Relative Intensities and Compositions of Multifactorial Peak Kinematic and Mechanical Demands in Elite Youth Soccer

Farzad Yousefian^1,2*Abdullah Zafar³Fábio Yuzo Nakamura^4,5Pedro Menezes⁶João Brito^2,7Bruno Travassos^1,2

• ¹Research Center in Sports Sciences, Health Sciences and Human Development (CIDESD); Department of Sports Sciences, University of Beira Interior, Covilhã, Portugal
• ²Portugal Football School, Portuguese Football Federation, Oeiras, Portugal
• ³Department of Biomedical Sciences, Montreal University, Montreal, Quebec, Canada
• ⁴Department of Sports Sciences and Physical Education, University of Maia, Maia, Portugal
• ⁵Research Centre in Sports Sciences, Health Sciences and Human Development (CIDESD), University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
• ⁶Clube de Regatas do Flamengo, Rio de Janeiro, Brazil
• ⁷Interdisciplinary Center for Human Performance, Faculty of Human Motricity, University of Lisbon, Dafundo, Portugal

Background: Characterizing the most demanding passages (MDP) of physical activity during soccer competition is essential for optimizing training prescription and player monitoring. However, research investigating kinematic and mechanical MDP using a multifactorial criterion variable approach in elite youth soccer players remains limited. This study examined the relative intensities and compositional structure of multifactorial kinematic and mechanical MDP across different durations in an elite youth international tournament. Methods: Locomotor activity data were collected from 17 elite youth players across five matches of an international tournament using GPS technology. Kinematic and mechanical MDP were identified using multifactorial criterion variables: MDPk (kinematic) and MDPm (mechanical). Linear mixed models assessed relative intensities (m•min⁻¹ or efforts•min⁻¹) and the univariate constituent compositions of MDPk (moderate-speed running [MSR], high-speed running [HSR], sprinting [SPR]) and MDPm (high-intensity accelerations [ACC3], decelerations [DEC3]) across rolling (R') 1-, 3-, and 5-minute durations, comparing matches and positional groups (central, lateral).Results: Differences between matches and positions were observed only for R1' MDPk intensities. Both MDPk and MDPm intensities decreased as duration increased. Betweenmatch differences were observed for MDPk composition, particularly for %HSR and %SPR. MDPk composition was duration-dependent, as %HSR and %SPR were greater in R1' than R3' and R5', while %MSR followed the opposite trend. In contrast, MDPm composition remained stable across durations.Conclusions: Practitioners should consider both the relative intensities and compositional structures of MDPk and MDPm when evaluating multifactorial peak demands in soccer. Analyzing kinematic and mechanical MDP as multivariate constructs offers essential insight into the contribution of specific locomotor demands across various durations. This approach underscores the need for duration-specific analyses to optimize training, recovery, and match preparation strategies, thereby facilitating targeted training interventions and enhancing player readiness for competition.