Quantifying Muscle Recovery: A Scoping Review of Existing Markers and Measurement Approaches

Introduction. Muscle recovery is a critical factor in optimizing athletic performance, as well as in clinical and rehabilitation settings. A range of biochemical markers, functional, and perceptual measures are used to assess both exercise-induced muscle damage (EIMD) and delayed onset muscle soreness (DOMS). This scoping review aims to evaluate the applicability of these assessment methods by examining their cost, complexity, accessibility, accuracy, and degree of innovation. Material and Methods. A total of 1,324 articles were identified using relevant keywords during an initial search in Web of Science (n = 616) and Scopus (n = 698) databases. No strict quality assessment protocol was applied as the present study focused on emerging EIMD markers, sample size adequacy, relevance, and methodological clarity. After removing duplicates and applying strict inclusion and exclusion criteria, 34 articles were selected for detailed analysis. Results. While subjective measures are simple and non-invasive, their lack of accuracy limits their effectiveness. Biochemical markers such as creatine kinase, C-reactive protein, and cytokines provide precision but are costly and often impractical in low-resource settings. Imaging and molecular techniques deliver high accuracy but involve complex, laboratory-based procedures. Functional tests like counter movement jumps, limb circumference measurements, and pain pressure threshold offer a balance between cost and applicability. Conclusions. The review indicates that the subjective measures such as visual analogue scale and functional test like counter movement jump, limb circumferences and pain pressure threshold are ideal methods for EIMD assessment with some limitations. The review also emphasizes the need for innovative approaches to EIMD quantification.