Biology subjects

Golyski, P. R.

Publications and source records attributed to Golyski, P. R..

4 recordsLinked to original sources

bioRxiv2026

An open-source application for applying rapid transient perturbations using a split-belt treadmill

BackgroundThe use of specialized perturbation systems has become an increasingly popular approach for investigating walking stability. By accelerating or decelerating one belt, researchers can induce slip- and trip-like perturbations in a controlled laboratory setting. However, many existing studies rely on specialized perturbation systems that require expertise in device-specific software and handling of the equipment, limiting the accessibility of perturbation-based gait research to laboratories with access to such equipment. To address this limitation, we developed an open-source method capable of inducing slip- and trip-like perturbations using a standard split-belt treadmill. Here, we 1) describe the hardware and software components of the system, 2) validate the applications accuracy and precision, and 3) characterize the stability demands imparted by the perturbations with spatial stability measurements. Measured perturbation onset delay and duration were compared to the desired onset timing and programmed duration in addition to step length, step width, minimum mediolateral margin of stability, and sagittal-plane whole-body angular momentum range during the perturbed and recovery steps. ResultsFive participants with traumatic unilateral transtibial limb loss experienced perturbations consisting of brief, rapid increases or decreases in unilateral treadmill velocity, eliciting a "slip" or "trip". The mean (standard deviation) onset delay was 183.3 (9.7) ms, or 24.18% (1.91%) of stance duration. Mean perturbation duration was 239.90 (7.5) ms, 18.14% longer than the intended duration. The perturbations produced measurable changes in gait stability, such as increased step length during the perturbed step and step width during the subsequent recovery step in addition to increased minimum mediolateral margin of stability and sagittal whole body angular momentum. ConclusionThis open-source method successfully induced instability in individuals with impaired balance, demonstrating its feasibility as an accessible alternative to specialized perturbation systems. Future work will focus on refining both the software and hardware components to further improve timing, accuracy, and consistency.

bioengineering↗

bioRxiv2025

Mechanical energetic contributions of the rectus femoris during perturbed walking

Animals maintain locomotor stability following external perturbations by coordinating muscular responses to produce desired mechanical behavior at different levels of description (e.g., muscle-tendon units, joints, legs). To investigate the role of proximal musculature in responding to perturbations during human walking, here we extend a previous analysis relating joint and leg levels down to the level of the rectus femoris. Using in-vivo B-mode ultrasound processed with a custom automated fascicle tracking application and EMG measurements to drive Hill-type models of muscle force, we investigated mechanical energetics of the rectus femoris in 7 individuals who experienced rapid, transient unilateral belt accelerations during walking. We hypothesized that: H1) the rectus femoris would actively lengthen on the perturbed leg during the perturbed stride and H2) on the contralateral leg the rectus femoris would reflect the mechanical energetic demand at the knee and leg levels. H1 was partially supported, with the rectus femoris fascicles being decoupled from muscle-tendon unit lengthening. H2 was not supported, with the rectus femoris best reflecting the energetic role of the hip, as opposed to the knee or leg. Overall, these findings provide a first estimate of the variety of roles proximal muscles play in maintaining stability and lay the groundwork for additional in-vivo measurement informed multi-scale analyses of perturbed locomotion.

physiology↗

bioRxiv2022

Which lower-limb joints compensate for destabilising energy during walking in humans

Maintaining stability during perturbed locomotion requires coordinated responses across multiple levels of organization (e.g., legs, joints, muscle-tendon units). However, current approaches to investigating such responses lack a "common currency" that is both shared across scales and can be directly related to perturbation demands. We used mechanical energetics to investigate the demands imposed on a leg by a transient increase in unilateral treadmill belt speed targeted to either early or late stance. We collected full body kinematics and kinetics from 7 healthy participants during 222 total perturbations. From across-subject means, we found early stance perturbations elicited no change in net work exchanged between the perturbed leg and the treadmill but net positive work at the overall leg level, and late stance perturbations elicited positive work at the leg/treadmill interface but no change in net work at the overall leg level. Across all perturbations, changes in ankle and knee work from steady state best reflected changes in overall leg work on the perturbed and contralateral sides, respectively. Broadening this paradigm to include joint level (vs. leg level) perturbations and including muscle-tendon unit mechanical energetics may reveal neuromechanical responses used in destabilizing environments which could inform design of balance-assisting devices and interventions. Subject Areasbiomechanics, biomedical engineering, bioengineering

bioengineering↗

bioRxiv2020

Adding carbon fiber to shoe soles does not improve running economy: a muscle-level explanation

In an attempt to improve their distance-running performance, many athletes race with carbon fiber plates embedded in their shoe soles. Accordingly, we sought to establish whether, and if so how, adding carbon fiber plates to shoes soles reduces athlete aerobic energy expenditure during running (improves running economy). We tested 15 athletes during running at 3.5 m/s in four footwear conditions that varied in shoe sole carbon fiber plate bending stiffness. For each condition, we quantified athlete aerobic energy expenditure and performed biomechanics analyses, which included the use of ultrasound imaging to examine soleus muscle dynamics in vivo. Overall, increased footwear bending stiffness lengthened ground contact time (p=0.048), but did not affect ankle (p[≥]0.060), knee (p[≥]0.128), or hip (p[≥]0.076) joint angles or moments. Additionally, increased footwear bending stiffness did not affect muscle activity (all seven measured leg muscles (p[≥]0.146)), stride averaged active soleus volume, (p=0.068) or aerobic power (p=0.458) during running. Hence, footwear bending stiffness does not appear to alter the volume of aerobic energy consuming muscle in the soleus, or any other leg muscle, during running. Therefore, adding carbon fiber plates to shoe soles slightly alters whole-body and calf muscle biomechanics but does not improve running economy.

bioengineering↗