I'm currently in marathon training mode and trying to improve my running form and speed in a number of ways. Mostly by trial and error. At the moment, I'm running between 5 and 14km in training sessions, but my long runs are going to get longer as the marathon gets nearer.
The issue I'm focused on at the moment is what to do with my "core" (or abdominal girdle) during long runs.
I've started using a slight lean forward at the shoulders to helps improve my speed. However, this changes how my body is positioned during the run and I'm not sure how to best work with this change.
I've taken to actively trying to engage or brace my abdominals (mostly the rectus abdominis) - imagine the feeling when you are at the top motion of a crunch, held for long periods and thats what I've been doing. Its worked of sorts, as I've noticed that occasionally after runs I get DOMS in my Abs. However, I'm not sure if its helping or hindering my running.
Does engaging like this pull blood away from other more vital areas during a run, such as the legs? Alternatively, does it help brace the spine to reduce back fatigue?
Basically, is it good or bad in the long run to brace the core during long runs? (Pun).