Feasibility of the two-point method to determine the load-velocity relationship variables during the countermovement jump exercise

Purpose: This study aimed to examine the reliability and validity of load-velocity relationship variables obtained through the two-point method using different load combinations and velocity variables.

Methods: Twenty men performed two identical sessions consisting of two countermovement jumps against four external loads (20-40-60-80 kg) and a heavy squat against a load linked to a mean velocity of 0.55 m·s-1 (load0.55). The load-velocity relationship variables (load-axis intercept [L0], velocity-axis intercept [v0], and area under the load-velocity relationship line [Aline]) were obtained using three velocity variables (mean velocity [MV], mean propulsive velocity [MPV], and peak velocity [PV]) by the multiple-point method including (20-40-60- 80-load0.55) and excluding (20-40-60-80) the heavy squat, as well as from their respective twopoint methods (20-load0.55, and 20-80).

Results: The load-velocity relationship variables were obtained with an acceptable reliability (CV≤7.30%; ICC≥0.63). The reliability of L0 and v0 was comparable for both methods (CVratio=1.11-1.12), but the multiple-point method provided Aline with a greater reliability (CVratio=1.26). The use of a heavy squat provided the load-velocity relationship variables with a comparable or higher reliability than the use of a heavy countermovement jump load (CVratio=1.06-1.19). The PV provided the load-velocity relationship variables with the greatest reliability (CVratio=1.15-1.86) followed by MV (CVratio=1.07-1.18), and finally MPV. The twopoint methods only revealed an acceptable validity for MV and MPV (ES≤0.19; r≥0.96; CCC≥0.94).

Conclusions: The two-point method obtained from a heavy squat load and MV or MPV is a quick, safe, and reliable procedure to evaluate the lower-body maximal neuromuscular capacities through the load-velocity relationship.