Skip to main content

Table 2 Mean scores for outcome measures by group, with (un)standardized mean differences

From: The effect of a one-year vigorous physical activity intervention on fitness, cognitive performance and mental health in young adolescents: the Fit to Study cluster randomised controlled trial

  Intervention group (46 schools, n = 7860) Control group (47 schools, n = 8157) Adjusted mean difference1 (95% CI)
Baseline Post Baseline Post Unstandardized Standardized2
M (SD) M (SD) M (SD) M (SD)
20MSR
 Fitness, laps 36.11 (20.75) 41.36 (21.95) 37.85 (20.65) 42.37 (22.28) 0.48 (−2.52, 3.48) 0.02 (−0.11, 0.16)
Reaction time task
 RT3, ms 378.7 (86.65) 378.58 (99.46) 380.21 (89.7) 376.07 (95.94) 3.63 (−7.04, 14.3) 0.04 (−0.07, 0.15)
Relational memory task
 Accuracy, % 59.75 (11.93) 59.53 (13.05) 59.76 (12.24) 60.78 (13.08) −1.37 (−3, 0.26) −0.1 (−0.23, 0.02)
Two-back task
 Accuracy, % 54.43 (18.46) 55.24 (20.9) 53.4 (18.74) 55.48 (20.99) −0.96 (−3.38, 1.47) −0.05 (−0.16, 0.07)
 RT3, ms 857.67 (164.84) 802.26 (175.03) 844.17 (171.04) 799.45 (174.9) −4.25 (−23.09, 14.58) −0.02 (−0.13, 0.08)
Flanker task
 Accuracy congruent, % 82.83 (17.14) 84.21 (16.57) 81.91 (16.81) 84.55 (16.44) −0.92 (−2.38, 0.53) −0.06 (−0.14, 0.03)
 Accuracy incongruent, % 60.22 (20.67) 62.2 (20.33) 60.02 (19.55) 63.06 (19.65) −1.05 (−2.86, 0.76) −0.05 (−0.14, 0.04)
 RT3 congruent, ms 490.26 (92.13) 476.82 (84.22) 490.35 (94.51) 479.19 (81.26) −2.49 (−10.37, 5.39) −0.03 (−0.13, 0.07)
 RT3 incongruent, ms 552.9 (127.12) 537.89 (108.67) 548.15 (126.16) 541.25 (109.06) −5.74 (−15.41, 3.93) −0.05 (−0.14, 0.04)
Colour-shape switching task
 Accuracy non-switch, % 73.27 (17.21) 75.18 (17.61) 72.88 (17.25) 75.61 (17.48) −0.76 (−2.64, 1.12) −0.04 (−0.15, 0.06)
 Accuracy switch, % 69.51 (16.89) 71.47 (17.65) 69.36 (17.15) 71.56 (17.59) −0.32 (−2.16, 1.52) −0.02 (−0.12, 0.09)
 RT3 non-switch, ms 1075.67 (352.18) 974.95 (320.46) 1051.07 (337.52) 970.87 (318.08) −5.86 (−34.33, 22.61) −0.02 (−0.11, 0.07)
 RT3 switch, ms 1452.99 (602.23) 1331.63 (562.05) 1404.21 (569.5) 1321.97 (544.16) −13.18 (−66.27, 39.91) −0.02 (−0.12, 0.07)
Psychosocial problems
 Internalising score3 5.1 (3.56) 5.47 (3.72) 5.07 (3.49) 5.25 (3.6) 0.19 (−0.18, 0.57) 0.05 (−0.05, 0.16)
 Externalising score3 6.34 (3.85) 6.73 (3.78) 6.29 (3.74) 6.45 (3.8) 0.24 (−0.13, 0.61) 0.06 (−0.03, 0.16)
Self-esteem
 Global 4.39 (0.94) 4.23 (1.03) 4.43 (0.9) 4.3 (0.97) −0.05 (−0.22, 0.12) −0.05 (−0.22, 0.12)
 Physical 4.36 (1.31) 4.07 (1.41) 4.44 (1.27) 4.14 (1.36) −0.02 (−0.22, 0.19) −0.01 (−0.16, 0.14)
  1. Abbreviations: CRF cardiorespiratory fitness, ms millisecond, RT reaction time
  2. 1 Adjusted mean difference, adjusted for clustering, baseline values of the outcome variable and school gender-type
  3. 2 The outcome was standardized (mean = 0, SD = 1), prior to fitting the baseline and stratification-variable adjusted model
  4. Lower scores represent better performance