ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1992.tb00329.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The effects of different types of training and immobilization on muscle tissue have been studied intensively and have been well established. At the beginning of strength or power training, the increase in muscular performance can be explained by neural and psychological adaptation; that is, recruitment of more motor units per time unit, learning of more effective and economical usage of the active motor units and reduction of the inhibitory inputs to the active alpha motor neurons. After 6 to 8 weeks, further progress is due to gradual muscular hypertrophy, that is, a true increase in size of pre‐existing fibres. Today, the theory of muscular hyperplasia (new fibre formation by a splitting of existing fibres) is not supported in critical reviews. With endurance training, there is an increased concentration and volume density of muscle mitochondria with corresponding biochemical adaptation, allowing the muscle to produce more mechanical power output aero‐bicalry and to be activated for longer periods of time without being fatigued. Immobilization, in turn, atrophies the muscle very quickly, significantly already after one week. The most striking morphological findings are reduction in fibre size and diameter, reduction in the capillary density and a simultaneous increase in intramuscular connective tissue. At the same time, many harmful functional and biochemical effects also occur. Compared with muscle tissue, the knowledge of the effects of training and immobilization on tendon or ligament tissue is scarce and research has not been systematic. In animal experiments the tensile strength, elastic stiffness and total weight of a tendon or ligament have increased due to training (collagen fibre thickening) and decreased due to immobilization (fibre splitting and disorientation). These changes can be explained by an exercise (immobilization‐induced increase (decrease) in synthesis of collagen and proteogrycan‐water matrix due to increased (decreased) fibroblast activity. The effects of training on the myotendinous junction or proprioceptors (muscle spindles and Golgj tendon organs) are largely unknown. Our recent studies showed that immobilization is very detrimental to these organs morphologically as well as biochemically. Slowly progressing physical exercise causes meaningful adaptive changes in the articular cartilage: the cells and nuclei of chondrocytes enlarge and the proteoglycan content and cartilage thickness increase. However, if training is too strenuous or biomechanically misloading, a degeneration process of the cartilage may begin, which is also the case in an immobilized joint Bone tissue adapts to weight‐bearing and muscular work well by increasing bone mass and density, most probably through osteoblast stimulation. The remodelling cycle of bone tissue is, however, a slow process, taking at least several months to occur. The achieved bone mass is also dependent on genetic, nutritional and hormonal factors. Immobilization, on the other hand, causes exactly the reverse effects on bone tissue and may finally (that is, after 5 to 6 months) lead to irreversible ost

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1992.tb00330.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

What is Danish in Danish football? The question marks a new horizon in the sociology of identity in an era of internationalization and Europeanization. But it also challenges us to find new methods of analyzing cultural particularity and societal relativity in body culture. Starting from differentiations betweenroligan(peaceful fan)vshooligan anddyst(jousting)vssport, the study proceeds from the class body over the configurations of space, time and product towards gender aspects and the culture of laughter, ending at the level of “frying”, mystique and grace, at the phenomenological limits of what can be sociologically rationalized in body experience and body practice. But it is not least from this level (or this intermediary space) that the questions concerning identity in movement culture ar

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1992.tb00331.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The distribution of blood flow in the menisci was investigated in 23 anaesthetized mongrel dogs. The blood flow was determined by means of radioactive microspheres injected intracordially and reference samples were taken from the aorta at a constant rate of 2.5 ml/min. The menisci were dissected in separate parts and the gamma radiation of the specimens was counted in a scintillation counter to assess the blood flow. The rate of blood flow in the medial meniscus was 5.55 ml per 100 g per min in the peripheral part and 2.51 ml per 100 g per min in the inner part. The corresponding figures were 3.09 and 2.33 for the lateral meniscus. No significant differences between the anterior horn, the middle section and the posterior horn were demonstrated. In the medial meniscus the rate of blood flow was 9 times lower in the central part (0.30) than in the surface‐near part (2.78). In the lateral meniscus the rate of blood flow was 16 times lower in the central part (0.12) than in the surface‐near part (1.

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1992.tb00332.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The objective of this study was to compare a nonaugmented autogenous anterior cruciate ligament (ACL) graft with an autogenous graft augmented with Leeds‐Keio polyester mesh (L‐K mesh) when the augmentation was fixed to bone at both ends or fixed to bone at one end. Twenty‐six rabbits were divided into 3 groups (nonaugmented, augmented with one‐end fixation and augmented with two‐end fixation), and were evaluated 12 weeks postoperatively. The gross findings demonstrated adhesion of the proliferated infrapatellar fat pad to the reconstructed ACL in the autogenous group, but not in the augmentation groups. The microangiographic study revealed poor revascularization in the augmentation groups. Histologically, in the L‐K two‐end fixation group, the biological segment of the reconstructed ACL remained necrotic. The biomechanical study showed that the augmentation groups were significantly stiffer and stronger than the nona

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1992.tb00333.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Thirty‐four recreational atlethes with a mean age of 40 years were operated for a fresh subcutaneous rupture of the Achilles tendon with an approximating suture of the tendon in combination with 8 weeks in an equinus below‐knee plaster. The elongation of the tendon during the rehabilitation was measured radiographically with implanted steel‐wire indicators. The residual muscle function and the range of motion were recorded 1 year after the operation in 30 of the patients. There was no change in the passive range of motion and no elongation of the tendon during the primary healing period. The muscle function, measured with a special dynamic step test, was significantly impaired compared with the healthy side. Although the function was reduced in 17% of the patients, there was no subjective disco

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1992.tb00334.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

During one alpine skiing season injuries were registered prospectively among 951 Danish alpine skiers. The injury incidence was 19.4 injuries per 1000 skiing days, or 3.4 injuries per 1000 skiing hours. The incidence of injuries treated by a doctor was 5.9 injuries per 1000 skiing days, which is 2–5 times higher than previously reported. Lower extremity doctor‐treated injuries comprised 65% of the total and upper extremity doctor‐treated injuries 25% ‐ a distribution seen 25 years ago in alpine skiing countries. Only 18% of the thumb injuries were seen by a doctor. Neither age, preholiday training, self‐rated skiing ability, ski school attendance during the week nor the use of rented versus owned equipment significantly influenced the risk

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1992.tb00335.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Anxiety was assessed in younger and older adolescent athletes in an attempt to test aspects of Hanin's zone of optimal function theory. Sixty‐five participants in a track and field camp completed anxiety inventories at baseline and were instructed: 1) to recall how anxious they felt prior to their best performance and 2) to predict how anxious they would feel prior to an informal meet to be held 4 days later. Actual precompetition anxiety was assessed 1 h prior to the meet. Predicted precompetition anxiety was significantly higher than baseline and actual precompetition anxiety. Mean actual precompetition anxiety was not elevated above baseline. However, 34% (22/65) of the sample experienced high levels of precompetition anxiety, and the majority of these (17/22) reported performing optimally with high anxiety. Significant correlations between predicted and actual precompetition anxiety occurred for boys, but not for girls. The differences between predicted and actual precompetition values tended to be smaller in boys than in girls. Based on this sample, it is concluded that: 1) in accordance with the zone of optimal function theory, young athletes display considerable diversity in actual and optimal precompetition anxiety values; and 2) young athletes tend to overestimate the level of anxiety they will experience prior to an easy competitio

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1992.tb00336.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

A range of motivational characteristics were studied in a sample of 228 males and 124 females (age: 15–16 years) recruited from the most promising performers of different sports, mainly in western Norway. They all completed the Sport Orientation Questionnaire (competitiveness, win and goal orientation), the short Sensation Seeking Scale, the Life Orientation Test (optimism), a new scale on Social Reactivity (reactive and proactive negativism) and questions on the importance of friendship among sport performers and of being the best. Differences of motivational styles were tested between males and females, performers of endurance, explosive and team sports and moderately versus highly successful performers. The males scored significantly higher on competitiveness, win and goal orientation, sensation seeking and so‐called reactive negativism, but scored significantly lower than females on the importance of friendship. More complex group differences were also significant. One example is the relatively high mean score for proactive negativism in males performing explosive sports and the low mean in females of team sports. Our findings indicate a role for gender, type of sport, and level of excellence in motivational differences among these promising athletes. The prospective significance of motivational differences for future success in sport competitions will be tested in a follow‐up

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1992.tb00337.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

This report presents an occasion in which two lines were to be inserted and a vasovagal reaction was developed during insertion of the second catheter. Thus BP and HR were followed during development of vasovagal symptoms and during leg extension performed in an attempt to terminate the event

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1992.tb00338.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY