Extracorporeal Shock Wave Therapy Combined with Subtalar Arthroereisis and Medial Column Stabilisation in the Treatment of PCFD: A Retrospective Study.

Musculoskeletal injury is a primary determinant of athlete availability, performance development, and long-term participation in collegiate and emerging-adult sport (). Adolescent and emerging-adult cohorts in particular show high injury burden during competitive seasons, with overuse and lower-extremity injuries dominating epidemiological surveys (, ). Annual age-grouping with a fixed cut-off date is the structural backbone of nearly every sport pathway worldwide, and this practice produces the relative age effect (RAE): the systematic overrepresentation of athletes born early in the selection year relative to their later-born peers (, ). Whether selection-related birthdate asymmetry intersects with objectively assessed musculoskeletal risk in the athletes who survive into pathway-level competition is a question of direct relevance to both talent-identification practice and athlete welfare. Despite four decades of RAE research and a parallel surge in AI-augmented biomechanical screening, these two lines of evidence have developed independently and have rarely been brought into direct empirical dialogue (, ). The body of knowledge in relative age effects is now firmly established. Recent analyses spanning four decades of Ballon d'Or nominees, multi-sport Youth Olympic Games competitors, and Olympic karate athletes have consistently shown overrepresentation of relatively older athletes at every selection level (, , ). Female effects are typically smaller in magnitude but directionally similar to those reported in males (, ). The injury consequences of this asymmetry, however, remain contested. A cohort of 1,997 paediatric athletes reported significantly more injuries among relatively older children, a pattern attributed to early-maturing players carrying larger training loads (). In direct tension with this, a growing body of work supports an underdog or survivorship hypothesis as late-born athletes who reach elite levels represent a self-selected sub-population whose technical, tactical, and perceptual-cognitive attributes have compensated for an early maturity disadvantage (, ). Recent large-scale longitudinal evidence continues to support this survivorship reading: a 44-year analysis of 10,485 NHL-drafted players found that late-born athletes who overcame draft under-representation demonstrated significantly faster league entry and higher career permanence than their relatively older counterparts, consistent with compensation operating through non-physical selection pathways (). Qualitative systematic-review evidence further indicates that long-term individual performance is in fact more often associated with reversed RAE patterns than with the early-selection bias itself, although world-class track and field data show that the 1st quartile birth advantage can persist into adulthood in some events (, ). A recent study among Malaysian collegiate track and field athletes likewise found that RAE and injury prevalence co-occur in event-specific rather than uniformly graded ways (). However, whether such residual asymmetry is detectable in objective biomechanical indices rather than self-reported injury counts has not been examined. The theoretical mechanism by which RAE could translate into a detectable biomechanical signature operates through two well-established pathways: biological maturation and cumulative training exposure. A recent scoping review of elite youth pathway athletes established that maturity status is associated with increased injury incidence and burden, and that more rapid somatic growth links directly to greater injury susceptibility, particularly for lower-limb tissues (). Training load itself is the proximal determinant of tissue-level exposure and injury occurrence (, ). RAE selection could plausibly leave one of two competing biomechanical imprints on surviving athletes, since chronological age partially indexes biological maturity and training exposure accumulates differentially for early- and late-born athletes across the selection pathway. Under a cumulative-load account, late-born athletes at elite level would carry residual biomechanical risk from the prolonged compensatory training required to remain in the pathway. Under a survivorship account, late-born athletes reach elite level primarily through technical, tactical, and psychological compensation, and no biomechanical difference would be expected between quartiles. Empirical evidence favours the survivorship account: a 10-year retrospective analysis of an elite Scottish soccer academy found that anthropometric and physical performance variables did not reliably predict successful contract award despite a strong 1st quartile bias at recruitment, and academy-cohort work has directly linked late-maturity status to superior self-regulation skills consistent with non-physical compensation (, ). The two accounts therefore make directionally opposing, empirically testable predictions in surviving cohorts.