A gymnasium can offer a great place to exercise and to run a mile, especially if the weather does not favor working out outdoors. However, if you want to run a certain distance, say, a mile, there are no clear markings inside telling you how far you've run. You have two ways to determine exactly how many times around the gym you need to run to achieve a mile distance.
Gymnasiums With a Basketball Court
Determine if the basketball court is regulation size for high school or NBA play. Note that college basketball courts are the same size as high school courts. If you are in a high school or college campus gym, the court is high school sized. If you are in an arena setting, it will likely be NBA sized. High school and college courts are 84 feet long and 50 feet wide. NBA courts are 94 feet long and 50 feet wide.
Take the length of the court and multiply it by two. Take the width of the court and multiply it by two. Add these two sums together. Then divide 5,280 -- the number of feet in a mile -- by the total you just reached. The formula is (2 x length) + (2 x width) = N. Then take 5,280/N to get the number of laps around the court that equal a mile.
Run around the sidelines of the court the number of laps found in Step 2. If the number is not even, for example 21.5, run 22 laps instead of 21 to account for slight variations in movement while running along the lines.
Gymnasiums Without a Basketball Court
Attach a pedometer to the waistband of your shorts. Set it to measure in miles. Note that some smartphones have applications that can be downloaded and used as a pedometer on your phone.
Start your run at one corner of the gym. Run the length of the gym. You can either run around the perimeter of the gym or run up and back the length of the gym.
Continue running until your pedometer or phone application indicates that you have completed one mile.
Warnings
Be careful when running because some gym floors can be slick, causing you to lose your traction.