A Biomechanical Analysis Of Punching During Martial Artsinspired Exercise

Abstract

Growth and participation in boxing and martial arts-based exercise classes has occurred. It has been suggested that a risk of injury to the shoulders, elbow, and neck exists due to martial arts-inspired movements. Purpose To examine the effect of external loading (no additional weight (NW), 1-lb and 2-lb weight conditions) and music tempo (125 and 140 beats/min) on kinematic characteristics of selected upper extremity segments and the kinetic characteristics of the glenohumeral joint (GHJ) during the execution of the jab and the hook. Methods Ten certified martial arts exercise instructors were recorded by 6 high-speed video camcorders while performing 20 punches for each movement condition and the 10th punch was analyzed. Graphical procedures, descriptive statistics, and 2 × 3 repeated measures ANOVA were used to describe the kinematic, kinetic, and temporal data with the statistical level for the analysis set at p<0.05. Results The mean peak linear acceleration (56±3 vs. 39±2 for the jab and 50±8 vs. 24±3 m/s2 for the hook, p<0.05) and normalized time-to-peak (NTTP) (40±1 vs. 31±2 for the jab and 55±1 vs. 51±1 % for the hook, p<0.05) decreased as weight increased from NW to a 2-lb weight, whereas linear range of motion decreased (0.34±.03 vs. 0.26±.02 m, p<0.05) for the hook only. As weight increased from the NW to the 2-lb weight condition for both punches, the shoulder NJM increased (11±1 vs. 14±1 for the jab and 15±1 vs. 18±1 Nm/kg for the hook). Conclusion For the jab and hook both weight and tempo changes contribute to changes in linear and angular motion and timing of upper extremity segments, as well as, to changes in kinetic characteristics of the GHJ.