The 1-min sit-to-stand test induces a significant and reliable level of neuromuscular fatigability: insights from a mobile app analysis

The performance metric associated with the execution of the 1-min sit-to-stand (1STS) typically relies on the number repetitions completed in 1 min. This parameter presents certain limitations (e.g., ceiling effect, motivational factors) which can impede its interpretation. Introducing additional parameters, such as neuromuscular fatigability level, could enhance the informative value of the 1STS and facilitate its interpretation. This study aimed to assess (i) whether the 1STS induces fatigability and (ii) the reliability of the fatigability level.

Forty young, healthy, and active participants underwent the 1STS twice during the same session. Isolated sit-to-stand maneuvers were performed before, immediately, and 1 min after completing the 1STS. A mobile app was utilized to obtain time (STS_T), velocity (STS_V), and muscle power (STS_P) from these sit-to-stand maneuvers. The pre–post change in these parameters served as the fatigability marker. Reliability was assessed using the intra-class correlation coefficient (ICC) and the coefficient of variation (CV).

The mean number of repetitions during the 1STS was 63 ± 9. Significant decline in performance was observed for STS_T (13 ± 8%), STS_V (−11.2 ± 6%), and STS_P (−5.2 ± 3%), with more than 74% of participants exhibiting a decline beyond the minimal detectable change. Excellent between-session reliability (ICC ≥ 0.9; CV ≤ 5.3) was observed for the mobile app variables.

The 1STS induces significant levels of fatigability. The fatigability indicators derived from the mobile app demonstrated remarkable reliability. Utilizing this user-friendly interface for computing fatigability may empower professionals to acquire insightful complementary indicators from the 1STS.