Stack lamella deformation depends on their orientation with respect to the loading axis, the intrinsic properties of the lamellae, and the mechanical coupling between crystalline and amorphous phases. The aim of this work is to investigate the influence of the stress transmitter (ST) density and the crystallinity X-c on the local deformation. A wide experimental campaign has been undertaken on several polyethylenes with controlled molecular parameters and subjected to different thermal treatments. The ST density has been evaluated by the natural draw ratio and calculated by the Brown's model. The local deformation was measured by SAXS along a tensile test by using the long period stretching of the equatorial lamella stacks. The ratio epsilon(local)/epsilon(macro) was found to be a constant close to 0.5. This surprising low value has highlighted that the equatorial regions could be either the stiffest zone of the spherulite or submitted to a lower stress. It is proposed that the stability of the ratio epsilon(local)/epsilon(macro) is the result of two opposite phenomena: On one hand, the increase of X-c leads to unload the equatorial regions due to partial percolation of the crystalline phase and so decreases the stresses. On the other hand, when increasing X-c, the ST density decreases which causes the decrease in the local equatorial modulus. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1535-1542, 2010