Cross-education of Skill and Strength in Healthy People Subjected to an Upper-limb Disuse Model (IMMO-CROSS)

Cross-education of Skill and Strength Through Contralateral Manual Dexterity Training in Healthy Young Adults Subjected to an Upper-limb Disuse Model: A Randomized Controlled Trial.

This randomized controlled trial aims to compare manual dexterity and strength between a group undergoing a contralateral manual dexterity training program and a no-intervention control group in healthy, physically inactive individuals subjected to an induced upper-limb disuse model.

Study Overview

• Status: Not yet recruiting
• Conditions: Immobilization; Disuse Atrophy
• Intervention / Treatment: Other: Contralateral Manual Dexterity Training

Detailed Description

Cross-education of skill offers promising opportunities for the rehabilitation of upper-limb musculoskeletal injuries. An approach based on contralateral manual dexterity training could accelerate functional recovery, reduce motor skill loss during periods of immobilization, and optimize conventional rehabilitation protocols. However, controlled studies are needed to analyze the efficacy of specific unilateral training protocols designed to maximize cross-education before clinical translation. To date, no experimental studies have been published on healthy individuals subjected to upper-limb disuse models alongside contralateral skill training involving functional tasks. This cross-education effect could potentially prevent the loss of manual dexterity and strength that occurs during immobilization. For this research, a contralateral manual dexterity training protocol was developed based on the functional limitations commonly experienced by individuals with forearm and hand musculoskeletal injuries (e.g., distal radius fractures, wrist sprains, carpal tunnel syndrome, and tendinopathies). Additionally, the protocol incorporates characteristics from training programs that have demonstrated the greatest cross-education effect.

• Study Type: Interventional
• Enrollment (Estimated): 34
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Iván A. Cuyul-Vásquez, PhD(c); Phone Number: +56452205205; Email: icuyul@uct.cl

Study Locations

• Chile
  • Araucania
    • Temuco, Araucania, Chile, 4813302
      • UCT, Facultad de ciencias de la Salud
      • Contact: Iván A. Cuyul-Vásquez, PhD(c); Phone Number: +56452205205; Email: icuyul@uct.cl
      • Contact: Cuyul-Vásquez Iván Cuyul-Vásquez, PhD(C); Phone Number: +56452205205; Email: icuyul@uct.cl

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Individuals will be eligible for inclusion if they are right-handed adults aged 18 to 35 years with a body mass index (BMI) between 18.5 and 30 kg/m².
• Individuals must be classified as physically inactive, defined as not meeting the World Health Organization criteria of at least 150 minutes of moderate-intensity physical activity or 75 minutes of vigorous-intensity physical activity per week.

Exclusion Criteria:

• Individuals who have engaged in physical training (e.g., any form of strength or aerobic exercise) or specific manual dexterity training within the past 6 months. - Individuals who regularly participate in artistic, occupational, or sporting activities requiring high levels of manual dexterity (e.g., musicians, gamers, craftspeople).
• Individuals with a history of orthopedic or traumatic injuries affecting either upper extremity. Individuals with pathologies or conditions that preclude safe training (e.g., uncontrolled hypertension, or visual, auditory, or cognitive impairments [for example, dyscalculia]).
• Individuals currently using nutritional supplements or medications that interfere with the regulation of skeletal muscle mass and strength (e.g., whey protein, creatine) or the central nervous system (e.g., antidepressants, anxiolytics, hypnotics).

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Contralateral manual dexterity training; Participants in the experimental group will perform contralateral manual dexterity training focused on moving 0.5, 1.0, or 1.5 kg cylinders using different grips and movements across various planes on a gridded board. Participants will execute various grips to place the cylinders into the quadrants indicated on a smartphone screen.	Other: Contralateral Manual Dexterity Training; The subjects in the experimental group will perform contralateral manual dexterity training focused on moving cylinders of 0.5, 1 or 1.5 kilos with grips and movements in different planes on a gridded board. Participants will have to develop different grips and place the cylinders in the quadrants indicated on a smartphone screen.
No Intervention: Control group without intervention

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fine Manual Dexterity	Fine manual dexterity will be assessed using the Functional Dexterity test (FDT). Using a stopwatch, the evaluator records the total time in seconds that the participant takes to complete the task.	Baseline and day 7
Force control	In a seated position with the elbow flexed, participants will perform isometric contractions to reach a target torque guided by real-time visual feedback. The accuracy of maintaining these contractions in the wrist flexor and extensor muscles will be assessed using a Humac Norm isokinetic dynamometer (Computer Sports Medicine, Inc., Stoughton, MA, USA). Participants will perform a continuous 60-second isometric contraction exercise. During this period, participants will adjust their force level to between 10% and 30% of their maximum voluntary contraction (MVC) at 10-second intervals. Three attempts will be performed per limb. The Root Mean Square Error (RMSE) will be recorded.	Baseline and day 7
Gross Manual Dexterity	This gross manual dexterity will be assessed using the same task performed during the experimental group's contralateral manual dexterity training. Specifically, participants will complete 15 trials, moving cylinders of varying weights across a gridded board following a sequence displayed on a smartphone. The time required to complete these 15 trials will be recorded.	Baseline and day 7

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Handgrip strength	Maximum lumbrical and cylindrical grip strength will be assessed using a Jamar Plus+ digital hand dynamometer. The highest value from three attempts will be recorded for each assessment	Baseline and day 7
Joint Position Sense Test	Proprioception: Wrist flexion-extension joint position sense will be assessed using the Joint Position Sense Test (JPST). All measurements will be conducted with a Humac Norm isokinetic dynamometer (Computer Sports Medicine, Inc., Stoughton, MA, USA). Three attempts will be made per limb. The absolute error (difference in degrees between 30° and the angle achieved during the test) will be recorded.	Baseline and day 7
Left/right judgment	Left/right judgment will be assessed using the Recognise™ application (Noigroup, Adelaide, Australia). Performance on the laterality judgment task was quantified using the Inverse Efficiency Score (IES), calculated as the average reaction time of correct responses divided by the proportion of correct responses (IES = RT / PC). 3 blocks of 20 images (60 images total). Maximum exposure time: 5 seconds per image.	Baseline and day 7

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Physical activity level	Weekly metabolic equivalents (MET-min/week) will be calculated using the validated Spanish version of the Global physical activity questionnaire (GPAQ).	Baseline and day 7
Psychological Distress	Psychological Distress, including symptoms of depression, anxiety, and stress, will be assessed using the 21-item Depression, Anxiety and Stress Scale (DASS-21). This self-report instrument will be used to quantify the severity of emotional distress across these three domains. This scale has a minimum score of 0 and a maximum of 126 points (total score calculated by doubling the sum of the 21 items). Higher scores in DASS-21 indicate greater psychological distress.	Baseline
Sleep Quality:	Sleep disturbances and overall sleep quality will be assessed using the Pittsburgh Sleep Quality Index (PSQI). This scale has a minimum score of 0 and a maximum of 21 points (higher scores indicate worse sleep quality)	Baseline
Daily steps	Physical activity will be monitored using a Xiaomi Band 9 smartwatch (number of daily steps), which participants will wear throughout the seven-day mobilization period.	During 7 days of immobilization
Sleep time	Sleep time will be measured using a Xiaomi Band 9 smartwatch (hours), which participants will wear throughout the seven-day immobilization period.	During 7 days of immobilization

Collaborators and Investigators

• Sponsor: Universidad Catolica de Temuco
• Collaborators: University of Valencia; Universidad de La Frontera

Study record dates

Study Major Dates

• Study Start (Estimated): May 25, 2026
• Primary Completion (Estimated): October 1, 2026
• Study Completion (Estimated): January 30, 2027

Study Registration Dates

• First Submitted: May 14, 2026
• First Submitted That Met QC Criteria: May 22, 2026
• First Posted (Actual): May 29, 2026

Study Record Updates

• Last Update Posted (Actual): May 29, 2026
• Last Update Submitted That Met QC Criteria: May 22, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Immobilization; Cross-education; contralateral training; interlimb transfer
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Nervous System Diseases; Muscular Diseases; Neuromuscular Diseases; Muscular Disorders, Atrophic
• Other Study ID Numbers: INMO-CROSS-2026

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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