: Characteristics of the running shoe

 The type and wear of running shoes have been identified as risk factors for the development of overuse injuries. 

Proper shoe selection and fit can compensate for biomechanical abnormalities and decrease injury rates. 

Here are some reasons for athletes to select the wrong shoe

• Consumer demand
• Marketing
• Complexity of running shoe designs
• Celebrity endorsement
• Brand loyalty
• Style
• Impressive looking features and
• PRICE!

The optimum shoe for a runner is one that matches the runner’s specific mechanical features. 

Components of the running shoe

Upper

The tongue protects the foot from direct contact with the laces. It also assists the lacing system in providing a snug fit across the midfoot. Some examples of lacing systems are shown later. 1 

The insole sock liner is designed to increase cushioning and reduce friction. The sock liner is usually removable replacing the original insole can potentially decrease the risk of injury. 1 

The heel counter should be made of rigid, firm plastic to assist in rear foot stability. Although there is no evidence that the heel counter may not control rear foot motion, it is thought to be important for the stability and durability of the shoe. 2 A shoe with an overly flexible heel counter lacks resistance to overpronation and can result in injuries caused by internal tibial and femoral torsion. 1 

Forefoot flexibility

Forefoot flexibility must be adequate to allow easy motion of the foot flexing at toe off. With a rigid sole the calf muscles may need to perform extra work in order to plantarflex (point toes to floor i.e. heel raises) the foot during propulsion. 2 

Midsole

The midsole is the most important feature. They are usually made of EVA, which are light and a good shock absorber. The most important feature of the midsole is it should not be too hard or too soft. Midsoles that are too soft permit excessive mobility. 2 

Note: Midsoles that are flared promote rapid and excessive pronation of the foot and should be avoided. 

Last

Last construction refers to the method used to join the upper shoe to the midsole. Shoes are generally slip lasted where the upper is sewn together and glued directly into the sole. This promotes shoe flexibility but may reduce stability. In combination lasting the rear of the upper is glued to a fiber board which may promote stability, while the front of the shoe is slip lasted, maintaining forefoot flexibility. 2 Board lasting provides more rigidity and enhances motion control. 1 

Last shape (straight or curved) may offer a range of shoes to fit an individual and give comfort to many foot types.

Types of running shoe

Stability shoes have a good mix of cushioning, medial support and durability. These shoes are generally semi curved with a combination last. They often have a medial post or multidensity midsole to provide a degree of pronation control. Stability shoes are well suited to the midweight runner who has neutral pronation and medium to low arches. 1 

Motion-control shoes are the most rigid and are designed for limiting overpronation. Many have a straight last and board construction that offers stability and maximum medial support. These shoes tend to be the heaviest, most durable and most expensive shoes. Motion control shoes are geared toward the heavyweight overpronater who has flat arches. 1 

Cushioned shoes have the most flexibility, the softest midsole and the least medial support. Their midsole may include brand specific shock absorbing features i.e. Gel pads. They are built with a curved or semi curved shape and slip-lasted construction. These shoes are most appropriate for light-midweight runners who underpronate and have high arches. 1 

Lightweight shoes are designed for speed. They are constructed for basic cushioning and supports are often used for fast paced training or racing. High-performance, biomechanically neutral runners generally use these, because lightweight shoes may offer a kinematic advantage for training and competition. 1 

Table 1: A running shoe selection table. The left side lists the three basic foot types. The top rank lists the four categories of foot function observed during running. This table is intended to serve as an assistance in the selection of a running a shoe. 3

A patient who has high arches will often underpronate and will benefit from a curve lasted cushioned type shoe. These runners should avoid motion control or stability shoes. 

Runners who have flat arched hyper mobile feet are predisposed to overpronation. Low-to-flat arches are best fit with motion-control or stability shoes with firm mid-soles and straight-to-semi-curved lasts. Over-pronators should avoid cushioned type, curve-lasted shoes. 

Runners who have normal arches should wear either cushioned or stability shoes. If you have a normal arch and no biomechanical abnormalities a cushioned shoe is appropriate. If you have some mild-to-moderate pronation a stability shoe is a better choice. 1 

For evaluation of your footwear pattern you can wet your foot or put paint on your foot and print onto paper. Compare this to figure 4. reference 1

Lacing techniques

I found this on www.profeet.co.uk

          1                        2                           3                       4

1 – lacing for narrow feet

2 – lacing for high in-steps

3 – lacing for wide feet

4 – lacing for heel retention 

Running shoe care

• Wear running shoes for running only. Wearing running shoes for walking or playing others sports can break down the motion control and cushioning of your shoes.
• Don’t kick off your shoes without untying them, this will destroy the heel counter
• Avoid ruining in wet shoes, a wet midsole has 40% to 50% less shock absorbing capability
• Don’t wash running shoes in the clothes washer, this will deform their shape
• Exposure to excessive heat will degrade the components of the shoe. Let them dry naturally. 1

Running shoe replacement

• Excessively worn running shoes may lead to injury.
• Replace shoes every 400-600miles or every 6 months.
• Outsoles are poor indicators of reaming shoe life; the midsole will wear out long before the outsole.
• Midsole wear can be subtle and manifest by excessive wrinkles and compression of the sock liner.
• Running shoes may lose between 30% and 50% of their shock absorption after about 250 miles of use. Even sitting on a shelf their shock absorbing capabilities are significantly reduced after 1-2 years (Robert P. Wilder, MD, written communication July 8 2004.
• Alternating between two pairs of running shoes will extend the life of the midsole longer. 1

Note: For a proper fitted shoe there should be a thumbnail of extra space between the toe and shoe. 

Specialist running stores now have the technology to assess your running gait.

At Sweatshop, York they have, Adidas Foot Scan technology, to analyse running gait.  This ensures that everyone has a trainer that is right for his or her gait. A qualified member of staff to ensure the trainer works will look at the scan! They have an in store treadmill so the client can test the shoe for as long as they desire to make sure it is the shoe for them. Sweatshop York is located on Hull Road, at the Next Generation Health Club on St John's Playing Fields. 

References

1. Asplund, CA. Brown, DL. (2005). The running shoe prescription: Fit for performance. The Physician and Sportsmedicine. Vol 33 Issue 1.

2. Brukner P, Khan K. Clinical Sports Medicine. (2ED). (2001). McGraw Hill. Pages 91-93

3. www.spineuniverse.com table from Gallagher C. Institute for physical sport. A summary of shoe fit based on shape and function.