I have been doing the Alexander Technique for ~2 years now... and am a lighter and faster runner than I was 10 years ago!
Beginners and experienced runners are helped by the Alexander Technique.
You run like you sit. Sad but true. When you run, the pattern you practice all day in front of the computer comes with you and generally makes a negative contribution along the way; poor breathing, muscle imbalance, poor coordination and movement pattern and so on.
The Alexander Technique, by improving your day to day overall use of your self, will indirectly make you a better runner, much like a better diet will bring overall benefits to your general health.
The Technique helps you become more conscious and better connected to what you are doing when you run. This makes running more interesting and rewarding. It elevates it from being just a 'physical activity' to the level of creative self expression.
Developing a balanced pace and/or a level stride will make you enjoy running more.
The Alexander Technique helps you understand and incorporate coaching advice into your running more quickly and easily. For example it helps you translate and put the words 'run tall' into action correctly without unnecessary effort or tension.
Many runners injure themselves while lifting weights or stretching, activities which can otherwise be a positive contribution to running performance. The Technique provides the runner with a better internal guidance system which helps prevent injury whilst engaging in these activities.
You will find that a few Alexander lessons will encourage the good use of your body which in turn will make running safer and more enjoyable.