Reference Values And Level Of Reliability Of The IMTP Test In Chilean High-performance Athletes

The Isometric Mid-Thigh Pull test (IMTP) is widely used for the evaluation of the force-time curve of athletes in different sport due to its relationship with performance. PURPOSE: Determine the reliability and reference values in peak force (PF), impulse and rate of force development (RFD) obtained in the IMTP test of Chilean High Performance athletes. METHODS: 77 high-performance athletes from Chile, 17 women and 58 men, were assessed in the IMTP test between 2019 and 2021. The test was performed on two Pasco PS-2142 strength platforms, using a rack designed for the test. Data were obtained using ®ForceDesks (VALD performance) software. The variables analyzed were: PF, Impulse, RFD at 100, 150 and 200 ms (N/s). The statistical analysis of reliability was determined by Coefficient of Variation (CV) < 5% and Technical Error (TE). RESULTS: The absolute PF of the females was 1837.63 ± 315.35 (N) with a TE of 37.01 (N) and a coefficient of variation (CV) of 2.01%. The average impulse at 100 ms was 82.19 ± 16.70 (Ns), TE = 2.7 (Ns) and CV = 3.3%; at 150 ms was 136.76 ± 33.18 (Ns), TE = 6.80 (Ns) and CV = 4.98%; and at 200 ms was 199.48 ± 46.74 (Ns), TE = 7.20 (Ns) and CV = 3.6%. Respect to RFD at 100 ms the average was 2455 ± 1237.25 (N/s), TE = 299.99 (N/s) and CV = 12.09%; at 150 ms averaged 2958.28 ± 1148.14 (N/s), TE = 267.89 (N/s) and CV = 9.06%; and at 200 ms the average was 3168.25 ± 974.95 (N/s), TE = 204.65 (N/s) and CV = 6.45%. Respect to men, the average PF was 2511.86 ± 440.25 (N), TE = 56.26 (N) and CV = 2.4%. The average impulse at 100 ms was 109.83 ± 22.24 (Ns), TE = 5.08 (Ns) and CV = 4.63%; at 150 ms was 180.60 ± 36.97 (Ns), TE = 9.29 (Ns) and CV = 4.93%.; and at 200 ms was 280.89 ± 52.26 (Ns), TE = 13.11 (Ns) and CV = 4.67%. Regarding RFD at 100 ms the average was 5041.26 ± 2697.56 (N/s), TE = 1049.96 (N/s). and CV = 20.83%; at 150 ms was 5297.80 ± 2025.95 (N/s), TE = 793.97 (N/s) and CV = 14.99% at 200 ms was 5054.66 ± 1496.81 (N/s), TE = 626.77 (N/s) and CV = 12.40%. CONCLUSIONS: The results show that the CV less than 5% correspond to the PF and impulse variables in both men and women. The RFD at 100 ms, in both men and women, showed the highest CV. These results are useful since they show reference values in variables widely used in IMTP and their reliability.