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Table 1 Participant characteristics

From: Physical inactivity is associated with narrower lumbar intervertebral discs, high fat content of paraspinal muscles and low back pain and disability

  Inactive Moderately active Active P
(0 days) (1 to 8 days) (9 to 14 days)
N = 15 N = 38 N = 19
Age (years) * 47.2 (1.3) 45.1 (0.7) 46.5 (1.5) 0.29
Gender (n, % female) ** 13 (86.7) 26 (68.4) 10 (52.6) 0.11
Weight (kg) * 99.0 (3.6) 96.5 (2.1) 84.4 (4.3) 0.02
Height (m) * 1.67 (0.01) 1.67 (0.01) 1.70 (0.02) 0.21
BMI (kgm −2 ) * 35.7 (1.3) 34.8 (0.8) 29.3 (1.5) 0.002
Intervertebral disc height (L1 to S1) (mm) *     
Average 10.2 (4.1) 10.6 (2.6) 11.8 (3.6) 0.01
Paraspinal muscle properties
CSA (cm 2 ) *     
Multifidus 6.9 (0.4) 6.9 (0.3) 7.2 (0.4) 0.76
Erector spinae 19.7 (1.1) 20.5 (0.7) 21.7 (1.0) 0.41
High fat content, n (%) **     
Multifidus 9 (60.0) 13 (34.2) 3 (15.8) 0.03
Erector spinae 5 (33.3) 7 (18.4) 1 (5.3) 0.11
Chronic low back pain grade, n (%) ***
Pain free 3 (20.0) 6 (15.8) 5 (26.3) 0.049
Low disability, low intensity 5 (33.3) 24 (63.2) 14 (73.7)
Low disability, high intensity 4 (26.7) 1 (2.6) 0 (0.0)
High disability, moderately limiting 1 (6.7) 4 (10.5) 0 (0.0)
High disability, severely limiting 2 (13.3) 3 (7.9) 0 (0.0)
High pain/disability, n (%) *** 7 (46.7) 8 (21.1) 0 (0.0) 0.004
  1. Results displayed as mean (standard error of the mean) unless otherwise stated. * P values determined from pairwise comparison among the estimated marginal means; ** P values determined from chi-squared test; *** P values determined from Fisher’s exact test. BMI, body mass index; CSA, cross-sectional area.