Balance der knieumspannenden Muskulatur: Isokinetische Diagnostik und trainingsinduzierte Optimierung

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The muscle balance between knee flexors and extensors plays a performance-limiting role in all sports which involve running or sprinting. Furthermore, balanced muscular capacities contribute to a targeted prevention of thigh and knee injuries such as hamstring strains or anterior cruciate ligament tears. Isokinetic dynamometry is considered to be the gold standard in assessing the muscular balance around the knee joint. However, there is a current lack of established test protocols and relevant test parameters which possess a good validity to quantifiy training adaptations and to prevent injuries. The following research programme incorporates six empirical studies which verify the application of a new isokinetic assessment tool and its derived test parameters to examine knee muscle balance.
These empirical studies demonstrated a generally high reproducibility of the obtained isokinetic data. Reproducibility significantly varied with regard to muscle group, contraction mode and test parameters, whereas angular velocity showed no influence on reliability. With the aid of hand grips, parti­cipants were able to produce maximal peak moments and contractional work during concentric and eccentric knee extensor tests. Straps at the knee and hip joint improved axis alignment by minimising evasive movements. The conventional and functional hamstring:quadriceps ratio revealed similar reliability scores as the dynamic control ratio at the equi­librium point. Since the latter parameter seemed to comprise a high practical relevance, its application and interpretation is recommended. In contrast to the functional hamstring:quadriceps ratio, the dynamic control ratio at the equilibrium point demonstrated a positive effect of long-term specific training and strongly correlated with the peak moments and contractional work obtained from eccentic isokinetic knee flexor tests. Knee muscle balance was signifcantly improved by a four-week selective eccentric knee flexor training consisting of standardised Nordic Hamstring Exercise. In spite of a slow training velocity, the biggest adapations emerged at the highest tested angular velocity two weeks after the training period ended.
The present research programme reveals systematic results obtained from a new isokinetic assessment tool. It was able to evaluate the knee muscle balance and to quantify its training-induced optimisation with a high practical relevance. The prognostic validity of the dynamic control ratio at the equili­brium point has still to be verified by conducting a multidimensional research approach.
Original languageGerman
Place of PublicationKöln
PublisherDeutsche Sporthochschule Köln
Number of pages166
Publication statusPublished - 2018

ID: 3254022

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