Differential neuromuscular fatigue responses in multi- and single-joint force following a simulated soccer protocol in youth players: evidence for divergent assessment sensitivity

Abstract

The purpose of the present study was to compare the time-dependent sensitivity of the countermovement jump (CMJ), isometric mid-thigh pull (IMTP), and isometric hamstring 90–90 (IH90–90) tests in detecting neuromuscular fatigue following a standardized soccer simulation protocol (T-SAFT90) in young male soccer players. Eighteen young male soccer players (age 19.0 ± 1.2 years; height 1.78 ± 0.06 m; body mass 72.2 ± 7.8 kg; playing experience 5.6 ± 1.97 years) participated in a randomized cross-over study design. Neuromuscular function was assessed before, immediately post, and 24- and 48 h post-T-SAFT90. A repeated-measures ANOVA revealed significant protocol × time interactions for all measures (all p ≤ .015) except IMTP force at 100 and 200 ms (p ≥ .305). Post hoc comparisons showed trivial-to-large reductions from baseline (g = − 0.81 to 0.00) with distinct time courses. IH⁹⁰⁻⁹⁰ net peak force showed the greatest and most prolonged sensitivity, being reduced at all time points (post, 24 h and 48 h; p ≤ .017, g = − 0.81 to − 0.39). IMTP peak and relative peak force were reduced at post and 24 h before returning towards baseline at 48 h, whereas CMJ height was reduced only at 24 h, whereas RSImod was reduced at both 24 and 48 h, consistent with a strategy-related preservation of jump height. IH⁹⁰⁻⁹⁰ rapid force was reduced at 24 h (100 ms) and at 24 and 48 h (200 ms); given the limited reliability of the rapid-force variables, these outcomes are considered exploratory. These findings support the use of force-plate assessments for fatigue monitoring, with different tests capturing distinct aspects of neuromuscular function and recovery. Practitioners may therefore select assessments according to the timing and purpose of monitoring during congested training and match periods in young soccer players, with the IH⁹⁰⁻⁹⁰ appearing the most sensitive across the recovery timeline. (ClinicalTrials.gov identifier: NCT07623343). 29/05/2026. Retrospectively registered.