Investigating the effects of unilateral lower limb immobilization and re-training in healthy young and older men and women. Musculoskeletal Diseases
Conditions
Interventions
Current interventions as of 05/11/2025:
Participants will undergo 10 days of unilateral lower limb suspension using a sling to restrict movements and simulate muscle disuse. During this period, part
Sponsors
University of Basel
Eligibility
Sex/Gender
All
Age
18 Years to 74 Years
Inclusion criteria
Inclusion criteria: Current key inclusion criteria as of 28/07/2026: 1. Healthy men and women aged 18 to 30 years (young) as well as older adults (60-74 years) - active persons performing 1-3 active sessions per week 2. Willing and physically able to undergo the study demands (immobilization period and retraining exercises) 3. Daily tasks should not require them to be physically active during the immobilization period 4. Be able to travel to the facilities of the Department of Sports, Exercise and Health, University of Basel for the measurement sessions and three times per week to complete the retraining period 5. Be able to travel 5 times to the Department of Sports, Exercise and Health and to the University Hospital Basel for the measurement sessions 6. All participants will receive a medical examination and need medical clearance for participation 7. Signed informed consent _____ Previous key inclusion criteria as of 05/11/2025: 1. Healthy men and women aged 18 to 30 years (young) as well as older adults (60-70 years) - active persons performing 1-3 active sessions per week 2. Willing and physically able to undergo the study demands (immobilization period and retraining exercises) 3. Daily tasks should not require them to be physically active during the immobilization period 4. Be able to travel to the facilities of the Department of Sports, Exercise and Health, University of Basel for the measurement sessions and three times per week to complete the retraining period 5. Be able to travel 5 times to the Department of Sports, Exercise and Health and to the University Hospital Basel for the measurement sessions 6. All participants will receive a medical examination and need medical clearance for participation 7. Signed informed consent _____ Previous key inclusion criteria: 1. Age Groups: Young adults (18-35 years) and older adults (>65 years). 2. Health Status: Primarily healthy individuals living independently in the community. 3. Physical Ability: Participants must be physically capable of undergoing the study demands, including immobilization and retraining. 4. Daily Activity Requirements: Daily tasks should not require participants to be physically active during the immobilization period. 5. Travel Availability: Participants must be able to travel to the Department of Sports, Exercise, and Health at the University of Basel for the retraining phase. 6. Medical Clearance: All participants must undergo a medical examination and receive medical clearance to participate.
Exclusion criteria
Exclusion criteria: Current key exclusion criteria as of 05/11/2025: 1. History of cardiovascular, pulmonary or chronic inflammatory disease 2. Personal or family history of blood clots 3. Orthopaedic problems or surgery (within the last 6 months) 4. Body mass index >35 kg/m2 5. Pregnancy 6. History of osteoporosis or a recent (past 6 months) low-trauma fracture 7. Use of assistive walking device within the previous year 8. Expecting to travel abroad throughout the intervention 9. Participants who do not agree to the collected data being made available in coded form (open science) 10. History of cancer within the past 5 years 11. Current use of oral contraceptives with esrtogen or oestrogenic hormone therapy 12. Usual contraindications to MRI as defined in the clinical practice _____ Previous key exclusion criteria: 1. Medical Conditions: 1.1. History of cardiovascular, pulmonary, or chronic inflammatory diseases. 1.2. Personal or family history of blood clots. 1.3. Allergy to heparin (used for anticoagulation during immobilization). 2. Orthopedic Issues: 2.1. Recent orthopedic surgery (within the last six months). 2.2. Existing orthopedic problems that could interfere with participation. 3. Body Composition: 3.1. Body mass index (BMI) > 30 kg/m². 4. Bone Health: 4.1. History of osteoporosis. 4.2. Recent (past six months) low-trauma fracture. 5. Mobility and Functional Restrictions: 5.1. Use of assistive walking devices within the previous year. 5.2. Expectation of travel during the intervention period. 6. Pregnancy: 6.1. Pregnant individuals will be excluded.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Primary outcomes will be assessed before and after the disuse period as well as after the retraining period. Furthermore, the primary outcomes will be assessed in a mid-training test. 1.Knee extensor and flexor strength – Measured using isometric dynamometry to assess maximum voluntary contractions but also the rate of force development of knee extensors and knee flexors. 2.Balance performance – Evaluated using single-leg stance and tandem stance on a force platform. 3.Gait analysis– Gait analyses will be done using an optoelectric walkway to assess gait parameters such walking speed, stride length, or stride variability. | — |
Secondary
| Measure | Time frame |
|---|---|
| Secondary outcomes will be assessed before and after the disuse period as well as after the retraining period. 1. Voluntary Activation of knee extensors – The twitch-interpolation technique will be used to assess the level of voluntary activation of knee extensor muscles. 2. Muscle architecture and contractility – Muscle contractility during voluntary contractions will be assessed using dynamic ultrasound. Different parameters of muscle architecture and contractility such as fascicle length, pennation angle, fascicle shortening velocity, amount of shortening and changes in pennation angle will be assessed for the Vastus lateralis muscle during maximum voluntary contractions. 3. Muscular activation – High-density electromyography (HD-EMG) is a non-invasive technique to measure the electrical activity produced by skeletal muscles. HD-EMG signals will be recorded from the musculus vastus lateralis during contractions of different contraction intensities. A grid of electrodes will be used to assess central and peripheral properties of motor units. 4. Tendon stiffness – The stiffness of the patellar tendon will be assessed using dynamic ultrasonography. An ultrasound probe will therefore be fixated on the patellar tendon during a ramped isometric knee extension contraction. 5. Muscle and tendon volume and muscle strain – A magnetic resonance imaging (MRI) scanner will be used to assess muscle and tendon parameters such as muscle and tendon volume. Additionally, dynamic MRI to determine muscle deformation and strain will be performed in combination with neuromuscular electrical stimulation. 6. Anthropometry – Whole body as well as lower limb skeletal muscle mass, fat mass, lean mass, bone mineral density and bone mineral content will be obtained using dual-energy x-ray absorptiometry. 7. Blood pressure – Brachial blood pressure will be measured in a supine position after 10 min of rest using an automatic blood pressure monitor. 8. Accelerometry – Participants will be aske | — |
Countries
Switzerland
Contacts
Public ContactMartin Keller
Outcome results
None listed