Landings: Implications for performance

Abstract

Landings performed in the context of everyday activities are a fundamental component of human movement and occur under a variety of circumstances. Successful landing performance depends on the ongoing interaction between the neuromuscular and musculoskeletal systems prior to and during contact with the landing surface. Because landings performed in different contexts can have considerably different mechanical objectives, advancement of our understanding of the control and dynamics during landings benefits from investigation of landings under diverse conditions. By clarifying the mechanical objectives to be achieved in each phase of the landing, the unique challenges imposed on the individual can be compared across different tasks. Our aim is to explore the multijoint control strategies used to satisfy varying landing task objectives at the whole body level and to address the mechanical demand imposed on the individual during the impact and postimpact phases of different landings. Specifically, we aim to demonstrate how the orientation of the reaction force relative to lower extremity body segments influences the distribution of mechanical demand across the lower extremity joints. By analyzing the relative contribution of the ankle, knee, and hip to the lower extremity control, we highlight the interdependence of these joints in controlling the lower extremity subsystem and provide important rationale for how uni- and biarticular muscles can work together to generate lower extremity net joint moments needed to control the limb at an instant. Evidence from both experimental and model simulation studies is included to provide insight regarding the ongoing interaction between the nervous and musculoskeletal systems during contact with landing surfaces under a range of conditions. Identifying how individuals satisfy the mechanical objectives of landings performed under realistic conditions provides important context for understanding landing performance. When integrated together, these results provide valuable insight on how to prepare an individual for successful landing performance under conditions that they are likely to encounter as part of their everyday activities.