Skylar Holmes

All Publications

• Sex-Specific Associations Between Body Mass Index and Knee Flexion Kinematics and Kinetics in Individuals With Anterior Cruciate Ligament Reconstruction JOURNAL OF SPORT REHABILITATION Smith, M. D., Holmes, S. C., Heredia, C. E., Shumski, E. J., Pamukoff, D. N. 2025: 512-520

  Abstract

  Pedometers are a useful measure of physical activity (PA) but whether systematic bias exists when using differing inclusion criterion for pedometer-derived PA data is unknown. We undertake an exploration of previously published criteria for pedometer data cleaning and examine the impact of different inclusion criteria on sample size retention and participant exclusion by key sociodemographic characteristics.Data were drawn from a community survey in Aotearoa/New Zealand. Sociodemographic information and self-reported PA were collected via face-to-face surveys; participants were asked to wear a Yamax CW300 pedometer for 7 days. Analyses involved removing extreme outliers and determining minimum steps per day for inclusion, determining whether day 1 removal was required, examining risk of bias using different inclusion criteria, and examining convergent and concurrent validity of criteria with the lowest bias potential.Pedometer data were available for 895 participants. A threshold of 100 steps/day was deemed appropriate to define a valid day. All days were correlated with each other; intraclass correlation coefficients were low and did not change meaningfully with removal of the first day of data. Participant retention reduced, and bias in participant inclusion increased, with increasing stringency of data inclusion criterion applied. Evidence for convergent and concurrent validity in the 2 models with the lowest risk of exclusion bias was demonstrated.Increasing stringency in pedometer data inclusion criteria can result in significant and biased loss of sample size. Clear reporting of data cleaning methods and rationale (including consideration of potential for bias) is needed in pedometer-based PA research.

  View details for DOI 10.1123/jsr.2024-0167

  View details for Web of Science ID 001484648200001

  View details for PubMedID 39914378

• KNEE EXTENSOR MUSCLE FATIGUE ALTERS GAIT MECHANICS AND ACTIVATION PATTERNS IN OLDER ADULTS WITH KNEE OSTEOARTHRITIS Holmes, S. C., Kent, J. A., Martini, D. N., Bigelow, C., Boyer, K. ELSEVIER SCI LTD. 2025

  View details for Web of Science ID 001529022600075

• Sex-Specific associations between hip muscle strength and foot progression angle. Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology Holmes, S. C., Montgomery, M. M., Lynn, S. K., Pamukoff, D. N. 2023; 68: 102723

  Abstract

  The foot progression angle (FPA) influences knee loading during gait, but its determinants are unclear. The purpose of this study was to compare FPA between males and females and also examine the association between lower extremity kinematics during gait, hip strength, and the FPA. 25 males and 25 females completed 5 gait trials while FPA and frontal and transverse plane hip and knee angles were calculated from the dominant limb during the foot flat portion of stance. Hip extensor/flexor, abductor/adductor, and internal/external rotator strength were evaluated using maximum voluntary isometric contractions. One-way MANOVAs compared gait and strength outcomes. Stepwise regression assessed the association between FPA, and MVIC and kinematics after accounting for speed in males and females. There was no difference in FPA between sexes (p > 0.05), but females had greater frontal and transverse plane hip angles compared with males (all p < 0.05). Greater hip abduction (p = 0.02) strength was associated with greater FPA, but only in males. In males, greater hip abductor strength may contribute to a more neutral position of the foot during gait, which could help maintain an equal knee loading distribution. Our results suggest that there are sex specific control strategies to achieve a similar FPA during gait.

  View details for DOI 10.1016/j.jelekin.2022.102723

  View details for PubMedID 36402073

• Knee extensor functional demand in individuals with knee osteoarthritis. Gait & posture Holmes, S. C., Boyer, K. A. 2022; 96: 265-270

  Abstract

  Knee extensor (KE) weakness is commonly exhibited in individuals with knee osteoarthritis (KOA) and may contribute to disability due an increased muscle functional demand and resulting compensatory gait strategies during locomotion. Muscle functional demand is defined as the percentage of maximal strength that is used during a task.The study aim was to quantify KE functional demand in KOA, the impact of walking speed and the relationships with the relative joint contribution to total limb work.Fourteen individuals with symptomatic KOA underwent gait analysis at preferred and faster speeds and isokinetic dynamometry for KE maximum voluntary isometric torque. The KE functional demand as well as the relative and peak joint work and powers were calculated. Paired samples t-test was used to compare functional demand and relative work between speeds and Pearson's correlation was used to assess the relationship between relative work and functional demand values (α = 0.05).The KE functional demand was 36.0 ± 15.7 % for the preferred speed and significantly higher at 49.8 ± 16.1 % for the faster speed, (t(13) = -5.45, p .05). Knee flexion moment was also significantly higher for the faster speed (t(13) = -5.54, p .001). There were significant relationships between fast speed functional demand and relative ankle negative power (r = -0.57) and relative ankle positive work (r = 0.66), (all p .05).The results suggest that as functional demand nears or exceeds 50 % of the muscle capacity individuals with KOA reduce the relative effort at the knee and use an ankle-based compensation strategy to meet task demands.

  View details for DOI 10.1016/j.gaitpost.2022.06.005

  View details for PubMedID 35709610