They are not old-guy jeans! Check out the construction of the high-drag/low-speed clothing designed for highly trained operators who are members of Special Olympics Forces-type units. The same diamond crotch gusset is in their tacti-cool pants.
Be sure that you get a set of SideWinder suspenders to go with your jeans. Not only do they work better than typical fore-and-aft suspenders*, they make the sheeple think you are wearing a shoulder rig.
* - I abhor with all my soul the 3-point Y style of suspenders - wearing them is like getting a repeated wedgie. Thank goodness that duty gear manufacturers and the .mil are going to H-harness styles.