Effects of Blood Flow Restriction Training and Instrument-Assisted Soft Tissue Mobilization for Pain, Strength, Range of Motion, and Kinesiophobia Among ACL Reconstruction Patients.

Anterior cruciate ligament reconstruction (ACLR) is a commonly performed surgical procedure to restore knee stability following ACL injury. Despite surgical success, many patients experience persistent quadriceps weakness, pain, reduced range of motion (ROM), and psychological barriers such as kinesiophobia, which can delay functional recovery and return to activity. Optimizing early rehabilitation strategies is therefore essential to improve both physical and psychological outcomes after ACLR. Blood Flow Restriction Training (BFR) and Instrument-Assisted Soft Tissue Mobilization (IASTM) are two emerging rehabilitation techniques increasingly used in musculoskeletal and postoperative care. BFR involves the application of controlled external pressure to partially restrict blood flow during low-load resistance exercise, thereby promoting muscle strength and hypertrophy with minimal mechanical stress. This makes it particularly suitable during early rehabilitation phases when high-load exercises may be contraindicated. IASTM is a manual therapy technique that utilizes specialized instruments to mobilize soft tissues, improve circulation, reduce pain, and enhance tissue extensibility. It is commonly used to address soft tissue restrictions, improve joint mobility, and support functional recovery. Although both interventions have demonstrated beneficial effects independently, there is limited comparative evidence evaluating their relative effectiveness in patients undergoing ACLR. Additionally, most previous studies have focused primarily on physical outcomes such as strength and ROM, with limited attention to psychological factors such as kinesiophobia, which play a critical role in rehabilitation success and return-to-sport readiness. This study is designed as a two-arm parallel-group randomized clinical trial to compare the effects of BFR and IASTM on pain, quadriceps strength, knee ROM, and kinesiophobia in patients following ACLR. A total of 46 participants, 8-16 weeks post-surgery, will be recruited and randomly allocated into either the BFR group or the IASTM group using a computer-generated randomization method with allocation concealment. Participants in both groups will receive interventions twice weekly for 8 weeks, in addition to standard postoperative physiotherapy. The BFR group will perform low-load quadriceps strengthening exercises under individualized occlusion pressure, while the IASTM group will receive structured soft tissue mobilization using specialized tools along with conventional rehabilitation exercises. Outcome measures will include quadriceps muscle strength assessed using a handheld dynamometer, pain intensity measured with the Numeric Pain Rating Scale (NPRS), knee ROM assessed using a goniometer, and kinesiophobia evaluated using the Tampa Scale of Kinesiophobia (TSK-17). Assessments will be conducted at baseline and after completion of the intervention period by blinded outcome assessors. The findings of this study will provide comparative evidence regarding the effectiveness of BFR and IASTM in improving both physical and psychological outcomes during early rehabilitation after ACLR. This may assist clinicians in selecting the most appropriate adjunctive treatment to optimize recovery and enhance return-to-function in this patient population.

• Blood Flow Restriction Training (Other): Participants will receive Blood Flow Restriction Training as an adjunct to standard postoperative physiotherapy following ACL reconstruction. A pneumatic cuff will be applied to the proximal thigh at individualized occlusion pressure to allow low-load exercise under restricted blood flow conditions. The exercise program will include straight leg raises, quadriceps sets, and seated/short-arc knee extensions. Training will focus on low-load quadriceps strengthening to promote muscle activation and recovery. The intervention will be performed twice weekly for 8 weeks under physiotherapist supervision. Safety, pain response, and limb tolerance will be continuously monitored during all sessions.
• Instrument-Assisted Soft Tissue Mobilization (IASTM) (Other): Participants will receive Instrument-Assisted Soft Tissue Mobilization as an adjunct to standard postoperative physiotherapy following ACL reconstruction. Specialized stainless-steel instruments will be used to apply controlled mechanical pressure to soft tissues around the knee region. Treatment will target peri-patellar structures, quadriceps, hamstrings, and surrounding thigh musculature. The intervention aims to improve tissue mobility, reduce pain, and enhance range of motion. Sessions will be conducted twice weekly for 8 weeks under trained physiotherapist supervision. Each session will be standardized with continuous monitoring of pain response and treatment tolerance.

Primary outcomes

• Quadriceps Muscle Strength [Baseline and 8 weeks post-intervention]: Quadriceps strength will be assessed using a handheld dynamometer to measure maximal isometric knee extensor force in a standardized seated position. The highest value from repeated trials will be recorded for analysis.
• Pain Intensity [Baseline and 8 weeks post-intervention]: Pain will be assessed using the Numeric Pain Rating Scale (NPRS), where participants rate their knee pain on an 11-point scale from 0 (no pain) to 10 (worst possible pain).

Sex: All, ages: 18 Years to 40 Years

Inclusion Criteria:

* Age between 18 and 40 years.
* Both genders.
* Undergoing Primary Unilateral ACLR (using autologous tendon graft).
* Medically cleared for low load rehabilitation (Wound healed, stable graft per surgeon).
* Active knee flexion of ≥100° on the operative limb.
* 8-16 weeks after reconstructive surgery.
* Willing to comply with all rehabilitation sessions and follow up assessments; give informed consent

Exclusion Criteria:

* Significant meniscectomy requiring protected weight-bearing
* Active DVT, vascular disease, uncontrolled hypertension or other BFR contraindications
* Patients exhibiting extension lag (inability to achieve full active knee extension) on the operated limb.
* Neuromuscular disorders
* Skin lesions preventing IASTM
* Pregnancy
* Contraindications to exercise

• Dr Shaoib Waqas, Phd, Study director, Lahore University of Biological and Applied Sciences