Use of fiber optic goniometer to objectively assess the angle and reflex time of knee jerk in professional rugby players

Abstract

BACKGROUND: Rugby, being a contact and collision game, results in sudden application of forces on lower limb muscles which may injure them unless an immediate reflex contraction of the muscle occurs. This study aimed to assess the knee jerk reflex parameters of professional rugby players. METHODS: Knee jerk parameters (latency, peak time, total duration, relaxation time and angle) of rugby players were assessed. The angle was measured by a bipolar joint angle sensor in the fiber optic goniometer. An electronic tendon hammer was used to elicit the knee jerk. These instruments were connected to a data acquisition hardware and data were recorded on LabChart 8 software (AD Instruments,Sydney,Australia).RESULTS: Mean (SD) of age, height, weight and BMI were 27.4 (3.9) years, 1.72 (0.07) m, 83.4 (14) kg and 27.8 (4.3), respectively (N.=59). There is no correlation between BMI and reflex parameters (P>0.05 for all parameters). Knee jerk parameters from left and right sides did not show a statistically significant difference (P>0.05). Similarly, there was no statistically significant difference between the dominant and non-dominant sides. Individual parameters measured in right side showed a significant correlation (P<0.01) to their counterparts from the left. Latency showed a negative correlation with other parameters from the same leg while other parameters showed a positive correlation between each other. CONCLUSIONS: A fiber optic electronic goniometer and an electronic tendon hammer along with data acquisition hardware and software can be used to objectively measure knee jerk parameters of rugby players.