Tendon Injuries: What a pain?
Tendon injuries account for a large number of injuries both sport and work related. Tendon’s are the connective tissue that bridge muscle to bone and are abundant near joints. As the muscle contracts and creates force, the force is transmitted through the tendon and the tendon pulls on the bone which moves the joint. Tendon injuries often occur when they become overloaded (working overtime). In fact, over 50% of sport related injuries are caused from overuse.1 Initially, inflammation sets in but most evidence suggests inflammation only lasts during the acute stages of injury. An overloaded tendon over time results in microtears and disruption of fibers resulting in that painful achy sensation when the tendon is in use. Unfortunately or fortunately, microtears, inflammation and disruption of fibers can only be detected with advanced tissue studies (not something any of use want to subject our tendons to).
Exercises have consistently shown to improve tendon pain and are capable of realigning disorganized, unparallel tendon fibers (a.k.a. pulled pork).
Tendinopathy is a broad term used to described a wide variety issues with tendons.1 I like to describe chronic overloaded, overused tendons like pulled pork: a stringy chaotic mess. Healthy tendons, under the microscope, appear parallel and are best suited to handle load. The pulled pork variety is no longer capable of handling the force (or load) from muscle contraction. These pulled pork fibers weaken and eventually failure of the tendon occurs (i.e. The dreaded Achilles tendon rupture). According to Jill Cook and her crew, microtrauma to the tendon is caused by repetitive abnormal loading.1 I understand this in a biomechanic sense as the way you’re transmitting force (or “loading”) through the tendon is not uniform and therefore parallel fibers cannot handle the load. One of the big question in the research world is: If you load muscle or bone they get stronger then why do tendons become weaker with load? Maybe its related to blood supply. In general, the tendons that are likely to become pulled pork do not have any blood supply (known as avascular). This means when a overload occurs and microtrauma begins, poor healing is the outcome due to poor blood supply. To make matters worse, over the long period an increase in blood vessels occurs (called neovascularization) in a tendon that is supposed to have relatively little blood supply. Once blood is in tendon, the inflammatory mediator called substance P makes life miserable for the tendon. After all this fancy explanation I realize I have not once commented on pain. That’s because we don’t really know what causes pain in the tendon. Pain is really the limiting factor in tendinopathy. Confusing for anyone. It is possible the pain comes from the increase in blood vessels but the jury is out on this.
What can we conclude so far? Loading the tendon is bad right? Hold on a second. Unloading the tendon is also very bad. After all, the tendon’s main goal in life is to transmit load from muscle to bone and create movement. So not loading the tendon can lead to further tendinopathy.1 Remember it’s abnormal loading that causes the issue. Here’s an example: A runner purchases new shoes and cant wait to get out the first 100 miles in the fancy new kicks. There is a sharp increase in volume of running (overload from overuse) with new biomechanics from new shoes leading to swelling and pain on the achilles tendon near the ankle bone. This is an acute situation and the runner is in pain so takes 3 weeks off running. Over the three weeks, the tendon has minimal loading and disorganization begins. The runner returns to running (most likely same mileage) and overloads the tendon again. Repeat this process for a few months and we’d see the pulled pork tendon under a microscope. All because of overuse with abnormal load. Now let’s go back and change the outcome slightly. The runner is patient with breaking in new shoes only using them for small mileages and when she/he notices the inflammation and slight pain in achilles, realizes the overload and heads to the gym for instruction on resistance training instead of running.
The key then is to remove the abnormal overload and increase proper loading through proper exercises. Exercises have consistently shown to improve tendon pain and are capable of realigning disorganized, unparallel tendon fibers. There is some evidence that manual therapy in the form of soft tissue therapy can help with pain however there is no evidence to show soft tissue therapy actually changes tendon fiber orientation. So if you’re suffering through tendon pain, don’t despair there is effective help out there. It’s just counter intuitive to what most people think. For more information on strength training head over to Evolve Strength or send me an e-mail.
Rees, J. D., Maffulli, N., & Cook, J. (2009). Management of tendinopathy. The American journal of sports medicine, 37(9), 1855-1867.
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About the Author: Dr. Piper
Dr. Piper is the only sports specialist chiropractor in Edmonton. In addition to joining the Evolve Strength team, he works alongside sports medicine specialists, orthopaedic surgeons, radiologists, physiotherapists and athletic therapists at the Edmonton Sport Institute helping athletes of all levels achieve their goals and recover from injury. Dr. Piper has an extensive post graduate education in rehabilitative medicine and sport sciences