Prolonged Achilles Tendon Vibration Does Not Alter the Neuromuscular Performance of Plantar Flexor Muscles.

CONTEXT: The prolonged tendon vibration may induce muscle fatigue, as assessed by a decrease in maximal force production. It remains however unknown whether the decrease in muscle strength after prolonged Achilles tendon vibration is related to the vibration frequency.

OBJECTIVE: This study aimed to assess the maximal capacity of plantar flexor neuromuscular function before and after prolonged Achilles tendon vibration at low and high frequencies generated using a portable device.

DESIGN: Pre- and post-test intervention with control.

SETTING: University laboratory.

PARTICIPANTS: Ten healthy males (age 22.6 ± 4.0 yrs).

INTERVENTION: Each subject participated in three experimental sessions that were randomly distributed and separated by one week. During each experimental session, one of the following vibration protocols was applied for 30 minutes: i) 40 Hz vibration, ii) 100 Hz vibration, or iii) no vibration (control protocol).

MAIN OUTCOME MEASURES: MVC torque, voluntary activation level, twitch torque, maximal electromyographic activity, and maximal M-wave of plantar flexor muscles (measured before and after each vibration or control protocol).

RESULTS: Statistical analysis exhibited no significant effect of vibration protocol on the measured variables.

CONCLUSIONS: The current study demonstrates that 30 min of Achilles tendon vibration at a low or high frequency using a portable stimulator did not affect the neuromuscular performance of the plantar flexor muscles. These results emphasize the limits of tendon vibration, whatever the frequency applied, for inducing neuromuscular fatigue.