摘要:

Recent reports suggest that aerobic performance at very high levels may be limited by the pulmonary system. The purpose of the present study was to compare respiratory functions at rest and during graded maximal aerobic exercise (cycle ergometry) between well‐trained (TR,n= 11) and untrained (UT,n= 14) individuals while breathing atmospheric air, normoxic helium (He) and oxygen‐enriched mixture. When the subjects breathed air, TR exhibited lower exercise ventilatory reserve (MVV‐VEmax), ratio between minute ventilation (VE) and oxygen uptake (Vo2) and SaO2than UT. Breathing HE resulted in an increase in VE and Vo2maxin both groups but in an increased VE/Vo2and SaO2and maximal mechanical cycle ergometer load, only in TR. Compared with air, breathing an oxygen‐enriched mixture resulted in increased peak exercise SaO2and maximal mechanical load in both groups. It is concluded that arterial O2desaturation secondary to a relative hypoventilatory response may limit Vo2maxand aerobic performance capacity at high work

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1993.tb00367.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Capillary morphometrics in human skeletal muscle has been limited by technical problems in visualization. The purpose of this study was to develop a method for identifying capillary endothelium at the light level of resolution and to reassess the skeletal muscle capillarity in trained and untrained subjects. A lectin system of biotinylatedUlex europaeusI (UEA‐I), a vascular endothelial marker, provided a stain dense enough for direct computer‐aided image analysis. A morphometric comparison was made between Andersen's periodic acid‐Schiff and the UEA‐I capillary stains on tissue sections of human skeletal muscle. When identical fibers from adjacent sections were compared, the capillary density was 6% and cap fiber was 9% greater using the lectin method. Biopsies from 17 cross‐country skiers were compared with those of 8 age‐matched sedentary controls. The capillary density in the triceps muscle for the skiers was 536.1 ± 33.1 compared with 296 ± 17.7 for the controls. Longitudinal profiles that appear in skeletal muscle cross‐sections suggest a more isotropic (random orientation) configuration of the capillary bed than proposed by the Krogh model. There were 50.6% more longitudinal profiles in the trained samples. The UEA‐I lectin appears to be a valid and potentially useful marker for computerized image analysis of non‐pathological vascular endothelium, and the differences in capillarity between trained and untrained individuals may be greater than

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1993.tb00368.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The electromyographic activity of the peroneus longus and brevis muscles was recorded during 100 strides of walking and running on a treadmill in 9 experienced runners with and without an inversion restricting external ankle support. The duration of peroneal activity in the stance phase increased from median 61% of this stage when jogging to 88% when running fast. Pre‐heel‐strike activity was present in median 10% of all strides when walking, in 28% when jogging, in 40% when running at a medium pace and in 45% when running fast. Application of an external ankle support reduced pre‐heel‐strike activity by 50% for jogging and medium‐pace running. Our results suggest that an unacceptable degree of inversion of the ankle/foot complex in late swing phase produces a stimulus for peroneal muscle contraction before the foot is loaded at he

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1993.tb00369.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Forty‐nine previously sedentary women, mean age 30 ± 91 years, participated in this study of the relative importance of strength training resistance. The total work was the same in each group, but the work intensity (85%, 50% and 25% of one repetition maximum, 1‐RM) and number of sets (3 sets × 5 repetitions, 5 sets × 5 repetitions and 10 sets × 5 repetitions) varied. During 8 weeks, the subjects trained their leg extensor muscles and forearm flexors and extensors 5 times a week Body weight, body mass index, body fat, and thigh and forearm girth remained unchanged. All of the groups showed a significant increase in the maximal isometric strength of the leg extensors (15.5‐25.4%) and forearm flexors (9.3‐14.5%) and extensors (17.5‐19.0%). There were no differences between the groups in strength gain. Equivolume strength training with different resistances improved the maximal isometric strength of previously sedentary

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1993.tb00370.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

A standardized trauma was inflicted to the lateral side of the calf muscle of 12 New Zealand rabbits, creating a muscle hematoma without external bleeding. The acute hematoma was evaluated within 3 h with radionuclide imaging of red blood cells labelled with99mTc pertechnetate, ultrasonography and magnetic resonance imaging (MRI). The results were compared with the total volume of the hematomas as calculated from histological preparations of each injured muscle. Scintigraphy and T2‐weighted MRI accurately detected all hematomas but the calculated volume did not significantly correlate with histology. T1‐weighted MRI did not detect the hematomas. Ultrasonography detected all hematomas and also accurately evaluated the volume. In conclusion, scintigraphy, MR imaging and ultrasonography are all sensitive enough to detect an acute muscle injury, but in this investigation only ultrasonography accurately quantified the volume of the hemat

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1993.tb00371.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

On the basis of case records, the injuries of a female and a male university basketball team were examined over a 5‐year period. The female team had more clinic visits, physiotherapy and rechecks. Men sustained more new injuries. The body part most frequently injured on both teams was the foot/ankle, followed by the knee. Women had more injuries and rechecks of the knee than men, while foot/ankle injuries required more rechecks among men. It is suggested that women had more rechecks due to more severe injuries, greater anxiety and greater acceptance of rechecks offered. Possible explanations for the greater number of new injuries in men could be greater body mass, a higher degree of contact and lesser flexibilit

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1993.tb00372.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Evans tenodesis is one of the techniques used much for correcting the chronic lateral instability of the ankle. Long‐term results (average follow‐up 8 years) are reported for 113 operations on 109 patients. It is concluded that the method used gives a good functional result when the major complaint is recurrent sprains of the ankle. Functional stability does not necessarily correlate with mechanical stability when tested clinically or by radiogra

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1993.tb00373.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The concentration of cartilage proteoglycan fragments in knee joint fluid was measured before and after one event of physical exercise in 33 healthy athletes. Nine athletes ran on a treadmill for 60 min, 16 ran on road for 80 min and 8 played one soccer game (90 min). Before exercise, the levels of proteoglycan fragments in the athlete joint fluid were lower than in a previously analyzed reference group. After exercise, the concentration of proteoglycan fragments increased in all of the 7 athletes that could be directly compared before and after exercise. This increased concentration of proteoglycan fragments in the joint fluid could be an effect of mechanical loading of the cartilage in combination with a possible high turn‐over rate of the cartilage matrix in the athlete

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1993.tb00374.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

A case of an apophysiolysis of the ischial tuberosity in a 13‐year‐old female recreational iceskater is described. Despite slight dislocation, the patient developed hyperplastic callus and signs of fibrous healing after 13 months. She was, however, only bothered by this to a minor degree after prolonged sitting. The injury mechanism and possible predisposing factors as well as the controversies in the literature about treating this condition are discussed. The condition may be overlooked in several instances. We suggest that a pelvic X‐ray examination be performed in people from the age of 12 to 25 with a history of gradual pain around the ischial tuberosity after vigorous activities in sports implying repetitive stretching of the hamstrings or after an acute injury from a momentary stretching of the hamstrings with tenderness on palpation of the ischial tuberosity. Treatment depends on the degree of dislocation and on the functional requirements of the pa

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1993.tb00375.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Perceived coach's behavior in competition is analyzed in terms of a coach's positive, negative, or lack of response, which expectedly or unexpectedly follows a player's successful or unsuccessful action or is independent of player's action. The perceived contribution of these variables to extreme psychological arousal states (crisis, noncrisis) was investigated. Thirty‐seven elite ball‐game players estimated the occurrence probability of all Bayesian combinations among these variables under crisis and noncrisis conditions. Under crisis, a negative response, an unsuccessful action and unexpected events were more probable, whereas under noncrisis, the reverse is true. The athlete's psychological state was related particularly to the coach's response. The results are discussed theoretically in reference to the crisis constr

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1993.tb00376.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY