A comparative study of the five-repetition sit-to-stand test and the 30-second sit-to-stand test to assess exercise tolerance in COPD patients

Figures & data

Table 1 Patient characteristics (median [IQR] or number [%])

	Total sample (N=128)	Range
Age, years	65 (11)	34–81
Sex, male:female	86:42	N/A
FEV1, L	1.23 (1)	0.43–2.89
FEV1 % pred	54 (36.65)	15.0–100.0
FVC, L	2.5 (1.23)	0.97–4.78
FEV1/FVC, %	51 (17.97)	25.0–69.0
RV, L	3.6 (2.18)	1.34–9.21
TLC, L	6.59 (2.15)	3.68–10.32
RV/TLC, %	59.62 (19)	31.00–91.39
BMI, kg/m^2	23.7 (5.45)	15.5–33.7
FFMI, kg/m^2	16.68 (3.21)	10.43–22.05
Height, cm	163.25 (11.63)	142.0–180.0
Weight, kg	62 (16.7)	32.5–95.0
mMRC	2 (2)	0–4
≥2, n (%)	72 (56.25)	N/A
CAT	20 (9.25)	0–40
5STS score, seconds	6.57 (1.28)	3.30–15.60
30STS score, repetitions	24 (5.5)	6–43
6MWD, m	361 (109.5)	108–554
QMSa, kg	7.63 (2.22)	16.33–68.95

Note:

a No significant difference was observed between the maximal isometric force generated on each side of the lower limb (P=0.714).

Abbreviations: N/A, not applicable; FEV₁% pred, FEV percentage predicted; RV, residual volume; TLC, total lung capacity; BMI, body mass index; FFMI, fat-free mass index; CAT, COPD Assessment Test; 5STS, five-repetition sit-to-stand test; 30STS, 30-second sit-to-stand test; 6MWD, 6-minute walk distance; QMS, quadriceps muscle strength.

Table 2 Correlations of STSTs with participant characteristics

	5STS score	P-value	30STS score	P-value
6MWD	−0.508	<0.001	0.528	<0.001
QMS	−0.401	<0.001	0.398	<0.001
FEV1 % pred	−0.154	0.083	0.309	<0.001
RV/TLC	0.344	0.001	−0.498	<0.001
mMRC	0.289	0.001	−0.408	<0.001
CAT	0.160	0.073	−0.252	0.005
Age	0.301	0.001	−0.297	0.001

Abbreviations: STST, sit-to-stand test; 5STS, five-repetition sit-to-stand test; 30STS, 30-second sit-to-stand test; 6MWD, 6-minute walk distance; QMS, quadriceps muscle strength; FEV₁% pred, FEV₁ percentage predicted; RV, residual volume; TLC, total lung capacity; CAT, COPD Assessment Test.

Figure 1 Relationships between the two modes of STSTs and the 6MWD and QMS.

Notes: (A) Relationship between the 5STS score and the 6MWD, N=128. (B) Relationship between the 5STS score and QMS, N=128. (C) Relationship between the 30STS score and the 6MWD, n=126. (D) Relationship between 30STS and QMS, n=126.
Abbreviations: STST, sit-to-stand test; QMS, quadriceps muscle strength; 5STS, five-repetition sit-to-stand test; 30STS, 30-second sit-to-stand test; 6MWD, 6-minute walk distance.

Figure 2 ROC curve analysis of the 5STS score (A) and the 30STS score (B) for predicting 6MWD <350 m.

Abbreviations: ROC, receiver operating characteristic; 5STS, five-repetition sit-to-stand test; 30STS, 30-second sit-to-stand test; AUC, area under the curve.