Running is a popular activity year round but more so with the warm weather, especially here in the NYC area. The benefits of running and exercise are often touted, but are there potential risks? Running has been shown to increase cardiovascular fitness, physical fitness, metabolic fitness and balance. With all these positives, however, there are associated risks. Acute, accidental injuries may always occur, but also overuse injury, which is an established mechanism of injury in orthopedic sports medicine literature. Lower extremity injuries are by far the most prevalent body location in runners. In this issue of ArthroKinetix, we will review the common questions asked and evidence-based answers from an orthopedic standpoint.

What are the health benefits of running?

The American Heart Association and the American College of Sports Medicine recognize physical exercise as important for preventing and managing chronic diseases such as type 2 diabetes and cardiovascular disease. Adults are recommended 30 minutes of moderate aerobic activity 5 days a week or 20 minutes of vigorous aerobic activity 3 days a week. Running helps meet this recommendation and helps maintain skeletal health.

Are there health risks with running?

Short answer is no but there are nuances. Physiology and metabolic changes from running are generally transient and beneficial as opposed to detrimental. Excessive training, however, can lower neutrophils and make athletes susceptible to upper respiratory or other infections. Sudden cardiac arrest is rare event, but occurs in 1 per 184,000 runners, 1 per 100,000 marathoners, 1 per 40,000 college athletes and 1 per ~53,000 tri-athletes. 86% of sudden cardiac arrest occur in men.

What are the musculoskeletal risks of running?

In general 25% to 36% of runners have a associated injury. The majority fall under overuse injury and involve the knee. The strongest predictor for running injury is distance, with more injuries seen over 65 kilometer per week or ~40 miles.

The high ground reactive forces result in the higher incidence of lower extremity injuries. The knee is the most common area of overuse injury followed by lower leg, foot, upper leg, ankle and hip/pelvis. In a retrospective review of over 2000 running injuries the most common diagnoses were: anterior knee pain, iliotibial band syndrome, plantar fasciitis, meniscal injury and patellar tendonopathy.

Is running bad for my joints?

Overall studies have shown that running is not a risk factor for osteoarthritis. A recent meta-analysis found that runners have 50% lower odds of undergoing osteoarthritis knee surgery compared to nonrunners.

What kind of stretching is recommended?

The three types of stretching investigated are static, dynamic and proprioceptive neuromuscular facilitation (PNF). PNF is an advanced form of flexibility training, which involves both the stretching and contracting of the muscle group being targeted. Dynamic stretching has been associated with an increase in performance before power or speed activities but not with endurance. Static and PNF stretching have both been associated with performance deficits but research is limited. Stretching has not been shown to reduce overuse injuries.

Can barefoot running prevent injury?

Minimalist shoes have high flexibility, low heel drop and no stabilization. They provide minimal interference with the natural movements of the foot. Barefoot running is a subset of minimalist running. Running shoes with large heel pads cause an initial near vertical heel strike resulting in as much as 1.5 to 3 times body weight ground reaction forces. These forces are hypothesized to result in higher incidence of running injuries such as plantar fasciitis and tibial stress fractures.

Runners switching from traditional to minimalist running shoes have reported lower incidence of injuries but... there is also an increased rate of injury noted with the transition. With the shorter step length and higher frequency of barefoot running more achilles tendon, calf, and posterior tibialis strains are noted. A higher risk towards metatarsal foot pain and bone marrow edema was reported on MRI within 10 weeks of transitioning.

Am I too old to run?

Age is not considered a contraindication to running. With age, decreases in muscle size (mass) and contractility occur and a more substantial decline in aerobic capacity occurs at age 60 and beyond. Highly trained runners, however, have a slower decline than untrained runners. Fauja Singh, for example, is credited as the oldest runner to complete a marathon at age 100.

Am I too young to run?

The American Academy of Pediatrics recommendations with respect to distance running that “if children enjoy the activity and are asymptomatic, there is no reason to preclude them from training for and participating in such events.” Children have a lower leg to trunk ratio until around age 12 and while growing are more susceptible to cartilage injury. Young children also are more vulnerable to heatstroke until sweating mechanics mature.

Is it safe to run during pregnancy?

The American College of Obstetricians and Gynecologists states, "Ideally, pregnant women should get at least 150 minutes of moderate-intensity aerobic activity every week. An aerobic activity is one in which you move large muscles of the body (like those in the legs and arms) in a rhythmic way. Moderate intensity means you are moving enough to raise your heart rate and start sweating." At risk or complicated pregnancies should consult with physician.

Is running recommended after orthopedic surgery?

While some studies have shown that running is not a risk factor for osteoarthritis and may actually be protective against OA, following orthopedic injury and surgery knee anatomy and running biomechanics are altered and therefore different factors are in play. Following ACL reconstruction, for example, there are quad muscle deficits noted at one year from surgery and beyond. There are well described progressive deterioration of articular cartilage and osteoarthritis findings in ACL reconstruction or partial menisectomy patients. The amount of injury resulting in the need for surgery is often connected to the prognosis for future progression of osteoarthritis.

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The orthopedic Tree of Andry is an image of a tree tied to a wooden stake for support. ArthroKinetix, as a modern, web3 based orthopedic newsletter, seeks to expand the Andry tree symbolism with the potential to showcase interactive healthcare data and its visualization. A work in progress... but for now enjoy our second iteration as a free mint. Socretea.