Table 5.

A hierarchical regression showing predictors of WMSDs

	B	Std. error	β	p	R	R2	ΔR2
Step 1
(Constant)	32.656	1.986		0.000	0.073	0.005
Sex	−1.088	1.067	−0.057	0.309
Age	0.349	0.455	0.043	0.445
Step 2
(Constant)	18.719	3.891		0.000	0.237	0.056	0.051
Sex	−0.804	1.043	−0.042	0.441
Age	0.408	0.444	0.050	0.359
WD	0.458	0.111	0.226	0.000
Step 3
(Constant)	11.071	4.307		0.011	0.313	0.098	0.042
Sex	−0.412	1.026	−0.022	0.688
Age	0.120	0.442	0.015	0.787
WD	0.359	0.112	0.177	0.001
TCs	0.282	0.074	0.214	0.000
Step 4
(Constant)	14.083	4.349		0.001	0.355	0.126	0.028
Sex	−0.674	1.015	−0.035	0.507
Age	0.012	0.437	0.002	0.978
WD	0.271	0.114	0.134	0.017
TCs	0.294	0.073	0.224	0.000
WD × TC	−0.049	0.015	−0.174	0.002

B, unstandardized beta; Std. error, standard error; TCs, task characteristics; β, standardized beta; R², R square; ΔR², R² change; p, significance level; WD, work demand; WD × TC, work demand × task characteristics.