Acute trauma is a sudden and quick stress into the body that causes an injury, such as getting kicked in the shins. Chronic repetitive stress injuries are a slow accumulation of trauma to an area of the body. Injuries that occur over time are harder to understand and appreciate. People often say "how could that cause it, I've been doing it for years?" Exactly!
Think of an assembly line worker installing the passenger side door on a model T Ford. Henry Ford just came out with this concept of an assembly line; a worker would be doing the same job over and over so he could perfect his speed and quality. The worker's job is to place the door on and then turn five screws per door. It is not hard or exhausting work to install the door, only repetitive.
Over 10 years how many doors would the worker install and how many screws would his forearm twist into place? If we took the number of screws and multiplied it by the force to turn the screw we would see an incredible amount of force applied by the forearm. That accumulating force is producing microtrauma and damage to the forearm and may lead to lateral epicondylitis or elbow pain.
Repetitive stress injuries are a function force multiplied by repetitions and by frequency. 50 Newtons of force times 30 repetitions times 3,600 days, 50 x 30 x 3,600 = 5,400,000 Newtons.
More simply stated, repetitive injuries are like adding pennies to a penny jar. Some days you add 15 pennies, some days you take five pennies. Over time there is a tendency to add more pennies than you are removing, and eventually the jar starts to overflow. The overflowing penny jar is your chronic repetitive stress injury. There was not a single event or day that filled the jar; instead the jar became full after an accumulation of days and pennies.
Often people are adding pennies to their jar because of weakness, fatigue, or injury in other parts of their body. In addition to removing existing pennies from the jar, treatment will focus on reducing the amount of pennies you are adding every day. The amount of repetitive stress placed upon your body can be dramatically reduced by changing postures and habits. For example, a person with low back pain may be uncomfortable sitting, which causes them to slouch at the computer. The slouching was contributing to neck pain and headaches. Improving the lower back pain will allow a person to sit with better posture and strain the neck less during the day.