Functional Effects of Blood Flow Restriction Training, as Measured by the Starexcursion Balance Test and Weight-Bearing Lunge Test, in Patients Who Have Undergone Anterior Cruciate Ligament Reconstruction Among Ball Players

INTERVENTION: Group 1: Following enrolment and written informed consent, baseline testing (anthropometrics, SEBT, WBLT) is performed at 6 weeks post‐surgery. Participants are then randomly allocated to the intervention or control group. Over 6–8 weeks, both groups complete 14–16 training sessions (2–3 per week) using an identical standardised exercise protocol (cycle ergometer, lateral mini‐band walks, bilateral and single‐leg hip bridges, bo Xsquats to 90°, lunges). The intervention group performs the same protocol under blood flow restriction (10 cm cuff placed proximally on the thigh; individualised pressure set at arterial occlusion pressure determined by Doppler ultrasound over the posterior tibial artery minus 20 %; 60 s of cuff deflation after half of the exercises). The control group trains without a cuff. Identical post‐testing (SEBT, WBLT) is performed at 12–14 weeks post‐surgery. No blinding is applied. Participants: 10 participants (4 women, 6 men) aged 18 to 35 years following a first rupture of the anterior cruciate ligament and surgical reconstruction with a semitendinosus tendon autograft. Before injury, all participants took part two to three times per week in a pivoting ball sport (soccer, volleyball, American football, rugby, basketball, badminton or comparable) in which the injury had occurred. Intervention: From the sixth postoperative week, participants completed a standardised six‐week exercise programme with additional blood flow restriction applied to the operated limb. The programme comprised five minutes of cycle ergometry (100 W, 50–60 rpm), lateral mini‐band walks (4 × 5 m), supine glute bridges with a mini‐band above the knees (3 × 20), single‐leg glute bridges (3 × 10 per side), bo Xsquats to 90° of knee flexion (3 × 10) and forward lunges (2 × 10 per side). For flow restriction, a pneumatic cuff 10 cm wide was applied proximally on the operated thigh. Individual arterial occlusion pressure was determined beforehand using hand‐held Doppler ultrasound by inflating the cuff until the posterior tibial artery signal was extinguished at the level of the Achilles tendon; training pressure was set at 80 % of that value. The resulting mean pressure was 176 ± 15 mmHg (range 160–200 mmHg). The cuff remained inflated for up to ten minutes per block and was deflated once for 60 seconds after the mini‐band walks. Session duration and frequency: Two to three training sessions per week, 16 sessions scheduled in total; a minimum of 12 completed sessions was required for inclusion in the analysis. Each training session lasted approximately [45] minutes including cuff application. In addition, participants attended two measurement sessions (before and after the intervention) of approximately [60] minutes each, and a single determination of arterial occlusion pressure of approximately [15] minutes before the first training session. Observation period: Si Xweeks per participant, from the sixth to the twelfth postoperative week. Overall data collection period: January to July 2021. Outcomes: Dynamic postural co CONDITION: ACL Reconstruction Bloodflow Restriction Training INCLUSION CRITERIA: none PRIMARY OUTCOME: What: Change in the dynamic stance leg stability of the operated leg in the Star Excursion Balance Test (SEBT), measured as reach in cm in eight star‐shaped directions offset by 45°, as well as the symmetry index between the operated and non‐operated legs (target value 1.0 = complete alignment).; ; Outcome measure: A significantly greater improvement (pre‐post difference or convergence of the symmetry index toward 1.0) in the intervention group compared to the control group.; ; When: Two measurement time points—T1 in the 6th postoperative week (before randomization/intervention), T2 in the 12th–14th postoperative week (after 14–16 training sessions).; ; How: Testing on a standardized measurement mat (MAT Assessments) following a standardized procedure: hands on hips, supporting foot remains fully on the ground, contralateral leg taps the ground three times in each direction, and the highest value is recorded; sequence is clockwise, starting with the operated leg. Data recorded on a standardized measurement sheet by the same evaluator.; ; Secondary endpoint: Dorsiflexion of the ankle joint in the Weight‐Bearing Lunge Test (WBLT), measured in degrees using the “Goniometer Pro” app, at identical time points T1 and T2.