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It is one of the most common criticisms of the American healthcare system: much of the care provided is focused on being retroactive, addressing the problem after years of festering and development instead of a proactive approach with early intervention and education on prevention. The reasons for this structure are multifactorial and difficult to rectify, but the reactionary pattern does not have to be adopted by runners, especially those new to lacing up.
Running-related injuries have long been a part of the sport, as demonstrated by numerous meta analyses. It has been reported in the literature that 50 percent of runners sustain an injury per year and 25 percent of all runners are injured at any one time, per the American College of Sports Medicine. The bulk of running-related injuries are classified as overuse injuries, with the majority presenting in the knee, foot, and lower leg. Specifically, patellofemoral syndrome (“runner’s knee”), iliotibial (IT) band syndrome, medial tibial stress syndrome (shin splints), Achilles tendinopathy, and plantar fasciitis are the most commonly cited, in addition to various types of stress fractures and muscle strains.
But what if the very risk factors associated with these injuries could provide runners with opportunities to potentially prevent them from occurring in the first place?
The answer is yes, and ranges from identifying common gait patterns to shoe choices, to keeping a close eye on training patterns and modifications. Let’s take a look at what the most current scientific literature has to say about some of these predictors!
Biomechanics and Form
A 2018 study by the American Journal of Sports Medicine aimed to determine if there was a common pathological gait that was associated with the four most frequent running-related injuries (runner’s knee, IT band syndrome, shin splints, and Achilles tendinopathies). Examining 72 injured runners and 36 healthy runners, researchers found that the key predictor and common link among the injured runners was hip drop, also known as “contralateral pelvic drop,” wherein the limb, or hip, that is not on the ground while running sinks down below the level of the stance hip. Strikingly, for every one degree of contralateral pelvic drop, this resulted in a whopping 80 percent increase in injury risk. The study also noted forward trunk lean (versus a forward lean at the ankles) at midstance and a more extended knee and dorsiflexed ankle at heel strike as being commonalities amongst the injured group, but with less correlation than contralateral pelvic drop.
There are hundreds of shoes to choose from, so how can you be sure you have a pair that matches your gait? With the boom in maximally cushioned shoes and supershoes (shoes with a combination of bouncy foam in the midsole and one or more carbon plates), are there ways to utilize these trends while preventing injury?
It has long been suggested that heavier runners should be in higher cushioned shoes, in order to provide more shock absorption to prevent injury. A study from 2020 gave 848 healthy runners one of two different types of shoes, only differing in their global stiffness. The runners were classified as light or heavy, based on the median body mass for men (78.2 kg) and 62.8 kg for women. (Note that these numbers and classifications are based on this specific population sample and the authors’ verbiage; height and muscle mass were not measured and body mass does not define fitness or worth.). Across the board, all runners who received the hard shoes had a higher injury risk, compared to those who received the soft shoes, but those with higher body mass were not associated with greater risk for injury. The protective effect of the higher cushioned shoes was only found to be significant in the lighter runners.
A key benefit of carbon-plated shoes is the shoes’ ability to store (and return) more energy in the midsole, taking the strain off of the muscles and tendons of the foot and ankle, and effectively improving running economy. However, the change in biomechanics could be a precursor for injury for some. A study from 2023 presented cases of navicular stress fractures in athletes utilizing carbon plated shoes, citing novel demands on the foot–namely increased plantar displacement of the navicular bone, modified forces to the hindfoot, as well as training at faster velocities.
What about the heel-to-toe drop, referring to the difference in stack height between the heel of the shoe and the forefoot? A study from 2022 demonstrated that the peak patellofemoral joint stress was increased by over 15 percent while running in shoes with 10-15 mm drops (also known as a more “traditional” running shoes), significantly contributing to the mechanism of runner’s knee pain. The study found that shoes with a heel-to-toe drop of 5 mm had much lower stress on the joint.
It’s generally believed that shoes don’t cause injuries. A study from 2020 outlines that radical changes in shoe gear are what inevitably increases injury risk, but overall, the generalizations made about specific footwear characteristics are oversimplified and not sufficiently backed by scientific evidence. The authors underscore that each runner is unique and will adapt in their own way to a particular shoe type. Like most things in life, caution and common sense should be exercised.
Training Load and Patterns
Training load and patterns are among the most studied predictors of injury in runners, with the most straightforward and consistent results. A study by the British Journal of Sports Medicine, published in 2022, took a look at 735 runners via their Strava accounts, who were training for the New York City Marathon. They were monitored for 16 weeks, with their training divided into quarters. They found the injury incidence to be 40 percent among the athletes, with those sustaining injuries during the third quarter to have run less overall mileage during the second quarter compared to healthy runners. They also found that athletes who sustained an injury during the first quarter of training had increased their training volume by over one and a half times within seven days compared to the last 28 days of training.
Many athletes look to weekly mileage as the standard way to quantify their training load. A study by the Journal of Orthopaedic and Sports Physical Therapy published in 2020 outlines how running distance should not be the sole training metric, as it can often misrepresent and significantly underestimate training stress and resulting adaptation, leading to injury. The researchers push for a shift from the obsession over weekly mileage to quantifying training loads by minutes run per session multiplied by rate of perceived exertion for the session. For elite and professional level athletes, they encourage measuring biomechanical external load metrics (this requires special equipment) coupled with internal load metrics: physiological (i.e. measuring blood lactate levels) and psychological (rate of perceived exertion) for more accurate injury prediction.
So how can we apply all of this in real life?
A Coach’s Perspective:
- It’s Complicated. There are many factors that lead to running-related injuries. Some are easier to study in a research setting than others! Having a prior running-related injury is often predictive of future injuries, but the pattern can be stopped with a handful of interventions.
- Knowledge is Power. Eating and sleeping enough to sustain training is the base of the pyramid and the lowest-hanging fruit. RED-S (relative energy deficiency in sport), history of disordered eating, and lack of quality sleep (which often presents in tandem with the aforementioned patterns) all contribute significantly to the risk of stress fractures and muscle strains. Sometimes slipping into an energy deficit occurs without a history of disordered eating. Knowledge of caloric and nutrient needs while training is power. Working with a trusted registered sports dietitian in addition to a mental health specialist can be paramount in preventing running-related injuries.
- Consider a Gait Test. Whether you are a new or seasoned athlete, there is enormous benefit in having your gait analyzed by a professional, whether that’s with a physical therapist, a sports medicine doctor, or an exercise physiologist who specializes in biomechanics. Doing so can identify imbalances that can be improved via strength and neural relearning. While it may seem frivolous to have this done in the absence of an injury, a gait analysis is an investment in yourself and is taking the preventative approach at its finest.
- Build Strength. Work with your physical therapist and certified strength and conditioning specialist to build strength in weak or previously dormant areas. Focusing on glute and hip strength can often prevent injuries from happening further down the kinetic chain.
- One Size Doesn’t Fit All. Shoe selection is highly specific to each athlete. Shoe design trends and materials change frequently, and not everyone is suited for each. Run away if you encounter someone who is all-in on a trend, applies it to every runner, and doesn’t respond to the question of which shoe is the best with “it depends.”
- Drop too Much Drop. For athletes with a history of knee pain, going into a shoe with around a 5 mm heel to toe drop, compared to shoes in the 10-15 mm heel to toe drop range, helps relieve stress on the knee joint.
- Cushion Can Help. Cushioning is important and, when compared to harder soled shoes, carry less of an injury risk. If you are a taller athlete who weighs more than your shorter comrades, this doesn’t mean you have to go into a maximal cushioned shoe. Choose the shoe you feel comfortable in and that is recommended to you by a professional.
- Be Selective About Carbon. Nearly every major shoe brand has at least one carbon-plated shoe these days. They are all very different, with some having softer midsole foams than others, some having stiffer plates than others, and a variation where the plate sits in relation to the foot. If you are new to carbon-plated shoes, save these shoes for key workouts and races, in order to lessen injury risk. Remain cognizant of any pain or glaring biomechanical differences that occur, as you may need to spend time in a non-plated or a different carbon-plated shoe. If you are utilizing a carbon-plated trail shoe, be sure to test them out on the specific terrain you’ll be racing on to be sure the responsiveness is in alignment with your gait, goals, and level of technicality. Also, many carbon-plated trail shoes can be less predictable on technical terrain, often resulting in greater lateral instability. On the contrary, utilization of carbon-plated shoes in higher level athletes can help with recovery following hard sessions.
- Minutes Over Miles. Build a gradual, aerobic base before entering into a focused training block. Many coaches and physical therapists warn age-group athletes about running too much or too fast, too soon. Avoid large leaps in mileage or rapid additions of novel stimuli like speedwork or hills. Consider pivoting your runs to being time-based, journaling your rate of perceived exertion (using a scale from 1-10), taking floating rest days based on how you are feeling, and letting go of a fixation on weekly mileage. Work with a trusted running coach to build a logical, stepwise plan to achieve your goals.
Predicting injury risk is multi-faceted and not always straightforward, but we have a lot of data out there to guide us in the best ways to prevent running-related injuries before they occur. Much of the preventative measures require investing in yourself upfront, but it could potentially save you a lot of time, money, and stress by doing so. Taking the preventative approach can at times feel laborious, but it’s worth it in the long run.