Relative Age, Maturation and Physical Biases on Position Allocation in Elite-Youth Soccer.

This study assessed the contribution of relative age, anthropometry, maturation, and physical fitness characteristics on soccer playing position (goalkeeper [GK], central-defender [CD], lateral-defender [LD], central-midfield [CM], lateral-midfielder [LM], and forward [FWD]) for 465 elite-youth players (U13-U18's). U13-14 CD were relatively older than LD and CM (likely small effects). CD and GK were generally taller and heavier (likely small to very-likely moderate effects) than other players at each developmental stage and were advanced maturers at U13-14 (very-likely small to likely moderate effects). GK had inferior agility (very-likely small to likely moderate effects), endurance (very-likely small to likely moderate effects), and sprint capacities (likely small-moderate effects) vs. outfield positions at U13-14, but deficits in anaerobic phenotypes were diminished in U15-16 and U17-18. Position specific fitness characteristics were distinguished at U15-16 (likely small) and U17-18 (likely moderate), where LM were faster than their central counterparts. In summary, relative age, maturation and anthropometric characteristics appear to bias the allocation of players into key defensive roles from an early development stage, whereas position-specific physical attributes do not become apparent until the latter stages of talent development in outfield players. Given the inter-individual trajectories of physical development according to biological maturation, playing position allocation might be considered 'plastic' by selectors, until complete-maturity is achieved.

Muscle-damaging exercise 48 h prior to a maximal incremental exercise treadmill test reduces time to exhaustion: is it time to reconsider our pretest procedures?

Pretest guidelines typically stipulate that no exercise should be performed 48 h prior to a maximal incremental exercise [Formula: see text] test. However, no study has specifically investigated if this timescale alters key outcome variables associated with [Formula: see text]. Twenty apparently healthy males split into two equal groups performed [Formula: see text] during three visits (visits 1 - [Formula: see text]EXP1, 2 - [Formula: see text]EXP2 and 4 - [Formula: see text]EXP3). The experimental group only, performed muscle-damaging exercise during visit 3. From [Formula: see text]EXP2 to [Formula: see text]EXP3 average time to exhaustion (TTE) decreased by 45 s (9%) (p < 0.01), maximum blood lactate decreased by 1.2 mmol/L (11%) (p = 0.03), and perceived readiness decreased by 8 mm (18%) (p = 0.01). There were no changes in any [Formula: see text] variables in the control group (p ≥ 0.37). Performing [Formula: see text] 48 h following muscle-damaging exercise impairs specific, but not all, physiological outcome variables.