Contralateral Resistance Training During Immobilization in Patients With Acromioclavicular Joint Injury
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-36
SponsorUniversidad Nacional Andres Bello
About this trial
This randomized controlled trial aims to compare the effects of contralateral eccentric and concentric resistance training performed during the immobilization period following acromioclavicular joint injury. Immobilization is commonly prescribed after injury but may lead to reductions in muscle mass, neuromuscular function, force production, and upper-limb functionality.
Contralateral resistance training, also known as cross-education training, involves exercising the non-injured limb to induce beneficial adaptations in the immobilized limb through neural mechanisms. While both eccentric and concentric exercise may produce contralateral effects, their relative effectiveness in a clinical population remains unclear.
Participants with acute acromioclavicular joint injury requiring sling immobilization will be randomly assigned to either a contralateral eccentric training group or a contralateral concentric training group. During immobilization, participants will perform supervised resistance training with the non-injured upper limb. Following immobilization, all participants will receive the same standardized rehabilitation program.
Neuromuscular function, muscle morphology, force production, upper-limb function, and quality of life will be assessed before immobilization, after immobilization, and following rehabilitation. The findings may contribute to the development of more effective rehabilitation strategies for patients recovering from upper-limb injuries requiring temporary immobilization.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Men and women aged 18 to 36 years.
Diagnosis of acute acromioclavicular joint injury confirmed by an orthopedic surgeon.
Physician-prescribed upper-limb immobilization using a sling for approximately 2 to 4 weeks, with or without surgical repair.
Ability to understand study procedures and provide written informed consent.
Disqualifiers
Previous surgery or severe musculoskeletal injury affecting either upper limb within the previous 12 months.
Neurological disorders affecting motor function or neuromuscular performance.
Contraindications to transcranial magnetic stimulation according to established safety guidelines.
Current participation in another clinical trial or structured upper-limb rehabilitation program.
Trial design
Design model
Parallel
Treatments tested in this trial
Contralateral Eccentric Resistance Training
BehavioralSupervised unilateral eccentric elbow flexor training performed with the non-injured limb during sling immobilization (2-4 weeks). Training is performed 3 times/week, 5 sets of 8-12 repetitions at 60-90% 1RM, with 4-second contractions and 3-minute rest intervals between sets.
Contralateral Concentric Resistance Training
BehavioralSupervised unilateral concentric elbow flexor training performed with the non-injured limb during sling immobilization (2-4 weeks). Training is performed 3 times/week, 5 sets of 8-12 repetitions at 60-90% 1RM, with 4-second contractions and 3-minute rest intervals between sets.
Treatment groups
16 Participants
are divided into 2 treatment groupsGroup A: Contralateral Eccentric TrainingExperimental treatment 1 intervention
Group B: Contralateral Concentric TrainingActive comparator 1 intervention
Trial outcomes
Primary outcomes
1
Maximal Voluntary Isometric Contraction
Maximal voluntary isometric force of the injured upper limb assessed using a calibrated dynamometer. Force values will be recorded during standardized maximal isometric contractions and used to evaluate changes in muscle performance throughout immobilization and rehabilitation. Unit: Newtons (N)
Time frame
Baseline, post-immobilization (2-4 weeks), and post-rehabilitation (6-8 weeks)2
Rate of Force Development
Rate of force development (RFD) of the injured upper limb assessed during maximal voluntary isometric contractions using a calibrated dynamometer. RFD will be calculated from the force-time curve and used as an indicator of explosive force production and neuromuscular performance. Unit: N·s-¹ (N/s)
Time frame
Baseline, post-immobilization (2-4 weeks), and post-rehabilitation (6-8 weeks)Secondary outcomes
1
Elbow Flexors Voluntary Activation
Voluntary activation of the elbow flexors assessed using the interpolated twitch technique during maximal voluntary isometric contractions. Values will be expressed as a percentage of voluntary neural drive to the muscle. Unit: %
Time frame
Baseline, post-immobilization (2-4 weeks), and post-rehabilitation (6-8 weeks)2
Biceps Brachii Motor Supramaximal Response Amplitude
Peak-to-peak amplitude of the motor supramaximal response (MSUP) evoked by peripheral nerve stimulation during submaximal contractions as an indicator of motor pathway excitability. Unit: mV
Time frame
Baseline, post-immobilization (2-4 weeks), and post-rehabilitation (6-8 weeks)3
Biceps Brachii Motor Evoked Potential Amplitude
Motor evoked potential (MEP) amplitude elicited by transcranial magnetic stimulation and normalized to peripheral responses to assess corticospinal excitability. Unit: mV
Time frame
Baseline, post-immobilization (2-4 weeks), and post-rehabilitation (6-8 weeks)4
Biceps Brachii Silent Period Duration
Duration of the electromyographic silent period following transcranial magnetic stimulation during voluntary contractions as an indicator of cortical inhibition. Unit: ms
Time frame
Baseline, post-immobilization (2-4 weeks), and post-rehabilitation (6-8 weeks)Sponsors and contacts
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Source ClinicalTrials.gov