Whole-Body Vibration on Performance of Quadriceps After ACL Reconstruction: A Blinded Randomized Controlled Trial

2019 ◽  
Vol 28 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Karinna Sonálya Aires da Costa ◽  
Daniel Tezoni Borges ◽  
Liane de Brito Macedo ◽  
Caio Alano de Almeida Lins ◽  
Jamilson Simões Brasileiro

Context: Whole-body vibration (WBV) has been widely used in clinical and sport practice. These devices produce constant vibrations, originating symmetrical waves that move along the vertical axis. It is suggested that mechanical stimuli produced by high vibration can be an alternative to improve neuromuscular performance and balance in different populations. However, there is still a lack of consensus in the literature regarding neurophysiological responses in the skeletal muscle immediately after the use of WBV, specifically in individuals subjected to anterior cruciate ligament reconstruction. Objective: To investigate the immediate effects of WBV on neuromuscular performance of the quadriceps femoris and postural oscillation of individuals subjected to anterior cruciate ligament reconstruction. Design: This is a blinded randomized controlled trial. Setting: University laboratory. Participants: Forty-four men. Intervention: Participants were randomized into 2 groups: control group (n = 22, exercise protocol on the vibrating platform turned off) and WBV group (n = 22, exercises on the vibrating platform turned on, at a frequency of 50 Hz and amplitude of 4 mm). Main Outcome Measures: The volunteers underwent a dynamometric evaluation of the quadriceps femoris and electromyographic activity of vastus lateralis and vastus medialis muscles, in addition to oscillation of the center of pressure at 2 different moments: before and immediately after the intervention protocol. Results: The intragroup comparison evidenced differences between preassessments and postassessments for the variables of laterolateral amplitude, peak torque, and total work. However, no significant difference was observed in the intergroup comparison after WBV protocol. Conclusion: The use of WBV did not immediately alter the performance of the quadriceps femoris and the electromyographic activity of vastus lateralis and vastus medialis muscles. In addition, it also did not interfere with pressure center oscillation of individuals subjected to anterior cruciate ligament reconstruction.

2020 ◽  
pp. 1-6
Author(s):  
Steven M. Davi ◽  
Colleen K. Woxholdt ◽  
Justin L. Rush ◽  
Adam S. Lepley ◽  
Lindsey K. Lepley

Context: Traditionally, quadriceps activation failure after anterior cruciate ligament reconstruction (ACLR) is estimated using discrete isometric torque values, providing only a snapshot of neuromuscular function. Sample entropy (SampEn) is a mathematical technique that can measure neurologic complexity during the entirety of contraction, elucidating qualities of neuromuscular control not previously captured. Objective: To apply SampEn analyses to quadriceps electromyographic activity in order to more comprehensively characterize neuromuscular deficits after ACLR. Design: Cross-sectional. Setting: Laboratory. Participants: ACLR: n = 18; controls: n = 24. Interventions: All participants underwent synchronized unilateral quadriceps isometric strength, activation, and electromyography testing during a superimposed electrical stimulus. Main Outcome Measures: Group differences in strength, activation, and SampEn were evaluated with t tests. Associations between SampEn and quadriceps function were evaluated with Pearson product–moment correlations and hierarchical linear regressions. Results: Vastus medialis SampEn was significantly reduced after ACLR compared with controls (P = .032). Vastus medialis and vastus lateralis SampEn predicted significant variance in activation after ACLR (r2 = .444; P = .003). Conclusions: Loss of neurologic complexity correlates with worse activation after ACLR, particularly in the vastus medialis. Electromyographic SampEn is capable of detecting underlying patterns of variability that are associated with the loss of complexity between key neurophysiologic events after ACLR.


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