This is a paid asset, but now you can download Body Builder for FREE, but please remember this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Detail this asset from Unity Store: Original Link
Body Builder v1.0
Realistic Body Builder Model.
3 LODs:
LOD0: 4000 tris
LOD1: 2300 tris
LOD2: 1800 tris.
Two PBR Standard Metallic materials.
Albedo, Normal and Metallic/Smoothness maps in 2k resolution.
Body texture in psd format included so you can change the text on the shirt,
Model has NO animations. It is however skinned and Mecanim ready. You can use Mocap or any other Mecanim compatible animation to live him up. It has animatable eyes too.
Video bellow uses Mocap Animations to show you the skinning and the range of motions available to the model.