Is 10x400z with 90 sec rest maintaining 65-67 a good work out for a 4:20 miler like myself ? .. I want to hit 4:15 before the end of indoor season.
Is 10x400z with 90 sec rest maintaining 65-67 a good work out for a 4:20 miler like myself ? .. I want to hit 4:15 before the end of indoor season.