Expiratory muscle strength training and detraining: Effects on speech and cough prediction

Reduced expiratory muscle strength compromises the necessary lung pressure for tasks such as speech and cough. It is known that expiratory muscle strength can be increased with strength training programs. However, there is limited research on the rate and magnitude of expiratory muscle strength increase, the physiologic changes in speech and cough following training, and alterations to these physiologic changes as a function of detraining.; Participants included 32 (20 females; 12 males) healthy individuals with an average age of 25.2 years. A multivariate repeated measures design was used in which measures of expiratory muscle strength, speech, and cough were obtained each week during an expiratory muscle strength training (EMST) program. The participants were divided into two training groups. Group I trained for four weeks. Group II trained for eight weeks. Maximum expiratory pressure (MEP) was used as the measure of maximum expiratory muscles strength. Speech measures were the ratio of subglottal pressure (P_s) to MEP and intraoral pressure (P₀) to MEP, maximum P_s, and peak root mean square. Cough measures were maximum flow rate, compression time, and rise time. All measures were also obtained during an eight-week detraining period to document the rate and magnitude of the strength decrease as well as the loss of physiologic changes in speech and cough.; The results demonstrated a significant increase in MEP in both Group I and Group II, p < .05. A plateau in strength increase was found following the sixth week of training and stayed constant up until the eighth week of training. A significant decrease in P_s/MEP occurred in Group I, p < .05, but not in Group II. A significant decrease in P₀/MEP was found in both Group I and II, p < .05. No significant alterations in cough were noted with training except for a significant decrease in compression time in Group II, p < .05. MEP remained significantly above baseline at eight weeks post-training for both Group I and II, p < .05. These groups did not significantly differ in detraining rates. The results further indicate that investigation of EMST may be of interest in clinical populations which present with expiratory muscle weakness.