Author Identifier

Stuart Guppy

Guy Gregory Haff

Document Type

Journal Article

Publication Title

Sports Biomechanics


Taylor & Francis


School of Medical and Health Sciences / Centre for Exercise and Sports Science Research




Australian Government


This is an Accepted Manuscript of an article published by Taylor & Francis in SPORTS BIOMECHANICS on 22/09/2021, available online:

Guppy, S. N., Brady, C. J., Kotani, Y., Connolly, S., Comfort, P., Lake, J. P., & Haff, G. G. (2021). A comparison of manual and automatic force-onset identification methodologies and their effect on force-time characteristics in the isometric midthigh pull. Sports Biomechanics. Advance online publication.


The aim of this study was to assess the agreement of three different automated methods of identifying force-onset (40 N, 5 SDs, and 3 SDs) with manual identification, during the isometric mid-thigh pull (IMTP). Fourteen resistance-trained participants with > 6 months experience training with the power clean volunteered to take part. After three familiarisation sessions, the participants performed five maximal IMTPs separated by 1 min of rest. Fixed bias was found between 40 N and manual identification for time at force-onset. No proportional bias was present between manual identification and any automated threshold. Fixed bias between manual identification and automated was present for force at onset and F150. Proportional but not fixed bias was found for F50 between manual identification and all automated thresholds. Small to moderate differences (Hedges g = −0.487- −0.692) were found for F90 between all automated thresholds and manual identification, while trivial to small differences (Hedges g = −0.122—−0.279) were found between methods for F200 and F250. Based on these results, strength and conditioning practitioners should not use a 40 N, 5 SDs, or 3 SDs threshold interchangeably with manual identification of force-onset when analysing IMTP force–time curve data.