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Lamont, HS, Cramer, JT, Bemben, DA, Shehab, RL, Anderson, MA, and Bemben, MG. The acute effect of whole-body low-frequency vibration on countermovement vertical jump performance in college-aged men. J Strength Cond Res 24(12): 3433-3442, 2010--The purpose of this study was to examine the acute effects of whole-body vibration on jump performance. A total of 21 college-aged men, 18-30 years, recreationally resistance trained, were exposed to a total of 4 different acute whole-body low-frequency vibration (WBLFV) protocols (conditions 1-4), performing 2 protocols per testing session in random order. Exposures were all performed using high-amplitude (peak-peak 4-6 mm) and either 30 or 50 Hz for 30 continuous seconds, or 3 exposures of 10 seconds with 1 minute between exposures. Three countermovement vertical jumps (CMVJs) were performed before vibration (testing phase 1 or Tp1 and J1 the highest of 3 attempts) and at 3 separate time points postvibration (Tp2-4). Jump height (cm), peak power ([P.sub.max]), peak power per kilogram of body mass ([P.sub.max] [kg.sub.-1]), mean power ([P.sub.av]), and mean velocity ([V.sub.av]) were recorded. Repeated measures analysis of variance and analysis of covariance revealed no significant condition (C) or jump (J) differences for CMVJ height (cm) (p > 0.05). Analysis of percent change ([DELTA]%) for CMVJ height (cm) revealed a significant Condition x Jump interaction, C4, J3 > C1, J3 (p = 0.009, mean diff 4.12%). Analysis of [P.sub.max] and [P.sub.max] [kg.sup.-1] revealed no significant Condition, Jump, or Condition x Jump interaction for the raw data or percent change (p > 0.05). Analysis of Pay (W) revealed significant differences for Condition (p = 0.031) but not for Jump (p = 0.226). There was a strong trend toward significance for Condition x Jump interaction (p = 0.059). C4 > C3 (p = 0.043, mean diff 23.78 W) and C1 (p = 0.038, mean diff 32.03 W). Analysis of [V.sub.av] (m x [s.sup.-1]) revealed no significant main effects for Condition or Jump (p > 0.05) but found a significant Condition x Jump interaction (p = 0.007). C4, J6 > C2, J6 (p = 0.014, mean diff 0.05 m x [s.sup.-1]), and C3, J6 (p = 0.020, 0.05 m x [s.sup.-1]). WBLFV applied intermittently using 50 Hz appears to be more effective than other protocols using 30 and 50 Hz in facilitating select measures of CMVJ performance over a 17-minute time period post-WBLFV exposure. Practical manipulation of such a WBLFV 'dose' may be beneficial to strength and conditioning practitioners wanting to acutely facilitate CMVJ and slow stretch shortening cycle performance while minimizing exposure time. KEY WORDS stretch shortening cycle, jump performance, postactivation potentiation

The purpose of the present study was to examine musculotendinous stiffness (MTS) and ankle joint range of motion (ROM) in men and women after an acute bout of passive stretching. Thirteen men (mean [+ or -] SD age = 21 [+ or -] 2 years; body mass = 79 [+ or -] 15 kg; and height = 1 77 [+ or -] 7 cm) and 19 women (21 [+ or -] 3 years; 61 [+ or -] 9 kg; 165 [+ or -] 8 cm) completed stretch tolerance tests to determine MTS and ROM before and after a stretching protocol that consisted of 9 repetitions of passive, constant-torque stretching. The women were all tested during menses. Each repetition was held for 135 seconds. The results indicated that ROM increased after the stretching for the women (means [+ or -] SD pre to post: 109.39[degrees] [+ or -] 10.16[degrees] to 116.63[degrees] [+ or -] 9.63[degrees]; p [less than or equal to]-< 0.05) but not for the men (111.79[degrees] -+ 6.84[degrees] to 113.93[degrees] [+ or -] 8.15[degrees]; p > 0.05). There were no stretching-induced changes in MTS (women's pre to postchange in MTS: -0.35 [+ or -] 0.38; men's MTS: +0.1 7 [+ or -] 0.40; p > 0.05), but MTS was higher for the men than for the women (MTS: 1.34 4 [+ or -] 0.41 vs. 0.97 [+ or -] 0.38; p [less than or equal to] 0.05). electromyographic amplitude for the soleus and medial gastrocnemius during the stretching tests was unchanged from pre to poststretching (p > 0.05); however, it increased with joint angle during the passive movements (p [less than or equal to] 0.05). Passively stretching the calf muscles increased stretch tolerance in women but not in men. But the stretching may not have affected the viscoelastic properties of the muscles. Practitioners may want to consider the possible gender differences in passive stretching responses and that increases in ROM may not always reflect decreases in MTS. KEY WORDS constant torque, viscoelastic properties, electromyography

DeFreitas, JM, Beck, TW, Stock, MS, Dillon, MA, Sherk, VD, Stout, JR, and Cramer, JT. A comparison of techniques for estimating training-induced changes in muscle cross-sectional area. J Strength Cond Res 24(9): 2383-2389, 2010--The ability to accurately estimate changes in muscle cross-sectional area (CSA) could be a useful tool for strength and conditioning practitioners to assess the effectiveness of a resistance training program. The purpose of this study was twofold: (a) to compare the reliability of 2 separate anthropometric-based field estimations of thigh muscle CSA with that of a more accurate, sophisticated imaging technique (peripheral quantitative computed tomography [pQCT] scanner) and (b) to determine if the field methods would be sensitive enough to detect changes in CSA during a resistance training program. Twenty-five healthy, untrained men completed 8 weeks of resistance training. Cross-sectional area testing occurred twice before the start of training, for reliability and again every 2 weeks during the study. Testing consisted of a pQCT scan of the right thigh followed by circumference and skinfold measurements. Two separate equations (Moritani and deVries [M + D] and Housh multiple regression [HMR]) were used to estimate CSA from the anthropometric data. The M + D and HMR methods demonstrated intraclass correlations of 0.983 and 0.961, respectively, but both significantly underestimated thigh muscle CSA when compared to the pQCT. This error was consistent, however, and consequently, the field methods were able to demonstrate increases in muscle CSA with a pattern similar to those from the pQCT. Thus, these equations can be useful tools to evaluate an athlete's progress toward the goal of increasing muscle CSA. It is the authors' hope that the present study will increase awareness among practitioners of these useful field methods for estimating training-induced changes in muscle CSA. KEY WORDS anthropometry; pQCT, hypertrophy

Energy drink use has grown despite limited research to support efficacy or safety and amid concerns when combined with exercise. The purpose of this study was to assess the effects of 10 weeks of once-daily energy drink consumption or energy drink consumption with exercise on measures of body composition, cardiorespiratory fitness, strength, mood, and safety in previously sedentary males. Thirty-eight males were randomly assigned to energy drink + exercise (EX-A), energy drink (NEX-A), placebo + exercise (EX-B), or placebo (NEX-B). All participants consumed 1 drink per day for 10 weeks; EX-A and EX-B participated in 10 weeks of resistance and endurance exercise. Testing was performed before (PRE) and after (POST) the 10-week intervention. No significant (p > 0.05) changes were observed for body composition, fitness, or strength in NEX-A; however, significantly greater decreases in fat mass and percentage body fat and increases in [VO.sub.2]peak were observed in EX-A versus EX-B. Ventilatory threshold (VT), minute ventilation, [[??]O.sub.2] at VT, and power output at VT improved significantly PRE to POST in EX-A but not in EX-B or nonexercising groups. Clinical markers for hepatic, renal, cardiovascular, and immune function, as determined by PRE and POST blood work revealed no adverse effects in response to the energy drink. Mood was not affected by energy drink use. Absent energy restriction or other dietary controls, chronic ingestion of a once-daily low-calorie energy drink appears ineffective at improving body composition, cardiorespiratory fitness, or strength in sedentary males. However, when combined with exercise, preworkout energy drink consumption may significantly improve some physiological adaptations to combined aerobic and resistance training. KEY WORDS caffeine, thermogenic, body composition, taurine, EGCG, green tea

Creatine (Cr) loading consists of short-term, high-dosage Cr supplementation and has been shown to increase intramuscular total Or content. Increases in body weight (BW) have been shown to result from Cr loading, with differences by gender, and increased BW may impact weight-bearing exercise. The critical velocity (CV) test is used to quantify the relationship between total running distance and time to exhaustion. The CV test provides the variable, anaerobic running capacity (ARC), which is an estimate of the anaerobic energy reserves in muscle. The purpose of this study was to examine the effects of gender and Cr loading on ARC. Fifty moderately trained men and women volunteered to participate in this randomized, double-blinded, placebo (PL)controlled, repeated-measures study. After a familiarization session, a 3-day testing procedure was conducted. A maximal oxygen consumption test ([[??]o.sub.2]max) on a treadmill was performed on day 1 to establish the maximum velocity (Vmax) at [[??]o.sub.2]max and to record BW. Days 2 and 3 involved treadmill running at varying percentages of Vmax. Participants were randomly assigned to either the Cr or PL group and received 20 packets of the Cr supplement (1 packet = 5 g Cr citrate, 18 g dextrose) or 20 packets of the PL (1 packet = 18 g dextrose). After consuming 4 packets daily for 5 consecutive days, the 3-day testing procedure was repeated. The male Cr loading group exhibited a 23O/o higher (p = 0.003) ARC compared to the PL group. Nonsignificant BW increases were found for the Cr groups. These findings suggest that Cr loading may be an effective strategy for improving ARC in men, but not in women, and revealed only nonsignificant increases in BW. Creatine loading may be used before competition by athletes to provide improvements in high-intensity, short-duration activities. KEY WORDS ergogenic aids, treadmill running, sprint performance, body weight, high-intensity activity, critical velocity

The purpose of the present study was to evaluate the effects of cycle ergometry high-intensity interval training (HIIT) with and without [beta]-alanine supplementation on maximal oxygen consumption rate ([[??]o.sub.2]peak), cycle ergometer workload at the ventilatory threshold ([VT.sub.w]), and body composition. Forty-four women (mean [+ or -] SD age = 21.8 [+ or -] 3.7 years; height = 166.5 [+ or -] 6.6 cm; body mass (BM) = 65.9 [+ or -] 10.8 kg; [[??]o.sub.2]peak = 31.5 [+ or -] 6.2 ml x [kg.sup.-1] x [min.sup.-1]) were randomly assigned to 1 of 3 groups: [beta]-alanine (BA, n = 14) 1.5 g + 15 g dextrose powder; placebo (PL, n = 19) 16.5 g dextrose powder; or control (CON, n = 11 ). Testing was conducted at baseline (week 0), after 3 weeks (week 4), and after 6 weeks (week 8). [[??]o.sub.2]peak (ml x [kg.sup.-1] x [min.sup.-1]) and [VT.sub.w] were measured with a metabolic cart during graded exercise tests on a corival cycle ergometer, and body composition (percent fat = % fat and fat-free mass = FFM) were determined by air displacement plethysmography. High-intensity interval training was performed on a corival cycle ergometer 3 times per week with 5 2-minute work intervals and 1-minute passive recovery with undulating intensities (90-110% of the workload recorded at [[??]o.sub.2]peak) during each training session. [[??]o.sub.2]peak increased (p [less than or equal to] 0.05) in the BA and PL groups at weeks 4 and 8, but did not change (p > 0.05) for the CON group. [VT.sub.w] increased (p [less than or equal to] 0.05) for all groups at weeks 4 and 8. Body mass increased (p [less than or equal to] 0.05) only for the BA group at weeks 4 and 8, whereas %fat decreased (p [less than or equal to] 0.05) and FFM increased (p [less than or equal to] 0.05) at weeks 4 and 8 for all groups (BA, PL, and CON). Although it is unclear why [beta]-alanine supplementation increased BM, there was no additive effects for increasing [[??]o.sub.2]peak beyond the PL. Overall, these results suggested that HIlT may be an effective and time-efficient method of training to improve maximal oxygen uptake. KEY WORDS cycle ergometry, [[??]o.sub.2]peak, HIIT

J Strength Cond Res 24(1): 171-183, 2010--Resistance training interventions aimed at increasing lower-body power and rates of force development have produced varying results. Recent studies have suggested that whole-body low-frequency vibration (WBLFV) may elicit an acute postactivation potentiation response, leading to acute improvements in power and force development. Potentially, the use of WBLFV between sets of resistance training rather than during training itself may lead to increased recruitment and synchronization of high-threshold motor units, minimize fatigue potential, and facilitate the chronic adaptation to resistance exercise. The purpose of this study was to determine the effects of applying TriPlaner, WBLFV, prior to and then intermittently between sets of Smith machine squats on short-term adaptations in explosive isometric force expression. Thirty recreationally resistance trained men aged 18-30 were randomly assigned to 1 of 3 groups: resistance training only (SQT, n = 11), resistance plus whole-body vibration (SQTV, n = 13), or active control (CON, n = 6). An isometric squat test was performed prior to and following a 6-week periodized Smith machine squat program. Whole-body low-frequency vibration was applied 180 seconds prior to the first work set (50 Hz, 2-4 mm, 30 seconds) and intermittently (50 Hz, 4-6 mm, 3 x 10 seconds, 60 seconds between exposures) within a 240-second interset rest period. Subjects were instructed to assume a quarter squat posture while positioning their feet directly under their center of mass, which was modified using a handheld goniometer to a knee angle of 135 [+ or -] 5[degrees]. Instructions were given to subjects to apply force as fast and as hard as possible for 3.5 seconds. Isometric force (N) and rates of force development (N x [s.sup.-1]) were recorded from the onset of contraction ([F.sub.o]) to time points corresponding to 30, 50, 80, 100, 150, and 250 milliseconds, as well as the peak isometric rate of force development (PISORFD), and rate of force development to initial peak in force (RFDinitial). Repeated measures analysis of variance and analysis of covariance revealed no significant group by trial interactions for isometric rate of force development (ISORFD) between 0-30, 0-50, 0-80, 0-100, 0-150, and 0-250 milliseconds and PISORFD (p > 0.05). A significant group x trial interaction was seen for RFDinitial with SQTV >CG (p = 0.04, mean difference 997.2 N x [s.sup.-1]) and SQTV >SQT (p = 0.04, mean difference 1,994.22 N x [s.sup.-1]). Significant trial by covariate interactions (week one measures for ISORFD) and main effects for trial were observed for ISORFD between 0-80, 0-100, 0-and 150 milliseconds; PISORFD; and RFDinitial (p < 0.01). A significant trial effect was seen for Finitial (%) when expressed as a relative percentage of maximal voluntary contraction (MVC) (MVC = 100%) (p = 0.015; week 1 > week 7, mean difference, 5.82%). No significant differences were seen for any other force variables from the onset of contraction to MVC between weeks 1 and 7 (p > 0.05). The data suggest that there was a significant benefit afforded by adding WBLFV to a short-term resistance training protocol with regard to 'explosive' strength expression. The addition of vibration prior to and between sets of resistance exercise may be a viable alternative to vibration applied during resistance exercise when trying to improve 'explosive' isometric strength. KEY WORDS explosive strength, low-frequency vibration, potentiation, rate of force development, resistance training

J Strength Cond Res 24(1): 109-113, 2010--The submaximal electromyographic fatigue threshold test ([EMG.sub.FT]) has been shown to be highly correlated to ventilatory threshold (VT) as determined from maximal graded exercise tests (GXTs). Recently, a prediction equation was developed using the [EMG.sub.FT] value to predict VT. The aim of this study, therefore, was to determine if this new equation could accurately track changes in VT after high-intensity interval training (HILT). Eighteen recreationally trained men (mean [+ or -] SD; age 22.4 [+ or -] 3.2 years) performed a GXT to determine maximal oxygen consumption rate ([Vo.sub.2]peak) and VT using breath-by-breath spirometry. Participants also completed a discontinuous incremental cycle ergometer test to determine their [EMG.sub.FT] value. A total of four 2-minute work bouts were completed to obtain 15-second averages of the electromyographic amplitude. The resulting slopes from each successive work bout were used to calculate [EMG.sub.FT]. The [EMG.sub.FT] value from each participant was used to estimate VT from the recently developed equation. All participants trained 3 days a week for 6 weeks. Training consisted of 5 sets of 2-minute work bouts with 1 minute of rest in between. Repeated-measures analysis of variance indicated no significant difference between actual and predicted VT values after 3 weeks of training. However, there was a significant difference between the actual and predicted VT values after 6 weeks of training. These findings suggest that the EMGFT may be useful when tracking changes in VT after 3 weeks of HIIT in recreationally trained individuals. However, the use of [EMG.sub.FT] to predict VT does not seem to be valid for tracking changes after 6 weeks of HILT. At this time, it is not recommended that [EMG.sub.FT] be used to predict and track changes in VT. KEY WORDS cardiorespiratory fitness, muscle fatigue, interval training, cycling

The purpose of the present study was to determine if the combination of isometric knee extension strength and mechanomyographic (MMG) median frequency (MDF) could be used to estimate the percent (%) myosin heavy chain (MHC) Type II isoform content of the vastus lateralis. Five resistance-trained (mean [+ or -] SD age = 23.2 [+ or -] 3.7 years) and 5 aerobically trained (mean [+ or -] SD age = 32.6 [+ or -] 5.2 years) men volunteered to perform a 6-second isometric maximum voluntary contraction (MVC) of the dominant knee extensors at a joint angle of 90 degrees between the thigh and leg. During the isometric MVC, the surface MMG signal was detected from the vastus lateralis, and the MDF was calculated with the discrete Fourier transform. Following the isometric MVC and MMG measurements, muscle biopsies were taken from the vastus lateralis and analyzed for % MHC Type II isoform content. The results showed that neither isometric knee extension strength nor MMG MDF alone was significantly correlated with the % MHC Type II isoform content. The combination of isometric knee extension strength and MMG MDF, however, explained a significant proportion (i.e., 59.8%) of the variance in % MHC Type II isoform content, with a multiple correlation of R = 0.773 and a standard error of the estimate (SEE) of 15.4%. These findings indicated that a simple, time-efficient, and noninvasive test that simultaneously measures isometric strength and MMG MDF could be useful for estimating the % MHC Type II isoform content in well-trained men. KEY WORDS muscle fiber type, mechanomyography, force

The purpose of this study was to examine the effects of a 6-week, periodized squat training program with (SQTV) or without (SOT) whole-body low-frequency vibration (WBLFV) on acute improvements in jump height and power output over 3 separate testing occasions. Participants ranged in age from 18 to 30 years and were randomized into 1 of 3 groups (CG, or control group, n = 6; SQTV, n = 13; or SOT, n = 11 ). SQTV and SOT performed Smith machine back squat training twice per week with 3 to 5 sets of 55 90O/o of the 1-repetition maximum (1RM). The SQTV group also received WBLFV (50 Hz; 2-6-mm amplitude) during the 6-week training period before training (30 seconds, 2-4-mm amplitude) and between sets (3 bouts lasting 10 seconds each). Two 30-cm depth jumps and two 20-kg squat jumps were performed after an acute vibration protocol during weeks 1,3, and 7. Jump height (cm), peak power (Pmax), peak power per kilogram of body mass (Pmax/kg), and mean power (Pav) were recorded for the depth and squat jumps. Although there were no group by trial interactions, percent change in Pmax for the squat jump was greater (p < 0.01) for the SQTV group than for the SQT group post WBLFV. In addition, the percent change scores for jump height and Pmax/kg for the depth jump were greater (p < 0.05) for SQTV than for SQT following WBLFV exposure. WBLFV during the 6-week squat training program resulted in greater acute improvements in power output and jump height for both jump conditions compared to SOT alone. KEY WORDS periodized resistance training, jump performance, post-activatiOn potentiation

The critical power test provides 2 measures, critical power (CP) and anaerobic working capacity (AWC). In theory, the CP measurement represents the maximal power output that can be maintained without fatigue, and AWC is an estimate of work capacity associated with muscle energy reserves. High-intensity interval training (HIIT) has been shown to be an effective training method for improving endurance performance, including V[O.sub.2PEAK]. In addition, creatine (Cr) supplementation has been reported to improve AWC without training; however, it has shown no effect on CP. The purpose of this study was to examine the effects of 4 weeks of HIIT with Cr supplementation on CP and AWC. Forty-two recreationally active men volunteered to participate in this study. Participants were randomly assigned to 1 of 3 groups: Cr (n = 16), 10 g Cr + 10 g dextrose; placebo (PL, n = 16), 20 g dextrose; control (CON, n = 10), no treatment. Before and after supplementation, each participant performed a maximal oxygen consumption test (V[O.sub.2PEAK]) on a cycle ergometer to establish peak power output (PPO). Participants then completed a CP test involving 3 exercise bouts with the workloads set as a percentage of their PPO to determine CP and AWC. After a 2-week familiarization period of training and supplementing, PPO, CP, and AWC were remeasured before an additional 4 weeks of HIIT and supplementation were completed. Training consisted of 5 sets of 2-minute exercise bouts with 1 minute rest in between performed on the cycle ergometer, with intensities based on PPO. A significant improvement in CP was observed in the Cr group (6.72% [+ or -] 2.54%), whereas PL showed no significant change (3.87% [+ or -] 2.30%), and CON significantly decreased (6.27% [+ or -] 2.38%). Furthermore, no changes in AWC were observed in any of the groups after treatment. The current findings suggest that Cr supplementation may enhance the effects of intense interval endurance training on endurance performance changes. KEY WORDS ergogenic aids, cycle ergometry, muscle buffering capacity, endurance performance

Anthropometric equations, based on 2-compartment models, have been routinely used to estimate body composition in female college athletes; however, these equations are not without error. In an attempt to decrease the error associated with anthropometric equations, updated equations were developed using multiple-compartment models, although the validity of these equations has not yet been established. The purpose of the current investigation was to determine the validity of the updated anthropometric equations and compare them with previously validated generalized equations for estimating percent fat (%fat) in female athletes. Twenty-nine white female NCAA Division I athletes (20 [+ or -] 1 years) volunteered to have their %fat estimated using anthropometric measurements. Skinfold equations included generalized and updated equations and a height and weight--based equation. %fat values were compared with a criterion 4-compartment model. All equations produced low total error (TE) ([less than or equal to] 3.38%fat) and SEE values ([less than or equal to]2.97%fat) and high r values (r [greater than or equal to] 0.78). The 2 updated skinfold equations produced the highest constant error (CE) values, but the tightest limits of agreement ([less than or equal to] 1.58 [+ or -] 4.86%fat; CE [+ or -] 2SD) compared with the 3 generalized Jackson et al. equations ([less than or equal to] 0.92 [+ or -] 5.34%fat), whereas the limits of agreement for the height and weight--based equation ([+ or -] 6.00 %fat) were the widest. Compared with the updated skinfold equations, the generalized Jackson et al. skinfold equations produced nearly identical TE values. Results suggest that the updated skinfold equations are valid but not superior to the generalized Jackson et al. equations, and the height and weight-based equation of Fornetti et al. is not recommended due to the large individual error in this population. Additionally, more than 3 skinfold sites did not improve %fat values. Therefore, the Jackson et al. sum of 3 skinfold equation is the suggested skinfold equation in the white female NCAA Division I athletes. KEY WORDS multi-compartment model; skinfold, field method, body composition; sports

Herda, T J, Beck, TW, Ryan, ED, Smith, AE, Walter, AA, Hartman, M J, Stout, JR, and Cramer, JT. Effects of creatine monohydrate and polyethylene glycosylated creatine supplementation on muscular strength, endurance, and power output. J Strength Cond Res 23(3): 818-826, 2009--The purpose of this study was to examine the effects of a moderate dose of creatine monohydrate (CM) and two smaller doses of polyethylene glycosylated (PEG) creatine on muscular strength, endurance, and power output. Fifty-eight healthy men (mean [+ or -] SD: age, 21 [+ or -] 2 years; height, 1 76 [+ or -] 6 cm; body mass [BM], 75 [+ or -] 14 kg) volunteered and were randomly assigned to 1 of 4 groups: (a) placebo (PL; 3.6 g of microcrystalline cellulose; n = 15), (b) CM (5 g of creatine; n = 13), (c) small-dose PEG creatine (1.25 g of creatine: [PEG.sub.1.25]; n = 14), or (d) moderate-dose PEG creatine (2.50 g of creatine: [PEG.sub.2.50]; n = 16). Testing was conducted before (pre-) and after (post-) a 30-day supplementation period. Measurements included body mass, countermovement vertical jump (CVJ) height, power output during the Wingate test (peak power [PP] and mean power [MP]), 1 repetition maximum bench press ([1RM.sub.BP]), 1RM leg press ([1RM.sub.LP]) strength, and repetitions to failure at 80% of the 1RM for bench press ([REP.sub.BP]) and leg press ([REP.sub.LP]). BM and MP (W) increased (p [less than or equal to] 0.05) from pre- to postsupplementation for the CM group only, whereas [1RM.sub.BP] and [1RM.sub.LP] increased (p [less than or equal to] 0.05) for the CM, [PEG.sub.1.25], and [PEG.sub.2.50] groups. CVJ height (cm and cm x [kg.sup.-1]), MP (W x [kg.sup.-1]), PP (W and W x [kg.sup.-1]), [REP.sub.BP], and [REP.sub.LP] increased (p [less than or equal to] 0.05) for all groups. These findings indicated that the recommended safe dose of 5 g x d of CM increased BM and improved muscle strength ([1RM.sub.BP] and [1RM.sub.LP]). Smaller doses of PEG creatine (1.25 and 2.50 g x [d.sup.-1]) improved muscle strength ([1RM.sub.BP] and [1RM.sub.LP]) to the same extent as 5 g x [d.sup.-1] of CM, but did not alter BM, power output, or endurance. When compared to the PL group, neither CM nor PEG creatine supplementation improved peak power output (CVJ or PP), MP, or muscle endurance ([REP.sub.BP] or [REP.sub.LP]). Thus, PEG creatine may have ergogenic effects that are comparable to those of CM, but with a smaller dose of creatine. KEY WORDS wingate test, countermovement vertical jump, bench press, leg press

The purpose of present study was to examine the acute effects of a thermogenic nutritional supplement on energy expenditure (EE) and cardiovascular function at rest, during low-intensity exercise, and recovery from exercise. Twenty-eight healthy sedentary participants (mean [+ or -] SD; age, 22.3 [+ or -] 1.9 years; body mass index, 24.0 [+ or -] 3.7) volunteered for this randomized, double-blinded, placebo-controlled, crossover study. Each experimental trial was divided into 4 phases: (a) 30 minutes of initial resting, followed by the placebo of thermogenic nutritional supplementation, (b) 50 minutes of post-supplementation resting, (c) 60 minutes of treadmill walking (3.2-4.8 km x [h.sup.-1]), and (d) 50 minutes of postexercise recovery. Gas exchange variables measured by indirect calorimetry and heart rate (HR) were recorded during all 4 phases, blood pressure was only measured at rest, and rating of perceived exertion (RPE) was only recorded during exercise. EE and oxygen consumption rate ([Vo.sub.2]) were greater for the supplement than the placebo at 50 minutes after supplementation. Also, during the postsupplementation period, diastolic blood pressure (DBP) was higher at all time periods, whereas the respiratory exchange ratio (RER) was higher at 20 and 30 minutes for the supplement. During exercise, only [Vo.sub.2] and minute ventilation (VE) were greater for the supplement than the placebo, with HR being less than the placebo at 20 minutes for the men. Postexercise EE, [Vo.sub.2], systolic blood pressure (SBP), DBP, and HR (men only) at 10, 20, 30, and 50 minutes were greater for the supplement than the placebo. These findings indicated that the thermogenic nutritional supplement increased resting EE and exercise [Vo.sub.2] with only minimal effects on blood pressure and HR and no meaningful effects on RER or RPE. These results suggested that the combination of thermogenic ingredients in this nutritional supplement may be useful to help maintain a negative caloric balance but may not influence substrate use or perceived exertion. KEY WORDS thermogenesis, oxygen consumption rate, blood pressure, caffeine, capsaicin

The purpose of this study was to examine the effects of a 6-week, periodized squat training program, with or without whole-body low-frequency vibration (WBLFV), on jump performance. Males ranged in age from 20 to 30 years and were randomized into groups that did squat training with (SQTV, n = 13) or without (SQT, n = 11) vibration, or a control group (CG, n = 6). Measures of jump height (cm), peak power (Pmax), Pmax per kilogram of body mass (Pmax/kg), and mean power were recorded during 30-cm depth jumps and 20-kg squat jumps at weeks 1 (pretraining), 3 (midtraining), and 7 (posttraining). No significant group differences were seen for 30-cm depth jump height between weeks 1 and 7 (p > 0.05). Trial three (W7) measures were greater than those for trial two (W3) and trial one (W1) (p < 0.05). Significant group differences were seen for 20-kg squat jump height, with SQTV > SQT between weeks 1 and 7 (p < 0.05). Significant trial differences were seen, with W7 > W3 > W1 (p < 0.05) as well as for 30-cm depth jump Pmax percent change (W7 > W3 and W1 p < 0.05)). A significant trial effect was seen for 20-kg squat jump Pmax (W7 > W1, p < 0.05) and 20-kg squat jump Pmax/kg percent change (W7 > W3 > W1, p < 0.05). The addition of vibration to SQTV seemed to facilitate Pmax and mean power adaptation for depth jumps and Pmax for squat jumps, although not significantly (p > 0.05). Stretch reflex potentiation and increased motor unit synchronization and firing rates may account for the trends seen. Baseline squat strength, resistance training experience, and amplitude, frequency, and duration of application of WBLFV seem to be important factors that need to be controlled for. KEY WORDS periodized resistance training, jump performance, post activation depression

The purpose of this study was to examine the influence of myosin heavy chain (MHC) isoform composition and training status on the mechanomyographic (MMG) amplitude versus isometric torque relationship for the vastus lateralis. Five resistance-trained (mean [+ or -] SD age = 23.2 [+ or -] 3.7 years), 5 aerobically trained (mean [+ or -] SD age = 32.6 [+ or -] 5.2 years), and 5 sedentary (mean [+ or -] SD age = 23.4 [+ or -] 4.1 years) men performed isometric muscle actions of the leg extensors in 20% increments from 20% to 100% of the maximum voluntary contraction. Biopsies from the vastus lateralis revealed that the MHC composition for the resistance-trained subjects was 59.0 [+ or -] 4.2% Type IIa, 0.1 [+ or -] 0.1% Type IIx, and 40.9 [+ or -] 4.3% Type I. The aerobically-trained subjects had 27.4 [+ or -] 7.8% Type IIa, 0.0 [+ or -] 0.0% Type IIx, and 72.6 [+ or -] 7.8% Type I MHC. The sedentary subjects had 42.1 [+ or -] 7.8% Type IIa, 17.8 [+ or -] 6.4% Type IIx, and 40.1 [+ or -] 10.9% Type I MHC. There were no consistent patterns of responses for the resistance-trained, aerobically trained, or sedentary subjects for MMG amplitude versus torque. Thus, differences in MHC isoform composition and training status did not explain the unique torque-related patterns for MMG amplitude. KEY WORDS mechanomyography, muscle fiber type composition, training

The purpose of this study was to examine the acute effects of static versus dynamic stretching on peak torque (PT) and electromyographic (EMG), and mechanomyographic (MMG) amplitude of the biceps femoris muscle (BF) during isometric maximal voluntary contractions of the leg flexors at four different knee joint angles. Fourteen men ((mean [+ or -] SD) age, 25 [+ or -] 4 years) performed two isometric leg flexion maximal voluntary contractions at knee joint angles of 41[degrees], 61[degrees], 81[degrees], and 101 [degrees] below full leg extension. EMG ([micro]V) and MMG (m*[s.sup.-2]) signals were recorded from the BF muscle while PT values (Nm) were sampled from an isokinetic dynamometer. The right hamstrings were stretched with either static (stretching time, 9.2 [+ or -] 0.4 minutes) or dynamic (9.1 [+ or -] 0.3 minutes) stretching exercises. Four repetitions of three static stretching exercises were held for 30 seconds each, whereas four sets of three dynamic stretching exercises were performed (12-15 repetitions) with each set lasting 30 seconds. PT decreased after the static stretching at 81 [degrees] (p=0.019) and 101[degrees] (p= 0.001) but not at other angles. PT did not change (p > 0.05) after the dynamic stretching. EMG amplitude remained unchanged after the static stretching (p > 0.05) but increased after the dynamic stretching at 101[degrees] (p < 0.001) and 81[degrees] (p < 0.001). MMG amplitude increased in response to the static stretching at 101[degrees] (p = 0.003), whereas the dynamic stretching increased MMG amplitude at all joint angles (p [less than or equal to] 0.05). These results suggested that the decreases in strength after the static stretching may have been the result of mechanical rather than neural mechanisms for the BF muscle. Overall, an acute bout of dynamic stretching may be less detrimental to muscle strength than static stretching for the hamstrings. KEY WORDS stretching-induced force deficit, EMG, MMG, hamstrings

The purpose of this study was to examine the effects of a drink containing creatine, amino acids, and protein vs. a carbohydrate placebo on body composition, strength, muscular endurance, and anaerobic performance before and after 10 weeks of resistance training. Fifty-one men (mean [+ or -] SD; age: 21.8 [+ or -] 2.9 years) were randomly assigned to either the test drink (TEST; n = 23) or the placebo (PLAC; n = 28) and performed two 30-second Wingate Anaerobic Tests for determination of peak power (PP) and mean power (MP), were weighed underwater for percent body fat (%fat) and fat-free mass (FFM), and were tested for 1 repetition maximum (1RM) dynamic constant external resistance strength and muscular endurance (END; number of repetitions performed with 80% of 1RM) on the bilateral leg extension (LE) and free-weight bench press (BP) exercises. The testing was conducted before (PRE) and after (POST) 10 weeks of resistance training (3 sets of 10 repetitions with 80% of the subject's 1RM performed 3 times per week) on the LE and BP exercises. Body weight, FFM, LE 1RM, LE END, BP 1RM, and BP END increased (p < 0.05), whereas %fat decreased (p < 0.05) from PRE to POST for both the TEST and PLAC groups. Peak power and MP, however, increased for the TEST group, but not for the PLAC group. These results suggested that the creatine-, amino acid-, and protein-containing drink provided no additional benefits when compared with carbohydrates alone for eliciting changes in body composition, strength, and muscular endurance after a 10-week resistance training period. The TEST drink was, however, more effective than carbohydrates alone for improving anaerobic power production. KEY WORDS. anaerobic power, nutritional supplement, bench press, leg extension

The purpose of this study was to examine the effects of 28 days of beta-alanine (b-Ala) and creatine monohydrate (CrM) supplementation on the onset of neuromuscular fatigue by using the physical working capacity at neuromuscular fatigue threshold ([PWC.sub.FT]) test in untrained men. Fifty-one men (mean age [+ or -] SD = 24.5 [+ or -] 5.3 years) volunteered to participate in this 28-day, double-blind, placebo-controlled study and were randomly assigned to 1 of 4 groups: placebo (PLA; 34 g dextrose; n = 13), CrM (5.25 g CrM plus 34 g dextrose; n = 12), b-Ala (1.6 g b-Ala plus 34 g of dextrose; n = 12), or b-Ala plus CrM (CrBA; 5.25 g CrM plus 1.6 g b-Ala plus 34 g dextrose; n = 14). The supplement was ingested 4 times per day for 6 consecutive days, then twice per day for 22 days before posttesting. Before and after the supplementation, subjects performed a continuous incremental cycle ergometry test while a surface electromyographic signal was recorded from the vastus lateralis muscle to determine [PWC.sub.FT]. The adjusted mean posttest [PWC.sub.FT] values (covaried for pretest [PWC.sub.FT] values) for the b-Ala and CrBA groups were greater than those for the PLA group (p [less than or equal to] 0.05). However, there were no differences between the CrM vs. PLA, CrBA vs. b-Ala, CrM vs. b-Ala, or CrM vs. CrBA groups (p > 0.05). These findings suggested that b-Ala supplementation may delay the onset of neuromuscular fatigue. Furthermore, there appeared to be no additive or unique effects of CrM vs. b-Ala alone on [PWC.sub.FT] KEY WORDS. carnosine, ergogenic aids, electromyography, cycle ergometry

The purpose of this investigation was to examine the effects of 3 days of velocity-specific isokinetic training on peak torque (PT) and the electromyographic (EMG) signal. Thirty adult women were randomly assigned to a slow-velocity training (SVT), fast-velocity training (FVT), or control (CON) group. All subjects performed maximal, concentric, isokinetic leg extension muscle actions at 30 and 270[degrees] x [s.sup.-1] for the determination of PT on visits 1 (pretest) and 5 (posttest). Electromyographic signals were recorded from the vastus lateralis, rectus femoris, and vastus medialis muscles during each test. The training groups performed 4 sets of 10 maximal repetitions at 30[degrees] x [s.sup.-1] (SVT group) or 270[degrees] x [s.sup.-1] (FVT group) on visits 2, 3, and 4. For the SVT group, PT increased from pretest to posttest at 30 and 270[degrees] x [s.sup.-1]. The increase in PT at 30[degrees] x [s.sup.-1] was greater than at 270[degrees] x [s.sup.-1]. For the FVT group, PT increased at 270[degrees] x [s.sup.-1] only. For the CON group, there were no changes in PT at either velocity. There were no pretest to posttest changes in EMG amplitude or mean power frequency (MPF) for any group at any velocity, with the exception of an increase in EMG MPF from the vastus medialis muscle at 270[degrees] x [s.sup.-1] for the FVT group. The results indicated that 3 sessions of slow velocity (30[degrees] x [s.sup.-1]) isokinetic training resulted in an increase in PT at slow and fast velocities (30 and 270[degrees] x [s.sup.-1]), whereas training at the fast velocity (270[degrees] x [s.sup.-1]) increased PT only at 270[degrees] x [s.sup.-1]. The lack of consistent increases in EMG amplitude or MPF suggested that the training-induced increases in leg extension PT were not caused by increased activation of the superficial muscles of the quadriceps femoris. The important implication for coaches, trainers, and physical therapists is that significant muscular performance gains may be achieved even after very short training periods, but determination of the specific physiological adaptation(s) underlying these performance gains requires further investigation. KEY WORDS. strength, resistance training, electromyography, coactivation

The purpose of this study was to examine the acute effects of static stretching on peak torque (PT) and mean power output (MP) during maximal, voluntary concentric isokinetic leg extensions at 60 and 300[degrees] x [s.sup.-1] in National Collegiate Athletic Association Division I Women's Basketball players. Eleven members of a women's basketball team volunteered to perform maximal concentric isokinetic leg extensions at 60 and 300[degrees].[s.sup.-1] on a calibrated Biodex System 3 dynamometer. After the initial isokinetic testing, the dominant leg extensors were stretched using 1 unassisted and 3 assisted static stretching exercises. The poststretching isokinetic assessments were repeated at 5, 15, 30, and 45 minutes after the static stretching (post-5, post-15, post-30, and post-45). PT (Nxm) and MP (W) were recorded by dynamometer software. The results indicated no stretching-related changes in PT (p = 0.161) or MP (p = 0.088) from pre- to poststretching for any of the testing intervals (post5, post-15, post-30, and post-45). These findings indicated that the static stretching had no impact on PT or MP during maximal, voluntary concentric isokinetic muscle actions in collegiate women's basketball players. In conjunction with previous studies, these findings suggested that trained athletes may be less susceptible to the stretching-induced force deficit than untrained, nonathletes. KEY WORDS. stretching-induced force deficit, isokinetic, athletes, muscle strength, velocity

The purpose of this study was to examine the acute effects of static stretching on peak torque (PT) and the joint angle at PT during maximal, voluntary, eccentric isokinetic muscle actions of the leg extensors at 60 and 180[degrees] x [s.sup.-1] for the stretched and unstretched limbs in women. Thirteen women (mean age [+ or -] SD = 20.8 [+ or -] 0.8 yr; weight [+ or -] SD = 63.3 [+ or -] 9.5 kg; height [+ or -] SD = 165.9 [+ or -] 7.9 cm) volunteered to perform separate maximal, voluntary, eccentric isokinetic muscle actions of the leg extensors with the dominant and nondominant limbs on a Cybex 6000 dynamometer at 60 and 180[degrees] x [s.sup.-1]. PT (Nm) and the joint angle at PT ([degrees]) were recorded by the dynamometer software. Following the initial isokinetic assessments, the dominant leg extensors were stretched (mean stretching time [+ or -] SD = 21.2 [+ or -] 2.0 minutes) using 1 unassisted and 3 assisted static stretching exercises. After the stretching (4.3 [+ or -] 1.4 minutes), the isokinetic assessments were repeated. The statistical analyses indicated no changes (p > 0.05) from pre- to poststretching for PT or the joint angle at PT. These results indicated that static stretching did not affect PT or the joint angle at PT of the leg extensors during maximal, voluntary, eccentric isokinetic muscle actions at 60 and 180[degrees] x [s.sup.-1] in the stretched or unstretched limbs in women. In conjunction with previous studies, these findings suggested that static stretching may affect torque production during concentric, but not eccentric, muscle actions. KEY WORDS. voluntary, eccentric isokinetic, peak torque, joint angle at peak torque, dominant, nondominant

The purpose of this study was to determine the effects of resistance training in combination with a leucine and whey protein supplement or a carbohydrate placebo on strength and muscle cross-sectional area (CSA). Thirty-three men (mean age [+ or -] SD = 22.4 [+ or -] 2.4 years) were assigned to 1 of 3 groups: (1) supplementation group (SUPP), (2) placebo group (PL), or (3) control group (CON). The SUPP and PL performed unilateral training of the leg extensor muscles with the nondominant limb for 8 weeks. The strength of each limb, muscle CSA of the quadriceps femoris (QF), and body composition were assessed pre-training and posttraining. The results indicated significant increases in strength for both limbs in the SUPP but only the trained limb in the PL. The increase in strength for the trained limb of the SUPP was greater than that for the trained limb of the PL. There was no significant increase in strength for either limb in the CON. There were significant increases in the CSA of all muscles of the QF of the trained limb for the SUPP and PL, and of the vastus lateralis of the untrained limb for the SUPP. The increases in QF CSA did not differ between the SUPP and PL. No significant CSA changes were found for either limb in the CON. There were no significant changes in body composition for the SUPP, PL, or CON. The current findings suggest that leucine and whey protein supplementation may provide an ergogenic effect which enhances the acquisition of strength beyond that achieved with resistance training and a carbohydrate placebo. KEY WORDS. amino acids, muscular strength, quadriceps femoris, strength training, cross-training, cross-education

Beck, T.W., T.J. Housh, G.O. Johnson, J.P. Weir, J.T. Cramer, J.W. Coburn, and M.H. Malek. Mechanomyographic and electromyographic responses during submaximal to maximal eccentric isokinetic muscle actions of the biceps brachii. J. Strength Cond. Res. 20(1):184-191. 2006.--The purpose of this investigation was to determine the mechanomyography (MMG) and electromyography (EMG) amplitude and mean power frequency (MPF) vs. eccentric isokinetic torque relationships for the biceps brachii muscle. Nine adults (mean [+ or -] SD age = 23.1 [+ or -] 2.9 years) performed submaximal to maximal eccentric isokinetic muscle actions of the dominant forearm flexors. After determination of isokinetic peak torque (PT), the subjects randomly performed submaximal step muscle actions in 10% increments from 10 to 90% PT. Polynomial regression analyses indicated that the MMG amplitude vs. eccentric isokinetic torque relationship was best fit with a quadratic model ([R.sup.2] = 0.951), where MMG amplitude increased from 10 to 60% PT and then plateaued from 60 to 100% PT. There were linear increases in MMG MPF ([r.sup.2] = 0.751) and EMG amplitude ([r.sup.2] = 0.988) with increases in eccentric isokinetic torque, but there was no significant change in EMG MPF from 10 to 100% PT. The results suggested that for the biceps brachii, eccentric isokinetic torque was increased to approximately 60% PT through concurrent modulation of the number of active motor units and their firing rates, whereas additional torque above 60% PT was produced only by increases in firing rates. These findings contribute to current knowledge of motor-control strategies during eccentric isokinetic muscle actions and could be useful in the design of training programs. KEY WORDS. mechanomyography, electromyography, motor-control strategies, eccentric isokinetic torque

The purpose of this study was to examine the patterns for the mechanomyographic (MMG) and electromyographic (EMG) amplitude and mean power frequency (MPF) vs. torque relationships during submaximal to maximal isometric and isokinetic muscle actions. Seven men (mean [+ or -] SD age, 22.4 [+ or -] 1.3 years) volunteered to perform isometric and concentric isokinetic leg extension muscle actions at 20, 40, 60, 80, and 100% of maximal voluntary contraction (MVC) and peak torque (PT) on a Cybex II dynamometer. A piezoelectric MMG recording sensor was placed between bipolar surface EMG electrodes on the vastus medialis. Polynomial regression and separate 1-way repeated-measures analysis of variance were used to analyze the EMG amplitude, MMG amplitude, EMG MPF, and MMG MPF data for the isometric and isokinetic muscle actions. For the isometric muscle actions, EMG amplitude ([R.sup.2] - 0.999) and MMG MPF ([R.sup.2] = 0.946) increased to MVC, mean MMG amplitude increased to 60% MVC and then plateaued, and mean EMG MPF did not change (p > 0.05) across torque levels. For the isokinetic muscle actions, EMG amplitude ([R.sup.2] = 0.988) and MMG amplitude ([R.sup.2] = 0.933) increased to PT, but there were no significant mean changes with torque for EMG MPF or MMG MPF. The different torque-related responses for EMG and MMG amplitude and MPF may reflect differences in the motor control strategies that modulate torque production for isometric vs. dynamic muscle actions. These results support the findings of others and suggest that isometric torque production was modulated by a combination of recruitment and firing rate, whereas dynamic torque production was modulated primarily through recruitment. KEY WORDS. electromyography, mechanomyography, phonomyography, acoustic myography, quadriceps

The purpose of this study was 3-fold: (a) to determine if the mathematical model used to estimate the electromyographic fatigue threshold (EM[G.sub.FT]) and physical working capacity at the heart rate threshold ([PWC.sub.HRT]) could be applied to [Vo.sub.2] measurements, (b) to propose a new fatigue threshold called the physical working capacity at the oxygen consumption threshold (PW[C.sub.Vo.sub.2]), and (c) to compare the power output at the PW[C.sub.Vo.sub.2] to those of the EM[G.sub.FT], PW[C.sub.HRT], and ventilatory threshold (VT). Fifteen adult volunteers (mean age [+ or -] SD = 22 [+ or -] 2 years) performed a maximal cycle ergometer test to determine [Vo.sub.2]peak and VT as well as 4 8-minute submaximal work bouts for the determination of PW[C.sub.HRT], EM[G.sub.FT], and PW[C.sub.Vo.sub.2]. A 1-way repeated measures analysis of variance (ANOVA) with Tukey post hoc comparison indicated that PW[C.sub.HRT] (84 [+ or -] 36) was significantly (p < 0.05) less than EM[G.sub.FT] (126 [+ or -] 51), but there were no differences for PW[C.sub.Vo.sub.2] (111 [+ or -] 44) and VT (111 [+ or -] 60) versus PW[C.sub.HRT], or EM[G.sub.FT]. The results of this study indicated that (a) the mathematical model used to determine the PW[C.sub.HRT] and EM[G.sub.FT] was applicable to the measurement of [Vo.sub.2] and could be used to estimate the PW[C.sub.Vo.sub.2] during cycle ergometry, (b) there was a difference in the mean power outputs that corresponded to the fatigue thresholds determined from EMG and heart rate measurements, and (c) the PW[C.sub.Vo.sub.2] test may provide a useful submaximal technique for estimating the VT. KEY WORDS. fatigue thresholds, EM[G.sub.FT], PW[C.sub.HRT], VT, [Vo.sub.2] slow component

The purpose of this investigation was to determine the accuracy of near-infrared interactance (NIR) instruments and population-specific NIR equations for estimating percent body fat (% fat) in young wrestlers. Forty-four white male youth wrestlers (mean age [+ or -] SD = 11.0 [+ or -] 2.1 years) volunteered for this study. Thirteen NIR % fat estimates were cross-validated against the criterion % fat from underwater weighing. The results of this study indicated that the total error (TE) values associated with the NIR instrument generated % fat estimates as well as % fat estimates from population-specific NIR equations developed for high school wrestlers or adult men were too large (TE = 5.7-27.3% fat) to be used with young wrestlers. Based on the present findings, it is recommended that new NIR equations be developed and validated specifically for use in young male athletes. KEY WORDS. percent body fat, validity, athletes

The purpose of this study was to examine the effects of static stretching on concentric, isokinetic leg extension peak torque (PT) at 60 and 240[degrees] x [s.sup.-1] in the stretched and unstretched limbs. The PT of the dominant (stretched) and nondominant (unstretched) leg extensors were measured on a calibrated Cybex 6000 dynamometer. Following the prestretching PT assessments, the dominant leg extensors were stretched using 1 active and 3 passive stretching exercises. After the stretching, PT was reassessed. The results of the statistical analyses indicated that PT decreased following the static stretching in both limbs and at both velocities (60 and 240[degrees] x [s.sup.-1]). The present findings suggested that the stretching-induced decreases in PT may be related to changes in the mechanical properties of the muscle, such as an altered length-tension relationship, or a central nervous system inhibitory mechanism. Overall, these findings, in conjunction with previous studies, indicated that static stretching impairs maximal force production. Strength and conditioning professionals should consider this before incorporating static stretching in preperformance activities. Future studies are needed to identify the underlying mechanisms that influence the time course of stretching-induced decreases in maximal force production for athletes and nonathletes across the age span. KEY WORDS. Stretching-induced, dominant, nondominant, stretched, unstretched, maximal force production

This article compares the relationships between muscle power, peak torque patterns, and mechanomyographic and electromyographic measurements among men and women.

This article discusses the relationship between muscle strength, resistance training, and mechanomyographic and electromyographic response. An analysis of muscle contraction, arm circumference, and hypertrophy is presented.