The exercises are chosen to improve the fundamental movements of strength, develop a foundation for sports, aid in activities of daily life(ADL), and counteract typical movement and posture problems. Exercises that work the left and right sides of the body separately(unilateral) are preferred in order to include more muscles and coordination demands, and for some exercises to prevent forcing the joints into possibly injurious positions. In an actual program with more than 5 exercises though I will often use both the unilateral and bilateral versions to gain the advantages of both.
Strength can most basically be exerted as pushing, pulling, lifting, and rotating. All of these can involve either movement or resisting movement, and any movement can be with the body fixed and an external object moving(eg. standing still while lifting a weight) or with the body moving relative to a fixed object(eg. pull-ups on a bar.) A generalization is that a weight is held in the hands, moved, the core transmits the force to the lower body without twisting or bending, and the legs support and possibly also move the body. (This is a huge simplification.)
From Integrate Performance Fitness in Mountain View, here is my example five exercise workout, with very brief descriptions of how each should be done.
A bilateral stance is used here to enable lifting more weight and develop more strength in the larger muscles.
Exercise Tips: Keep the knees wide, and your weight on the heels.
Single Leg Deadlift
The deadlift works many similar lower body muscles as the squat, but puts the emphasis more into the glutes and the back of the legs. It continues the load up the back in what's known as the posterior chain, a major area of weakness for most people. The back of the shoulder is included, and again holding the weight in the hand means the arms are part of the lift. Standing on one leg while moving a heavy weight is excellent for developing the muscles in the lower leg and hips needed for stability. Because the hand opposite the working leg holds the weight, there's a large rotational force(transverse plane) to work against in lower range of the lift, and a lateral bending(frontal plane) to resist at the top of the lift. Correct form is essential for the Single Leg Deadlift.
Exercise Tips: Don't let the spine round at all. Push the hips backwards. Keep the weight close to the body, and have something beneath to tap the weight against.
With these first two exercises, lifting is well covered, resisting pushing and pulling are included, and good anti-rotation accomplished. But the hands do need to move things, and the next three exercises cover that.
Picking up things and holding them overhead is an important ADL, and strengthening the shoulders is helpful any time holding something is heavy is needed. The overhead press can help maintain shoulder mobility that is often lost with aging, however this also means that adequate shoulder and upper spine mobility is required to press at all. Injuries in the front of the shoulder are common, and the press can help prevent them if done correctly. Pressing with one hand at a time means more muscles are engaged to keep the weight in proper alignment, and since the hand can be rotated a healthy angle relative to the shoulder is possible. Doing the lift while standing will develop stability in the body down to the floor.
Exercise Tips: The weight should travel straight up and end above the shoulder blade. At the top the palm should rotate partially or completely facing inward. Don't lean back or arch the spine. NB: It may be necessary to improve shoulder and upper spine mobility to correctly perform this exercise.
Pulling the shoulders back(scapular retraction) and straightening the upper spine(thoracic extension) are a major shortcomings for most people, so an exercise that improves these is important to include. In the deadlift the upper back muscles work to hold a static position, here they actively create movement. I like doing rows in a lunge so that the body is somewhat supported but not entirely. Make certain the upper spine is held straight and not rounding forward.
Exercise Tips: Let the shoulder drop forward but not hang, then pull the shoulder up toward the ceiling and in toward the spine, without hunching toward the ear. Keep the elbow close to the torso. On each rep try to straighten the upper spine even more.
The push-up is last on the list because it is the least important. Still, it is a great exercise. While it fulfills the need to include pushing in the program(along with the overhead press), the best part of the push-up is the strong core it promotes when done correctly. The first priority is to hold the body straight with a neutral spine, as in a plank, then bend and straighten the arms to lower and raise a straight body. Pushups progress mainly by changing the angle of the body. They can be done at first with the hands elevated(a barbell rack works great for this), to hands and feet on the floor, to feet elevated. There are many variations, including doing each rep with one leg off the ground or picking up one hand for a moment at the top of each repetition. These will both add a anti-rotation element to the exercise.
Exercise Tips: Start with your body in a straight plank, but with one knee on the floor to hold your weight. Now really straighten your plank by contracting the abs as if you're doing a crunch, and pull your shoulders and head back. Elbows point out about 45 degrees from the torso. At the bottom touch with your chest(because you're keeping your head and shoulders pulled back so well.) At the top push the torso up through the shoulders toward the ceiling(scapular protraction.)
- Lunges and Step Ups: Moving between one leg forward and one leg behind is the foundation of running and carrying. Some variation of this really should be part of a strength training program.
- Turkish Get-Up plus Kettlebell Swing: Between the two you get up, down, back, front, slow and fast.
- Dumbbell Snatch: One thing the five exercises above don't include is developing power, which is exerting force with speed. A dumbbell(or kettlebell) snatch covers lifting a weight from the ground to overhead and adds power development.
- Suspended Row: Hanging with the feet on the ground under gymnastic rings, TRX, or even a racked barbell while rowing requires the body to work to maintain alignment as you pull. Like an inverted push-up.
- Think in terms of general movements and directions first, then pick a set of exercises that includes all of them.
- It's good to involve as much of the body in an exercise as possible, but make sure you're not limited anywhere but the target movement or area. For example, you can squat far more than you can curl, so a "squat curl" is useless.
- Always use proper form. This reduces chances of injury, makes the exercise more effective, and improves the ability to have good form.
- Kettlebells work just as well as dumbbells for these exercises.
- Use enough weight or resistance to challenge yourself. If you can do around 8-10 clean reps, make the exercise harder. If you're not getting winded and sweaty, make the exercise harder. If you can talk to someone or watch TV while doing the exercise, make the exercise harder.
- Don't be afraid of exercising on your own, but consider professional instruction.
In closing, remember that a real program has more than 5 exercises. Some variety is good to insure nothing is missed or overdone, and just to keep your workouts interesting. Keep in mind the principles I have described, and whatever exercises you pick will likely help you get stronger and improve how you move.
For more about picking exercises, see my earlier article Gravity, and the Ups and Downs of Weight Training