摘要:

Thirty healthy men, aged 17.5–64.0, were assigned to matched treatment and control groups and evaluated on selected anthropometric and cardio-respiratory measures before and after a twelve week at work stair climbing intervention program. The only significant change in the treated group was a decrease of rear calf skinfold thickness. There were no significant changes within the control group, nor were differences between groups significant when taking the entire treatment group into account. When the treatment group was dichotomized according to the amount of weekly stairclimbing, the subgroup which climbed stairs the most showed significant aerobic improvements. The Baseline &OV0312;o2max was not significantly related to either pre-program stairclimbing habits or aerobic power improvements. A significant relationship was observed between baseline % body fat and pre-program stairclimbing. The correlation between pre-program and in-program stairclimbing was statistically insignificant. The experiment showed that 5500 kgm/clay stairclimbing (approximately 25 flights for a 70 kg man) could result in significant improvement of maximal aerobic power.

ISSN:0025-7990    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The purpose of this study was to evaluate the cardiopulmonary function and body composition of sedentary and highly active paraplegics. Four age-matched groups of men (n = 41) were studied: wheelchair-bound sedentary (WS), wheelchair-bound athletes of international caliber (WA), able-bodied sedentary (NS), and able-bodied athletes of national Israeli teams (NA). Although of similar height, WS were significantly (p<.05) heavier and more obese (skinfolds) than WA and NS. Maximal oxygen consumption (&OV0312;o2max arm), as measured during arm ergometry by direct open circuit spirometry, was significantly lower in WS (19.58 ± 5.53 ml/kg mm) than in WA (35.00 ±7.55). The latter had significantly higher &OV0312;o2max arm than did NS (25.79 ± 3.98). However, no significant difference was observed between WA and NA (38.05 ± 6.25). A similar trend, favoring WA over WS, was shown for maximal minute ventilation and maximal oxygen pulse. Functional lung volumes (FVC, FEV1.0, MBC) did not differ significantly between WA and WS. Heart rates at submaximal work loads were higher in WA than in NA, but markedly lower than in WS. Clear-cut conclusions can be obtained only by a longitudinal study, but these data suggest a marked decrement in cardiopulmonary functions, related to the oxygen transport system, in men whose lower limbs have been immobilized for years. A reversed trend is shown for paraplegics who regularly activate their upper limbs and trunk muscles.

ISSN:0025-7990    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Subjects tried to maintain 15%, 30% and 50% maximum voluntary contraction (MVC) of their handgrip for 60 sec and 70% MVC for 30 sec. When the subjects watched the tension record, they could maintain the contraction for the required time. However, without visual cues (uncued), the tests resulted in a tension decline. Ae-α1described the tension decline in the 15% tests, Be-β1the 70% test, while the form in the 30% and 50% tests was Ae-α1+ Be-β1. In all cases α and/or β were found to be dependent on the starting tension. The electrical activity obtained from surface electromyograms did not increase during the uncued tests which would be expected if muscle fatigue were involved in the tension decline. Instead the electrical activity was directly proportional to the decline in tension suggesting that the fall in tension was not due entirely to muscle fatigue. 15% MVC uncued tests in which fatigue is known not to be a factor also showed a tension decline. Precooling the hand in an attempt to alter sensory input produced no systematic change from the original uncued tests, indicating that sensory information from the hand was probably not a major factor in the tension decline. It is suggested that during the uncued tests the fast component of the tension decline may be related to a sensory adaptation involving the Golgi tendon organs. The slow component is due to forearm muscle fatigue which is related to the ischemia produced during the isometric contractions.

ISSN:0025-7990    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Six factor solutions (three orthogonal and three oblique) were used to extract factors from the inter correlation matrices of 47 motor performance and physical growth measures obtained on 71 hoys and 74 girls, ages six to 9.9 years. Twelve factors with eigen values in excess of 1.00 were extracted from both the boys' and girls' data. The six factors that accounted for a major proportion of the variance in both sexes were tentatively identified as (1) Strength-Power-Body size, (2) Gross Limb-Eye Coordination, (3) Fine Visual Motor Coordination, (4) Fat or Dead Weight, (5) Balance, and (6) Leg Power and Coordination. Similarity in the factor structures of the sexes was evident from the application of a procedure for the quantification of the relationships between factors extracted from data in different groups of subjects. With this sample of children substantial relationships were obtained between eight of the ten factors which were common to both sexes.

ISSN:0025-7990    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

An investigation is made into the subject of scoring tables for track and field with emphasis on the application of computers to calculate and output the tables. The resulting scoring tables represent an attempt to describe the effective quality of performance for track and field events. This paper is published in three parts. The first portion reviewed the historical development of scoring tables. This part concerns the theoretical foundation and development of a mathematical model. A set of underlying principles and construction guidelines are established as a basis for all scoring tables. In order to satisfy the goals, a model which includes an exponential term is developed. The concept of a zero olfset is introduced as a boundary value for the low-level performances. The final part concerns an evaluation of the model and an analysis of the point scores for different events.

ISSN:0025-7990    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

To determine the role of blood (low in limiting maximal metabolic rate, the contralateral femoral artery was annulated and the blood passed through a pump (controlled flow perfusion) or a bypass (self perfusion) to the artery feeding the canine gastrocnemiusplantaris muscle group (N = 15). After a period of self perfusion, the pumped flow was set at the spontaneous level. The muscle was stimulated at 4 or 5 twitches per second to produce a maximal metabolic rate and the pumped flow increased until the precontraction perfusion pressure was reached. After 5 minutes, the flow was increased (perfusion pressure around 200 mm Hg) and then the flow was returned to initial levels and subsequently decreased below this. Oxygen uptake (&OV0312;o2) was determined in the fifth minute at each flow level. Isometric tension was measured with a myograph. When the flow was increased above that during the initial contraction period, tension and &OV0312;o2increased above their initial levels. When returned to initial levels, tension and &OV0312;o2followed. Flows below this level resulted in &OV0312;o2and tension decreasing below initial levels. Autoregulation transients were present before and after contractions. It appears that maximal metabolic rate and contractile performance ofin situdog muscles with autoregulating vascular beds are normally limited by blood flow.

ISSN:0025-7990    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

To test the hypothesis that an intact nerve supply is essential to normal replenishment of muscle glycogen after exhaustive exercise, glycogen concentration in normal gastrocnemius muscles from guinea pigs exhausted 48 hr previously was compared to glycogen in contralateral muscles that had been denervated at the muscle or high in the thigh immediately after exercise. Each animal of another group underwent tenotomy of one Achilles tendon after exercise so that any effect of disuse could he distinguished from effects of denervation. All muscles were able to replenish glycogen to normal control values 48 hr after exercise and surgery; there were no significant (> .05) effects of any of the surgical interventions. Therefore, it appears that glycogen concentration in skeletal muscle 48 hr after exhaustive exercise is independent of both neural phenomena and muscle tension.

ISSN:0025-7990    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The effect of chronic endurance exercise on the emotionality of male albino rats was studied in five experimental groups: Controls, Runners, Walkers, Swimmers and Waders. Runners and Swimmers were trained for 8 weeks using programs which produced significant bradyeardia and cardiac hypertrophy. Walkers and Waders received comparable handling and exposure to the psychological aspects of the treadmill running and swimming routines hut were not physically trained. The Control group was allowed only home cage activity. After 8 weeks all animals were tested for their level of emotionality using the tunnel emergence test and the open field test. The emergence test was judged to he too stressful for the Sasco rat strain used in this study since many rats failed to emerge in one hour. Three measurements in the open field: urination, defecation and central squares also lacked power to discriminate emotionality because of their very low level of occurrence. The Control rats had significantly longer latency times, which indicates that the additional handling received by the other groups reduced their emotionality. The significantly larger number of total squares entered by the Runners and Swimmers supports the hypothesis that chronic physical exercise does function to lower emotionality in the rat.

ISSN:0025-7990    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The purpose of this investigation was to determine the effects of shoe type, playing surface, weight supported and stance position upon the torques developed at the shoe-turf interface. The study was predicated upon the assumption that many knee injuries are torque-related and due to foot fixation, either by rigid eleating or by excessive traction between the shoe and playing surface. A laboratory apparatus was designed to measure the torque developed by various shoe-surface combinations. Under investigation were 11 shoe types, three artificial surfaces and natural grass, two player weights, and two player foot-stance positions. Torque data were gathered using impact loading, with an impact energy that is probably often experienced under competitive playing conditions. Resulting data indexed the shoes according to the mean torques developed on each of the playing surfaces, and comparisons of torque data with field studies by other researchers suggested which shoe-surface combinations might be the most potentially hazardous.

ISSN:0025-7990    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The authors have studied the alterations in cleat-surface friction of AstroTurf associated with use and exposure. Three cleat types were studied on live year old turf and on an unused, unexposed turf sample of the same production butch. Tests were carried out with and against surface grain under wet and dry conditions. It was found that with use and exposure the surface friction of AstroTurf does change, affecting both player performance and safety.

ISSN:0025-7990    

出版商:OVID    

年代:1975

数据来源: OVID