Immediate effect of vibratory stimuli on quadriceps function in healthy adults
Pamukoff DN, Pietrosimone B, Lewek MD, Ryan ED, Weinhold PS, Lee DR, & Blackburn T. Muscle & Nerve. Published Online First: February 13, 2016; DOI: 10.1002/mus.25081
Take Home Message: Local or whole body vibration treatments increase quadriceps function similarly. Vibration therapy can be a tool to facilitate strengthening protocols.
Vibration techniques (local and whole body) increase quadriceps function immediately after application. However, it is unclear how long these improvements last among healthy individuals. It would be ideal if these benefits lasted long enough to allow someone to complete an exercise program. The authors of this study compared the effects of whole body and local muscle vibration on quadriceps function in healthy individuals and assessed how long changes would persist. The authors recruited 60 healthy and recreationally active individuals. Baseline measures included peak torque, maximal voluntary isometric contraction, central activation ratio, corticomotor excitability, and spinal motorneuron excitability. The authors randomized the 60 participants to whole body vibration, local muscle vibration, or a control intervention group. Both vibration groups received similar bouts of vibration therapy with their knee flexed to about 60 degrees. The local vibration was applied on the quadriceps tendon. The control group stood on the whole body vibration platform but received no vibration. To collect all of these measurements, the participants attended 3 sessions, which were 1 week apart. The authors randomized the type of measurements collected in each session. Baseline measures were reassessed immediately post-intervention, and at 10 and 20 minutes post-intervention. Immediately post-intervention, participants who received whole body vibration had increased peak torque and central activation ratios. Furthermore, both vibration groups had greater EMG increases immediately vibration groups compared with the control group. Corticomotor excitability was enhanced immediately post whole body vibration and persisted up to 20 minutes post intervention; however, these post-intervention measures were not different than the control group. Among participants who received local vibration, a similar pattern was found for one measurement of corticomotor excitability (active motor threshold). There were no differences between whole body and local muscle vibration.
Whole body and local muscle vibration increased quadriceps function in a healthy population, and some of these changes may persist as far as 20 minutes post-treatment – although these extended benefits were not different than the control group. The benefits may be related to changes in corticomotor excitability instead of spinal motorneuron excitability. It would be interesting to see if treatment duration effects how long the improvements persist. Clinicians can incorporate vibration therapy to enhance strengthening during rehabilitation or training. The convenient findings about this study are that there were no differences between the local muscle and whole body vibration groups. Oftentimes whole body vibration units are expensive; hence, local muscle vibration may provide a more cost-feasible option. It would be interesting to see if the findings would be similar in individuals who have suffered a knee injury and have diminished quadriceps function. Vibration therapy is an option that clinicians should remember when looking to improve quadriceps function to assist in strengthening.
Questions for Discussion: Are you currently using any type of vibration therapy as a complement to your treatment or strengthening protocol? What are other options that you have utilized to assist in facilitating quadriceps activation?
Written by: Nicole Cattano
Reviewed by: Jeffrey Driban