Table 3

Hierarchical Linear Models Analyses Predicting Exercise Change and Maintenance following the Intervention

Statistical significance of coefficient γ₃₁ is indicative of maintenance effects using the following model:

Level 1 model: Outcome = β_0j + β_1jX₁ + β_2jX₂ + β_2jX₂+ r_ij

Level 2 model: T₁ β_0j= γ₀₀ + γ₀₁ Gr_j + u_oj

T₂ β_1j= γ₁₀ + γ₁₁ Gr_j

T₃ β_2j= γ₂₀ + γ₂₁ Gr_j

T₄ β_2j= γ₃₀ + γ₃₁ Gr_j

where i: 1 ....N individuals ; r_ij: level 1 error term ; γ_ij : coefficients for parameters ; u_oj: level-2 random effect ; β: coefficient ; Gr: group membership (1 = experimental, 0 = control) ; X₁: dummy variable (1 = pre-intervention, 0 = otherwise) ; X₂: dummy variable(1 = post-intervention-1, 0 = otherwise); X₃: dummy variable(1 = post-intervention-2, 0 = otherwise)

Meaning of Coefficients:

γ₀₀ = Predicted value in outcome variable at baseline for participants in control group

γ₀₁ Gr_j = Predicted difference in outcome variable at baseline for participants in experimental group

γ₁₀ = Predicted change in outcome variable from baseline to pre-intervention for participants in control group

γ₁₁ Gr_j = Predicted difference in change in outcome variable from baseline to pre-intervention for participants in experimental group

γ₂₀ = Predicted change in outcome variable from baseline to post-intervention1 for participants in control group

γ₂₁ Gr_j = Predicted difference in change in outcome variable from baseline to post-intervention-1 for participants in experimental group

γ₃₀ = Predicted change in outcome variable from baseline to post-intervention-2 for participants in control

γ₃₁ Gr_j = Predicted difference in change in outcome variable from baseline to post-intervention-2 for participants in experimental group.

^a significance of the changes that had occurred between post-intervention-1 and post-intervention-2

Nour et al. International Journal of Behavioral Nutrition and Physical Activity 2007 4:22   doi:10.1186/1479-5868-4-22