maintain, exercise, wield, enforce, work, bring into play, energize, purchase, play, press, more...

relax, rest, idle, neglect, ignore

small, former, latter, general, over, great, few, current, liquid, particular, present

put effort into,   put in effort,   use muscle power,   wield influence,   to apply a force,   expend energy,   apply effort,   apply force,   to spend energy,   push himself