Running Injuries

The 2 main research papers I have used for this blog post consist of a systematic review from 2012 on the major running related musculoskeletal based injuries, and a review article from 2010 on a variety of different factors that may relate to running injuries.

Approximately 10-20% of Americans run on a regular basis.

BENEFITS OF RUNNING

fitness, leading to longevity
long-term exercise promotion

Unfortunately, injury rates are high among runners (approx. 50% of runners get injured on a yearly basis, “…and 25% are injured at any given time.") with an approximated 60% of running injuries caused by training errors

MOST COMMON MUSCULOSKELETAL INJURIES

Running is an extremely repetitive activity, and therefore a lot of the MSK related injuries are because of overuse (the term repetitive microtrauma is a common word in the medical athletic community)
Anything below the knee is seen as the most common place of injury for MSK injuries in runners
In general, the 3 main running related MSK injuries are Achilles tendonopathy, plantar fasciitis, and medial tibial stress syndrome “shin splints”
In ultra-marathoners (whose races ranged from 5-8.5 days) the main injuries also included Achilles tendonopathy as well as patellofemoral syndrome.

SHIN SPLINTS

2 potential reasons
1. The continuous cycle of landing and propulsion in the running movement causes repeated contractions of 3 major muscles (tibialis posterior, soleus, and/or flexor digitorum longus) These muscles all attach to the tibia (your shin) and therefore put repeated stress on this bone creating the constant inflammation and pulling of the muscles off the bone that create the symptoms of shin splints.
2. Because running can be so repetitive and persistent, this may cause reduced capacity for bone to remodel. Constant wear and tear on the shin bone not only from muscles pulling on it, but also from the sheer pounding force of your body hitting the ground (scientifically we call this ground reaction force) may cause this type of cumbersome injury.
Other potential causes of shin splints may include bow legged knees, continuously changing up your running shoes, and interval training.
Overall, it is still unknown what directly causes shin splints

ACHILLES TENDONOPATHIES

Tendonopathies in general are caused by excessive loading.
The continuous load placed on the body during running creates more force than the tendon can tolerate à degeneration à symptoms of pain
Running on sand is probably best to avoid, and distances between 1500m and 5km also may increase risk for Achilles tendonopathy.
The patellar tendon is also commonly injured in runners (jumper’s knee) because of eccentric loads of the quads

PLANTAR FASCIITIS

One of the most common foot injuries, and again it is related to degeneration, this time not of a tendon but rather the fascia on the bottom of the foot.
The most common site of pain in plantar fasciitis and something I really want to get across today so you can be more aware of what to look for is pain at the medial calcaneal tubercle
It makes sense this is a common injury because the heel is the first point of contact when you land on the ground when running. The impact can be up to 3X your body weight, and it’s up to the plantar fascia to absorb and transmit that energy (along with the fat pad in the heel and your foot musculature)
Ageing, and repetitive motion (such as running) may cause degeneration of the plantar fascia or fat pad à injury

PATELLOFEMORAL SYNDROME

Most commonly related with abnormal tracking of the knee cap and the extremely compressive loads created from your quads. These 2 factors à stress on your patellofemoral joint (where your knee cap attaches to the thigh)
In marathon runners it has been shown that running fewer km/week = a risk factor for PFS and that more km and hours trained/week is protective against knee injury.

INJURY FACTORS

MILEAGE

Though it has been found the more mileage run = protection for knee injuries unfortunately it has shown to give more hamstring and thigh issues. Research has also shown that male runners who run more miles in a week (>64 km) are put at increased risk for general running based injury. Approximately 50-72% of the running injuries caused by training errors arise from overdoing it in terms of mileage or a change in training routine. Increases in both running duration (minutes) and frequency (days per week) have been seen as negative factors
note: unfortunately a lot of the evidence on mileage has been done on males, and the limited research on females is conflicting in this manner. It has been shown that female runners who run on concrete have higher injury association, but no association has been found in those running on “harder surfaces, hilly terrain, or running in the dark.”

PAST INJURY

Past injury

ERRATIC TRAINING SCHEDULES

Erratic training schedules

TRAINING SPEED

“…[m]ost studies show no association between training speed and injury risk…”

EXPERIENCE LEVEL

Level of experience in running has had mixed conclusions in terms of running injury.

PES CAVUS

Pes cavus has moderate research indicating running injury risk, it has been linked to PFS, recurrent stress fx and lower limb injury. Unfortunately “…no prospective data indicate that treating cavus feet with arch support, orthotics, or other interventions will lessen running injury risk.”

LEG LENGTH INEQUALITY

Leg Length Inequality has some low level evidence to show that it can be a factor in running injuries

MUSCLE WEAKNESS

Muscle weakness: hip abductors, hip flexors (ex:// ITB syndrome) VMO (re: PFS)
Though not specific to research on running, eccentric training is great for tendons and may reduce injury in the Achilles tendon, patellar tendon, hamstrings, and in relation to PFS

ORTHOTICS

Orthotics have been shown to provide subjective improvement and high satisfaction in those wearing them, and “…several good studies support their use for injury treatment.” It is well known that orthotics “probably reduce the incidence of stress fractures…” They can help reduce symptoms in those with painful pes cavus and rheumatoid arthritis, and are potentially beneficial for plantar fasciitis. Custom orthotics have been shown to be beneficial in PFS and painful pes cavus (2 common running injuries).

BAREFOOT RUNNING

A lot of barefoot running research is based on anthropology and theory, and not a lot of solidified research. The article on barefoot running cited in my references concluded “if it ain’t broke, don’t fix it” as their advice for barefoot running… i.e. if you’re not injured there isn’t research enough to warrant a switch to barefoot running. And if you are injured, it may be beneficial or detrimental to your injury (it’s a toss up).

RUNNING SHOES

In regards to running shoes, a review done on the topic did not show a proven recommendation for “shoe prescription” based on a person’s foot type.

STRETCHING

Research does not seem to back up stretching to prevent running injury, some studies have even shown an increase in injury with stretching. However, research has not changed the views of most sports practitioners and coaches. One of the challenges of research and stretching is that there are many different forms of stretching, so we first need to have a solidified understanding of the most effective form of stretching (i.e. is it ballistic or passive, contract/relax or static?)
Based on research I recommend a stretch that is approximately 30 seconds. Less than a 10 second stretch hasn’t been shown to be effective, and those over 1 min have been shown to be no better than stretches held between 10 sec and 1 min.
There is also debate that maybe stretching after activity, as opposed to before activity, is best.

WARM UP

There is not enough high quality research on warm-up and injury prevention.

TAKE HOME MESSAGE

In the end, we are certain that if we can control training errors (mainly through the variable factor of total running mileage) that this will help prevent running injury. We also know for certain that if you have been injured in the past, you are more likely to get injured again, but how to reduce this risk is not as cut and dry as the statement suggests. Cavus feet and leg length inequality are something that myself, as a practitioner, can look at in terms of potential risk factors for injury. Though you cannot change these anatomical factors, if you know about them you can do your best to improve other more modifiable factors. Though orthotics may reduce stress fracture risk, it is uncertain whether orthotics will reduce the risk of injury in those with pes cavus or a leg length inequality.

REFERENCES:

Fields KB, Sykes JC, Walker KM, Jackson JC. Prevention of Running Injuries. American College of Sports Medicine2010 May/Jun. 9(3):176-82.

Lopes AD, Hespanhol LC Jr., Yeung SS, Pena Costa LO. What are the Main Running-Related Musculoskeletal Injuries? A Systematic Review. Sports Med. 2012. 42 (10): 891-905.

Murphy K, Curry EJ, Matzkin EG. Barefoot running: does it prevent injuries? Sports Med. 2013. 43:1131–8. DOI 10.1007/s40279-013-0093-2