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Forces exerted during exercises on the uneven bars. 在高低杠上练习时所施加的力量。
Medicine and science in sports Pub Date : 1979-01-01
J G Hay, C A Putnam, B D Wilson
{"title":"Forces exerted during exercises on the uneven bars.","authors":"J G Hay,&nbsp;C A Putnam,&nbsp;B D Wilson","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The purposes of this study were (1) to develop a technique to measure the force exerted on uneven bars during a gymnast's performance, and (2) to determine the magnitudes of the maximum forces exerted on the bars during normal use. Strain gages, a UV recorder, and motion-picture cameras were used to record the forces exerted against the bars and the motions with which they were associated. Three college gymnasts were used as subjects. Each performed several repetitions of an exercise sequence judged to result in the maximum loading of the bars she might produce under normal conditions. The maximum forces recorded were 3500 N (low bar) and 2140 N (high bar). These values were recorded during a sharp impact between the subject's thighs and the bar during the passage of the subject beneath the bar in a giant swing, respectively. Making due allowance for possible measurement error and for the estimated effects of the bars being used by gymnasts of greater mass than those in this study, it was concluded that bars should be designed to withstand repeated loads of at least 4205 N.</p>","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"11 2","pages":"123-30"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11694849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Football helmets and neurotrauma--an epidemiological overview of three seasons. 橄榄球头盔与神经创伤——三个赛季的流行病学综述。
Medicine and science in sports Pub Date : 1979-01-01
K S Clarke, J W Powell
{"title":"Football helmets and neurotrauma--an epidemiological overview of three seasons.","authors":"K S Clarke,&nbsp;J W Powell","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>During the 1975, 1976, and 1977 football seasons, the National Athletic Injury/Illness Reporting System (NAIRS) obtained records of the nature and severity of injuries and illnesses experienced by an annual average of 5361 high school and college athletes. Associated circumstances, including type and brand of helmets being worn by the injured and non-injured, also were obtained. From these data, and against specified epidemiologic criteria for significance, the possibility that particular helmets were associated unduly with cerebral and spinal neurotrauma was examined. The results revealed that (1) one permanent severe neurological injury (cervical spinal cord) was experienced, the mechanism of which was unrelated to helmet design; (2) cerebral concussions were infrequent (one significant concussion per 10,000 athlete exposures) and of a consistent rate from year to year; and (3) no particular helmet was associated with a disproportionate number of concussions or cervical spine fractures within those experienced. Continuing surveillance with multivariate analysis of possible causal relationships among all factors associated with these injuries is in progress.</p>","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"11 2","pages":"138-45"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11694851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Visual evoked potentials and signal detection following a marathon race. 马拉松比赛后的视觉诱发电位和信号检测。
Medicine and science in sports Pub Date : 1979-01-01
J A Gliner, J A Matsen-Twisdale, S M Horvath, M B Maron
{"title":"Visual evoked potentials and signal detection following a marathon race.","authors":"J A Gliner,&nbsp;J A Matsen-Twisdale,&nbsp;S M Horvath,&nbsp;M B Maron","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Five marathon runners participated in a visual sustained attention experiment 1 week prior to a competitive martathon race and from 1.5 to 8.5 h following the race. The task was designed to help assess changes in central nervous system function by examinining both behavioral deficits and electroencephalogram (EEG) visual evoked potentials as a function of the race. A significant increase in heart rate was observed during the behavioral task. No changes in any of the wave forms of the EEG visual evoked response were observed during the vigilance task as a function of the race. Sustained visual attention responses were unchanged for correct detections, but post-marathon performance gave significantly fewer false positive responses. The results provided evidence that central nervous system dysfunction was not observed following the completion of a competitive marathon race.</p>","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"11 2","pages":"155-9"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11694854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Overview of ventilatory control during exercise. 运动时的通气控制概述。
Medicine and science in sports Pub Date : 1979-01-01
G D Swanson
{"title":"Overview of ventilatory control during exercise.","authors":"G D Swanson","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Practically every respiratory physiologist of the last 100 years has studied the ventilatory response to exercise. Yet we still do not know the cause of increased ventilation associated with exercise. This overview considers the problem from a broad observational point of view. Data from studies combining exercise with continuous inspired CO2 and \"slug\" CO2 breathing imply a feed-forward/feed-back structure for the ventilatory controller. The feed-forward stimulus is correlated to CO2 production. Feed-back senses arterial CO2 tension and acts to minimize the effects of correlation errors and correlation slope errors in the feed-forward path. This feed-forward/feed-back structure yields a regulated arterial CO2 and a tight coupling of ventilation to CO2 production. The feed-back mechanism acts via the carotid body, and indirectly via the central chemoreceptor. A variety of mechanisms are discussed that may be involved in providing the feed-forward stimulus. In particular, the intravenous loading experimental results are considered in terms of an appropriate feed-forward stimulus.</p>","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"11 2","pages":"221-6"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11696969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Relationships of stroke rate, distance per stroke, and velocity in competitive swimming. 竞技游泳中划水速度、每次划水距离和速度的关系。
Medicine and science in sports Pub Date : 1979-01-01
A B Craig, D R Pendergast
{"title":"Relationships of stroke rate, distance per stroke, and velocity in competitive swimming.","authors":"A B Craig,&nbsp;D R Pendergast","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Competitive swimmers were asked to swim at a constant velocity (v) for short distances. They wore a collar to which was attached a fine non-elastic steel wire. The wire passed over two wheels of a device attached to one end of the pool. One wheel generated an impulse for every cm of forward movement and another wheel produced an electrical signal which was directly proportional to V. Measurements of distance and time were begun at definable points in the stroke cycle and were discontinued at the end of a predetermined number of strokes. In all of the four competitive strokes, front and back crawl, butterfly, and breaststroke, the V increased as a result of increasing the stroke rate (S) and decreasing the distance per stroke (d/s). In the front crawl, the male and female swimmers who achieved the fastest V had the longest d/S at slow S. The faster male swimmers also had greater percent decrease of the d/S at their maximal V than did the less skilled persons. The back crawl was similar to the front crawl except that maximal S and V were less. Increases of V of the butterfly were related almost entirely to increases in S. Except at the highest V, d/S was decreased somewhat. In the breaststroke increased V was also associated with increasing S, but the d/S decreased much more than in the other stroke styles. Fluctuations of velocity during the stroke cycle were least in the front and back crawl (+/- 15--20%) and greatest in the butterfly and breaststroke (+ 45--50%). The results were compared to the S observed and the values for V and d/S calculated for a large group of swimmers competing in the 1976 U.S. Olympic Trials. The implications of the findings for coaching swimmers are discussed.</p>","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"11 3","pages":"278-83"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11726314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Tennis: the effects of grip firmness on ball velocity after impact. 网球:击球后握力对球速度的影响。
Medicine and science in sports Pub Date : 1979-01-01
T Watanabe, Y Ikegami, M Miyashita
{"title":"Tennis: the effects of grip firmness on ball velocity after impact.","authors":"T Watanabe,&nbsp;Y Ikegami,&nbsp;M Miyashita","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The effects of grip firmness on the ball velocity after impact has been investigated in tennis. The average horizontal velocity of the ball prior to contact and after completion of contact was determined by a motion-picture camera. A tennis ball was fired from a machine to impact with a tennis racket, which was fixed in several different positions. No significant difference was found between the velocity of the ball after impact with a racket which was horizontally clamped and with a racket in a balanced, upright position. The velocity ratio (post-impact vs pre-impact velocity) was an inverse function of the velocity of impact.</p>","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"11 4","pages":"359-61"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11733173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Functional variability of the lower extremity during the support phase of running. 下肢在跑步支撑阶段的功能变异性。
Medicine and science in sports Pub Date : 1979-01-01
B T Bates, L R Osternig, B R Mason, S L James
{"title":"Functional variability of the lower extremity during the support phase of running.","authors":"B T Bates,&nbsp;L R Osternig,&nbsp;B R Mason,&nbsp;S L James","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The purpose of the research was to determine the variability of selected parameters during the support phase of running between consecutive right footfalls, and the included left footfall, as well as to acquire additional descriptive data on lower extremity function. Eleven college aged male runners were filmed (200 fps) from the rear and side while running on a treadmill at 4.29--4.47 m/sec. The statistical analysis of the mean absolute differences for temporal events between the three footfalls resulted in no significant differences. An estimate of event variability was calculated to be the actual time +/- 0.0110 sec or the percentage +/- 4.98% at the 95% confidence interval. Comparisons between the absolute deviations of selected body part positions and/or orientations for the test conditions resulted in no statistically significant differences. Estimates of variability ranging from 1.78--4.08 deg were calculated. Even though no statistically significant differences were obtained, the magnitude of the variability obtained for the parameters evaluated would seem to indicate a need for calculating representative or average values if subtle differences in lower extremity function are to be detected.</p>","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"11 4","pages":"328-31"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11733401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Considerations in organizing a multicentre study to examine effects of exercise on mortality and reinfarction in post coronary patients. 组织一项多中心研究以检查运动对冠心病患者死亡率和再梗死的影响的考虑。
Medicine and science in sports Pub Date : 1979-01-01
P A Rechnitzer
{"title":"Considerations in organizing a multicentre study to examine effects of exercise on mortality and reinfarction in post coronary patients.","authors":"P A Rechnitzer","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"11 4","pages":"364-5"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11733175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Tennis: the effects of grip firmness on ball velocity after impact. 网球:击球后握力对球速度的影响。
Medicine and science in sports Pub Date : 1979-01-01 DOI: 10.1249/00005768-197901140-00010
T. Watanabe, Y. Ikegami, M. Miyashita
{"title":"Tennis: the effects of grip firmness on ball velocity after impact.","authors":"T. Watanabe, Y. Ikegami, M. Miyashita","doi":"10.1249/00005768-197901140-00010","DOIUrl":"https://doi.org/10.1249/00005768-197901140-00010","url":null,"abstract":"The effects of grip firmness on the ball velocity after impact has been investigated in tennis. The average horizontal velocity of the ball prior to contact and after completion of contact was determined by a motion-picture camera. A tennis ball was fired from a machine to impact with a tennis racket, which was fixed in several different positions. No significant difference was found between the velocity of the ball after impact with a racket which was horizontally clamped and with a racket in a balanced, upright position. The velocity ratio (post-impact vs pre-impact velocity) was an inverse function of the velocity of impact.","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"5 1","pages":"359-61"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90359965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 18
Mitochondrial volume density in human skeletal muscle following heavy resistance training. 高强度阻力训练后人类骨骼肌线粒体体积密度的变化。
Medicine and science in sports Pub Date : 1979-01-01
J D MacDougall, D G Sale, J R Moroz, G C Elder, J R Sutton, H Howald
{"title":"Mitochondrial volume density in human skeletal muscle following heavy resistance training.","authors":"J D MacDougall,&nbsp;D G Sale,&nbsp;J R Moroz,&nbsp;G C Elder,&nbsp;J R Sutton,&nbsp;H Howald","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Needle biopsies were taken from triceps brachii of 6 healthy males before and after a 6 month intensive weight training programme. The tissue was sectioned, photographed under a Philips EM200 and subjected to stereological analysis. Cross sectional fibre areas were also calculated from cryostat sections stained for ATPase activity. Morphometric analysis indicated that training resulted in a significant 26% reduction in mitochondrial volume density and a 25% reduction in the mitochondrial volume to myofibrillar volume ratio. These changes were accompanied by significant increases in fibre area for both FT (33%) and ST (27%) fibres as determined from the light microscope. There was a significant correlation between the reduction in mitochondrial volume density and the increase in FT fibre area following training (r=0.845). It was concluded that heavy resistance training leads to a dilution of the mitochondrial volume density through an increase in myofibrillar size with hypertrophy.</p>","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"11 2","pages":"164-6"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11376223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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