Force-velocity relationship in Paralympic powerlifting: two or multiple-point methods to determine a maximum repetition

Abstract

Background: Due to the absence of evidence in the literature on Paralympic Powerlifting the present study investigated various methods to assess bench press maximum repetition and the way each method influences the measurement of minimum velocity limit (MVT), load at zero velocity (LD0), and force-velocity (FV).

Objective: To evaluate the precision of the multi-point method using proximal loads (40, 50, 60, 70, 80, and 90% of one repetition maximum; 1RM) compared to the four-point method (50, 60, 70, and 80% of 1RM) and the two-point method using distant loads (40 and 80% and 50 and 80% of 1RM) in in the MVT, LD0, and FV, in bench press performed by Paralympic Powerlifters (PP).

Methods: To accomplish this, 15 male elite PP athletes participated in the study (age: 27.7 ± 5.7 years; BM: 74.0 ± 19.5 kg). All participants performed an adapted bench press test (free weight) with 6 loads (40, 50, 60, 70, 80, and 90% 1RM), 4 loads (50, 60, 70, and 80% 1RM), and 2 loads (40-80% and 50-80% 1RM). The 1RM predictions were made by MVT, LD0, and FV.

Results: The main results indicated that the multiple (4 and 6) pointsmethod provides good results in the MVT (R² = 0.482), the LD0 (R² = 0.614), and the FV (R² = 0.508). The two-point method (50-80%) showed a higher mean in MVT [1268.2 ± 502.0 N; ICC95% 0.76 (0.31-0.92)], in LD0 [1504.1 ± 597.3 N; 0.63 (0.17-0.86)], and in FV [1479.2 ± 636.0 N; 0.60 (0.10-0.86)].

Conclusion: The multiple-point method (4 and 6 points) and the two-point method (40-80%) using the MVT, LD0, and FV all showed a good ability to predict bench press 1RM in PP.

Keywords: Force–velocity relationship; Load estimation; Multiple-load method; Paralympics; Powerlifting.

Fig. 1

Experimental approach. RM: Repetition Maximum

Fig. 2

Linear Regression Model through the Force–Velocity relation between bar velocity and different percentages of 1 repetition maximum (1RM) in the Adapted Bench Press with free weight, in the minimum velocity limit (MVT), load at zero velocity (LD0) and velocity of force (FV). In each column are the linear regression line and the prediction equation based on 6 points (40, 50, 60, 70 80 and 90%), 4 points (50, 60, 70, 80%), 2 points (40–80%) and 2 points (50–80%)

Fig. 2

Linear Regression Model through the Force–Velocity relation between bar velocity and different percentages of 1 repetition maximum (1RM) in the Adapted Bench Press with free weight, in the minimum velocity limit (MVT), load at zero velocity (LD0) and velocity of force (FV). In each column are the linear regression line and the prediction equation based on 6 points (40, 50, 60, 70 80 and 90%), 4 points (50, 60, 70, 80%), 2 points (40–80%) and 2 points (50–80%)

Fig. 3

Results of predicted values at 6, 4, 40–80% and 50% using the Minimum Velocity Limit (MVT), Load at Zero Velocity (LD0) and velocity of force (FV) methods in relation to the measured value of 1RM and confidence interval of the test. No significant differences were found in any of the methods in relation to the 1RM assessed (p < 0.05)

Fig. 4

Results for predicted velocity values (ms-1) at 6, 4, 40–80% and 50% using the Minimum Velocity Limit (MVT), Load at Zero Velocity (LD0) and velocity of force (FV) in relation to the predicted values and confidence interval of the test

Fig. 5

Bland–Altman plots showing differences between the parameters obtained from the 6-point and 4-point load method, and two points (40–80% and 50–80%) in the minimum velocity Limit (MVT), Load at zero velocity (LD0) and velocity of force (FV). Each graph represents the mean difference and 95% limits of agreement (dashed lines), along with the regression line (solid line)