Muscle Vibration and Joint Position Sense

The present study aimed to investigate and compare the acute effect of local vibration (63 Hz vs 42 Hz frequencies) on the biceps brachii muscles on the elbow joint position sense (JPS) in healthy young men. Forty-five healthy young men aged 19 to 30 years were enrolled in the study. The participants were randomly assigned to receive either 63 Hz (n=15) or 42 Hz (n=15) or sham vibration (control group) (n=15). Participants in the experimental group received five bouts of 1-minute of each vibration exposure localized to the biceps brachii muscle, with a 1-minute rest between the bouts. Active elbow joint position error (in degrees) was selected as an outcome measure to assess elbow JPS. To measure active elbow joint position error, the subject was made to sit on the chair with eyes closed and shoulders in 0 degree of abduction and elbows fully extended. The examiner passively moved the elbow to 90 degrees of flexion (target position) and maintained it for 10 seconds. The subject was requested to memorize the target position. The subject was asked to actively flex the elbow to the target position from the initial starting position (elbow fully extended) and hold it for 5 seconds. Three trials were conducted, with a 30-second rest given between each trial. The target and reproduced angles in each trial were measured using a standard plastic goniometer. The difference between the target and reproduced angles in each trial was calculated to determine active elbow joint position error. Measurements were taken at baseline and immediately after the vibration protocol.