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Examined the effects of unilateral concentric isokinetic leg extension training on peak torque and electromyographic (EMG) responses in trained and untrained limbs. Adult men participated in training and control groups. Overall, unilateral concentric isokinetic strength training induced strength increases in trained as well as untrained limbs. There was no significant change in EMG amplitude in trained or untrained limbs. (SM)

Camic, CL, Hendrix, CR, Housh, T J, Zuniga, JM, Mielke, M, Johnson, GO, Schmidt, R J, and Housh, DJ. The effects of polyethylene glycosylated creatine supplementation on muscular strength and power. J Strength Cond Res 24(12): 3343-3351, 2010-The purpose of the present investigation was to examine the effects of 28 days of polyethylene glycosylated creatine (PEG-creatine) supplementation on 1-repetition maximum bench press (1RMBp) and leg extension (1RMLE), mean power (MP), and peak power (PP) from the Wingate Anaerobic test and body weight (BW). This study used a randomized, double-blind, placebo-controlled, parallel design. Twenty-two untrained men (mean age [+ or -] SD = 22.1 [+ or -] 2.1 years) were randomly assigned to either a Creatine (n = 10) or Placebo (n = 12) group. The Creatine group ingested PEG-creatine (5 [g*d.sub.-1]), whereas the Placebo group ingested maltodextrin powder (5 [g*d.sub.-1]). All subjects performed bench press and bilateral leg extension exercises to determine their 1RM values, and 2 consecutive Wingate Anaerobic Tests (separated by 7 minutes) on a cycle ergometer to determine MP and PP before supplementation (day 0) and after 7 (day 7) and 28 (day 28) days of supplementation. The results indicated that there was a significant (p < 0.05) increase in 1R[M.sub.BP] between days 0 and 28 for the Creatine group but not for the Placebo group. There were no significant changes, however, in 1R[M.sub.LE], MP, PP, or BW for the Creatine or Placebo group. These findings indicated that 28 days of PEG-creatine supplementation without resistance training increased upper body strength but not lower body strength or muscular power. These findings supported the use of the PEG-creatine supplement for increasing 1R[M.sub.BP] strength in untrained individuals. KEY WORDS PEG, 1 repetition maximum, supplements, bench press, leg extension

Camic, CL, Housh, TJ, Weir, JP, Zuniga, JM, Hendrix, CR, Mielke, M, Johnson, GO, Housh, DJ, and Schmidt, RJ. Influences of body-size variables on age-related increases in isokinetic peak torque in young wrestlers. J Strength Cond Res 24(9): 2358-2365, 2010--The purposes of the present study were to determine the patterns of age-related changes in 1) height (HT), body weight (BW), fat-free weight (FFW), and absolute isokinetic peak torque (PT); and 2) isokinetic PT covaried separately for HT, BW, FFW, and HT and BW combined in young wrestlers. One hundred twenty-five male wrestlers (mean age [+ or -] SD = 14.3 [+ or -] 2.4 yr; range = 11.1-18.2 yr) volunteered to perform concentric, isokinetic leg extension and flexion at 180[degrees] x [s.sup.-1] on a Cybex II dynamometer to measure PT as well as underwater weighing to determine FFW. The polynomial regression analyses indicated there were significant quadratic increases across age for HT ([R.sup.2] = 0.62), BW ([R.sup.2] = 0.56), and FFW ([R.sup.2] = 0.47). For leg extension, there were significant increases across age for absolute PT (quadratic, [R.sup.2] = 0.66), PT covaried for HT (linear, [r.sup.2] = 0.10), PT covaried for BW (linear, [r.sup.2] = 0.12), PT covaried for FFW (quadratic, [R.sup.2] = 0.32), and PT covaried for HT and BW combined (quadratic, [R.sup.2] = 0.11). For leg flexion, there were significant increases across age for absolute PT (linear, [r.sup.2] = 0.59), PT covaried for HT (linear, [r.sup.2] = 0.07), PT covaried for BW (linear, [r.sup.2] = 0.08), PT covaried for FFW (quadratic, [R.sup.2] = 0.23), and PT covaried for BW and HT combined (linear, [r.sup.2] = 0.03). The results of this study indicated that age-related increases in leg-extension and flexion PT for the current sample of young wrestlers could not be accounted for by changes in HT, BW, FFW, or HT and BW combined. These findings suggested that neural maturation may contribute to increases in leg strength across age in young wrestlers. KEY WORDS strength, athletes, growth, maturation, neuromuscular

The purpose of the present study was to examine the acute effects of a caffeine-containing supplement (SUPP) on 1 repetition maximum (1 RM) bench press and leg extension strength, as well as time to exhaustion (TTE), during cycle ergometry at a power output that corresponded to 80% of [??][o.sub.2]peak. The study used a double-blinded, placebo-controlled, crossover design. Twenty-one untrained men (mean [+ or -] SD age = 23.0 [+ or -] 2.6 yr) were randomly assigned to take either the SUPP or placebo (PLAC) first. The SUPP contained 400 mg of caffeine, 66.7 mg of capsicum extract, 10 mg of bioperine, and 40 mg of niacin, and the PLAC was microcrystalline cellulose. Sixty minutes after taking either the SUPP or PLAC, the subjects were tested for 1RM bench press and leg extension strength, as well as TTE. After 1 week of rest, the subjects ingested the opposite substance (SUPP or PLAC) and were retested for 1 RM bench press and leg extension strength, as well as TTE. The results indicated that the SUPP had no effect on 1RM bench press strength, 1 RM leg extension strength, or TTE at 80% [??][o.sub.2]peak. These findings did not support the use of the caffeine-containing SUPP in the present study as an ergogenic aid in untrained individuals. KEY WORDS endurance

The purposes of this study were to 1) compare the patterns of responses for plasma ammonia concentration ([N[H.sub.3]]) during moderate- vs. heavy-intensity cycle ergometry, and 2) examine the relationship between the [Vo.sub.2] slow component ([Vo.sub.2SC]) and plasma [N[H.sub.3]]. Thirteen healthy, untrained men (mean [+ or -] SEM age = 24.8 [+ or -] 0.6 years) performed a total of eight constant power output exercises (7 minutes in duration) at two different intensities (moderate, 60% gas exchange threshold [GET] = 60% of the gas exchange threshold; and heavy, [DELTA]50% = 50% of the difference between GET and [Vo.sub.2]max). Blood was collected from an antecubital vein before the exercise, during the last 3 minutes of the 6-minute warm-up, and during each minute of the 7-minute constant power output workbout. The time course of changes in plasma [N[H.sub.3]] and [Vo.sub.2] during the two constant power output exercise intensities were assessed separately using 2 (intensity) x 7 (time) repeated-measures analyses of variance. For 60% GET, there were no significant differences in the mean normalized plasma [N[H.sub.3]] during the 7-minute workbout. For [DELTA]50%, there was a significant increase in the mean normalized plasma [N[H.sub.3]] during the 7-minute workbout. These findings suggest a potential relationship between exercise-induced hyperammonemia and the [Vo.sub.2SC] during heavy-intensity exercise. KEY WORDS ammonia concentration, AMP deaminase, bioenergetics, muscle energetics, oxygen uptake kinetics

The purpose of this study was to examine the effects of daily administration of a supplement that contained caffeine in conjunction with 8 weeks of aerobic training on [Vo.sub.2]peak, time to running exhaustion at 90% [Vo.sub.2]peak, body weight, and body composition. Thirty-six college students (14 men and 22 women; mean [+ or -] SD, age 22.4 [+ or -] 2.9 years) volunteered for this investigation and were randomized into either a placebo (n = 18) or supplement group (n = 18). The subjects ingested 1 dose (3 pills = 201 mg of caffeine) of the placebo or supplement per day during the study period. In addition, the subjects performed treadmill running for 45 minutes at 75% of the heart rate at [Vo.sub.2]peak, three times per week for 8 weeks. All subjects were tested pretraining and posttraining for [Vo.sub.2]peak, time to running exhaustion (TRE) at 90% [Vo.sub.2]peak, body weight (BW), percentage body fat (%FAT), fat weight (FW), and fat-free weight (FFW). The results indicated that there were equivalent training-induced increases (p < 0.05) in [Vo.sub.2]peak and TRE for the supplement and placebo groups, but no changes (p > 0.05) in BW, %FAT, FW, or FFW for either group. These findings indicated that chronic use of the caffeine-containing supplement in the present study, in conjunction with aerobic training, provided no ergogenic effects as measured by [Vo.sub.2]peak and TRE, and the supplement was of no benefit for altering body weight or body composition. KEY WORDS. aerobic power, maximal oxygen uptake, nutrition, supplements, treadmill exercise

The purpose of this study was to examine the acute effects of a caffeine-containing supplement on upper- and lower-body strength and muscular endurance as well as anaerobic capabilities. Thirty-seven resistance-trained men (mean [+ or -] SD, age: 21 [+ or -] 2 years) volunteered to participate in this study. On the first laboratory visit, the subjects performed 2 Wingate Anaerobic Tests (WAnTs) to determine peak power (PP) and mean power (MP), as well as tests for I repetition maximum (1RM), dynamic constant external resistance strength, and muscular endurance (TOTV; total volume of weight lifted during an endurance test with 80% of the 1RM) on the bilateral leg extension (LE) and free-weight bench press (BP) exercises. Following a minimum of 48 hours of rest, the subjects returned to the laboratory for the second testing session and were randomly assigned to I of 2 groups: a supplement group (SUPP; n = 17), which ingested a caffeine-containing supplement, or a placebo group (PLAC; n = 20), which ingested a cellulose placebo. One hour after ingesting either the caffeine-containing supplement or the placebo, the subjects performed 2 WAnTs and were tested for 1RM strength and muscular endurance on the LE and BP exercises. The results indicated that there was a significant (p < 0.05) increase in BP 1RM for the SUPP group, but not for the PLAC group. The caffeine-containing supplement had no effect, however, on LE 1RM, LE TOTV, BP TOTV, PP, and MP. Thus, the caffeine-containing supplement may be an effective supplement for increasing upper-body strength and, therefore, could be useful for competitive and recreational athletes who perform resistance training. Key Words. ergogenic aid, performance, sports nutrition

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

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 cross-validate the fat-free weight (FFW) equations derived on nonathletic children and adolescents for estimating mean power (MP) and peak power (PP) in high school wrestlers. One hundred and three male high school wrestlers performed the Wingate Anaerobic Test to estimate MP and PP, as well as underwater weighing to determine FFW. The follow equations were used to estimate the MP and PP of the wrestlers in the current study. MP (W) = 9.3 (FFW) 109.8 - EQ.1 PP (W) = 14.1 (FFW) 162.1 - EQ.2 The results in the current study indicated that as percent of the mean values, the equation that predicted MP resulted in a substantially greater total error (TE; 19.9% of the mean) than the equation that predicted PP (8.3% of the mean). These findings indicated that the equation that was derived on nonathletes did not accurately estimate MP in the high school wrestlers. The equation for estimating PP, however, was valid when applied to the current sample of high school wrestlers. These findings supported previous studies that have shown that in adolescent males, exercise training improves the metabolic capabilities of the anaerobic glycolytic system, but not the phosphagen system. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to determine the validity of near-infrared interactance (NIR) estimates of percent body fat (% fat) using Futrex-5000, Futrex-5000A, and Futrex-1000 instruments in youth wrestlers (age, M ± SD = 11.4 ± 1.5 years) by comparing them to % fat values from underwater weighing. Fifty-eight members of youth wrestling clubs (% fat, M ± SD = 10.7 ± 5.1% fat) volunteered to serve as subjects. The statistical analyses included examination of the constant error (CE), standard error of estimate (SEE), correlation coefficient (r), and total error (TE). The results indicated that the errors (TE = 8.0-16.2% fat) associated with the NIR instruments were too large to be of practical value for estimating % fat in young male athletes. It is recommended that (a) the instrument generated NIR % fat estimates be modified based on the CE values in the present investigation such that the CE = 0, and (b) the modified NIR % fat estimates be cross-validated on independent samples of young male athletes. [ABSTRACT FROM AUTHOR]

The purpose of this investigation was to examine age related changes in muscular power of high school wrestlers. A total of 155 high school wrestlers (M age ± SD = 16.5 ± 2.4 yrs) volunteered as subjects for this investigation. The sample included only wrestlers who were ≤ 16.00 years (younger group, n = 75) or >17.00 years (older group, n = 80). All subjects completed a Wingate anaerobic test to determine mean (MP) and peak (PP) power as well as underwater weighing for body composition assessment. The results indicated significant (p<0.05) group differences for absolute MP and PP but no differences when adjusted for BW and FFW. Thus the enhanced muscular power in the older group of high school wrestlers was associated with increases in BW and FFW. [ABSTRACT FROM AUTHOR]

The purpose of this investigation was twofold: (a) to determine the validity of high school wrestlers' estimations of minimal wrestling weight (MWW) and (b) to compare their certified wrestling weight with the recommended MWW values based on underwater weighing (fat-free weight plus 5% fat). Sixty wrestlers (M age&plsmn;SD=16.54&plsmn;1.07 yrs) volunteered to be assessed via underwater weighing and were asked to estimate, within 1 lb, their MWW. The certified wrestling weight for each subject was also obtained from the state activities association. The results indicated that the total error for the wrestlers' estimations of MWW ranged from 3.25 to3.69 kg, and in 32 to 43% of the cases the certified wrestling weight was below (M=2.29−2.84 kg) the recommended MWW from underwater weighing. [ABSTRACT FROM AUTHOR]

The purpose of this investigation was to examine age-related differences in absolute and relative isokinetic shoulder strength of high school wrestlers. A total of 122 high school wrestlers (M age = 16.31 ± 1.18 yrs) volunteered to be measured for arm flexion and extension strength at the shoulder joint using a Cybex II dynamometer at 30, 180, and 300°•s-1. The sample was divided into four age groups: 13.75-15.00 (n=22), 15.08-16.00 (n=27), 16.08-17.00 (n=34), and 17.08-18.83 years (n=39). The results of this study indicated significant increases in absolute and relative arm flexion and extension strength across age when covaried for BW and FFW. In addition, comparisons with previously published data indicated differences between muscle groups in the pattern of strength gains that were dependent upon the speed of muscular contraction and may have been influenced by fiber type distribution characteristics. [ABSTRACT FROM AUTHOR]