napénjati to strain; to stretch; (lok) to bend; medicina to cause flatulence
napénjati oči to strain one's eyes
napénjati vse svoje sile to make every effort, to exert oneself to the utmost
to napenja medicina that causes flatulence
napénjati se (figurativno) to struggle, to endeavour, to exert oneself to the utmost, (pri delu) to overwork