The chosen one: progression to elite professional football through physical performance and participation

Carpels, Thomas (2026) The chosen one: progression to elite professional football through physical performance and participation. PhD thesis, University of Glasgow.

Abstract

The transition from youth academy to elite professional soccer represents one of the most selective stages within player development pathways. Despite substantial investment in academy systems and the recent advances in performance monitoring and talent development research, the post-formation phase seems to remain insufficiently understood. While progression has traditionally been attributed to physical and physiological performance, emerging evidence suggests that opportunity and contextual factors also play a critical role. Existing research has predominantly examined isolated components of player development (e.g. physical performance, load monitoring, and talent identification), yet an attempt for an integrated investigation of how structural opportunity, physical readiness, match utilisation, and training exposure interact to influence progression is currently still missing. Therefore, the overarching aim of this thesis was to investigate talent development during the post-formation phase in elite professional soccer by examining the structural, physical, and performance-related factors influencing progression from late-stage academy environments to sustained first-team participation.
This thesis started off by establishing whether or not there truly is a bottleneck in the youth-to-senior transition. Are talented young academy players really offered limited opportunities to progress to the first team compared to newly signed players from outside the club? To answer this question, study 1 examined structural opportunity by analysing longitudinal demographic data across elite European soccer. The findings revealed that club-trained players represented a limited proportion of first-team squads and accumulated relatively low match involvement, with this trend decreasing over time. Interestingly though, a positive association was identified between club-trained player match involvement and team success, suggesting that the integration of academy players does not compromise competitive performance. These findings indicate that opportunity is shaped by organisational strategy rather than constrained by performance demands.
So, why are academy players given less opportunities to be part of a club's first team? Are their performance standards and capacity not up to par compared to their senior peers? Study 2 investigated physical readiness by comparing physiological characteristics and locomotor performance between academy/reserve and senior players within the same professional environment. The results showed that developmental players frequently demonstrated physical outputs comparable to senior players across key performance metrics. While minor differences were observed, these findings suggest that physical readiness alone does not explain progression outcomes and may function as a prerequisite rather than a distinguishing factor.
Study 3 explored match utilisation through the analysis of substitute performance. Players introduced during matches were capable of maintaining or increasing highintensity output, reinforcing the importance of high-intensity actions in match performance and outcome. Considering the physical comparability observed in Study 2, these findings suggest that physically prepared players may be capable of contributing effectively when provided with match opportunities. As such, an effective strategy of utilizing substitutions can not only increase intensity levels - which in turn can have a positive impact on match outcome - but also provide opportunities of meaningful exposure for academy players to express performance capacity and to gain valuable experience to support continuous development and sustained senior participation.
Finally, study 4 examined training exposure and load distribution across developmental and senior environments. The findings demonstrated clear differences in training structure, with academy environments emphasising overload and development, and senior environments prioritising recovery and performance maintenance. Additional discrepancies were observed between starting and nonstarting players, indicating variable and sometimes suboptimal load exposure. These differences suggest that players may transition into senior environments without consistent exposure to the specific demands of elite competition.
In conclusion, progression to elite professional soccer is not determined by physical performance alone. While physical readiness is necessary, it is insufficient in the absence of opportunity to participate and perform. Instead, progression may be shaped by the alignment between physical performance and participation within structurally constrained environments. These findings highlight the importance of integrating performance capacity with meaningful competitive exposure to support player development during the post-formation phase.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: R Medicine > RC Internal medicine > RC1200 Sports Medicine
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
• Supervisor's Name: Kemi, Dr. Ole
• Date of Award: 2026
• Depositing User: Theses Team
• Unique ID: glathesis:2026-86323
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 09 Nov 2026 15:42
• Last Modified: 09 Nov 2026 15:46
• Thesis DOI: 10.5525/gla.thesis.86323
• URI: https://theses.gla.ac.uk/id/eprint/86323

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