PRINCIPLES OF EXERCISE DESIGN - HOW TO DESIGN YOUR OWN STRENGTH TRAINING EXERCISES

By Rick Morris

INTRODUCTION

Your goal when engaging in resistance training exercises will be to strengthen a specific muscle or a specific motion. There are many exercise books that will show you standard exercises to strengthen muscles. Because of the mass distribution of these books, the exercises are generic in nature and do not take into consideration your individual goals or differences in body size, type and anatomical characteristics.

Instead of blindly following the "standard" exercises, consider designing your own exercise that is tailored to your individual anatomy and your specific goals.

You can use the following six steps to design any exercise.

What joints and muscles are involved?
What motion and direction of motion is involved?
Where is the resistance coming from?
What body position do you need?
What is the appropriate range of motion?
What joints need to be stabilized?

WHAT JOINTS AND MUSCLES ARE INVOLVED?

The first step in designing an exercise is determining the joints and muscles involved in the motion. Before you begin to design an exercise involving resistance, you must determine what joints and muscles are being used. Each exercise you design will target either a specific muscle, muscle group or a specific motion. If you are targeting a specific muscle or muscle group, you must determine which joints are involved. If you are trying to strengthen a specific movement or motion, you must determine which muscles and joints are involved.

All exercises are either single joint or multi-joint movements. A biceps curl is an example of a single joint exercise. The only movement of a property executed biceps curl is at the elbow joint. A familiar example of a multi-joint exercise is the bench press. In performing this exercise; there is movement at the shoulder joint and at the elbow joint.

A single joint exercise will usually involve only one major muscle (primary mover). A multi-joint or compound exercise can involve two or more primary movers. There can be several muscles that either assist in the movement or stabilize depending upon how the exercise is designed.

As an example, the prime mover in a bench press exercise is the Pectoralis major - the large muscles at the front of your chest. The assisting muscles are the anterior deltoid muscles - the muscles at the front of the shoulder and the Triceps brachi - the muscles at the back of your upper arms. Stabilizing muscles used will depend upon the equipment used. Using a universal style weight machine will take away the need for much of the stabilization. The machine does much of the stabilization for you. Using free weights require you to "balance" the weight and require the use of more stabilizing muscles. This is one of the advantages of using free weights.

WHERE IS THE RESISTANCE COMING FROM?

Resistance can come from gravity, body weight or one of many external forms of resistance. In this third step of designing an exercise, you must determine this direction of resistance.

The direction that the resistance is coming from will determine what type of exercise you design. If you are using free weights or a weight plate type resistance machine, the resistance is caused by gravity. Gravity is pulling the weights straight down toward the ground.

Body weight exercise is also a gravity-caused resistance activity. Your body acts as the weight, which is pulled straight down. Exercise bands, power rods, hydraulic and air cylinder resistance machines can have many different directions of resistance. With exercise bands the direction of resistance will depend upon where the anchor point is. The direction of resistance will be a straight line from the anchor point (where the band attached to an immovable object) to where it attaches to the body part being exercised.

The direction of resistance for hydraulic and air cylinder machines will be a straight line between the point that the moving lever of the machine touches the body part being exercised and the place where the lever attaches to the resisting portion of the machine.

See the article entitled Forms of Resistance for a description of the various sources of resistance.

GETTING INTO POSITION

After figuring out where the resistance is coming from you need to get your body into the proper position to complete the exercise. The first step is to place your body so that the path of motion of the body part being exercised is in the same plane as the path of the resistance. If the resistance is moving horizontally or in a horizontal plane, you should position your body so that the body segment being exercised is moving in a horizontal direction. You must be in a position that will allow you to push or pull in the opposite direction that the resistance is moving.

The bicep curl is an example. If you are using free weights for resistance, the direction of resistance is straight down or vertical. You would position your body so that your lower arm will move vertically when you flex your elbow. You position yourself so that you are flexing upward against the resistance, which is going downward. In other words you are in a standing or sitting position with the weight above your hands. This is a very simple and obvious example, but all exercises are designed using these same steps.

The next step is to determine where other body segments should be positioned. If you are in a standing or sitting position, place your non-exercising body segments so that you have a stable base to work from. If you are lying on your back, position other body parts so that you do not have any excessive curve in your lower back.

The final step in positioning your body concerns the range of motion of the part being exercised. Everyone's ROM (range of motion) is different. Your individual ROM will depend upon your musculature, limb length, flexibliity, charateristics of your connective tissue (ligaments, tendons) and how your joints are shaped and constructed. The starting position of your exercise should not force your joints to the limits of thier ROM At the limit of your ROM your joints are much more susceptible to injury. Make necessary adjustments to your position in order to avoid a starting point that is at the limit of your ROM.

RANGE OF MOTION

Range of motion does not mean how far the resistance will travel. It is determined by the characteristics of the muscle and joint involved in the exercise. There are three primary ranges of motion. They are passive range of motion (PROM), active range of motion (AROM) and resisted range of motion (RROM).

You must design your exercise so that it moves through its appropriate range of motion. The appropriate range of motion does not necessarily mean its full possible range of motion. It is not always necessary for an exercise to travel through its full possible range of motion. It may, in fact, cause injury if excessive range of motion is used. Do not use any more ROM than is necessary to strengthen the motion desired.

Passive range of motion (PROM)

PROM refers to how far a joint will move before it meets with resistance. This is usually tested by having a partner manipulate the joint through its full range. PROM is limited by musculature, shape and construction of the bones of the joint, flexibility, and characteristics of the connective tissue (ligaments, tendons). You should never try to force your joints past their PROM in any exercise.

Active range of motion (AROM)

AROM refers to how far you can move your joints, with no resistance, using only your own muscle power. For instance, if you try to extend your arm behind your body, you can only move it a short distance. That is the limit of your AROM. If someone tried to move your arm farther back, they could move it a little farther. That would be your PROM. AROM is limited by the same anatomical characteristics as PROM and also by your individual ability to move the joint with your own muscle power.

Resisted range of motion (RROM)

RROM is similar to AROM. The difference between the two is that RROM is the range of motion with resistance or when you are performing the exercise. RROM is limited by the anatomical characteristics, your individual ability to move the joint under resistance and by the resistance being applied.

Conclusion

Remember that it is not necessary to move through the entire possible range of motion. Look at the movement you are trying to strengthen. It rarely requires a large range of motion. If you are simply trying to strengthen a muscle, move only as far as you can without putting stress on the ligaments and bones of the joint. More is not necessarily better and may be less effective as well as less safe.

STABILIZATION

You must prevent motion other than that of the muscle or movement being exercised. There are several points of stabilization that you should concentrate on.

Spine

You should stabilize your spine during any exercise that you do. Contract your abdominal muscles and concentrate on maintaining a neutral position with your spine. Do not arch your back or slouch forward.

Adjacent joints

in order to isolate the muscle being exercised you should concentrate on stabilizing the joints closest to the moving joint and closest to the source of resistance. There is sometimes a great tendency to move these joints. Keep them stabilized to insure an efficient and safe exercise.

Multi-joint exercises

Functional strength training involved multiple moving joints. This type of exercise improves strength involved in specific athletic movements, such as running, jumping and swinging. When designing functional strength training exercises, you should stabilize the muscles supporting the movements. Most functional exercises for runners involve multiple movements of the legs and arms, while the truck is stabilized and provides support.