Medicine and science in sports最新文献_第3页

The nature of the perception of effort at sea level and high altitude. 在海平面和高海拔的感知努力的性质。

Medicine and science in sports Pub Date : 1979-01-01

D H Horstman, R Weiskopf, S Robinson

{"title":"The nature of the perception of effort at sea level and high altitude.","authors":"D H Horstman, R Weiskopf, S Robinson","doi":"","DOIUrl":"","url":null,"abstract":"The purpose of this study was to compare perceptual responses (RPE) and selected physiological measures during both short term and prolonged exercise of equal relative intensities at 4300 m to those at sea level. Specifically, we compared results obtained (n=20) for 6 min of exercise at 60, 80 and 95% VO2max and at 5 min intervals during exercise to exhaustion at 85% VO2max. At 4300 m, VO2max was reduced 19%, while VEmax and Rmax increased 17 and 8%, respectively. HRmax and RPEmax was unchanged. For any given relative exercise intensity, VO2 and absolute exercise intensity (kpm-min-1) were reduced, while VE was about 12% and R about 7% greater at 4300 m; HR was unchanged. At 4300 m, RPE at the lower intensities of submaximal exercise and early during prolonged exercise were significantly less than at sea level. These differences were reduced and finally eliminated as exercise intensity increased toward maximal or as prolonged exercise continued to exhaustion. Endurance time to exhaustion at 4300 m was not different from that at sea level. To account for the perceptual differences between exercise at 4300 m an sea level, we proposed that local factors (muscular strain) exert greater influence on the perception of effort at exercise intensities which do not greatly stress ventilation and circulation, while central factors exert greater influence on the perception of effort at exercise intensities at which tachypnea and tachycardia are of sufficient magnitude to be perceived as extremely stressful.","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"11 2","pages":"150-4"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11694853","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

The energy cost of cross-country skiing among elite competitors. 精英选手越野滑雪的能量消耗。

Medicine and science in sports Pub Date : 1979-01-01

J D MacDougall, R Hughson, J R Sutton, J R Moroz

引用次数: 0

Growth hormone response to continuous and intermittent exercise. 生长激素对连续和间歇运动的反应。

Medicine and science in sports Pub Date : 1979-01-01

A Karagiorgos, J F Garcia, G A Brooks

{"title":"Growth hormone response to continuous and intermittent exercise.","authors":"A Karagiorgos, J F Garcia, G A Brooks","doi":"","DOIUrl":"","url":null,"abstract":"We tested the hypothesis that human growth hormone (hGH) secretion during exercise is related to anaerobic metabolism, and therefore blood lactic acid (LA). Ten males (20 to 30 years) were observed during 40 min of continuous cycle ergometer exercise (CE, 45% of the minimum load which elicited VO2max), and during 20 bouts of intermittent exercise (IE, 1 min on/off at 2x the CE work rate). Continuous and intermittent exercises were used as these are known to result in different LA responses. Resting hGH was 1 to 2 ng/ml. After a lag period, hGH was significantly elevated by 15 min of exercise and thereafter rose continuously in both IE and CE. During IE hGH tended to be higher (12.1 +/- 1.4) than during CE (9.7 +/- 1.6 ng/ml, X +/- SEM), but the difference was not significant. In both exercise conditions free fatty acids demonstrated an initial fall and then a continuous secondary rise with higher peak values during CE (0.52 +/- .06) THAN DURING IE (0.39 +/- .05 mEq/l). Pyruvate (PY) and lactate rose initially during CE, but then declined before reaching steady levels. During IE, LA and PY increased continuously reaching values 3x greater than during CE. Alanine rose progressively during CE and IE, but was significantly higher during IE (442.2 +/- 29.3 vs. 367.9 +/- 30.9 muM). Glucose also tended to be higher during IE (4.67 +/- 0.32) than during CE (4.25 +/- 0.28 mM). Considering CE and IE either together or separately, no physiologically significant correlation was found between hGH and metabolite concentrations, rectal T, or O2 deficit. The results are interpreted to mean that hGH response to work is not directly related to \"anaerobiosis\".","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"11 3","pages":"302-7"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11727490","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

Compliance of post myocardial infarction patients to exercise programs. 心肌梗死后患者对运动计划的依从性。

Medicine and science in sports Pub Date : 1979-01-01

N B Oldridge

引用次数: 0

The effects of training: reinfarction and death--an interim report. 训练的效果:再梗塞和死亡——一份中期报告。

Medicine and science in sports Pub Date : 1979-01-01 DOI: 10.1249/00005768-197901140-00018

P A Rechnitzer

引用次数: 6

The synchronization of muscle activity and body segment movements during a running cycle. 在一个跑步周期中肌肉活动和身体部分运动的同步。

Medicine and science in sports Pub Date : 1979-01-01

B C Elliott, B A Blanksby

{"title":"The synchronization of muscle activity and body segment movements during a running cycle.","authors":"B C Elliott, B A Blanksby","doi":"","DOIUrl":"","url":null,"abstract":"Locomotor patterns of running were studied using computerization to synchronize electromyography (EMG) and cinematography (CMG). Surface electrodes monitored the muscle action potentials from rectus femoris, vastus lateralis, vastus medialis, biceps femoris, semitendinosus, semimembranosus, triceps surae and tibialis anterior muscles as 10 female subjects ran on a treadmill at speeds of 2.5 m/s and 3.5 m/s. Averaged integrated electromyograms were formulated to represent action potential levels for various sub-sections of the running cycle. Beginning at foot contact, the running cycle was dominated initially by muscle activity concerned with stabilization. The co-contraction of vastus medialis, vastus lateralis, semimembranosus, tibialis anterior, biceps femoris and triceps surae were associated with clockwise rotation (running from left to right) of the thigh, leg and foot in providing a stable base during the early support phase. Lower limb stabilization then gave way to the powerful driving thrust of the mid and late support phases. This period was characterized by increases in the activity levels from triceps surae and biceps femoris. The co-ordination of inertial effects and secondary muscular activity was associated with leg flexion as the thigh changed direction and with leg extension during the swing phase of running. This conclusion was supported by both EMG and resultant muscle moment of force date. Increased activity from semimembranosus and semitendinosus occurred with cessation of thigh flexion and leg extension prior to the subsequent heel strike. Tibialis anterior also eccentrically contracted to place the foot on the treadmill under control. The increase in the running speed was related to an increase in muscle action potential (in parts of the cycle) where the particular muscle was functional. This increase was paralleled kinetically by an increase in the resultant muscle moment of force level.","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"11 4","pages":"322-7"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11733400","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

Policy statement regarding the use of human subjects and informed consent. 关于使用人类受试者和知情同意的政策声明。

Medicine and science in sports Pub Date : 1979-01-01

引用次数: 0

Abstracts of the 1979 American College of Sports Medicine annual meeting and Pan Pacific Conference. May 24-26, 1979, Sheraton-Waikiki Hotel, Honolulu, Hawaii. 1979年美国运动医学学院年会及泛太平洋会议摘要。1979年5月24日至26日，夏威夷檀香山喜来登威基基酒店。

Medicine and science in sports Pub Date : 1979-01-01

引用次数: 0

Cardiac output during rest and exercise in desert heat. 沙漠高温下休息和运动时的心输出量。

Medicine and science in sports Pub Date : 1979-01-01 DOI: 10.1249/00005768-197901130-00002

L. Myhre, I. Oddershede, D. B. Dill, M. Yousef

引用次数: 1

Muscle fiber composition and performance capacities of women. 女性肌肉纤维组成与运动能力。

Medicine and science in sports Pub Date : 1979-01-01 DOI: 10.1249/00005768-197901130-00007

C. J. Campbell, A. Bonen, R. Kirby, A. Belcastro

{"title":"Muscle fiber composition and performance capacities of women.","authors":"C. J. Campbell, A. Bonen, R. Kirby, A. Belcastro","doi":"10.1249/00005768-197901130-00007","DOIUrl":"https://doi.org/10.1249/00005768-197901130-00007","url":null,"abstract":"The purpose of the present study was to determine whether the fast-twitch (FT) fiber composition in muscle was a) correlated with performance capacities, b) related to the trainability of the subjects, and c) whether the FT fiber composition could be predicted with standard laboratory tests. From twenty-four young women (ages 24.3 +/- 3.0 yrs) muscle biopsies were obtained from the vastus lateralis of both the left and right legs. In addition, each subject completed four laboratory tests: i) a maximal oxygen intake test on the cycle ergometer, ii) a high-kp power test, iii) a low-kp power test, and iv) a Sargent jump. Prior to training the correlations between %FT fibers and each of the tests (r equal to or less than 0.19) were not significant (P less than 0.05). After training anaerobically (N = 20) significant improvements (P less than 0.05) occurred in a) the high-kp test (delta = + 0.12 +/- 0.02 kpm/sec.kg) b) the low-kp test (delta = + 0.10 +/- 0.01 kpm/sec.kg) and c) the Sargent jump (delta = + 2.5 +/- 1.1 cm). However, these training-induced changes (delta) were not correlated with %FT fiber composition (r equal to or less than 0.35), nor were the post-training performances on the tests correlated with the %FT fibers (r equal to or less than 0.12). Performance capacities before and after training were not significantly different in groups with a low %FT fiber composition (35.8 +/- 1.6%) or a high %FT fiber composition (63.6 +/- 2.2%). None of the performance tests either singly, or in combination in a multiple regression equation, provided a suitable prediction of the FT muscle fiber composition. The results of this study indicate that athletic performances and/or susceptibility for training cannot be determined a priori from simple measurements of muscle fiber composition.","PeriodicalId":18528,"journal":{"name":"Medicine and science in sports","volume":"42 1","pages":"260-5"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77258015","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: 32