Final answer:
The plantar group of intrinsic muscles and the plantar aponeurosis are responsible for supporting the foot's longitudinal arch. These structures are critically involved in absorbing impacts and facilitating movement.
Step-by-step explanation:
The plantar group of intrinsic foot muscles, along with the plantar aponeurosis, plays a pivotal role in supporting the foot arch, particularly the longitudinal arch.
The foot arch is a complex structure that absorbs the impact and helps in energy distribution during weight-bearing activities like walking and running. The plantar aponeurosis, a deep fascia running from the calcaneus bone to the toes, is a key structure supporting the longitudinal arch of the foot. On the other hand, the intrinsic muscles of the foot are divided into dorsal and plantar groups, with the plantar group being organized into four layers which help in maintaining the foot's arch and contributing to toe movements. The intrinsic muscles augment the mechanical support by contracting to control the tension and elasticity of the arch, making it a dynamic stabilizer for the complex mechanics of the foot.