Exercise sessions (swimming in rats and treadmill running in humans) resulted in stimulation of neutrophil degranulation in the experiments with animals and in the human study. Myeloperoxidase (MPO) (+67%) and lysozyme (+51%) quantities in the plasma of rats increased significantly immediately after exercise. The blood plasma lysozyme concentration was increased by 41% at the 6th min of treadmill exercise in athletes. The blood concentrations of neutrophil proteins normalized both in humans and animals at rest. The neutrophil protein concentrations in blood increased in parallel with the decrease of their level in leukocytes. The neutrophil capacity for an oxidative burst was not changed by the exercise, but decreased for 3-6 h in the post-exercise period. Such dynamics of the oxidative burst activity suggest a lack of association between this parameter and the degranulation process. The neutrophil proteins that appear in blood during degranulation can be involved in enhancing the bactericidal potency of blood, the activation of granulopoiesis, neutrophil efflux from bone marrow, and the conditioning of blood endothelium for leukocyte extravasation.

The primary purpose of this study was to examine the effects of high-intensity acute exercise on neutrophil infiltration in different muscle fiber types of untrained rats and to compare postexercise neutrophil accumulation in muscles of untrained and trained animals. The effect of high-intensity acute exercise on blood neutrophil degranulation reaction in trained animals was also elucidated. Neutrophil enzyme myeloperoxidase (MPO) was determined as a measure of neutrophil migration into muscles and blood neutrophil degranulation. Male albino rats were subjected to acute exercise and 5 weeks of training. The used model of intensive acute exercise consisted of 5, 15, and 25 intermittent swimming bouts with the addition of weight (8% of total body mass) for 1-min each, followed by 1.5-min rest intervals. MPO was analyzed in quadriceps muscle (white and red portion) and in soleus muscle 24 h after acute exercise. MPO content in resting blood plasma and neutrophils was determined 48-h following the completion of a training process. In addition, MPO content in the trained rats was measured immediately (in blood plasma and neutrophils) after and 24 h (in muscles) following a single-bout of exercise to exhaustion. The remaining two-third of the trained animals were exposed to a single-bout of nonstop swimming with the addition of 6% body mass until exhaustion. These animals were sacrificed immediately and 24 h after loaded swimming to analyze leukocyte count, MPO content in blood plasma and neutrophils and in muscles, respectively. About 24 h after exercise MPO concentrations in the red portion of quadriceps muscle and in soleus muscle were 4-7-fold higher as compared to the white portion of m. quadriceps. There was an association between the quantity of repetitive bouts of swimming and MPO content in the muscles. The duration of swimming to exhaustion of trained rats was 3.8-fold longer than untrained sedentary control. At rest, plasma MPO concentration was found to be 40% higher in trained rats compared to untrained controls (P < 0.05). Postexercise plasma MPO concentrations were significantly higher both in untrained (+137%; P < 0.05) and trained (+81%; P < 0.05) rats compared to resting values. At rest neutrophil MPO concentration was found to be 33% lower in trained rats compared to untrained controls (P < 0.05). There were no significant differences in muscle MPO concentrations between untrained and trained rats at rest. A single-bout of exercise to exhaustion produced a greater increase in MPO content in untrained compared to trained rats. The data suggest that postexercise neutrophil infiltration is more intensive in red fibers types compared to white fiber types. A smaller neutrophil infiltration in muscles of trained animals after exhaustive exercise suggests a protective effect of previous training to muscle injury.

The accuracy of regulating exercise intensity by Ratings of Perceived Exertion (RPE) was examined. Subjects underwent 4 production trials, 2 on a treadmill (P1A, P1B) and 2 on a cycle ergometer (P2A, P2B). 9 untrained subjects used only their perceptions of effort to regulate exercise intensity. Target intensity was the RPE equivalent to 60% VO2max. Exercise intensity (VO2) during P1A, P1B, and P2A did not differ from the target, but during P2B was lower than target. During P1A and P1B heart rate did not differ from the target but was lower than target during P2A and P2B. RPE seems a valid means of regulating exercise intensity during repeated bouts of treadmill exercise at 60% VO2max; however, exercise intensity during repeated bouts on the cycle ergometer may be lower than target.

The data suggest that 7 d of exercise is sufficient not only to improve insulin sensitivity and fat oxidation but also to favorably alter adipokine secretion, independent of changes in body weight or composition.

We assessed leisure-time Internet use (IU) and its relationship to physical fitness (PF) and leisure-time physical activity (PA) among 295 adolescent African-American girls. In addition, scales measuring variables in the Theory of Reasoned Action (TRA) were administered to elucidate PA data. Based on responses to the IU Questionnaire, participants were placed into either an Internet Nonuser (n = 184) or Internet User (n = 111) group. PF was assessed using body mass index (BMI) and AAHPERD Youth Fitness Tests. There were no correlations found between the fitness test scores and IU, PA, or BMI. No correlation was found between IU and PA, and similar findings were noted between PA and each variable constituting the TRA. As expected, within the TRA variables studied, significant moderate to high correlations were found between both Attitude to Exercise and Subjective Norm with Intention to Exercise, r = .43 and r = .53, respectively. The remarkably low scores among participants on the fitness tests and TRA scales suggest that IU would have no appreciable influence on the PF of this population, irrespective of IU.

No abstract

The purpose of the study was to acquire current anthropometric and physiological profiling of elite athletes and to examine differences in the characteristics. Methods: Three hundred and sixteen male, team-sport athletes were evaluated for anaerobic performance using the Wingate anaerobic test. Results: MANOVA procedures indicated significant differences in height among players of the sports. Pearson correlations indicated strong correlations for body mass with absolute peak power (Pp) and mean power (Pm), and relative Pm. Height correlated strongly with absolute Pp and Pm, with a low correlation with relative Pp. MANOVA procedures indicated that athletes who specialized in handball, volleyball, and basketball attained the greatest relative and absolute Pp, and the greatest relative Pm. Relative and absolute Pp of the soccer athletes were lowest of all other elite athletes. Conclusion: This study introduces normative values for elite male athletes, empowering coaches in the evaluation of anaerobic abilities and in the objective selection of athletes for competition.

Feelings of effort sense quantified via the Borg Rating of Perceived Exertion (RPE) scale have been validated for regulating exercise intensity. Most studies validating RPE for exercise prescription have used young, male subjects and only a few exercise sessions. As part of a larger study we examined the accuracy of RPE for regulating exercise intensity in a group of postmenopausal women. Six women (70.0+/-7.1 yr.) were given a maximal graded exercise test. Target RPEs equivalent to 40%, 50% and 60% VO2 max were developed from this test using standard techniques. These RPEs were used to regulate intensity during a 20-wk. training program. During the initial 5 wk. of training target intensity was increased from 40% to 60% VO2 max and exercise duration from 15 to 30 min. Accuracy of exercise intensity regulation was determined by comparing the heart rate during exercise to a target heart rate equivalent to the desired %VO2 max. At Week 2 of training (target 40% VO2 max) the mean intensity produced did not differ from target. During Weeks 4 (target 50% VO2 max), 6 and 10 of training (target 60% VO2 max) the mean exercise intensity was below target. At Week 20 the mean intensity produced was not different from target. This suggests that elderly women can accurately use RPE to regulate exercise intensity, but at intensities above 40% VO2 max an acclimation period is needed.