Muscle amnesia: a hypothesized framework for motor-pattern accessibility in exercise rehabilitation after inactivity, injury and illness

After inactivity, injury or illness, people may regain part of their strength, range of motion or load tolerance before they recover fluent movement. Clinicians may observe an athlete, patient or older adult who can generate force but returns to walking, squatting, standing, running or sport with a guarded, variable or inefficient movement strategy that appears disproportionate to remaining impairment. This Perspective presents a theoretical framework and proposes the term Muscle Amnesia as a cautious practical label for a history-, use- and context-sensitive reduction in access to a previously acquired task solution. The term is not intended to imply literal memory loss within muscle tissue, to replace established concepts or to create a new diagnosis. Rather, it names a candidate clinical-behavioural construct in which altered exposure, compensatory practice, pain, threat, fatigue, context change and reduced task practice may shift motor-pattern selection. The aim of this article is to define the construct, distinguish it from detraining, learned non-use, pain-adapted movement, skill decay and maladaptive compensation, and propose preliminary candidate criteria and research designs. We argue that exercise rehabilitation should examine not only physical capacity, but also whether capacity is organized into task-relevant movement. The framework remains hypothetical and requires qualitative, experimental and clinical validation.