Comparison of Three Eccentric Overload Training Strategies on Power Output and Interlimb Asymmetry in Youth Soccer Players

Abstract

Background: The present study compared the effects of performing the lateral squat exercise in three different formats from eccentric overload training on concentric/eccentric peak/mean power and inter-limb asymmetries in young soccer players. Methods: Forty-five young male (U-17) soccer players were distributed into three groups. Two groups performed the same training volume with both legs, beginning with the weaker leg (SVW, n = 15) or with the stronger leg (SVS, n = 15). The third group executed double volume with the weaker leg and also commenced with such leg (DVW, n = 15) in the lateral squat during a 10-week period. Pre- and post-intervention metrics included concentric and eccentric peak/mean power during the lateral squat test and their corresponding asymmetries. Results: All groups improved all power variables. Concentric mean and peak power asymmetry were substantially reduced in the SVW (ES: 0.89), DVW (ES: 0.43), and in SVW (ES: 1.60). Eccentric mean and peak power asymmetry were also substantially decreased in SVW (ES: 0.81) and in DVW (ES: 0.68). Between-group analyses showed substantially better performance in concentric and eccentric variables with stronger and weaker legs in SVW and DVW groups compared with SVS. Conclusions: Those groups which started with the weaker leg showed greater both power enhancements and reductions on inter-limb asymmetries.

The Effects of Workload Difference Between Limbs in Plyometric and Strength Exercises in Reducing Asymmetry in Change of Direction Ability During Basketball Season

“…This could be because of the fact that these studies did not place more volume on nondominant side but only examined the effects of unilateral or bilateral, iso-inertial or cable resistance training, or certain type of warm-up protocol on interlimb asymmetries (19,24,25). In contrast, previous studies that followed similar strategies of asymmetry reduction (more volume on nondominant limb) were found to be efficient in reducing asymmetry in other abilities (14,22). The deterioration in performance on tests before and after the intervention is consistent with previous research showing that fatigue, which accumulates during the basketball season, impairs neuromuscular performance (26).…”

“…In addition, previous research identified that having a double-volume strategy on nondominant leg would be beneficial for asymmetry reduction (22). However, there are no intervention studies investigating the effects of different workload between limbs (nondominant or dominant side) on interlimb asymmetry in CoD, which has been shown to be an efficient method in other abilities (22). The aim of this study was to investigate the effects of 8-week resistance (Bulgarian split squat) and plyometric (SLCMJ) training, with a workload of 3:1 between the nondominant and dominant sides, on asymmetry in CoDdef.…”

“…Previous research has suggested that unilateral plyometric (consisted of single-leg countermovement jumps [SLCMJs]) and strength (consisted of Bulgarian split squats) training is an effective strategy for interlimb asymmetry reduction (1,27). In addition, previous research identified that having a double-volume strategy on nondominant leg would be beneficial for asymmetry reduction (22). However, there are no intervention studies investigating the effects of different workload between limbs (nondominant or dominant side) on interlimb asymmetry in CoD, which has been shown to be an efficient method in other abilities (22).…”

Long-Term Changes in Vertical Jump, H:Q Ratio and Interlimb Asymmetries in Young Female Volleyball Athletes

“…Although the best training strategy to decrease interlimb differences currently remains unclear, some strategies have been successful in reducing neuromuscular asymmetries. Overall, unilateral strength exercises [ 73 , 74 ], strength and power exercises focusing on the major muscles of the lower body and trunk musculature [ 68 ], and a long-term well-structured multifaceted neuromuscular exercise-based injury prevention program with a combination of muscular strength as well as proprioceptive balance and stabilization exercises were likely to have been beneficial to reduce some important interlimb asymmetries related to sports performance and injury risk [ 75 , 76 , 77 ]. Third, the training sessions in the court with specific volleyball technical skills had a relatively high volume, which could reinforce the existing asymmetries or reduce the possible benefits of the neuromuscular training by the concurrent training effect [ 78 ].…”