Affiliations: [a] Pôle de Médecine Physique et Réadaptation, CHU
Nantes, 44035 Nantes cedex 01, France | [b] Institut Régional de Médecine du Sport, CHU
Nantes, 44035 Nantes cedex 01, France | [c] Polyclinique de l'Atlantique, Avenue Claude Bernard,
44 819 Saint Herblain, France
Note: [] Address for correspondence: Pôle de Médecine Physique et
Réadaptation, Hôpital Saint Jacques, CHU Nantes, 44035 Nantes cedex 01,
France. Tel.: +33 2 40 84 62 11; Fax: +33 2 40 84 61 91; E-mail:
marc.dauty@chu-nantes.fr
Abstract: The purpose of this study was to define the test-retest
reproducibility of concentric and eccentric isokinetic measurements of shoulder
rotators. It was carried out at a 26 day ± 4 interval.
Fourteen healthy volunteer subjects (7 men and 7 women), aged between 40 and 55
years (47.5 ± 5.6 years), were included. Evaluation was carried out with a
Cybex Norm dynamometer and the reliability was calculated according to the
intra-class correlation coefficient (ICC 2.1). The protocol was randomised for
the shoulder and for sets of concentric (con) and eccentric (ecc) tests.
Concentric sets consisted of 5 movements of internal (IR) and external rotation
(ER) at the speed of 60°/sec. then
120°/sec. Eccentric performance was recorded only for
the external rotators, to determine the ratio ER_{ecc}/
IR_{con}. Results indicated excellent reproducibility
for the peak torque (0.91–0.98), total work (0.88–0.96) and average power
(0.83–0.94) in concentric muscle action for internal and external rotators and
in eccentric muscle action for external rotators at 60 and
120°/sec. On the other hand the strength ratio:
ER_{con} / IR_{con}and
ER_{ecc} / IR_{con} should be
interpreted with caution because of a lower reproducibility (ICC:
0.53–0.83). In conclusion, isokinetic findings relating to concentric and
eccentric performance of the internal and external rotators of the shoulder are
reproducible under the present protocol. These findings may serve for assessing
rotator cuff function at the age where the incidence of rotator cuff overuse
becomes a serious problem.
