Are you wondering how to choose the best running shoes for performance, comfort, and injury prevention?
In this blog, I discuss the research on running shoes and how to select the best pair for you!
Looking for rehab or performance programs? Check out our store here!
Anatomy of a Running Shoe
To start, it’s helpful to identify some of the key features of the running shoe that we’ll be talking about.
The insole is the innermost portion of the shoe under the removable sock liner.
The midsole is the foam between the insole and outsole and represents the bulk of the cushioning in a shoe.
The outsole is the harder/more durable outside of the midsole that interfaces with the ground.
This may include an integrated shank, or hard structure across the arch to increase the stiffness of the shoe.
These three sole features represent the stack height of the shoe, or total distance between outsole and insole.
Heel-toe drop is the differential between stack height at the heel versus the toe and commonly ranges between 12 and 0 mm.
The last describes the overall shape of the shoe’s sole, generally in straight, semi-curved, and curved categories.
The upper describes all material that encloses the foot around the sole.
The toe box forms the front end of the shoe from where the laces and tongue start.
The heel counter forms the back end of the shoe and is responsible for preventing forwards/backwards movement of the foot.
The toe spring is the curvature of the sole underneath the toe box and is commonly integrated into rocker-bottom type shoe designs. Rocker-bottom shoe designs refer to those that have a curved midsole to roll the individual forward onto their toes.
Running shoes have traditionally been thought to affect three major areas of running: injury management, injury prevention, and performance. Let’s dive into each, starting with management.
Can Certain Shoes Be Used To Manage Specific Injuries?
It should be noted that running shoe prescription should almost never be the primary treatment for a running injury. A comprehensive approach to running injury management involves the assessment of training load (volume, intensity, and frequency of running), tissue-related factors such as mobility and strength, and recovery factors like nutrition and sleep.
That said, knowledge of running shoe biomechanics can be helpful for the management of some running-related injuries.
A 2015 expert consensus defined minimalist running shoes as “footwear providing minimal interference with the natural movement of the foot due to its high flexibility, low heel to toe drop, weight and stack height, and the absence of motion control and stability devices” (Esculier 2015). These five categories, which are often seen in conjunction with each other, play a role in where stress is shifted during running.
The more minimalist a shoe is, the more the foot and ankle will be loaded during running. Conversely, more maximalist shoes may shift this load more proximally to the knee and above.
It is often difficult to determine how much of this comes from the properties of the shoe itself versus the altered gait pattern that happens with a change in shoes (such as a change in running cadence or foot strike pattern). That said, clinicians may choose to prescribe a temporary change in running shoes while managing an injury. This contributes to the goal of reducing load on the specific structure while maximizing the amount that the runner can continue to train comfortably.
For example, someone dealing with an Achilles tendinopathy would likely do well in the early stages of running with a shoe that decreases plantar flexor loading, like a neutral shoe with a higher heel-toe drop and low flexibility.
Conversely, a runner experiencing patellofemoral pain may do well in a lighter shoe which promotes a higher running cadence and subsequently shorter step length, reducing load on the patellofemoral joint.
Keep in mind that you’d likely want to avoid quick, extreme changes in any direction to minimize the risk of injury elsewhere.
Can Running Shoes Cause Injuries?
When discussing running shoes and injuries, it’s important to address one of the most common questions that healthcare professionals receive in this area: “Can running shoes cause injuries?”
Injury causation is complex and involves more than one contributing factor at any given time. Despite recreational runners commonly believing that wearing the wrong shoes can cause running injuries (Saragiotto 2014), a systematic review by van Poppel et al. in 2021 found no relationship between running shoes and the development of running injuries. It should be noted that research often studies all running injuries grouped together, so it is unknown if certain types of running shoes are associated with specific running injuries.
Rather than thinking of running shoes as causative factors for injury, Malisoux et al. proposed an effect modifier relationship.
An effect modifier is a variable that can increase or decrease the strength of an existing relationship. In this case, it has been suggested that while the runner’s training load is the largest contributor to causing a running injury, running shoes can increase or decrease the amount of training needed to sustain said injury.
For example, as mentioned earlier, minimalist shoes result in higher loads at the foot and ankle (Conners 2023). If a runner’s training includes qualities that also load the foot and ankle more, such as running uphill or performing speedwork, the presence of minimalist shoes may contribute to the overload of a structure in that location.
Can Running Shoes Prevent Injuries?
Based on the effect-modifier model, running shoes are able to shift stress towards or away from certain structures in the body, but have not been shown to prevent injuries. Historically, the “anti-pronation” model of running shoes was developed on the foundation that excessive rearfoot pronation (a combination of ankle eversion, forefoot abduction, and dorsiflexion) during running was causally linked to injuries (Agresta 2022). Traditionally, this was measured in a static or standing position and if a runner had a lower arch height, they were labeled as excessively pronated.
As a result, shoe construction to prevent various degrees of pronation was emphasized. What we now know is that there are several fundamental flaws in this model based on updated research. Consider these three questions:
1. Are we actually measuring pronation?
Arch height measured statically does not predict the movement of the foot during dynamic activities like running. Dicharry et al. in 2009 found that factors other than static arch height, such as neuromuscular control and external forces, had a large effect on dynamic foot mobility during running in healthy recreational runners.
2. Is pronation a risk factor for running injuries?
Rearfoot pronation has not been shown to be a risk factor for the development of running injuries. In a one-year prospective study on 927 novice runners, runners statically categorized as pronated or supinated did not show an elevated risk of injury compared to neutral arch height (Nielsen 2013). In fact, the pronated group actually had fewer injuries in this study compared to the neutral group, albeit a small relationship.
3. Do running shoes constructed to reduce pronation decrease running injuries?
Prescribing running shoes based on static arch height has not been shown to affect injury risk as compared to prescribing them randomly. For example, a 2014 study on over 7000 military recruits demonstrated no difference in injury risk between these two conditions (Knapik 2014).
As such, the idea that elements in the shoe to control the movement of the arch need to be customized to the foot for injury prevention has fallen out of favor.
Can Certain Shoes Improve Performance?
A popular topic of discussion with the improvements in running shoe technology is on running performance. There are three primary determinants of running performance: Vo2max, lactate threshold, and running economy. Of these, only running economy appears to be affected by changes in shoes.
Running economy is the measure of efficiency, or metabolic energy cost, to run at a certain pace. When you improve your running economy, you decrease the amount of energy expenditure used to run at a given pace.
Changes in running shoes have been reported to improve running economy and time trial performance by as much as 6%, with a 2015 study noting four major shoe features contributing to this: shoe weight, midsole material, midsole thickness, and longitudinal stiffness (Nigg 2015).
The effects of running shoe weight on running economy have been reported since the 1980s, with multiple studies confirming that decreasing shoe weight by 100 grams improves running economy by around 1% (Hoogkamer 2016).
It should be noted that this percent improvement in running economy is not the exact improvement in running performance; at paces faster than 3 meters per second, the percent improvement in running speed is around two-thirds of the improvement in running economy (Kipp 2019).
Resilience, or the amount of energy returned after deformation, is an important concept in running shoe construction. The material used in the midsole may have different resiliency properties, with Hoogkamer et al. describing a range of 65% in traditional shoes to 87% in new high performance shoes (nicknamed “super shoes”). An increase in midsole thickness not only allows a shoe to contain a greater amount of energy resilient foam, but also supports the addition of several other features that are thought to contribute to an increase in running economy like carbon fiber plates or rocker-bottom design (Burns 2019).
The longitudinal bending stiffness of the shoe has shown mixed results in changing running economy, with increased stiffness resulting in less energy lost at the first MTP joint and conflicting effects at the ankle (Ortega 2021). The shape and placement of the plate may have the most significant impact on ankle mechanics and the range of running economy changes, both positive and negative.
To summarize this section, light shoes with a high density of resilient material and a stiff, curved shape have been shown to improve running performance at the group level. On the individual level, there may be some runners that benefit more than others from these shoe features.
Selecting A Running Shoe
So how should you select your running shoe?
In the absence of strong evidence to guide us on injury prevention, we circle back to two questions when giving runners advice:
- How comfortable are they?
- How similar are they to the shoes that you’re already used to?
While the comfort filter paradigm hasn’t demonstrated that it’s better at reducing injuries than any other theory, it seems sensible for comfort to be an important factor in the decision-making process (Nigg 2015). While this would be a subjective experience for each individual, cushioning and the overall fit of the shoe are likely important here.
Practically, we recommend trying on several different models of shoes and selecting the most comfortable upon wear-testing.
Using similar biomechanical principles to those already discussed, the time needed to adjust to a new pair of running shoes may depend on what the body is currently adapted to.
Warne et al. in 2017 reviewed the evidence on transitioning to minimalist shoes and gave recommendations that include initially decreasing running volume and gradually phasing in the new shoes. While there has been much focus on being conservative when transitioning to shoes with less support to give time for the foot and ankle to adapt, it makes sense to adopt this approach when transitioning to or from any extremes in cushioning level, heel-toe drop, or flexibility.
Practically this might look like starting with one short, easy run in the first week with the new shoes while keeping everything else the same and then gradually increasing both the run frequency and single run duration in the new shoes before increasing intensity.
If the goal is running performance, lighter shoes are generally preferred, as previously noted. Most brands have their version of the light “super shoe” at this time, so trying a variety of different options and picking the most comfortable would be a good place to start. Consistent with our other recommendations, care should be taken to gradually onboard these shoes into a rotation before racing in them.
How Often Should You Change Running Shoes?
This is a common question from runners and it depends on several factors, including training characteristics and shoe construction.
Cook et al. lab tested 25 different models of running shoes and saw a 25% reduction in foam shock absorption within 50 miles. This increased to over a 40% reduction by 300 miles. Additional lab studies have shown up to a twofold increase in plantar pressure after 300 miles and structural damage in foam after 400 miles (Verdejo 2004).
Because of the variability in running mileage from one runner to the next, it likely makes more sense to change running shoes based on mileage rather than time. Shoes with more cushioning may be able to last into the 300 mile range, but lower cushioned shoes may need to be phased out before 200 miles.
Summary
There is still quite a bit of confusion in popular media about the role of running shoes as it pertains to injury and performance.
Currently, we don’t believe that running shoes play a major role in the development of injury, nor are they very impactful in treatment. On the performance side, some newer types of shoes have been shown to be effective in improving running efficiency and speed.
How should you select one?
Try a lot of different shoes and pick the most comfortable model – ideally something similar to what you previously were accustomed to, but if not, take your time to work them into your routine.
Looking for rehab or performance programs? Check out our store here!
Want to learn more? Check out some of our other similar blogs:
Strength Training For Runners, Achilles Tendinopathy, Plantar Fasciitis Rehab
Thanks for reading. Check out the video and references below.
References
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- van Poppel D, van der Worp M, Slabbekoorn A, et al. Risk factors for overuse injuries in short- and long-distance running: A systematic review. J Sport Health Sci. 2021;10(1):14-28.
- Malisoux L, Theisen D. Can the “appropriate” footwear prevent injury in leisure-time running? Evidence versus beliefs. J Athl Train. 2020;55(12):1215-1223.
- Connors G, Mathew J, Freeland E. Biomechanics and injury prevention for barefoot/minimalist running. JBJS Rev. 2023;11(11).
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- Nielsen RO, Buist I, Parner ET, et al. Foot pronation is not associated with increased injury risk in novice runners wearing a neutral shoe: a 1-year prospective cohort study. Br J Sports Med. 2014;48(6):440-447.
- Knapik JJ, Trone DW, Tchandja J, Jones BH. Injury-reduction effectiveness of prescribing running shoes on the basis of foot arch height: summary of military investigations. J Orthop Sports Phys Ther. 2014;44(10):805-812
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