Repetitive stress injury (RSI)
Repetitive stress injury (RSI), also known as overuse syndrome, is a gradual build-up of damage to the tissues resulting from repetitive movements and/or overuse. Carpal tunnel syndrome is a famous example, but far from the only type. We like to think of RSI’s as resulting from normal motions done in excess, but they can also stem from abnormal or compensated motions that require far less repetition. RSI’s result from what it often referred to as the Cumulative Injury Cycle.
The Cumulative Injury Cycle
The Cumulative Injury Cycle is essentially the effect that acute injury, repetitive trauma, and constant pressure or tension has on nerves, muscles, and bones. It is described as having six basic phases to it: tissue trauma, inflammation, muscle spasms, adhesions, altered neuromuscular control, and muscle imbalance. Let’s take deeper look at each phase.
- Tissue Trauma: Tissue trauma can refer to both trauma sustained via a single event and that accumulated over time via micro-tears, contractile tension, etc.
- Inflammation: Any tissue trauma can lead to inflammation of the traumatized area. This inflammation can lead to pain, spasm, compensation and can begin the adhesion process. Several factors can exacerbate the inflammatory phase, such as smoking, diabetes, thyroid deficits and the hormone changes associated with hysterectomy, excessive body weight, and pregnancy.
- Muscle Spasm: Muscles spasm to protect the injured area. These spasms can increase tissue tension and decrease circulation, both of which feed into the creation of adhesions. They also restrict motion, creating a need for additional movement compensation.
- Adhesions: Adhesions form in response to excess tissue stresses such as tension, friction and compression, as well as inflammation. These adhesions restrict motion, lead to compensated motion, and lead to increased tissue stresses in adjacent areas, further feeding into the cycle.
- Altered Neuromuscular Control: In response to adhesion, pain, muscle inhibition secondary to inflammation, and other factors, muscles and joints move in sub-optimal ways. Altered muscle recruitment patterns and muscle firing sequences are typically observed. As with adhesions, this can cause increased soft-tissue stresses both locally and in neighboring areas.
- Muscle Imbalance: Muscular compensation patterns can develop with some muscles displaying an over-facilitation and others showing inhibition.
The Cumulative Injury Cycle is called a cycle for a reason. Each phase perpetuates the others and one can “enter” the cycle at any phase. To understand how we can avoid finding ourselves trapped in this cycle due to RSI, it helps to understand the Law of Repetitive Motion.
The Law of Repetitive Motion
The Law of Repetitive Motion is expressed as an equation: I=NF/AR. “I” represents the total insult to the tissue, “N” is the number of repetitions, “F” is the force, “A” is the amplitude of motion, and “R” is the rest interval between repetitions. The basic gist of the law is that increases to the number of reps and the force of each repetition INCREASE tissue stress, whereas increases to the amplitude (range) of a motion and the rest interval between repetitions DECREASES tissue stress. To decrease our risk of RSI from a particular activity, we should focus on avoiding small, repetitive motions, performed with little to no rest between, under load. Adding rest doesn’t necessarily mean taking a break. It could also mean varying how we do the motion to avoid frequent stresses to the exact same areas. Increasing the amplitude could be something as simple as typing on an old-school mechanical keyboard instead of a low-profile digital one where the key presses are shorter. How we can best apply the principles of the Law of Repetitive Motion to any given activity is specific to that activity. Repetitive motions can’t always be avoided, but they also don’t have to result in RSI. It’s just important to understand the concept of I=NF/AR so we can begin to modify and mitigate our repetitive motions as needed.
What Can Be Done?
While understanding the Law of Repetitive Motion can be key to preventing RSI, it may not be enough to help you with one you already have. To do that, you need to break or interrupt the Cumulative Injury Cycle. At The Body Mechanic, we have tools for addressing ALL phases of the cycle. Active Release Techniques (ART) is our go-to tool for adhesions. We use neuromuscular and neuroenergetic techniques for muscle imbalance, spasm and altered neuromuscular control, and we use class IV laser for inflammation and tissue trauma. Combined with mitigation techniques based on I=NF/AR, this approach has proven very effective over the years.
In terms of what you can do yourself, it’s important to be mindful in your movements throughout the day. Recognize the potential for repetitive stress injury so you can make any necessary modifications. Prevention is key because, once you’re in the Cumulative Injury Cycle, it can be difficult to break.