Barry S. Brown

Alterations in plasma-volume-corrected blood components of marathon runners and concomitant relationship to performance

SummaryThe study was undertaken to determine the effects of running a marathon on concentration of various blood components resulting from phenomena other than fluid loss, and these were related to performance times. Twenty male marathon runners ranging from 20 to 50 years of age participated in the study. Blood samples were collected before and after the subjects ran in a marathon. Blood samples were analyzed for sodium, potassium, glucose, lactate dehydrogenase, creatinine, creatine phosphokinase, triglycerides, cholesterol, hematocrit, hemoglobin, protein, white blood cell number, uric acid, carbon dioxide, and iron. All of the blood parameters increased significantly in concentration with the exceptions of glucose and carbon dioxide which decreased. After accounting for plasma-volume loss (COR), there remained significant increases in blood serum lactate dehydrogenase, creatinine, creatine phosphokinase, uric acid, iron, and whole-blood white blood cell number. Significant decreases in COR serum sodium, protein, glucose, and carbon dioxide were found. Lactate dehydrogenase and creatine phosphokinase concentration changes support the concept of acute damage to muscle tissue resulting from marathon running. No strong relationship between performance time and other measured variables was found. COR measures were more representative of marathon induced blood changes from physiological dynamics other than plasma volume change than presently reported findings.

Predicting Performance on a Firefighter's Ability Test From Fitness Parameters

The purpose of this project was to identify the relationships between various fitness parameters such as upper body muscular endurance, upper and lower body strength, flexibility, body composition and performance on an ability test (AT) that included simulated firefighting tasks. A second intent was to create a regression model that would predict firefighter performance on the test. Thirty-eight experienced firefighters performed the AT and underwent assessments for the fitness parameters. Multiple regression analyses indicated that variation in the fitness parameters explained a significant, F(6, 36) = 6.31, p < .001, proportion (55%) of the variation observed in the AT. The results demonstrated that upper muscular strength and endurance as well as low body composition were significantly related (p < .01) to better performances on the simulated firefighting tasks. Variables such as low back and hamstring flexibility, upper and lower body strength, and body composition may contribute significantly to the models predictive power.

Influence of Yard Work and Weight Training on Bone Mineral Density Among Older U. S. Women

ABSTRACT The purpose of this study was to determine the influence of type of physical activity on bone mineral density among older U.S. women. Findings from the present study indicate that jogging, swimming and calisthenics were weak predictors for high bone density values. Bicycling, aerobics, walking and dancing were moderate predictors for positive bone density. Yard work and weight training were strong and independent predictors for positive bone density.

Variables for the prediction of femoral bone mineral status in American women.

Introduction: A reliable procedure for identifying persons at risk for osteoporosis and subsequent fracture is needed so that preventive measures may be initiated. Material and Methods: Participants included 7,532 women, ages 20 and older, surveyed in the National Health and Nutrition Examination Survey III (NHANES, 1988–1994). Influences of race, body composition, exercise, alcohol intake, smoking status, as well as the effect of nutritional intake of calcium, phosphorus, magnesium, iron, zinc, sodium, and potassium on bone mineral density (BMD) were assessed. Results: Advancing age, low body weight, low exercise expenditure, and smoking were significant predictors for low BMD. Nutritional variables examined were not significant in the predictive models. Conclusions: The absence of calcium from the predictive models indicates the need for re-evaluation of the current recommended intake levels of this nutrient. A greater emphasis on factors such as exercise and achieving adequate weight is recommended. Discussion: Providing women with the knowledge of their risk for low BMD may influence lifestyle behaviors, which may ultimately result in the prevention of bone injury.

Physiological and Hematological Changes among Basketball Players during Preseason

Abstract Past studies of male basketball players have been limited to skill analyses, anthropometric measures, strength determination, predictive motor ability tests, and two studies conducted on heart rate and blood pressure following preseason training. The present study has attempted to assess maximal aerobic capacity, hematological determinations as well as selected anthropometric and strength measures among the entire University of Arkansas basketball team. Measures were taken at the beginning and conclusion of an 8-wk preseason training program, which combined interval and distance running with a 3 day/wk weight lifting regimen. Significant changes were found in body weight (2 lb), upper arm girth (.15 in.), skinfolds (triceps: −.8 mm; thigh: −1.2 mm; iliac crest: −1.3 mm; subscapulae: −.4 mm and percentage body fat: −.9%), horizontal flexion (dominant: 25.0 lb; nondominant: 25.9 lb), elbow extension (nondominant: 14.8 lb), leg strength (121.9 lb), recovery heart rate (at 2 min: −8.3), diastolic blo...

STRENGTH AND ANTHROPOMETRIC CHARACTERISTICS OF SELECTED OFFENSIVE AND DEFENSIVE UNIVERSITY-LEVEL FOOTBALL PLAYERS

Prediction of football-playing ability from several tests of power and anthropometric measures and a prediction of body fat from several skinfold sites was determined among university-level football players. Success in football ability, determined from the coachs rating, correlated highly with skinfolds, % body fat, and a few power measures. Skinfold estimates of body fat can be accurately assessed (r = .92) from two sites, iliac crest and cheek. Football teams would benefit from periodic “in-season” and “offseason” checks on body fat to ensure compliance to a year-long training program.