I am a strong advocate of resistance training to promote health and preserve the ability to take on everyday physical challenges and function well late in life. An effective routine is two resistance training workouts per week, and three or more cardio workouts.

You have the option of joining a commercial gym or working out at home and both offer advantages and disadvantages. At a gym, you have machines with easily adjusted weight stacks, plus the movements are fixed. You also have professionals who can teach you the movements and help you craft a workout.

Or, you may choose the convenience of working out at home on your own. I regularly receive questions from readers requesting advice on how to begin.  My response is to simplify resistance training, breaking it down to basics that anyone can apply. Let me add, before beginning any vigorous exercise program, especially resistance training, if you are 35 or older, see your doc for a complete checkup and clearance to participate.

 Start by understanding what the major muscles, or muscle groups, do when they contract. Here are some examples.

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In each movement, there are two phases. Concentric muscle contractions overcome the pull of gravity, whereas eccentric contractions resist gravity. For example, hold a weight in your right hand, bend the elbow and bring the weight up to your chin. This entails a concentric contraction. Next, in an eccentric contraction, you gradually lower the weight back to the starting point by resisting downward momentum (resisting the pull of gravity). Both phases are important and a very strict form in both phases is necessary to promote increased strength and avoid injury.

Resistance training movements are grouped into sets of repetitions. One set may be for 10 reps, followed by a brief rest period, and the second set of 10 reps, and so forth. The number of reps performed per set can vary widely, but the typical range is 10 to 25 reps per set. 

When crafting a workout, experiment to determine how much weight to use for each exercise that fits the number of reps per set you choose (10, 15, 20, etc). The weight should challenge the working muscle and cause fatigue. The key factor for each set is to continue repetitions to the point where you cannot do "one more rep." As the muscle fatigues, resist the temptation to cheat by bending or swinging the weight. All reps must be highly controlled, slow, and perfectly strict.

You need to rest after each set but keep the rest period to a maximum of 30 to 60 seconds, the shorter the better. One aspect of resistance training that is misunderstood is the need to perform the same number of reps on every set (for example, three sets of 10 reps). To do so often inspires a lengthy rest period to make sure you have fully recovered from one set to the next and can get the full number of reps.

A better approach is to rest only briefly and don’t worry about the number of reps on sets two or three. Instead, know that it’s a good set if you push the muscle to fatigue and cannot perform "one more" rep. Thus, you might do 10 reps on the first set, rest very briefly (30 seconds) and perform only seven reps on the second, then five on the third, with good results.

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In addition to being more productive, this approach also will shorten the length of your workout.

Start with a "plank" by assuming the pushup position and holding this position as long as you can, gradually increasing the time. This is a great warmup and it's how I start my resistance training workouts. If this is too demanding, modify the plank by resting the weight on your knees instead of the toes. When you cannot hold the plank position any longer, shift from the toes to the knees and begin doing modified pushups, each one going a little lower as you are able. This exercise has many benefits as pushups work the chest, shoulder, and triceps muscles, and planks are a great exercise for the core.

For the biceps, hold a dumbbell in each hand and alternately contract and bring the weight to your chin, then lower slowly. To strengthen the shoulders, raise the dumbbells in each hand to the front to at least eye level, then lower. You can do a full set to the front or you can alternate raising to the front, then to the side, then the front, etc.

To work the thighs, a dumbbell in each hand, go from a standing position to sitting, bending the knees to 90 degrees, then stand and repeat. For the calf muscles, hold onto the back of a chair for balance, then rise up on your toes, lower, and repeat as many as possible. As the calf muscles get stronger, rise up on one leg only, doing as many as you can.

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A final thought. Muscles are smart and they adjust quickly to demands. Therefore, don’t get in a rut with always using the same approach. Change things up with a variety of different sets and reps, and alter the order of your exercises. The only aspect that should remain constant is pushing the muscle to fatigue in each set.

Reach Bryant Stamford, a professor of kinesiology and integrative physiology at Hanover College, at stamford@hanover.edu.