{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T21:09:14Z","timestamp":1780434554478,"version":"3.54.1"},"reference-count":50,"publisher":"PeerJ","license":[{"start":{"date-parts":[[2024,10,4]],"date-time":"2024-10-04T00:00:00Z","timestamp":1728000000000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:sec>\n               <jats:title>Background<\/jats:title>\n               <jats:p>Repeat power ability (RPA) assessments traditionally use discrete variables, such as peak power output, to quantify the change in performance across a series of jumps. Rather than using a discrete variable, the analysis of the entire force-time curve may provide additional insight into RPA performance. The aims of this study were to (1) analyse changes in the force-time curve recorded during an RPA assessment using statistical parametric mapping (SPM) and (2) compare the differences in the force-time curve between participants with low and high RPA scores, as quantified by traditional analysis.<\/jats:p>\n            <\/jats:sec>\n            <jats:sec>\n               <jats:title>Materials and Methods<\/jats:title>\n               <jats:p>Eleven well-trained field hockey players performed an RPA assessment consisting of 20 loaded countermovement jumps with a 30% one repetition maximum half squat load (LCMJ20). Mean force-time series data was normalized to 100% of the movement duration and analysed using SPM. Peak power output for each jump was also derived from the force-time data and a percent decrement score calculated for jumps 2 to 19 (RPA<jats:sub>%dec<\/jats:sub>). An SPM one-way ANOVA with significance accepted at <jats:italic>\u03b1<\/jats:italic>\u00a0=\u00a00.05, was used to identify the change in the force-time curve over three distinct series of jumps across the LCMJ20 (series 1 = jumps 2\u20135, series 2 = jumps 9\u201312 and series 3 = jumps 16\u201319). A secondary analysis, using an independent <jats:italic>T<\/jats:italic>-test with significance accepted at <jats:italic>p<\/jats:italic>\u00a0&lt;\u00a00.001, was also used to identify differences in the force-time curve between participants with low and high RPA<jats:sub>%dec<\/jats:sub>.<\/jats:p>\n            <\/jats:sec>\n            <jats:sec>\n               <jats:title>Results<\/jats:title>\n               <jats:p>Propulsive forces were significantly lower (<jats:italic>p<\/jats:italic>\u00a0&lt;\u00a00.001) between 74\u201398% of the movement compared to 0\u201373% for changes recorded during the LCMJ20. <jats:italic>Post hoc<\/jats:italic> analysis identified the greatest differences to occur between jump series 1 and jump series 2 (<jats:italic>p<\/jats:italic>\u00a0&lt;\u00a00.001) at 70\u201398% of the movement and between jump series 1 and jump series 3 (<jats:italic>p<\/jats:italic>\u00a0&lt;\u00a00.001) at 86\u201399% of the movement. No significant differences were found between jump series 2 and jump series 3. Significant differences (<jats:italic>p<\/jats:italic>\u00a0&lt;\u00a00.001) in both the braking phase at 44\u201348% of the jump and the propulsive phase at 74\u201394% of the jump were identified when participants were classified based on low or high RPA<jats:sub>%dec<\/jats:sub> scores (with low scores representing an enhanced ability to maintain peak power output than high scores).<\/jats:p>\n            <\/jats:sec>\n            <jats:sec>\n               <jats:title>Conclusion<\/jats:title>\n               <jats:p>A reduction in force during the late propulsive phase is evident as the LCMJ20 progresses. SPM analysis provides refined insight into where changes in the force-time curve occur during performance of the LCMJ20. Participants with the lower RPA<jats:sub>%dec<\/jats:sub> scores displayed both larger braking and propulsive forces across the LCMJ20 assessment.<\/jats:p>\n            <\/jats:sec>","DOI":"10.7717\/peerj.17971","type":"journal-article","created":{"date-parts":[[2024,10,4]],"date-time":"2024-10-04T07:45:04Z","timestamp":1728027904000},"page":"e17971","source":"Crossref","is-referenced-by-count":5,"title":["Changes in the force-time curve during a repeat power ability assessment using loaded countermovement jumps"],"prefix":"10.7717","volume":"12","author":[{"given":"Alex O.","family":"Natera","sequence":"first","affiliation":[{"name":"Sport Science, New South Wales Institute of Sport, Sydney Olympic Park, New South Wales, Australia"},{"name":"Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Steven","family":"Hughes","sequence":"additional","affiliation":[{"name":"Sport Science, 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