Predicting 1 Repetition Maximum Squat With Peak Force Obtained From Isometric Squat at Multiple Positions

Area of Science:

• Sports Science
• Biomechanics
• Strength and Conditioning

Background:

• Accurate prediction of one-repetition maximum (1RM) squat is crucial for training prescription.
• Isometric squat assessments offer a potential alternative to dynamic 1RM testing.

Purpose of the Study:

• To determine if peak force (PF) from isometric squats (IsoSqt) at multiple knee angles can precisely predict 1RM squat.
• To compare the predictive accuracy of group-based versus gender-specific regression models.

Main Methods:

• Twenty-nine resistance-trained athletes performed 1RM squats and IsoSqt at 60°, 90°, and 120° knee angles.
• Peak force data from IsoSqt were correlated with 1RM squat performance.
• Linear regression analyses were conducted using group, male-only, and female-only data.

Main Results:

• Peak force from all tested isometric squat positions significantly correlated with 1RM squat (r = 0.684–0.940).
• Linear regression models demonstrated high predictive power (R² = 0.826–0.903).
• Gender-specific models predicted 1RM squat with higher precision than group-based models, showing minimal differences from actual 1RM values.

Conclusions:

• Peak force derived from isometric squats at multiple knee angles effectively predicts 1RM squat performance.
• Utilizing gender-specific regression equations enhances the precision of 1RM squat predictions.
• Isometric squat peak force offers a viable method for estimating maximal squat strength.