Introduction. Anterior cruciate ligament repair (ACLR) is becoming increasingly common in Australia. Strength and functional deficits commonly persist beyond a person’s return to sport following an ACLR, and reinjury rates are high. Resistance training (RT) is considered a key component to an ACLR rehabilitation protocol. Furthermore, RT intensity is a crucial variable determining the physiological response of the neuromuscular system. Currently the optimal prescription of RT intensity following ACLR is unknown, and there is no universally accepted best-practice approach to prescribing an RT program following ACLR.

Objective. This systematic review aimed to identify, critique and synthesise the findings of research that has evaluated the effectiveness of RT programs on physical return to sport outcome measures. This review will present the quality of the identified literature, the alignment of current ACLR RT protocols with recommended RT guidelines and the sufficiency of current RT protocols to achieve return to sport criteria and address post-ACLR deficits.

Methods. A comprehensive search of electronic databases (EBSCO health databases [CINAHL, MEDLINE, SPORTDiscus], Scopus and Pedro) was performed and identified studies relevant to the objective. A quality critique of the selected studies was undertaken using a modified Downs and Black appraisal tool. Data central to the study objective were extracted and presented.

Results. In total 10 articles were retained for final review, five of which were categorised as excellent or good quality. Study quality ranged from excellent to poor. RT intensity varied greatly among studies (between 5% and >80% of 1RM). Only one identified study specifically investigated the effect of a low versus high intensity RT protocol. One study investigated the effects of a rehabilitation protocol from time of surgery to beyond six months post-surgery. The majority of studies reported objective data relating to strength and function that would not pass recommended return to sport thresholds.

Conclusion: RT intensity reported in ACLR rehabilitation literature varies considerably. Furthermore, there appears to be no consensus regarding optimal RT intensity following ACLR. Most RT protocols promoted muscle endurance and hypertrophy. Best-practice guidelines informed by high quality evidence are needed to optimise function and minimise risk of reinjury following ACLR.