ABSTRACT
The aim of this investigation was to study the relationships between the rotators cuff of the shoulder during an exercise bout conducted in front crawl in a flume. Nine male swimmers realised a 400 yards front crawl at their maximal intensity. Electrical activities of six rotators of the shoulder were recorded using dual fine wire electrodes during the first and last five seconds of the test. The electrical signal was integrated, averaged at 50 Hz and normalized in relation to the maximal dynamic contraction obtained during the swim for each subject. Data analysis used standardized principal component analyses. Results showed a great discrepancy between the subjects, underlining the individual electrical responses of the studied population. No predominance of a muscular group (external or internal rotators) was observed. The relationships between the muscles were different at the beginning and at the end of the test. As a result, the activity of an external (or internal) rotator could not be assumed as representative of the activity of other external (or internal) rotators. Muscles could be activated all through the phases with different functions, which could not be identified using the EMG methods.
