If you didn’t like algebra class, this article might not be for you. Do you remember this formula?
Distance = Rate x Time
Which can be rewritten: Time = Distance / Rate
For our purposes: we’ll state our Rate as inches per second.
Intending to run a faster 5km race, the distance is a constant number, and an increase in Rate will reduce our 5km time.
A 5km is 3.10686 miles or 196,850 inches. Let’s assume you run the shortest possible route (tangents and diagonals) to keep the distance as close as possible to that number.
To finish a 5km in 25 minutes, you must run 131 inches per second. To improve your finishing Time to 24 minutes, you only need to cover 6 inches more per second.
Only two factors are involved in speed, turnover and stride length.
An ideal turnover for endurance events would be 180 strides per minute (3 per second). The typical runner does not maintain this cadence. I’m closer to 170 strides per minute (2.83 per second). A 10-stride increase is easier to accomplish than the additional strength required for the longer stride length to cover the same distance in a minute.
Making a stride length longer requires more strength or better technique. As you tire, form worsens, muscles weaken, and stride length is reduced.
With a turnover of 2.83 strides per second, to cover 131 inches, a stride length would need to be 46 ¼ inches. The 137 inches at three strides per second, a stride length would need to be 45 2/3 inches. So a minute faster requires less strength.
An easy way to determine your turnover is to set your watch to a one-minute countdown timer. On an even surface (tracks are ideal), count the number of times your right foot (this doesn’t work with your left foot) strikes the ground in a minute. Multiply the results by two to get strides per minute.
If your number is less than 180, work on the track to reach 180. Once you have the feel of the cadence, practice until it becomes second nature. For those of a certain age, the tempo of My Sharona by The Knack is 180 beats per minute.
Are you running uphill? You will feel better and cover more distance with a quicker turnover than powering up.