The effects of toe grip training on physical performance and cognitive function of nursing home residents, Journal of Physiological Anthropology
FYI For our senior friends - toe grips totally work and help with roller skating spider legs on hardwoods : r/germanshepherds
Arch Foot Sole Five-Toe Grip Corrector, Foot Muscle Training Prevent Flat Feet, Fitness Lacing Yoga Muscle Relaxation, Lacing Device Foot Massage Foot