Problem: My cushioning system will utilize air pressure to reduce impact force, preventing lower extremity injuries. This allows for increased athlete training hours, and enhanced performance. There are a wide range of running shoes on the market that utilize differing midsole technology when it comes to impact protection. The impact force of the athletes’ foot hitting the ground can be detrimental if left unprotected. The amount of repetitive loads, and the frequency of loading all contribute to the bone failing (Frey MD, 1997). Every athlete is different, and variability can range in foot strike, impact force, ground being run on, and recovery routines.
Design: I propose a cushioning system that will be customizable depending on the users cushioning preference. The midsole of the shoe will be comprised of two large air bladders, connected in the middle, with air sealed inside at optimal pressure. Optimal Pressure will be observed based on level of impact absorption/firmness of midsole that the athlete prefers. The Adjustable Air Unit will act as a stand alone outsole similar to current Nike VaporMax Air technology. The adjustability is applied with changing the amount of air pressure in the midsole. This can be change by interacting with the small valve located on the heel of the shoe. I am unsure of the integration of a hand held tool. The tool would include a gauge with guided air pressures for standard impact settings, and a pump mechanism to release/increase air pressure.
Inspiration: When looking at how to best portray my idea based on forms in the market right now sleeping pads came to me as a conceptual representation of my cushioning system. The ability to control air input and output while using durable and elastic materials. I definitely think you could explore forms and shape of the air unit itself as well as how the air will transfer and disperse throughout the midsole. I like the idea of the baffles and textures that the sleeping pads show. It makes the inflated material more elegant and purposeful.
Background: Athletes feel differing amounts of impact control from shoes because of the way they run isn’t standardized. It is important that they are able to control the cushioning in their midsole as opposed being limited to the levels on the market. This extra amount of customization can help prevent running injuries in the future. The cushioning might also want to be changed depending on the environment. An athlete can provide more impact resistance when running on the street vs. on a trail to prevent running injuries. There is an ongoing controversy over the amount of cushioning running shoes should utilize. Some people argue it is little to none, but some prefer running on large cushy midsoles. When investigating this problem myself, as a runner, I have gone back and forth. After reading “Born to Run,” a novel by Christopher McDougall, I was convinced that I needed to ween off cushioning and slowly went from Asics Gel Cushioning to Nike Free Runs. But one thing that I felt that I miscalculated along that transition was the environment that I was in. According to ‘Risk of Injury in Trail Running,’ 10 trained trail runners were compared to 9 trained road runners during barefoot and shod (in shoe) running trials. Road runners exhibited greater mean peak knee flexion and foot strike angle. Overall the study suggested that road runners were at greater risk of running related injuries in comparison to trail runners. “Forces that are repeatedly applied to the body could lead to positive remodeling of a structure if the forces fall below the tensile limit of the structure and if sufficient time is provided between force applications (Hreljac 2004).” My cushioning system will provide a custom barrier between the athlete and striking surface that will protect against ground impact forces and decrease the amount of time needed between repetitive force applications. Recent research shows that runners who have large and rapid impact forces while running are at an increased risk of developing an overuse injury of the lower extremity (Hreljac, 2004). Runners injuries range from plantar fasciitis, Achilles tendinopathy, runner’s knee, and shin splints, all painful and require rehabilitation.
Existing Solution/Patents: When looking into air cushioning systems that exist today, Nike Inc. is definitely one of the most iconic users of air on the market. NikeAir uses pressurized air in a durable, flexible membrane to provide lightweight cushioning. The air compresses upon impact and then returns to its original shape. One of the first patents that I looked at, US8037623B2, explained athletic footwear having an air filled bladder disposed in a sole structure. It also explains how in operation, the bladder may absorb shock when the footwear contacts a playing surface (Passke, 2011).
Another Nike Inc. patent that I investigated was for a shoe having an adjustable cushioning system. The cushioning piece is 4 fluid-filled support chambers which are compressible but not collapsible and are in different location throughout the midsole of the shoe. By selectively isolating one or more of the reservoir cambers from one or more of the support chambers, and collapsing the isolated chamber, fluid may be moved from one support chamber to another at a different location, increasing the stiffness of the midsole at the selected location (Potter, 1995). I thought that this patent was relevant to me because it shows one way of adjusting stiffness within the shoe itself without adding air or fluid to the midsole. The way I am approaching the changes in stiffness is by adding air or letting air escape as opposed to transferring it.
I also found lots of patents that were relevant to air cushioning systems from Reebok. One of them was for a shoe having an inflatable bladder. The bladders would be comprised of sheets of polyurethane or polyester film attached together to form an airtight seal. The shoe would also have an inflation mechanism for selectively introducing air in the one or more bladders. I also thought this patent was interesting because it noted an inflated lacing system (Marvin, 2012). 
Another patent that Reebok has, EP0876113B1, is for support and cushioning system for an article of footwear, which includes having a bladder disposed above the sole and beneath the wearer’s foot to provide added cushioning. The bladder has air at above ambient pressure that is formed by thermoforming/welding sheets of durable, flexible material together. The heal chamber and forefoot chamber are connected allowing dispersion of airflow (Jessiman, 2003).
Finally, I looked at a patent for Air Cushion Shoe Sole invented by Ing-Chung Huang that describes an air cushion shoe sole which is preferably blow molded of elastomeric material and has at least one cavity which in cross section is substantially rectilinear. The cavity has a lot of depressions and each cavity has an air valve for putting shock absorbing materials in. Materials including either gas, liquid, or a combination (Huang, 1988).
Papers:
Cole , GK, et al. “Lower Extremity Joint Loading During Impact in Running .” Clinical Biomechanics , vol. 11, no. 4, June 1996, pp. 181–193., www.sciencedirect.com/science/article/abs/pii/0268003396000083. Frey , Carol.
“Footwear and Stress Fractures .” Clinics in Sports Medicine , vol. 16, no. 2, 1 Apr. 1997, pp. 249–257., www.sciencedirect.com/science/article/abs/pii/S027859190570020X.
Hreljac, Alan. “Impact and Overuse Injuries in Runners.” Medicine & Science in Sports & Exercise, 2004, pp. 845–849., doi:10.1249/01.mss.0000126803.66636.dd.
Knobloch, K., Yoon, U., & Vogt, P. M. (2008). Acute and Overuse Injuries Correlated to Hours of Training in Master Running Athletes. Foot & Ankle International, 29(7), 671–676. https://doi.org/10.3113/FAI.2008.0671
Murphy, K., Curry, E.J. & Matzkin, E.G. Barefoot Running: Does It Prevent Injuries?. Sports Med 43, 1131–1138 (2013). https://doi.org/10.1007/s40279-013-0093-2
“Nike Air VaporMax Reveals the Pinnacle of Air.” Nike News, 20 Feb. 2017, news.nike.com/news/air-max-vapor.
Reid Bean, Rachel Christy; Schwartz, Gregory; Albertus, Yumna; Prins, Danielle; and Tam, Nicholas (2017) “RISK OF INJURY IN TRAIL RUNNING: A PRELIMINARY STUDY,” ISBS Proceedings Archive: Vol. 35 : Iss. 1 , Article 96.
Patents:
Huang, Ing-Chung. Air Cushion Shoe Sole . https://patents.google.com/patent/US4670995?oq=footwear+air+cushioning
Jessiman , Alexander W, et al. Support and Cushioning System for Footwear. 2003. https://patents.google.com/patent/EP0876113B1/en?q=support+cushioning+system+article+footwear+air&oq=support+and+cushioning+system+for+an+article+of+footwear+air
Marvin , William, et al. Shoe Having an Inflatable Bladder. 2012. https://patents.google.com/patent/US20190269202A1/en?q=A43B13%2f206
Passke, Joel, et al. Article of Footwear Incorporating a Fluid System . 18 Oct. 2011. https://patents.google.com/patent/US8037623
Potter, Daniel R. Shoe Having Adjustable Cushioning System . 18 Apr. 1995. https://patents.google.com/patent/US5406719A/en?q=A43B13%2f20
