A lot of new runners believe that the more the run the faster they will become. What they don’t realize is that is only true when you first begin running. If you just started running and chances are you are slower than you would like to be but the more often and longer you run the sooner you get your body accustom to running. You may see huge improvements over the first few weeks or sometimes months but you will eventually hit a plateau. When you are doing long run after long run you are only improving your endurance. Your foot speed will not improve and sometimes if may even become slower. It will be quite a shock for you when you enter your first 5k when you see everyone taking off sprinting. You may think “oh they will come back” of “or they will die” and when you realize they are way ahead of you and you won’t catch them you may try to figure out what you did wrong. Chances are you didn’t do any speed or interval work.
If you want to run faster times it is very important and required that you do speed workouts. These are repeats at very face speeds. The distance, speed and amount of intervals depend on the race that you are training for. For example, if you are training on a 5k a workout where you do 10-20 ¼ mile repeats at 70% full speed is not uncommon. But when you train for a marathon you make be doing mile or 2 mile repeats. It is important to add in short and long intervals. For a 5k short sprints are good but make sure you also add in some longer intervals, like, ½ mile or ¾ repeats as well. I would recommend they are all faster than your 5k goal time and of course the shorter distance intervals will be done at a faster pace than the longer intervals. Don’t forget to add in a warm up and warm down before and after the speed workout.
I would recommend creating a week long training program where you add in a hard, fast paced long distance run, followed by a speed workout day, then an easy distance run, speed day, and easy long run, hard long run, and ending with a rest day with some sprints. You can play around with workouts and find what works best for you but it is necessary that you incorporate speed workouts into your training if you want to lower your running times.