Cross-education by Unilateral Resistance Training Preserves Skeletal Muscle Mass and Strength During Immobilization in Patients Undergoing Clavicle Fracture Surgery. A Pilot Randomized Controlled Trial
Cross-education by Unilateral Resistance Training Preserves Skeletal Muscle Mass and Strength During Immobilization in Patients Undergoing Clavicle Fracture Surgery. A Pilot Randomized Controlled Trial
The immobilization process after an operation or injury in the upper extremity causes a loss of muscle mass and strength of 0.2% and 1.3% per day, respectively. Currently, the use of cross-education, which is unilateral training in the uninjured limb, during the immobilization period, is expanding, demonstrating a magnitude of strength gain in the immobilized limb from 8% to 77% of the mean of strength of the trained limb. Despite the evidenced benefits of cross-education in unilateral injuries such as distal radius fracture, anterior cruciate ligament injury, and knee replacement, very little is known about this effect in shoulder immobilization after clavicle fracture.
Objective: : To determine the effects of unilateral resistance exercise training of the uninjured limb on skeletal muscle mass, strength, pain, and disability in the immobilized limb after immobilization (4 weeks) and after standard physiotherapy (8 weeks) in patients undergoing clavicle fracture surgery.
Methodology: Nineteen men (27 ± 5 years) were randomly to a control group (n = 8; immobilization + standard physiotherapy) or experimental group (n = 11; immobilization + unilateral resistance training of the uninjured limb + standard physiotherapy). Outcomes included biceps brachii muscle thickness (ultrasonography), elbow flexion strength (1RM estimate), disability (Quick Dash questionnaire) and pain (visual analog scale), assessed at 4- and 8-week post-clavicle surgery.
Expected results: It is expected to observe a gain in muscle mass and strength in the trained limb and a maintenance/gain of muscle mass and strength in the group that perform cross-training during the immobilization period.
Inclusion Criteria:
(i) male sex, (ii) age 18-40 years (iii), surgically treated mid-clavicular fracture, (iv) body mass index 18.5-30.0 kg/m2, and (v) physically active status.
The study focused on male participants to minimize variability related to sex-specific neuromuscular and morphological responses
Exclusion Criteria:
(i) previous upper-limb fractures or polytrauma, (ii) surgical delay >12 days, (iii) cardiovascular conditions contraindicating exercise, (iv) uncontrolled comorbidities, (v) neurological injury, (vi) smoking, and (vii) use of nutritional supplements known to affect muscle metabolism (i.e., creatine, leucine, glutamine, casein, whey protein, fatty acids, etc.).
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