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Rubber-based resistance (RBR) bands and standard link steel (SLS) chains are 2 forms of variable resistance used throughout the strength and conditioning and rehabilitation communities. The purpose of this study was to quantify the tension of RBR bands and the mass of SLS chains as a function of displacement (increasing in 10-cm increments). Five sets of RBR bands (14-, 22-, 30-, 48-, and 67-mm widths) and 5 sets of SLS chains (6-, 8-, 10-, 13-, 16-mm diameters) were measured using a load cell and a force plate. The RBR bands exhibited curvilinear tension-deformation relationships and were best represented ([R.sup.2] greater than or equal to] 0.99) by second-order polynomial functions, whereas the SLS chains exhibited linear mass-displacement relationships and were best represented ([R.sup.2] = 1) by first-order polynomial functions. There were no significant differences (p > 0.05) in force outputs between the load cell and the force plate testing, although the strain gauge is a relatively cheap and viable method of quantifying the variable resistance of chains and bands. The strength and conditioning practitioner when purchasing bands needs to be aware of resting length differences (3.5-5.2%), which resulted in mean tension imbalances of 8-19% in the same color band. This study provides the strength and conditioning coach and clinician with a methodology to quantify variable resistance, which may be useful in the prescription of specific loading intensities. KEY WORDS material properties, standard link steel chains, variable resistance, biomechanics

Nonselective blockade of the cyclooxygenase (COX) enzymes in skeletal muscle eliminates the normal increase in muscle protein synthesis following resistance exercise. The current study tested the hypothesis that this COX-mediated increase in postexercise muscle protein synthesis is regulated specifically by the COX-2 isoform. Sixteen males (23 [+ or -] 1 yr) were randomly assigned to one of two groups that received three doses of either a selective COX-2 inhibitor (celecoxib; 200 rag/dose, 600 mg total) or a placebo in double-blind fashion during the 24 h following a single bout of knee extensor resistance exercise. At rest and 24 h postexercise, skeletal muscle protein fractional synthesis rate (FSR) was measured using a primed constant infusion of [[sup.2][H.sub.5]]phenylalanine coupled with muscle biopsies of the vastus lateralis, and measurements were made of mRNA and protein expression of COX-1 and COX-2. Mixed muscle protein FSR in response to exercise (P < 0.05) was not suppressed by the COX-2 inhibitor (0.056 - 0.004 to 0.108 -+ 0.014%/h) compared with placebo (0.074 _+ 0.004 to 0.091 -+ 0.005%/h), nor was there any difference (P > 0.05) between the placebo and COX-2 inhibitor postexercise when controlling for resting FSR. The COX-2 inhibitor did not influence COX-1 mRNA, COX-1 protein, or COX-2 protein levels, whereas it did increase (P < 0.05) COX-2 mRNA (3.0 [+ or -] 0.9-fold) compared with placebo (1.3 _+ 0.3-fold). It appears that the elimination of the postexercise muscle protein synthesis response by nonselective COX inhibitors is not solely due to COX-2 isoform blockade. Furthermore, the current data suggest that the COX-1 enzyme is likely the main isoform responsible for the COX-mediated increase in muscle protein synthesis following resistance exercise in humans. celecoxib; [sup.2][H.sub.5] phenylalanine; resistance exercise doi: 10.1152/ajpendo.00423.2009

There has been considerable debate over the optimal number of sets per exercise to improve musculoskeletal strength during a resistance exercise program. The purpose of this study was to use hierarchical, random-effects meta-regression to compare the effects of single and multiple sets per exercise on dynamic strength. English-language studies comparing single with multiple sets per exercise, while controlling for other variables, were considered eligible for inclusion. The analysis comprised 92 effect sizes (ESs) nested within 30 treatment groups and 14 studies. Multiple sets were associated with a larger ES than a single set (difference = 0.26 [+ or -] 0.05; confidence interval [CI]: 0.15, 0.37; p < 0.0001). In a dose-response model, 2 to 3 sets per exercise were associated with a significantly greater ES than 1 set (difference = 0,25 [+ or -] 0.06; CI: 0.14, 0.37; p [+ or -] 0.0001). There was no significant difference between 1 set per exercise and 4 to 6 sets per exercise (difference = 0.35 [+ or -] 0.25; CI: -0.05, 0.74; p = 0.17) or between 2 to 3 sets per exercise and 4 to 6 sets per exercise (difference = 0.09 [+ or -] 0.20; CI: -0.31, 0.50; p = 0.64). There were no interactions between set volume and training program duration, subject training status, or whether the upper or lower body was trained. Sensitivity analysis revealed no highly influential studies, and no evidence of publication bias was observed. In conclusion, 2 to 3 sets per exercise are associated with 46% greater strength gains than 1 set, in both trained and untrained subjects. KEY WORDS meta-analysis, effect size, dynamic strength, volume

Pantoja, PD, Alberton, CL, Pilla, C, Vendrusculo, AP, and Kruel, LFM. Effect of resistive exercise on muscle damage in water and on land. J Strength Cond Res 23(3): 1051-1054, 2009--The purpose of this study was to compare the effects of resistance exercise in water and on land on blood levels of creatine kinase (CK), a known indirect marker of muscle damage. Nine men (age: 23 [+ or -] 1.58 years; weight: 79.37 [+ or -] 11.15 kg; height: 176.33 [+ or -] 4.09 cm), who had not practiced resistance training for at least 6 months before this experiment, performed 3 sets of maximum elbow flexion and extension exercises in water and on land, separated by 2-minute periods of rest. A 10-repetition maximum test was used to load control on land with free weights, and in water the exercise was performed at maximum velocity with aquatic resistance equipment. The duration of the exercise in water was the same as that performed on land, to reproduce the same metabolic route. Plasma CK activity was determined using a commercially available kit (Labtest Enzymatic-UV) before exercise, after exercise, and at 24 and 48 hours after exercise. Significant increases in CK were found at 48 hours postexercise on land (preexercise land: 160.75 [+ or -] 96.05 U x [L.sup.-1]; 48 hours: 326.87 [+ or -] 240.84 U x [L.sup.-1]), and significant differences were found between land and water (preexercise water: 147.75 [+ or -] 46.48 U x [L.sup.-1] 48 hours:121.75 [+ or -] 30.86 U x [L.sup.-1]) for this measure. However, no significant differences were found in water. In conclusion, the water environment influenced the absence of significant muscle damage. This type of exercise protocol may be appropriate for situations in which limited muscle tissue damage is desired. KEY WORDS creatine kinase, aquatic environment, elbow flexors

The main objective of this study was to compare electromyography (EMG), heart rate (HIR), and perceived exertion (PE) during different elbow flexion exercises in standing position (biceps curl [BC] and adapted BC [ABC]) and seated position (preacher BC [PBC]). Twenty healthy subjects performed the dynamic 1-repetition maximum (1RM) test. The following week (1 exercise per day), these exercises were performed at 25, 30, 35, and 40% 1RM at 1 minute for each one (20 repetitions). Biceps brachii and brachioradialis root mean square (RMS), HR, and PE were recorded in the 5th (R5), 10th (R10), 15th (R15), and 20th (R20) repetitions. Effects of exercise type (BC x ABC x PBC), load level(25% 1RM x 30% 1RM x 35% 1RM x 40% 1RM), and exercise duration (R5 x R10 x R15 x R20) were analyzed. The RMS of the elbow flexors in the PBC R20 was significantly lower than BC and ABC at 40% 1RM, and, in the same way, for all load levels, HR and PE were significantly lower in PBC R20 at 40% 1RM compared with BC and ABC. For all exercises, RMS, HR, and PE at 25% 1RM were significantly lower than at 40% 1RM. The execution of the exercises caused significant increases in the RMS, HR, and PE mainly between R5 compared with R15 and R20. In conclusion, different positions demand different neuromuscular (EMG), cardiovascular (HR), and sensorial (PE) responses. A decreased effort sensation in PBC at the same relative load level can contribute to better execution when standing and seated exercises are compared. KEY WORDS electromyography, muscular fatigue, perceived exertion, heart rate

Various studies have demonstrated that resistance sprint (RS) training can produce significant changes in running speed and running kinematics. The longer-term training adaptations after RS training remain unclear. The purpose of this study was to investigate whether an RS training intervention would enhance the running speed and dynamic strength measures in male rugby players. Fifteen male rugby players aged 20.5 ([+ or -] 2.8) years who were proficient in resisted sledge training took part in the study. The subjects were randomly assigned to control or RS groups. The RS group performed two sessions per week of RS training for 6 weeks, and the control group did no RS training. Pre- and postintervention tests were carried out for 30-m sprint, drop, squat, and rebound jumps on a force sledge system. A laser measurement device was used to obtain velocities and distance measures during all running trials. The results show a statistically significant decrease in time to 5 m for the 30-m sprint for the RS group (p = 0.02). The squat jump and drop jump variables also showed significant increases in starting strength (p = 0.004) and height jumped (p = 0.018) for the RS group from pre- to posttesting sessions. The results suggest that it may be beneficial to employ an RS training intervention with the aim of increasing initial acceleration from a static start for sprinting. Key Words resistance training, acceleration, rate of force development, drop jump, sledge, laser

The purpose of this study was to examine the efficacy of periodization and to compare different periodization models in resistance trained American football players. Fifty-one experienced resistance trained American football players of an NCAA Division III football team (after 10 weeks of active rest) were randomly assigned to 1 of 3 groups that differed only in the manipulation of the intensity and volume of training during a 15-week off-season resistance training program. Group 1 participated in a nonperiodized (NP) training program, group 2 participated in a traditional periodized linear (PL) training program, and group 3 participated in a planned nonlinear periodized (PNL) training program. Strength and power testing occurred before training (PRE), after 7 weeks of training (MID), and at the end of the training program (POST). Significant increases in maximal (1-repetition maximum [1RM]) squat, 1RM bench press, and vertical jump were observed from PRE to MID for all groups; these increases were still significantly greater at POST; however, no MID to POST changes were seen. Significant PRE to POST improvements in the medicine ball throw (MBT) were seen for PL group only. The results do not provide a clear indication as to the most effective training program for strength and power enhancements in already trained football players. Interestingly, recovery of training-related performances was achieved after only 7 weeks of training, yet further gains were not observed. These data indicate that longer periods of training may be needed after a long-term active recovery period and that active recovery may need to be dramatically shortened to better optimize strength and power in previously trained football players. Key Words American football, athletes, power, strength training

Hollander, DB, Kilpatrick, MW, Ramadan, ZG, Reeves, GV, Francois, M, Blakeney, A, Castracane, VD, and Kraemer, RR. Load rather than contraction type influences rate of perceived exertion and pain. J Strength Cond Res 22: 1184-1193, 2008--The purpose of the study was to determine whether muscle contraction type (concentric [CON] or eccentric [ECC]) or loading (relative or absolute) has a greater impact on the perceptual and metabolic responses to conventional resistance exercise. Additionally, overall effort, pain sensations, and specific pain descriptors were compared with physiological responses. Seven healthy men (mean [+ or -] SE, 25.71 [+ or -] 2.17 years) with resistance training experience completed 2 one-repetition maximum (1-RM) trials. Subsequently, 2 randomized, counterbalanced, experimental sessions were completed consisting of 4 sets of 10 repetitions for 6 exercises. These sessions were performed at 65% CON 1-RM for CON only contractions or 65% CON 1-RM + 20% for ECC contractions. Blood samples were taken pre, post, and 15 minutes postexercise. OMNI-RPE (OMNI-Res), CR-10 pain rating, McGill pain ratings, and heart rate (HR) were recorded after each set. A significant time effect occurred for OMNI-Res, pain, lactate, and HR (p < 0.05). No significant pattern emerged for the contraction type, except for higher HR and lactate immediately postexercise for the CON contractions. Physiological measures were not significantly related to perceptual measures. When considered with previous data, muscle loading rather than contraction type plays the primary role in perceptual alterations of effort sense and pain. Practical applications of the investigation are that strength and conditioning professionals may be able to load CON and ECC contractions in a relative fashion by increasing loads in the ECC portion by 20% above the CON load that would result in comparable perceptual experiences. KEY WORDS OMNI-Res, eccentric, concentric, McGill Pain Questionnaire

Previous research has shown that L-carnitine L-tartrate (LCLT) supplementation beneficially affects markers of hypoxic stress following resistance exercise. However, the mechanism of this response is unclear. Therefore, the primary purpose of this study was to determine the effects of LCLT supplementation on muscle tissue oxygenation during and after multiple sets of squat exercise. Nine healthy, previously resistancetrained men (25.2 [+ or -] 6 years, 91.2 [+ or -]10.2 kg, 180.2 [+ or -] 6.3 cm) ingested LCLT (equivalent to 2g L-Carnitine/day) or an identical placebo for 23 days using a randomized, balanced, crossover, double-blind, placebo-controlled, repeated-measures study design. On day 21, forearm muscle oxygenation was measured during and after an upper arm occlusion protocol using near infrared spectroscopy (NIRS), which measures the balance of oxygen delivery in relation to oxygen consumption. On day 22, subjects performed 5 sets of 15 to 20 repetitions of squat exercise with corresponding measures of thigh muscle oxygenation, via NIRS, and serial blood draws. Compared to the placebo trial, muscle oxygenation was reduced in the LCLT trial during upper arm occlusion and following each set of resistance exercise. Despite reduced oxygenation, plasma malondealdehyde, a marker of membrane damage, was attenuated during the LCLT trial. There were no differences between trials in the vasoactive substance prostacyclin. In conclusion, because oxygen delivery was occluded during the forearm protocol, it is proposed that enhanced oxygen consumption mediated the reduced muscle oxygenation during the LCLT trial. Enhanced oxygen consumption would explain why hypoxic stress was attenuated with LCLT supplementation. KEY WORDS ergogenic aids, metabolic stress, performance, recovery, supplements

To assess unloaded knee extensor temporal strength changes, healthy subjects without asthma performed 40 continuous days of unilateral limb suspension, whereby their left leg refrained from normal weight-bearing and ambulatory activity. During the 40-day period, subjects performed resistance exercise (REX) with their unloaded leg on an inertial resistance ergometer and, as part of a double-blind design, consumed the maximal oral therapeutic dosage of albuterol (i.e., 16 mg*[d.sup.-1]) or a placebo (i.e., lactose) with no crossover. Workout data were partitioned into 4 10-day periods that ran consecutively. Dependent strength variables included concentric total work, eccentric total work, concentric average power (CAP), and eccentric average power (EAP). Dependent variables were analyzed with 5 (time) x 2 (group) x 2 (gender) mixed factorial analyses of variance and the Tukey honestly significant difference test. Concentric total work, CAP, and EAP each demonstrated a time--group--gender (p < 0.05) interaction. Female REX-placebo subjects had the greatest percentage of unloaded knee extensor strength loss. However, female REX--albuterol subjects fared best throughout the 40-day period and incurred significant unloaded knee extensor strength gains. Differences in strength changes between male and female REX--albuterol subjects was likely due to the higher relative dosage administered to the latter, as body mass showed a gender (i.e., men > women) effect. Future research may elucidate the ideal dose-response relationship for REX--albuterol treatment for use aboard manned space flights and in other disuse models. Coaches and practitioners should carefully examine their sport-governing bodies' rules on albuterol administration and give the drug only if an athlete's health warrants such treatment. KEY WORDS concentric; eceentriei [[beta].sub.2] agonists

The purpose of the present investigation was to examine the influence of resistance training with a personal trainer versus unsupervised resistance training on the self-selected intensities used by women during resistance exercise. Forty-six resistance-trained women (age = 26.6 [+ or -] 6.4 years; body mass = 64.2 [+ or -] 10.9 kg) who either trained individually (n = 27; No PT) or with a personal trainer (n = 19; PT) were carefully instructed to select a weight they used in their own resistance training workouts that enabled the completion of 10 repetitions for the chest press (CP), leg press (LP), seated row (SR), and leg extension (LE) exercises. Each participant was subsequently tested for one repetition-maximum (1RM) strength on each exercise, and the self-selected intensity was calculated based on a percent of each 1RM value. For self-selected relative intensity, the PT group selected significantly greater intensities for LP (50% vs. 41%), CP (57.4% vs. 48%), and SR (56% vs. 42%) whereas a trend (p = 0.10) was observed for LE (43% vs. 38%) compared with No PT. Overall, the average self-selected intensity for all exercises was ~51.4% in PT group and ~42.3% in the No PT group. 1RM values for LP, LE, and SR were greater in the PT than No PT group. Ratings of perceived exertion values were significantly greater in the PT compared with the No PT group for CP, LE, and SR but not LP. These results indicate that resistance training under the supervision of a personal trainer leads to greater initial 1RM strength values, self-selection of greater workout intensities, and greater ratings of perceived exertion values during resistance exercise. KEY WORDS muscular strength, ratings of perceived exertion, strength training, fitness

The purpose of the present study was to examine the effect of heating and cooling the forearm muscles on renal vascular responses to ischemic isometric handgrip (IHG). It was hypothesized that heating and cooling the forearm would augment and attenuate, respectively, renal vascular responses to IHG. Renal vascular responses to IHG were studied during forearm heating at 39[degrees]C (n = 15, 26 [+ or -] 1 yr) and cooling at 26[degrees]C (n = 12, 26 [+ or -] 1 yr). For a control trial, subjects performed the experimental protocol while the forearm was normothermic (~34[degrees]C). Muscle temperature (measured by intramuscular probe) was controlled by changing the temperature of water cycling through a water-perfused sleeve. The experimental protocol was as follows: 3 min at baseline, 1 min of ischemia, ischemic IHG to fatigue, and 2 min of postexercise muscle ischemia. At rest, renal artery blood velocity (RBV; Doppler ultrasound) and renal vascular conductance (RVC = RBV/mean medal blood pressure) were not different between uormothermia and the two thermal conditions. During ischemic IHG, there were greater decreases in RBV and RVC in the heating trial. However, RBV and RVC were similar during postexercise muscle ischemia during heating and normothermia. RVC decreased less during cooling than in normothermia while the subjects performed the ischemic IHG protocol. During postexercise muscle ischemia, RVC was greater during cooling than in normothermia. These results indicate that heating augments mechanoreceptor-mediated renal vasoconstriction whereas cooling blunts metaboreceptor-mediated renal vasoconstriction. cold; heat; exercise pressor reflex; sympathetic

We examined the effects of 35 and 90 days of simulated microgravity with or without resistance-exercise (RE) countermeasures on the content of the general skeletal muscle protein fractions (mixed, sarcoplasmic, and myofibrillar) and specific proteins that are critical for muscle function (myosin, actin, and collagen). Subjects from two studies, using either unilateral lower limb suspension (ULLS) or bed rest (BR), comprised four separate groups: 35 days ULLS (n = 11), 35 days ULLS+RE (n = 10), 90 days BR (n = 9), and 90 days BR+RE (n = 8). RE consisted of four sets of seven maximal concentric and eccentric repetitions of the quadriceps femoris muscles that were performed 2 or 3 times per week. Pre- and post-simulated weightlessness muscle biopsies were analyzed from the vastus lateralis of all groups and the soleus of the 35-day ULLS and 90-day BR groups. The general protein fractions and the specific proteins myosin, actin, and collagen of the vastus lateralis were unchanged (P > 0.05) in both control and countermeasures groups over 35 and 90 days, despite large changes in quadriceps femoris muscle volume (35 days ULLS: -9%, 35 days ULLS+RE: +8%; and 90 days BR: -18%, 90 days BR+RE: -1%). The soleus demonstrated a decrease in mixed (35 days ULLS: -12%, P = 0.0001:90 days BR: -12%, P = 0,004) and myofibrillar (35 days ULLS: -12%, P = 0.009:90 days BR: -8%, P = 0.04) protein, along with large changes in triceps surae muscle volume (35 days ULLS: -11%; 90 days BR: -29%). Despite the loss of quadriceps femoris muscle volume or preservation with RE countermeasures during simulated microgravity, the quadriceps femoris muscles are able to maintain the concentrations of the general protein pools and the main contractile and connective tissue elements. Soleus muscle protein composition appears to be disproportionately altered during long-duration simulated weightlessness. bed rest: spaceflight; resistance exercise: myosin; actin: collagen

We investigated the effect the loss of the CAT-2 gene (CAT-2-/-) has on lung resistance ([R.sub.L]) and tracheal isometric tension. The [R.sub.L] of CAT-2-/- mice at a maximal dose of acetylcholine (ACh) was decreased by 33.66% (P = 0.05, n = 8) compared with that of C57BL/6 (B6) mice. The isometric tension of tracheal rings from CAT-2-/- mice showed a significant decrease in carbachol (CCh)-induced force generation (33.01%, P < 0.05, n = 8) compared with controls. The isoproterenol- or the sodium nitroprusside-induced relaxation was not affected in tracheal rings from CAT-2-/- mice. The activity of iNOS and arginase in lung tissue lysates of CAT-2-/- mice was indistinguishable from that of B6 mice. Furthermore, the expression of phospholipase-C[beta] (PLC-[beta]) and phosphatidylinositol-(4)-phosphate-5-kinase-[gamma] (PIP-5K-[gamma]) was examined in the lung tissue of CAT-2-/- and B6 mice. The expression of PIP-5K-[gamma] but not PLC-[beta] was significantly reduced in CAT-2-/- compared with B6 mice. The reduced airway smooth muscle (ASM) contractility to CCh seen in the CAT-2-/- tracheal rings was completely reversed by pretreating the rings with 100 [micro]M spermine. This increase in the CAT-2-/- tracheal ring contraction upon spermine pretreatment correlated with a recovery of the expression of PIP-5K-[gamma]. Our data indicates that CAT-2 exerts control over ASM force development through a spermine-dependent pathway that directly correlates with the expression level of PIP-5K-[gamma] in the lung. lung resistance; tracheal isometric tension

The three-dimensional Computerized Isometric Strength Measurement System (CISMS) reliably and accurately measures isometric pull and push strengths in workspaces of paraplegic populations while anticipating comparative studies with other populations. The main elements of the system were: an extendable arm, a vertical supporting track, a rotating platform, a force transducer, stability sensors and a computerized data collection interface. The CISMS with minor modification was successfully used to measure isometric push-up and pull-down strengths of paraplegics and isometric push, pull, push-up and pull-down strength in workspaces for seated and standing able-bodied populations. The instrument has satisfied criteria of versatility, safety and comfort, ease of operation, and durability. Results are accurate within 2N for aligned forces. Costing approximately $1,500 (US) including computer, the system is affordable and accurate for aligned isometric strength measurements. Keywords: Isometric strength measurement system; Isometric push, pull, push-up and pull-down strengths; Computerized data collection

In order to investigate the effects of a resistance training modality on cycling performance, 23 trained club-level cyclists were placed into high resistance/low repetition (H-Res), low resistance/high repetition (H-Rep), or cycling-only groups for a 10-week program. All 3 groups followed the same cycling plan, but the H-Res and H-Rep groups added resistance training. Testing pre and post consisted of a graded incremental lactate profile test on an ergometer, with blood lactate being sampled. [VO.sub.2] values were measured to determine economy. Maximum strength testing of 4 strength exercises targeting the lower extremity musculature was conducted with the H-Res and H-Rep groups. There were significant gains in all 4 resistance training exercises (p < 0.05) for both H-Res and H-Rep, with the H-Res group having significantly greater gains than the H-Rep group had in the leg press exercise (p < 0.05). There were, however, no significant group x training differences (p > 0.05) found between the 3 training groups on the cycling test in lactate values or economy. It appears that for this population of cyclists, neither H-Res nor H-Rep resistance training provided any additional performance benefit in a graded incremental cycling test when compared with cycling alone over a training time of this length. It is possible that with this population, various factors such as acute fatigue, strength, and aerobic gains from the cycling training, in addition to well-developed bases of strength and conditioning from previous training, reduced differences between groups in both strength gains and cycling performance. KEY WORDS. cycling, strength training, economy, endurance, lactate, [VO.sub.2]

The purpose of the present investigation was to examine strength performance of 6 common resistance training exercises using free weight bars of different thickness. Eleven resistance-trained men (8.2 [+ or -] 2.6 years of experience; age: 22.1 [+ or -] 1.6 years; body mass: 90.5 [+ or -] 8.9 kg) underwent 1 repetition maximum (1RM) strength testing on 6 occasions in random order for the deadlift, bent-over row, upright row, bench press, seated shoulder press, and arm curl exercises under 3 conditions using: (a) a standard Olympic bar (OL), (b) a 2-inch thick bar (5.08 cm grip span), and (c) a 3-inch thick bar (7.62 cm grip span). Significant (p < 0.05) interactions were observed for the 'pulling' exercises. For the deadlift and bent-over row, highest 1RM values were obtained with OL, followed by the 2- and 3-inch bar. Significant 1RM performance decrements for the 2and 3-inch bars were ~28.3 and 55.0%, respectively, for the deadlift; decrements for the 2- and 3-inch bars were ~8.9 and 37.3%, respectively, for the bent-over row. For the upright row and arm curl, similar 1RMs were obtained for OL and the 2-inch bar. However, a significant performance reduction was observed using the 3-inch bar (~26.1% for the upright row and 17.6% for the arm curl). The reductions in 1RM loads correlated significantly to hand size and maximal isometric grip strength (r = -0.55 to -0.73). No differences were observed between bars for the bench press or shoulder press. In conclusion, the use of 2and 3-inch thick bars may result in initial weight reductions primarily for pulling exercises presumably due to greater reliance on maximal grip strength and larger hand size. KEY WORDS. grip strength, thick bars, deadlift, bent-over row, upright row

To achieve maximal force output, clinicians and coaches have been experimenting with upper extremity plyometric exercises for years, without sufficient scientific validation of this training method. The goal of this study was to examine the effects of an 8-week course of high volume upper extremity plyometric training on the isokinetic strength and throwing velocity of a group of intercollegiate baseball players. Twenty-four Division I collegiate baseball players (age: 19.7 [+ or -] 1.3 years; height: 183.9 [+ or -] 5.9 cm; mass: 90.7 [+ or -] 10.5 kg) were recruited to participate in this study. Throwing velocity, isokinetic peak torque, isokinetic functional strength ratios, and time to peak torque were measured pre- and posttraining. Subjects were rank-ordered according to concentric internal rotation (IR) strength and were assigned randomly to either the plyometric training group (PLY) or the control group (CON). Training consisted of 6 upper extremity plyometric exercises ('Ballistic Six') performed twice per week for 8 weeks. Subjects assigned to CON performed regular off-season strength and conditioning activities, but did not perform plyometric activities. PLY demonstrated significant increases (p < 0.05) in throwing velocity following 8 weeks of training when compared with CON (83.15 mph [pre] vs. 85.15 mph [post]). There were no statistically significant differences in any of the isokinetic strength measurements between PLY and CON groups pre- to posttraining. Statistically significant differences were seen within PLY for concentric IR and eccentric external rotation (ER) isokinetic strength at 180[degrees]*[s.sup.-1] and 300[degrees]*[s.sup.-1]; and within CON for eccentric ER isokinetic strength at 300[degrees]*[s.sup.-1] and concentric IR isokinetic strength at 180[degrees]*[s.sup.-1]. The Ballistic Six training protocol can be a beneficial supplement to a baseball athlete's off-season conditioning by improving functional performance and strengthening the rotator cuff musculature. KEY WORDS. muscle balance, power, rotator cuff, isokinetic, overhead-throwing

This study was designed to investigate the effect of mechanical vibration on acute power output in the bench press exercise. Ten male subjects who were experienced in resistance training participated in this study. Each subject performed 3 sets of 3 repetitions in the bench press exercise using a load equal to 70% of 1 repetition maximum in each of 2 sessions separated by 3 days. One session served as the experimental (vibration) condition, whereas the other session served as the control (no vibration) condition. The intervention (vibration or control) was applied between sets 2 and 3. The vibration was applied by a vibrating barbell apparatus held by the subjects while lying supine on a bench. The only difference between the 2 conditions was the vibration of the barbell apparatus during the vibration condition. Peak and average power were calculated during each bench press set to determine whether power output differed following vibration compared to control. Average power was significantly higher for the vibration condition compared to the control (525 [+ or -] 74 vs. 499 [+ or -] 71 W; p = 0.01). There was also a trend toward an increase in peak power in the vibration condition (846 [+ or -] 168 by vs. 799 [+ or -] 149 W; p = 0.06). In general, peak and average power output were higher following the vibration intervention compared to control. However, the sets prior to vibration application during the vibration condition also demonstrated higher power outputs compared with the control condition, which contributed to the main effect for the vibration condition. These results suggest that factors other than the vibration intervention influenced task performance during the vibration condition. We suggest that psychological factors related to the novelty of the vibration intervention were involved. These factors may partially explain the conflicting results of previous investigations that examined vibration as an exercise intervention. KEY WORDS. muscle strength, resistance training, facilitation

Changes in muscle mass and strength will vary, depending on the volume and frequency of training. The purpose of this study was to determine the effect of short-term equal-volume resistance training with different workout frequency on lean tissue mass and muscle strength. Twenty-nine untrained volunteers (27-58 years; 23 women, 6 men) were assigned randomly to 1 of 2 groups: group 1 (n = 15; 12 women, 3 men) trained 2 times per week and performed 3 sets of 10 repetitions to fatigue for 9 exercises, group 2 (n = 14; 11 women, 3 men) trained 3 times per week and performed 2 sets of 10 repetitions to fatigue for 9 exercises. Prior to and following training, whole-body lean tissue mass (dual energy x-ray absorptiometry) and strength (1 repetition maximum squat and bench press) were measured. Both groups increased lean tissue mass (2.2%), squat strength (28%), and bench press strength (22-30%) with training (p < 0.05), with no other differences. These results suggest that the volume of resistance training may be more important than frequency in developing muscle mass and strength in men and women initiating a resistance training program. KEY WORDS. periodization, intensity, recovery

The purpose of the present study was to examine differences in ratings of perceived exertion (RPE) and the weight lifted (training load) during self-selected and imposed-intensity bouts of acute resistance exercise (RE). Nineteen untrained college-aged women completed 2 bouts of acute resistance exercise. During 1 session, 3 sets of 4 exercises were performed using a training load of 75% of 1 repetition maximum. Conversely, during the other session, each set and exercise were completed using a self-selected training load. Assessments of RPE and training load were obtained following each set during both imposed-intensity and self-selected-intensity sessions. Results of 2 (intensity) x 3 (set) repeated measures multivariate analyses of variance revealed that, when compared to self-selected RE, RPE and resistance used were significantly higher and the number of repetitions completed per set was significantly lower during imposed-intensity RE. These findings demonstrate that the training load and perceptions of effort elicited during conventional RE prescriptions differ from the level of exertion untrained women self-select. Additionally, it appears that untrained women may not self-select a relative intensity sufficient to stimulate meaningful improvements in muscular hypertrophy or strength. The implications of these findings for the adoption and maintenance of resistance exercise participation are discussed. KEY WORDS. effort sense, preferred exertion, strength training, percentage of 1RM

Improvements in chemotherapy and radiotherapy have contributed to the high survival rate (~70%) of childhood acute lymphoblastic leukemia (ALL). However, during treatment, lack of physical activity and treatment cause various short- to long-term side effects, such as muscle atrophy and physical deconditioning. The purpose of this study was to determine the effects of an intrahospital, short-duration (8 weeks) exercise training program on muscle strength and endurance and functional mobility of children with ALL. Seven children (4 boys and 3 girls; 4-7 years of age) who were in the maintenance phase of treatment for ALL were selected as subjects. Three training sessions of 90- to 120minute duration were performed each week. Each session included 11 different strength exercises engaging the major muscle groups and aerobic training. Gains in strength and endurance were assessed with a 6 repetition maximum test for upper (seated bench press and seated lateral row) and lower extremities (leg press). Gains in functional mobility were assessed with the time up and go test (TUG) and the timed up and down stairs test (TUDS). Performance was significantly improved after the training program in all strength tests (p < 0.01 for seated bench press and p < 0.05 for both seated lateral row and seated leg press) and in the TUG test (p < 0.05). In summary, a period of time as short as 8 weeks is enough to produce clinically relevant early-phase adaptations in children receiving treatment against ALL (i.e., improved functional mobility and muscle strength). Although more research is needed in the area of exercise training and pediatric cancer, exercise sciences can play a beneficial role in assisting both oncologists in treating cancer and improving children's quality of life during and after treatment. KEY WORDS. resistance training, aerobic training, cancer

Despite the popularity of resistance training (RT), an accurate method for quantifying its metabolic cost has yet to be developed. We applied indirect calorimetry during bench press (BP) and parallel squat (PS) exercises for 5 consecutive minutes at several steady state intensities for 23 (BP) and 20 (PS) previously trained men. Tests were conducted in random order of intensity and separated by 5 minutes. Resultant steady state [Vo.sub.2] data, along with the independent variables load and distance lifted, were used in multiple regression to predict the energy cost of RT at higher loads. The prediction equation for BP was Y' = 0.132 + (0.031)([X.sub.1]) + (0.01)([X.sub.2), [R.sup.2] = 0.728 and [S.sub.xy] = 0.16; PS can be predicted by Y' = -1.424 + (0.022)([X.sub.1]) + (0.035)([X.sub.2]), [R.sup.2] = 0.656 and [S.sub.xy] = 0.314; where Y' is [Vo.sub.2], [X.sub.1] is the load measured in kg and [X.sub.2] is the distance in cm. Based on a respiratory exchange ratio (RER) of 1.0 and a caloric equivalent of 5.05 kcal*[L.sup.-1] , [Vo.sub.2] was converted to caloric expenditure (kcal*[min.sup.-1]). Using those equations to predict caloric cost, our resultant values were significantly larger than caloric costs of RT reported in previous investigations. Despite a potential limitation of our equations to maintain accuracy during very high-intensity RT, we propose that they currently represent the most accurate method for predicting the caloric cost of bench press and parallel squat. KEY WORDS. resistance training, weight lifting, oxygen cost, caloric cost

The purpose of this study was to examine the effect of low- vs. high-intensity resistance exercise on lipid peroxidation. In addition, the role of muscle oxygenation on plasma malondialdehyde (MDA) concentrations was explored. Eleven experienced resistance trained male athletes (age: 20.8 [+ or -] 1.3 years; weight: 96.2 [+ or -] 14.4 kg; height: 182.4 [+ or -] 7.3 cm) performed 4 sets of the squat exercise using either a low-intensity, high-volume (LI; 15 repetitions at 60% 1 repetition maximum [1RM]) or high-intensity, low-volume (HI; 4 repetitions at 90% 1RM load). Venous blood samples were obtained before the exercise (PRE), immediately following the exercise (IP), and 20 (20P) and 40 minutes (40P) postexercise. Continuous wave near-infrared spectroscopy was used to measure muscle deoxygenation in the vastus lateralis during exercise. Deoxygenated Hb/Mb change was used to determine reoxygenation rate during recovery. No difference in MDA concentrations was seen between LI and HI at any time. Significant correlations were observed between plasma MDA concentrations at IP and the half-time recovery ([T.sup.1/2] recovery) of muscle reoxygenation (r = 0.45) and between [T.sup.1/2] recovery and the area under the curve for MDA concentrations (r = 0.44). Results suggest that increases in MDA occur independently of exercise intensity, but tissue acidosis may have a larger influence on MDA formation. KEY WORDS. weight training, near-infrared spectroscopy, athletes, malondialdehyde, oxidative stress

The purpose of this study was to determine the effect resistance training has on metabolic economy during typical activities of daily living in a geriatric population. Twenty-nine men and women (age: 66.7 [+ or -] 4.4 years, body mass: 72.3 [+ or -] 11.9 kg) participated in a 26-week heavy-resistance training program. Before and after training, heart rate and expiratory gases were measured for subjects performing 3 tasks that would mimic common everyday activities encountered by this population: (a) walking (WLK) at 3 miles per hour (4.8 km*[h.sup.-1]), (b) carrying a box (CAR) to simulate holding a bag of groceries with 1 hand (30% of maximal isometric strength) while walking at 2 miles per hour (3.2 km*[h.sup.-1]), and (c) climbing stairs (STR). No time by gender interaction was observed for the WLK, CAR, and STR activities; consequently, the values for men and women were pooled. Both strength and fat-free mass increased significantly (p [less than or equal to] 0.001) after the training protocol, whereas body mass remained constant. Oxygen cost decreased significantly by 6% (p [less than or equal to] 0.05) only for CAR, whereas the respiratory exchange ratio decreased significantly (p [less than or equal to] 0.05) for both WLK (0.84-0.81) and STR (0.87-0.83), and heart rate decreased significantly (p [less than or equal to] 0.05) only for CAR. After the resistance training program, subjects also reported a significant decrease (p [less than or equal to] 0.05) in perceived exertion during performance of all functional task test conditions. These results suggest that a heavy-resistance training program might affect exercise economy during daily tasks and improve ease of physical activity, thereby providing a possible mechanism for increasing quality of life in an older and geriatric population. KEY WORDS. resistance exercise, elderly, physical activity

Although research has demonstrated that isokinetic eccentric (ECC) strength is 20-60% greater than isokinetic concentric (CON) strength, few data exist comparing these strength differences in standard dynamic resistance exercises. The purpose of the study was to determine the difference in maximal dynamic ECC and CON strength for 6 different resistance exercises in young men and women. Ten healthy young men (mean [+ or -] SE, 25.30 [+ or -] 1.34 years), and 10 healthy young women (mean [+ or -] SE, 23.40 [+ or -] 1.37 years) who were regular exercisers with resistance training experience participated in the study. Two sessions were performed to determine CON and ECC 1 repetitions maximum for latissimus pull-down (LTP), leg press (LP), bench press (BP), leg extension (LE), seated military press (MP), and leg curl (LC) exercises. Maximal ECC and maximal CON strength were determined on weight stack machines modified to isolate ECC and CON contractions using steel bars and pulleys such that only 1 type of contraction was performed. Within 2 weeks, participants returned and completed a retest trial in a counterbalanced fashioned. Test-retest reliability was excellent (r = 0.99) for all resistance exercise trials. Men demonstrated 20-60% greater ECC than CON strength (LTP = 32%, LP = 44%, BP = 40%, LE = 35%, MP = 49%, LC = 27%). Women's strength exceeded the proposed parameters for greater ECC strength in 4 exercises, p < 0.05 (LP = 66%, BP = 146%, MP = 161%, LC = 82%). The ECC/CON assessment could help coaches capitalize on muscle strength differences in young men and women during training to aid in program design and injury prevention and to enhance strength development. KEY WORDS. dynamic strength, gender

A decreased hamstring:quadriceps (H:Q) ratio may put the hamstrings and anterior cruciate ligament (ACL) at increased risk of injury. Therefore, the purpose of this study was to evaluate H:Q ratios of 12 female National Collegiate Athletic Association soccer players, and to test the effects of a 6-week strength training program on these ratios. Each subject completed 2 practice sessions before a pretest. Subjects then completed 6 weeks of strength training that included the addition of 2 hamstring specific exercises, followed by a posttest. Peak torque during concentric and eccentric actions for both hamstrings and quadriceps was measured with an isokinetic dynamometer. Each muscle action was tested at 3 angular velocities in the following order: concentric 240, 180, and 60[degrees]*[s.sup.-1] and eccentric 60, 180, and 240[degrees]*[s.sup.-1]. The H:Q strength ratio was evaluated using concentric muscle actions (concentric hamstrings: concentric quadriceps). This method is commonly used and is thus called the conventional ratio. Because concentric actions do not occur simultaneously in opposing muscles, a more functional assessment compares eccentric hamstring actions to concentric quadriceps actions. This functional ratio was also analyzed. Mean conventional and functional H:Q ratio data were analyzed using separate analysis of variance procedures with repeated measures on all factors (2 [Test] X 2 [Leg] X 3 [Angular Velocity]). The results revealed a significant main effect for factor (F test) with the functional ratio (p < 0.05) but not for the conventional ratio. The mean functional ratio increased from 0.96 [+ or -] 0.09 in pretest to 1.08 [+ or -] 0.11 in posttest. These results suggest that 6 weeks of strength training that emphasizes hamstrings is sufficient to significantly increase the functional ratio. The functional ratio after training exceeded 1.0, which is specifically recommended for prevention of ACL injuries. KEY WORDS. women, soccer, agonist, antagonist, injury prevention

The purpose of this study was to investigate the influence of different resistance exercise orders on the number of repetitions performed to failure and on the ratings of perceived exertion (RPE) in trained women. Twenty-three women with a minimum of 2 years of resistance training experience volunteered to participate in the study (age, 24.2 [+ or -] 4.5 years; weight, 56.9 [+ or -] 4.7 kg; height, 162.3 [+ or -] 5.9 cm; percent body fat, 18.2 [+ or -] 2.9%; body mass index, 22.2 [+ or -] 2 kg*[m.sup.-2]). Data were collected in 2 phases: (a) determination of a 1 repetition maximum (1RM) for the leg-press (LP), bench press (BP), leg extension (LE), seated machine shoulder press (SP), leg curl (LC), and seated machine triceps extension (TE); and (b) execution of 3 sets, with 2-minute rest intervals between sets and exercises, until fatigue using 80% of 1RM in 2 exercise sequences of the exact opposite order--Sequence A: BP, SP, TE, LP, LE, and LC, and Sequence B: LC, LE, LP, TE, SP, and BP. The RPE (Borg CR-10) was accessed immediately after each sequence and analyzed using a Wilcoxon test. A 2-way analysis of variance with repeated measurements, followed by a post hoc Fisher least significant difference test where indicated was used to analyze the number of repetitions per set of each exercise during the 2 sequences. The RPE was not significantly different between the sequences. The mean number of repetitions per set was always less when an exercise was performed later in the exercise sequence. The data indicate that in trained women, performance of both large- and small-muscle group exercises is affected by exercise sequence. KEY WORDS. strength training, performance, Borg scale, strength

Enhancing the acute quality of the resistance training stimulus is the goal of many research and applied professionals. To that end, many methods have been proposed and a variety of training strategies and ergogenic supplements have been investigated. Postactivation potentiation is one phenomenon that has been frequently examined, offering some promise in this regard. Though never previously applied in the strength and conditioning profession, dental research on jaw clenching, studies examining the Jendrassik maneuver and remote voluntary contractions and research on motor overflow together make a compelling case for the existence of a concurrent activation potentiation phenomenon and the acute ergogenic advantage associated with the simultaneous activation of muscles other than the prime mover or synergists. Evidence demonstrates that this advantage is accrued via activation of the H reflex and through cortical overflow. Ultimately, through research and practical application, athletes may be taught to optimize the type, timing, and magnitude of remote muscle actions in order to gain an ergogenic advantage and increase the acute response of the prime movers. This strategy may be especially useful during the most difficult portion of a resistance training repetition and during the most difficult repetitions of a resistance training set. KEY WORDS. Jendrassik maneuver, remote voluntary contractions, motor overflow, strength

The swiss is widely used in the recreational training environment as a supplement to conventional resistance training. One such application is to use the swiss ball as a bench support for bench press exercise. There is no evidence to indicate that the use of a swiss ball is beneficial for resistance training exercise. This study investigated muscle activity using surface electromyography of upper-body and abdominal muscles during the concentric and eccentric phases of the bench press on and off a swiss ball. Volunteers for this study were 14 resistance-trained subjects who performed isolated concentric and eccentric bench press repetitions using the 2 test surfaces with a 2-second cadence at a load equivalent to 60% maximum force output. The average root mean square of the muscle activity was calculated for each movement, and perceived exertion during the tasks was collected using a Borg Scale. The results of the study showed that deltoid and abdominal muscle activity was increased for repetitions performed using the swiss ball. Increased deltoid muscle activity supports previous findings for increased activity when greater instability is introduced to the bench press movement. Abdominal muscle activity increases were not hypothesized, but this finding provides scientific evidence for anecdotal reasoning behind swiss ball use as a potential core stability training device. KEY WORDS. electromyography, perceived exertion, unstable surface, resistance training

The purpose of this study was to compare the effect of 3 different rest intervals on the sustainability of squat and bench press repetitions over 5 consecutive sets performed with a 15 repetition maximum (RM)-load. Fifteen college-age men with previous resistance training experience were tested weekly over a period of 3 weeks. During each testing session, 5 consecutive sets of the squat and the bench press were performed with a 30-second, 1-minute, or 2-minute rest interval between sets. For each exercise, significant declines in repetitions occurred between the first and the fifth sets (p = 0.000). For the squat, a significant difference in the ability to sustain repetitions occurred between the 30-second and 2-minute rest condition Cp = 0.003). However, differences were not significant between the 30-second and l-minute rest conditions (p = 0.986) and between the l-minute and 2-minute rest conditions (p = 0.042). For the bench press, significant differences in the ability to sustain repetitions occurred between the 30-second and 2-minute rest conditions (p = 0.000) and between the 1-minute and 2-minute rest conditions (p = 0.000). However, differences were not significant between the 30-second and 1-minute rest conditions (p = 0.019). For each exercise, the number of repetitions completed on the first set was not sustained over subsequent sets, irrespective of the rest condition. These results suggest that when short rest intervals are used to develop muscular endurance, the intensity should be lowered over subsequent sets to sustain repetitions within the range conducive to this training goal. KEY WORDS. recovery, muscular endurance, fatigue, performance, volume

This study examined the construct validity of the Adult OMNI Perceived Exertion Scale for Resistance Exercise (OMNI-RES). Forty (20 men and 20 women) subjects performed 1 repetition of the knee extension exercise at 40, 50, 60, 70, 80, and 90% of the 1 repetition maximum. Active muscle and overall body ratings of perceived exertion (RPE) were collected from the Borg 15-category RPE scale and the OMNI-RES immediately following each repetition. Construct validity was established by correlating RPE from the OMNI-RES with RPE from the Borg RPE scale using regression analysis. The results indicated a positive and linear relationship between RPE from the OMNI-RES and RPE from the Borg scale for both men and women. Validity coefficients ranged from r = 0.94 to 0.97. The high level of construct validity indicates that the OMNI-RES measures the same properties of exertion as the Borg RPE scale during resistance exercise and suggests that the 2 scales can be used interchangeably during resistance exercise. KEY WORDS. RPE, gender, perceived exertion

Angiotensin II and endothelin-1 are potent vasoconstrictors that appear to play a role in retinal blood flow regulation. In the present study, we investigated the possible role of the angiotensin and the endothelin system in the regulation of retinal vessel diameters during isometric exercise in healthy humans. The study design was randomized, double-masked, placebo-controlled, and three-way cross over. Twelve healthy subjects performed squatting exercises for 6 min during infusion of either an angiotensin-converting enzyme inhibitor (enalapril), an E[T.sub.A]-receptor antagonist (BQ-123), or placebo. Retinal vessel diameters were measured continuously with the Zeiss retinal vessel analyzer. Systemic hemodynamics were assessed noninvasively, and intraocular pressure was measured with applanation tonometry. Squatting induced a significant increase in blood pressure and pulse rate, which was paralleled by a vasoconstriction in retinal arteries and veins. Intraocular pressure was only slightly increased during the squatting periods. BQ-123 significantly blunted the exercise-induced decrease in venous (P < 0.01) and arterial (P < 0.02, ANOVA) vessel diameters but had no effect on basal retinal diameters. By contrast, enalapril did neither influence vessel diameter at baseline conditions nor in response to isometric exercise. The data of the present study indicate that retinal vasoconstriction during isometric exercise is modified by ETA-receptor blockade, whereas it is not altered by angiotensin-converting enzyme inhibition. Hence, the present data indicate that endothelin-1, but not angiotensin II, is involved in retinal blood flow regulation during isometric exercise. retinal blood flow autoregulation; isometric exercise; human

We investigated the time-dependent modulation of arterial baroreflex (ABR) control of muscle sympathetic nerve activity (MSNA) that occurs during isometric handgrip exercise (1HG). Thirteen healthy subjects performed a 3-min IHG at 30% maximal voluntary contraction, which was followed by a period of imposed postexercise muscle ischemia (PEMI). The ABR control of MSNA (burst incidence and strength and total activity) was evaluated by analyzing the relationship between spontaneous variations in diastolic arterial pressure (DAP) and MSNA during supine rest, at each minute of IHG, and during PEMI. We found that 1) the linear relations between DAP and MSNA variables were shifted progressively rightward until the third minute of IHG (IHG3); 2) 2 min into IHG (IHG2), the DAP-MSNA relations were shifted upward and were shifted further upward at IHG3; 3) the sensitivity of the ABR control of total MSNA was increased at IHG2 and increased further at IHG3; and 4) during PEMI, the ABR operating pressure was slightly higher than at IHG2, and the sensitivity of the control of total MSNA was the same as at IHG2. During PEMI, the DAP-burst strength and DAP-total MSNA relations were shifted downward from the IHG3 level to the IHG2 level, whereas the DAP-burst incidence relation remained at the IHG3 level. These results indicate that during IHG, ABR control of MSNA is modulated in a time-dependent manner. We suggest that this modulation of ABR function is one of the mechanisms underlying the progressive increase in blood pressure and MSNA during the course of isometric exercise. arterial blood pressure; sympathetic nervous system; integrated circulatory regulation

Spreuwenberg, L.P.B., W.J. Kraemer, B.A. Spiering, J.S. Volek, D.L. Hatfield, R. Silvestre, J.L. Vingren, M.S. Fragala, K. Hfikkinen, R.U. Newton, C.M. Maresh, and S.J. Fleck. Influence of exercise order in a resistance-training exercise session. J. Strength Cond. Res. 20(1):141-144. 2006.--The order of resistance exercises within a training session may have a vital impact on the quality of the constituent exercises performed. However, very few studies have documented the specific influence of exercise order. Therefore, the purpose of this study was to examine the effect of exercise order on back squat performance in the context of a whole-body workout. Nine resistancetrained male subjects (age: 24 [+ or -] 4 years, body mass: 81.5 [+ or -] 15.3 kg, resistance-training experience: 7 [+ or -] 4 years) performed the back squat exercise (4 sets at 85% of 1 repetition maximum) on 2 separate occasions in a balanced, crossover design. During one protocol, the squat exercise was performed first (protocol A); during the other protocol, it was performed after a whole-body resistance-exercise session (protocol B). Number of repetitions, average power, and rating of perceived exertion (RPE) were collected during each set of the squat exercise. All subjects performed significantly (p < 0.01) more repetitions during set 1 when they performed protocol A (8.0 [+ or -] 1.9 repetitions) compared with protocol B (5.4 [+ or -] 2.7 repetitions). The average power for each set was higher during protocol B compared with protocol A. There were no significant differences in RPE values between the 2 protocols. In conclusion, performing the barbell back squat first in an exercise session allowed the completion of more total repetitions. However, this study showed that performing the squat exercise after a whole-body workout session may result in greater power output if the squat is preceded by a power exercise (i.e., hang pull). This phenomenon may have been due to postactivation potentiation. KEY WORDS. performance, postactivation potentiation, power output, resistance exercise, strength