Once you've started running regularly, it's likely you'll want to speed it up. There's plenty of ways that you can increase your mile time; however, you want to do it safely, or an injury could sideline you.
What matters most is consistency and proper form. Before you try to improve your mile time, make sure you've been running regularly to build a consistent fitness base.
Additionally, running with proper form will maximize your energy expenditure, allowing you to run faster. Keep your head up and your shoulders relaxed. Swing your arms forward and backward, rather than side to side. When your foot hits the ground, it should be on the mid-foot, rather than the heel.
Once you're running regularly and know you have good form, try a few more tactics to boost your speed.
Read More: Workouts to Increase Sprinting Speed
The only way to get faster is to practice running faster. However, you shouldn't make every run a a sprinting workout. Instead, make a weekly schedule that includes runs of varying intensities. One should be a short, fast sprint; the next, a little bit longer at a moderately high intensity; and a third that's longer still, which focuses on endurance. On days in between these targeted runs, do short and easy jogs (remember, consistency is key).
If you have a high school around you, head to the track after school's out for the day. Each lap around the track is a quarter of a mile, making it very easy to know how far you've gone in a certain amount of time. Using a stopwatch, run a lap to see how fast you can do it. Then, run it again, trying to beat that time. Continue to run laps until you just can't do it anymore. You can also run the straight parts of the track and walk or jog the curved sections to decrease the intensity slightly.
Do a Tempo Run
Tempo runs, which are faster-paced runs, improve your anaerobic threshold. This makes running faster feel easier because it increases the amount of time it takes for your muscles to fatigue due to lactic acid being released into the muscles.
To do a tempo run, start with a 5- to 10-minute warmup, and then run for 15 to 20 minutes at a pace that feels "comfortably hard." You shouldn't be able to carry a conversation, and if you have a heart rate monitor, aim to hit 85 percent to 90 percent of your max heart rate.
Take a Rest Day
The fastest way to injure yourself is with an overuse injury. In other words, take at least one day off per week to allow your body to recover. It seems crazy that resting will help you shave time off your mile speed; however, the workouts you're doing are hard on the body. The next day, you'll come back stronger and faster.
Read More: The Importance of Rest Days