Inspiratory strengthening effect on resistive load detection and magnitudeestimation

Purpose: This study investigated effects of inspiratory muscle training (IM T) on maximal inspiratory pressure (MIP), magnitude estimation (ME), and lo ad detection (LD) of external resistive loads (DeltaR) in healthy subjects. Methods: Ten adult volunteers IMT trained 5 d(.)wk(-1) for 4 wk. A trainin g set consisted of six inspiratory efforts at 75% of MIF; daily training tr ials consisted of four sets. ME was calculated by linear regression, with a ctual and estimated DeltaR loads plotted on log-log scale. LD was calculate d by determining DeltaR(50)/R-0 fraction. Dependent measures were taken pre - and post-IMT. Results: MIP significantly increased from 87 to 139 cmH(2)O pre- to post-IMT, respectively. ME fur individual loads significantly decr eased post-IMT for all but the highest DeltaR. There was no significant dif ference in LD DeltaR(50)/dR(0) post-IMT. Conclusions: The results demonstra te that inspiratory muscle strength gains were associated with decreased ME of Delta Rs without changing LD DeltaR(50)/R-0. This suggests that the mec hanisms mediating the detection of Delta Rs may be different than the mecha nisms for estimating DeltaR size.