Concept d'équilibre agonistes / antagonistes de l'épaule

Besides the concentric classical ratios, the eccentric isokinetic assessment of the muscle shoulder allows us to build some specific ratios.

The mixed ratio combines the eccentric maximal contraction of the external rotators (ER) and the concentric maximal strength of the internal rotators (IR). The mixed ratio is frequently decreased among overhead athletes. This imbalance could rise to shoulder tendinopathy, but seemed to be linked with field performance.

The functional ratio corresponds to the balance between the ER in concentric mode and the IR in eccentric contraction. The unstable shoulder shows a trend to lower functional ratios, highlighting the weakness of the eccentric IR in that pathology.