A comprehensive understanding of skill acquisition is important for different performance domains, and has practical implications for both sport sciences and public health. The study compared important constraints for expertise development in a physically demanding sport (cross-country skiing) versus a technically demanding sport (freeskiing). Eighteen world-class athletes reported the importance of different constraints for their developmental history subdivided into two age spans: (1) 7–15 years and (2) 16 years until present. The total amount of training did not differ between the groups, but from the age of 16, the cross-country skiers spend approximately 98% of their training specific to their main sport, compared to 75% for freeskiers. No differences were found between the distribution of organized versus non-organized training in main sport, but freeskiers reported a higher amount of unorganized training in other sports after the age of 16. No differences were found in perceived importance of facilities, enjoyment of performing their sport, or the need for early specialization of training. After the age of 16, the cross-country skiers reported a higher need for coach involvement compared to freeskiers. The two sports mainly share common paths to expertise but differ in the need for specific training and coach involvement.

Different characteristics of sports disciplines potentially lead to skewness in birth month distribution (relative age effect, RAE). These characteristics can be considered from a constraint-based approach with interacting environmental, task, and individual constraints as a theoretical framework with which to examine variations in RAE. The main aim of the present study was to examine the theoretical predictions of the constraint-based framework by investigating the birth month distribution in cross-country skiers and freeskiers at elite junior and senior levels. The sample was comprised of top ranked Norwegian U15–U19/20 cross-country skiers and junior-level freeskiers. Birth months of top ranked international senior-level skiers in cross-country and freeskiing were also collected. Results indicated an over-representation of skiers born in the first half versus the second half of the year at all junior ages in cross-country skiing. There was no significant difference in the distribution of birth months in freeskiing or in senior cross-country skiers or freeskiers. Based upon the interacting constraint framework, the skewness towards more early-born athletes in junior cross-country skiing could be due to strict age-grouped and results-oriented developmental programs beginning at an early age (environmental constraints) as well as high-demand for physical capabilities (task constraints) that favour more physically mature athletes (individual constraints). For freeskiing, the interacting environmental (less structured and more individualistic-oriented development), task (high technical/motor skill demands), and individual (no advantage of advanced physical maturation) constraints potentially operate in the opposite direction compared to cross-country skiing.

Introduction: This study examined longitudinal trends in attacking play and goal-scoring patterns among top-performing men’s and women’s teams in elite international handball. Methods: Match performance data were analysed from 666 matches across 10 European Handball Federation EURO Championships (five men’s and five women’s tournaments) conducted between 2016 and 2024. Results: The findings revealed a consistent increase in the contribution of positional attacks to goal scoring across both men’s and women’s competitions. This was accompanied by marked increases in 6-m finishes and breakthrough goals. In contrast, fast-break scoring remained stable or showed a slight decline over time, suggesting a growing emphasis on structured offensive play against increasingly organised defensive systems. Spatial analyses indicated a progressive centralisation of scoring activity towards close-range zones, while wing and 9-m shooting exhibited more variable or declining patterns across tournaments. Gender-based comparisons indicated that men produced higher outputs in several structured attack categories, whereas no meaningful gender differences were observed in transitional or numerical imbalance situations. Discussion: These findings indicate a systematic shift in the offensive ecology of elite championship handball towards centrally organised, high-probability scoring actions. Implications are discussed through the lens of representative learning design, highlighting how empirically derived match patterns can inform the design of representative practice tasks that preserve key perceptual–temporal constraints of competition. By aligning training environments with stable performance regularities observed at the highest level, coaches can better support functional decision-making and transfer from training to match play within comparable elite contexts.

Skill learning is often discussed in terms of closely related but insufficiently integrated concepts: challenge, instructional methods, discovery, self-regulation, specificity, retention, and transfer. As a result, practice design is frequently reduced to either adjusting task difficulty or prescribing movement solutions more explicitly. Compounding this, learning is routinely inferred from immediate performance quality, even though performance and learning unfold on different timescales and across qualitatively distinct contexts. This Perspective article advances a different view: skill learning is best understood as the progressive differentiation and calibration of affordance relations under functionally representative constraints. On this view, challenge is not a fixed property of tasks but a learner-relative, information-generating relation among the learner, the task, and the performance context. Discovery is the exploratory process through which learners search, differentiate, tune, and stabilize affordance relations. Self-regulation is the recursive process through which learners define tasks, monitor consequences, sustain motivation, and adapt their actions over time. Specificity is reframed through representative learning design, where the critical requirement is not superficial resemblance or high-fidelity mimicry but functional equivalence between practice and performance: the preservation of the affordances, timing demands, and constraints that regulate skilled activity. Improvement, in turn, is judged not by immediate performance gains alone but by retention, transfer, adaptability, and the development of self-regulatory capacity. Together, these claims reposition challenge, discovery, self-regulation, and representative learning design as interdependent elements of a single learning-design problem. The reframing carries direct implications for how improvement should be defined and evaluated, and for how practitioners across physical education, sport, coaching, and therapy might design conditions for durable, transferable, and adaptive skill.