The Effects of Training Interventions on Interlimb Asymmetries: A Systematic Review With Meta-analysis

Abstract

Interlimb asymmetries have been recently investigated in athletic populations. However, the effects of training interventions on interlimb asymmetries have been scarcely examined. Therefore, the aim of this study was to determine the effects of training interventions on changes in interlimb asymmetries from pre- to post-training. Furthermore, to examine the effects of training programs on intervention groups compared with control groups. A database search was completed (MEDLINE, CINAHL, and SPORTDiscus). Eight studies were then included in the meta-analysis. Results showed small reductions in interlimb asymmetries in single-leg broad jump (SLBJ) and change of direction (COD) speed from pre- to post-training interventions, whereas moderate effects were found in single-leg countermovement jump (SLCMJ) and SL lateral jump. When comparing the training interventions with the control groups, results showed small effects in favor of the training groups for reducing interlimb asymmetries in SLBJ and large effects in SLCMJ and COD speed. Thus, training interventions can evoke small to moderate reductions in interlimb asymmetries from pre- to post-training programs. Strength training performed unilaterally or bilaterally may elicit these reductions. Furthermore, training interventions showed larger effects compared with the control groups in reducing interlimb asymmetries. However, further research is needed.

Measuring Interlimb Asymmetry for Strength and Power: A Brief Review of Assessment Methods, Data Analysis, Current Evidence, and Practical Recommendations

“…A recent meta-analysis by Bettariga et al (9) investigated the effects of training interventions on interlimb asymmetries, measured across a range of physical performance tests. In summary, the asymmetry tests most commonly used to demonstrate changes in side-to-side differences are a range of unilateral jump and change of direction (COD) speed tests.…”

“…In addition, the training implemented may not have been ideal for achieving eccentric overload (43), which is an important feature of flywheel training (4). In particular, the ability to produce demanding eccentric phases may be particularly important for developing strength, optimizing performance, and potentially reducing interlimb asymmetries (4,9,28). Although multidirectional and lateral flywheel exercises both improved sport performance parameters, their impact on interlimb asymmetry is not as clear.…”

“…Although flywheel training has been investigated with a variety of populations relating to strength, power, and athletic performance (1,6,52,65)—less is known about its efficacy in reducing interlimb asymmetries (9,28). Flywheel training exercises ranging from (bilateral, unilateral, lateral) squats to multidirectional movements have been applied with the objective of reducing interlimb asymmetries (27,31,43).…”

“…Regarding tests used, several jump and strength tests have been devised for the evaluation of interlimb asymmetry and are often used as key criterion markers alongside performance parameters with athletes that are either healthy or returning to sport after injury (23,51). Given the importance of lower-limb strength and power for athletic populations (9), the assessment of asymmetry for these physical capacities seems especially relevant and valid.…”

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

“…Furthermore, it has been commonly assumed that interlimb asymmetry in magnitude of 10–15% is a reasonable threshold for a safe return to play after an injury, but this assumption has recently been questioned because of the task-specific nature of interlimb asymmetries (34). Nevertheless, one of the goals of strength and conditioning practitioners is to reduce interlimb asymmetries, but the efficient strategy for reducing interlimb asymmetries is still an open question (2). An increase in the number of games, associated with shorter periods of preseason and off-season, has led to the development of in-season training interventions (21).…”