Time course of the effects of vibration on quadriceps function in individuals with anterior cruciate ligament reconstruction

An Acute Bout of Whole-Body Vibration Does Not Improve Jumping Performance in Those With Anterior Cruciate Ligament Reconstruction

CONTEXT

Individuals with anterior cruciate ligament reconstruction (ACLR) often fail to return to their previous level of sport performance. Although multifaceted, this inability to regain preinjury performance may be influenced by impaired plyometric ability attributable to chronic quadriceps dysfunction. Whole-body vibration (WBV) acutely improves quadriceps function and biomechanics after ACLR, but its effects on jumping performance outcomes such as jump height, the reactive strength index (RSI), and knee work and power are unknown.

OBJECTIVE

To evaluate the acute effects of WBV on measures of jumping performance in those with ACLR.

DESIGN

Crossover study design.

SETTING

Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Thirty-six individuals with primary, unilateral ACLR.

INTERVENTION(S)

Participants stood on a WBV platform in a mini-squat position while vibration or no vibration (control) was applied during six 60-second bouts with 2 minutes of rest between bouts.

MAIN OUTCOME MEASURE(S)

Double-leg jumping tasks were completed preintervention and postintervention (WBV or control) and consisted of jumping off a 30-cm box to 2 force plates half the participant's height away. The jumping task required participants to maximally jump vertically upon striking the force plates.

RESULTS

Whole-body vibration did not produce significant improvements in any of the study outcomes (ie, jump height, RSI, and knee work and power) in either limb (P = .053-.839).

CONCLUSIONS

These results suggest that a single bout of WBV is insufficient for improving jumping performance in individuals with ACLR. As such, using WBV to acutely improve jumping performance post-ACLR is likely not warranted. Future research should evaluate the effects of repeated exposure to WBV in combination with other plyometric interventions on jumping performance.

Nurse-Assisted Rehabilitation Protocols Following Anterior Cruciate Ligament Reconstruction

Despite significant advancements in surgical instruments and operation skills, short- and long-term outcomes following anterior cruciate ligament reconstruction (ACLR) remain unsatisfactory, as many patients fail to return to their pre-injury level of sports. Inadequate ACL rehabilitation is the primary cause of poor outcomes. Nurses have become a crucial element in the rehabilitation process. Although there is no consensus regarding the optimal post-operative rehabilitation protocols, restoring muscle strength and neuromuscular control are consistently the primary goals. This literature review presents nurse-assisted rehabilitation protocols aiming at improving muscle strength and neuromuscular control. The review discusses postoperative rehabilitation, including home-based and supervised rehabilitation, open and closed kinetic chain exercises, eccentric and concentric training, blood flow restriction training, and plyometric training. Each training protocol has its benefits and drawbacks, and should be used cautiously in specific stages of rehabilitation. Neuromuscular training, such as neuromuscular electrical stimulation, neuromuscular control exercises, and vibration therapy, is considered crucial in rehabilitation.

Whole-body vibration reduces hamstrings neuromuscular function in uninjured individuals

OBJECTIVES

Despite the growing use of whole-body vibration (WBV) to enhance quadriceps neuromuscular function, the hamstrings-specific response is unclear among those without neuromuscular impairment, which is important to inform performance-based recommendations. Our objective was to determine the immediate and prolonged effects of WBV on hamstrings and quadriceps neuromuscular function in uninjured individuals.

DESIGN

Crossover.

SETTING

Laboratory.

PARTICIPANTS

Nineteen, recreationally active individuals performed WBV and control exercise protocols, consisting of six 1-min repetitions of isometric squats, on separate days in a randomized order.

MAIN OUTCOME MEASURES

Electromyographic (EMG) amplitude, antagonist-to-agonist co-activation, rate of torque development, and peak torque of the hamstrings and quadriceps were measured pre-, immediately post-, and 20 min post-condition. Percentage change scores were calculated from baseline to each post-measurement.

RESULTS

A condition main effect indicated that WBV reduced agonist semitendinosus EMG amplitudes more than the control (-12.1% vs. -1.5%, p < .001). Antagonist vastus medialis EMG amplitudes were reduced immediately, but not 20 min following WBV (-7.1% vs. 3.5%, p < .001).

CONCLUSIONS

WBV induced an inhibitory effect on medial hamstrings activity during knee flexion contraction in a majority of our sample, yet this response was not uniformly observed and its functional relevance remains unclear in an uninjured population.

Neural Correlates of Self-Reported Knee Function in Individuals After Anterior Cruciate Ligament Reconstruction

BACKGROUND

Anterior cruciate ligament (ACL) rupture is a common knee injury among athletes and physically active adults. Despite surgical reconstruction and extensive rehabilitation, reinjuries are common and disability levels are high, even years after therapy and return to activity. Prolonged knee dysfunction may result in part from unresolved neuromuscular deficits of the surrounding joint musculature in response to injury. Indeed, "upstream" neurological adaptations occurring after injury may explain these persistent functional deficits. Despite evidence for injury consequences extending beyond the joint to the nervous system, the link between neurophysiological impairments and patient-reported measures of knee function remains unclear.

HYPOTHESIS

Patterns of brain activation for knee control are related to measures of patient-reported knee function in individuals after ACL reconstruction (ACL-R).

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

In this multicenter, cross-sectional study, participants with unilateral ACL-R (n = 25; 10 men, 15 women) underwent task-based functional magnetic resonance imaging testing. Participants performed repeated cycles of open-chain knee flexion/extension. Neural activation patterns during the movement task were quantified using blood oxygen level-dependent (BOLD) signals. Regions of interest were generated using the Juelich Histological Brain Atlas. Pearson product-moment correlations were used to determine the relationship between mean BOLD signal within each brain region and self-reported knee function level, as measured by the International Knee Documentation Committee index. Partial correlations were also calculated after controlling for time from surgery and sex.

RESULTS

Patient-reported knee function was positively and moderately correlated with the ipsilateral secondary somatosensory cortex (r = 0.57, P = 0.005) and the ipsilateral supplementary motor area (r = 0.51, P = 0.01).

CONCLUSION

Increased ipsilateral secondary sensorimotor cortical activity is related to higher perceived knee function.

CLINICAL RELEVANCE

Central nervous system mechanisms for knee control are related to subjective levels of knee function after ACL-R. Increased neural activity may reflect central neuroplastic strategies to preserve knee functionality after traumatic injury.

Arthrogenic Muscle Inhibition: Best Evidence, Mechanisms, and Theory for Treating the Unseen in Clinical Rehabilitation

CONTEXT

Arthrogenic muscle inhibition (AMI) impedes the recovery of muscle function following joint injury, and in a broader sense, acts as a limiting factor in rehabilitation if left untreated. Despite a call to treat the underlying pathophysiology of muscle dysfunction more than three decades ago, the continued widespread observations of post-traumatic muscular impairments are concerning, and suggest that interventions for AMI are not being successfully integrated into clinical practice.

OBJECTIVES

To highlight the clinical relevance of AMI, provide updated evidence for the use of clinically accessible therapeutic adjuncts to treat AMI, and discuss the known or theoretical mechanisms for these interventions.

EVIDENCE ACQUISITION

PubMed and Web of Science electronic databases were searched for articles that investigated the effectiveness or efficacy of interventions to treat outcomes relevant to AMI.

EVIDENCE SYNTHESIS

122 articles that investigated an intervention used to treat AMI among individuals with pathology or simulated pathology were retrieved from 1986 to 2021. Additional articles among uninjured individuals were considered when discussing mechanisms of effect.

CONCLUSION

AMI contributes to the characteristic muscular impairments observed in patients recovering from joint injuries. If left unresolved, AMI impedes short-term recovery and threatens patients' long-term joint health and well-being. Growing evidence supports the use of neuromodulatory strategies to facilitate muscle recovery over the course of rehabilitation. Interventions should be individualized to meet the needs of the patient through shared clinician-patient decision-making. At a minimum, we propose to keep the treatment approach simple by attempting to resolve inflammation, pain, and effusion early following injury.