Most guys pay lip service to including aerobics and strength exercise in their training programs, but the majority gravitate to one form or the other. Hardcore runners, for example, will push some weights from time to time and guys with big bench presses will take a few laps, but that’s usually the exception rather than the rule. New research shows that if you like to lift weights, you don’t have to have the body of a marathon runner to get the benefits of aerobics. In fact, doing the right kind of cardio will help you gain muscle mass.
Advances in genetics and biochemistry have shown us that it’s possible to build muscle and aerobic capacity at the same time. Even better, you can get a complete strength and cardiovascular workout in about 40 minutes. This is no “get fit without cost” training program. It is difficult and it hurts, but you can build muscle while maximizing cardiovascular capacity.
Grow with Cardio
Until recently, exercise recommendations from professional organizations such as the American College of Sports Medicine (ACSM) and the American Heart Association emphasized aerobics and only included strength training as an afterthought. In the past 10 years, scientists discovered that strength training had a huge effect on metabolic health and provided many of the same benefits as aerobics.
Some of the benefits of weight training include increased resting metabolic rate, improved blood sugar control and blood fat profiles, decreased gastrointestinal transit time (reducing the risk of colon cancer), reduced resting blood pressure, increased bone density and muscle mass, fewer symptoms from arthritis, reduced risk of low back pain, improved flexibility, and increased aerobic capacity. Since these are many of the same benefits of aerobics, combining aerobic and resistive exercise methods might provide the best of both worlds— improved metabolic health and increased muscle mass.
Conventional wisdom among many athletes and coaches is that you must lift heavy weights to get big and strong. Sophisticated biochemical studies on muscle protein synthesis show that this isn’t true. Training at intensities close to momentary muscle failure causes greater increases in muscle size than practicing high-weight, low-rep training programs. These studies showed that gains were sometimes twice as great from using momentary muscle failure training methods as training with heavy weights for fewer reps.
When exercising to increase muscle growth, your goal should be to activate all the motor units within a muscle group, which maximizes the stimulus that forces muscle fibers to increase in size. A motor unit consists of a nerve from the spine connected to muscle fibers. The principle fiber types in humans are Type I, IIa, and IIx. Type I fibers are used first, followed by the IIa and IIx fibers in response to fatigue or heavier loads.
New genetic and biochemical studies on muscle growth showed that muscle protein synthesis is best using a combination of muscle overload and aerobics. The nucleus is the center for protein synthesis in cells throughout the body. Skeletal muscle cells are unique because they contain more than one nucleus. Muscle cells increase cell nuclei by generating satellite cells in response to cell damage and muscle tension caused by weight training. This increases the capacity for muscle hypertrophy in the future and helps trained muscles maintain increased size.
The body tries to maintain a balance that scientist call homeostasis. For example, try to lose weight rapidly and metabolic control mechanisms increase appetite and slow metabolic rate. Muscle size also has a balance control. A chemical called myostatin prevents muscles from getting too large. It is balanced by follistatin, which promotes muscle growth.
Danish scientists showed that the liver increases follistatin output and decreases myostatin during and shortly after aerobic exercise. They also found that intense training with light loads increased satellite cells as well as heavier loads. Intense aerobics and muscular overload exercise also increase blood levels of growth hormone and IGF-1, both of which are critical for promoting muscle growth. The workout in this article combines high-intensity interval training and kettlebell training, which boost fitness and increase muscle mass.