Specific inspiratory muscle warm-up enhances badminton footwork performance

The effects of inspiratory muscle (IM) warm-up on IM function and on the maximum distance covered in a subsequent incremental badminton-footwork test (FW_max) were examined. Ten male badminton players were recruited to perform identical tests in three different trials in a random order. The control trial did not involve an IM warm-up, whereas the placebo and experimental trials did involve an IM warm-up consisting of two sets of 30-breath manoeuvres with an inspiratory pressure-threshold load equivalent to 15% (PLA) and 40% (IMW) maximum inspiratory mouth pressure, respectively. In the IMW trial, IM function was improved with 7.8% ± 4.0% and 6.9% ± 3.5% increases from control found in maximal inspiratory pressure at zero flow (P₀) and maximal rate of P₀ development (MRPD), respectively (p < 0.05). FW_max was enhanced 6.8% ± 3.7%, whereas the slope of the linear relationship of the increase in the rating of perceived breathlessness for every minute (RPB/min) was reduced (p < 0.05). Reduction in blood lactate ([La^-]_b) accumulation was observed when the test duration was identical to that of the control trial (P < 0.05). In the PLA trial, no parameter was changed from control. For the changes (Δ) in parameters in IMW (n = 10), negative correlations were found between ΔP₀ and ΔRPB/min (r² = 0.58), ΔMRPD and ΔRPB/min (r² = 0.48), ΔRPB/min, and ΔFW _max (r² = 0.55), but not between Δ[La ^-]_b accumulation and ΔFW_max. Such findings suggest that the IM-specific warm-up improved footwork performance in the subsequent maximum incremental badminton-footwork test. The improved footwork was partly attributable to the reduced breathless sensation resulting from the enhanced IM function, whereas the contribution of the concomitant reduction in [La^-]_b accumulation was relatively minor.