Pointe shoes, which elongate a dancer’s legs and accentuate the beauty of classical ballet technique, come with their own set of biomechanical principles—and their own set of risk factors for lower extremity injury.
     Dancing on pointe requires complete plantar flexion of the foot and ankle to a combined minimum of 90^o.² Dancers will achieve full relevé (dancing on the tips of the toes in pointe shoes, or on the metatarsal heads in ballet slippers) by either stepping directly into relevé or by rolling through the feet and rising to relevé with or without a demi-plié (feet are turned out, knees maximally flexed without raising the heels). The ankle is stable in the full pointe position because the posterior lip of the tibia locks onto the calcaneus and the subtalar joint is locked with the heel and forefoot in varus.⁶ The vamp, sole and closed pack position of the foot in the pointe shoe play a major role in stabilizing the midfoot while on pointe.⁷ 
      Simply walking in pointe shoes doubles the peak pressures acting on the foot compared to barefoot (41 N/cm² vs 86 N/cm²).⁸ Rising into the relevé position from a flat footed position increases the peak pressure to 115 N/cm².⁸ The dancer’s body weight is supported on the tips of the toes, which are in a relatively neutral position relative to the longitudinal axis of the foot.⁷ The average pressure on the toe box while on pointe is 220 psi or 1.5 MPa.⁹ The majority of the weight is borne by the first toe (0.14 – 0.58 MPa) regardless of the length of the second toe.⁸ In dancers with tapering toes, capping the second toe increases the pressure absorbed by the second toe but does not significantly change the pressure on the first toe.⁹
      Pointe shoes absorb some of the impact from jump landings, but the load is also distributed through the foot and ankle complex. One study compared five popular pointe shoe styles and found that the compressive strengths of the shoes were 4300 N or less.⁵ A 60-kg ballerina landing on pointe from a height of one meter generates an impact force of approximately 4950 N or 700 psi.⁵ This increased force could be a risk factor for the development of injuries, but has not been studied.

(Source: theballetblog)