Competitive gaming and playing on a lower-specced machine

Stupid question:

Is there any truth to the belief that if you train your <insert competitive game here e.g. Dota 2> skills on a sub-par pc, when you play on a maxed-out one you play better (much like jogging around with ankle weights then taking them off to improve your vertical leap)?

Conversely, since I have to adjust to lower frame rates and less responsive interfaces on a lower-specced machine, does playing there hurt my overall skill growth?