HOT WEATHER RUNNING UPPER
If you are a serious runner, or even if it is just a hobby, there is a good chance that the hot summer months don’t stop you from trying to get out and get running. Not only is track and field a spring competition sport, meet and public 5k, half marathons and marathons take place year round. Especially in certain parts of the world this can be some serious heat.
EFFECT OF HEAT ON PERFORMANCE AND SAFTEY
Data show us that the body’s response to rising temperatures is non-linear, meaning the performance will get exponentially worse moving from 70 to 90° F as compared to 50 and 70° F.
When running in thees temperatures, your organs and working muscles compete for a limited blood supply, which compromises the body’s natural cooling system. Humidity compounds the problem, by hindering the evaporation of sweat, making it harder to cool yourself. This leads athletes who are performing intense exercise in hot weather tend to become dehydrated. “With less water in the body, you have less blood plasma volume—the liquid portion of your blood—to serve all your needs.” (Hanc, J. (2019)
One writer for runners world pushed through a hot Dallas half marathon explaining that when weighing himself at the end of the race he had lost nearly four pounds. “That’s a 2.3 percent body-mass loss—anything more than two percent will affect your running,”.
While humidity compounds the issue by reducing sweats ability to evaporate, in a study of army training it was found that in dry heat, the peak oxygen consumption the soldiers were able to achieve was 5.7% lower than their maximal oxygen consumption in comfortable conditions.
FOOT RUNNING MOVEMENT
When designing an upper for running it is important to understand the movements in the joints for this particular motion. Running is going to have increased joint flexion in comparison to walking, but much linearity than a sport like soccer. (Dugan, S.A., & Bhat, K.P. (2005). Understanding the areas of the foot with the highest degrees of bending can help me simplify an upper to areas that need flexibility vs areas that can be stable on the foot.
This study called “Intrinsic foot motion measured in vivo during barefoot running” from the Journal of Biomechanics displays data on relative motion of individual foot segments. The 3-D measurements were taken in vive with the use of reflective marker arrays attached to pins inserted in the tibia, talus, calcaneus, cuboid and navicular. Data were collected using a 10-camera optoelectric system (Qualysis, Sweden).
(Arndt, A., 2006).
While that encompasses very specific bones in the foot and rotation from multiple planes, to break it down:
(Prior, T. (n.d.). Foot anatomy.)
The forefoot undergoes the most motion with the forward bend. But it is also important to consider the mid-foot, specifically the navicular and its slight rotation as the foot joint arch increases. The heel also undergoes rotation relative to the rest of the foot as a natural running motion takes place. (Windsor, 2014).
This movement is crucial to consider as it is found that restricting intrinsic motion of the foot could result in non-physiological stresses on specific foot bones or sites such as the ankle ligaments.
THE FOOT AND HEAT
When assessing the affect of heat on the body, I felt it important to look at the localized area on the body as well, the foot. The core temperature of the foot can play a role in the blood circulation and blood build if in the veins. Hot weather causes the blood vessels to dilate, so blood moves into the hands or legs by gravity. The extreme exercise coupled with heat vasodilation creates increases in capillary pressure. (Henry, J. P., & Gauer, O. H. (1950). All of these factors can contribute to a production of heat edema, a cutaneous condition characterized by vasodilatory blood pooling. The result is swollen feet and improper oxygen transport to the feet and toes. (Edema. 2017).
The best way to combat this is through hydration of the body and decreased localized core temperature of the foot which can helped through easier sweat evaporation from the upper.
When looking at preferred foot temperatures as a baseline it was found that while men and women have quite different lower and upper limits of foot temperature they they perceive as comfortable.
(Ciuha, U., & Mekjavic, I. (2017).
Over all average preferred temperature: TR: 18.7 ± 18.4 °C
Lower limit:
| Feet TR | Male 15.7 C | Female 19.4 C |
Upper limit:
| Feet TR | Male 26.2 C | Female 32.4 C |
While this is important to understand, the ability to perceive these temperatures can be inconsistent. In terms of perception, what I did find through my research though is the importance of perception of temperature and comfort. (Barkley, R, 2011).
WHAT MAKES A RUNNING SHOE COMFORTABLE
Perceived temperature of the foot plays a huge role in whether or not a shoe is successful. I felt that this is especially important to consider when a shoe would be worn in strenuous hot exercise. In a study done by Heel Luxe, this difference in perceived comfort and actual foot temperature increases were measured.
During my upper design I am going to take the shoe a direction that has keeping the foot cool at the core of its design. When addressing what can make a shoe cooler, materiality is key but I really want to take in to consideration how heat is best removed from the skin. This can be by processes of evaporation, convection, radiation and conduction. For these to happen, molecules in the air must bump against the hot (fast moving) molecules of the skin, so that some of that heat energy can be transferred from to the passing molecules. After they’ve made contact, the air molecules must move away, carrying what was our body heat with them in the form of quickly moving. (Wolchover, N. (2012). This is why a fan is so helpful, and why when sweating while running a breeze on the face feels so cool as it assists evaporative cooling. This same effect can be better produced on the foot if more of the skin is directly available to the air.
FIT & COMFORT
When moving forward with design I felt it important to first understand what makes a good fitting shoe, including areas that need to hug the foot vs areas that need room to breath. Heel Luxe offered a great guide to optimal shoe fit based on assessments of hundreds of shoes and perceived comfort.
I felt that this diagram was easy to understand, and counter intuitive to what I assumed about shoe fit. The areas I will focus on for fit of my upper is securing through the navicular, and tops of the toes but leaving room for movement on the lateral phalangeal joint and sides of the heel. (The Secret Ingredient for Step In Comfort at Retail. (2020).
CURRENT PRODUCTS/ INSPIRATION
After digesting all of this information, I am excited to move forward pushing how minimal I could make a running upper. When I think of hot weather and having more skin exposed to passing air, I think of sandals. The sandal market is rather saturated with a few companies really capitalizing on the active, moving, outdoor user. Teva is one company that has been known for their sandals versatile to the outdoors.
The goal of sandals with strapping configurations similar to this is to provide the best securement to the foot. Keeping the heel and shoe in contact is critical to avoid the toes curling and clenching the sandal that we see in flip flops. This extra, unnatural work would be critical to avoid in running.
This nylon linear straps around the foot that outdoor brands use lock around foot bones, however they create pressure points at where the bone sticks out the farthest as opposed to conforming with the bone. Areas where the foot has the highest flexibility wrapping around a strap can dig in at the peripherals of the strap. This is why for lower joint movements with less frequency like walking and hiking these solutions could work, but not for running.
Some other inspiration that related to the sneaker work is the sandal like aesthetics of these sportswear shoes nike has released. It is pushing the idea of a sneaker upper form, but lacking the functionality.
Nike Air Max FF 720
Nike Air Huarache Gladiator (Chochrek, 2018).
These styles are good inspiration for pushing for a minimal fabric upper but I feel can be pushed farther and taken into the performance world.
PATENTS
US20150000160A1
Description: A convertible article of footwear has an upper outer component with a reversible exterior shell, an inner sandal base and means for repeatedly connecting and disconnecting these two main components to one another with either outer shell exposed.
This was a very basic early concept of what a shoe combined with a sandal could look like. The functionality and aesthetic are questionable but I liked where there head was at!
US6606803B1
Description:
An X-strap assembly for securing an article of footwear to the instep of a foot, said footwear having a sole and channel through said sole, said X-strap assembly comprising: a strap attached at its respective ends to medial and lateral heel sides of said footwear, said strap having a first portion extending in a forward direction transversely across the instep from a first side of said footwear to a second side, a second portion extending through said channel, and a third portion extending in a rearward direction transversely across the instep from said first side to said second side of said footwear.
This is the kind of system that I see with a lot of the out door shoes with a variation of the strap going through a tunnel in the sole which I thought was interesting.
US5497564A
Description: A shoe construction employs straps formed of plastic material whereby separate areas of the shoe straps have different characteristics of elasticity, flexibility and rigidity. The construction of the strap provides areas connected to the shoe with greater elasticity and flexibility characteristics and a lesser rigidity characteristic than a second area of the strap that has greater rigidity characteristics and is connected to closure members of the shoe.
What I like about this concept is the variable flexibility of the straps which I feel works more naturally with how the foot moves over the course of the step.
US8146266B2
Description: The present invention employs chimneys and chimneys structures to move or vent heat and moisture away from the foot and out of the microclimate of the shoe. The chimneys define pathways that utilize convection and other principles to cool and dry the foot.
This concept by Timberland I felt was an innovative way to cool the foot while still having it covered and protected which is needed for their user. This way of cooling can be useful inspiration.
US20010025438A1
Description: The means for exposing front portion of foot is the open or exposed area of the means for covering top of shoe, which exposes some, a portion, or all of the toes, and may include an additional indentation to expose some or all of the pinkie toe as well.
What I liked when finding this design was that their problem realted to the problem I am solving and added to it. Their design expalined how during extended periods of walking and/or running blisters, chafing, athlete’s foot, and the loss of toe nails are common. This is because an individuals toes, and/or front portion areas of their foot are rubbing against the inside portion of the top or side areas of the upper.
PROJECT STATEMENT
Moving forward with this project I am to create an incredibly minimal upper for a running shoe. The straps that hold the foot in place to keep the heel locked down and foot in the shoe will have variable flexibility and conform to curvature of the foot bones for the most natural fit. The result will be a shoe that does not look like any other running shoe, pushes the boundaries and exposes skin to get the highest evaporative and conductive cooling possible.
CITATIONS
Chochrek, E. (2018, August 11). Nike Transformed Its Iconic Air Huarache Into a Gladiator Sandal. Retrieved from https://footwearnews.com/2017/focus/athletic-outdoor/nike-air-huarache-sandal-400130/
https://patents.google.com/patent/US20150000160?oq=sneaker+sandal
https://patents.google.com/patent/US6606803?oq=shoe+strapping
https://patents.google.com/patent/US5497564?oq=shoe+strapping
https://patents.google.com/patent/US8146266B2/en?q=keeping+foot+cool&oq=keeping+foot+cool
https://patents.google.com/patent/US20010025438A1/en?q=breathable+upper+running+shoe&oq=breathable+upper+running+shoe
Barkley, R., Bumgarner, M., Poss, E., & Senchina, D. (2011). Physiological Versus Perceived Foot Temperature, and Perceived Comfort, during Treadmill Running in Shoes and Socks of Various Constructions. Volume 10, Issue 3 American Journal of Undergraduate Research, 10(3). doi: 10.33697/ajur.2011.019
Henry, J. P., & Gauer, O. H. (1950). The Influence Of Temperature Upon Venous Pressure In The Foot. Journal of Clinical Investigation, 29(7), 855–861. doi: 10.1172/jci102318
Edema. (2017, October 26). Retrieved from https://www.mayoclinic.org/diseases-conditions/edema/symptoms-causes/syc-20366493#dialogId47296892
Ciuha, U., & Mekjavic, I. (2017). Thermal comfort zone of the hands, feet and head in males and females. Physiology & Behavior, 179, 427-433
Windsor, Williams, Songning Zhang, Dedrick, & Powell. (2014). High- compared to low-arched athletes exhibit longer foot-ankle moment arms during level running. 46(5), 809-809.
Hanc, J. (2019, June 11). The Heat is On. Retrieved from https://www.runnersworld.com/training/a20807061/the-heat-is-on/
Dugan, S.A., & Bhat, K.P. (2005). Biomechanics and analysis of running gait. Physical medicine and rehabilitation clinics of North America, 16 3, 603-21 .
The Secret Ingredient for Step In Comfort at Retail. (2020, March 25). Retrieved from https://www.heeluxe.com/the-secret-ingredient-for-step-in-comfort-at-retail/
Wolchover, N. (2012, July 9). Why Does a Breeze Feel Cool? Retrieved from https://www.livescience.com/34062-breeze-feel-cool.html
Arndt, A., Wolf, P., Nester, C., Liu, A., Jones, R., Howard, D., … Lundberg, A. (2006). Intrinsic foot motion measured in vivo during barefoot running. Journal of Biomechanics, 39. doi: 10.1016/s0021-9290(06)83644-4
Prior, T. (n.d.). Foot anatomy. Retrieved from https://www.timeoutdoors.com/expert-advice/running/footcare/foot-anatomy