The control of respiratory pressures and neuromuscular activation to increase force production in trained martial arts practitioners

Purpose The mechanisms that explain the ability of trained martial arts practitioners to produce and resist greater forces than untrained individuals to aid combat performance are not fully understood. We investigated whether the greater ability of trained martial arts practitioners to produce and resist forces was associated with an enhanced control of respiratory pressures and neuromuscular activation of the respiratory, abdominal, and pelvic floor musculature. Methods Nine trained martial arts practitioners and nine untrained controls were instrumented with skin-surface electromyography (EMG) on the sternocleidomastoid, rectus abdominis, and the group formed by the transverse abdominal and internal oblique muscles (EMG tra/io ). A multipair oesophageal EMG electrode catheter measured gastric ( P g ), transdiaphragmatic ( P di ), and oesophageal ( P e ) pressures and EMG of the crural diaphragm (EMG di ). Participants performed Standing Isometric Unilateral Chest Press (1) and Standing Posture Control (2) tasks. Results The trained group produced higher forces normalised to body mass 2/3 (0.033 ± 0.01 vs. 0.025 ± 0.007 N/kg 2/3 mean force in Task 1), lower P e , and higher P di in both tasks. Additionally, they produced higher P g (73 ± 42 vs. 49 ± 19 cmH 2 O mean P g ) and EMG tra/io in Task 1 and higher EMG di in Task 2. The onset of P g with respect to the onset of force production was earlier, and the relative contributions of P g / P e and P di / P e were higher in the trained group in both tasks. Conclusion Our findings demonstrate that trained martial arts practitioners utilised a greater contribution of abdominal and diaphragm musculature to chest wall recruitment and higher P di to produce and resist higher forces.