Functional performance and interlimb asymmetries of young football players during single-leg jump tests

Abstract

Background Jumps are predominant components in football (soccer). Interlimb functional difference in single-leg jump performance is a risk factor for lower extremities injuries. Screening uninjured athletes is essential to design prevention strategies and implement individual training interventions. The aims of this cross-sectional study were (1) to provide age-specific mean values and limb symmetry index (LSI) in young football players, (2) to detect age effect on LSI and interlimb functional differences and (3) to investigate the association of age with single-leg functional performance and LSI. Methods A total of 146 male football players (age 14.2 ± 2.3) performed the countermovement jump, jump for distance, side hop and speedy jump tests. Descriptive statistics, mean values (dominant/non-dominant) and LSI were provided according to age groups (U11–U19). Two-way mixed analysis of variance (ANOVA), one-way ANOVA and Pearson’s correlation were used for the statistical analysis. Results Participants showed on average perfect LSI (103.8 ± 14.2%) amongst all tests and age groups. Interlimb functional differences occurred in three out of four tests (p < 0.05), without age interaction (p > 0.05). Age effect was positively associated with single-leg functional performance (p < 0.05), but not with LSI (p > 0.05), in all tests and age groups. Conclusion An LSI ≥100% in single-leg jump tests is proposed as a benchmark in young football players, but interlimb performance differences may occur without age interaction. Nevertheless, the growth process plays a crucial role in the development of functional capacities: older players may show a higher single-leg jump performance, but not a higher LSI, than younger players. In football practice, preventive intervention is advisable to counteract interlimb performance differences, for which unilateral strength, power and plyometric training is recommended.

Bilateral Asymmetry and the Relationship Between Unilateral Isokinetic Strength and Balance Performance in Male Adolescent Football Players

“…However, LSI ranged between 98.3% and 98.8%, indicating the existence of small bilateral asymmetries. Previous research reported an average LSI of 103.8% among players between the U11 and U19 age categories when the jump performance was evaluated (Scinicarelli et al, 2022). Still, only one study examining bilateral asymmetry using isokinetic strength was found in youth football, with mean differences of nearly 8% being described at an angular velocity of 60º/s (Rutkowska-Kucharska, 2020).…”

A Single-Leg Vertical Hop Test Is an Effective Tool to Measure Functional Performance after Anterior Cruciate Ligament (ACL) Reconstruction

“…In addition to the SLVHT, a single-leg hop test for distance was performed by the patients six months postoperatively as described elsewhere [19]. All patients were asked to complete the International Knee Documentation Committee subjective knee form (IKDC SKF) [14] and the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaires [30,31] at six months postoperatively.…”

“…The single-leg vertical hop test (SLVHT) has been recommended as a measure of functional performance due to its safety and feasibility and the possibility of implementation during early rehabilitation [17,18]. The performance in vertical hop tests is usually quantified by video analysis (elevation of the centre of the body, e.g., pelvic bone) or by contact mats [17,19,20]. However, these methods are time-consuming, person-dependent, and material-and cost-intensive [17].…”

Unilateral and bilateral jumping performance in female basketball players with and without a history of lower limb injuries

“…To determine this, the ratio between the scores of the dominant and non-dominant limbs is calculated. Many athletes, whether professional or amateur, tend to favour one leg during training or competition, which can lead to a noticeable difference in muscular strength between their dominant and non-dominant legs over time [6]. However, the role of asymmetries as risk factors for future injuries still needs to be established, as previous studies have provided limited evidence [5,7].…”