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).

  • Hunching forward improves your speed? Nov 5, 2013 at 8:49

5 Answers 5


Trying to actively engage the core muscles is like trying to control your breathing. It can be done, but it's likely to hinder your progress. Unless you have such bad form that you need to think about it, you just want to run and let your core area take care of itself.

Generally for endurance running, you want things to be as relaxed as possible. Artificially leaning forward or back will place an unnatural stress on your body, unless as said you have really bad running form.

The vast majority of runners self select the stride length and foot strike pattern that best suits them, so unless you're having problems, just run and concentrate on the purpose of the workout rather than what your erector spinae might happen to be doing.


I'm not an expert either, but I've been running for a long time and have experimented with different techniques. These are my findings and things I try to keep in mind when distance running:

  • Hold your head up
  • Breath in through nose and mouth, out through mouth only
  • Don't lean too far forward
  • Don't bring the knees up too high
  • Bend arms 90 degrees at the elbow and relax your hands (pretend like you're holding a potato chip)
  • Push your belly out when inhaling, tighten when exhaling (this actually answers you question). The concept here is to aide in breathing and get the most out of your lung capacity.
  • Strike on the fore-/mid- foot

Again, these are just my personal preferences and of course you'll need to experiment to find out what works best for you.

  • How do you breathe out through the mouth only? And more and more studies are showing forefoot striking for endurance running increases injury rates. Also, high knees is actually a recommended running form. Watch some slow motion videos of Geb, Rupp, Hall, and note how high their knees come up.
    – JohnP
    Jan 5, 2014 at 5:33

I am not an expert on running, so it might be that someone more experienced will prove me wrong. But my (hopefully intelligent) guess would be that it is better to "relax".

When you're running, the hips and shoulders move and this will activate different parts of the abdominal muscles anyway, without you needing to think about it. Conscious tensioning, in my opinion would not improve performance unless you're an expert on working with the hips and activating/relaxing the different muscles in your abdomen independently. Eg. can you activate rectus abdominis while keeping the sides fully relaxed, can you tension one side while relaxing the other side etc. If you cannot do these then you'll likely keep everything tense which would make breathing more difficult, and push blood away from the abdomen (increased pressure pushes blood away), which is not healthy maintaining for longer periods. This video might explain better what I'm saying.


Big tip! Focusing on lifting your legs with your core helps me when doing half or full marathons. It is really hard to begin doing it, but after a couple of runs, it became natural to me. Also, doing what feels comfortable during long runs is usually what you should be doing. GOOD LUCK!


Your core mucles and visceral fat exist to protect your organs. To run and deliberately ignore your body's natural reaction to tighten up your abdominals would be like stripping your car of its shocks/struts. You want the brace of the muscles, but it also gives you traction move forward. Aim for maximum strides AND height if you can do both. Propelling power and the ability to land your foot farther is more distance travelled (and equals win!)

Sources: me - ex hardcore distance runner for my stature (5' competing against individuals with large advantage in stride due to their longer legs)

  • 1
    Longer and/or higher strides are not considered the most effective running style today! It will probably give you a slightly faster pace, but it will come at a rather high price in efficiency as 1) all energy going into the added height is almost completely lost as you land as the energy in not translated into forward motion but is absorbed in the various muzzles in the legs and 2) the longer stride also means you land exclusively on the heal and that leaves a fair deal of energy in the ligament and can lead to "Plantar fasciitis". Jun 5, 2014 at 19:46

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