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Starting stance plays an important role in influencing short-distance sprint speed and, therefore, the ability to reach a ball during sport play. The purpose of this study was to evaluate 4 different starting stances on sprint time. Twenty-six male and female collegiate volleyball players volunteered to participate in 1 testing session. Each subject performed 3 15-ft sprint trials at each of 4 different starting stances (P--parallel, FS--false step, S--staggered, and SFS--staggered false step) in random order. Analysis of variance revealed that there was no significant interaction of sex by stance, but there were main effects for sex (men were faster than women) and stance. The FS (1.18 [+ or -] 0.10 seconds), S (1.16 [+ or -] 0.07 seconds), and SFS (1.14 [+ or -] 0.06 seconds) stances were faster than the P (1.25 [+ or -] 0.09 seconds) stance, and the SFS stance was faster than the FS stance. This indicates that starting with a staggered stance (regardless of stepping back) produced the greatest sprinting velocity over the initial 15 feet. Although taking a staggered stance seems counterproductive, the resultant stretch-shortening cycle action and forward body lean likely increase force production of the push-off phase and place the total body center of mass ahead of the contacting foot, thereby, decreasing sprint time. KEY WORDS Staggered false step, foot position

The aim of this study was to examine the effects of a stable surface (bench) vs. an unstable surface (Swiss ball) on muscle activation when performing the dumbbell chest press and shoulder press. Sixteen healthy men (24.19 [+ or -] 2.17 years) performed 1 repetition maximum (1RM) tests for the chest press and shoulder press on a stable surface. A minimum of 48 hours post 1RM, subjects returned to perform 3 consecutive repetitions each of the chest press and shoulder press at 80% 1 RM under 4 different randomized conditions (chest press on bench, chest press on Swiss ball, shoulder press on bench, shoulder press on Swiss ball). Electromyography was used to assess muscle activation of the anterior deltoid, pectoralis major, and rectus abdominus. The results revealed no significant difference in muscle activation between surface types for either exercise. This suggests that using an unstable surface neither improves nor impairs muscle activation under the current conditions. Coaches and other practitioners can expect similar muscle activation when using a Swiss ball vs. a bench. KEY WORDS electromyography, stable surface, unstable surface, muscle activation

The bench press exercise exists in multiple forms including the machine and free weight bench press. It is not clear though how each mode differs in its effect on muscle activation. The purpose of this study was 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. Normalized electromyography amplitude values were used during the concentric phase of the bench press to compare muscle activity between a free weight and Smith machine bench press. Participants were classified as either experienced or inexperienced bench pressers. Two testing sessions were used, each of which entailed either all free weight or all Smith machine testing. In each testing session, each participant's 1RM was established followed by 2 repetitions at 70% of 1RM and 2 repetitions at 90% of 1 RM. Results indicated greater activation of the medial deltoid on the free weight bench press than on the Smith machine bench press. Also, there was greater muscle activation at the 90% 1 RM load than at the 70% 1 RM load. The results of this study suggest that strength coaches should consider choosing the free weight bench press over the Smith machine bench press because of its potential for greater upper-body muscular development. KEY WORDS EMG, experience level, medial deltoid

Research examining postactivation potentiation (PAP) in recreationally trained individuals (RTI) shows mixed results. Because the balance of PAP and fatigue after heavy-load exercise influences performance outcomes, recovery duration after the stimulus might explain inconsistent results noted in RTI. The purpose of this study was to investigate the effect of recovery duration after a potentiating stimulus on muscular power in RTI. Twelve healthy RTI males (age = 23 [+ or -] 1 yr, height = 174.6 [+ or -] 2.5 cm, mass = 86.3 [+ or -] 6.6 kg, 1 repetition maximum [1RM]:mass= 1.4 [+ or -] 0.1, body fat = 15.1 [+ or -] 2.5 %) minimally possessing 1 year of back squat experience participated. A control session assessed baseline measures on a 30-second Wingate Test. During experimental sessions, subjects performed a back squat exercise (1 set of 5 repetitions at 85% 1RM), rested for 5, 10, 15, or 20 minutes, and performed the Wingate Test. No significant differences existed among control and experimental conditions in all outcome variables; however, maximal values (regardless of rest duration) for absolute peak power (APpwr) (+7.1%), relative peak power (RPpwr) (+7.1%), and fatigue index (FI) (+8.9%) significantly differed from respective control values. The rest duration eliciting maximal PAP significantly correlated (r = -0.771) with relative 1RM. Although recovery duration failed to influence performance after a heavy-load exercise in RTI, discrepancies in individual strength might have influenced the time subjects potentiated. These results suggest stronger subjects might potentiate with less rest after a stimulus (5-10 min), whereas weaker subjects require longer rest durations (15-20 min). KEY WORDS performance, postactivation potentiation, rest, strength, Wingate

High-force activities have demonstrated postactivation potentiation (PAP) and may enhance performance in athletes; however, the efficacy of high-force activities to generate PAP in recreationally trained men remains unclear. The purpose of this study was to investigate the effect of high-force back squat volume on vertical jump (VJ) height, ground reaction force (GRF), impulse (IMP), and takeoff velocity (TOV) in recreationally trained men. Sixteen recreationally trained men (age 24.56 [+ or -] 2.10 years, height 174.53 [+ or -] 8.54 cm, mass 84.59 [+ or -] 14.75 kg, and 1 repetition maximum [1RM] back squat 124.71 [+ or -] 17.58 kg) with at least 1 year of back squat experience completed 5 testing sessions separated by a minimum of 72 hours' rest. On session 1, subjects completed VJ testing without a potentiating exercise intervention (control condition) in a test-retest fashion (3 VJs, 5 minutes seated rest, and 3 more VJs) and performed 1RM back squat testing. Subjects completed the subsequent 4 testing sessions in a test-retest fashion (3 VJs, experimental condition, 5 minutes seated rest, and 3 more VJs) in random order. The 4 experimental conditions required subjects to perform the back squat using a load of 85% 1 RM with volumes of 1 x 2, 1 x 3, 1 x 4, or 1 x 5. Analysis of variance revealed no significant (p > 0.05) condition by time interactions for any dependent variable; however, there were significant (p < 0.05) main effects for time for GRF (pre 2,123.74 [+ or -] 422.86 N, > post 2,094.53 [+ or -] 390.99 N) and IMP (pre 210.88 [+ or -] 100.97 N x s, > post 204.63 [+ or -] 106.14 N x s) but not for VJ or TOV. These results suggest that 85% 1RM back squat volume assignments do not produce a VJ potentiation response in recreationally trained men. KEY WORDS postactivation, back squat, ground reaction force, velocity

Eccentric muscle actions cause muscle damage and lead to delayed-onset muscle soreness (DOMS), which may impair performance. The purpose of this study was to examine the effect of DOMS on elbow flexion strength and rate of velocity development (RVD). Nineteen college male subjects performed 6 tests (pre- and posteccentric and every 24 hours for 4 days). In the preeccentric tests, each subject reported his arm pain and then did 5 concentric repetitions of elbow flexion/extension on an isokinetic dynamometer at 240[degrees]. [s.sup.-1]. Each subject then completed 6 sets of 10 eccentric elbow flexion actions at 30[degrees].s 1 and finished with a posteccentric test with another 5 concentric repetitions at 240[degrees] x [s.sup.-1]. On days 1-4, each subject reported his arm pain and then did 5 more repetitions at 240[degrees]-s 1. Analysis was performed on the values for DOMS, peak torque (PT), and RVD. For DOMS, scores on the posteccentric test (2.34 [+ or -] 2.53), day 1 (3.18 [+ or -] 2.18), day 2 (3.21 [+ or -] 2.91), day 3 (1.81 [+ or -] 1.78), and day 4 (1.02 [+ or -] 1.30) were all significantly (p < 0.05) greater than the preeccentric scores (0.00 [+ or -] 0.00). For PT, the scores on the posteccentric test (22.40 [+ or -] 8.87 ft-lb 1) and day 1 (23.88 [+ or -] 9.00 ft x [lb.sup.-1]) were both significantly less than on the preeccentric test (29.56 [+ or -] 8.42 ft x [lb.sup.-1]). The RVD scores on the posteccentric test (1505.73 [+ or -] 462.12 d x [s.sup.-1] x [s.sup.-1]), day 1 (1571.55 [+ or -] 475.99 d x [s.sup.-1] x [s.sup.-1]), and day 2(1546.99 [+ or -] 494.52 d x [s.sup.-1] x [s.sup.-1]) were all significantly less than on the preeccentric test (1719.86 [+ or -] 473.18 d x [s.sup.-1] x [s.sup.-1]). This suggests that muscle damage may cause significant decreases in elbow flexion concentric strength and RVD even as DOMS remains elevated. WORDS speed, acceleration, power

It is well established that resistance exercise can damage muscle tissue, but the combined effects of hypohydration and resistance exercise on muscle damage are unclear. Two common circulating markers of muscle damage, myoglobin (Mb) and creatine kinase (CK) may be attenuated by fluid ingestion post-exercise. The purpose of this study was to examine the combined effect of resistance exercise and hydration state on muscle damage. Seven healthy resistance-trained males (age = 23 [+ or -] 4 years; body mass = 87.8 [+ or -] 6.8 kg; body fat = 11.5 [+ or -] 5.2%) completed 3 identical resistance exercise bouts (6 sets of up to 10 repetitions of the back squat) in different hydration states: euhydrated (HYO), hypohydrated ~2.5% body mass (HY2.5), and hypohydrated ~5.0% body mass (HY5). Subjects achieved desired hydration states via controlled water deprivation, exercise-heat stress, and fluid intake. Both Mb and CK were measured during euhydrated rest (PRE). Mb was also measured immediately post-exercise, 1 hour (+1H) and 2 hours (+2H) post-exercise; CK was measured at 24 and 48 hours post-exercise. Body mass decreased 0.2 [+ or -] 0.4%, 2.4 [+ or -] 0.4%, and 4.8 [+ or -] 0.4% during HY0, HY2.5, and HY5, respectively. Mb concentrations increased significantly (effect size [greater than or equal to] 1, p < 0.05) from PRE (2.6 [+ or -] 1.1,3.5 [+ or -] 2.8, and 3.2 [+ or -] 1.6 nmol*[L.sup.-1]) to +1H (5.3 [+ or -] 3.4, 6.8 [+ or -] 3.2, and 7.6 [+ or -] 2.8 nmol*[L.sup.-1]), and +2H (5.5 [+ or -] 3.8, 6.2 [+ or -] 3.0, and 7.2 [+ or -] 3.0 nmol*[L.sup.-1]) for HY0, HY2.5, and HY5, respectively, but were not significantly different between trials. CK concentrations remained within the normal resting range at all time points. Thus, hypohydration did not enhance muscle damage following the resistance exercise challenge. Despite these results, athletes are encouraged to commence exercise in a euhydrated state to maximize endogenous hormonal, mechanical, and metabolic benefits. KEY WORDS hypohydration, exercise-induced damage, muscle protein

The ergogenic effects of caffeine on athletic performance have been shown in many studies, and its broad range of metabolic, hormonal, and physiologic effects has been recorded, as this review of the literature shows. However, few caffeine studies have been published to include cognitive and physiologic considerations for the athlete. The following practical recommendations consider the global effects of caffeine on the body: Lower doses can be as effective as higher doses during exercise performance without any negative coincidence; after a period of cessation, restarting caffeine intake at a low amount before performance can provide the same ergogenic effects as acute intake; caffeine can be taken gradually at low doses to avoid tolerance during the course of 3 or 4 days, just before intense training to sustain exercise intensity; and caffeine can improve cognitive aspects of performance, such as concentration, when an athlete has not slept well. Athletes and coaches also must consider how a person's body size, age, gender, previous use, level of tolerance, and the dose itself all influence the ergogenic effects of caffeine on sports performance. KEY WORDS ergogenic aid, athletic performance, cognitive, habituation

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 [+ or -] 1.3 years; height = 177.6 [+ or -] 6.4 cm; body mass = 77.6 [+ or -] 8.6 kg, and percentage body fat = 12.8 [+ or -] 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 ([Vo.sub.2]max). 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 [less than or equal to] 96 and workload was [greater than or equal to] 80% of 1 repetition maximum). For the entire team, body mass significantly increased by 1.5 [+ or -] 0.4 kg from PRE to POST due to a significant increase in total lean tissue (0.9 [+ or -] 0.2 kg). Regionally, lean tissue mass significantly increased in the legs (0.4 [+ or -] 0.0 kg) and trunk (0.3 [+ or -] 0.1 kg). Physical performance variables were very similar for the entire team at PRE and POST; VJ (cm) = 61.9 [+ or -] 7.1 PRE vs. 63.3 [+ or -] 8.0 POST, 9.1-m (s) = 1.7 [+ or -] 0.1 PRE and POST, 36.5-m (s) = 5.0 [+ or -] 0.2 PRE and POST, predicted [Vo.sub.2]max (ml x kg x [min.sup.-1] = 59.8 [+ or -] 3.3 PRE vs. 60.9 [+ or -] 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. KEY WORDS. starters, nonstarters, DEXA, conditioning, strength training

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 [+ or -] 1 year, 1.88 [+ or -] 0.05 m, and 115.36 [+ or -] 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 ([T.sub.GI]) 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 [T.sub.GI] measurements across days (p < 0.05). Heart rate, [T.sub.GI], 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. Key Words. core body temperature, hydration, football uniform, surface area-to-mass ratio

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 responses and adaptations of 36 inactive females [age 21 [+ or -] 3 (SD) yr] as they undertook a 7- to 8-wk program [heat acclimation and physical training (HAPT)] of indoor heat acclimation (90 min/day, 3 days/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[degrees]C, 37% relative humidity), administered before and alter 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 [+ or -] 0.4[degrees]C) vs. DEPO (37.7 [+ or -] 0.2[degrees]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. estrogen; progesterone; estradiol; progestin; rectal temperature

Preparation for the physical demands of competition often involves game simulation during practice. This paradigm is thought to promote physiological adaptations that enhance maximal performance. However, a mismatch between practice intensity and actual competition intensity may not provide adequate training to achieve optimal game-play fitness. The purpose of this study was to evaluate the effectiveness of practice in meeting the cardiovascular demands of a women's ice hockey game. Heart rate (HR) data from 11 U.S. National Women's Ice Hockey team members were collected (5second intervals) during a game and a typical practice session. Data was normalized to individual HRmax determined during V[O.sub.2]max testing. Working time was defined as a game shift or practice-working interval. Mean working HR was greater during the game than the practice, 90 [+ or -] 2% and 76 [+ or -] 3% of HRmax, respectively (p < 0.05). Mean percent session time (game or practice) >90% HRmax was also longer during the game than the practice, 10.5 [+ or -] 4.1% and 5.6 [+ or -] 3.5% (p < 0.05), respectively. Mean session HR, percent time >80% HRmax, and mean resting HR were not different between game and practice (68 [+ or -] 7% vs. 69 [+ or -] 5%, 23.2 [+ or -] 5.3% vs. 26.1 [+ or -] 9.2%, and 59 [+ or -] 8% vs. 56 [+ or -] 5%, respectively). Elite women hockey players experience significantly greater cardiovascular load during game play than during practice. This mismatch in cardiovascular demand may prevent players from achieving 'game shape,' thus affecting competition play. Key Words: anaerobic exercise, game conditioning, ice skating, intermittent work, interval training