gms | German Medical Science

7th EFSMA – European Congress of Sports Medicine, 3rd Central European Congress of Physical Medicine and Rehabilitation, Annual Assembly of the German and the Austrian Society of Physical Medicine and Rehabilitation

Austrian Society of Physical Medicine and Rehabilitation

26.-29.10.2011, Salzburg, Austria

Profile of strength in shoulder rotator muscles during fatigue-resistance exercise in elite tennis players

Meeting Abstract

7th EFSMA – European Congress of Sports Medicine, 3rd Central European Congress of Physical Medicine and Rehabilitation. Salzburg, 26.-29.10.2011. Düsseldorf: German Medical Science GMS Publishing House; 2011. Doc11esm064

DOI: 10.3205/11esm064, URN: urn:nbn:de:0183-11esm0642

Published: October 24, 2011

© 2011 Julienne et al.
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Outline

Text

Objective: Internal Rotator muscles (IR) of the tennis player’s dominant shoulder display greater isokinetic peak torque (pT) during Maximal Voluntary Actions (MVC) than those obtained in the non-dominant shoulder, in contrast, the external rotator muscles (ER) do not show shoulder-related differences [1], [2], [3]. Nevertheless, tennis performance is not solely limited to MVCs but also requires the capability of maintaining a high level of strength while hundreds of shots during matches [4]. Thus, two previous studies showed that ER muscles were less fatigue-resistant than IR muscles without reporting shoulder-related differences [1], [5]. However, these studies did not indicate the progression of the conventional (ER/IR) and functional (ER eccentric/IR concentric) ratios which, make it possible to accurately quantify the muscular balance between IR and ER muscles. Thus, the aim of this study was to analyse the mechanical properties of IR and IR muscles and the progression of the conventional and functional ratios during a fatigue-resistance exercise in tennis players’ shoulders.

Material/Methods: PT produced by 8 elite tennis players were recorded before (pre-test), during and after (post-test) an isokinetic fatigue-resistance exercise. The pre- and post-tests were composed of 2 concentric and 2 eccentric maximal repetitions of internal and external shoulder rotations at the angular velocities of 60° and 120°.s-1. The fatigue-resistance exercise consisted of performing 50 concentric maximal repetitions (10 sets of 5 repetitions) of internal and external rotations of both shoulders at 120°.s-1. IR and ER pT were measured. Normalised IR and ER pT, conventional and functional ratios were analysed.

Results: During the fatigue resistance-exercise, the decrease in the normalised pT in the dominant shoulder was greater for ER muscles (–63.3%±12.4) than for IR muscles (–46.8%±7.90) (Figure 1 [Fig. 1]). In post test, there was a decrease in the conventional ratio (–3.1%±8.1) whereas no change was observed in the functional ratio.

Conclusion: According to previous findings, ER muscles were less fatigue-resistant than IR muscles [1], [5]. Consequently, this difference led to a decrease in the conventional ratio after exercise. According to literature, during MVCs, the decrease of this ratio underlines a muscular imbalance which, may be a cause of occurrence of injuries [1], [2]. Thus, to protect tennis players from injuries, it is recommended to perform conditioning and rehabilitation programs using resistive exercises to improve the fatigue-resistance capability of ER muscles.


References

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