Do harder midsoles facilitate propulsion and do softer midsoles increase shock attenuation during taking-off and landing of scissor jump?

To determine the influence of midsole hardness on ground reaction force (GRF) features during badminton scissor jump takeoff and landing and the interactive effect of midsole hardness with playing and nonplaying limbs, data were collected from badminton athletes who performed scissor jumps while wearing shoes with two levels of midsole hardness. Temporal-spatial and GRF variables were calculated. Measurements of the soft and hard midsole conditions for playing versus non-playing sides were compared using two-way repeated measure analyses of variance. The playing and non-playing limbs showed different GRF features while performing scissor jump. During takeoff, no significant differences between the soft and hard midsole conditions were identified for the jump height in any of the GRF variables. During landing, the cushioning capacity might be affected by harder midsole indicated by higher vertical impact peak (p = 0.008). Meanwhile, the longer time-to-vertical impact peak (p = 0.007) and the lower loading rate of the vertical impact peak (p = 0.013) may be plausible indicators for cushioning. Current study indicated the playing-limb consistently showed dominance on both the propulsion and shock attenuation behaviours during scissor jump and that, for the footwear selection between 62C and 68C midsoles, expectation would be more on effects on landing characteristics than on propulsion performance.