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Table 4 Regression analyses of the effects of the GA + , GA, and GI interventions compared to the guideline only (group G) on behavioural and psychological outcomes

From: Promoting an active choice among physically inactive adults: a randomised web-based four-arm experiment

Outcome

Group

Pre-intervention measurement (T0)

Follow-up measurement (T2) versus T0

  

Median (IQR)a

 

Median (IQR)a

β [95% CI]

Physical activity,

total MET-minutes per week

(n = 311)

GA + 

640.00 (887.25)

 

855.00 (1305.50)

β = 1.09 [0.79; 1.51]b

GA

594.00 (713.75)

 

720.00 (1029.00)

β = 0.98 [0.73; 1.31]b

GI

758.00 (1188.00)

 

897.00 (1134.00)

β = 1.16 [0.88; 1.54]b

G

672.00 (993.00)

 

844.00 (1158.00)

 
  

Mean (SD) or N (%)

β or OR [95% CI]

Mean (SD) or N (%)

β or OR [95% CI]

Physical activity,

category ‘moderate/high’c

(n = 477)

GA + 

46 (51.7%)

 

34 (35.4%)

OR = 0.62 [0.35; 1.11]

GA

46 (36.5%)

 

53 (40.8%)

OR = 0.93 [0.55; 1.57]

GI

58 (40.8%)

 

56 (36.8%)

OR = 0.87 [0.53; 1.45]

G

63 (43.4%)

 

65 (43.6%)

 

Sitting time,

minutes per day

(n = 408)

GA + 

522.34 (217.77)

 

519.35 (218.66)

β = 17.84 [-25.66; 61.33]

GA

525.49 (199.00)

 

504.25 (224.45)

β = 2.42 [-37.22; 42.05]

GI

507.02 (190.33)

 

477.57 (193.45)

β = -11.07 [-48.93; 26.78]

G

497.45 (199.77)

 

482.22 (200.55)

 

Perceived increase in physical activity

(n = 499)

GA + 

  

37 (44.0%)

OR = 2.61** [1.44; 4.72]

GA

  

36 (28.3%)

OR = 1.19 [0.67; 2.10]

GI

  

38 (26.6%)

OR = 1.06 [0.60; 1.87]

G

  

36 (24.8%)

 
  

Post-intervention measurement (T1)

Follow-up measurement (T2) versus T1

Intention

(n = 564)

GA + 

87 (87.0%)

OR = 1.65 [0.82; 3.32]

  

GA

108 (78.3%)

OR = 0.89 [0.51; 1.55]

  

GI

135 (82.3%)

OR = 1.15 [0.66; 2.00]

  

G

130 (80.2%)

   

Intention strength

(T1: n = 564; T2: n = 491)

GA + 

6.32 (2.40)

β = 0.41 [-0.14; 0.97]

6.23 (2.31)

β = 0.08 [-0.39; 0.56]

GA

6.17 (2.23)

β = 0.27 [-0.24; 0.77]

6.18 (2.30)

β = 0.12 [-0.31; 0.55]

GI

6.54 (2.07)

β = 0.64* [0.15; 1.12]

6.45 (2.21)

β = 0.16 [-0.25; 0.58]

G

5.91 (2.26)

 

5.90 (2.08)

 

Active choice

(n = 564)

GA + 

3.66 (0.50)

β = 0.09 [-0.03; 0.22]

  

GA

3.73 (0.49)

β = 0.16** [0.04; 0.27]

  

GI

3.70 (0.51)

β = 0.13* [0.02; 0.24]

  

G

3.57 (0.49)

   

Autonomy: ‘Own choice’,

(n = 564)

GA + 

6.83 (2.16)

β = 0.22 [-0.30; 0.74]

  

GA

6.80 (1.91)

β = 0.19 [-0.28; 0.66]

  

GI

7.11 (2.04)

β = 0.50* [0.05; 0.95]

  

G

6.61 (2.16)

   

Autonomy: ‘Imposed choice’

(n = 564)

GA + 

4.48 (2.57)

β = 0.26 [-0.34; 0.87]

  

GA

4.61 (2.51)

β = 0.39 [-0.16; 0.95]

  

GI

4.34 (2.41)

β = 0.12 [-0.41; 0.65]

  

G

4.22 (2.31)

   

Commitment

(T1: n = 460; T2: n = 401)

GA + 

7.26 (1.54)

β = 0.44* [0.04; 0.84]

6.33 (2.11)

β = 0.19 [-0.39; 0.77]

GA

7.09 (1.25)

β = 0.26 [-0.11; 0.63]

6.17 (2.20)

β = 0.14 [-0.39; 0.67]

GI

7.22 (1.48)

β = 0.39* [0.04; 0.74]

6.43 (2.22)

β = 0.32 [-0.18; 0.83]

G

6.82 (1.52)

 

5.87 (2.03)

 

Self-efficacy (composite score)

(n = 460)

GA + 

5.74 (1.62)

β = 0.26 [-0.22; 0.74]

  

GA

5.81 (1.75)

β = 0.32 [-0.11; 0.76]

  

GI

5.85 (1.78)

β = 0.37 [-0.05; 0.79]

  

G

5.48 (1.72)

   

Self-efficacy

(single item) (n = 401)

GA + 

6.07 (1.75)

 

5.51 (2.23)

β = 0.16 [-0.37; 0.70]

GA

6.15 (1.82)

 

5.56 (2.07)

β = 0.17 [-0.31; 0.66]

GI

6.21 (1.87)

 

5.81 (2.01)

β = 0.38 [-0.09; 0.84]

G

5.94 (1.85)

 

5.28 (1.95)

 

Satisfaction

(n = 564)

GA + 

6.57 (1.90)

β = 0.32 [-0.16; 0.80]

  

GA

6.37 (1.99)

β = 0.12 [-0.32; 0.55]

  

GI

6.53 (1.88)

β = 0.28 [-0.14; 0.70]

  

G

6.25 (1.92)

   

Alignment of choice with personal values

(n = 564)

GA + 

7.16 (1.79)

β = 0.28 [-0.17; 0.74]

  

GA

7.08 (1.82)

β = 0.20 [-0.21; 0.62]

  

GI

7.27 (1.93)

β = 0.39 [-0.00; 0.79]

  

G

6.88 (1.69)

   
  1. IQR interquartile range, CI confidence interval, MET metabolic equivalent of task, SD standard deviation, β regression coefficient, OR odds ratio
  2. *P < .05
  3. **P < .01
  4. aThe median and (IQR) are reported as the distribution is skewed to the right
  5. bThe results were log transformed for the analysis (using the natural logarithm) and subsequently back transformed
  6. cThe ‘moderate/high’ category was compared to the ‘low’ category