Abstract
The prevention, mitigation and treatment of movement impairments, ideally, requires early diagnosis or identification. As the human movement system has physiological and functional redundancy, movement limitations do not promptly arise at the onset of physical decline. A such, prediction of movement limitations is complex: it is unclear how much decline can be tolerated before movement limitations start. Currently, the term ‘homeostatic reserve’ or ‘physiological reserve’ is used to refer to the redundancy of the human biological system, but these terms do not describe the redundancy in the muscle architecture of the human body. The result of functional redundancy is compensation. Although compensation is an early predictor of movement limitations, clear definitions are lacking and the topic is underexposed in literature. The aim of this article is to provide a definition of compensation and emphasize its importance. Compensation is defined as an alteration in the movement trajectory and/or altering muscle recruitment to complete a movement task. Compensation for capacity is the result of a lack in neuromusculoskeletal reserve, where reserve is defined as the difference between the capacity (physiological abilities of the neuromusculoskeletal system) and the task demand. Compensation for movement objectives is a result of a shift in weighting of movement objectives, reflecting changing priorities. Studying compensation in biomechanics requires altered protocols in experimental set-ups, musculoskeletal models that are not reliant on prescribed movement, and inclusion of alternative movement objectives in optimal control theory.
Highlights
By 2050, all regions except for Africa will have at least 25% of their population over 60 years old and the proportion of people aged 80 or over will have tripled by that time (UN 2019)
While the fields of biomechanics and motor control seek to understand the mechanisms of age-related mobility decline by understanding dynamics and control of biological systems, the field of physiology focusses on the biological processes
Definitions and terminology on compensation as a result of functional redundancy are lacking and we feel that the topic is underexposed in literature
Summary
By 2050, all regions except for Africa will have at least 25% of their population over 60 years old and the proportion of people aged 80 or over will have tripled by that time (UN 2019). The biological redundancy available to compensate for age and disease-related changes has been referred to as the ‘homeostatic reserve’ or ‘physiological reserve’ (Clegg et al 2013) These terms do not incorporate the redundancy in the muscle architecture of the human body, the functional redundancy Terms such as ‘physiological capacity’ (Oseid 1973), ‘musculoskeletal reserve’ (Bull, Cleather, and Southgate 2008), and ‘musculoskeletal capacity’ (Nygård et al 1987) have been used, but a general understanding and definition of these terms in the fields of biomechanics and motor control is lacking. Definitions and terminology on compensation as a result of functional redundancy are lacking and we feel that the topic is underexposed in literature In this short communication we propose definitions on compensation and emphasize the importance of including compensation in (age-related) biomechanics research
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
