Prediction of thruster maximum load using clean and jerk one-repetition maximum: influence of gender and experience in CrossFit athletes.

Background: Strength coaches use the repetition maximum (1RM) of key movements to predict the load for derivate exercises in sports like weightlifting or CrossFit (CF). Although this is a fundamental CF exercise, no prediction equations have been established for the thruster (TH). Therefore, this study aimed to determine the relationship between the clean and jerk (CJ) and TH 1RM in CF athletes and analyze the influence of gender and experience.

Methods: Seventy-three participants (40 men; 33 women; age: 30.1±8.2 years) with ≥3 months of CF experience were enrolled in this study. The CJ and TH 1RM were tested in 2 separate sessions. Additionally, anthropometric data and CF experience were taken. Linear correlation and regression analyses were applied to investigate the relationship between both exercises. For further analyses, participants were subdivided by gender and CF-experience (men and women experienced [EM; EW]): ≥24 months CF-training, and (men and women beginners [BM; BW]): <24 months CF-training.

Results: Very high significant (P<0.001) correlations were found between CJ and TH (r=0.98) across all participants and for EM (r=0.98), BM (r=0.96), EW (r=0.95), and BW (r=0.90). Similarly, the coefficient of determination was high to very high for all participants (R²=0.97) and for all the groups; EM (R²=0.97), BM (R²=0.91), EW (R²=0.91), and BW (R²=0.82). Prediction equations were calculated for EM (CJ=0.81*TH+9.98), BM (CJ=0.80*TH+10.23), EW (CJ=0.63*TH+17.39), and BW (CJ=0.96*TH+-2.21).

Conclusions: This is the first study on CF athletes that guides prescribing individualized loads in the TH which is essential to induce appropriate training stimuli to achieve the desired adaptions.