Resting Electromyographic Triceps Surae Activity and Tonic Vibration Reflexes in Subjects with High and Average-Low Maximum Oxygen Uptake Capacities     

Robert S. Hutton  T. L. Doolittle 《Research quarterly for exercise and sport》2013,84(3):280-285

Abstract

This study was designed to investigate the effect of an interactive videodisc motor skill assessment training program on the development of preservice and inservice teachers' qualitative assessment proficiency on two motor skills: the overhand throw and catch. Twenty-seven preservice and 27 inservice physical education teachers were randomly assigned to one of three treatment conditions: interactive videodisc (IVD), teacher-directed (TD), or self-directed (SD). Motor skill qualitative assessment accuracy was evaluated on a pre- and post-test basis using a 50-item motor skill assessment accuracy test (10 performances rated on 5 components) for each skill. Analysis of covariance results indicated significant main effects for treatment for both skills. Post hoc tests revealed that for the over hand throw, the IVD and TD groups were superior to the SD group but not different from each other. For the catch, the IVD group was found to be superior to both the TD and SD groups. These findings are discussed in relation to the advantages of interactive videodisc in terms of efficiency and user independence and with comparable findings in other educational applications.  相似文献   

Digit ratio (2D:4D) and performance in elite rugby players     

M. Bennett  J. T. Manning  C. J. Cook 《Journal of sports sciences》2013,31(13):1415-1421

Abstract

The relative length of the second and fourth digits (2D:4D) is a putative marker for prenatal testosterone. Low 2D:4D has been reported to correlate with high performance in sport in general. Here, for the first time, we examine the relationship between 2D:4D and performance in elite rugby players. The 44 players (28 forwards, 16 backs) were drawn from the Ospreys Rugby Union Club and 44 age-matched controls. The measures of performance comprised age-adjusted number of international performances (caps) for Wales, a comparison of coaches' first-choice League team with others, and the number of tries scored by backs in club matches. Compared with controls, players were larger and had lower 2D:4D for the right and left hand. With regard to number of caps, players with low 2D:4D in their right hand and low right 2D:4D compared with their left (right ? left 2D:4D difference) had high numbers of caps. First-choice players did not differ significantly from second-choice players in their 2D:4D but they did have a lower right ? left 2D:4D difference than second-choice players. Low right 2D:4D and low right ? left 2D:4D difference were significantly linked with large numbers of tries. We conclude that low right 2D:4D and low right ? left 2D:4D difference are predictors of high rugby performance.  相似文献   

Hip adductor activations during run-to-cut manoeuvres in compression shorts: implications for return to sport after groin injury     

Ajit M.W. Chaudhari  Steven T. Jamison  Michael P. McNally  Xueliang Pan  Laura C. Schmitt 《Journal of sports sciences》2013,31(14):1333-1340

Abstract

Athletes at high risk of groin strains in sports such as hockey and soccer often choose to wear shorts with directional compression to aid in prevention of or recovery from hip adductor strains. Large, eccentric contractions are known to result in or exacerbate strain injuries, but it is unknown if these shorts have a beneficial effect on hip adductor muscle activity. In this study, surface electromyography (EMG) of the adductor longus and ground reaction force (GRF) data were obtained simultaneously on 29 healthy individuals without previous history of serious injury while performing unanticipated 45° run-to-cut manoeuvres in a laboratory setting wearing shorts with non-directional compression (control, HeatGear, Under Armour, USA) or shorts with directional compression (directional, CoreShort PRO, Under Armour, USA), in random order. Average adductor activity in the stance leg was significantly lower in the directional condition than in the control condition during all parts of stance phase (all P < 0.042). From this preliminary analysis, wearing directional compression shorts appears to be associated with reduced stance limb hip adductor activity. Athletes seeking to reduce demand on the hip adductors as they approach full return to activities may benefit from the use of directional compression shorts.  相似文献   

Practice and play as determinants of self-determined motivation in youth soccer players     

David T. Hendry  Peter R.E. Crocker 《Journal of sports sciences》2013,31(11):1091-1099

Abstract

Based upon predictions derived from the Developmental Model of Sports Participation, we tested whether hours in domain-specific play (self-led activities) and practice (coach-led activities) during childhood (~5–12 year) in an elite group of youth soccer players from the UK (N = 144) were related to motivation. Independent analysis of three different age groups (Under 13, 15 and 17 year) did not show relations between play and practice activities during childhood and global measures of motivation. However, secondary analysis showed that when controlling for years in soccer, years in the UK Academy system were negatively related to global indices of self-determined motivation (SDI) and positively related to controlled motivation for the oldest players. Despite predictions, there was no evidence that play during childhood was positively related to more SDI. Prospective research is recommended to enable more robust conclusions about the role of early developmental practice activities, especially early specialisation in a high-performance system, on both skill and psychosocial development.  相似文献   

Nutritional strategies for promoting fat utilization and delaying the onset of fatigue during prolonged exercise     

E. V. Lambert  J. A. Hawley  J. Goedecke  T. D. Noakes  S. C. Dennis 《Journal of sports sciences》2013,31(3):315-324

Carbohydrate ingestion before and during endurance exercise delays the onset of fatigue (reduced power output). Therefore, endurance athletes are recommended to ingest diets high in carbohydrate (70% of total energy) during competition and training. However, increasing the availability of plasma free fatty acids has been shown to slow the rate of muscle and liver glycogen depletion by promoting the utilization of fat. Ingested fat, in the form of long-chain (C 16-22 ) triacylglycerols, is largely unavailable during acute exercise, but medium-chain (C 8-10 ) triacylglycerols are rapidly absorbed and oxidized. We have shown that the ingestion of medium-chain triacylglycerols in combination with carbohydrate spares muscle carbohydrate stores during 2 h of submaximal (< 70% VO 2 peak) cycling exercise, and improves 40 km time-trial performance. These data suggest that by combining carbohydrate and medium-chain triacylglycerols as a pre-exercise supplement and as a nutritional supplement during exercise, fat oxidation will be enhanced, and endogenous carbohydrate will be spared. We have also examined the chronic metabolic adaptations and effects on substrate utilization and endurance performance when athletes ingest a diet that is high in fat (> 70% by energy). Dietary fat adaptation for a period of at least 2-4 weeks has resulted in a nearly two-fold increase in resistance to fatigue during prolonged, low- to moderate-intensity cycling (< 70% VO 2 peak). Moreover, preliminary studies suggest that mean cycling 20 km time-trial performance following prolonged submaximal exercise is enhanced by 80 s after dietary fat adaptation and 3 days of carbohydrate loading. Thus the relative contribution of fuel substrate to prolonged endurance activity may be modified by training, pre-exercise feeding, habitual diet, or by artificially altering the hormonal milieu or the availability of circulating fuels. The time course and dose-response of these effects on maximizing the oxidative contribution of fat for exercise metabolism and in exercise performance have not been systematically studied during moderate- to high-intensity exercise in humans.  相似文献   

Influence of Decision-Making on Attitudes,Creativity, Motor Skills and Self-Concept in Elementary Children     

Paul G. Schempp  John T. F. Cheffers  Leonard D. Zaichkowsky 《Research quarterly for exercise and sport》2013,84(2):183-189

Abstract

Attitudes, creativity, self-concept and motor skills were measured to determine the influence of decision-making on elementary children. Three groups of children (N = 208) were tested, one group was taught with the teacher dominating all classroom decisions, another group was encouraged to share in the decision-making, and a third group served as a control. Data were collected immediately before and after an eight-week instructional period. MANCOVA indicated that the two treatment groups had significantly higher scores than did the control group, and the shared decision-making group scored significantly higher than the teacher dominated group on measures of creativity, motor skills and self-concept. A 2 (treatment) × 2 (sex) × 5 (grade) ANOVA revealed significantly more positive attitude scores for children allowed to make decisions regarding their learning. Further, Pearson product-moment correlation showed the tested variables to be independent measures of a child's development.  相似文献   

Age Differences in use of Strategy for Recall of Movement in a Large Scale Environment     

Jerry R. Thomas  Katherine T. Thomas  Amelia M. Lee  Edwyna Testerman  Madge Ashy 《Research quarterly for exercise and sport》2013,84(3):264-272

Abstract

In order to investigate how children remember distance (route) and location (landmark) information, two experiments were conducted in a large scale environment using jogging as the means of locomotion. In Experiment 1, thirty 4-year-old and thirty 9-year-old children were randomly assigned within age to three groups which were cued prior to the jog to remember the event, location of the event or distance to the event. Results indicated that older children reproduced the location and distance better than younger children. Cueing children to remember the location resulted in more accurate estimates than the other conditions. In Experiment 2, 5-year-old, 9-year-old, and 12-year-old children (24 children of each age) were randomly divided into step counting strategy and control groups, and asked to reproduce a criterion distance jogged. Results indicated that the three strategy groups and the 12-year-old controls estimated distance with similar accuracy, but the 9- and 5-year-old controls were different, as their error was inversely related to age.  相似文献   

Role Conflict and the High School Female Athlete     

Joseph Anthrop  Maria T. Allison 《Research quarterly for exercise and sport》2013,84(2):104-111

Abstract

The primary purpose of this study was to assess perceived and experienced role conflict of high school female athletes in enacting the roles of female and female athlete. Data were collected on 133 high school varsity athletes by the use of a 33-item questionnaire designed to assess perceived and experienced role conflicts of the subjects, their socioeconomic backgrounds, and specific instances of encouragement or discouragement from significant others experienced during their athletic careers. Thirty-two percent of the subjects responded that they perceived little or no problem with role conflict, and 50% had experienced little or no role conflict. Seventeen percent of the subjects responded that they perceived role conflict to be a great or very great problem with 11% experiencing role conflict to the same degree. A chi square analysis of perceived and experienced role conflict computed for the entire group of subjects indicated that the athletes perceived greater role conflict than they had experienced (p<.01). A one way analysis of variance was performed comparing the means of the athletes in traditionally socially approved sports, those in non-traditionally socially approved sports, and those participating in both categories. Results indicated a tendency for those participating simultaneously in both socially approved and non-socially approved sports to have experienced more role conflict (p≤.07).

A distinction between internal and external role conflict was suggested as a method of understanding the different types of pressures with which the female athlete must deal.  相似文献   

At the Crossroads: Contributions of Response Selection Processes to Human Performance     

T. Gilmour Reeve 《Research quarterly for exercise and sport》2013,84(4):343-351

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Evaluative Criteria in Physical Education     

T. Erwin Blesh 《Research quarterly for exercise and sport》2013,84(2):114-126

Abstract

This study investigated the effects of iron supplementation (18 mg per day) on the serum iron, total iron binding capacity (TIBC), hemoglobin levels, and percent hemoglobin saturation with iron of female college basketball athletes. The serum iron and hemoglobin levels of ten varsity basketball athletes and seven control subjects (nonathletes) were measured (pretest) prior to the basketball season and again at the end of the season. Iron supplements, no supplements, or a placebo tablet were given during the 4-month experimental period. ANOVA statistical analyses revealed that the iron supplementation was of no value in raising serum iron, TIBC, percent saturation, and hemoglobin levels and that a 4-month basketball training regimen and season did not significantly lower serum iron and hemoglobin levels.  相似文献