most dont.  so i would follow that advise. but i cant keep strength without some heavy resistance; so when i am training training muay thai, i go in gym 1x week. do whole body in compound ex only. like 1-2 sets. 3-5 reps. a rep or 2 short of failure.  so like
rack deadlift, bb rows, chest press, leg press.  done. but thats me and maybe inly a few other guys i meet.  most dont.  they do explosive stuff like burbees and cardio like running/ skipping.  most grapplers i know do nothing but train bjj. thats it.  
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