Although running was the predominant aerobic
activity among bodybuilders 20-30 years ago, most of today's athletes
prefer lower impact activities such as cycling, stair climbing, uphill
treadmill walking and swimming. Many bodybuilders today believe that
running can retard - or even reverse - strength and mass gains, even
though this hasn't been documented. Consider these factors :
Won't too much aerobic work
like running interfere with muscle building, perhaps even catabolism the
muscle mass we already have ?
Work of any kind consumes calories, energy that
could otherwise be devoted to recuperation and adaptation to other
training. Too much of any work - anaerobic / resistive or aerobic - can
interfere with muscle and strength building. Rather than run for 20
minutes three times a week, set a training goal such as increased muscle
mass or strength, less body-fat, general fitness for athletics or
health, You decide how much and what kinds of training will best help
you achieve your goals.