Triceps brachii muscle thickness (F(1,20) = 8.071, p = 0.010, η2 = 0.288), reflecting a large effect of time, whereas the group effect was not significant ( p = 0.952), and the time × group interaction approached significance ( p = 0.058).
The significant main effect of time and the borderline significant time × group interaction observed in the thickness of the M. triceps brachii suggest that this muscle demonstrates time-dependent development, with potentially more pronounced but not statistically robust improvements in the intervention group.