Ever notice how strength training and aerobic exercise go together? Aerobic exercise accentuates strength training because you have more endurance. Strength training makes aerobic exercise better, more fun, because you have more power. Like marshmallows and campfires or vanilla ice cream and hot apple pie, each one enhances the experience of the other.
Awareness of these possibilities helps you get more out of the valuable time you spend exercising.
Strength training by itself doesn't provide much of an aerobic benefit. Strength training by its very nature is an anaerobic activity. Some aerobic benefit can be gained by doing five- or six-exercise supersets. But that's not the main point of lifting weights.
Aerobic exercise by itself doesn't provide much of a strength benefit. Aerobic exercise by its very nature is a glucose-burning endurance activity. The main muscle that gets stronger is your heart, and that's why you're doing aerobic activities. You don't really increase lean muscle mass by doing aerobic exercise.
But when you do both activities on a regular, weekly basis, magical things happen. You notice you're getting stronger on your strength training days and getting faster and have more endurance on your aerobic training days because you're doing both consistently.
From the viewpoint of exercise physiology, focusing on things like VO2 max and oxygen-consumption rates, the combination of strength training and aerobic exercise generates a positive feedback loop of training effects. Done correctly, strength training not only strengthens the prime movers involved in the specific exercise, but also the accessory and stabilizing muscles. These latter muscles come into play during aerobics, too, and provide a strong base to support the prime movers of aerobic activity - the quadriceps, hamstrings, and calf muscles.
Aerobic exercise itself trains accessory and stabilizing muscles only minimally. So strength training is needed to complete the biomechanical picture and allow you to get the most out of your aerobic training.
Similarly, aerobic exercise strengthens your cardiovascular and pulmonary systems. Your cardiac stroke volume increases, meaning your heart is pumping more blood each time it contracts. Your lung capacity increases so you take in more air (and, therefore, more oxygen) with each breath. More air and more blood means more nutrients reaching hard-working muscles during your strength training sessions.
In effect, aerobic exercise and strength training complete each other. When you engage in both activities, consistently, week by week, you are maximizing your training benefits across the board.1,2,3 Together, these life-affirming activities help you paint a beautiful picture of vibrant health and well-being.
1Field T: Exercise research on children and adolescents. Complement Ther Clin Pract 18(1):54-59, 2012
2Walsh NP, et al: Position statement. Part one: Immune function and exercise. Exerc Immunol Rev 17:6-63, 2011
3Sung J, et al: Prevalence of Coronary Atherosclerosis in Asymptomatic Middle-Age Men With High Aerobic Fitness. Am J Cardiol Dec 21 2011 (Epub ahead of print)