title: Respiratory motor output during an inspiratory capacity maneuver is preserved despite submaximal exercise.
abstract: It is unknown whether respiratory motor output is constrained during exhaustive exercise in healthy adults. We hypothesised that neural inhibition did occur; to test this hypothesis we measured diaphragm EMG from a maximal inspiratory capacity maneuver (EMG(di)-IC) at rest and during exercise. EMG(di)-IC was measured before and after the amplitude of the diaphragm EMG entered a plateau phase in eleven healthy adults undertaking exercise at 60% and 80% of maximal workload achieved from incremental exercise. The mean EMG(di)-IC at rest was 65 ± 16% of the maximum that could be obtained from a battery of inspiratory tasks. Before and after the plateau phase of diaphragm EMG, EMG(di)-IC was 68 ± 13% and 72 ± 12% (p > 0.05) during 60% of the maximum workload, and was 70 ± 13% and 78 ± 13% (p > 0.05) during 80% of the maximum workload achieved on an incremental test. A further sub-study in which 5 participants exercised at 90% of the maximum workload also showed that EMG(di)-IC was not diminished during exercise. Our data show that exercise condition does not reduce the magnitude of EMG(di)-IC. This argues against neural inhibition as feature of submaximal exercise in healthy adults.
authors.affiliation: Guangzhou Medical College, State Key Laboratory of Respiratory Disease, Guangzhou 510120, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Zhang
authors.forename: Haihong
authors.initials: H
authors.lastname: Gong
authors.forename: Gan
authors.initials: G
authors.lastname: Lu
authors.forename: Hongxi
authors.initials: H
authors.lastname: Guo
authors.forename: Ruifa
authors.initials: R
authors.lastname: Li
authors.forename: Nanshan
authors.initials: N
authors.lastname: Zhong
authors.forename: M I
authors.initials: MI
authors.lastname: Polkey
authors.forename: Yuanming
authors.initials: Y
authors.lastname: Luo
mesh_terms: D000328:Adult; D003964:Diaphragm / Q000294:innervation* / Q000502:physiology*; D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007320:Inspiratory Capacity / Q000502:physiology*; D008297:Male; D012119:Respiration
keywords: Diaphragm; Diaphragmatic electromyography; Exercise testing; Inspiratory capacity