Low dynamic muscle strength and its associations with fatigue, functional performance, and quality of life in premenopausal patients with systemic lupus erythematosus and low disease activity: a case–control study

Table 4 Dynamic muscle strength (1-RM) in SLE patients and controls*

Variable (1-RM)	SLE	CONTROLS	Difference between means	P-value
Variable (1-RM)	(n = 25)	(n = 25)	(95% CI)^#	P-value
Leg press, kg	71.1 ± 18.6	95.6 ± 19.7	24.5 (13.6; 35.5)	< 0.0001
Leg extension, kg	64.7 ± 10.6	72.9 ± 13.9	8.1 (1.1; 15.2)	0.0242
Leg curl, kg	30.2 ± 5.2	35.8 ± 6.9	5.6 (2.1; 9.1)	0.0022
Chest press, kg	34.7 ± 7.2	43.1 ± 7.9	8.4 (4.1; 12.7)	0.0002
Lat pulldown, kg	36.2 ± 6.4	41.8 ± 5.8	5.6 (2.2; 9.1)	0.0019
1-RM-total, kg	47.4 ± 8.1	57.8 ± 8.7	10.4 (5.7; 15.0)	< 0.0001
1-RM-total, kg/kg of body weight	0.8 ± 0.1	1.0 ± 0.1	0.2 (0.1; 0.2)	< 0.0001

* These values are expressed as the mean SD unless otherwise stated. † These variables are not normally distributed and therefore, are expressed as median. # Calculated only when Student’s t-test was used. SLE = systemic lupus erythematosus; CI = confidence interval of 95%; 1-RM = 1-RM consists of performing a full range of motion with the greatest possible load; 1-RM -total = sum of total load lifted in the 1-RM tests (i.e., leg press, leg extension, leg curl, chest press, and lat pulldown); 1-RM-total, kg/kg of body weight = median of the sum of the load of the 1-RM tests in leg press, leg extension, leg curl, chest press, and lat pulldown divided by body weight.

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