摘要:

Four environmental conditions contribute to climatic heat stress: ambient temperature, air humidity, air movement, and radiant heat from the sun and nearby warm surfaces. If sufficiently great, this climatic heat stress can adversely affect the performance of work or exercise. Particularly for endurance sport activities, such as marathon running, racewalking, and other sustained distance events, the ability to quantify the magnitude of heat stress is of value in helping both coach and athlete plan the safest competitive strategy. Quantification of climatic heat stress is possible through the use of three thermometers, which measure shade temperature (dry bulb temperature [DBT]), the effect of wind and humidity (wet bulb temperature [WBT]), and radiant energy (black globe temperature [BGT]). The three values are incorporated into a heat stress index (HSI), a temperature value comprised of 10% of DBT, 20% of BGT, and 70% of WBT. Extensive HSI monitoring was performed at the 1992 Barcelona Olympic Games, on‐site during all of the endurance competitions (10, 20, 50 km racewalks, marathons, and modem pentathlon cross country). These data provided the first in‐depth assessment of the extent to which the athlete is able to compete successfully under conditions ranging from high risk to extreme risk heat stress with minimal actual heat injury. This success is due in part to the adaptation in tolerating heat stress that occurs with training, as well as the instinctive reduction in pace adopted by the athlete to permit the optimum balance of skin and muscle blood flow that keeps core temperature from rising too high.

ISSN:1057-8315    

DOI:10.1080/15438629509512048

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

The physiological responses of 12 competitive swimmers to a standard training workout of four sets of six 100 m freestyle repetitions per set were measured in two trials. By random assignment the swimmers attempted to keep the workout constant in each trial by maintaining either a target heart rate (HR) or a target time for the 100 m efforts. The target HR or time was determined from these values measured at the anaerobic threshold (AT) during an initial determination of this exercise level. The HR after each repetition, 50 m split time, and blood lactate concentration after each set were measured throughout each workout for each swimmer. When target HR was used as the exercise criterion, the group mean (±SD) HR for the first set of six 100 m repetitions (173±11 beats/min) was significantly lower (p≤0.05) than the group mean AT target HR (182±11 beats/min), but the group mean HR for sets two, three, and four was not significantly different from the target value. Group mean lactate concentration after each of the four sets was not significantly different from the group mean value measured at the AT, although the group mean 100 m times for sets one and two were significantly faster (p≤0.05) than the speed corresponding to the AT. When target time was the exercise criterion, the group mean 100 m time in each of the four sets was virtually identical to the group mean target time, but the group mean HR and lactate concentration in each set were all significantly lower (p≤0.05) than the group mean values measured at the AT. It was concluded that target HR and target time were both reasonably, but not completely, successful as a method of controlling exercise intensity, because the predetermined physiological criterion response measured by the AT test were not replicated exactly during the workout because of the accumulating degree of fatigue experienced by the swimmers.

ISSN:1057-8315    

DOI:10.1080/15438629509512049

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

Locus of control, as measured by Levenson's scale, was assessed at preseason in 60 elite national‐level male and female basketball players. Information on frequency and severity of injuries was collected as the playing season progressed. When these data were treated by discriminant function analysis, it was found that neither gender nor any of the locus of control subscales (Internal, Powerful Others, Chance) could predict frequency or severity of injury. These findings, plus a critical analysis of other studies in this area, indicated that locus of control is not a valid predictor of sporting injuries.

ISSN:1057-8315    

DOI:10.1080/15438629509512050

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

Deep water running (DWR) is frequently used in rehabilitation from sport‐related injury. Blood pressure (BP) response to DWR has not been determined. The purpose of this study was to determine if a reliable baseline BP measure may be obtained from a deep water runner and to analyze BP response to DWR. Three testers took three counterbalanced BP measures on 30 subjects at restonland and in water. Generalizability theory was used to determine reliability. The systolic BP (SBP)‐reliability coefficient ranged from G = 0.96 for three testers and trials to G = 0.81 for one tester and trial. The diastolic BP (DBP) reliability coefficient was G = 0.93 for three testers and trials and G = 0.74 for one tester and trial, respectively. As a follow‐up, 37 women performed 30 minutes of DWR at 70% of maximum heart rate. Heart rate and BP were measured at rest on land, in water, and every 5 minutes during DWR. There were no significant differences (p>0.05) between resting land and resting water BP. A repeated measures ANOVA indicated a significant (p≤0.05) increase in SBP only during the first 5 minutes of DWR. Diastolic BP did not significantly change from rest. Results indicated that a reliable measure of baseline BP may be obtained and that the BP response to DWR is similar to the reported BP response to land‐based exercise of similar intensity and duration.

ISSN:1057-8315    

DOI:10.1080/15438629509512051

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

Fifty‐seven high school middle distance runners (39 male and 18 female athletes) were assessed for maximal steady‐state (MSS) running velocity (RV), RV at a heart rate inflection point (HRi), and a competitive 3.2 km RV (RV3.2km) for the purpose of determining the correlation between actual MSS RV (MSS RVOBS) and that estimated from the Conconi and LaFontaine field test A Pearson correlation of r = 0.66 (males) and r = 0.38 (females) was observed between MSS RVObsand MSS RV3.2km, and a correlation of r = 0.47 (males) and r = 0.09 (females), respectively, between MSS RVObsand HRiRV was recorded. A HRiwas detected in only 33 of 57 subjects (24 male and 9 female athletes). The respective LaFontaine and Conconi field tests overestimated a male's MSS RV, the former by an average of 13.4 and the latter by 7.7 m‐min‐1. A female's MSS RV, on average, was underestimated by 11.9 m.min‐1by the Conconi test and overestimated by 10.9 m.min‐1by the LaFontaine test The inaccuracy of the estimations ranged from 2 min 8 sec.km‐1to 3 min 43 sec.km‐1. The low association between observed and estimated MSS RVs, the inaccuracy of MSS RV estimation, and the absence of HRiin approximately 50% of the subjects suggest that these field tests are of little practical value in discriminating ability among the present group of high school middle distance runners.

ISSN:1057-8315    

DOI:10.1080/15438629509512052

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

A nationwide sample of 162 Australian elite and nonelite competitive female gymnasts were administered a questionnaire to collect personal and training data as well as information about the number, location, and type of injuries sustained in the previous 12 months. The gymnasts reported 321 injuries, a rate of 1.98 per gymnast (2.36 for the elite and 1.83 for the nonelite subjects). Of the total sample 78.4% reported sustaining one or more injuries (89.4% of the elite gymnasts and 73.9% of the nonelite gymnasts). Injuries to the ankle and foot (31.7%) were the most prevalent, followed by injuries to the lower back (15.0%). Sprains (29.6%) were the most commonly reported type of injury, followed by strains (20.6%) and growth plate injuries (11.5%). In terms of the amount of time lost due to injury, the elite gymnasts spent 20.2% of the year's training time at less than full capacity, compared with 13.9% for the nonelite gymnasts. These findings have implications for performance potential and training methods.

ISSN:1057-8315    

DOI:10.1080/15438629509512053

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

ISSN:1057-8315    

DOI:10.1080/15438629509512054

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

ISSN:1057-8315    

DOI:10.1080/15438629509512047

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor