Table 2. Systematic bias, random error, proportional bias, and heteroscedasticity for one-repetition maximum (1RM) estimation methods. Method m ± 1.96SD, kg Systematic Bias Proportional Bias Heteroscedasticity p ES r2 p r2 p Actual MVT -0.4 ± 14.3 0.838 -0.02 0.385 0.018* 0.351 0.026* Optimal MVT 1.2 ± 18.3 0.646 0.07 0.504 0.004* 0.181 0.130 50% 1RM 1.2 ± 29.1 0.765 0.08 0.150 0.171 0.074 0.345 70% 1RM 4.8 ± 20.4 0.111 0.32 0.093 0.290 0.009 0.746 80% 1RM -0.5 ± 11.9 0.778 -0.03 0.581 0.002* 0.060 0.398 90% 1RM 2.1 ± 14.0 0.294 0.13 0.456 0.008* 0.364 0.022* ES, Cohen’d effect size; MVT, minimal velocity threshold; r2, goodness-of-fit.