Strength Precedes Speed
By: Val Zeps
We all know that to race faster, you need to train faster. But running harder increases the chance of an acute injury. To reduce this chance of injury, one needs to be prepared to run harder ... this means getting stronger.
Hills are a good way to increase strength without the added muscle strains generated by running faster. This is why so many training programs have hills as an integral part of the base-phase of training. All this is done before you hit the track to do those short speed intervals.
Hills aren't the only kind of strength training. There are lots of different types of strength training plans that you can follow with or without weights. Do some research to determine which might work best for you.
Finally, as indicated in the linked article, if you are not logging enough miles, you are probably better off developing your aerobic system before delving into strength training if you want to get faster for 5k or above. But if you are ready to take that next step in your training and introduce speed work, proceed cautiously, and start working on your strength first.