RUNNING SCIENCE, an associated specialist running shoe store, provided some invaluable information on the ‘life' of your running shoe.
If you consider that your feet strike the ground between 600 - 1,000 times per kilometre (depending on your pace) at 2.5 - 3.5 times your body weight while running, it follows that footwear plays a critical role in running enjoyment, performance and injury prevention.
Running shoes that are improperly sized, unsuitable for your biomechanics or training needs and/or have gone past their use-by date can cause injury. Researchers have shown a significant correlation between infrequent changes of running shoes and injuries.
What can you expect from your running shoe?
Essentially it is very dependant on how much time you spend in your running shoes. As a general rule a good shoe will allow you to enjoy approximately 900 - 1,100km of running.
Why do running shoes where out?
Research has demonstrated that the midsole material of a running shoe will last for approximately 700-1,000 kilometres or 6-12 months, depending on the mileage and intensity of training. The midsole provides the important cushioning and stability to a shoe, so once it has worn out the shoe loses its functional stability and increases your injury risk.
The outsole of a running shoe is made of durable compounds and is a poor indicator of remaining shoe life. In most cases, the midsole will wear out long before the outsole - especially for heavier runners.
Signs of Wear and Tear?
You need to examine the major areas of decomposition - the heel counter, the midsole and the outsole - any extrinsic abnormality causes an imbalance of impact forces and may increase the risk of injury to your lower limbs.
- Look at the heel counter - is there any wearing on the inside or outside? Wearing on the inside can actually promote over-pronation and its associated overuse injuries, while wearing on the outside can occur even with a normal running gait pattern.
- Look at the midsole - is there any excessive compression, wrinkling or tilting? Monitor the torsional (twisting) stability of the shoe. Hold either ends of the shoe and twist in opposite directions - is there too much flexibility?
- Look at the outsole - have you worn through the rubber to the midsole? Can you start to feel the irregularities of the ground under your feet?
Tips to Get the Most Out of your Shoes
- Reserve your running shoes for running only! Not gardening, bush-walking, cycling etc.
- Rotate your shoes: alternate between 2 pairs of running shoes so as to extend the life of the midsole beyond that of wearing each pair consecutively. Thus:
- Use one pair for longer runs and any ‘events' and the second pair only for shorter runs, inclement weather and any off-road runs.
- The first pair to reach 1000 km run, should be given a new job description, (i.e. gardening, fishing etc) and a new pair should be brought into the rotation.
- Asplund. C, Brown (2005), The Running Shoe Prescription. The Physician and Sports Medicine, 31(1)
Published by Balmain Sports Medicine