Brief Summary Study type: Randomized controlled trial (interventional). Purpose: To find out whether six weeks of unilateral resistance training (URT) improves lower-limb strength and inter-limb symmetry more than traditional bilateral resistance training (BRT) after anterior cruciate ligament reconstruction (ACLR). Main questions: Does URT produce better limb-symmetry in knee flexor/extensor peak torque than BRT? Does URT lead to larger gains in feed-forward motor control, Lysholm knee score and International Knee Documentation Committee 2000 (IKDC 2000) subjective rating? Comparison: Participants will be randomly assigned to URT (each exercise done one leg at a time) or BRT (both legs work together). Training volume, frequency, session length and progression rules are identical in both groups. What participants will do: After giving consent, complete baseline tests of strength, motor control and knee questionnaires. Attend 3 supervised sessions per week for 6 weeks. Each session lasts \~70 min: 5 min warm-up on cycle ergometer 5 min core-stability work 50 min strength circuit (6 exercises, 2 min between sets, 3 min between exercises) 10 min stretching/cool-down One-repetition maximum (1RM) re-tested at week 3 to adjust load. Final assessment within 3 days after the last training session (same tests as baseline).
Detailed Description This single-center, prospective, randomized controlled trial will enroll 48 patients who have undergone primary anterior cruciate ligament reconstruction (ACLR) at Chongli Campus, Peking University Third Hospital. After providing written informed consent, participants will be randomly allocated in a 1:1 ratio to either the unilateral resistance training (URT) group or the bilateral resistance training (BRT) group (24 per group). URT: Each exercise is performed independently with one limb at a time, isolating the target limb while contralateral stabilizers are simultaneously activated to maintain balance. BRT: Both limbs simultaneously move against a shared resistance, keeping the center of gravity stable and the movement symmetrical. Baseline assessments will be completed within one week before the first training session; post-intervention testing will occur within three days after the final session. The program lasts six weeks, with three supervised sessions per week. Every session comprises: 5-min warm-up on a cycle ergometer 5-min core-stability work 50-min strength training (the only component that differs between groups) 10-min stretching and cool-down Six exercises are prescribed in identical order for both groups: towel-squeeze press, seated leg press, knee-extension against resistance, long-lever glute bridge, prone hamstring curl, and Romanian dead-lift. Two minutes of rest are given between sets; three minutes separate exercises. Load is set at 60 % of the relevant one-repetition maximum (1RM), re-tested at baseline and week 3 to allow progression. URT protocol: Each exercise is executed first by the involved leg, then immediately by the uninvolved leg; completion of both sides constitutes one set. The time needed for the uninvolved leg is counted as part of the inter-set interval. BRT protocol: Both legs work simultaneously; 1RM is determined bilaterally. Training volume, frequency, session duration, and progression criteria are therefore identical; only the resistance modality (unilateral vs bilateral) differs. Primary outcomes are limb-symmetry indices for peak torque of knee extensors and flexors (isokinetic dynamometry). Secondary endpoints include feed-forward motor control scores, Lysholm knee scale, and IKDC 2000 subjective evaluation. All measurements are obtained pre-intervention and at week 6. The study will determine whether six weeks of URT confers superior strength recovery and inter-limb symmetry compared with conventional BRT after ACLR.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
48
After signing the informed consent form, the relevant indicators for the pre-trial tests can be conducted.Outcome assessments are conducted at baseline (1 day before the intervention) and 3 days after the final training session (day 45 of the study).The entire trial period lasts for 6 weeks, with 3 training sessions per week. The entire training process includes 5 minutes of warm-up (power bike), 5 minutes of core strength training, 50 minutes of muscle strength training, and 10 minutes of stretching training. The training methods of the two groups are only different in the muscle strength training method. The experimental group (URT group) performs unilateral resistance training for both lower limbs, while the control group (BRT group) performs bilateral resistance training for both lower limbs. There are a total of 6 training actions: towel roll compression training, sitting leg-cranking training, knee extension resistance training, distant hip bridge train
Peking University Third Hospital of Chongli
Zhangjiakou, Hebei, China
muscle strength
Isokinetic muscle strength test Before the test, the participants were instructed on the basic principles of isokinetic strength testing and were required to perform three maximum knee extensions as a warm-up. After the warm-up, the patients rested for 2 minutes, and then performed 5 repetitions at speeds of 60°/s and 180°/s. The peak torque values (PT) of the quadriceps and hamstring muscles of both limbs during the 5 attempts were recorded.
Time frame: Baseline (1 day before the intervention) and 3 days after the final training session (day 45 of the study)
Thigh circumference measurement (unit: cm)
The patient lies on their back, in a relaxed position, with both legs naturally apart. The tape measure is placed 10 cm above the upper edge of the patella and measures the length for one week. (During the measurement, the tape measure should be firmly attached to the skin, not too tight or too loose.) Measurements are taken three times on each side, and the average value is calculated, accurate to one decimal place.
Time frame: Baseline (1 day before the intervention) and 3 days after the final training session (day 45 of the study)
Lysholm knee score scale
Time frame: Baseline (1 day before the intervention) and 3 days after the final training session (day 45 of the study)
Knee joint IKDC 2000 score
Time frame: Baseline (1 day before the intervention) and 3 days after the final training session (day 45 of the study)
Single-leg jump (unit: cm)
Single-leg jump (unit: cm): The patient places both hands behind their back and performs a single-leg jump. Measure three times and take the farthest distance. The patient is instructed to start from the uninjured leg and place their toes behind the marked starting line. Use a standard tape measure to measure the jumping distance from the starting line to the patient's heel. The measurement can be taken only if the patient can remain stable after landing; otherwise, the measurement needs to be redone.
Time frame: Baseline (1 day before the intervention) and 3 days after the final training session (day 45 of the study)
Landing Error Scoring System,LESS
Time frame: Baseline (1 day before the intervention) and 3 days after the final training session (day 45 of the study)
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