COMPARISON OF THE INFLUENCE OF THREE TYPES OF MILITARY BOOT INSOLE UPON THE FORCE AND LOADING RATES EXPERIENCED IN DROP JUMP LANDING

Eight male subjects performed drop jumps from a 0.8 m high platform onto a force plate and landing forces were sampled at 1000Hz. Six jumps were completed wearing military boots fitted with three different insoles (Saran, Poron and Sorbathane), and also when barefoot. Comparison of the last five jumps in each case showed that mean peak forces were similar (7.5 BW) for all insoles, though the forefoot impact mean (±SE) loading rate was higher for Sorbathane (754 ± 77 BWs-1) than for Saran (552 ± 58 BWs-1) or Poron (636 ± 77BWs-1). Mean peak loading rates for Poron, Saran and Sorbathane from forefoot to heel contact were similar for Saran (249 BWs-1) and Poron (254 BWs-1) and slightly higher for Sorbathane (300 BWs-1). Barefoot peak forces and both forefoot impact and peak loading rate were less than when a boot was worn with an insole