Chasing Symmetry: Inter-limb Imbalances & Performance in Youth Tennis
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- Background & Objective
- What They Did
- What They Found
- Practical Takeaways
- Reviewer’s Comments
- About the Reviewer
Madruga-Parera, Marc1,2; Bishop, Chris3; Fort-Vanmeerhaeghe, Azahara4; Beltran-Valls, Maria R.2,5; Skok, Oliver G.6; Romero-Rodríguez, Daniel1 Interlimb Asymmetries in Youth Tennis Players: Relationships With Performance, Journal of Strength and Conditioning Research: October 2020 – Volume 34 – Issue 10 – p 2815-2823 doi: 10.1519/JSC.0000000000003152
Click here for abstract
Background & Objective
Tennis, by nature, is a multidirectional sport that requires individuals to perform numerous unilateral movements. For example, 70% of movements that occur on a tennis court occur from a lateral position (see HERE). Therefore, a difference in function or performance between limbs (i.e. interlimb asymmetries) can have significant effects on an individual’s ability to perform optimally.
The objective of this study was to investigate the asymmetries present in young tennis players during a fitness testing battery.
What They Did
Twenty-two elite youth tennis players (16.3 yr) were tested over two days that were separated by a 72h rest period, with each players’ training load decreased by 50% during the testing period to support testing performance. Day 1 consisted of three unilateral jump tests (countermovement jump (CMJ), broad jump, and lateral jump) and a 180-degree turn change of direction (CoD) test. On the second day, players performed a CoD task (shuffle and crossover step) that was resisted by an isointertial device (Byomedic System SCP).
All subjects performed three practice trials for all tests and a specific warm-up prior to testing, which consisted of 5-min of light jogging, dynamic stretches, and lower-body strength exercises (lunges, inchworms, and bodyweight squats).
What They Found
“This study provides practitioners with a guide to test lower-limb asymmetries. Monitoring of inter-limb asymmetry is important, as athletes who show higher levels of asymmetry (>15%) between-limb difference are at a greater risk of lower- limb injury. Furthermore, although limb dominance is relatively normal, reductions in jump height and CoD performance have also been previously reported (see HERE) when a large imbalance is present. This will be detrimental to tennis performance, so ensuring that these are monitored is important.
A limitation of this study though, is that the participants’ stage of maturation was not considered. In the attached article, Madruga-Parera and colleagues reported that higher levels of asymmetry were present circa-peak height velocity than those who were pre-/post-peak height velocity. The authors attribute this to a temporary loss in motor control, commonly known as “adolescent awkwardness”, which occurs during PHV and results in compromised physical outputs. Future studies must consider this in a youth cohort to ensure data validity. Finally, both CoD tests were poor at revealing asymmetries. Jump testing may be a more time-effective and reliable test to measure inter-limb asymmetries.”
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