Quantification of High-Intensity Change of Directions and Single-Leg Decelerations Between Limbs Within Elite Youth...

Soccer requires repeated changes of direction (COD) and single-leg decelerations (SLD), which accrue considerable mechanical stress on the lower limbs. These actions place significant demands on the players' musculoskeletal system. An uneven utilization of these actions between limbs, arising from disparities in neuromuscular control and skill acquisition, may lead to asymmetries and increased injury risk. This study aimed to examine the effects of player position and footedness on the frequency of intense CODs, SLDs, and the total sum of the 2 actions (TOT) performed by the dominant and nondominant foot in elite male youth soccer players.

Twenty-five elite English youth soccer players were grouped by their playing positions (lateral: full-backs and wide midfielders; central: center defenders, center midfielders, and strikers) and footedness (left or right footed). High-intensity CODs and SLDs were identified using video analysis and GPS data across 6 matches. The frequency and distribution of these actions were analyzed to assess the impact of player position and limb dominance.

No significant differences were found in the percentage distribution of SLDs or TOT between the central and lateral groups. However, central players exhibited a significantly greater imbalance in COD frequency compared with lateral players (51.8% [31.5%] vs 29.9% [31.1%]; P < .05; d = 0.70). Players performed more CODs in the direction opposite to their dominant limb, indicating a preference for using the dominant limb as the plant limb (4.6 [3.2] vs 3.7 [2.6]; P < .05; d = 0.31).

The study highlights the mechanical and positional demands placed on soccer players, with central players showing greater COD frequency asymmetry.