Abdominal Binding Improves Neuromuscular Efficiency of the Human Diaphragm during Exercise

Abstract

We tested the hypothesis that elastic binding of the abdomen (AB) would enhance neuromuscular efficiency of the human diaphragm during exercise. Twelve healthy non-obese men aged 24.8 ± 1.7 years (mean ± SE) completed a symptom-limited constant-load cycle endurance exercise test at 85% of their peak incremental power output with diaphragmatic electromyography (EMGdi) and respiratory pressure measurements under two randomly assigned conditions: unbound control (CTRL) and AB sufficient to increase end-expiratory gastric pressure (Pga,ee) by 5-8 cmH 2 O at rest. By design, AB increased Pga,ee by 6.6 ± 0.6 cmH 2 O at rest. Compared to CTRL, AB significantly increased the transdiaphragmatic pressure swing-to-EMGdi ratio by 85-95% during exercise, reflecting enhanced neuromuscular efficiency of the diaphragm. By contrast, AB had no effect on spirometric parameters at rest, exercise endurance time or an effect on cardiac, metabolic, ventilatory, breathing pattern, dynamic operating lung volume, and perceptual responses during exercise. In conclusion, AB was associated with isolated and acute improvements in neuromuscular efficiency of the diaphragm during exercise in healthy men. The implications of our results are that AB may be an effective means of enhancing neuromuscular efficiency of the diaphragm in clinical populations with diaphragmatic weakness/dysfunction.

Effect of Abdominal Binding on Diaphragmatic Neuromuscular Efficiency, Exertional Breathlessness, and Exercise Endurance in Chronic Obstructive Pulmonary Disease

“…The desired degree of abdominal compression – defined as a 5–8 cmH 2 O increase in Pga,ee – was achieved by tightening Velcro fasteners at the front of the binder with participants breathing normally while seated at rest. We recently demonstrated that this level of abdominal compression enhanced diaphragmatic neuromuscular efficiency during exercise in healthy young men, as evidenced by an 85–90% increase in the quotient of Pdi,tidal to EMGdi,rms ( Abdallah et al, 2017 ). Furthermore, West et al (2012) demonstrated that this level of abdominal compression was associated with significantly greater improvements in diaphragm function than increasing Pga,ee by 1.0–3.5 cmH 2 O in healthy adults and people with cervical SCI.…”

“…Constant-load CPETs consisted of a baseline rest period of ≥6-min, followed by 1-min of unloaded pedaling and then a step increase in power output to 75% PPO maintained to symptom-limitation. Cardiac, metabolic, gas exchange, and breathing pattern parameters were collected breath-by-breath and analyzed as previously described ( Abdallah et al, 2017 ). Inspiratory capacity maneuvers were performed at rest, every 2-min during CPET, and at end-exercise ( Guenette et al, 2013 ).…”

“…Published methods were used to analyze breath-by-breath measures of EMGdi,rms and of esophageal (Pes), gastric (Pga) and transdiaphragmatic pressure (Pdi = Pga-Pes) recorded from a gastro-esophageal electrode-balloon catheter (Guangzhou Yinghui Medical Equipment Ltd., Guangzhou, China) ( Jensen et al, 2011 ; Mendonca et al, 2014 ; Abdallah et al, 2017 ). Maximum voluntary EMGdi,rms was identified as the largest of all EMGdi,rms values obtained from IC maneuvers performed either at rest or during exercise.…”

“…We recently demonstrated that increasing Pga,ee by 6.6 ± 0.6 cmH 2 O (mean ± SE) at rest via AB markedly improved diaphragmatic neuromuscular efficiency – quantified as the quotient of tidal transdiaphragmatic pressure swing (Pdi,tidal) to the root mean square of the crural diaphragm electromyogram (EMGdi,rms) – by 85–90% during cycle endurance exercise testing in healthy young men ( Abdallah et al, 2017 ). Despite this improvement, AB had no effect on exertional breathlessness and exercise endurance, likely because diaphragmatic neuromuscular inefficiency is not the proximate source of exertional breathlessness and exercise limitation in healthy young adults ( Abdallah et al, 2017 ).…”

“…We recently demonstrated that increasing Pga,ee by 6.6 ± 0.6 cmH 2 O (mean ± SE) at rest via AB markedly improved diaphragmatic neuromuscular efficiency – quantified as the quotient of tidal transdiaphragmatic pressure swing (Pdi,tidal) to the root mean square of the crural diaphragm electromyogram (EMGdi,rms) – by 85–90% during cycle endurance exercise testing in healthy young men ( Abdallah et al, 2017 ). Despite this improvement, AB had no effect on exertional breathlessness and exercise endurance, likely because diaphragmatic neuromuscular inefficiency is not the proximate source of exertional breathlessness and exercise limitation in healthy young adults ( Abdallah et al, 2017 ). Nevertheless, the collective results of Alexander and Kontz (1934) , Gordon (1934) , Celli et al (1985) , West et al (2012 , 2014 ) and ourselves ( Abdallah et al, 2017 ) provide a physiological rationale for the use of AB as a potentially effective non-pharmacological means of alleviating exertional breathlessness and improving exercise tolerance in adults with COPD by improving dynamic operating lung volumes and/or enhancing diaphragmatic neuromuscular efficiency.…”