The purpose of this study was to determine the effect of long-term Cr supplementation on blood parameters reflecting liver and kidney function. Twenty-three members of an NCAA Division II American football team (ages = 19–24 years) with at least 2 years of strength training experience were divided into a Cr monohydrate group (CrM, n = 10) in which they voluntarily and spontaneously ingested creatine, and a control group (n = 13) in which they took no supplements. Individuals in the CrM group averaged regular daily consumption of 5 to 20 g (mean ± SD = 13.9 ± 5.8 g) for 0.25 to 5.6 years (2.9 ± 1.8 years). Venous blood analysis for serum albumin, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, bilirubin, urea, and creatinine produced no significant differences between groups. Creatinine clearance was estimated from serum creatinine and was not significantly different between groups. Within the CrM group, correlations between all blood parameters and either daily dosage or duration of supplementation were nonsignificant. Therefore, it appears that oral supplementation with CrM has no long-term detrimental effects on kidney or liver functions in highly trained college athletes in the absence of other nutritional supplements.
David L. Mayhew, Jerry L. Mayhew and John S. Ware
Jerry L. Mayhew, Michael G. Bemben and Donna M. Rohrs
The purpose of this study was to determine the relationships among the seated shot put (SSP), bench press power (BPP), and body composition in adolescent wrestlers. Seventy-five wrestlers from three high schools were tested during their preseason training. Upper body power was tested with a plate-loaded bench press machine equipped with infrared sensors attached to a digital timer. Each subject was given three trials with a constant 24.5-kg load (CLP) and with a variable load equal to 60% of body mass (VLP). Skinfolds were used to estimate body composition. The SSP was significantly related to both CLP and VLP as well as to body mass, lean body mass (LBM), and % fat. Removing the effect of body mass reduced the relationship between SSP and both CLP and VLP. Removing the effect of LBM had a slightly greater effect on the relationships between SSP and both CLP and VLP, although the correlations remained significant. Therefore it appears that the SSP is only moderately related to upper body power in adolescent wrestlers and may be greatly influenced by size and muscularity.
Lori M. Cox, Christopher D. Lantz and Jerry L. Mayhew
Early identification of potentially harmful eating patterns is critical in the effective remediation of such behaviors. The purpose of this investigation was to examine the degree lo which various factors including gender, family history, and athletic status predict disordered eating behavior; social physique anxiety and percent body fat were added as potential predictor variables. The eating behaviors of student-athletes and nonathlete students were also compared. One hundred eighty undergraduate students (males = 49, females =131) provided demographic information and completed the Eating Attitudes Test (EAT) and the Social Physique Anxiety Scale (SPAS). Stepwise multiple-regression analysis indicated that social physique anxiety, gender, and body fat (%Fat) combined to predict 34% of disordered eating behaviors: EAT = 0.921 SPA - 1.05 %Fat + 10.95 Gender (1 = M. 2 = F) - 17.82 (R 2 = .34, SE = 4.68). A one-way ANOVA comparing ihe eating behaviors of athletes and nonathletes revealed no significant difference between these groups.
Jeffrey A. Borgmeyer, Bradley A. Scott and Jerry L. Mayhew
The effect of ice massage on muscle-strength performance is equivocal.
To determine the effects of ice massage on maximum isokinetic torque produced during a 20-minute interval.
Participants performed a maximal isokinetic contraction of the right arm at 30°/s every 2 minutes for 20 minutes, once after a 10-minute ice massage over the right biceps brachii muscle belly and once without ice treatment. Sessions were randomized.
11 college men.
Torque was measured with a Cybex® II dynamometer. Biceps skinfold was measured with a Harpenden caliper.
A repeated-measures ANCOVA revealed no significant interaction between time and treatment condition when the effect of skinfold thickness was held constant. A main effect for time indicated that torque production was significantly higher at 4 and 8 minutes and declined thereafter.
A 10-minute ice massage neither enhanced nor retarded muscle-force output and thus may be used for its pain-reducing effect to allow resistance exercise during the rehabilitation process
Jerry L. Mayhew, Tom P. McCormick, Fontaine C. Piper, Amy L. Kurth and Michael D. Arnold
The purpose of this study was to determine the degree to which structural dimensions are related to strength performance in novice adolescent powerlifters. Ninety-nine high school males were measured for 17 anthropometric dimensions and maximal performance in the bench press and deadlift. Body mass and limb circumferences had the highest relationships with lifting performance. Removing the effect of body mass dramatically reduced the relationships between structural dimensions and lift performances. Multiple regression analysis indicated that size and structural dimensions could account for 68.9% and 62.4% of the known variance in the bench press and deadlift, respectively. Body size was the major determinant of weightlifting ability in adolescent male athletes, with structural dimensions playing a lesser role in determining success.
Jerry L. Mayhew, Michael G. Bemben, Donna M. Rohrs, Fontaine C. Piper and Michael K. Willman
The purpose of this study was to compare the measurement of upper body power between male (n = 36) and female (n = 23) adolescent wrestlers and basketball players using the seated shot put (SSP) and a bench press power test (BPP). Boys were significantly different from girls on all physical and performance measures except age. The two SSP tests were significantly related to the two BPP tests in boys, but not in girls. Both SSP tests were significantly related to body mass and fat-free mass (FFM) in boys, but not in girls. Removing the effect of body mass or FFM reduced the relationships of both SSP tests with both BPP tests. BPP output was more dependent on age, height, and body mass in boys than in girls. The SSP may be measuring a different component of upper body power than a BPP test in either male or female adolescent athletes.
Jerry L. Mayhew, Sidney Palmer Hill, Melissa D. Thompson, Erin C. Johnson and Lyndsay Wheeler
The purpose of this study was to evaluate the effectiveness of repetitions to fatigue (RTF) using absolute and relative muscle-endurance performances to estimate 1-repetition-maximum (1-RM) bench-press performance in high school male athletes.
Members of high school athletic teams (n = 118, age = 16.5 ± 1.1 y, weight = 82.7 ± 18.7 kg) were tested for 1-RM bench press and RTF with an absolute load of 61.4 kg and a relative load that produced 7 to 10 RTF (7- to 10-RM). All participants had completed a minimum of 4 wk of resistance training before measurement.
All 7- to 10-RM-prediction equations had higher correlations between predicted and actual 1-RM (r > .98) than the 61.4-kg absolute-load equation (r = .95). Despite the high correlations, only 3 of 11 equations produced predicted values that were nonsignificantly different from actual 1-RM. The best 7- to 10-RM equation predicted 65% of the athletes’ performances within ±4.5 kg of their actual 1-RM. The addition of simple anthropometric dimensions did not increase the validity correlations or decrease the prediction errors.
The 7- to 10-RM method can provide an accurate method of estimating strength levels for adjusting loads in a training program and is more accurate for predicting 1-RM bench press in high school athletes than the 61.4-kg repetition method.