by Andrew CSCS, January 18, 2018
In the gym, we workout to see results; to reach our goals. Once we find a good routine and rhythm in our training, few things are more frustrating than when an injury occurs that impedes our ability to continue on the path to better health and overall quality of life. However, when an injury occurs, like a sprained knee ligament or dislocated elbow, there is a silver lining and a way to make the most out of this situation without having to put your training routine on pause. That being said, depending on the injury, if your doctor or clinician tells you to stop all physical activities…. I’m afraid they do have final say.
Based on extensive research and data collection, a scientific phenomenon (scientific theory may be a more appropriate term to describe it) called Cross Education Training has been shown to be a useful method of training to work around injured limbs while still seeing improvements in training adaptations. Because of interhemispheric communication between the right side of the brain to the left side of the body and left side of the brain to the right side of the body we can still expect to see neuromuscular motor unit recruitment in the right bicep when the left bicep is the only side doing work. Based on a meta-analysis of numerous cross education research studies, a 7% increase in absolute strength can be seen in the injured/untrained limb while only using unilateral training on the uninjured/trained limb. Unfortunately, the strength improvements occur based on the increased number of motor unit connections, not based on increases in muscle fiber size (hypertrophy). Therefore, there will most likely be some degree of muscular atrophy.
Just to clarify a few of these “vocabulary” words. Unilateral training refers to single arm or single leg training. For example, alternating dumbbell bicep curls would be classified as unilateral training. Although both arms are being used in a single set of this exercise, only one arm is being trained at any one given repetition during the set. To put this same idea into cross education terms, let’s say the subject had fractured their right ulna and could not train that limb for an extended period of time. In theory, if the subject still trained unilaterally on the left/uninjured limb, there would still be an average of a 7% increase in the untrained/right limb.
The good news is that there is still a reason to come to the gym even with certain injuries. No more excuses… The bad news is that you are still injured and should always use caution when exercising avoiding anything a doctor or clinician has told you not to do.
Timothy J. Carroll, Robert D. Herbert, Joanne Munn, Michael Lee, Simon C. Gandevia
Journal of Applied Physiology Published 1 November 2006 Vol. 101 no. 5, 1514-1522