The central nervous system utilizes tendon compliance of the intrinsic foot muscles to aid the foot's arch spring, storing and returning energy in its tendinous tissues. Recently, the intrinsic foot muscles have been shown to adapt their energetic contributions during a variety of locomotor tasks to fulfil centre of mass work demands. However, the mechanism by which the small intrinsic foot muscles are able to make versatile energetic contributions remains unknown. Therefore, we examined the muscle-tendon dynamics of the flexor digitorum brevis during stepping, jumping, and landing tasks to see whether the central nervous system regulated muscle activation magnitude and timing to enable energy storage and return to enhance energetic contributions. During step ups and jumps, energy was stored in the tendinous tissue during arch compression, and during arch recoil, the fascicles shortened at a slower rate than the tendinous tissues while the foot generated energy. During step downs and landings, the tendinous tissues elongated more and at greater rates than the fascicles during arch compression while the foot absorbed energy. These results indicate the central nervous system utilizes arch compression to store elastic energy in the tendinous tissues of the intrinsic foot muscles to add or remove mechanical energy when the body accelerates or decelerates. This study provides an adaptive mechanism used to enable the foot's energetic versatility and further indicates the value of tendon compliance in distal lower limb muscle tendon units in locomotion.

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