Do thicker midsoles increase shock attenuation and do thin midsoles facilitate propulsion during lunge maneuvers? Footwear design for racket-sport industry

Reducing the thickness of the midsole layer rather than other components may enable shoe minimalism in manufacture to be more efficiently realized. The effect of midsole thickness on the biomechanical characteristics of lunges is limited. The current study investigated the effect of midsole thickness on temporal-spatial movement characteristics, ground reaction force variables and frontal foot and ankle kinematics during lunge maneuvers performed in a controlled laboratory setting. Sixteen badminton athletes were recruited to perform lunge footwork while wearing shoes with three midsole thicknesses. A force plate embedded in the floor was used to collect ground reaction force data. A kinematic analysis was conducted using a multisegment foot model. Temporal-spatial parameters, ground reaction force variables and frontal foot and ankle kinematics were calculated. Comparisons of the calculated variables among shoes with three midsole thicknesses were compared using a three-by-one repeated-measure analysis of variance (a = 0.05). Elite badminton players maintained similar temporal-spatial characteristics while wearing shoes with midsoles of various thicknesses (P>0.05). The peaks of the initial impact, early loading, and later propulsive forces did not vary among the midsole thickness (P>0.05). Greater pronation at the midtarsal joint during lunges performed while wearing shoes with thick midsoles (P<0.05) may be associated with a greater risk of adverse stress on soft tissue because of overuse. The kinematic evidence suggested that foot support can be enhanced by thickening the midsole. Furthermore, sport shoe models with thicker midsoles should feature an antipronation design to minimize the risk of injury from overuse.