Ian, this same question was just recently discussed on the forum at the following location:
http://fastrunningblog.com/forum/index.php/topic,880.msg7914.html#msg7914I transitioned to a midfoot strike when I started training for marathon distance and to be more competitive. It was a difficult transition for about the first month but then I started to really see the results. My pace increased and I have been able to avoid injury (mostly) ever since. Injury prevention is due to the fact that when you land midfoot, your muscles can absorb more of the impact rather than all the energy going right into your skeletal system (and thus knees, hips, etc.).
The pace improve comes from the combination of your foot turnover and power that you impart to the ground. By increasing you turnover and increasing your power (exemplified by the "toe off" you push when you run, or your "kick") you increase you pace. More power lengthens your "stride" by making each footfall be that much further apart, thus increasing your distance between each step. This, and not taking huge strides, is how you increase your actual stride length.
It is difficult to put it all together. I started by increasing my turnover...I inserted and extra step in my cadence and kept my footfalls under my center of gravity more (felt like taking baby steps at first). So, I started with a 1-2-3 cadence every 1.5 second and changed to a 1-2-3-4 cadence. In a race, my turnover rate now is more like 190-200 strikes per minute.
After about a month, this started to feel more normal. Once I had it feeling more natural, I focused a lot on my power (toe/kick/etc.) to improve the feel of pushing harder on the ground. Then I worked to combine the two factors to improve my performance. This took some time but now is second nature.
In addition, other little things can improve your overall efficiency:
- Do not cross your arms in front of your body when running, move them forward to gain momentum in the upper body
- Don't clench fists while running
- Stand erect when running with a slight lean forward (controlled fall forward, or pushing forward with your stomach)
- Head tilt should be slightly forward
- Relax your shoulders to keep proper form and not stressing muscles
I hope any of this helps, it worked for me but everyone is different and has a unique form to themselves.