Pattern Overload
Pattern overload describes soft tissue injuries caused by repetitive motion in one pattern of movement or restricted movement in one or more planes of motion. It is most common when using predominantly machine training which restricts movement to one pattern. But it is also common in a work or sporting environment where a person performs the same pattern over and over eg assembly line worker, swimmers, distance runners.
Pattern overload results mainly from the following factors:
- Inability to share the load
- Being isolated or restricted to a specific pattern with loss of movement in one or more planes
- Overuse of any given pattern
- Inability to share the load
The human body protects itself from injury by sequencing the recruitment of muscles to share the load over as many muscles and joints as possible.
This allows each working muscle to make its maximum contribution at the optimal time with regard to biomechanics and neurological demands of the movement.
Example of a faulty pattern leading to overload
Adducting the scapulae prior to a pull movement with the lats and other muscles. This disrupts the load sharing by recruiting the scapula adductors first. This shortens them beyond their optimal length/force relationship. The scapulohumeral muscles then have to continue the work which can lead to strain of the Teres major and minor and infraspinatus.
- Being isolated or restricted to a specific pattern with loss of movement in one or more planes
In unrestricted movement, the body never performs the movement in exactly the same way. As one group of muscle fibres or motor units gets fatigued, the body recruits a different set of muscle fibres/motor units to continue the movement. This changes the movement pattern slightly and protects muscles, tendons, ligaments, joint capsules etc from overload and injury.
However, in a controlled movement pattern, the body has less ability to recruit different muscle fibres/motor units. This means the load on the other soft tissue structures doesn’t change, leading to overload, fatigue and injury.
Example: performing a chest press movement on a Smith machine is a controlled movement pattern as the bar can only move in the same plane of movement every time. This increases wear and tear on the same structures each repetition. Contrast this to doing a chest press on a bench with a free barbell where the bar is free to move in different planes and angles etc. Take this a step further and do chest press with dumbbells or lying on Swiss ball.
- Overuse of any given pattern
This occurs when performing the same overall pattern of movement repetitively such as in swimming, long distance running and baseball pitching. This also occurs in some work environments such as data entry and assembly line workers etc. This type of overuse commonly leads to injuries known as repetitive strain injuries or RSI.
Avoiding pattern overload
To avoid pattern overload, a person or coach etc needs to make sure they are not prescribing a conditioning program that further loads already weakened tissues. It is also advisable to add in some cross training to give the loaded tissues a break from the same movement pattern. Adequate stability to perform any pattern, including a repetitive pattern is also very important. As is proper periodisation of loading.
Conclusion
Pattern overload is a common source of musculoskeletal injury. To avoid pattern overload make sure you do the following:
- Periodisation – of load, volume of work, intensity, rest periods
- Do combinations of training methods and movement patterns ie cross training
- Always remember to work on inner core stability
Yours in good health
Brad Corbett
Osteopath
Personal trainer
Holistic exercise & lifestyle coach