Should the 30-Second Chair Stand Test Be Considered a Muscle Function Assessment?

Screening for age-related disease and disability is critical for proper diagnosis and management of a condition (1). The disabling process, for example, often consists of successive deficits in 1) muscle function, 2) physical performance, and 3) physical functioning during aging. Muscle function is generally characterized by strength, endurance, and power. Objectively measured whole body tasks related to mobility such as gait speed and the short physical performance battery are used to examine physical performance. Persons with poor physical functioning often have problems completing basic self-care tasks and are also at an elevated risk for age-related morbidities such as sarcopenia (2). Given that muscle dysfunction represents the onset and potential progression of the disabling process (2, 3), routinely examining muscle function in clinical settings will allow for the early intervention of age-related disease and disability, which in turn, may increase intervention efficacy and more quickly decelerate disablement. Strength, endurance, and power have been constantly identified as hallmark characteristics of musculoskeletal fitness that have widespread health benefits across the lifespan (4). Handgrip strength is a well utilized assessment of muscle function in clinical settings, but handgrip strength measurements are inconsistently included in routine geriatric clinical practice and have known limitations (5). For example, the generalizability of handgrip strength alone for being representative of overall muscle function is lacking because handgrip strength does not directly account for lower extremity functioning. Moreover, only strength capacity is being evaluated during handgrip strength assessments, and other aspects of muscle function such as endurance and power are not ascertained (5). However, alternative muscle function assessments that account for both lower extremity function and additional muscle function aspects are not feasible. Procedures for examining muscle endurance with handgrip dynamometry are not yet well established (5). Further, knee extension power measurements require expensive equipment and complex protocols that are mostly invasive for older adults (2). Therefore, continuing to examine how we can feasibly and accurately assess muscle function in clinical practice is crucial for precision in geriatric screenings and appropriate referrals. The 30-second chair stand test is a measure of lower extremity power and endurance (2). Similar to the gait speed test, the chair stand test can be both conducted as a standalone assessment or as part of the short physical performance battery (2). Equipment for conducting the chair stand test as a stand-alone assessment requires a straight back chair without arm rests and a stopwatch, and the number of total sit-standsit cycles are counted over 30-seconds (2). The 30-second chair stand protocol differs from that used in the short physical performance battery, such that the time to complete five sitstand-sit cycles is instead recorded (2). Additional evaluations such as coronal plane angle can also be adopted in chair stand tests (6). Although gait speed is a commonly used physical performance assessment (2), chair stands as an individual assessment are likewise predictive of adverse health outcomes (7-9).