Effects of a Machine Learning-based Lower Limb Exercise Training System for Knee Pain

June 2, 2026 updated by: The University of Hong Kong

Development and Randomized Controlled Trial of an AI-powered Technological Surrogate Physiotherapist (TSP) Dedicated to Quality Enhancement and Cost Reduction in Knee Osteoarthritis Exercise Rehabilitation

The goal of the study is to confirm the idea of AI-powered Technological Surrogate Physiotherapist (TSP), by demonstrating its effectiveness and value as a new technology-based contribution to OA healthcare. Participants will be randomized to one of two groups: (1) the conventional PT group receiving the exercise program delivered through in-person sessions; or (2) the AI-guided group following the program through the TSP after an initial PT session. All individuals will take part in the study for 12 weeks, and data will be collected at baseline and 12 weeks after randomization.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Knee pain, often caused by osteoarthritis, is a prevalent musculoskeletal disorder among older adults and significantly reduces physical function and quality of life. Exercise therapy has been shown to be an effective form of treatment for knee pain. However, the traditional delivery of exercise therapy requires that individuals attend clinics to participate in face-to-face exercise sessions, which can be expensive and inconvenient. In recent years, information technologies have been used to support the delivery of exercise programs. The programs have also shown great benefits in improving the management of knee pain. However, it remains a concern that physical therapists are not able to provide the patients with direct and immediate supervision when exercises are taken place remotely at home or in community centers, which can be detrimental to exercise performance and the management of knee pain.

Thus, the research team has developed a machine learning-based exercise training system to provide evidence-based lower limb exercise videos, real-time movement feedback, and tracking of exercise progress for older adults with knee pain. In this study, a 12-week randomized controlled non-inferiority trial will be conducted to compare the effects of the AI-powered Technological Surrogate Physiotherapist with those of in-person physiotherapy sessions.

Study Type

Interventional

Enrollment (Estimated)

176

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Calvin Kalun Or, PhD
  • Phone Number: (852) 3917-2587
  • Email: klor@hku.hk

Study Locations

  • Hong Kong
      • Hong Kong, Hong Kong, 000
        • 826, Haking Wong Building, Pokfulam, The University of Hong Kong, Hong Kong
        • Contact:
          • Kalun Or, Doctoral degree
          • Phone Number: (852) 3917-2587
          • Email: klor@hku.hk
        • Sub-Investigator:
          • Letong Li, Master degree

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

55 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion criteria:

  1. At least 50 years of age;
  2. Report having knee pain most days of the week;
  3. Has radiographic evidence of grade 2, 3, or 4 knee OA on the K-L scale in the posteroanterior and/or skyline view in at least 1 knee;
  4. Willing and able, both physically and cognitively, to perform the exercises required in the study protocol;
  5. Has normal or corrected-to-normal vision;
  6. Able to speak Cantonese and read Chinese, AND
  7. Able to provide written informed consent.

Exclusion criteria:

  1. Having a history of knee or hip replacement surgery;
  2. Being nonambulatory;
  3. Having systemic inflammatory arthritis (e.g., gout);
  4. Having a history of trauma (e.g., fractures around the knee, dislocation, sprains or tears of soft tissues like ligaments) or surgical arthroscopy of either knee within the past 6 months;
  5. Having intra-articular injection to the knee within the past 6 months;
  6. Having cognitive impairment;
  7. Involvement in a similar study (i.e., involving physical exercise or physical therapies for knee pain) within the past 6 months;
  8. Undergoing recent or imminent surgery (within 3 months) , OR
  9. Having medical co-morbidities that preclude participation in exercise.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: The AI-powered Technological Surrogate Physiotherapist
Participants will be required to perform three 30-minute exercise sessions per week for 12 weeks, with six exercises at any one time. During the exercise sessions, participants will receiveTechnological Surrogate Physiotherapist (TSP) support which will in particular leverage AI to offer innovative features and modules dedicated to enhancing exercise monitoring and supervision, real-time performance feedback, and self-assessment.
Device: The AI-powered Technological Surrogate Physiotherapist

The AI-powered Technological Surrogate Physiotherapist will have three key features:

  1. Evidence-based exercise videos instructed by physical therapists
  2. Real-time movement feedback and performance score
  3. Exercise records.
Active Comparator: Face-to-face physiotherapist-supervised exercise program
Participants will be required to visit a physiotherapist for usual face-to-face exercise therapy. Also, they will be required to perform three 30-minute home exercise sessions per week for 12 weeks. However, TSP will not be involved in this group.
Behavioral: Face-to-face physiotherapist-supervised exercise program
Physiotherapists will give usual face-to-face therapy. The assessment of participants' exercise movements will only be achieved in the traditional manner during face-to-face exercise sessions - by physiotherapists' visual inspection of and professional judgement on postural alignment and effectiveness, with verbal instructions for posture correction. The features of real-time movement feedback and tracking of exercise progress will not be provided.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in knee pain as assessed by a 11-point numerical pain rating scale as recommended by the OARSI
Time Frame: From baseline to 12 weeks
0 represents no pain and 10 represents the worst possible pain.
From baseline to 12 weeks
Changes in physical function as assessed by the Knee Injury and Osteoarthritis Outcome Score (KOOS) physical function sub-scale
Time Frame: From baseline to 12 weeks
The scale regards the degree of difficulty in performing usual daily activities and higher level activities that involve physical function of the knee. Each item will be rated on a 5-point Likert scale ranging from 'None' (i.e., no difficulty) to 'Extreme' (i.e., extreme difficulty), based on which a normalized total score will be calculated (0 indicating extreme symptoms and 100 indicating no symptoms).
From baseline to 12 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in physical function as assessed by 30-second chair-stand test
Time Frame: From baseline to 12 weeks
30-second chair stand test (30CST), which measures the number of stands the participant can complete in 30 sec, will be used to assess the general leg strength and functional performance.
From baseline to 12 weeks
Changes in physical function as assessed by timed up-and-go test
Time Frame: From baseline to 12 weeks
Timed up and go (TUG) test, which measures the time it takes the participant to standup from the chair, walk 3 meters, walk back to the chair, and sit down, will be used to assess functional mobility.
From baseline to 12 weeks
Changes in physical function as assessed by maximal isometric strength of the quadriceps and hamstrings
Time Frame: From baseline to 12 weeks

The participant will be instructed to maximally extend/flex each knee for 3 trials, 3 sec each, with a 1-minute rest in between. Verbal encouragement will be given in each trial to ensure the participant makes the maximum effort. The highest force of each muscle in the three trials will be used for data analysis.

After each test trial, the severity of pain experienced by the participant during the trial will be assessed using the 11-point numerical pain rating scale.
From baseline to 12 weeks
Exercise adherence
Time Frame: From baseline to 12 weeks
Exercise adherence will be indicated by the proportion of sessions and proportion of exercises performed which will be recorded by the TSP system (only for intervention group) and by participants and researchers using a log book.
From baseline to 12 weeks
Satisfaction with the therapeutic exercise training
Time Frame: From baseline to 12 weeks
It will be rated by participants using a 7-point Likert scale with anchors of 'Extremely unsatisfied' and 'Extremely satisfied'.
From baseline to 12 weeks
Convenience in terms of location and time for accessing the exercise therapy
Time Frame: From baseline to 12 weeks
It will be assessed on an 11-point numerical rating scale, with 0 representing 'Extremely inconvenient' and 10 representing 'Extremely convenient'.
From baseline to 12 weeks

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in acceptance of the interventions
Time Frame: from baseline to 4 weeks, 8 weeks, and 12 weeks
The technology acceptance model will be used to examine the particpants' acceptance of interventions (i.e., machine learning-based exercise training system or video-based exercise training system). There will be four constructs: perceived usefulness (4 items), perceived ease of use (4 items), attitude (3 items), and intention to use (2 items). Each item will be rated on a 7-point Likert scale, ranging from 1 (very strongly disagree) to 7 (very strongly agree).
from baseline to 4 weeks, 8 weeks, and 12 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

The University of Hong Kong

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

May 20, 2026

Primary Completion (Estimated)

June 30, 2027

Study Completion (Estimated)

September 1, 2027

Study Registration Dates

First Submitted

December 9, 2021

First Submitted That Met QC Criteria

December 10, 2021

First Posted (Actual)

December 29, 2021

Study Record Updates

Last Update Posted (Actual)

June 4, 2026

Last Update Submitted That Met QC Criteria

June 2, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Feedback System

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

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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