Simplifying strength assessment and prescription. Predictive model for biceps 1RM based on isometric dynamometry and biometric data: A pilot study.

BACKGROUND

Estimating one-repetition maximum (1RM) is critical for safe and effective resistance training prescription, yet traditional testing can be time-consuming or contraindicated in some populations. This study aimed to develop a predictive model for biceps curl 1RM using biometric measures and handheld dynamometry.

METHODS

Thirty-one adults (15 trained and 16 sedentary) participated. Data collected included age, height, weight, sex, peak isometric elbow flexion force (via handheld dynamometer), and handgrip strength. Due to significant biometric differences between groups, statistical analysis focused on sedentary participants. Pearson correlation and linear regression were used to evaluate the relationship between 1RM and isometric strength.

RESULTS

Isometric biceps strength showed a strong correlation with 1RM (R = 0.8608). Linear regression demonstrated substantial predictive value (R2 = 0.74, p < 0.001). Trained participants exhibited significantly higher 1RM-to-isometric strength ratios compared to sedentary individuals (73.17 % vs. 52.93 %, p < 0.01).

CONCLUSION

Isometric elbow flexion force measured via handheld dynamometry is a strong predictor of biceps curl 1RM. These preliminary findings suggest its potential utility in guiding resistance training prescriptions, particularly in populations where maximal testing is impractical or unsafe.