Association of strength and plyometric exercises with change of direction performances

Abstract

The change of direction (COD) ability is an important task-specific skill for success in team sports, dependent on both strength and reactive strength. The sprint approaching the COD and degrees of the turn are factors influencing the specificity of the COD. Thus, CODs have been suggested to be categorized as force-(> 90˚) and velocity-dominant (< 90˚) dependent on the degree of the turn. When training programmes fail to provide a significant increase in COD performance, it is often due to neglecting the task-specific demands of the COD. As such, 23 male football players volunteered to complete a randomized controlled trial, investigating the association of maximal strength and power performance with performance in a force-(180˚) and velocity-dominant (45˚) COD, with a 4 m and 20 m sprint approach. Three strength and three plyometric exercises, matched in movement patterns, were used. Muscle activity of the different conditions was also compared. The correlational analysis revealed that better performance in the plyometric tests were associated with less time to complete both force-and velocity-dominant CODs, supported by similarities in muscle activation. None of the performances in strength exercises correlated to COD performance, due to the slow contraction velocity of maximal lifts. It was concluded that plyometrics share more physical similarities with CODs than the strength exercises.

Association of Performance in Strength and Plyometric Tests with Change of Direction Performance in Young Female Team-Sport Athletes

“…The strength tests of the current study were similar to an earlier similar study by Falch, Rædergård, and van den Tillaar [ 29 ], but in men. It consisted of a bilateral back squat, a unilateral quarter squat performed on a Smith machine, and a lateral barbell squat.…”

“…Contradictory to earlier research [ 16 , 29 , 53 , 54 ], the correlation between plyometrics and COD performance was limited. Balance might also account for this finding, because instability may decrease the ability to express power [ 55 , 56 ].…”

“…The plyometric tests were also based on a protocol by Falch, Rædergård, and van den Tillaar [ 29 ] consisting of a unilateral vertical countermovement jump for maximal height (cm) and a unilateral lateral countermovement jump for maximal length (cm), herein referred to as a skate-jump and a drop jump with a drop height of 20 cm [ 40 ], whereby the reactive strength index (RSI) is the performance variable (jump height/ground contact time). In the unilateral vertical countermovement jump and the drop jump, athletes were instructed to place their hands akimbo, to prevent an arm swing from possibly contributing to performance, limiting the isolated effect of leg power [ 41 ].…”

“…Thus, results after conducting training interventions might conflict [ 21 ]. To the authors’ knowledge, a study by Falch et al [ 29 ] is the only one to specifically examine the association of strength and plyometric exercises with force- and velocity-oriented CODs. The study was conducted on male soccer players and suggested that the plyometric exercises should be COD-specific, while the different strength tests revealed only a ‘moderate’ insignificant correlation ( r < 0.41).…”

“…Although earlier research suggests plyometric training to be more COD-specific [ 21 , 23 , 29 ], relative strength might reveal a high association for female athletes in both force- and velocity-oriented CODs, as there might be a “threshold” before further strength gains will not enhance COD performance. Lower-limb strength, commonly dynamically expressed with exercises such as the barbell back squat, might be of even greater importance in force-oriented CODs, as CODs of increased angles require longer ground contact times with greater knee and hip-joint angles [ 22 ].…”