The effects of a high-intensity exercise bout on landing biomechanics post anterior cruciate ligament reconstruction: a quasi-experimental study

Neuromuscular activity of the lower-extremities during running, landing and changing-of-direction movements in individuals with anterior cruciate ligament reconstruction: a review of electromyographic studies

PURPOSE

Running, jumping/landing and cutting/change of direction (CoD) are critical components of return to sport (RTS) following anterior cruciate ligament reconstruction (ACLR), however the electromyographic (EMG) activity patterns of the operated leg during the execution of these tasks are not clear.

METHODS

A systematic review was conducted to retrieve EMG studies during running, jumping/landing and cutting/(CoD) in ACLR patients. MEDLINE, PubMed, SPORTDiscus and Web of Science databases were searched from 2000 to May, 2022 using a combination of keywords and their variations: "anterior cruciate ligament reconstruction" OR "ACLR", "electromyography" OR "EMG", "running", "jumping" OR "landing", "cutting" OR "change-of-direction" OR "CoD". The search identified studies comparing EMG data during running, landing and cutting/(CoD) between the involved limb and contralateral or control limbs. Risk of bias was assessed and quantitative analyses using effect sizes were performed.

RESULTS

Thirty two studies met the inclusion criteria. Seventy five percent (24/32) of the studies reported altered EMG activity pattern of the ACLR leg during running, jumping/landing and cutting/(CoD) when compared with either the healthy control leg or the contra-lateral leg. Twelve studies showed decreased, delayed or earlier onset and delayed peak in quadriceps EMG activity with small to large effect sizes and 9 studies showed increased, delayed or earlier onset and delayed peak in hamstrings EMG activity with small to large effect sizes. Four studies showed a "hamstrings-dominant" strategy i.e. decreased quadriceps coupled with increased hamstrings EMG activity in both running and jumping/landing irrespective of graft type. One study reported that on the grounds of decreased quadriceps activity, lower hamstrings EMG activity was predictive of ipsilateral re-injury in ACLR patients.

CONCLUSION

This systematic review of Level III evidence showed that the ACLR leg displays decreased quadriceps or increased hamstrings EMG activity or both despite RTS. Simultaneous decreased quadriceps and increased hamstrings EMG activity was shown for both running and jumping/landing. From a clinical perspective this "hamstrings dominant" strategy can serve as a protective mechanism against graft re-injury.

LEVEL OF EVIDENCE

III.

INJURIES IN AEROBIC EXERCISE: CAUSES AND PREVENTIONS

ABSTRACT Introduction: Professional aerobic exercises require high performance from exercisers. Injuries are common during their execution. Understanding the causal reasons is essential for prevention methods to reduce athletes’ injuries. Objective: Investigate the influential factors of ligament injuries caused by aerobic exercise. Methods: This paper analyzes the injuries caused by aerobic exercise through mathematical statistics. Time, course, degree of injury, location of the injury, cause, early treatment time, primary approach, treatment methods, recovery conditions, and speed in recovery time of sports injuries were investigated. Results: Injuries are mainly concentrated at the hip, knee, and ankle joint level; sprains are the first injuries, followed by muscle strains, lower back muscle contractures, kneecap deformities, and joint ligament injuries. The leading causes of injuries were poor warm-up, excessive load, technical errors, and fatigue. Conclusion: Various physiotherapy methods can improve the recovery rate from ligament injuries. This method can also improve sports ligament injuries’ prevention and treatment effects. Evidence Level II; Therapeutic Studies - Investigating the result.