Posted by Steve Magness
Core training is all the buzz in almost every field of fitness. Search the internet and there have been massive amounts of literature written on the subject. As is a theme in my training, any time a ‘new’ thing becomes a fad, it is at first overemphasized until it naturally falls into its place of worth. That seems to be the case with core training. Is it useful for a distance runner or any athlete? Absolutely. Is it something that demands hours of time spent specifically training it? Probably not.
The problem arises in how best to train the core. Is it best to do hours of countless situps or wobble around on a bosu ball? Let’s look at some of the current research to see if we can discern what needs to be trained and how to train it.
A recent article was published comparing the degree of muscle activation of the “core” muscles (Behm, Cappa, & Power, 2009). They measured muscle activation for the external obliques, lower abdominals, and the eractor spinae. The interesting finding was that the level of activation of the eractor spinae was higher during running than during a back extension exercise designed to train that muscle. What this means is that running trains the core, specifically the trunk. One has to question if doing a ton of back extension work is a good exercise to train the trunk portion of the core, if you are getting more muscle activation just by running.
Similarly, if we look at muscle activation of the entire set of core muscles, what exercises provide the most muscle activation? Is it old school ab work like crunches, crazy yoga style poses, or new school stuff like doing ab work on Bosu balls. Again looking at muscle activation of several different core muscles during different exercises we can get an idea of what might be effective. In looking at two core muscles on the backside, the longissimus and the multifidus, their activation levels were much higher during a squat and deadlift at heavier weights than in several core exercises (bird dog, pelvic thrusts, planks, dead lift, pushups, bosu ball work). In looking at the external obliques, the level of activation was higher in the lifts than the majority of the core exercises and equal to the other two. The takeaway message is that for most of the core muscles, the level of activation is higher doing traditional lifting than specific core work.
Lastly, let’s look at training on unstable surfaces, which seems to be a new trend in athletics. Training on unstable surfaces like balance discs, BoSu balls, etc. creates a lot of problems. First off, training on an unstable surface increases the activation of the antagonist muscle. This isn’t a good thing. What this means is that the muscle working directly opposite of the muscle that is doing the work is activated. This obviously isn’t a desired outcome as it is in effect working against what you are trying to do. Essentially, this co-contraction is like driving with the parking break on. Training on an unstable surface doesn’t have a lot of research to back it up in terms of performance benefits.
The take away message isn’t that you shouldn’t do core training, it’s just that you should think about what you are doing as core training. As a distance runner, why would you try and replicate the same thing that gets done while running. Instead, focus on the benefits that you can’t get from running. . In this regard, it’s similar to weight lifting. Why spend time doing the same kind of training in the weight room as you do out running or on the track? That means forget the really high rep low weight exercises that do pretty much the same thing as going out and running. Instead focus on the things that you can’t get out running, in this example power/neural changes/economy changes. The same thing applies to core training.
Tieing this back to the original study which prompted this post, do we really need to spend an hour on doing a bunch of core work when running is core training? Will doing 15 back extension exercises do much when we just spent an hour doing an exercise which activates the back muscles to a greater degree? Instead, maybe we should do exercises which better strengthen those muscles if that’s the goal. Lastly, one has to look at how important the core is to your sport. Does a strong core really do all that people claim it too? Does our form really fall apart because our core does? That’s a common belief, but I’m betting that it isn’t true. Generally the core doesn’t fatigue first when racing. Form falling apart is a result of fatigue elsewhere and the runner trying to compensate or fight this fatigue by changing something. For instance, if stride length starts to decrease, you often see overswinging of the arm stroke. Are the arms fatigued? Not really, the runner’s just compensating. This can also be seen with the forward or backward lean during heavy fatigue. Is the runners back fatiguing so much that he can’t keep upright? Probably not, he’s just trying to compensate for reduced stride length/frequency.
A lot of the research in the above post was taken from a presentation from fellow grad student Matt Andre, so thank you Matt.