This is a simple to follow 14 week plan to build the important muscles used in running.
It requires access to simple gym equipment such as weights, leg press/leg extension/leg curl machines.

It will help to improve your form and reduce the chance of injury.

Only add weight to the movements when you can complete a full set without compromising your form.

On the notes at the start of each phase there is a table you can print out and use which will make the workout easier to follow.