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 cmH₂O at rest. By design, AB increased Pga,ee by 6.6 ± 0.6 cmH₂O 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.

Keywords: abdominal binding; breathlessness; diaphragm; exercise; neuromuscular efficiency.

Figure 1

Effect of abdominal binding (AB) vs. control (CTRL) on (A) the rate of oxygen consumption ($\dot{\text{V}}$ O₂), (B) cardiac output (C) heart rate, (D) stroke volume, (E) breathlessness, and (F) leg discomfort responses during constant-load cycle endurance exercise testing at 85% of peak incremental power output in healthy men. Values are means ± SEM.

Figure 2

Effect of abdominal binding (AB) vs. control (CTRL) on (A) ventilation, (B) inspiratory capacity, (C) tidal volume, (D) inspiratory reserve volume, (E) respiratory frequency, and (F) peak expiratory flow vs. peak tidal expiratory esophageal pressure (Pes) responses during constant-load cycle endurance exercise testing at 85% of peak incremental power output in healthy men. Values are means ± SEM.

Figure 3

Effect of abdominal binding (AB) vs. control (CTRL) on (A) root mean square of the crural diaphragm electromyogram (EMGdi,rms), (B) transdiaphragmatic pressure (Pdi), (C) esophageal pressure (Pes), (D) Pdi vs. EMGdi,rms, (E) gastric pressure (Pga), and (F) tidal Pdi swing-to-EMGdi,rms ratio responses during constant-load cycle endurance exercise testing at 85% of peak incremental power output in healthy men. Values are means ± SEM. ^*p < 0.05 vs. CTRL. Dashed lines denote expiratory Pdi, Pes and Pga.