Peak torque and eccentric rate of torque development of the hamstrings might not be reflected by contractile properties measured by tensiomyography.

Background: Eccentric maximum strength and explosive force production of the hamstrings are crucial for performance in many sports. Tensiomyography (TMG has been shown to be a valuable tool to assess muscle contractility and function. For eccentric force production, neural activation has been proposed to be the predominant influencing factor. Nevertheless, high muscle fiber tension has to be generated. Therefore, this study aims to test the hypothesis that eccentric force production does not correlate with muscle contractility measured by TMG.

Methods: Twenty-three physical active males (26.09±3.25 years) performed maximal eccentric hamstring contractions at 210 °/s on an isokinetic dynamometer. Additionally, TMG measurements were conducted on the biceps femoris. Contraction time, delay time, maximal deformation and contraction velocity were derived and investigated. Spearman correlations between the TMG parameters and maximum torque, rate of torque development (RTD) and time to peak torque were calculated. Furthermore, Kruskal Wallis test was calculated for the TMG parameters between the top and bottom participants according to RTD.

Results: The correlation analysis showed no significant relationships between the TMG parameters and eccentric force production (P>0.05 for all comparisons). For the comparison between the high RTD group and the low RTD group, no significant differences in muscle contractility could be observed.

Conclusions: The results of the present study suggest that muscle contractile properties play a minor role in eccentric force production. Therefore, TMG measures seem not to be suitable to investigate eccentric behavior.