Recovery of Force-Time Characteristics After Australian Rules Football Matches: Examining the Utility of the Isometric Midthigh Pull.

Purpose: This study assessed the utility of force-time characteristics from the isometric midthigh pull (IMTP) as a measure of neuromuscular function after elite-level Australian rules football matches. It was hypothesized that rate characteristics of force development would demonstrate a different response magnitude and recovery time course than peak force measurements.
Methods: Force-time characteristics of the IMTP (peak force, 0- to 50-ms rate of force development [RFD], 100- to 200-ms RFD) were collected at 48 (G+2), 72 (G+3), and 96 h (G+4) after 3 competitive Australian rules football matches.
Results: Meaningful reductions (>75% of the smallest worthwhile change) were observed at G+2, G+3, and G+4 for RFD 0-50 milliseconds (-25.8%, -17.5%, and -16.9%) and at G+2 and G+3 for RFD 100-200 milliseconds (-15.7% and -11.7%). No meaningful reductions were observed for peak force at any time point (G+2 -4.0%, G+3 -3.9%, G+4 -2.7%). Higher week-to-week variation was observed for RFD 0-50 milliseconds (G+2 17.1%, G+3 27.2%, G+4 19.3%) vs both RFD 100-200 milliseconds (G+2 11.3%, G+3 11.5%, G+4 7.2%) and peak force (G+2 4.8%, G+3 4.4%, G+4 8.4%). Conclusions: These findings highlight the potential use of rate characteristics from the IMTP as measures of neuromuscular function in elite sport settings, and in particular RFD 100-200 milliseconds due to its higher reliability. Interestingly, peak force collected from the IMTP was not meaningfully suppressed at any time point after elite Australian rules football match play. This suggests that rate characteristics from IMTP may provide more sensitive and valuable insight regarding neuromuscular function recovery kinetics than peak measures.