Optimizing ACL Recovery through Prehabilitation and Blood Flow Restriction Training during Rehabilitation: A Case Study

Article information

Asian J Kinesiol. 2025;27(2):12-18

Publication date (electronic) : 2025 April 30

doi : https://doi.org/10.15758/ajk.2025.27.2.12

Fahmi Abd Rahman¹, Joerg Teichmann¹, Jad Adrian Washif^2,

¹Terramed Physio and Rehab Center Sdn. Bhd., Kuala Lumpur, Malaysia

²Sports Performance Division, Institut Sukan Negara Malaysia (National Sports Institute of Malaysia), Kuala Lumpur, Malaysia

^*Correspondence: Jad Adrian Washif, Sports Performance Division, Institut Sukan Negara (National Sports Institute of Malaysia), KL Sports City, Bukit Jalil, 57000 Kuala Lumpur, Malaysia; Tel: 03-8991-4400; E-mail: jad@isn.gov.my

Received 2024 October 15; Accepted 2025 February 22.

Abstract

Introduction

Anterior cruciate ligament (ACL) injuries are common in sports and remain a concern for healthcare professionals. Treatment options range from conservative rehabilitation exercises, which aim to enhance strength and stability, to surgical interventions for complete ACL ruptures. Surgical repair often addresses knee instability, but post-surgery, patients frequently experience impaired knee strength, functionality, and endurance [1]. Muscle weaknesses, particularly in the quadriceps, are significant barriers to functional recovery after ACL reconstruction (ACLR).

ACL injuries impact strength, proprioception, and gait in both the affected and unaffected limbs, with instability being a primary concern. Prolonged inactivity following an ACL injury can lead to substantial declines in muscular strength, partly due to neural alterations, reducing voluntary activation, a condition known as arthrogenous muscular inhibition (AMI) [2]. This dysfunction may result in abnormal motor patterns, which can hinder daily activities and elevate the risk of re-injury [3]. These factors emphasize the importance of prehabilitation for ACL-injured patients before surgery.

Pre-surgical quadriceps strength is a key predictor of post-surgical knee function [4]. Strengthening muscles and improving movement before surgery are therefore crucial for successful rehabilitation and recovery. Importantly, immobilization, instability, and reduced weight-bearing activities post-injury can lead to muscle weakening and atrophy [5]. Hence, pre-surgical exercise interventions are vital for preparing for surgery and supporting post-surgical rehabilitation to restore knee stability, range of motion, and muscle function for a safe return to sport (RTS).

Prehabilitation has also been shown to enhance post-surgical neuromuscular performance, with significant improvements in quadriceps strength and limb symmetry index (LSI) [1]. Additionally, pre-surgical exercises not only prevent quadriceps weakness but also accelerate strength recovery, aiding rehabilitation and reducing re-injury risk [6].

Blood flow restriction (BFR) therapy is an effective post-ACLR intervention for enhancing muscle strength and function without high load stress. BFR, combined with low-intensity resistance training, promotes muscle adaptations similar to high-intensity training, supporting recovery and functional abilities [7]. BFR facilitates muscle recruitment and hypertrophy, even in patients who are unable to tolerate high loads, offering a promising strategy for post-ACLR rehabilitation.

This case study explores the effects of different pre-surgical rehabilitation approaches on neuromuscular outcomes in individuals from different demographics, and investigates how post-surgical BFR influences the RTS process following ACLR.

Case Presentation

We investigated two distinct male subjects with Grade 3 ACL injuries to assess how age, fitness, and prehabilitation duration influence neuromuscular outcomes and BFR training efficacy post-surgery. Subject 1, a 56-year-old active male, had his ACLR surgery delayed by five months due to an underlying medical condition that necessitated postponement rather than a deliberate choice to pursue conservative treatment alone. He completed a 12-week home-based prehabilitation program focusing on mobility, muscle mass, and neuromuscular stability. Subject 2, a 31-year-old professional footballer, followed a similar prehabilitation program before undergoing ACLR <Table 1>. Post-surgical, both patients underwent six weeks of rehabilitation, incorporating BFR training. Both subjects signed informed consent forms for all procedures and publication, and all procedures adhered to ethical standards and the Declaration of Helsinki.

Table 1.

Prehabilitation programs for the first and second phases.

Intervention

Prehabilitation before surgery. The 12-week program (6 weeks for Subject 2), adapted from Cunba and Solomon [10], was divided into two phases (each lasting 6 or 3 weeks) and involved progressive exercises targeting mobility, strength, and neuromuscular control, advancing up to surgery <Table 1>. Weekly physiotherapy supervision ensured adherence and progression.

Post-surgical rehabilitation. A criterion-based, standardized post-surgical program focused on restoring muscle function and range of motion. The initial phases included passive BFR to prevent atrophy, followed by BFR combined with isometric contractions and neuromuscular electrical stimulation to enhance muscle strength <Table 2>. In our study, BFR was applied via an 8-cm pneumatic cuff (H Cuff 2.0) placed around the upper thigh (below the inguinal crease), to effectively restrict arterial inflow to the quadriceps while ensuring patient safety and comfort, in line with established protocols [11]. As recovery progressed, low-load resistance training was introduced [11]. Rehabilitation continued with conventional training to enhance knee stability and strength, guided by clinical criteria to monitor progression and readiness for RTS <Table 2>.

Table 2.

Program variables for each phase of the 6-week rehabilitation period (3 sequential phases, 2 weeks per phase).

Results

Subject 1 underwent a 12-week prehabilitation, with 3 sessions per week (36 sessions in total), followed by a 6-week post-surgical rehabilitation with application of BFR, also with 3 weekly sessions (18 total sessions). Subject 2 completed a 6-week prehabilitation, with 3 weekly sessions (18 sessions in total), and then proceeded to a 6-week post-surgery rehabilitation incorporating BFR training for 18 sessions (3 sessions per week). The results of isometric leg press for Subjects 1 and 2 are shown in <Table 3>. The results of Y balance test for Subjects 1 and 2 are shown in <Figure 1>. The results of single leg hop test and single leg drop jump for Subject 2 are shown in Table 4 and 5, respectively.

Table 3.

Isometric leg press.

Figure 1.

Results of Y balance test for Subject 1 (A) and Subject 2 (B).

Table 4.

Post-surgical test of single leg hop for Subject 2.

Table 5.

Post-surgical test of single leg drop jump for Subject 2.

Discussion

Prehabilitation before ACLR aims to preserve functional capacity and support the return to pre-injury levels during post-surgery rehabilitation. In this case study, Subject 1, a 56-year-old male, underwent a 12-week prehabilitation program prior to delayed ACLR. He showed improvements in LSI for leg strength and Y balance. Conversely, Subject 2, a professional footballer, experienced a decline in these metrics after completing a 6-week prehabilitation period. Post-surgery, both subjects completed a 6-week rehabilitation program incorporating BFR training, resulting in substantial improvements in leg strength and balance, achieving an LSI above 90%, meeting RTS criteria. Subject 2 continued to improve over 24 weeks in single-leg hop and drop jump tests, demonstrating the benefits of prehabilitation and rehabilitation in enhancing performance and (possibly) reducing re-injury risk.

Pre-surgical rehabilitation (baseline to pre-surgery). Both subjects followed similar pre-surgical protocols focusing on reducing pain, restoring range of motion, and building strength. Subject 1 showed a 7% improvement in injured leg strength, and altered his LSI slightly from 87% to 88%. He also improved his Y balance LSI from 87% to 93%. In contrast, Subject 2’s leg strength decreased by 42%, dropping his LSI from 97% to 54%. His Y balance LSI also decreased from 98% to 76%. The difference in program duration (12 weeks vs. 6 weeks) likely contributed to these contrasting outcomes. As a high-level athlete, Subject 2 was accustomed to structured high training volume, and the abrupt reduction in physical training may have induced a pronounced detraining effect [12]. The 6-week prehabilitation may have been insufficient to enhance performance or mitigate neuromuscular deficits, with factors such as pain, inflammation, or neuromuscular inhibition prior to surgery potentially contributing to the decline. These findings highlight the need for more personalized prehabilitation programs, especially for high-level athletes prone to rapid deconditioning. It is important that successful prehabilitation can prevent reduced muscle strength and abnormal motor patterns caused by inactivity-related neural changes, which is crucial for reducing the risk of re-injury [2, 3].

Delayed ACL reconstruction. Previous research indicates no significant difference in post-surgical outcomes (complication, functional) between delayed and early ACLR; but delaying surgery can allow for adequate prehabilitation, facilitating functional improvements [13]; e.g., enhanced knee function and psychological factors, and thus, the likelihood of returning to competitive levels. For non-professional athletes like Subject 1, a delay in surgery provided time for prehabilitation, resulting in progressive strength and balance improvements. This approach may be beneficial in identifying individuals who could return to sports without surgery. An individualized approach to surgery timing, considering age, activity level, and pain, is recommended to optimize outcomes [13].

Baseline to post-rehabilitation (12 weeks after Surgery). Both subjects showed significant improvements in strength and balance after surgery. Subject 1 had a 27% increase in injured leg strength and achieved symmetry in leg strength and Y balance. This highlights prehabilitation’s potential to preserve muscle performance [5], facilitating post-surgical recovery [1, 6]. Subject 2, despite initial asymmetry, showed a 43% improvement in strength and a 38% improvement in balance within 12 weeks, with his LSI reaching 97%. These gains suggest the synergistic effects of prehabilitation and BFR training [7], aligning with the literature on BFR’s benefits in post-ACLR rehabilitation [14].

Return to sport. Both subjects exceeded the RTS threshold (LSI ≥ 90%) for strength and balance at 12 weeks post-surgery, though drop jump measures ‘lagged’ slightly. Subject 2 improved his single-leg hop LSI from 90% to nearly 100% by 24 weeks, with a substantial increase in drop jump metrics. Drop jump measures (e.g., RSI) are crucial for identifying neuromuscular and functional deficits [15], and may provide a precise indication of interlimb asymmetries [9] that can persist into the final phase of a return-to-sport protocol [15]. These outcomes indicate favorable intervention effects in enhancing neuromuscular control, and additional exercises targeting reactive capacity may be beneficial [15].

In conclusion, the current study demonstrates the effectiveness of prehabilitation before ACLR and BFR training during post-surgical rehabilitation in enhancing strength and balance, meeting RTS criteria, and potentially reducing re-injury risks. Further research with larger samples is needed to validate these findings and refine clinical protocols.

Article information Continued