The Rundown on Running Shoes!

9 Mins

The Rundown on Running Shoes!

Including considerations for pregnant and postpartum runners.


In this blog we’ll talk about a few basic characteristics of running shoes, 2 key rules to follow when picking out a shoe, and special considerations for pregnant and postpartum runners!

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The Anatomy of a Running Shoe 


The diagram below gives an overview of a few main characteristics of a running shoe. Choosing a shoe with specific characteristics could benefit running performance and health!


 


Cushion:

Running shoe cushion ranges from a near barefoot experience to the currently trending high cushion maximalist shoe. Contrary to popular belief, while maximalist shoes may increase perception of comfort and decrease foot pressure (Ogston 2019), they may actually increase the vertical forces experienced by the leg joints during running (Pollard 2018, Kulmala 2018)! Consequently, maximalist shoes may be a good choice for those wanting a softer ride or who have foot problems, but they are probably not making running any easier on the rest of the body. 

On a different note, shoe cushioning is important to consider when you want to run fast! Performance racing shoes such as the Nike Vaporfly Next % and Saucony Endorphin Pro are effective largely due to the energy return properties of the unique foam cushioning (Healey and Hoogkamer 2021). These specific types of cushioning may actually improve running performance.


Bending Stiffness:

Bending stiffness refers to how stiff a shoe feels when bent longitudinally (front to back). This characteristic can be modulated through a plate (carbon fiber, plastic etc.) included in the shoe sole (see diagram).

Current research tells us that individuals respond to shoe bending stiffness in very different ways! Some people perform best in a flexible shoe, and some in a fairly stiff shoe (McLeod 2020), so it’s important to pay attention to how a shoe feels for you personally when you run/race.


Toe spring: 

The toe spring of a shoe refers to the upward turn of the sole that extends from the base to the tip of the toe. Shoes with a large toe spring curve give you a ‘spring forward’ sensation  when you push off the ground. Hoka One One is a brand known for producing large toe spring shoes.

Shoes with a large toe spring will likely require less work from the ankle (Sobhani 2017, Boyer 2009), but may increase the load on the knee (Sobhani 2017). Consequently, they are an awesome option for people with ankle problems, or achilles tendonitis (I can personally attest to this!), but may not be a great choice for someone with knee problems. 

If you are interested in learning more about this topic, this is a great resource: Toe Spring in Running Shoes - How It Can Help or Hurt Your Running 


Heel to toe drop:

Heel drop refers to the difference in shoe height from the heel to toe base, and will influence running footstrike. A higher heel drop encourages a heel strike, which will distribute higher loads on the knee/hip (and lower comparative loads on the ankle/foot). Shoes with a lower heel to toe drop encourage a midfoot or forefoot foot strike and distribute higher loads on the ankle/foot (and lower comparative loads to the knee/hip). A traditional running shoe will have a heel drop of about 10mm. Though there is no optimal heel to toe drop, changing this characteristic could be beneficial if you are having specific types of problems. For example, in the past I have switched to high drop shoes in order to treat Achilles Tendonitis (in an effort to decrease the load on my ankle).  Changes between high and low drop shoes needs to be done gradually due to differences in muscle activation, a quick change could result in muscle soreness and possible injury. 


Midfoot Construction:

Shoes with a dense inner midfoot are sometimes recommended for runners who need arch support, have excess foot pronation, or who experience shin splints. These shoes are called stability or motion control shoes. More information on these shoes can be found here: Running Shoes. What difference does it make? 

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2 Key Rules to Follow When Picking Out a Running Shoe



1. “The Comfort Filter”:

This comes from some amazing work done by Dr. Benno Nigg in Calgary, Canada (Nigg 2015). His lab found that every person follows an individualized ‘preferred movement path’ while running.This path uses the least energy and is related to positive outcomes in injury, fatigue etc. The shoes that feel comfortable to a runner are also the shoes that help their body continue to follow this preferred movement path. This is called the ‘comfort filter’. We can infer that when a runner chooses a shoe based on comfort, they may use less energy to run and have decreased injury risk while wearing that shoe. 

What does this tell us? Our bodies are amazing and know best! Even if all your friends and all the pros swear by a certain running shoe, if it doesn’t feel comfortable on your feet- don’t wear it!


2. Shoe Variety is Essential!

I have been guilty in the past of finding a running shoe I love (hello Saucony Kinvaras) and then proceed to wear that shoe everyday- for every workout and race- for the next….. 5+ years. I know better now!

Every aspect of a shoe (weight, heel drop, cushioning, upper construction etc.) will cause wear on your body in a unique way (muscle activation patterns, wear on ligaments/joints/skin etc.). If you wear the same pair of shoes all the time, this repeated high ‘wear’ can easily lead to injury. If instead you cycle between shoes with a variety of characteristics, you will have low ‘wear’  in many different spots throughout your body. This will significantly decrease your chances of injury and allow your body better recovery! Buying multiple shoes is definitely an investment at first, but will pay off in the long run (pun intended)!



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Should I Change My Running Shoes When Pregnant or Postpartum?


The answer is (of course) that it depends! There is so much individual variation in bodily pregnancy changes and postpartum recovery. Listed below are a few general recommendations for pregnant and postpartum running footwear- Keep in mind that all the suggestions may not apply to you, but could be helpful to look into if you experience problems while running!


➤Increase Cushioning:

Increased body weight and plantar pressure is common during pregnancy (Karadag-Saygi 2010). Consequently, choosing a shoe with higher cushioning may be a good option to increase comfort and allow a softer ride under the foot.


➤Decrease Heel to Toe Drop:

Pregnant women often experience a forward shift of their foot center of pressure while walking/running due to a growing baby bump (Forczek 2018). This will often change their footstrike, causing the foot to land on the mid to forefoot instead of the heel (Forczek 2018). Due to this change in footstrike, pregnant runners may be more comfortable with a shoe constructed with a lower heel to toe drop (see explanation above concerning the association between footstrike and heel drop).  


➤Increase Shoe Size and Width:

Due to swelling and a collapse of the foot arch (explanation below), pregnant women often experience an increase in both foot width (Ramachandra 2017) and length (Segal 2013). This change in foot size can happen as early as 24 weeks pregnant, and will likely go away during the postpartum period (Ramachandra 2017). It may be helpful to purchase a larger shoe, or loosen the shoe lacing to keep your foot from rubbing!


➤Consider Your Arches:

Research has found that pregnant women experience a drop in arch height and rigidity, likely due to an increase in body weight and the hormone relaxin (which will increase joint laxity) (Segal 2013). This change in the arches is thought to be permanent, lasting beyond the postpartum stage (Segal 2013).

Should we be worried about a drop in arch height? Arch drop will lead to increased foot pronation and flatter feet, but neither of these conditions are necessarily bad! Despite popular belief, neither condition has proven association with injury, and not everyone will need corrective shoes or orthotics (Khan 2021, Nigg 2015).

However, speaking biomechanically- a flatter and more pronated foot will cause increased internal rotation of the leg, as well as alter the natural control of forces going through the foot (Segal 2013). This may increase risk of injury at the knee and hip, and could even affect pelvic alignment and the spine (Segal 2013, Ramachandra 2017).

If you find yourself with these types of problems or even just general foot or heel pain, it would be beneficial to talk to a podiatrist. It is possible that using an orthotic (Karadag 2010), or using a stability or motion control running shoe could help to redistribute pressure in your foot and help with these types of injuries! This may be especially important in the postpartum period as you get into more intense running.

This is a fantastic resource for all things related to shoes, foot arches and arch support: The Truth About Arch Support - A Meta Analysis of 150 Studies 




References:


Boyer, Katherine A, and Thomas P Andriacchi. “Changes in running kinematics and kinetics in response to a rockered shoe intervention.” Clinical biomechanics (Bristol, Avon) vol. 24,10 (2009): 872-6. https://doi.org/10.1016/j.clinbiomech.2009.08.003

Forczek, Wanda, Yury P. Ivanenko, Joanna Bielatowicz, and Karolina Wacławik. “Gait Assessment of the Expectant Mothers – Systematic Review.” Gait & Posture 62 (May 2018): 7–19. https://doi.org/10.1016/j.gaitpost.2018.02.024.

Healey, L., & Hoogkamer, W. (2021). Longitudinal bending stiffness does not affect running economy in the Nike Vaporfly. SportRiv. https://doi.org/10.31236/osf.io/37uzr

Karadag-Saygi, Evrim, Feyza Unlu-Ozkan, and Alin Basgul. “Plantar Pressure and Foot Pain in Last Trimester of Pregnancy.” Foot and Ankle International 31, no. 2 (February 2010): 153–57. https://doi.org/10.3113/FAI.2010.0153.

Khan, Sadi. “The Truth About Arch Support- A Meta Analysis of 150 Studies.” Run Repeat, 17 March 2021, https://runrepeat.com/arch-support-study.

Kulmala, Juha-Pekka, Jukka Kosonen, Jussi Nurminen, and Janne Avela. “Running in Highly Cushioned Shoes Increases Leg Stiffness and Amplifies Impact Loading.” Scientific Reports 8, no. 1 (December 2018): 17496. https://doi.org/10.1038/s41598-018-35980-6.

McLeod, Aubree R., Dustin Bruening, A. Wayne Johnson, Jared Ward & Iain Hunter (2020): Improving running economy through altered shoe bending stiffness across speeds, Footwear Science, https://doi.org/10.1080/19424280.2020.1734870

Nigg, Bm, J Baltich, S Hoerzer, and H Enders. “Running Shoes and Running Injuries: Mythbusting and a Proposal for Two New Paradigms: ‘Preferred Movement Path’ and ‘Comfort Filter.’” British Journal of Sports Medicine 49, no. 20 (October 2015): 1290–94. https://doi.org/10.1136/bjsports-2015-095054.

Ogston, Jena Kay. “Comparison of In-Shoe Plantar Loading Forces between Minimalist and Maximalist Cushion Running Shoes.” Footwear Science 11, no. 1 (January 2, 2019): 55–61. https://doi.org/10.1080/19424280.2018.1561760.

Pollard, Christine D., Justin A. Ter Har, J.J. Hannigan, and Marc F. Norcross. “Influence of Maximal Running Shoes on Biomechanics Before and After a 5K Run.” Orthopaedic Journal of Sports Medicine 6, no. 6 (June 1, 2018): 232596711877572. https://doi.org/10.1177/2325967118775720.

Ramachandra, Preetha, Pratap Kumar, Asha Kamath, and Arun G. Maiya. “Do Structural Changes of the Foot Influence Plantar Pressure Patterns During Various Stages of Pregnancy and Postpartum?” Foot & Ankle Specialist 10, no. 6 (December 2017): 513–19. https://doi.org/10.1177/1938640016685150.

Segal, Neil A., Elizabeth R. Boyer, Patricia Teran-Yengle, Natalie A. Glass, Howard J. Hillstrom, and H. John Yack. “Pregnancy Leads to Lasting Changes in Foot Structure.” American Journal of Physical Medicine & Rehabilitation92, no. 3 (March 2013): 232–40. https://doi.org/10.1097/PHM.0b013e31827443a9.

Sobhani, Sobhan et al. “Biomechanics of running with rocker shoes.” Journal of science and medicine in sport vol. 20,1 (2017): 38-44. https://doi.org/10.1016/j.jsams.2016.04.008

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