Differences between Skeletal Muscle Contractile Parameters Estimated from Transversal Tensiomyographic and Longitudinal Torque Twitch Response

Contractile properties of skeletal muscle are studied for various purposes and mainly by means of force or torque twitch responses. This study compared contractile properties estimated from isometric longitudinal and transversal vastus lateralis twitch mechanical actions using torque and tensiomyography (TMG) as assessment methods, respectively. We calculated delay, contraction, sustain, half relaxation time and peak amplitude from the maximal twitch response obtained by both methods in 19 healthy males (age 46.1±17.8 years). Results indicated a shorter delay (∆=-23.4%; p<.001) and contraction time (∆=-42.7%; p<.001) when calculated from the transversal tensiomyographic actions, and shorter half relaxation time (∆=-26.2%; p=.025) when calculated from the longitudinal torque actions, while no difference in sustain time was found. Delay and contraction time did not correlate significantly when correlated between longitudinal and transversal actions; however, sustain time (r=.478; p=.038) and half relaxation time (r=.608; p=.006) did. In conclusion, the tensiomyography and torque gives different information reflecting that different mechanisms affect longitudinal and transversal twitch skeletal muscle deformations. Tensiomyographic response of skeletal muscle’s transversal actions likely reflects more intrinsic contractile properties.