Table 1.

EMG-to-MTU mapping

Recorded muscle EMG	Musculotendon unit (MTU)
Gastrocnemius medialis	gastrocnemius lateralis and gastrocnemius medialis
Tibialis anterior	tibialis anterior
Soleus	soleus
Vastus lateralis	vastus intermedius, vastus lateralis
Vastus medialis	vastus intermedius, vastus medialis
Semimembranosus	semimembranosus, semitendinosus
Biceps femoris	biceps femoris short head, biceps femoris long head
Rectus femoris	rectus femoris

Muscle groups from which experimental electromyography (EMG) signals were recorded and the associated musculotendon units (MTUs) in the computational modeling framework (Fig. 1c) that were driven by these EMG signals. In this study, the gastrocnemius medialis EMG also drove the gastrocnemius lateralis MTUs. The vastus intermedius EMG activity was calculated as the mean between the vastus lateralis and vastus medialis EMG signals. The long head and short head of the biceps femoris were driven by the same EMG signal. The same applied to the semimembranosus and semitendinosus