, mass 77.1 ± 6.4 kg, height 177.2 ± 4.8 cm). The muscular endurance RE protocol consisted of six sets of ten repetitions per leg of stepping onto an elevated platform (20 % of participant's height) while wearing a weighted-vest (50 % of participant's lean mass). Pre-, immediately post-exercise (IP), and three more blood samples were collected during the one-hour recovery. Results: When accounting for baseline differences there were no group by time interactions for GH ( p = 0.33); or LH ( p = 0.52). Lean presented a trend towards significance for higher IGF-1 IP ( p = 0.08) than obese. Testosterone IP was similar in obese and lean, but lower in obese than lean at 30 min into recovery ( p < 0.01). AUC were lower in obese than lean for all hormones ( p < 0.05 for all). Conclusion: These findings suggest that excess adiposity does not appear to negatively affect the immediate GH and T responses to RE in active males; but possibly negatively affects IGF-1. However, the baseline and integrated concentrations during recovery appear negatively affected by excess adiposity. [ABSTRACT FROM AUTHOR]

The article discusses research which investigated the effects caffeine had on strength and muscle activation of the elbow flexors. Researchers evaluated 13 recreationally active male volunteers who consumed a drink which either contained caffeine or did not and then performed isometric elbow exercises. They found that ingesting caffeine did not provide an ergogenic effect for the elbow flexors during isometric muscle actions.

Because body mass change (ΔMb) does not represent all water losses and gains, the present field investigation determined if (a) ΔMbequalled the net effective body water change during ultra-endurance exercise and (b) ground speed and exercise duration influenced these variables. Thirty-two male cyclists (age range, 35–52 years) completed a 164-km event in a hot environment, were retrospectively triplet matched and placed into one of three groups based on exercise duration (4.8, 6.3, 9.6 h). Net effective body water loss was computed from measurements (body mass, total fluid intake and urine excreted) and calculations (water evolved and mass loss due to substrate oxidation, solid food mass and sweat loss), including (ΔEBWgly) and excluding (ΔEBW) water bound to glycogen. With all cyclists combined, the mean ΔMb(i.e. loss) was greater than that of ΔEBWglyby 1200 ± 200 g (P= 1.4 × 10–18), was similar to ΔEBW (difference, 0 ± 200 g;P= .21) and was strongly correlated with both (R2= .98). Analysis of equivalence indicated that ΔMbwas not equivalent to ΔEBWgly, but was equivalent to ΔEBW. Due to measurement complexity, we concluded that (a) athletes will not calculate the effective body water calculations routinely and (b) body mass change remains a useful field-expedient estimate of net effective body water change. [ABSTRACT FROM AUTHOR]

The article discusses research which was conducted to investigate the effect of cluster sets and traditional sets on plyometric jump power (PW), ground reaction force, take-off velocity (TOV), and jump height (JH). Researchers evaluated 26 college men. They found that cluster sets allowed for greater maintenance of PW, TOV, and JH than traditional training sets.

Context: The sensation of thirst is different from the complex behavior of drinking ad libitum. Rehydration recommendations to athletes differ, depending on the source, yet no previous researchers have systematically compared drinking to thirst (DTT) versus ad libitum drinking behavior (DAL). Objective: To compare 2 groups of trained cyclists (DTT and DAL) who had similar physical characteristics and training programs (P > .05). The DTT group (n = 12, age = 47 6 7 years) drank only when thirsty, whereas the DAL group (n = 12, age = 44 6 7 years) consumed fluid ad libitum (ie, whenever and in whatever volume desired). Design: Cohort study. Setting: Road cycling (164 km) in the heat (36.18C ± 6.58C). Patients or Other Participants: Ultraendurance cyclists (4 women, 20 men). Intervention(s): We recorded measurements 1 day before the event, on event day before the start, at 3 roadside aid stations, at the finish line, and 1 day after the event. Main Outcome Measure(s): Body mass, urinary hydration indices, and food and fluids consumed. Results: No between-groups differences were seen on event day for total exercise time (DTT = 6.69 6 0.89 hours, DAL = 6.66 6 0.77 hours), urinary indices (specific gravity, color), body mass change (DTT = -2.22% 6 1.73%, DAL = -2.29% 6 1.62%), fluid intake (DTT=5.63 6 2.59 L/6.7 h, DAL= 6.04 6 2.37 L/6.7 h), dietary energy intake, macronutrient intake, ratings of thirst (DTT start=2 ± 1, DTT finish=6 ± 1, DAL start = 2 ± 1, DAL finish = 6 6 1), pain, perceived exertion, or thermal sensation. Total fluid intake on recovery dayþ1 was the primary significant difference (DAL = 5.13 ± 1.87 L/24 h, DTT = 3.13 6 1.53 L/24 h, t18 = 2.59, P = .02). Conclusions: Observations on event day indicated that drinking to thirst and drinking ad libitum resulted in similar physiologic and perceptual outcomes. This suggests that specific instructions to "drink to thirst" were unnecessary. Indeed, if athletes drink ad libitum, they can focus on training and competition rather than being distracted by ongoing evaluation of thirst sensations. [ABSTRACT FROM AUTHOR]

The article reports on research which was conducted to investigate the effects a single bout of lower body exercise had on muscle activation and performance during subsequent lower and upper body resistance exercise workouts. Researchers evaluated 14 men who used an eliptical machine for lower body aerobic exercise. They concluded that the areobic exercise did not impact the subsequent workouts.

The article reports on research which was conducted to investigate the effects different exercise recovery interventions had on strength, electromyographic and mechanomyographic signals in ten recreationally trained male college students who performed isokinetic leg extensions. Researchers evaluated the athletes, who particpated in either passive, active, passive diverting or active diverting interventions. They found that passive, active, passive diverting, and active diverting provide the same extent of recovery.

Aim: To compare body composition in children with Prader-Willi syndrome (PWS) not naïve to growth hormone (GH) with obese and lean controls. Methods: Participants included 12 children with PWS, 12 children with obesity (body fat percentage >95th percentile for age and sex) and 12 lean children (body fat percentage <85th percentile for age and sex) matched by age and height. Fat mass, lean mass, bone mineral content (BMC), bone mineral density (BMD) and BMD z-score for total body, hips and lumbar spine were obtained through dual X-ray absorptiometry. Results: PWS had higher fat percentage in the legs (p = 0.04) but similar leg fat mass (p = 1.00) compared to obese. PWS exhibited lower lean mass in the body (p = 0.04) and legs (p = 0.02) than obese, but similar to lean (p = 1.00 and p = 0.89, respectively). PWS had lower hip BMC (p < 0.01), BMD (p < 0.01) and BMD z-score (p < 0.01) compared to obese but similar to lean. No other differences were found between PWS and obese (p > 0.05 for all). Conclusions: Children with PWS not naïve to GH present differences in fat and lean mass distribution compared to obese controls. BMC and BMD appear unaffected by PWS, except at the hips. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The article reports on research which was conducted to investigate the attitudes that certified physical fitness trainers and athletic coaches had about the nomenclature of resistance training exercises. Researchers interviewed 205 subjects. They found that there was a need to establish consistent naming pattern guidelines for resistance training exercises. They concluded that a consistent naming pattern could provide direction and clarity for coaches and trainers.

Heart rate recovery (HRR) is an indicator of all-cause mortality in children and adults. We aimed to determine the effect of adiposity and Prader-Willi Syndrome (PWS), a congenital form of obesity, on HRR. Sixteen children of normal weight (NW = body fat % ≤85th percentile, 9.4 ± 1.1 y), 18 children with obesity (OB = body fat% >95th percentile, 9.3 ± 1.1 y), and 11 PWS youth (regardless of body fat %; 11.4 ± 2.5 y) completed peak and submaximal bike tests on separate visits. HRR was recorded one minute following peak and submaximal exercises. All groups displayed similar HRR from peak exercise, while NW (54 ± 16 beats) and OB (50 ± 12 beats) exhibited a significantly faster HRR from submaximal exercise than PWS (37 ± 14 beats).These data suggest that excess adiposity does not influence HRR in children, but other factors such as low cardiovascular fitness and/or autonomic dysfunction might be more influential. [ABSTRACT FROM AUTHOR]

The article reports on research conducted to investigate the effects self selected music (SSM) and no music (NM) had on the mood and performance of athletes performing bench presses and squat jumps. Researchers evaluated 20 resistance trained college males. They found that there was increased performance during an explosive exercise and an altered mood state when listening to SSM and that listening to SSM might be beneficial for acute power performance.

The article reports on research which investigated the impact warm-up routines had on peak torque, rate of torque development and the electromyographic and mechanomyographic signals of 29 male subjects. Researchers found that while warm up did not affect any of the factors which they investigated it did increase the amplitude of mechanomyographic signals.

The article presents a study which compared the potentiating effects of a depth jump versus a box-jump warm-up on vertical jump performance. Eight collegiate and nine club female volleyball players participated in the three-day testing that revealed a post-test decrease in all variables, with the failure to create a potentiating effect attributed to prolonged rest time or low intensity. The researchers noted that outcomes may be due to differences in individual optimal warm-up.

The article presents a study on the sprint running ability of collegiate women soccer players, which is used in evaluating the athletic potential of athletes. Methods used include electronic timing system, statistical analysis, and interclass correlation coefficient (ICC). Result shows that 30% of body weight assistance (BWA) with elastic cord helps in decreasing the sprint times in distance of 15 yards (yd).

Marttinen, RHJ, Judelson, DA, Wiersma, LD, and Coburn, JW. Effects of self-selected mass loss on performance and mood in collegiate wrestlers. J Strength Cond Res 25(4): 1010-1015, 2011-Wrestlers abruptly lose body mass before competition; however, the effects of 'weight cutting' are poorly understood because of conflicting evidence. This study aimed to determine the effects of self-selected mass loss on precompetition mood, grip strength, and lower body power in collegiate wrestlers. Sixteen male collegiate wrestlers (age = 20 ± 2 years, height = 177.5 ± 7.2 cm) were weighed 10 days before (D-10) a competitive meet. Euhydrated subjects were administered the Brunel Mood Scale (BRUMS), tested on grip strength, and given a 30-second Wingate Anaerobic Power test to determine lower body power. Additional weigh-ins were conducted 6 (D-6) and 2 (D-2) days before competition. Subjects repeated the testing battery the day of competition (D-0). During the study, wrestlers self-selected the method and timing of mass loss. Wrestlers lost 0.0-8.1% of their body mass using exercise, caloric restriction, or fluid deprivation. Most mass loss occurred between D-2 and D-0 (mean ± SD, D-10 = 81.7 ± 18.2 kg, D-6 = 81.2 ± 17.8 kg, D-2 = 81.1 ± 18.5 kg, D-0 = 79.0 ± 19.2 kg). Wrestlers losing >=4% body mass became significantly more confused (D-10 = 0 ± 0, D-0 = 3 ± 3); subjects losing less mass showed no difference in confusion. No significant differences existed across time for remaining BRUMS variables, grip strength, and Wingate variables. These results suggest that wrestlers self-select large, rapid mass loss that impairs aspects of psychological functioning without affecting grip strength or lower-body power. [ABSTRACT FROM AUTHOR]

The article describes a study that evaluated the effects of a self-selected mass loss practice known as weight cutting on the performance capabilities and moods of collegiate wrestlers. A group of male collegiate wrestlers near the age of 20 were examined in terms of precompetition mood, grip strength, and lower body strength.

The article discusses research that was conducted to investigate the effect that four different starting stances had on sprint times in collegiate volleyball players. Researchers evaluated 26 male and female players. They found that starting with a staggered stance produced the greatest sprinting velocity over the initial 15 feet of the sprint.

The article reports on research conducted to investigate the effects a stable surface (bench) vs. an unstable surface (Swiss ball) had on muscle activation when performing the dumbbell chest press and shoulder press. Researchers evaluated 16 healthy men. They found that there were no significant differences in muscle activation between surface types for either exercise.

The article reports on research conducted to compare muscle activation of the anterior deltoid, medial deltoid, and pectoralis major during a Smith machine and free weight bench press at lower {70% 1 repetition maximum (1RM)) and higher (90% 1RM) intensities. Researchers found that there was greater activation of the medial deltoid on the free weight bench press than on the Smith machine bench press and that there was greater muscle activation at the 90% 1 RM load than at the 70% 1 RM load.

The article reports on research conducted to investigate the effect of recovery duration after a potentiating stimulus on muscular power in recreationally trained individuals. Researchers evaluated 12 healthy male subjects. They found that although recovery duration failed to influence performance after a heavy-load exercise in recreationally trained individuals, discrepancies in individual strength might have influenced the time subjects potentiated.

The article reports on research conducted to investigate the effect high-force back squat volume had on vertical jump (VJ) height, ground reaction force (GRF), impulse (IMP), and takeoff velocity (TOV) in recreationally trained men. Researchers evaluated 16 recreationally trained men. They found that one repetition maximum back squat volume assignments do not produce a VJ potentiation response in recreationally trained men.

The article reports on the results of research which was conducted in an effort to determine the effect delayed-onset muscle soreness had on elbow flexion strength and the rate of velocity development in 19 male college students. Researchers found that muscle damage may cause significant decreases in elbow flexion concentric strength and rate of velocity development even if delayed-onset muscle soreness remains elevated.

The article reports on the study that examines the combined effect of hydration state and resistance exercise on markers of muscle damage. The study found that hypohydration did not enhance muscle damage following the resistance exercise challenge. It suggests athletes to commence exercise in a euhydrated state to maximize endogenous hormonal, metabolic, and mechanical benefits.

Hypohydration (decreased total body water) exacerbates the catabolic hormonal response to endurance exercise with unclear effects on anabolic hormones. Limited research exists that evaluates the effect of hypohydration on endocrine responses to resistance exercise; this work merits attention as the acute postexercise hormonal environment potently modulates resistance training adaptations. The purpose of this study was to examine the effect of hydration state on the endocrine and metabolic responses to resistance exercise. Seven healthy resistance-trained men (age = 23 ± 4 yr, body mass = 87.8 ± 6.8 kg, body fat = 11.5 ± 5.2%) completed three identical resistance exercise bouts in different hydration states: euhydrated (EU), hypohydrated by ∼-2.5% body mass (HY25), and hypohydrated by ∼5.0% body mass (HY50). Investigators manipulated hydration status via controlled water deprivation and exercise-heat stress. Cortisol, epinephrine, norepinephrine, testosterone, growth hormone, insulin-like growth factor-I, insulin, glucose, lactate, glycerol, and free fatty acids were measured during euhydrated rest, immediately preceding resistance exercise, immediately postexercise, and during 60 mm of recovery. Body mass decreased 0.2 ± 0.4, 2.4 ± 0.4, and 4.8 ± 0.4% during EU, HY25, and HY50, respectively, supported by humoral and urinary changes that clearly indicated subjects achieved three distinct hydration states. Hypohydration significantly 1) increased circulating concentrations of cortisol and norepinephrine, 2) attenuated the testosterone response to exercise, and 3) altered carbohydrate and lipid metabolism. These results suggest that hypohydration can modify the hormonal and metabolic response to resistance exercise, influencing the postexercise circulatory milieu. [ABSTRACT FROM AUTHOR]

The article reports that few caffeine studies have been published which include cognitive and physiologic considerations for the athlete. Lower doses of caffeine can be as effective as higher doses during exercise performance without any negative coincidence. Caffeine can improve the cognitive aspects of performance when an athlete has not slept well.

Significant scientific evidence documents the deleterious effects of hypohydration (reduced total body water) on endurance exercise performance; however, the influence of hypohydration on muscular strength, power and high-intensity endurance (maximal activities lasting >30 seconds but <2 minutes) is poorly understood due to the inconsistent results produced by previous investigations. Several subtle methodological choices that exacerbate or attenuate the apparent effects of hypohydration explain much of this variability. After accounting for these factors, hypohydration appears to consistently attenuate strength (by ≈2%), power (by ≈3%) and high-intensity endurance (by ∼10%), suggesting alterations in total body water affect some aspect of force generation. Unfortunately, the relationships between performance decrement and crucial variables such as mode, degree and rate of water loss remain unclear due to a lack of suitably uninfluenced data. The physiological demands of strength, power and high-intensity endurance couple with a lack of scientific support to argue against previous hypotheses that suggest alterations in cardiovascular, metabolic and/or buffering function represent the performance-reducing mechanism of hypohydration. On the other hand, hypohydration might directly affect some component of the neuromuscular system, but this possibility awaits thorough evaluation. A critical review of the available literature suggests hypohydration limits strength, power and high-intensity endurance and, therefore, is an important factor to consider when attempting to maximise muscular performance in athletic, military and industrial settings. [ABSTRACT FROM AUTHOR]

Few data exist on the temporal relationship between catecholamines and muscle force production in vivo. The purpose of this study was to examine the influence of preexercise arousal on sympathoadrenal neurohormones on muscular force expression during resistance exercise. Ten resistance-trained men completed two experimental conditions separated by 7 days: 1) acute heavy resistance exercise protocol (AHREP; 6 × 10 repetitions parallel squats, 80% 1 repetition maximum) and 2) control (Cont; rest). Peak force (Fpeak) was recorded during a maximal isometric squat preceding each set and mean force (Fmean) was measured during each set. Serial venous blood samples were collected before the AHREP and immediately preceding each set. Blood collection times were matched during Cont. Preexercise epinephrine (Epi), norepinephrine (NE), and dopamine (DA) increased (P ≤ 0.05) above Cont by 270, 255, and 164%, respectively. During exercise, Epi, NE, and DA continued to increase by 512, 271, and 38%, respectively, above preexercise values. Fpeak and Fmean decreased by ∼20–25% over the course of the AHREP. Post hoc data analysis revealed that five subjects (Fmaintainers) showed no decline (P ≥ 0.05) in muscular performance (Fpeak, Fmean) during AHREP and that five subjects (Freducers) had significant reductions in Fpeak and Fmean. Integrated area under the curve for Epi, NE, and Fpeak were greater (P < 0.02) for Fmaintainers than Freducers. In conclusion, an anticipatory rise in catecholamines existed, which may be essential for optimal force production at the onset of exercise. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine changes in body composition (BC) and physical performance tests (PT) resulting from a competitive season in soccer. Twenty-five male collegiate players (age = 19.9 ± 1.3 years; height = 177.6 ± 6.4 cm; body mass = 77.6 ± 8.6 kg, and percentage body fat = 12.8 ± 5.2%) were tested before (PRE) and after (POST) the 2003-2004 National Collegiate Athletic Association season. The following tests were performed: BC (anthropometric and dual energy x-ray absorptiometry measurements), vertical jump (VJ), 9.1-m (9 m) and 36.5-m (36 m) sprint, lower-body power (LP), total body power (TP), and cardiorespiratory endurance (O2max). Training was divided into soccer-specific training: field warm-up drills, practices, games, and additional conditioning sessions. A daily, unplanned, nonlinear periodization model was used to assign session volume and intensity for strength sessions (total repetitions ≤96 and workload was ≥80% of 1 repetition maximum). For the entire team, body mass significantly increased by 1.5 ± 0.4 kg from PRE to POST due to a significant increase in total lean tissue (0.9 ± 0.2 kg). Regionally, lean tissue mass significantly increased in the legs (0.4 ± 0.0 kg) and trunk (0.3 ± 0.1 kg). Physical performance variables were very similar for the entire team at PRE and POST; VJ (cm) = 61.9 ± 7.1 PRE vs. 63.3 ± 8.0 POST, 9.1-m (s) = 1.7 ± 0.1 PRE and POST, 36.5-m (s) = 5.0 ± 0.2 PRE and POST, predicted O2max (ml·kg·min-1)= 59.8 ± 3.3 PRE vs. 60.9 ± 3.4 POST. The only significant improvements across the season were for TP (17.3%) and for LP (10.7%). In conclusion, soccer athletes who begin a season with a high level of fitness can maintain, and in some cases improve, body composition and physical performance from before to after a competitive season. A correct combination of soccer-specific practices and strength and conditioning programs can maintain and develop physical performance, allowing a soccer athlete to perform optimally throughout pre-, in-, and postseason play. [ABSTRACT FROM AUTHOR]

This investigation evaluated the new National Collegiate Athletic Association model of heat acclimatization for football players using physiological, psychological, fluid balance, anthropometric, and nutritional variables. Eleven football players (20 ± 1 year, 1.88 ± 0.05 m, and 115.36 ± 18.85 kg) from a Division I football team were observed for the first 8 days of preseason practices. Measurements such as heart rate and gastrointestinal temperature (TGI) via telemetric sensor were taken before, 3 times during, and after practice daily. An average 1.39-kg (1.2%) decrease of body mass occurred from prepractice to postpractice (p ≤ 0.01). Consistent with mild body mass losses, urinary indices of hydration status (i.e., color, specific gravity, and osmolality) indicated mild fluid deficits. A significant increase (p ≤ 0.05) from pre-to postpractice was observed in urine color and urine specific gravity, but chronic hypohydration over the 8 days was not noted. The Environmental Symptoms Questionnaire (ESQ) postpractice score was significantly higher (p ≤ 0.05) than the prepractice score was, but averages did not differ across practice days. There was no difference in postpractice TGI measurements across days (p ≤ 0.05). Heart rate, TGI, and ESQ measurements indicated that football players experienced gradual heat acclimatization and enhanced heat tolerance, despite progressive increases of exercise variables, clothing, and environmental stressors. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine pituitary-adrenal (PA) hormone responses [beta-endorphin (beta-END), adrenocorticotropic hormone (ACTH) and cortisol] to arm exercise (AE) and leg exercise (LE) at 60 and 80% of the muscle-group specific VO2 peak. Eight healthy untrained men (AE VO2 peak=32.4+/-3.0 ml kg(-1) min(-1), LE VO2 peak=46.9+/-5.3 ml kg(-1) min(-1)) performed two sub-maximal AE and LE tests in random order. Plasma beta-END, ACTH and cortisol were not different (P>0.05) between AE and LE at either exercise intensity; the 60% testing elicited no changes from pre-exercise (PRE) values. For 80% testing, plasma beta-END, ACTH and cortisol were consistently, but not significantly, greater during LE than AE. In general, plasma beta-END and ACTH were higher (P<0.05) during 80% exercise, than PRE, for both AE and LE. Plasma cortisol was elevated (P<0.05) above PRE during 80% LE, and following 80% for both AE and LE. Plasma ACTH was higher (P<0.05) during 80% LE and AE versus 60% LE and AE, respectively. Plasma beta-END and cortisol were significantly higher during and immediately after 80% LE than 60% LE. Thus, plasma beta-END, ACTH and cortisol responses were similar for AE and LE at the two relative exercise intensities, with the intensity threshold occurring somewhere between 60 and 80% of VO2 peak. It appears that the smaller muscle mass associated with AE was sufficient to stimulate these PA axis hormones in a manner similar to LE, despite the higher metabolic stress (i.e., plasma La-) associated with LE. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine pituitary–adrenal (PA) hormone responses [beta-endorphin (β-END), adrenocorticotropic hormone (ACTH) and cortisol] to arm exercise (AE) and leg exercise (LE) at 60 and 80% of the muscle-group specific VO2 peak. Eight healthy untrained men (AE VO2 peak=32.4±3.0 ml kg−1 min−1, LE VO2 peak=46.9±5.3 ml kg−1 min−1) performed two sub-maximal AE and LE tests in random order. Plasma β-END, ACTH and cortisol were not different ( P>0.05) between AE and LE at either exercise intensity; the 60% testing elicited no changes from pre-exercise (PRE) values. For 80% testing, plasma β-END, ACTH and cortisol were consistently, but not significantly, greater during LE than AE. In general, plasma β-END and ACTH were higher ( P<0.05) during 80% exercise, than PRE, for both AE and LE. Plasma cortisol was elevated ( P<0.05) above PRE during 80% LE, and following 80% for both AE and LE. Plasma ACTH was higher ( P<0.05) during 80% LE and AE versus 60% LE and AE, respectively. Plasma β-END and cortisol were significantly higher during and immediately after 80% LE than 60% LE. Thus, plasma β-END, ACTH and cortisol responses were similar for AE and LE at the two relative exercise intensities, with the intensity threshold occurring somewhere between 60 and 80% of VO2 peak. It appears that the smaller muscle mass associated with AE was sufficient to stimulate these PA axis hormones in a manner similar to LE, despite the higher metabolic stress (i.e., plasma La-) associated with LE. [ABSTRACT FROM AUTHOR]

Although endogenous and exogenous steroid hormones affect numerous physiological processes, the interactions of reproductive hormones, chronic exercise training, and heat acclimation are unknown. This investigation evaluated the re- sponges and adaptations of 36 inactive females [age 21 ± 3 (SD) yr] as they undertook a 7- to 8-wk program [heat acclimation and physical training (HAPT)J of indoor heat acclimation (90 mm/day, 3 day s/wk) and outdoor physical training (3 days/wk) while using either an oral estradiol-progestin contraceptive (ORAL, n = 15), a contraceptive injection of depot medroxyprogesterone acetate (DEPO, n = 7), or no contraceptive (EU-OV, n = 14; control). Standardized physical fitness and exercise-heat tolerance tests (36.5°C, 37% relative humidity), administered before and after HAPT, demonstrated that the three subject groups successfully (P < 0.05) acclimated to heat (i.e., rectal temperature, heart rate) and improved muscular endurance (i.e., sit- ups, push-ups, 4.6-km run time) and body composition characteristics. The stress of HAPT did not disrupt the menstrual cycle length/phase characteristics, ovulation, or plasma hormone concentrations of EU- OV. No between-group differences (P> 0.05) existed for rectal and skin temperatures or metabolic, cardiorespiratory, muscular endurance, or body composition variables. A significant difference post- HAPT in the onset temperature of local sweating, ORAL (37.2 ± 0.4°C) vs. DEPO (37.7 ± 0.2°C), suggested that steroid hormones influenced this adaptation. In summary, virtually all adaptations of ORAL and DEPO were similar to EU-OV, suggesting that exogenous reproductive hormones neither enhanced nor impaired the ability of women to complete 7-8 wk of strenuous physical training and heat acclimation. [ABSTRACT FROM AUTHOR]

Athletes are required to provide objective documentation of exercise-induced bronchoconstriction(EIB) to useβ2-agonists during Olympic competition. A positive response to bronchial provocation by eucapnic voluntary hyperventilation(EVH) is considered acceptable confirmation of EIB. Thirty times forced expiratory volume in the first second(FEV1) is recommended as EVH target ventilation(TV), an intensity intended to estimate 85% of maximal voluntary ventilation(MVV). There is a paucity of data examining the accuracy of predicting MVV from FEV1 in elite athletes. The purpose of this study was to evaluate the efficacy of 30 × FEV1 as standardized EVH TV. Maximal minute ventilation during exercise(VEmax) and pulmonary function of 78 elite winter athletes(25 males, 53 females; 25 EIB positive, 53 normal) were analyzed retrospectively. Adequacy and variability of the equation was ascertained by examining the ratio of EVH TV(30 × FEV1) to VEmax. VEmax was 99 ± 11% of predicted MVV(35 × FEV1) and was positively related(r = 0.85, p ≤ 0.05). TV was 88 ± 9% of VEmax(range: 64–109). For elite athletes, the high variability in 30 × FEV1 to standardize TV for EVH may result in under-diagnosis for low-end outliers. Since VEmax of elite endurance athletes is typically known(via maximal aerobic testing) we recommend 85% VEmax as a more accurate and reliable method to establish EVH TV for this group; if VEmax is not available, then 85% of measured MVV may be used. [ABSTRACT FROM AUTHOR]

Study objective: For the 2002 Winter Olympic Games, athletes were required to submit objective evidence of asthma or exercise-induced bronchoconstriction (EIB) for approval to inhale a β2-agonist. Eucapnic voluntary hyperventilation (EVH) was recommended as a laboratory challenge that would identify airway hyperresponsiveness (AHR) consistent with EIB. The objective was to compare the change in FEV1 provoked by EVH with that provoked by exercise in cold weather athletes. Design: Spirometry was measured before and for 15 min after challenges. The two challenges were performed in random order at least 24 h apart. Setting: EVH was performed in the laboratory at 19°C, and exercise took place in the field in the cold (2°C, 45% relative humidity). Participants: Thirty-eight athletes (25 female subjects; median age, 16 years). Interventions: For the EVH, athletes inhaled dry air containing 5% carbon dioxide for 6 min at a target ventilation equivalent to 30 times baseline FEV1. Exercise was performed by cross-country skiing, ice skating, or running for 6 to 8 min. Measurements and results: AHR consistent with EIB was defined as ≥10% fall in FEV1 from baseline after challenge. Eleven athletes were exercise positive (EX+) [FEV1 fall, 20.5 ± 7.3%], and 17 athletes were EVH positive (FEV1 fall, 14.5 ± 4.5%) [mean ± SD]. Of 19 subjects with AHR, 58% were identified by exercise and 89% were identified by EVH. EVH identified 9 of 11 subjects who were EX+ and a further 8 subjects with potential for EIB. The average ventilation during EVH was 28 times FEV1. Conclusion: Performing EVH for 6 min in the laboratory had a greater chance of identifying AHR in these athletes compared with 6 to 8 min of field exercise in the cold. The EVH test will be useful to evaluate elite summer sports athletes whose widely different forms of exercise provide an "equipment" challenge to any laboratory. [ABSTRACT FROM AUTHOR]