Samenvatting

Introduction: In recent years some researchers investigated the effect of lumbar muscle fatigue on postural control in quiet standing and sitting. The goal of this study was to transfer the question if changes in postural control are visible after fatigue into a functional, dynamic setting.

Research question: Does muscular exhaustion of the back extensor musculature have an effect on dynamic motor control, after a drop jump?

Method: Twenty young healthy students, ten female and ten male, were asked to perform drop jumps from a 25 cm high platform. Ten jumps were recorded in total, five jumps in fatigued and five in an unfatigued state. The intervention exercise consisted of back extensions on a 45° inclined treatment bench until maximal exhaustion was achieved and aimed for at lumbar back extensor muscle fatigue. Each measurement lasted exactly 5 seconds per drop jump, starting with establishing ground contact. Centre of pressure displacement was recorded using a force plate. This output was processed via space time analyses using Codamotion software.

Results: Significant effect was found in anterior-posterior sway after the fatiguing exercise. No effect in medial-lateral sway was observed. Investigating only the first 2,5 seconds separately gives the same result. No significant results were found in anterior-posterior and medial-lateral direction in the last 2,5 second interval.

Conclusion: The findings of this study show a direct relation between lumbar extensor muscle fatigue and postural control in anterior-posterior direction in a dynamic, functional setting. Neuromuscular changes due to fatigue are likely to be the cause for increased sway. Results appear to cohere with previous research assessing sway in static situations.