Work toward moving the power stroke of your stride behind you so that you push, not pull. To do this, work on these four areas.
1. Get tall. Assess your hip posture and start learning a new neutral balance.
2. Make sure you can move. Assess your hip extension and start stretching to improve your range of motion.
3. Build a better butt. Get your glutes activated and start strengthening them (just follow these steps to strengthening your body without working out).
4. Bring your arms back. Get your shoulders and arms back through stretching, mobilization, and cuing.
More: The 12 Secrets to Running Success