By Emily Delzell
Both direct local muscle vibration (LMV) and whole body vibration (WBV) improve quadriceps arthrogenic muscle inhibition (AMI), according to a study from neuromuscular researchers at the University of North Carolina at Chapel Hill. The findings suggest vibratory stimuli can enhance quadriceps strengthening by minimizing AMI, a common complication of knee pathology that can increase the risk of post-traumatic osteoarthritis.
Investigators recruited 43 healthy volunteers and randomized them to WBV, LMV, or control groups. They injected saline into the knees of all participants to induce quadriceps AMI and had participants perform isometric squats while undergoing WBV, LMV, or no intervention. Researchers assessed quadriceps function at baseline, immediately after injection, and immediately and five minutes after intervention.
Central activation ratio (CAR) and voluntary peak torque (VPT) improved immediately after intervention in both test groups, but not in controls. The magnitude of improvement did not differ significantly between the WBV group (CAR, +11.4%; VPT, +16.5%) and the LMV group (CAR, +7.3%; VPT, +23%).
The Archives of Physical Medicine and Rehabilitation epublished the results on July 29.
Blackburn JT, Pamukoff DN, Sakr M, et al. Whole body and local muscle vibration reduce artificially induced quadriceps arthrogenic inhibition. Arch Phys Med Rehabil 2014 Jul 29. [Epub ahead of print]