A robotic-assisted intervention (ROBERT®) to enhance muscle strength in the hip flexor muscles following spinal cord injury: A pilot within-person randomized controlled trial

Susanne Lillelund Sørensen; Anette Bach Jønsson; Lisa A. Harvey; Fin Bierings-Sørensen; Jørgen Feldbæk Nielsen

doi:10.1080/10790268.2025.2488573

A robotic-assisted intervention (ROBERT®) to enhance muscle strength in the hip flexor muscles following spinal cord injury: A pilot within-person randomized controlled trial

Susanne Lillelund Sørensen, Anette Bach Jønsson, Lisa A. Harvey, Fin Bierings-Sørensen, Jørgen Feldbæk Nielsen

Department of Clinical Medicine - Hammel Neurocenter, Universitetsklinik for Neurorehabilitering

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

Abstract

Objective: To determine whether a robotic-assisted intervention increases hip flexor muscle strength in people with spinal cord injury (SCI) and marked neurological weakness. The robotic-device (ROBERT®) supports the weight of the leg and guides it through assisted active or resisted active hip flexion movements. Study design: Pilot within-person randomised controlled trial. Setting: Specialized SCI center in Denmark. Methods: Twelve people with incomplete SCI <12 months, aged ≥18 and grade 1-3/5 strength on a Manual Muscle Test in the right and left hip flexor muscles were recruited. One leg of each person was randomised to receive additional ROBERT® treatment. All other care remained the same for both legs. Randomization was stratified based on hip flexor muscle strength. Treatment of the experimental leg consisted of 60 assisted active or resisted active hip flexion movements with the robotic device three times a week for eight weeks. The primary outcome was maximal voluntary isometric contraction (MVIC). Secondary outcomes were root mean square of a surface electromyography signal, muscle thickness, the number of hip flexion movements per day, and self-reported perception of function and strength. Participants were assessed at baseline and post-intervention. Results: Eleven out of 12 participants completed the study. There were no statistically significant between-group differences for MVIC (mean and 95% CI was −2.7 Nm, −8.1 to 2.7) or any of the secondary outcomes (except the number of hip flexion movements per day). Conclusion: The robotic-assisted intervention did not increase hip flexor strength in people with incomplete SCI and marked neurological weakness.

Original language	English
Journal	The Journal of Spinal Cord Medicine
ISSN	1079-0268
DOIs	https://doi.org/10.1080/10790268.2025.2488573
Publication status	E-pub / Early view - 2025

Keywords

Muscle strength
Pilot within-peron randomized controlled trial
Robotic-assisted intervention
Spinal cord injury

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10.1080/10790268.2025.2488573

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Lillelund Sørensen, S., Jønsson, A. B., Harvey, L. A., Bierings-Sørensen, F., & Nielsen, J. F. (2025). A robotic-assisted intervention (ROBERT®) to enhance muscle strength in the hip flexor muscles following spinal cord injury: A pilot within-person randomized controlled trial. The Journal of Spinal Cord Medicine. Advance online publication. https://doi.org/10.1080/10790268.2025.2488573

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title = "A robotic-assisted intervention (ROBERT{\textregistered}) to enhance muscle strength in the hip flexor muscles following spinal cord injury: A pilot within-person randomized controlled trial",

abstract = "Objective: To determine whether a robotic-assisted intervention increases hip flexor muscle strength in people with spinal cord injury (SCI) and marked neurological weakness. The robotic-device (ROBERT{\textregistered}) supports the weight of the leg and guides it through assisted active or resisted active hip flexion movements. Study design: Pilot within-person randomised controlled trial. Setting: Specialized SCI center in Denmark. Methods: Twelve people with incomplete SCI <12 months, aged ≥18 and grade 1-3/5 strength on a Manual Muscle Test in the right and left hip flexor muscles were recruited. One leg of each person was randomised to receive additional ROBERT{\textregistered} treatment. All other care remained the same for both legs. Randomization was stratified based on hip flexor muscle strength. Treatment of the experimental leg consisted of 60 assisted active or resisted active hip flexion movements with the robotic device three times a week for eight weeks. The primary outcome was maximal voluntary isometric contraction (MVIC). Secondary outcomes were root mean square of a surface electromyography signal, muscle thickness, the number of hip flexion movements per day, and self-reported perception of function and strength. Participants were assessed at baseline and post-intervention. Results: Eleven out of 12 participants completed the study. There were no statistically significant between-group differences for MVIC (mean and 95% CI was −2.7 Nm, −8.1 to 2.7) or any of the secondary outcomes (except the number of hip flexion movements per day). Conclusion: The robotic-assisted intervention did not increase hip flexor strength in people with incomplete SCI and marked neurological weakness.",

keywords = "Muscle strength, Pilot within-peron randomized controlled trial, Robotic-assisted intervention, Spinal cord injury",

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A robotic-assisted intervention (ROBERT®) to enhance muscle strength in the hip flexor muscles following spinal cord injury: A pilot within-person randomized controlled trial. / Lillelund Sørensen, Susanne ; Jønsson, Anette Bach; Harvey, Lisa A. et al.
In: The Journal of Spinal Cord Medicine, 2025.

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

TY - JOUR

T1 - A robotic-assisted intervention (ROBERT®) to enhance muscle strength in the hip flexor muscles following spinal cord injury

T2 - A pilot within-person randomized controlled trial

AU - Lillelund Sørensen, Susanne

AU - Jønsson, Anette Bach

AU - Harvey, Lisa A.

AU - Bierings-Sørensen, Fin

AU - Nielsen, Jørgen Feldbæk

PY - 2025

Y1 - 2025

N2 - Objective: To determine whether a robotic-assisted intervention increases hip flexor muscle strength in people with spinal cord injury (SCI) and marked neurological weakness. The robotic-device (ROBERT®) supports the weight of the leg and guides it through assisted active or resisted active hip flexion movements. Study design: Pilot within-person randomised controlled trial. Setting: Specialized SCI center in Denmark. Methods: Twelve people with incomplete SCI <12 months, aged ≥18 and grade 1-3/5 strength on a Manual Muscle Test in the right and left hip flexor muscles were recruited. One leg of each person was randomised to receive additional ROBERT® treatment. All other care remained the same for both legs. Randomization was stratified based on hip flexor muscle strength. Treatment of the experimental leg consisted of 60 assisted active or resisted active hip flexion movements with the robotic device three times a week for eight weeks. The primary outcome was maximal voluntary isometric contraction (MVIC). Secondary outcomes were root mean square of a surface electromyography signal, muscle thickness, the number of hip flexion movements per day, and self-reported perception of function and strength. Participants were assessed at baseline and post-intervention. Results: Eleven out of 12 participants completed the study. There were no statistically significant between-group differences for MVIC (mean and 95% CI was −2.7 Nm, −8.1 to 2.7) or any of the secondary outcomes (except the number of hip flexion movements per day). Conclusion: The robotic-assisted intervention did not increase hip flexor strength in people with incomplete SCI and marked neurological weakness.

AB - Objective: To determine whether a robotic-assisted intervention increases hip flexor muscle strength in people with spinal cord injury (SCI) and marked neurological weakness. The robotic-device (ROBERT®) supports the weight of the leg and guides it through assisted active or resisted active hip flexion movements. Study design: Pilot within-person randomised controlled trial. Setting: Specialized SCI center in Denmark. Methods: Twelve people with incomplete SCI <12 months, aged ≥18 and grade 1-3/5 strength on a Manual Muscle Test in the right and left hip flexor muscles were recruited. One leg of each person was randomised to receive additional ROBERT® treatment. All other care remained the same for both legs. Randomization was stratified based on hip flexor muscle strength. Treatment of the experimental leg consisted of 60 assisted active or resisted active hip flexion movements with the robotic device three times a week for eight weeks. The primary outcome was maximal voluntary isometric contraction (MVIC). Secondary outcomes were root mean square of a surface electromyography signal, muscle thickness, the number of hip flexion movements per day, and self-reported perception of function and strength. Participants were assessed at baseline and post-intervention. Results: Eleven out of 12 participants completed the study. There were no statistically significant between-group differences for MVIC (mean and 95% CI was −2.7 Nm, −8.1 to 2.7) or any of the secondary outcomes (except the number of hip flexion movements per day). Conclusion: The robotic-assisted intervention did not increase hip flexor strength in people with incomplete SCI and marked neurological weakness.

KW - Muscle strength

KW - Pilot within-peron randomized controlled trial

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KW - Spinal cord injury

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DO - 10.1080/10790268.2025.2488573

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C2 - 40323257

SN - 1079-0268

JO - The Journal of Spinal Cord Medicine

JF - The Journal of Spinal Cord Medicine

ER -

A robotic-assisted intervention (ROBERT®) to enhance muscle strength in the hip flexor muscles following spinal cord injury: A pilot within-person randomized controlled trial

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