Comparison of Dominant and Non-Dominant Side Muscle Strength Asymmetry in Sarcopenic and Non-Sarcopenic Older Adults

Sarcopenia is a clinical condition in elderly individuals where muscle strength, muscle mass, and physical performance decrease, negatively impacting their quality of life. The European Working Group on Sarcopenia in Older People (EWGSOP) has developed a simple clinical definition and diagnostic criteria for age-related sarcopenia (1). Measurements of walking speed, grip strength, and muscle mass are taken to detect sarcopenia. The severity of the disease is It is measured by physical performance (1). Unilateral measurements in hand grip strength measurement used in diagnosis may lead to the neglect of muscle symmetry. Hand grip strength asymmetry (difference between dominant and non-dominant hands) has recently been evaluated as a sarcopenia risk indicator (2). Jedd Pratt et al. demonstrated a significant association between handgrip strength asymmetry (> 10% difference) and sarcopenia; they reported that asymmetric individuals have a 2.67-fold increased risk of sarcopenia and that this strategy has diagnostic power (2). In addition, it has been shown that the dominant side has greater strength and muscle mass in the upper extremities; however, this difference decreases with age (2). Huang et al. confirmed the relationship between handgrip strength asymmetry and muscle mass, showing that asymmetric individuals are more likely to have low muscle mass (3). In the lower extremities, quadriceps strength was found to have a clearer relationship with health outcomes (4). In the ISCOPE study, although the relationship between quadriceps strength and handgrip strength was limited, the combination of the two was found to be appropriate in defining the fragile group (4). In light of these studies, it can be suggested that dominant-non-dominant muscle strength asymmetry (upper and lower extremities) is greater in sarcopenic individuals and that this asymmetry parameter may have a guiding value in diagnosis. In the current literature, there is no study that evaluates asymmetries between biceps, quadriceps, and handgrip strength together and compares their predictive power specific to sarcopenia. This study aims to compare the differences in dominant-non-dominant biceps, quadriceps, and handgrip strength in sarcopenic and non-sarcopenic elderly individuals, and to examine its potential value as a novel biomarker in the diagnosis of sarcopenia.