“No wind blows in favour of a ship without direction” (Seneca the Younger).
The function of the foot is not only support, but also control of the direction of body weight during locomotion (Rolian et al., 2009). Part 1 discussed the importance of foot shape in general for these purposes but the crucial role of the big toe deserves special attention.
The big toe is the rudder that provides directional control for body weight during weight bearing movement (Yavuz et al., 2009). It can do this only if correctly positioned. The notable spread of this toe from the others characterises habitually-barefoot populations (Hoffman, 1905; D’Aout et al., 2009; Shu et al., 2015) and is an evolved-functional adaptation providing directional stability. Chou et al. (2009) showed that constraining the big toe in an elevated position destroyed the ability to balance. Plank (1995) showed excessive pronation in walking when big toe position was compromised (squashed in), an affliction affecting 23% of 18-60 year olds and over 36% over 60 (Nix et al., 2010), and resulting from years of wearing shoes with restricted toe boxes (Munteanu et al.,2017).
The unique position and control of the big toe has evolved to direct body weight in walking and running. Compromised toe position creates instability and injurious loading at the foot, ankle and knee. The cure is simple:
Joe Nimble functional footwear is based on these concepts and this science.
Chou S, Cheng HK, Chen J, Ju Y, Wong MA. The role of the great toe in balance performance. Journal of Orthopaedic Research. 2009; 27:549-54.
D'Aout K, Pataky TC, De Clercq D, Aerts P. The effects of habitual footwear use: foot shape and function in native barefoot walkers. Footwear Science. 2009; 1(2):81-94.
Hoffman P. Conclusions drawn for a comparative study of the feet of barefooted and shoe-wearing peoples. The Journal of Bone and Joint Surgery. 1905; 3:105-36.
Munteanu SE, Menz HB, Wark JD, Christie JJ, Scurrah KJ, Bui M, Erbas B, Hopper JL, Wluka AE: Hallux valgus, by nature or nurture? A twin study. Arthritis Care & Research 69: 1421-1428, 2017.
Nix S, Smith M, Vicenzino B: Prevalence of hallux valgus in the general population: a systematic review and meta-analysis. Journal of Foot & Ankle Research3:21.
Plank M. The pattern of forefoot pressure distribution in hallux valgus. The Foot. 1995; 5(1):8-14.
Rolian C, Lieberman DE, Hamill J, Scott JW, Werbel W. Walking, running and the evolution of short toes in humans. Journal of Experimental Biology. 2009; 212:713-21.
Shu Y, Mei Q, Fernandez J, Li Z, Feng N, Gu Y. Foot morphological difference between habitually shod and unshod runners. PLoS ONE. 2015; 10:e0131385.
Yavuz M, Hetherington VJ, Botek G, Hirschman GB, Bardsley L, Davis BL. Forefoot plantar shear stress distribution in hallux valgus patients. Gait and Posture. 2009; 30(2):257-9.