Affiliations: [a] Medical Clinic, Department of Sport Medicine,
University of Tübingen, Germany | [b] Clinic of Orthopedic Surgery, University of
Tübingen, Germany | [c] Institute of Sports Sciences, Dept. of Biomechanics,
University of Tübingen, Germany | [d] Institute of Sports Sciences, Dept. of Biomechanics,
University of Stuttgart, Germany
Abstract: The correction of ``muscular imbalances'' is assumed to be important
in therapy of shoulder pathologies and muscular strengthening. However, it is
not clear how these imbalances should be defined and the extent to which
conclusions can be drawn, relevant to therapy and training. Statements on physiological strength ratios and deviations from
these are only possible using a valid and reliable measurement. Isokinetic
shoulder strength measurements can be considered validly isokinetic up to 180
^{\circ}/s. Differentiation between the various types of
work and movements is reliable within a test-retest variability of 15--20%. The
maximum torque serves as a reliable parameter and additional information is
obtained by determination of local muscle fatigue. In this context, important considerations are the test method and
especially positioning and fixation. However, the direct application of
isokinetically determined strength values in training and rehabilitation is
only possible when the exercise position agrees with the position during
measurement. This is usually not the case. Since isokinetic movements are
rarely if ever encountered in everyday living or sports, data obtained by these
methods can hardly be used for training management and should mainly be used as
a therapy control. Adequately reliable data on the strength ratio of shoulder movements
can be obtained within narrow limits by isokinetic strength measurements.
However, in spite of critical assessment of the methods, it is recommended that
isokinetic measurements should be uniformly performed in accordance with the
queries in order to guarantee comparability and interpretation. In addition
stress in everyday living and sports lead to specific changes which should
always be interpreted on the basis of method-specific criteria and
exercise-specific movements. Taking functional-anatomical and methodical
considerations into account, isokinetic measurements deliver valuable
information for training and therapy within the framework of medically and
scientifically founded strength diagnostics.
