CaReMoOC: Capacity, Reserve, Movement Objectives, and Compensation. A New Framework to Describe Mechanisms of Movement Limitations, Demonstrated for Ageing

To prevent, mitigate and treat movement impairments, we need to recognize early signs of decline and understand how to best compensate for limitations. The mechanisms leading to movement impairments are complex, overlapping, and interdependent and the fields of biomechanics, motor control, and physiology must be combined to understand these mechanisms. This article introduces CaReMoOC, a framework incorporating neuromusculoskeletal capacity (accumulation of neuromusculoskeletal resources over the lifespan), reserve (task-specific difference between capacity and task demand), movement objectives (considerations made to plan a movement), and compensation (use of NMSK resources to respond to the task demand). The framework is demonstrated for healthy ageing, providing an overview of age-related capacity decline (neural, skeletal, muscular system) and shifted weighting of movement objectives (energy, pain, stability, speed) relevant for biomechanics and motor control. Two forms of compensation are Compensation for Capacity, when capacity does not meet the task demands, and Compensation for Movement Objectives, when the movement is changed due to for example a fear of falling. Understanding the interrelationships between decline in the variables within capacity and the effect on compensation strategies will provide benefit in preventing mobility impairments and will support clinicians in their rehabilitation practice.