Combined effects of muscle fatigue and decision making on knee joint biomechanics

In order to investigate the combined effects of lower limb muscle fatigue and decision making to the knee joint on the people who were classified to possess low or high position-sense-acuity, a controlled laboratory experiment was conducted by recruiting 14 volunteered healthy collegiate males with their anthropometric statistics (denoted in the form of mean value ± standard deviation) including age (23.786 ±1.424), body mass (68.86 ±9.69 kg) and stature (175.79 ± 6.97 cm), respectively. During the jumping followed by cutting maneuver under four simulated cases (i.e. pre-fatigue anticipated, pre-fatigue unanticipated, post-fatigue anticipated, and post-fatigue unanticipated), a motion capture system comprised by eight high-speed (200 fps) cameras was used to collect the three-dimensional coordinates of 18 reflective skin markers, which were attached to those interested positions prior to the experiment. Besides, two force plates were also selected to record the ground-reaction force when the subject landing on the track. Subsequently, a 23 ANOVA analysis was performed after computing all the collected data by means of inverse dynamic approach. Significant increase of knee extension, valgus, and internal rotation moment as well as peak proximal tibial anterior shear force were observed after being induced with fatigue protocol. However, only increased knee extension moment and peak proximal tibial anterior shear force were found when the task was activating by unanticipated stimulus. Knee extension and internal rotation moment together with tibial anterior shear force were significantly magnified under post-fatigue unanticipated condition.Master of Science (Smart Product Design