Investigation into intra-abdominal pressure and neuromuscular activation to increase force production in traditional martial arts practitioners

Investigation into intra-abdominal pressure and neuromuscular activation to increase force production in traditional martial arts practitioners

Introduction: The extent to which martial arts practitioners utilise respiratory pressures and neuromuscular activation during force production is not well known. This study investigated whether Chinese wushu (kung fu) practitioners utilise a greater proportion of intra-abdominal pressure (IAP) and neuromuscular activation of the respiratory and pelvic floor muscles to increase their force production compared to healthy control participants.

Methods: Nine trained wushu practitioners and nine healthy untrained control participants were instrumented with skin-surface electromyography (EMG) electrodes on the sternocleidomastoid (EMGscm), rectus abdominis (EMGra) and the group formed by the transverse abdominal and internal oblique muscles (EMGtra/io). A multipair oesophageal EMG electrode catheter measured EMG of the crural diaphragm (EMGdi) along with gastric (Pg: a surrogate measure of IAP), transdiaphragmatic (Pdi), and oesophageal (Pe) pressures. Participants performed two tasks to measure force production: Standing Isometric Push and Standing Isometric Resistance. Participants were familiarised with the tasks and performed a minimum of three efforts for each task. Within-day, between-trial reproducibility intraclass correlation coefficients (ICC) for pressure, force and EMG were > 0.67 for trained and > 0.53 for control participants in the Standing Isometric Push task. ICC were also > 0.86 for trained and > 0.71 for control participants in the Standing Isometric Resistance task.

Results: Compared to the control group, the trained group produced higher levels of force, lower Pe, and higher Pdi in both tasks (P < 0.05). The trained group produced higher Pg and higher EMGtra/io in the Standing Isometric Push task, and higher EMGdi in the Standing Isometric Resistance task (P < 0.05). The trained group had an earlier onset of Pg with respect to the onset of force production than the control group (P < 0.05). The relative contribution of Pg/Pe and Pdi/Pe were higher for the trained group (P < 0.05). Significant positive correlations were found between Pg and absolute force production in both groups (P < 0.05).

Conclusions: Trained wushu practitioners appear to utilise IAP to a greater extent than untrained controls with similar physical activity levels to produce higher levels of force. These findings may have implications in a wide range of sports and activities, as these methods may be adapted and taught to individuals to improve performance, prevent injury or aid in rehabilitation.