I think that we all understand how worn out running shoes reduce the quality of performance, and minimize the joy of the running experience. Now, lets talk about the accumulative effect of musculoskeletal impact.
If you like facts and figures, this will be interesting information.
To get an idea of what your running shoes do for you, lets looks at an "average 150 pound runner statistic".
• Each shoe lands on the ground 800 times for each mile. In a ten mile run, that is 8,000 times that each shoe hits the ground. You could get injured pretty easily with that many impacts with the ground.
• To calculate the total impact for each run; multiply the number of foot contacts by the runners weight. You'll see that a ten mile run has 600 TONS of impact (per foot). Another way of looking at this, is that a runner weighing 150 pounds has 500 pounds of stress (per square inch) on EACH foot at the point of impact.
• The impact becomes significantly higher if you are running down hill.
If you are not wearing the correct running shoe, or your shoe is over-due for replacement, your chance of injury becomes exponentially greater. The collective impact can cause significant damage to your feet, knees,hips, and back. Often times the physical damage may not be immediately realized. Be aware of "the collective effect" with your physical condition. It's similar to the "straw that broke the camel's back".
Using time, miles or both, is a pretty good way to know when it is time to replace your running shoes. But this is not always the easiest thing to do. Some runners write the date they started running in a shoe, on the side of the cushioned-sole of ach shoe. Based on their average weekly miles, they can mark a date on the calendar to replace the shoes. EXAMPLE: If you run an average of 20 miles every week, you'll divide 300 miles, or up to 500 miles by 20, to calculate the date you'll replace the shoes. In this example a 300 mile shoe will be replaced after 4 months. The 500 mile shoe will be replaced in approximately 6 months.
This gives you a calendar and miles prompt, but I still recommend coming into to see us at Inside Out Sports to see the shoe options. You'll never regret taking the time to review new shoe options... and it provides a great opportunity to visit with our staff.