Publications

ME Hoffman, R Abuatiq, K Bokowy, AL Fiss, J Looper, KM Steele (2026) “Up and down: analyzing physical activity and posture with wearable sensors during partial bodyweight supported play for young children with down syndrome”

Ally Clarke EarlyMobility, JournalArticle, News, Projects, Publications , , ,

Journal Article in Developmental Neurorehabilitation

Children with Down syndrome commonly experience delays in motor milestones, such as pulling to stand and walking, due to musculoskeletal factors associated with DS like hypotonia and ligament laxity

Aim: Understanding how to support age-appropriate motor exploration while increasing movement, physical activity and upright time is essential for optimizing developmental and health outcomes in young children with Down syndrome. Open-area partial bodyweight support (PBWS) systems can help support motor development, but no study has objectively reported motor behavior changes, such as increased leg activity or time spent upright.  

Methods: This randomized, multisite crossover trial included children with Down syndrome who could sit independently but were not yet walking. Each child completed nine 30-minute play-based sessions with and without PBWS. Physical activity and posture were measured using shank-worn accelerometers, capturing the percentage of time spent in high physical activity and upright. Nonparametric Mann-Whitney U tests compared outcome measures between PBWS and non-PBWS conditions.

Results: Fifteen children (mean age: 19.4 months, range: 12–31 months) completed study procedures. Across all participants, high physical activity did not noticeably increase from the first to last session. The median change was −5.0% (IQR: −13.4- +9.05%) with PBWS and −2.53% (IQR: −13.7- +12.9%) without PBWS. Time spent on feet showed a median increase of +2.38% with PBWS (IQR: −0.96 – +12.24) and a decrease of −1.08% without PBWS (IQR: −7.70 - + 1.02%). A statistically significant difference between conditions (p = .042) indicated greater improvements in time on feet during PBWS sessions versus without.

Interpretation: PBWS did not increase time spent in high physical activity, but did support increased upright posture over time. These findings suggest PBWS systems may provide a supportive environment for practicing upright postures in early motor development for children with Down syndrome.

(A) The enriched exploratory play space with the PBWS system (B) Actigraph GT3X+ triaxial accelerometers were placed on a child’s right shank. (C) This study used a randomized crossover study design. Nine children had PBWS assistance first, and 6 children second. Each intervention period lasted 3 weeks. (D) The accelerometers were used to calculate physical activity and upright posture.

HA Feldner, K Keithley, KA Ingraham, A Fragomeni, N Zaino, A Sinclair, AN Meltzoff, PK Kuhl, KM Steele (2026) “Learning powered mobility: caregiver perceptions of young children’s capabilities and device impact”

Ally Clarke EarlyMobility, JournalArticle, News, Projects, Publications , , , ,

Journal Article in Disability and Rehabilitation: Assistive Technology

Self-initiated mobility experiences are critical for young children with disabilities and may be augmented through powered mobility.

(A) A child participant driving the Permobil ® Explorer Mini (photo courtesy of the IMPACT Collaboratory). (B) Specifications of the Explorer Mini device.

Aim: The purpose of this study was to understand caregiver perceptions of powered mobility intervention following a 12-session trial of a novel powered mobility device.  

Methods: Ten caregivers (4 M/6F) of children with cerebral palsy (Gross Motor Function Classification System IV-V) and other developmental disabilities (21.8 ± 5.9 months). Children participated in 12 in-lab driving sessions (exploratory or goal directed) using the Explorer Mini (Permobil AB, Sweden). Exit interviews were conducted with caregivers at the final visit, transcribed verbatim, coded inductively, and analysed until themes emerged.

Results: Four themes emerged from the data: (1) Changing views of capability and adaptability; (2) Emerging autonomy; new skills in and out of the device; (3) Clear need and benefit with some drawbacks; and (4) Lingering stigma and uncertainty 

Interpretation: PM trial positively shifted caregiver’s perceptions of both PM in general and their child’s capabilities, with a desire for greater access to PM at home to support development. These beliefs remained juxtaposed with lingering stigma for some caregivers about PM devices, and a stated desire for more modifiable PM options for children with different positioning or access needs.

Dynamic Walking 2026

Ally Clarke Energetics, MotorControl, Presentation, Projects , , ,

Members of the lab traveled to the base of Mt. Rainier for the Dynamic Walking Conference, where conversations ranged from hummingbird drumming to exoskeletons and robotics.

Dr. Kat Steele was selected to give a 20-minute talk, “Bayesian methods for individualized modeling with wearable data.” PhD student Ally Clarke gave a 5-minute talk on energy savings from bodyweight support in children with cerebral palsy, sharing results from our Cerebral Palsy Energetics study . PhD student Mackenzie Pitts also gave a 5-minute talk on her work from the Dynamic Motor Control study, discussing the mechanical strategies children with cerebral palsy use to adapt step length during split-belt treadmill walking.

We loved reconnecting with former lab members Dr. Michael Rosenberg, Dr. Momona Yamagami, and Tori Landrum.

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AK Clarke, AJ Ries, MH Schwartz, KM Steele (2026) “Influence of body weight support on motor control in typically developing children and children with cerebral palsy”

Katie Energetics, JournalArticle, Publications , , ,

Journal Article in Journal of Biomechanics

For children with cerebral palsy (CP), interventions that provide support like BWS treadmill training, orthoses, or walkers have been shown to improve walking speed, endurance, and/or kinematics – although responses are variable and challenging to predict.

Experimental setup. Body weight support is provided via vertical force application at the pelvis by the support system (Humotech, force controller, and overhead gantry). Electromyography was recorded bilaterally from seven lower limb muscles.

Aim: Body weight support (BWS) is often provided during rehabilitation interventions or activities of daily living with assistive devices for children with cerebral palsy (CP). How individuals alter their muscle activity and coordination in response to BWS provides insight into neuromuscular control and may inform the design of future interventions.

Methods: Children with CP (n = 12) and typically developing (TD) peers (n = 8) walked on a treadmill with 1%, 20%, 40%, and 60% BWS while electromyographic (EMG) data was recorded from 7 lower limb muscles. We computed muscle synergies from the EMG data using non-negative matrix factorization.

Results: As BWS increased, activity of support muscles like the gluteus maximus and gluteus medius decreased for both CP and TD groups. Children with CP had significantly reduced synergy complexity compared to TD peers (total variance accounted for by one synergy, tVAF1 = 76.3 for CP versus 67.4 for TD averaged across all conditions). However, synergy complexity did not change with BWS for either group.

Interpretation: Although BWS may assist mobility by reducing demand on support muscles, it does not directly modulate motor control.

Neuromechanics & Mobility Lab at the 2026 Undergraduate Research Symposium

Katie News, Presentation ,

Congratulations to the Neuromechanics & Mobility Lab undergraduates who presented their research at the University of Washington’s 29th Annual Undergraduate Research Symposium on May 15! From oral presentations to posters, our students shared work spanning early mobility, gait analysis, and neuromodulation — proud moment for the whole lab.

Oral Presentations

Early Intervention Providers’ Perspectives on a Switch-Accessible Play Kit Analyzed Through an Interdependence Framework Alisha Bose (mentored by Mia Hoffman)

Muscular Coactivation Analysis in Toddlers with Hypotonia Spencer Hensley (mentored by Mia Hoffman)

Poster Presentations

Real-Time Bayesian Estimation of Steady-State Oxygen Consumption During Clinical Walking Trials for Neuromuscular-Impaired Individuals David Green (mentored by Mackenzie Pitts)

Object Detection Optimization for Movement Tracking of Young Children Using Mobility Aids Katie Leija (mentored by Mia Hoffman)

Effects of Bodyweight Support on the Gait Deviation Index of Children with Cerebral Palsy Alyssa Miller (mentored by Ally Clarke)

Evaluating the Effects of Transcutaneous Spinal Cord Stimulation on Perceived Walking Performance and Exertion in Children with Cerebral Palsy Quinn Mundell (mentored by Madeleine McCreary)

Huge thanks to the graduate student mentors who supported these projects, and congratulations to all our presenters on a fantastic symposium!