utthāpanair unnayanaiś
cālanaiḥ sthāpanair api
parasparaḿ jigīṣantāv
apacakratur ātmanaḥ
utthapanaih -- with lifting up; unnayanaih -- carrying; calanaih -- pushing away; sthapanaih -- holding stationary; api -- also; parasparam -- each other; jigishantau -- wanting victory; apacakratuh -- they harmed; atmanah -- (even) themselves.
Srila Jiva Gosvami explains that although Krishna and Balarama did not, of course, harm Themselves, it appeared that way to Canura, Mushtika and others of mundane vision. In other words, the Lords were fully absorbed in the pastime of being wrestlers.