Validity and reliability of a smartphone-based assessment for anticipatory and compensatory postural adjustments during predictable perturbations

Postural adjustments involve displacements of the center of mass (COM), controlled by the central nervous system (CNS), to maintain equilibrium whilst standing. Postural adjustments can be anticipatory (APAs) or compensatory (CPAs), and are triggered to counteract predictable perturbations. Is the new smartphone application, Momentum, a valid and reliable tool for the assessment of body balance, by measuring APAs and CPAs using accelerometer readings? 20 young adults were exposed to external predictable perturbations induced at the shoulder level, whilst standing. COM linear acceleration was recorded by Momentum (extracting data from a smartphone’s accelerometer) and a 3D motion capture system. The key results demonstrated a very high, significant correlation (r ≥ 0.7, p