There are a plethora of reasons as to why we get injured.
History of previous injury to the area, lack of sleep, emotional stress and improper conditioning, these are but some of the many factors that can predispose you to injury.
However perhaps the structure that gets injured is dictated by what it’s trying to protect.
Could it be that a muscle may tear preferentially to protect an underlying structure that is more critical to our basic human needs. Is there a certain hierarchy in the body that exists that means a muscle may preferentially tear or sacrifice itself to protect an underlying structure?
I was first introduced to this concept by one of my first Physio mentors Paul Lew who suggested that perhaps a reason why hamstrings were so prone to injury was that they sacrifice themselves preferentially to protect the sciatic nerve. He reminded me that the sciatic nerve would not heal to the degree of a muscle after injury and would cause a significantly greater impairment to the individual.
Whether this is the case is not the point of this discussion, however it open my eyes to the fact that due to the bodies ability to control muscular tone from a central nervous system level, there is the possibly of an innate protective mechanism that is built-in to protect structures that take longer to repair or may not repair to the same functional levels as what a muscle can.
3 days ago it became personal after tearing my medial gastrocnemius muscle in an innocuous incident playing soccer.
In the lead up to this event I was the fittest I’d been in 15 years, so physical conditioning was not the reason. However, the preceding 3 to 4 days had been mentally and emotionally stressful with family and business matters to attend to, and to top it off I was short on sleep. All proven predisposing factors to injury.
But it led me to thinking why did my calf muscle tear? How could sleep and emotional stress cause a calf injury?
What was the calf muscle protecting?
Did the structure it was protecting have anything to do with fatigue or my mental state.
The answer quite possibly could lie in the Lymphatics.
Shinaoka et al. (2020) demonstrate in their brilliant article the extensive and independent array of lymphatics that supply the lower leg.
As a short summary the lymphatics run alongside the venous and the nervous systems and are primarily involved in removal of metabolites, inflammation and coordinating the immune responses of the body.
There is 15 L of lymphatic fluid that circulates at any one time, and the lymph nodes serve as the major junctions for the lymphatic vessels are the home of the B and T cells which are major players in our immune response. This short detail is simply to illustrate how important this relatively unknown system is.
Shinaoka et al. (2020) show in their cadaveric study that the Postero-medial and antero-medial (Picture 1) lymphatic array of the calf sits within and supplies the area of the medial gastrocnemius and plantaris.
Is it possible that three nights of reduced sleep, relative inactivity and stress (which is known to increase circulating cytokine (inflammatory) formation led to a build up of lymph within the antero-medial lymphatic complex of my right triceps surae (calf) that was the final trigger to me tearing my gastrocnemius?
It’s an unknown factor however we shouldn’t stop thinking of the reasons why such effects of sleep and stress can predispose us to musculoskeletal injuries but go further and investigate that quite possibly they are protecting a deeper more important structure such as the lymphatics underneath.
This then increases the scope of what are “Injury Preventative strategies”. Perhaps this is an argument to include lymphatic massage or self-tapping? Or does this explain a benefit of dynamic movement around the draining inguinal lymph nodes of the lower limb?
Whilst a great deal of further research needs to be done to be sure of a causative link, such strategies would be useful particularly at times when stress or sleep deprivation are high as may be perceived or measured on athlete wellness monitoring scales.