Effects of Different Stiffness Settings During Robotic Isokinetic Training in Children With SMA

NCT07822711 | Not Yet Recruiting

• 1 other identifier: 2026-536-02
• Study Type: interventional
• Target: 13
• Locations: 1 country
• Sites: 1

Brief Summary

This randomized, within-participant, contralateral-limb-controlled clinical trial will compare individually optimized compliant and rigid stiffness settings of a portable isokinetic knee training robot in children with spinal muscular atrophy. At least 13 children aged 6 to 12 years will be enrolled. For each participant, one leg will be randomly assigned to the compliant setting and the contralateral leg to the rigid setting using sequentially numbered, opaque, sealed envelopes. Both legs will receive the same training volume, number of repetitions, and angular velocity for up to 8 weeks. The primary outcome is the between-setting difference in the change from baseline in peak isokinetic knee-extension torque. Secondary outcomes include knee-extension range of motion, quadriceps cross-sectional area on magnetic resonance imaging, femoral nerve conduction measures, and sit-to-stand performance. Knee pain, suprapatellar skin temperature, fatigue, and other adverse events will be monitored throughout the study.

Conditions

Spinal Muscular Atrophy (SMA)

Outcome Measures

Primary Outcomes (1)

• Between-setting difference in the change from baseline in peak knee-extension torque

  Peak isokinetic knee-extension torque will be measured separately for each limb using the portable isokinetic knee training robot and reported in newton-meters. For each participant, the change from baseline will be calculated for the compliant-setting limb and the rigid-setting limb. The primary outcome is the within-participant difference between these two changes: (post-intervention minus baseline change for the compliant setting) minus (post-intervention minus baseline change for the rigid setting).

  Baseline and immediately after the intervention period, up to 8 weeks

Secondary Outcomes (4)

• Between-setting difference in the change from baseline in active knee-extension range of motion

  Baseline and immediately after the intervention period, up to 8 weeks

• Between-setting difference in the change from baseline in quadriceps cross-sectional area

  Baseline and immediately after the intervention period, up to 8 weeks

• Between-setting difference in the change from baseline in femoral nerve compound muscle action potential amplitude

  Baseline and immediately after the intervention period, up to 8 weeks

• Change from baseline in the minimum initial knee angle for successful sit-to-stand performance

  Baseline and immediately after the intervention period, up to 8 weeks

Study Arms (2)

Scheme A: Left Compliant, Right Rigid

EXPERIMENTAL

Participants assigned to scheme A will receive isokinetic knee training with the individually optimized compliant stiffness setting on the left leg and the rigid stiffness setting on the right leg. Training dose, angular velocity, number of repetitions, number of sets, and rest periods will be matched between the two legs.

Device: Portable Isokinetic Knee Training Robot With an Individually Optimized Compliant Setting; Device: Portable Isokinetic Knee Training Robot With a Rigid Setting

Scheme B: Left Rigid, Right Compliant

EXPERIMENTAL

Participants assigned to scheme B will receive isokinetic knee training with the rigid stiffness setting on the left leg and the individually optimized compliant stiffness setting on the right leg. Training dose, angular velocity, number of repetitions, number of sets, and rest periods will be matched between the two legs.

Device: Portable Isokinetic Knee Training Robot With an Individually Optimized Compliant Setting; Device: Portable Isokinetic Knee Training Robot With a Rigid Setting

Interventions

Portable Isokinetic Knee Training Robot With an Individually Optimized Compliant Setting DEVICE

The compliant setting will be individualized within the device's predefined safe stiffness range. At each candidate stiffness, the participant will perform five knee-extension repetitions. The stiffness producing the highest mean peak knee-extension torque while the movement remains painless, without obvious fatigue, and with a stable trajectory will be selected. The assigned limb will then train at this setting for up to 8 weeks, no more than five sessions per week. Each session will use a target angular velocity of 45 degrees per second, an individualized maximum voluntary pain-free range of motion, at least six sets of 10 extension-flexion repetitions per leg, and approximately 1 minute of rest between sets. Training volume will be matched to the contralateral limb.

Scheme A: Left Compliant, Right Rigid; Scheme B: Left Rigid, Right Compliant

Portable Isokinetic Knee Training Robot With a Rigid Setting DEVICE

The assigned limb will train with the device's predefined rigid stiffness setting for up to 8 weeks, no more than five sessions per week. Each session will use a target angular velocity of 45 degrees per second, an individualized maximum voluntary pain-free range of motion, at least six sets of 10 extension-flexion repetitions per leg, and approximately 1 minute of rest between sets. Training volume will be matched to the contralateral limb.

Scheme A: Left Compliant, Right Rigid; Scheme B: Left Rigid, Right Compliant

Eligibility Criteria

• Age: 6 Years - 12 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17)

You may qualify if:

• Age 6 to 12 years.
• Diagnosis of spinal muscular atrophy.
• Able to maintain an independent seated position.
• If receiving disease-modifying treatment, including nusinersen or risdiplam, the participant must have received a stable dose for at least 6 months before enrollment and must not change the treatment regimen during the study.

You may not qualify if:

• Any other major disease or medical condition that, in the investigator's judgment, would interfere with safe participation or interpretation of the study results.
• The legal guardian declines to provide written informed consent, or the participant is unable to complete the study procedures.
• Unable to undergo magnetic resonance imaging or electromyography and nerve conduction testing.
• Blood pressure above the 95th percentile for age, sex, and height, as assessed by a clinician.
• Lacks the cognitive capacity to understand or comply with the requirements of study participation.

Sponsors & Collaborators

• Peking University Third Hospital: lead

Study Sites (1)

Peking University Third Hospital

Beijing, 100191, China

Location

MeSH Terms

Conditions

Muscular Atrophy, Spinal

Condition Hierarchy (Ancestors)

Spinal Cord Diseases; Central Nervous System Diseases; Nervous System Diseases; Motor Neuron Disease; Neurodegenerative Diseases; Neuromuscular Diseases

Central Study Contacts

Fuzhen Yuan, Dr.

CONTACT

+8613111050197; tildaren@163.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Attending Physician, Department of Sports Medicine

Model Details: Randomized within-participant split-body design. Each participant receives both stiffness settings concurrently, one on each lower limb. Randomization determines only the left-right assignment: scheme A assigns the compliant setting to the left leg and the rigid setting to the right leg, whereas scheme B assigns the rigid setting to the left leg and the compliant setting to the right leg. Outcomes for the two settings are compared within each participant.

Study Record Dates

• First Submitted: September 13, 2026
• First Posted: September 16, 2026
• Study Start: September 21, 2026
• Primary Completion (Estimated): January 15, 2027
• Study Completion (Estimated): January 30, 2027
• Last Updated: September 16, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)