Corporate Fitness and Active Aging

Footwear is one of the most essential pieces of equipment for anyone who participates in many forms of exercise, whether for recreational purposes or as a competitive athlete. While it may seem like a simple piece of equipment, running shoes are designed with advanced materials and proper biomechanical stability in mind, aimed at enhancing performance, reducing injury risk, and providing comfort. The right pair of shoes can significantly affect a person's exercise experience. Understanding the various factors that go into their design is necessary when deciding on the next pair of shoes.

Key Components of Footwear

Running shoes typically consist of several key components: the upper, the midsole, the outsole, and the insole. Each of these parts serves a unique purpose. Whether it be to provide stability, cushioning, durability, or responsiveness.

1. Upper: The upper part of the shoe is typically made from lightweight, breathable materials, such as mesh or synthetic fabrics, designed to keep the foot cool and comfortable. The upper also plays a significant role in the fit and support of the shoe. This is where the laces lock onto to hold the foot in place within the shoe.
2. Midsole: The midsole is perhaps the most critical part of the shoe, as it directly affects the shoe’s cushioning and responsiveness. Materials like EVA (ethylene-vinyl acetate) foam, Nike’s Zoom X foam, or Adidas Lightstrike Pro foam are cushioning technologies are used in the midsole to absorb the impact of each foot strike and provide energy return during toe-off. A well-cushioned midsole can reduce the shock transferred to the joints and muscles, helping prevent injuries such as stress fractures or muscle strains.
3. Outsole: The outsole is the part of the shoe that comes into direct contact with the ground. Usually made from durable rubber, the outsole is designed to offer traction and protect the shoe from wear and tear. The tread pattern on the outsole can vary depending on the type of shoe, with shoes for trails featuring more aggressive designs for better grip, while road shoes typically have a smoother tread for more efficient movement on flat surfaces.
4. Insole: The insole is the layer inside the shoe that sits directly under the foot. It provides an additional layer of cushioning and can be made from foam or gel materials for extra comfort. Insoles can also be customized or replaced to accommodate specific foot shapes or arch types, offering greater support and preventing discomfort.

Some of the more elite running shoes offer different plates that can be incorporated into the midsole. Training based shoes can have nylon or plastic plates and rods to increase elastic energy return, but some have carbon plates in them as well. Most racing shoes have carbon fiber plates located in the hyperresponsive midsole materials to fully maximize energy return on toe-off.

The Role of Cushioning in Shoes

One of the most important factors in footwear is cushioning. Running produces significant forces that are absorbed by the body with each foot strike. Without adequate cushioning, these forces can lead to discomfort and injury. Cushioning systems are designed to reduce the impact forces and provide shock absorption. Below are three graphs showing the ground reaction forces for the three types of foot striking when running. Graph (a) shows the forces put back onto the foot from the ground after a foot strike. Graph (b) shows a midfoot strike. Graph (c) shows a forefoot strike. All these graphs show a high peak, which is over two times the person's bodyweight in force with each step. This gets higher as you start to move toward the front of the foot more, but it you also lose the initial shock from the heel and midfoot. 

Shoe Specs to Consider

When thinking about buying a new pair of shoes there are some important things to consider about each pair before taking them home. Some of these are based around personal goals and training methods, for instance, comfort and cushion or responsiveness and energy return. Other information that is good to know when looking:

1. Weight: How heavy the shoes are can make a difference in distances and times. Not to mention the extra fatigue it can put on the legs as time goes on.
2. Stack Height: Stack height refers to the thickness of the foam underneath the foot at the thickest point. This is measured in millimeters. Many shoes now offer a high stack height that can be both comfortable and responsive. In many competitive road races, the stack height on a shoe is capped at 40mm and on the track it is capped at 20-25mm depending on the race.
3. Heel to Toe Drop: This is talking about the difference in thickness between the heel and forefoot of the shoe. Standard is usually sitting at the 8mm For example, the Nike Vaporfly 3 has a tall heel stack height of 40mm and a forefoot stack height of 32mm the difference between those two numbers makes up the difference giving you the heel to toe drop.

4. Personal Feel: A lot of times what buying a shoe comes down to is how it feels. Going into the store and trying it on is what can either sell a shoe or turn someone away from a shoe.