Ten Requirements for a Properly Performed Exercise

Everyday people walk into a gym and perform the latest exercises they see in a fitness magazine. Unfortunately many of these exercises do not produce much in the way of a thorough inroad into the muscle, which is needed to produce a stimulus intense enough to spark the muscular growth mechanism.  It is vitally important when choosing the exercise or tools you use to lift weights, that you consider the following ten requirements for a properly performed exercise:

Rotary Resistance

Rotary form exercises are those that are performed using a single joint and move in a rotational fashion such as a bicep curl.  It goes without saying that an exercise that provides resistance through the entire range of motion would be more effective than one that does not.  As we compare the use of a dumbbell or barbell curl and the use of a selectorized machine it becomes obvious that the dumbbell or barbell does not provide constant resistance at the point of full flexion or extension.  The machine however, due to the use of properly designed cams, does provide resistance at these points.

Direct Resistance

In many barbell exercises the amount of resistance that can be used is limited by the strength of weaker intermediary structures, preventing the targeted muscular structures from being loaded as meaningfully as possible. In a properly designed machine, the resistance can be applied directly to the target muscles without going through a weak link, which allows them to be inroaded more efficiently. A good example of this would be a leg press vs. the barbell squat.  The weaker link in the barbell squat is the low back, which is removed from the equation via the leg press which loads the resistance through the hips and gluteals.

Variable Resistance

A person's usable strength changes from position to position during any movement due to the effects of friction, myofibril congestion, virtual cam effects resulting from the changes in tendon insertion angles and other factors, as well as changes in leverage resulting from the changing angles of the involved bones during multi-joint movements. This is referred to as ones strength curve.  The resistance provided by free weights or machines can also vary over the range of motion of an exercise due to changes in leverage or torque. This change in resistance over the range of motion is what is referred to as the resistance curve for that exercise.  In order to maximize the effectiveness of an exercise these two curves should match as closely as possible which can not be accomplished with the use of free weights due in part to the lack of rotary resistance.

Balance

It is often thought that the need to balance a barbell, dumbbells or the body during free weight exercises requires greater muscular effort and results in greater strength or growth stimulation to the body. This is not true, however, since very little muscular effort is required to balance something.  The need for balance during free weight exercises is actually a disadvantage, since the skill of balancing an object or the body requires a certain amount of focus which detracts from one's ability to concentrate on contraction.

Positive Work

This is the most obvious and most easily understood concept in strength training.  The tools used to exercise must provide positive resistance meaning that your muscles must have resistance applied to them while they move.  Positive work is referred to as the concentric phase of the movement.

Negative Work

The eccentric portion of the exercise is the opposite of the concentric portion.  In order to maximize the potential of a given exercise it must provide negative resistance.  The recent use of hydraulic machines in some facilities does not provide this portion of the movement.  The common cover-up for this gross resistance deficiency is "double positive." For example, the arm machine that addresses elbow function provides resistance to the triceps upon extension and then resistance to the biceps upon flexion, thus permitting either structure to rest during its negative phase.

Full-Range Exercise

An exercise is considered full range if there is resistance in the extended or starting position which is important because it provides pre-stretch and increases flexibility.  Likewise it is important to have resistance in the fully contracted or ending position.  If an exercise lacks resistance in either of these two positions it is not full range.  The only source of full range exercises is selectorized machines.

Pre-Stretch

The pre-stretch technique is a short range, sudden movement in the opposite direction of positive contraction.  This brief twitch invokes a reflex arc that alarms the muscle to activate higher contraction intensity.  This technique is then immediately followed by a smooth, continuous muscular contraction of assumably higher intensity.

Resistance in the position of Full Muscular Contraction

An exercise must provide resistance at the point of full contraction.  In order to understand the importance of this requirement, let’s look at an example.  When performing a bicep curl with free weights, the bicep relaxes in the fully contracted position due to the gravitational pull being in line with the position of the arm.  Inherently the exercise can no longer be considered intense if the target muscle can relax during the exercise.  A properly designed selectorized machine does provide resistance in the fully contracted position therefore machines are superior to free weights because they can provide this very important requirement.

Unrestricted Speed of Movement

One of the most debated and misunderstood concepts is repetition speed.  This debate has, and will go on for years and will be better explained in later articles.  It is necessary however to understand that in order to properly inroad a muscle it is necessary to have unrestricted speed of movement.  The speed of motion in a given exercise greatly depends on the tool one is using during the exercise.  Tools, whether machines, barbells, etc., should not be of such poor quality that you are forced to speed up movement to smooth out friction and compensate for poor design.

The ten requirement were developed and tested by Arthur Jones and his team at Nautilus.  In addition they have been further used as a basis of training by many HIT practitioners over the past several decades.