Why Soft Tissue Injuries OccurResearch has shown that up to 80% of runners are injured every year with most injuries being at the knee. (Van Gent et al., Clin J Sport Med. 2009.) Majority of these injuries are due to soft tissue overload. Other factors include flexibility, range of motion, strength, alignment, shoes, surface, etc. Soft tissue includes structures such as muscles, tendons, and ligaments. The body and soft tissue structures will adapt as long as the applied stress is not greater than it's capacity to adapt. The Running Clinic has defined Load and Frequency below. Load on a tissue is function of the forces applied in:
- Number of repetitions or time of stimulation
- The time between repetitions
- Number of workouts per week.
Minimum ThresholdThere is a minimum threshold to meet in order for the body to adapt. Think of training for a marathon. We can't go from zero to 26 miles in a day. We have to train 3-4 months gradually for our bodies to adapt over time to running 26.2 miles. Stress (load and frequency) on soft tissues encourages remodeling which leads to adaptation, strength, and endurance. The Running Clinic terms the zone below this line as the "Un-Adaptation" zone.
Our soft tissues have a maximum threshold of stress applied for adaptation. We go over that threshold, we can no longer adapt, our soft tissues become overloaded, and we therefore suffer from injuries. The Running Clinic addresses the zone above this line as the "Mis-Adaptation Zone."
This leaves us with the "Adaptation Zone" or a safe zone, between the minimum threshold and the maximum threshold. This is the zone in which we would like to train in order to advance in performance and stay injury-free.
We Are Only as Strong as Our Weakest Link
Since we have two lower limbs and we are running equally on both sides, why does one side get injured?
It's simple. One limb's soft tissue has a lower Maximum Threshold. This is where your sports medicine practitioner enters into the picture. Factors that influence a change in the Maximum Threshold:
- Previous injury to tissue
- Flexibility discrepancies
- Strength discrepancies
- Scar tissue build-up
- Joint restrictions in extremities and spine
- Instability in joints and kinetic chain
- Motor control
- Occupation and self-care activities
Listen to your body!
How do we know we are going over the maximum threshold?
The Running Clinic has determined a simple way to determine when you are going over the maximum threshold line in training. They believe the body will tell you:
- Pain DURING exercise
- Pain remains 30 minutes AFTER exercise
- Increase in morning stiffness day after exercise
Bringing it all together
What does this mean for the injured runner?
- We must train between the minimum and maximum threshold OF OUR WEAKEST LINK to continue to improve and adapt without further injury
- If we want to raise the maximum threshold of a soft tissue, remove the weak link by seeking treatment
- If we want to continue to adapt, we must meet the minimum threshold without going over the maximum threshold
- Pain during or 30 minutes after exercise, or morning stiffness is a good indicator we are going over the maximum threshold