While that may be a bit simplified, the study found three things that predict faster marathon times:
- Being Male. Men had faster race times than women runners
- Being Light. Runners with a low body weight relative to height ran faster
- Running Lots of Miles. Higher training mileage was correlated with faster race times
The surprising results were that years of running experience didn't have much effect on race times.
While you can't change your gender or your height, you can change the way you train for a marathon.
Check out Hal Higdon's Marathon Training Guide for a detailed running program.
Also See: Running Workouts section for other training plans.
Effects of physical and training characteristics on marathon performance
Medicine & Science in Sports & Exercise. Supplement, May 2007. Sarzynski, Mark A.; Frey, Jocelyn C.; Womack, Christopher J. FACSM; Pivarnik, James M. FACSM