摘要:

In order to maximize fluid and/or carbohydrate availability during exercise, in which performance may be limited by one or the other, the composition and ingestion pattern of a beverage can be adjusted accordingly. As carbohydrate concentration increases, the rate of gastric emptying decreases. With more highly concentrated carbohydrate solutions, the net fluid absorption of water in the intestine is also reduced, although lower concentrations of glucose containing carbohydrates (∼3‐7%) actually can stimulate net intestinal absorption. Increasing the osmolality of a beverage can reduce the gastric emptying rate, but it has a more profound effect on gastric and intestinal secretions. Hyperosmolality increases secretions and as such decreases the rate of net absorption. Sodium inclusion in a beverage is warranted not only to offset losses (primarily from sweat) but, moreover, to promote fluid absorption in the intestine and to increase fluid retention. Recommendations include maintenance of fluid balance by ingestion of sufficient fluids, immediately prior to and during exercise, to restrict body weight losses to ≤1%. Somewhat more concentrated carbohydrate solutions may be ingested when the risk of hypohydration is low and performance is limited by carbohydrate availability. With increasing carbohydrate concentrations, at least up to 18%, there is a greater rate of carbohydrate passage through the gastrointestinal tract. When carbohydrate concentrations exceed 5%, the type of carbohydrate (mono‐ or disaccharides, long chain polymers, etc.) is important as the osmolality increases with increasing concentration and decreasing chain length. Thus, when concentrations of>8% are warranted, based on energy demands, there is an advantage to using glucose polymer solutions, owing to a decrease in gastrointestinal secretions and, hence, an increase in rate of net fluid abs

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00421.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Seven elite marathon runners ran 60 min at 90–96% of their average competition speed, and 4 triathletes and one cyclist bicycled for 2.5 h at 55–65% of their max V02at 18°C and at 32°C in a climatic room. They drank 400 ml of either redistilled water or a 9% glucose polymer solution before start and every 15 min during exercise. The gastric emptying rate, sweat loss and metabolites in venous blood were measured. The gastric emptying rate limited the replacement of sweat loss. Despite an optimal fluid intake, the resulting dehydration for a whole marathon at 32°C would correspond to about 3% of body weight when drinking water (and 4.5% with glucose polymer) in the elite marathoner. Impaired performance and increased susceptibility to heat illness can be predicted in warm enviro

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00422.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The present study reports results on the effect of genes, individual and common environments on the variance of maximal aerobic power. Data on 436 identical and 622 fraternal male twin pairs in their late teens or early twenties were retrieved from the Norwegian Army Draft Board. Structural equation models were fitted to the mean squares within and between the twin pairs. The results indicate that more than half of the variance in maximum aerobic power is due to genotypic differences, whereas the rest is accounted for by individual (specific) environmental factors. The possibility of cohort and society differences in the heritability of maximal aerobic power is discussed.

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00423.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Physical exercise preserves bone mass. Measurements of bone biomarkers may reflect the events in bone during exercise. Fifteen healthy, well‐trained individuals (7 men and 8 women) performed a running test for 21 min until exhaustion. Venous blood samples were drawn before and 30 min after the exercise to measure the levels of osteocalcin, the carboxyterminal propeptide of type I procollagen (PICP) and the carboxyterminal cross‐linked telopeptide of type I collagen (ICTP). After exercise, the women had a marked increase in serum osteocalcin concentrations (from 7.5±5.0 μg/1 to 11.5±3.0 μg/1), whereas the level was unaffected in the men (from 14.5±3.0 μg/1 to 13.5±4.6 μg/l). In the men there was a marked increase in PICP (from 240±47 μg/1 to 268±56 μg/1) that was not seen in the women (from 244±70 μg/1 to 253±60 μg/1). In neither group did ICTP levels change. In conclusion, significant responses were seen in PICP and osteocalcin during exercise, indicating that such measurements may be valuable for the further delineation of the effects of physical activity on bone. Furthermore, the different responses in men and women point to interesting areas

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00424.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

A free radical‐scavenging preparation (pollen extract) or the corresponding placebo was given to 50 volunteers over a period of 4 weeks to test the hypothesis that muscle soreness is associated with the generation of free radicals. The increase in malonyldialdehyde and lactate immediately after exercise both in blood and in muscle tissue was significantly lower after treatment with the scavenging preparation. The same was true for the prolonged post‐exercise increase in creatine kinase over a 5‐day period. The post‐exercise glycogen content of muscle was higher in the pollen extract group, as were the subjective feelings of pain, oedema, discomfort and tension in the working muscle. We conclude that the beneficial preventive effect of pollen extract on post‐exercise muscle soreness and lowering of the concentration of lipid peroxides indicate that free radicals are probably involved in the development of muscle

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00425.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Factors associated with low‐back pain were sought by examining physical activity, low‐back pain reports and physical measurements in 86 athletes and 33 nonathletes, a total of 119 adolescents (52 boys and 67 girls). The athletic boys participated in team sports (19 in soccer and 17 in ice hockey) and the athletic girls in individual sports or dance (14 in gymnastics, 17 in figure skating, and 19 in ballet). All subjects answered a questionnaire on physical activity and pain history at the beginning of the study and at the 1‐year follow‐up. At the beginning of the study, the subjects also participated in quantitative measurements of anthropometry, flexibility (joint hypermobility and muscular tightness), and strength. In multivariate analysis, decreased lumbar flexion and hip flexor tightness at the baseline were predictive of low‐back pain among boys during the follow‐up. Among girls higher than average body weight at the baseline and low‐back pain during the 12 months preceding the baseline measurements were predictive of low‐back pain during the follow‐up. However, the differences between the groups with and without low‐back pain were small compared with the differences between different physical activity groups. In conclusion, attention should be focused on low‐back pain, which accumulates in adolescent athletes participating in individual sports, such as figure skating and gymnastics. Our results suggest that flexibility and strength measurements are weak predictors in determining

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00426.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

We examined 20 consecutively admitted athletes suffering from chronic shoulder pain for more than 6 months following a single shoulder trauma without dislocation. All had pain during loading, especially during over‐the‐head activities with a clicking sensation, and symptoms of dead arm were also present. On examination, 8 patients had decreased range of motion and 14 patients had a positive apprehension test. Three had signs of impingement. Diagnostic evaluation with special X‐ray, ultrasonography, magnetic resonance imaging (MRI) and arthroscopy identified IS lateral tears, 3 partial and 1 total rotator cuff lesions and 2 patients with synovitis of the rotator cuff with subacromial impingement. Three patients had tendinitis of the biceps tendon and 1 had a lesion of the greater tubercle. In conclusion, chronic shoulder pain after a single nondislocated shoulder trauma in athletes should be evaluated due to a possible intraarticular cause of the pain. MRI seems to be the most valuable noninvasive method of evaluating patients with chronic shoulder pain and should be performed before arthroscopy and operative proce

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00427.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

During 1990 and 1991, 9% of all sports injuries that required emergency care at the University Hospital of Umeå were caused by floorball. Seventy‐eight per cent of the injuries were minor (AIS 1) and 21% were moderate (AIS 2). Sprains of the ankle and knee joints were most frequent, constituting 30% and 11% of all injuries, respectively. Licensed players were affected in 14% of all floorball injuries, and 61% of these injuries occurred during a game. We found no difference in severity or type of injuries between licensed players and recreational players. Our data show that the number of floorball injuries is increasing and that the majority of these injuries are of minor severi

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00428.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The purpose of this study was to describe the changes in the use of time for physical activity among 10‐ to 64‐year‐olds in Finland in the 1980s and between different seasons in 1987–1988. Additionally, some results of international comparative studies on the use of time for physical activity have been included. The data for the Finnish population was based on two time‐use studies conducted in 1979 and 1987–1988 in Finland. The method used for the data collection was a time‐budget diary in which the respondents registered their use of time on different activities during the day nationwide. The results indicate that women's time use for physical activity as a mean value per day increased by 12.5%, whereas men's total use of time for these activities remained unchanged. The seasonal comparison showed that the least time for physical activity is used in winter, when the time used for watching television and for passive leisure are at

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00429.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY