The outsole design of running shoes is once thought to be monolithic with slight variation from a main theme where the thread pattern is tuned either for running on synthetic track or concrete and road surface. However, in recent years, Adidas has brought forth a revolution in thread design in running shoes that upended the view of the function and utility of running shoes. Meshed with the stress loading and locomotion pattern of walking cum the high stress typical of running, contemporary Adidas running shoes sport a thread pattern that not only deserve a close look at the aesthetic level, but also provide a useful lens into the role of sports science in articulating a functional philosophy in enhancing grip for running shoes.
Perhaps the most well known mid-tier running shoes from the Adidas product lineup is the Response Cushion line of running shoes, which was discontinued with the introduction of the last model in the series, Response Cushion 22. The Response Cushion family of products is marked by the use of three distinct technologies: adiprene midsole technology, Formotion heel counter pad, and torsion system, the last a technology for reducing the movement of the feet upon impact, thereby, reducing the incidence of injuries in athletes and casual runners.
Marking a departure from the design philosophy of Response Cushion, the new Adidas Galaxy 3 series come with an embedded Formotion pad at the forefoot and heel counter. Additionally, it also marks a dramatic change in the way Adidas views thread design of outsoles of shoes functionally catered for walking and running. Specifically, the outsole of Galaxy 3 is designed for neutral pronation runners and allows for shock absorption through a greater outsole surface area. Unique to the new one piece outsole design not available in high performance running shoes, Galaxy 3’s outsole enable shock absorption even in cases where the middle part of the outsole is used in landing on steps of staircase (Figure 1).
Figure 1: Innovative outsole design of Adidas Galaxy 3 featuring an embedded Formotion pad on the front and heel of the shoe. The one piece design of the outsole marks a distinct departure from the traditional design of two patch running shoe outsole.
Similar in design to the outsole of Adidas Galaxy 3, the outsole of Adidas Duramo 8 sports a useful addition in an innovative embedded torsion system first introduced in Adidas Galaxy 2. A significant evolution from the design of the full torsion system still available in Adidas performance running shoes such as Adidas Supernova Glide Boost and Adidas Sequence Boost, the embedded torsion system brings the important foot protection technology to the masses who likely will use the Duramo 8 as a walking cum light jogging shoe. One unique design element in the embedded formation pads of the Duramo 8’s outsole is the presence of white horizontal stretch lines that allow the outsole to slide a little, on impact with ground. This feature enables some of the downward impact energy to be dissipated through the sliding motion; thus, reducing the amount of shock transmitted to the knee.
Figure 2: Embedded torsion system (center of shoe) and two piece Formation pads are the major features of a new design trend in outsole useful for walking, jogging and cross training applications such as in Adidas Duramo 8. Balanced in thread pattern between the left and right side of the outsole meant that it is useful for neutral pronation runners.
Collectively, demand for walking shoes with foam layer in the midsole that helps to cushion shock arising from long distance walking or load bearing duties meant that there is a corresponding need to reshape the outsole to confer grip as well as absorb shock from impact with the ground. However, the short strides of walking together with the lower shock incurred provides a different design paradigm for creative exploration of the functional and design boundaries of walking cum jogging shoes. Specifically, to endow walking and jogging within a single shoe design demands an outsole that is durable and yet able to allow some sliding, which affords a release of energy that could otherwise be transmitted to the knee. Hence, Adidas has led the trend and the industry with a couple of sports science proven outsole designs that borrow and modify the best technologies from their line of high performance running shoes. One such technology is torsion system, which reduces the pronation (or movement) of the foot on impact with the ground. Implemented as a smaller and less capable embedded torsion system in the outsole and midsole of Adidas Duramo 8, the concept is likely to remain for the next few iterations of the product line. Additionally, the highly useful heel counter system in Adidas Response Cushion line of running shoes known as Formotion, is also given new life in Adidas Galaxy 3 and Adidas Duramo 8 as both forefoot and heel pads, which enhances the ability of the full length piece of foam in breaking a stride, and provides for a more efficient absorption of shock from walking and light jogging. Such affordable and durable shoes can easily lend their use as lifestyle shoes. The latter a new category increasingly finding a foothold in the sports goods market.
Category: sports science, sports medicine, health,
Tags: midsole, outsole, thread pattern, shock absorption, grip, torsion reduction, pronation,
Acknowledgement: Ng Wenfa thank Seah Kwi Shan for co-authoring this blog post.