Edward P. Hebert

College Students' Motivation for Physical Activity: Differentiating Men's and Women's Motives for Sport Participation and Exercise

Despite the many clear benefits of an active lifestyle, lack of physical activity is a significant health problem in the college population. A key issue in physical activity research is developing an understanding of motivation. Although physical activity takes many forms, most research designed to enhance motivation for and adherence to physical activity focuses on exercise behavior and ignores sport participation. In this study, the authors compare motivations for sport participation versus exercise among college students. Results indicate that participants were more likely to report intrinsic motives, such as enjoyment and challenge, for engaging in sport, whereas motivations for exercise were more extrinsic and focused on appearance and weight and stress management. The findings suggest that motives for sport participation are more desirable than those for exercise and may facilitate improved adherence to physical activity recommendations.

Does the First Year of Teaching Have To Be a Bad One? A Case Study of Success.

Abstract During the past two decades, researchers have shown considerable interest in teachers engaged in their first year of employment, a career phase believed to have long-term implications for teaching effectiveness, job satisfaction, and career length. One result of this line of inquiry is an extensive set of case studies describing failure in first-year teaching. However, there are occasional reports of positive examples of teacher induction, and close examination of new teachers who succeed has been suggested as an alternative means to understand success and failure in teaching. The study reported here is a case study of success in first-year teaching. Based on observations and interviews conducted over the course of one academic year, it focuses on the descriptions and interpretations of a new physical education teacher at a public school in the United States. The results revealed several factors which impacted the success of the first-year teacher studied, some related to preservice teacher preparation, others to school context, and others a result of taking an active role in the school social context. Three major themes evolved: (a) a match between expectations, personality, and workplace realities; (b) evidence of impact; and (c) using successful strategies to manage student behavior and enter the social and political culture of the school. The findings draw attention to the interplay between personal background, experiences during teacher preparation, and workplace characteristics as influences of not only relative success in teaching, but also a teachers perceptions and interpretations of her school, students, and teaching performance.

Rigorous Running Increases Growth Hormone and Insulin-Like Growth Factor-I Without Altering Ghrelin

It has been suggested that ghrelin may play a role in growth hormone (GH) responses to exercise. The present study was designed to determine whether ghrelin, GH, insulin-like growth factor-I (IGF-I), and IGF-binding protein-3 (IGFBP-3) were altered by a progressively intense running protocol. Six well-trained male volunteers completed a progressively intense intermittent exercise trial on a treadmill that included four exercise intensities: 60%, 75%, 90%, and 100% of Vo2max. Blood samples were collected before exercise, after each exercise intensity, and at 15 and 30 mins following the exercise protocol. Subjects also completed a separate control trial at the same time of day that excluded exercise. GH changed significantly over time, and GH area under the curve (AUC) was significantly higher in the exercise trial than the control trial. Area under the curve IGF-I levels for the exercise trial were significantly higher than the control trial. There was no difference in the ghrelin and IGFBP-3 responses to the exercise and control trials. Pearson correlation coefficients revealed significant relationships between ghrelin and both IGF-I and IGFBP-3; however, no relationship between ghrelin and GH was found. In conclusion, intense running produces increases in total IGF-I concentrations, which differs from findings in previous studies using less rigorous running protocols and less frequent blood sampling regimens. Moreover, running exercise that produces substantial increases in GH does not affect peripheral ghrelin levels; however, significant relationships between ghrelin and both IGF-I and IGFBP-3 exist during intense intermittent running and recovery, which warrants further investigation.

The influence of self-talk on the performance of skilled female tennis players

Abstract This paper reports on the development and implementation of a self-talk (ST) strategy designed to improve the volleying skill of collegiate tennis players (N = 5). A two-word ST strategy was developed, implemented, and evaluated using a single-case, multiple-baseline design. Dependent measures were movement patterns and outcome scores. After intervention, four players displayed immediate, positive changes with no overlapping datapoints on movement patterns. Notable improvements in outcome scores were also observed in all players, however, overlapping datapoints occurred for three players. Visual inspection of plotted values was supplemented by quantitative analysis using one-way ANOVAs to analyze four datapoints: the two baseline days just prior to intervention, and the two days immediately post intervention. Significant differences were found between phases, with both movement pattern and outcome scores higher following intervention. Qualitative data were collected via surveys and interviews. Pl...

Adiponectin responses to continuous and progressively intense intermittent exercise.

PURPOSE Adiponectin is a recently discovered adipocyte protein that is lower in patients with coronary artery disease and in Type II diabetics who have insulin resistance. Regular exercise is known to be a preventative factor in the development of atherosclerosis and Type II diabetes. Acute exercise increases insulin sensitivity; however, it also increases beta-adrenergic and glucocorticoid activities that may suppress adiponectin expression. Two experiments were conducted to determine whether acute exercise affects adiponectin concentrations. METHODS In the first experiment, six healthy male subjects completed 30 min of heavy continuous running exercise at 79% of VO (2max). In the second experiment, well-trained runners completed strenuous intermittent exercise consisting of treadmill running at 60, 75, 90, and 100% VO (2max). A resting control trial for the second experiment was also conducted. RESULTS Glucose and insulin were not altered significantly in the first experiment, but both increased significantly (P < 0.05) in the second experiment. A significant increase (P < 0.05) in adiponectin in the first experiment was no longer significant after correction for plasma volumes shifts. In the second experiment, there were significant (P < 0.05) changes in adiponectin concentrations over time but not a significant difference between adiponectin responses in exercise and control trials. CONCLUSIONS The data suggest that 30 min of heavy continuous running or more strenuous intermittent running does not stimulate an increase in production and release of adiponectin, and small increases in adiponectin concentrations resulting from the exercise may be attributed to normal plasma volume shifts.

Practice Schedule Effects on the Performance and Learning of Low- and High-Skilled Students: An Applied Study

This study examined the effects of practice schedule manipulations implemented in an instructional setting on the performance and learning of low- and high-skilled students. College undergraduates (N = 83) enrolled in 5 tennis classes completed a pretest on the forehand and backhand ground strokes, practiced these skills under a blocked or alternating schedule, and then completed a posttest. Results indicated that practice schedule effects on learning were influenced by student ability. Low-skilled students assigned to the blocked schedule had higher posttest scores than those assigned to the alternating schedule, whereas no significant differences were found for high-skilled students. These findings are discussed in relation to previous applied and laboratory-based findings and as a means for manipulating practice difficulty in teaching physical education.

Circuit weight training and its effects on excess postexercise oxygen consumption.

OBJECTIVE There is a paucity of research concerning energy expenditure during and after circuit weight training (CWT). There is evidence that duration of rest between sets affects metabolic responses to resistive exercise. The purpose of the study was to determine the effect of rest-interval duration upon the magnitude of 1 h of excess postexercise oxygen consumption (EPOC). METHODS Seven healthy men completed two randomized circuit weight training sessions using 20-s and 60-s rest intervals (20 RI, 60 RI). Sessions included two circuits of eight upper and lower body resistive exercises in which 20 repetitions were performed at 75% of a previously determined 20 repetition maximum. RESULTS The 1 h EPOC of 10.3 +/- 0.57 L for the 20 RI session was significantly higher than 7.40 +/- 0.39 L for the 60 RI session. The net caloric expenditure during 1 h of recovery from the 20 RI session was significantly higher than that of the 60 RI session (51.51 +/- 2.84 vs 37.00 +/- 1.97 kcal); however, total gross energy expenditure (exercise + 1 h recovery) was significantly greater for the 60 RI protocol (277.23 kcal) than the 20 RI protocol (242.21 kcal). CONCLUSION Data demonstrate that shortening the rest interval duration will increase the magnitude of 1 h EPOC from CWT; however, the exercise + recovery caloric costs from CWT are slightly greater for a longer rest interval duration protocol. These data suggest that total caloric cost be taken into account for CWT.

Hormonal responses from concentric and eccentric muscle contractions

UNLABELLED Intense resistance exercise can acutely increase testosterone (T), free testosterone (FT), and growth hormone (GH) concentrations, but there are few investigations concerning acute endocrine responses to concentric (CON) and eccentric (ECC) contractile actions. PURPOSE The purpose of the study was to compare acute anabolic hormonal responses to bouts of dynamic CON and ECC contractions from multiple exercises at the same absolute load. METHODS Ten young men (age: 24.7 +/- 1.2 yr, weight: 85.45 +/- 24.2 kg, and height: 178 +/- 0.2 cm) completed two trials in counterbalanced fashion consisting of only CON or ECC contractions at the same absolute workload. Subjects performed four sets of 12 repetitions of bench press, leg extension, military press, and leg curl at 80% of a 10-repetition maximum with 90-s rest periods. Blood samples were collected pre-, post-, and 15-min postexercise. RESULTS There were significant increases in GH, T, and FT and lactate for both trials, but only GH and lactate were greater for the CON trial. CONCLUSION CON exercise increases GH concentrations to a much greater extent than ECC exercise at the same absolute load, and it is likely that greater GH responses were related to intensity rather than mode of contraction. Also, CON and ECC dynamic contraction trials at the same absolute workload elicited similar small but significant increases in T and FT, indicating that the greater metabolic stress produced by during the CON trial did not affect these hormone responses.

Ghrelin and Other Glucoregulatory Hormone Responses to Eccentric and Concentric Muscle Contractions

Objective: Heavy resistance exercise increases growth hormone (GH) and blood glucose levels. Ghrelin is an endogenous ligand for the GH secretagory receptor that stimulates growth hormone release. Circulating ghrelin levels are suppressed by insulin and glucose. The study was conducted to determine effects of concentric (CON) and eccentric (ECC) muscle actions at the same absolute workload on circulating ghrelin and glucose as well as related glucoregulatory peptides.Methods: Ten-RM loads for bench press, leg extension, military press, and leg curl were obtained from nine males, mean age 25.±1.2 yr and body fat 17.2±1.6%. Subjects then completed two experimental trials of either CON or ECC contractions at the same absolute workload. Subjects performed four sets of 12 repetitions for each exercise at 80% of a 10-RM with 90 s rest periods. A pulley system or steel levers were positioned on each machine to raise or lower the weight so only CON or ECC contractions were performed. Pre-, post-, and 15-min post-exercise blood samples were collected.Results: Ghrelin did not increase in response to either muscle action and actually declined during the CON trial. Glucose and insulin increased regardless of the form of muscle action, but amylin and C-peptide did not change.Conclusions: Data indicate that ghrelin does not contribute to moderate resistance exercise-induced increases in growth hormone, whether from CON or ECC muscle actions. Results suggest that with a moderate loading protocol both CON and ECC muscle actions performed at the same absolute workload elevate glucose and insulin concentrations, but are not related to post-CON exercise ghrelin suppression.

A Comparison of Three Practice Schedules along the Contextual Interference Continuum

T he organization of practice sessions is recognized as one of the most important functions teachers and coaches perform (Silverman, 1990; Vickers, 1990). However, as noted by Newel1 and McDonald (1992), despite considerable interest among researchers and practitioners, clear guidelines for organizing practice sessions have yet to be formulated. Magill (1992) has argued that the practice schedule research provides a knowledge base from which guidelines can be developed. This research, ongoing for over a decade, has compared the effects of practice schedules, which represent levels of contextual interference, on the performance and learning of motor skills. Predominately laboratory based, this research has produced an impressive set of findings (for a review, see Magill & Hall, 1990). However, replication of these findings in applied settings has been difficult, and questions regarding the applicability of contextual interference have been raised (Newel1 & McDonald, 1992).