Mathew Piasecki

1 Introduction The loss of motor units (MUs) occurring in neurogenic diseases [1-3] is normally accompanied by the expansion of individual motor units (MU remodeling) [4, 5]. The electromyography (EMG) interference pattern recorded by needle electrodes is a widespread tool to study MU loss [6]. The reduction in MU numbers can be qualitatively assessed by observing the “fullness” of the EMG interference pattern recorded at maximal effort [7].

Experimental approaches to physiological disuse have primarily explored underlying mechanisms of reduced neuromuscular function and muscle mass. These studies have translational implications for clinical settings, spaceflight and, in some instances, are used as a model of accelerated ageing (Deane et al., 2024).

Introduction Skeletal muscle is the largest organ in the human body, comprising ~40% of whole-body mass in healthy adults.1 Crucial for many functions associated with whole-body health beyond its most recognized role in locomotion, skeletal muscle also plays a fundamental role in energy homeostasis, oxygen consumption, energy metabolism, and substrate turnover and storage.2 A highly plastic tissue, skeletal muscle mass is maintained in health via a dynamic equilibrium between muscle protein...