Table 3.

Mean values of MRI assessed disc diameter (mm) at the start of the work day and 4 hours later for day 1 and for day 2

Measurement	Day 1 Start	Day 1 End	p-value*	Day 2 Start	Day 2 End	p-value*
	Mean(SD)	Mean(SD)		Mean(SD)	Mean(SD)
L1-2	35.13(1.54)	34.81(1.89)	0.256	34.67(1.24)	34.83(2.03)	0.715
L2-3	36.96(1.52)	36.93(1.87)	0.870	36.83(1.72)	36.88(1.68)	0.386
L3-4	37.58(1.16)	37.38(1.48)	0.548	37.45(1.29)	37.33(0.95)	0.669
L4-5	38.11(1.63)	37.95(2.14)	0.665	37.13(1.62)	37.48(1.96)	0.059
L5-S1	36.50(2.16)	36.99(1.91)	0.080	36.14(1.86)	36.61(2.08)	0.130

^*Paired t-test comparing mean values from start to end (Wilcoxon Signed Rank test comparing median values if normality not satisfied)