Development and content validation of a micro-structure framework for swim training: A Delphi study

Traditional approaches to talent development in swimming have emphasised cumulative training volume and early specialisation as primary determinants of elite performance. However, growing evidence suggests that these metrics alone provide only a partial explanation of high-level achievement, underscoring the need to examine how training is experienced, not only quantified. Within the ecological dynamics framework, fourteen dimensions of the micro-structure of practice have been proposed to describe how athletes functionally interact with task, environmental, and personal constraints through aspects such as supervision, instruction, intensity, effort, variability, specificity, and enjoyment. This study aimed to develop and establish the content validity of a questionnaire assessing swimmers’ perceptions of these fourteen micro-structural dimensions. A four-round Delphi study (n = 21, 16, 16, 15) was conducted with international experts using an ≥80% consensus threshold. Twelve dimensions were validated; physical effort was merged with intensity, and playfulness was excluded. Traditional load-related dimensions reached rapid consensus, whereas more conceptually nuanced dimensions required additional refinement. The final instrument operationalises the micro-structure of practice into measurable perceptual constructs, providing a concise means of characterising training environments and supporting ecologically grounded athlete development. It enables coaches and researchers to examine and shape training environments beyond traditional structural metrics.