One of the most popular New Year’s resolutions is to start an exercise program. The dropout rate for beginners is high. This is particularly true for weight training. There is no weight training program which will work for everyone; however, there are basic principles most programs have in common.
Let’s start with some muscle science. Humans have two types of muscle fiber, which are known as Type I and Type II fibers. Using an example of a chicken, the Type I fibers are the dark meat; these fibers are highly aerobic, and can contract for a long time. Type II fibers are the white meat; they produce more force than Type I fibers, but fatigue quickly. In general, human muscle is about 50/50 Type I/Type II fibers. Athletes may depart from this, however. Muscle adaptation to weight training is a two-phase process. The first change, which begins after the first training session, involves the nervous system. More muscle fibers can be activated, and the rate at which they activate speeds up. The second phase, which begins 4-8 weeks later, is an increase in muscle fiber size, otherwise known as hypertrophy. Muscle hypertrophy most commonly occurs through an increase in muscle fiber diameter, though hypertrophy can also be a result of increases in muscle fiber length.
Muscle contracts in three different ways; concentric (where the muscle shortens against resistance,) eccentric (where the muscle lengthens against resistance,) and isometric (where the muscle contracts, but does not shorten or lengthen.) During eccentric contractions, the muscle is lengthening while contracting; this can cause microscopic tears in the fibers, and these tears are the source of the day after soreness (commonly known at delayed onset muscle soreness, or DOMS.) DOMS is a normal part of muscular adaptation to weight training; this is also why it’s important not to lift too much too soon, as DOMS can be very painful!
What about sets/repetitions/frequency? For the first two weeks, beginners should perform 1-2 sets per major muscle group (chest, upper back, thighs, etc.) These sets should not be until fatigue (you can’t do anymore reps.) You should stop a few reps before the fatigue point. This will reduce the risk of developing DOMS (though a little soreness is normal.) After the two weeks, you can add more sets, and take the sets to fatigue. How many sets depends on individual goals. If you just want to get in better shape, 3 sets per muscle group is fine. If your goal is to gain serious muscle mass, higher numbers of sets (12-18 per muscle group per week) are necessary. The number of repetitions per set can be anywhere from 6-25, if the sets are to fatigue. It’s best to wait 48-72 hours between when you’ve worked a muscle group the first time before you work it again; shorter intervals don’t allow enough recovery time. Rest periods between sets should be 2-3 minutes, for the same reason. Total weekly volume is more important than frequency. For example, if your goal was to perform 12 sets/week of chest exercises, whether you performed one day with 12 sets, two days with 6 sets, or three days with 4 sets, the benefits would be the same.
I recommend sticking to weight training machines, rather than free weights (barbells, dumbbells, etc.) for the first few weeks of a program. Weight training is safe; however, 90% of weight training injuries occur with free weights. This is because with free weights, there is a skill component to performing the exercises correctly. Resistance training machines, by contrast, have a low skill component, and instruction on how to use weight machines is available on the equipment.
If you would like more information on starting a strength training program, contact me at 846-1186.