PT on the Net Research

Pattern Overload - Part 1

When you wake up in the morning and roll out of bed, do you have nagging pain in your shoulders, knees or back? Do you compare your body to an old truck that still runs pretty well, once it’s warmed up? The times you show up at the gym without wrist straps, knee wraps or your lifting belt, do you immediately think, "Man, this is going to be a rough workout?" If you answered "yes" to any of these questions, chances are you are suffering from pattern overload.

Pattern overload describes injury to soft tissues resulting from repetitive motion in one pattern of movement or restricted movement in one or more planes of motion. Although pattern overload is much more common in an environment such as machine training, which restricts freedom of motion, many workers and athletes who were unrestricted in their training movements also experience pattern overload.

This two-part article series will help you to determine if you or your clients are experiencing pattern overload in your training programs. Part 1 will discuss the causes of pattern overload and how machine training is one of the main contributors to it. Part 2 will take you through the overlooked effects pattern overload has on our joints and neuromuscular control and will provide tips for avoiding pattern overload in your training programs.

Causes of Pattern Overload

Pattern overload results primarily from an inability to properly load share; being isolated or restricted to a specific motion with loss of movement freedom in one or more planes; or over use of any given pattern of movement, regardless of freedom of joint motion.

Inability to Load Share

The human body is highly intelligent and remarkably efficient. To protect itself from unwanted injury the body will naturally sequence the recruitment of muscles to provide optimal load sharing across as many muscles and joints as possible. For example, when performing a bent-over row, the body will select the appropriate motor sequence to divide the load among all the pulling muscles. This allows each working muscle to make its maximum contribution when most favorable with regard to optimal length/force and length/tension relationships.

An example of faulty load sharing can be witnessed in those individuals who have been taught to adduct their scapulae prior to initiating a pull with the lats and other muscles. This faulty motor sequence disrupts load sharing by first recruiting the scapular adductors, shortening them beyond the range of their optimal length/force and length/tension relationships, which then leave the scapulohumeral musculature to perform the remainder of the work. This often leads to strain and trigger point development of the teres major, teres minor and infraspinatus muscles, or otherwise known as pattern overload.

The athlete who regularly performs pulling exercises in the manner described above will likely have a shortening of the scapulohumeral musculature which eventually leads to faulty scapulothoracic rhythm. The result is scapulae that rotate prematurely during all pulling or abduction movements. Over time, this results in stretch weakness of the middle and lower trapezius and rhomboid musculature. Individuals with this type of dysfunction will present themselves clinically as experiencing pain between the shoulder blades and often demonstrate reduced range of motion in shoulder abduction, internal rotation and shoulder flexion.

Through careful observation while training in the gym, you will notice that athletes fitting the movement pattern described above chop their pulling movements into segments. The pull is usually initiated rapidly, favoring use of the now lengthened scapular adductor muscles. The pulling motion is terminated after 60 to 70 percent of the normal pulling range because the optimal working range of the short/strong scapulohumeral muscles and now lengthened scapular adductors has been reached; the scapular adductors are not weak, per say, they are strong at the wrong time.

This pattern of overload , and many others can be seen during many exercises commonly performed in the gym. Although it may take a skilled therapist or corrective exercise specialist to identify many of them, it is safe to assume that your average gym rat or pocket calculator physical therapist with a wild new idea about how to perform an exercise is not going to improve upon "Mother Nature." It has taken millions of years of natural development in the central nervous system (CNS) and peripheral nervous system to develop recruitment patterns that provide optimal load sharing. To test my theory, I consulted some of the oldest known experts on pulling, climbing and exercise (Figure 1). They told me, "if the body works, don’t try to fix it!"

Figure 1

Isolation of Movement by Restricting 3-Dimensional Freedom

If you are a bodybuilder, your primary mission is to make your muscles BIG! Even though building bigger muscles is far from a new concept, using machines to build bigger muscles is a new concept that the body may not always appreciate. To illustrate my point, consider Earle Liederman’s book Muscle Building , published in 1924. In his book, Liederman does not show a single exercise being performed on a machine with a fixed axis of rotation.

It was 58 years later that Bill Pearl’s book, Keys to the Inner Universe , was published. Here, we began to see a transition from pure free weight training to the periodical use of Universal machines, although the book is predominantly free weight exercises.

Jumping forward only four years to 1986, we can see another progression in the use of machines in Bill Pearl’s Getting Stronger . Pearl now includes significantly more machine exercises, including drawings of machines that are of the Nautilus family, equipment most of you will recognize as the beginning of the machine era. Although modern publications continue to share a similar variety of machine and free weight exercises for bodybuilding, a quick visit to the gym makes it clear that the percentage of machine exercises being performed is far greater than free weight exercises.

For most women, avoidance of free weights is driven by the fear of getting too BIG. For the average male going to the gym, there is little instruction on the use of free weights; in fact, there is beginning to be a shortage of free weights, period. I was recently in Venice, Italy, where the heaviest dumbbell I could find in two gyms was 25 pounds and in the only other gym, the gym for bodybuilders, the biggest dumbbell was 50 pounds. Even in the US, there are an ever-increasing number of gyms opening up with NO FREE WEIGHTS!

When asked, gym owners site "safety" as the main reason they don’t provide free weights, or in many cases, why they have such a sparse selection of free weights. To appreciate and share my concern for the lack of functional exercise apparatus, one must have a technical appreciation for what it actually takes to make an exercise functional. Although functional exercise principles are beyond the scope of this article, Pattern overload is one of the ills that directly results from exercising or stressing the body in ways it was not designed for; it’s kind of like taking a sports car off roading in the woods!

Overuse of Patterns of Movement

The terms repetitive stress injury (RSI) and cumulative trauma disorder are commonly used in a physical therapy or medical practice to describe tissue breakdown and injury due to repetitive exposure to a particular movement. These injuries are common among athletes, musicians, workers who perform data entry and assembly line workers. Pattern Overload describes RSI in the athletic performance and conditioning environment.

Pattern Overload is a major source of injury with amateur and professional baseball pitchers, quarterbacks, tennis players and golfers, to name a few. In fact, Schmidt states that a professional quarterback throws approximately 1.4 million passes and a professional basketball player shoots roughly 1 million baskets in their careers. Pattern overload is also one of the primary sources of injury among the swimmers and distance runners I treat clinically.

Whenever someone performs, conditions and/or trains using predominantly one pattern of motion, or has poor motor skills in a given pattern of motion, the risk of injury to the respective working tissues is elevated. To avoid pattern overload in athletes performing repetitive motions, the conditioning coach and/or therapist must be careful not to prescribe exercises that serve to load weakened tissues unless there is specific therapeutic intent and sound rationale for such training.

For example, the in-season tennis player coming to the gym to condition for tennis (a sport of high-speed lunging) may very well have a significant degree of breakdown in the working tissues from practicing and competing alone. Should that athlete opt to, or be directed to perform high volume or high-intensity lunging exercises in the gym, the chances of sustaining injury to the knee extensor mechanism and ligaments, hamstrings or low back increase significantly.

The same scenario can be frequently seen in the throwing athlete, who may be suffering from a mild anterior instability of the shoulder joint. Upon arriving at the gym, the coach often includes heavy bench press and other specific exercises such as medial shoulder rotations on a cable machine. If the athlete has any degree of pain or inflammation in the joint, there is likely to be a corresponding deficit in stability. Continuing to perform exercises which load the same tissues that were insulted during practice and competition will only serve to reflexively inhibit local stabilizers, encouraging Pattern Overload (the exact mechanisms are explained in Part II of this article). This commonly results in bench warming time for both amateur and professional athletes.

To avoid this more dynamic, multi-dimensional pattern overload, care must also be given to assure that the athlete/individual have adequate functional stability to perform the movement pattern of concern. Today, with the massive increase in the number of people working in a seated position and our overindulgence with machine training, there is a tremendous lack of movement skill in the population at large. This means that much more attention to detail must be applied to learning, teaching and execution of seemingly common free weight exercises and movement patterns.

Another underlying cause of pattern overload is poor or non-existent periodization of any given training and conditioning program. In addition to periodizing general stressors to the body, care must be taken when writing programs to execute exercises in the correct order. Some general rules for organizing exercises in a program are:

The only exception to these guidelines is when an elite athlete is being trained by a professional coach trained in the science and practice of strength and conditioning.

Bodybuilding Machines and Pattern Overload

Now that we have seen how and why pattern overload occurs, let’s delve deeper into machine training and how overuse and/or abuse of this type of training greatly increases your chance for developing pattern overload.

To appreciate why machines have become a primary modality for building muscle, we must explore the concepts of neuromuscular isolation and intramuscular training.

Neuromuscular Isolation and Intramuscular Training

To better appreciate the concept of neuromuscular isolation, we must consider that at any given moment, the human body has a finite amount of neurological energy with which to drive it’s population of approximately 250,000,000 muscle fibers. To help you appreciate the importance of the neuromuscular isolation concept, consider your body as though it were a car. In a car, the electrical system is dependent upon the battery for it’s primary energy source and the alternator is responsible for recharging the battery. In our body, the CNS is analogous to the car battery and our heart is the alternator; the heart produces some 2.5 watts of power, which is 40 to 60 times more electricity than the brain.

Figure 2

Neuromuscular isolation is what it takes to produce optimal intramuscular training. When trying to build a muscle, it is necessary to recruit as many of the available motor units feeding that muscle as possible. The beginner may only be able to recruit 60 percent of his or her available motor units, yet with training may be able to achieve the ability to recruit up to 85 percent of available motor units (see Figure 2).

When you perform any functional compound exercise (performed unsupported while standing) (see Figure 3), you are using virtually every striated muscle in your body. Using the above analogy as an example, this is like having the lights, radio, heater, windshield wipers, defrosters, cell phone and cigarette lighter all running in your car at once. This produces a massive electrical drain!

Figure 3

When attempting to build a muscle for the purpose of bodybuilding, it is advantageous to isolate the muscle, with minimal activation of other muscles. This leaves more energy for the working muscle, improving your ability to recruit the relevant motor neurons, just as turning the radio or heater off in a parked car will allow greater illumination by the lights.

As you increase your ability to recruit more motor units and more muscle fibers respectively, it is obvious you can lift heavier weights. Heavier weights means more tension in the working muscle and a greater stimulus for anabolic adaptation. Perform intramuscular isolation training for a couple years on each of your major muscle groups and "presto," you look like a bodybuilder!

Problem with Isolation Machines

This sounds so simple you might ask, "So what is the problem?" Unfortunately, with the exception of a select group of machines, machines in general limit the natural movement of the body. I am sure you are all aware of the fixed axis of a knee extensor machine, the hamstring curl machine, the pec deck, and even the guide rails of a leg press. Unfortunately, these machines do not allow the body’s nervous system the freedom it needs to protect the working joints and relevant soft tissues from injury. This is particularly important when considering that when lifting weights in an isolated manner, loads in working muscles, tendons, ligament and joint structures can become very high.

To illustrate my point, look at Figure 4, which compares the natural bar path during a free weight bench press with that of a Smith machine bench press. What is important to realize with regard to free weight training is that if you were to film someone for as many repetitions as they could possibly perform in one set, at any intensity level, they would never produce the exact same bar path two times in a row! In fact, if you review research on elite Olympic lifters, you will find that not only does the bar path change slightly each time they lift, no two lifters produce the same bar path when executing the same lift.

Figure 4

The scientific concepts of neuromuscular isolation and intramuscular loading make logical sense with regard to building muscle and therefore fuel the bodybuilding industry’s reliance on machines. However, strength coaches and therapists have only recently begun to acknowledge a strong correlation between machine training and musculoskelatal injuries. Therefore machine training, if used at all in a bodybuilding or training program, needs to be periodized and well-structured in order to avoid the commonly seen pitfalls of pattern overload.

I hope you have found the information in this article helpful and have learned about some of the damaging effects pattern overload can have on your training program and training career! Check out Part 2 where I discuss the detrimental effect pattern overload has on your joints, ligaments and joint capsules, and I give tips on how to avoid pattern overload in your training programs.


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