Intra-subject sample size effects in plantar pressure analyses

PeerJ

article

Juliet McClymont¹  Russell Savage¹  Todd C. Pataky²  Robin Crompton¹  James Charles¹  Karl T. Bates¹ 

[1] Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences, University of Liverpool;Department of Human Health Sciences, Kyoto University Graduate School of Medicine

关键词: Plantar pressure;    Variability;    Walking;    Gait;    Biomechanics;   

DOI  :  10.7717/peerj.11660

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Background500 records per subject) has demonstrated seemingly high levels of step-to-step variation in peak plantar pressure within human individuals during walking. One intuitive consequence of this variation is that smaller sample sizes (e.g., 10 steps per subject) may be quantitatively and qualitatively inaccurate and fail to capture the variance in plantar pressure of individuals seen in larger data sets. However, this remains quantitatively unexplored reflecting a lack of detailed investigation of intra-subject sample size effects in plantar pressure analysis.Methods500 steps per subject) to compare variability in three metric types at sample sizes of 5–400 records: (1) overall whole-record mean and maximum pressure; (2) single-pixel values from five locations across the foot; and (3) the sum of pixel-level variability (measured by mean square error, MSE) from the whole plantar surface.Results200 steps. However, <200 steps, and particularly 400 steps. The range in pixel-level MSE at low subsamples (500 pressure records per subject. Overall, therefore, we demonstrate a high probability that the very small sample sizes (n < 20 records), which are routinely used in human and animal studies, capture a relatively low proportion of variance evident in larger plantar pressure data set, and thus may not accurately reflect the true population mean.

【 授权许可】

CC BY