Crossed Education in Relation to Muscle Mass in Patients Operated of Clavicular Fracture (crossed1)

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.

Study Overview

• Status: Completed
• Conditions: Clavicle Fracture
• Intervention / Treatment: Other: standard physical therapy; Other: concentric-eccentric strength training

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 19
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Chile
  • IX Región de La Araucanía
    • Temuco, IX Región de La Araucanía, Chile, 4780000
      • Universidad de La Frontera

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

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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Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: standard physical therapy; Men with clavicle fracture immobilized for 4 weeks + standard physical therapy for 8 weeks	Other: standard physical therapy; Following the immobilization, participants initiated a standardized physiotherapy program conducted two to three times per week (9 sessions). All sessions were supervised by a physiotherapist experienced in musculoskeletal rehabilitation.
Experimental: Unilateral Strength Training; Unilateral resistance training was performed on the elbow flexors of the uninjured arm conducted three times per week for 4 weeks (12 sessions), with intensity ranging from 60 to 80 % of one-repetition maximum. Exercises were performed in a seated position with the elbow and forearm supported on a preacher curl bench at 45º of shoulder flexion. Two types of resistance exercise training modalities were included for exploratory purposes	Other: concentric-eccentric strength training; Concentric-eccentric strength cross training in a 8-week immobilization period + 8-week standard kinesic therapy (2 times a week)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in muscle thickness of the biceps brachi muscle by ultrasound.	Biceps brachii muscle thickness was measured using ultrasonography (Sonus SL-5C, Leoni medical, China) by an experienced evaluator blinded to participant allocation. Participants were positioned supine with both arms extended and relaxed. The ultrasound transducer was placed transversely at 60% of the distance between the acromion and the lateral epicondyle of the humerus. Three images were obtained for each measurement using the ImageJ software (v1.54t, Wayne Rasband, USA), in which the average of three different measurements was obtained considering the distance between the superficial muscle fascia and the humerus.	before surgery, after 4 and 8 weeks postoperatively
Elbow's Flexor Muscles Strength	Participant were with the elbow and forearm supported on a preacher curl bench. Elbow flexion strength was assessed an estimated concentric 1-RM (lifting phase) using adjustable dumbbells. A standardized warm-up was performed consisting of 10 repetitions with 1.5 kg load using the uninjured limb. Subsequently, maximal strength was estimated using a submaximal multiple-repetition test, and 1-RM was calculated using the Brzycki formula. 7 The load was progressively, a maximum of 6 attempts was allowed.	Before Surgery, 4 and 8 weeks post surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Upper and middle arm circumference change in both posterior arms	Upper and middle arm circumference change in both posterior arms	before surgery, after 6 and 12 weeks postoperatively
Change in functionality using the Quick Dash questionnaire	Change in functionality using the Quick Dash questionnaire	before surgery, after 6 and 12 weeks postoperatively
Change in relation to pain using the visual analogue scale	Change in relation to pain using the visual analogue scale	before surgery, after 6 and 12 weeks postoperatively

Collaborators and Investigators

• Sponsor: Universidad de La Frontera
• Investigators: Principal Investigator: Gabriel Marzuca, MSc, PhD, Universidad de La Frontera. Temuco, Chile

Study record dates

Study Major Dates

• Study Start (Actual): October 19, 2023
• Primary Completion (Actual): June 25, 2025
• Study Completion (Actual): December 20, 2025

Study Registration Dates

• First Submitted: March 20, 2023
• First Submitted That Met QC Criteria: April 10, 2023
• First Posted (Actual): April 12, 2023

Study Record Updates

• Last Update Posted (Actual): June 4, 2026
• Last Update Submitted That Met QC Criteria: June 2, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: muscle mass; eccentric training; cross education
• Additional Relevant MeSH Terms: Wounds and Injuries; Fractures, Bone
• Other Study ID Numbers: 057/23

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No