Inspiratory strengthening effect on resistive load detection and magnitude estimation.

Abstract

This study investigated effects of inspiratory muscle training (IMT) on maximal inspiratory pressure (MIP), magnitude estimation (ME), and load detection (LD) of external resistive loads (deltaR) in healthy subjects. Ten adult volunteers IMT trained 5 d x wk(-1) for 4 wk. A training set consisted of six inspiratory efforts at 75% of MIP; daily training trials consisted of four sets. ME was calculated by linear regression, with actual and estimated deltaR loads plotted on log-log scale. LD was calculated by determining deltaR50/Ro fraction. Dependent measures were taken pre- and post-IMT. MIP significantly increased from 87 to 139 cmH2O pre- to post-IMT, respectively. ME for individual loads significantly decreased post-IMT for all but the highest deltaR. There was no significant difference in LD deltaR50/Ro, post-IMT. The results demonstrate that inspiratory muscle strength gains were associated with decreased ME of deltaRs without changing LD deltaR50/Ro. This suggests that the mechanisms mediating the detection of deltaRs may be different than the mechanisms for estimating deltaR size.