The aim of this study was to determine the effect of muscular strength, strength asymmetries, and fatigue on the speed and accuracy of an instep kick in soccer players. We measured ball velocity (BV) and kicking accuracy (KA) in the preferred (PL) and non-preferred leg (NPL) before (PRE) and after (POST) physical load in the PL. Maximum peak muscle torque of the knee extensors and flexors in the PL and NPL as well as ipsilateral knee flexors and knee extensors ratio (H:Q ratio) for both legs were assessed. BV was significantly decreased in POST physical load (5.82%, BVPRE=30.79±1.70 m·s-1, BVPOST=29.00±1.70 m·s-1, t19=3.67, p=0.00, d=1.05). Instep kick accuracy after the physical load worsened by an average of 10% in the most accurate trials. Results revealed a significant decrease in instep kick accuracy after physical loading (KAPRE=2.74±0.70 m, KAPOST=3.85±1.24 m, t19=-3.31, p=0.00, d=1.10). We found an insignificant correlation between H:Q ratio and KA in PRE test value, whereas a lower ipsilateral ratio (higher degree of strength asymmetry) in the POST physical load significantly correlated with KA in all angular velocities (r=-0.63 up to -0.67, p=0.00).

Division of Sports Medicine Department of Orthopedics Boston Children's Hospital Boston MA USA

Faculty of Physical Education and sports Charles University Prague Prague Czech Republic

Harvard Medical School Boston MA USA

The Micheli Center for Sports Injury Prevention Waltham MA USA

References provided by Crossref.org

Relationships of lower extremity and trunk asymmetries in elite soccer players

Characteristics of external loads of Hockey5s associated with the new version of U16 youth field hockey competition

Elite young soccer players have smaller inter-limb asymmetry and better body composition than non-elite players

Isokinetic Strength, Vertical Jump Performance, and Strength Differences in First Line Professional Firefighters Competing in Fire Sport

Unilateral and Bilateral Strength Asymmetry among Young Elite Athletes of Various Sports

Effect of a Simulated Match on Lower Limb Neuromuscular Performance in Youth Footballers-A Two Year Longitudinal Study

Anthropometric, Body Composition, and Morphological Lower Limb Asymmetries in Elite Soccer Players: A Prospective Cohort Study

Morphological and Isokinetic Strength Differences: Bilateral and Ipsilateral Variation by Different Sport Activity

Physical Fitness Characteristics of High-level Youth Football Players: Influence of Playing Position

Foot typology, body weight distribution, and postural stability of adolescent elite soccer players: A 3-year longitudinal study