Nenad Nedović1,2, Milica Vidović1, Dragana Vukov1, Danilo Vujičić1, Stevan Jovanović1,3, Panagiotis Chatzistergos4, Žiga Kozinc5,6
1Academy of Applied Studies Belgrade, College of Health Sciences, Serbia
2University of Belgrade, Institute for Medical Research, Belgrade, Serbia
3University of Kragujevac, Faculty of Medical Sciences, Kragujevac, Serbia
4School of Science and Engineering, University of Dundee, Dundee, UK
5University of Primorska, Faculty of Health Sciences, Izola, Slovenia
6Ludwig Boltzmann Institute for Rehabilitation Research, Vienna, Austria
Surface Effects on the Enhanced Paper Grip Test Results in Healthy Adults
Monten. J. Sports Sci. Med. 2027, 16(1), 3-11 | DOI: 10.26773/mjssm.270307
Abstract
The enhanced paper grip test (EPGT) offers a practical approach to foot-strength assessment, but variation in testing surfaces may affect comparability across field settings. This study examined surface effects and within-session reliability in 20 healthy adults (20–68 years). Participants completed three trials per leg on paper, cardboard and linoleum. Surface comparisons used the mean of three peak-force measurements. Attachment–material friction was characterized separately under controlled loading. Repeated-measures ANOVA with Greenhouse–Geisser correction detected no surface effect (right: p = 0.384; left: p = 0.221). All descriptive 95% confidence intervals for paired mean differences included zero. Single-trial consistency reliability was excellent (ICC(3,1) = 0.955–0.980), increasing for three-trial means (ICC(3,3) = 0.985–0.993). Single-trial typical error was 3.45–6.01 N (CV = 7.8–12.5%). Surface correlations were strong to very strong (r = 0.789–0.936), but Bland–Altman limits indicated variable individual agreement; the widest limits were −36.77 to 40.71 N. Skewed differences limit interpretation of these normal-theory limits. A sample-size sensitivity analysis indicated 80% power for a two-sided paired effect of dz = 0.660. No systematic surface-dependent differences were detected, but small effects and individual discrepancies cannot be excluded. Neither surface interchangeability nor a negligible biological role of friction was established.
Keywords
enhanced paper grip test, toe flexor strength, surface comparability
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