Although it is generally accepted that human performance must be assessed in a manner specific to the training, previous studies have violated this principle. In order to determine the validity of evaluating short-term resistance training programs with isometric and isokinetic measures, 23 recreationally active males participated in an 8-week training program. Subjects were randomly divided into barbell squat, hip sled, leg extension, and control groups. Pre- and posttesting of quadriceps strength was performed with a Cybex isokinetic dynamometer. Six angle-specific torques (N.m) were determined at 0 rad-s-1 and 1.05 rad-s-1. Ten RM training loads increased significantly for all groups that trained. Isometric torque values differed significantly from isokinetic torque values at 30, 60, 75, and 90° of leg flexion for all groups. No significant torque increases from pre- to posttest were observed for any group at any limb angle for either isometric or isokinetic testing, or for isokinetic peak torque. This indicates that strength increases during short-term dynamic external resistance exercise are not adequately assessed with either isometric or isokinetic evaluations.
Andrew C. Fry, Dawn R. Powell and William J. Kraemer
Eric L. Gossick and Andrew C. Fry
Candace M. Hogue, Mary D. Fry, Andrew C. Fry and Sarah D. Pressman
Research in achievement goal perspective theory suggests that the creation of a caring/task-involving (C/TI) climate results in more advantageous psychological and behavioral responses relative to an ego-involving (EI) climate; however, research has not yet examined the physiological consequences associated with psychological stress in relation to climate. Given the possible health and fitness implications of certain physiological stress responses, it is critical to understand this association. Thus, the purpose of this study was to examine whether an EI climate procures increases in the stress-responsive hormone cortisol, as well as negative psychological changes, following the learning of a new skill, compared with a C/TI climate. Participants (n = 107) were randomized to a C/TI or an EI climate in which they learned how to juggle for 30 min over the course of 2 hr. Seven salivary cortisol samples were collected during this period. Results indicated that EI participants experienced greater cortisol responses after the juggling session and significantly greater anxiety, stress, shame, and self-consciousness relative to C/TI participants. In contrast, the C/TI participants reported greater enjoyment, effort, self-confidence, and interest and excitement regarding future juggling than the EI participants. These findings indicate that motivational climates may have a significant impact on both the physiological and psychological responses of participants.
Andrew C. Fry, Carol C. Irwin, Justin X. Nicoll and David E. Ferebee
To determine absolute and relative (adjusted for body mass) strength, mean power, and mean velocity for upper and lower body resistance exercises, forty-seven young boys and girls participated in maximal strength testing. Healthy young boys and girls, ages 3- to 7-years old, were tested for one-repetition maximum (1-RM) strength, and 70% of 1-RM to determine mean power and mean velocity on the chest press and leg press exercises. Adult weight machines were modified to accommodate the smaller size and lower strength levels of the children. A 2 × 4 (sex × age) ANOVA was used to determine age and sex differences in performance. No interaction or sex differences were observed for any variable at any age. 1-RM strength, mean power, and mean velocity significantly increased across ages (p ≤ .05). When adjusted for body mass, the changes were insignificant, with one exception. Relative mean power for the bench press increased with age. Data indicated children from 3-7 years of age are capable of performing strength and power tests, but may require more attempts at maximal loads compared with adults. It appears that muscular strength and velocity during this stage of development are primarily dependent on increasing body mass, whereas power is influenced by additional variable(s).
Webb A. Smith, Andrew C. Fry, Lesley C. Tschume and Richard J. Bloomer
The purpose of this study was to evaluate the effect of glycine propionyl-Lcarnitine (GPLC) supplementation and endurance training for 8 wk on aerobicand anaerobic-exercise performance in healthy men and women (age 18–44 yr). Participants were randomly assigned to 1 of 3 groups: placebo (n = 9), 1 g/d GPLC (n = 11), or 3 g/d GPLC (n = 12), in a double-blind fashion. Muscle carnitine (vastus lateralis), VO2peak, exercise time to fatigue, anaerobic threshold, anaerobic power, and total work were measured at baseline and after an 8-wk aerobic-training program. There were no statistical differences (p > .05) between or within the 3 groups for any performance-related variable or muscle carnitine concentrations after 8 wk of supplementation and training. These results suggest that up to 3 g/d GPLC for 8 wk in conjunction with aerobic-exercise training is ineffective for increasing muscle carnitine content and has no significant effects on aerobic- or anaerobic-exercise performance.
Andrew C. Fry, William J. Kraemer, James M. Lynch and Jason M. Barnes
To report a joint-centered mechanism of performance decrements caused by overtraining.
Eleven weight-trained men, 1 (subject A) with overload injury of the knees.
High-intensity squat resistance-exercise overtraining for 2 weeks.
1RM lower-body strength, isokinetic and isometric knee-extension strength, and stimulated isometric knee-extension strength.
Subject A’s 1RM strength decreased 40.3 kg, and the other overtrained subjects (OT) exhibited significant (P < .05) 1RM decrements (x = –9.3 kg). Isokinetic knee-extension strength decreased for all subjects. For the OT group, voluntary isometric knee-extension strength did not change and stimulated isometric knee-extension strength decreased. Subject A exhibited increased values for both these variables.
These data indicate that muscle strength was attenuated for subject A only during dynamic activity. It is theorized that subject A exhibited a joint-centered overtraining syndrome, with afferent inhibition from the affected joints impairing dynamic strength.
William J. Kraemer, Andrew C. Fry, Peter N. Frykman, Brian Conroy and Jay Hoffman
The use of resistance training for children has increased in popularity and interest. It appears that children are capable of voluntary strength gains. Exercise prescription in younger populations is critical and requires certain program variables to be altered from adult perspectives. Individualization is vital, as the rate of physiological maturation has an impact on the adaptations that occur. The major difference in programs for children is the use of lighter loads (i.e., > 6 RM loads). It appears that longer duration programs (i.e., 10-20 wks) are better for observing training adaptations. This may be due to the fact that it takes more exercise to stimulate adaptational mechanisms related to strength performance beyond that of normal growth rates. The risk of injury appears low during participation in a resistance training program, and this risk is minimized with proper supervision and instruction. Furthermore, with the incidence of injury in youth sports, participation in a resistance training program may provide a protective advantage in one’s preparation for sports participation.
Loren Z.F. Chiu, Brian K. Schilling, Andrew C. Fry and Lawrence W. Weiss
Displacement-based measurement systems are becoming increasingly popular for assessment of force expression variables during resistance exercise. Typically a linear position transducer (LPT) is attached to the barbell to measure displacement and a double differentiation technique is used to determine acceleration. Force is calculated as the product of mass and acceleration. Despite the apparent utility of these devices, validity data are scarce. To determine whether LPT can accurately estimate vertical ground reaction forces, two men and four women with moderate to extensive resistance training experience performed concentric-only (CJS) and rebound (RJS) jump squats, two sessions of each type in random order. CJS or RJS were performed with 30%, 50%, and 70% one-repetition maximum parallel back squat 5 minutes following a warm-up and again after a 10-min rest. Displacement was measured via LPT and acceleration was calculated using the finite-difference technique. Force was estimated from the weight of the lifter-barbell system and propulsion force from the lifter-barbell system. Vertical ground reaction force was directly measured with a single-component force platform. Two-way random average-measure intraclass correlations (ICC) were used to assess the reliability of obtained measures and compare the measurements obtained via each method. High reliability (ICC > 0.70) was found for all CJS variables across the load-spectrum. RJS variables also had high ICC except for time parameters for early force production. All variables were significantly (p < 0.01) related between LPT and force platform methods with no indication of systematic bias. The LPT appears to be a valid method of assessing force under these experimental conditions.
Andrew C. Fry, William J. Kraemer, Michael H. Stone, Beverly J. Warren, Jay T. Kearney, Carl M. Maresh, Cheryl A. Weseman and Steven J. Fleck
To examine the effects of 1 week of high volume weightlifting and amino acid supplementation, 28 elite junior male weightlifting received either amino acid (protein) or lactose (placebo) capsules using double-blind procedures. weightlifting test sessions were performed before and after 7 days of high volume training sessions. Serum concentrations of testosterone (Tes), cortisol (Cort), and growth hormone (GH) as well as whole blood iactate (HLa) were determined from blood draws. Lifting performance was not altered for either group after training, although vertical jump performance decreased for both groups. Both tests elicited significantly elevated exercise-induced hormonal and HLa concentrations. Significant decreases in postexercise hormonal and HLa concentrations from Test 1 to Test 2 were observed for both groups. Tes concentrations at 7 a.m. and preexercise decreased for both groups from Test 1 to Test 2, while the placebo group exhibited a decreased 7 a.m. Tes/ Cort. These data suggest that amino acid supplementation does not influence resting or exercise-induced hormonal responses to 1 week of high volume weight training, but endocrine responses did suggest an impending overtraining syndrome.
William J. Kraemer, N. Travis Triplett, Andrew C. Fry, L. Perry koziris, Jeffrey E. Bauer, James M. Lynch, Tim McConnell, Robert U. Newton, Scott E. Gordon, Richard C. Nelson and Howard G. Knuttgen
The purpose of this study was to provide an in-depth sports medicine profile of women college tennis players and determine the relationships among an array of performance and clinical variables. Thirty-eight non-resistance-trained women from NCAA Divisions I and III collegiate tennis teams participated. A comprehensive battery of performance tests was conducted on each subject, including measurements of dynamic, isometric, and isokinetic strength; joint laxity and flexibility; speed; agility; power and power endurance; peak oxygen consumption; body composition; and ball velocities of the serve, forehand, and backhand. It was found that no single variable strongly explains tennis performance. The low amount of shared variance of strength measures with ball velocities suggests that tennis skills play a large role in producing peak ball velocities in this group. Due to the large range observed in profiled variables, individual evaluation is needed for clinical and conditioning recommendations.