Image from Liberal Dictionary of Zola Budd, known for racing and training barefoot.
She likely has/had good foot intrinsic muscle function doing all miles like that.
A great deal of focus in the rehab and performance world has been on core stability. Core training is commonly prescribed or utilized to improve proximal stability, reduce supposedly abnormal movements of the spine and pelvis and a variety of other reasons. I would go so far as to call this quite the fad in the fitness industry, as often the absurdness of the exercises can cause more issues than solutions (Sahrmann, 2010). As anyone with a decent understanding of kinesiology will know, the key is balancing the movements from the larger extrinsic muscles with the stabilizing forces of the small intrinsic muscles. For the longest time, core stability was considered to be the most important aspect of performance and contribution of the extrinsic muscles was largely downplayed. Everything is important. Balancing out the forces is key. We know understand that everything is important. Core stability is important to create a stable proximal foundation for the extrinsic muscles to generate appropriate force and movement.
