The 30-Second Chair-Stand Test (30CST) was evaluated for reliability and validity in 54 women with endometriosis across three time points: in-clinic baseline (T1), at-home pre-menstruation (T2), and at-home during menstruation (T3).
Reliability was high across all settings (ICC: 0.985, 0.975, 0.981 at T1–T3). During menstruation, women performed significantly fewer repetitions than pre-menstruation (mean difference = −1.22 reps, p < 0.001; SRM = −0.436). Women with high pain scores (≥7) performed significantly fewer reps than those with lower scores (p < 0.001; Cohen's d = 1.59).
Small sample (n = 54) limits generalizability. Self-administered home testing relies on participant adherence and self-report accuracy. No comparator group of women without endometriosis was included.
The 30CST is a simple, reliable tool that clinicians can use to track functional capacity in women with endometriosis — including at home, across the menstrual cycle. Women reporting pain ≥7 show meaningfully worse physical performance, making the 30CST a practical complement to pain assessment in this population.
