if your goal is to be an aold schwarzenegger lookalike, th you're going to have to use heavier weights. strength training so builds muscular endurance, the ability to contract a muscle repeatedly. it's muscular endurance that keeps our arms and legs moving during aerobic exercise. aerobic exercise, in turn, builds cardiovascular endurance. mirich: it's been well documented that we need to perform an aerobic activity to get our heart rate to our appropriate target value for at least 30 minutes, and ideally on a daily basis, at a minimum of three to four days a week. and the simplest of that is pure walking. the reason for that is that it has a very low injury risk and a high benefit risk in both cardiovascular, bone, osteoporosis, weight reduction, lower risk of diabetes because you're not overweight and obese. other activities such as bicycling and swimming or aqua aerobics or water exercise programs, when performed appropriately, have the same low impact aerobic types of benefit. what we're looking at is aerobic exercise, so moving arms and legs, all four limbs together. and it's impo