Estimation of lower limb muscle activity during jumps by using a musculoskeletal simulation model

Abstract

The purposes of this research are: Construct a musculoskeletal simulation model and calculate lower limb muscle activity and muscle force by using different types of jumping motions such as the change in initial posture and the presence/absence of arm swing. After that, the reliability and usefulness of the model are verified. This experiment is composed of a reliability verification experiment and a validity verification experiment, and each experiment is divided into two parts: a measurement experiment and a simulation. In the reliability verification experiment, SJ was performed from trials of two types of hip joint initial angles (1) Any initial knee flexion angle (Nom posture) and (2) Deep crouching posture (Deep posture), two types of arm swing motions (1) With arm swing (AS) and (2) Without arm swing (NAS) total of 4 conditions. In the validation experiment, (1) standing up from the Nom posture, (2) standing up from the Deep posture, and (3) performing a drop jump from a 38 cm. The simulation was analyzed using two models. The SJ was analyzed in two phases, the impulsion phase and the landing phase. The results of the reliability verification experiment confirmed that by using arm swing and deeper initial knee flexion angle, higher muscle activity, muscle output and jump performance was observed during SJ. Since these results are consistent with previous studies, it can be said that the model is reliable to some extent. In addition, the results of validation experiments showed that the simulation model overestimated muscle activity, but similar change curves were seen. We think that the simulation models are valid.