Flexible reconfiguration of variability structures between multiple solution manifolds in skilled soccer athletes' throw-ins

Abstract

Skilled performers can produce highly consistent outcomes despite substantial variability within the motor control system. Previous studies have demonstrated that such consistency is achieved by structuring variability in execution variables so that it lies within the solution manifold. In this study, we extended this framework from conventional single-distance tasks with a fixed solution manifold to multiple-target conditions, and examined how athletes reconfigure variability in execution variables when the solution manifold changes shape across task demands. Ten male collegiate soccer athletes performed randomized, no-run-up throw-ins to targets at 10–90% of their individual maximum projection distance. Distance-specific solution manifolds were derived, and valid throws were classified as either the Task Tolerance strategy, which exploits regions of the solution manifold where variability in specific execution variables has little effect on the outcome, or a Covariant Structure strategy, which relies on compensatory covariation across execution variables. Participants adjusted projection distance reliably, and strategy use changed systematically with distance: the Covariant Structure strategy predominated at 20–40%, whereas the use of the Task Tolerance strategy increased sharply at 50–80% (Friedman p < .001). These results show that skilled throwers maintained broadly stable projection-distance variability even when task constraints changed and the underlying solution manifold took on different shapes. At the same time, the systematic shift in strategy use suggests distance-dependent reorganization of variability structures across distance-specific solution manifolds.