Intrinsic Foot Strengthening (or The Foot Core)
The small muscles of the foot (a.k.a the foot core) are often overlooked when we rehabilitate a lower extremity injury. However, recent evidence has shown that strengthening these muscles can provide dynamic support to the foot and ankle in all standing activities. Many foot and ankle injuries benefit from increasing strength of the foot core: below are three exercises you can try.
A physical therapist can help individualize these exercises in addition to creating a treatment plan for you and your injury.
1) Short Foot Exercise. GOAL: to bring the ball of your foot closer to your heel by lifting the muscles in the arch of your foot.
2) Toes Spread Out. GOAL: maintain a short foot posture while lifting and spreading out all your toes, then placing only the big and little toe on the ground.
3) Toe Yoga. GOAL: maintain a short foot posture while alternating between picking up your big toe and picking up all your littles toes
Images from McKeon PO et al, 2015 and Lee DR et al, 2019.
References:
Sauer LD, Beazell J, Hertel J. Considering the Intrinsic Foot Musculature in Evaluation and Rehabilitation for Lower Extremity Injuries. Athletic Training & Sports Health Care. 2011: 3(1); 43-47. doi:10.3928/19425864-20100730-02
Lee DR, Choi YE. Effects of a 6-week intrinsic foot muscle exercise program on the functions of intrinsic foot muscle and dynamic balance in patients with chronic ankle instability. Journal of Exercise Rehabilitation. 2019;15(5):709-714. doi:10.12965/jer.1938488.244
McKeon PO, Hertel J, Bramble D, Davis I. The foot core system: a new paradigm for understanding intrinsic foot muscle function. Br J Sports Med. 2015;49:290. doi:10.1136/bjsports-2013-092690
Jung DY, Kim MH, Koh EK, Cynn HS, Lee WH. A comparison in the muscle activity of the abductor hallucis and the medial longitudinal arch angle during toe curl and short foot exercises. Physical Therapy in Sport. 2011;12: 30-35. doi:10.1016/j.ptsp.2010.08.001
Ferrari E, Cooper G, Reeves ND, Hodson-Tole EF. Intrinsic foot muscles act to stabilise the foot when greater fluctuations in centre of pressure movement result from increased postural balance challenge. Gait and Posture. 2020;79:229-233. doi:10.1016/j.gaitpost.2020.03.011
Kelly LA, Cresswell AG, Racinais S, Whiteley R, Lichtwark G. Intrinsic foot muscles have the capacity to control deformation of the longitudinal arch. J. R. Soc. 2014: Interface 11; doi./10.1098/rsif.2013.1188