The Impact of Real-Time Visual Feedback on Maximal Force Output and Reliability During Isometric MidThigh Pull Testing in Resistance-Trained Men

Accurate and valid assessment of the maximal force production is essential for athlete monitoring and training prescription in sports science. This study investigated the impact of visual feedback on force output and measurement reliability in isometric mid-thigh pull (IMTP). Twenty resistance-trained men completed three variations of the IMTP test (single, repeated, and 30 s all-out) across four sessions, with two sessions conducted with feedback and two without. Peak and mean force output was analyzed using peak and mean values. Data from the best testing day (i.e., highest force output in each variation) were used for comparisons between conditions, whereas test–retest reliability was assessed using data from the two sessions under the same condition. Visual feedback significantly enhanced most measures of peak and mean force outputs in all test variations (effect sizes ranging from 0.49 to 1.13 and p < 0.001–0.006). Reliability analyses of the single and repeated repetitions revealed that feedback reduced coefficients of variation (range: 2.57%–5.17% vs. 3.11%–6.92%) and yielded higher intraclass correlation coefficients (range: 0.961–0.983 vs. 0.898–0.987), indicating improved consistency both within sessions and between testing days. However, in the 30 s all-out test, feedback did not significantly improve reliability, possibly due to pacing strategies influenced by the real-time display. These findings demonstrate that real-time visual feedback enhances both performance and reliability in strength testing, with important implications for research and applied sports science.