The American journal of sports medicine
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To quantify normal biological variability of shoulder abduction strength testing with an isokinetic and a hand-held dynamometer, we tested nine healthy subjects over a clinically relevant period. One side was tested with a Cybex at 60 deg/sec and the other with a hand-held dynamometer. Six maximal trials, following warmup, were conducted on each of 5 days, separated by 1 to 2 weeks. ⋯ In conclusion, intraday/interday correlations were high for Cybex and hand-held dynamometer. Interday variability was minimized by using the mean score of the first three and last three repetitions for Cybex and hand-held dynamometer, respectively. Changes in Cybex and hand-held dynamometer strength of less than 19% and 11%, respectively, are within the area of "measurement error" and should therefore not be considered clinically significant.
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Protecting the cervical spine in situations of axial compressive loading is indeed complex. Results from a number of crash simulations suggest that the mechanisms of head impact causing brain damage and those causing neck injury are different. The idea that neck injuries can be predicted from results of helmet drop tests or that the helmet is capable of providing protection to the cervical spine is unsupported. ⋯ The helmet does not have a large influence. To be effective, the helmet would have to be much less stiff than it is at present and would have to maintain this low stiffness under very large loads. These conditions would be difficult to achieve without making the helmet disproportionately larger than it is now.
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A survey of all amateur boxing matches in Denmark was made during a 3 year period. Data was gathered on means by which bouts were ended by the referee or attending physician, such as knock outs or blows to the head. A total of 5272 matches were fought: 3240 were senior matches (over age 19) and 2032 were junior matches (ages 17 to 19). Prophylactic intervention--unlimited length of hand bandage, voluntary use of boxing helmets, and heavier gloves for boxers greater than 149 pounds--did not affect the frequency of matches being stopped because of knock outs or blows to the head.