Does core training improve athletic ability?
The “core” has many different definitions. For some we would be talking about the area between the pelvis and the ribs. Some will go as far as between the knees and the shoulders. Some will talk about the inner and outer core, local and global core musculature and so on. Regardless of your own definition, if you’ve been involved in strength training or the fitness industry in any way over the last decade you will almost certainly have been caught up in the “core training” fad. Certainly for a while there if you were caught doing any exercise that wasn’t directly training the core you could expect to be ostracized from the herd. Conversely you could justify doing just about anything in the gym if you cited the activation of your transverse abdominis. Program design was also based almost completely around direct training of the core and most trainers had a swiss ball permanently embedded under their arm. The bench press became the swiss ball bench press. The row became the swiss ball row. You’d even see people defiling the squat on a swiss ball - all in the name of core activation.
But does it actually do what it says on the tin?
One of the most cited reasons for performing core training is that the core forms a transition area between force generated by the lower limbs from the ground to the upper limbs (and vice-versa in some cases). It was proposed that any weakness in the core would result in the dissipation of energy sometimes termed as power leakage. Thus it has been said that a stronger core = more explosive athletes.
A study published in September 2012 by J. Schilling et al. in the Journal of Bodywork and Movement Therapies investigated whether this was true. Specifically they studied whether core isometric endurance exercises (static exercises) or core isotonic strengthening exercises (dynamic exercises) were more effective at bringing about positive changes in athletic performance.
The researchers randomly assigned untrained college students into either the isometric group or the isotonic group. The isometric group were prescribed the curl-up, side bridge and bird dog while the isotonic group were prescribed the bent knee sit-up, cross curl-up and trunk extension. Both groups performed the exercises twice a week for 6 weeks.
The researchers tested all subjects in various endurance and athletic performance variables before and after the intervention, including a vertical jump test, an agility test, a 10 yard sprint, a 3RM machine bench press, a 3RM back squat as well as three core muscle endurance tests.
There was no significant change in terms of athletic performance in either the isotonic or isometric group as measured by vertical jump, 10m sprint or agility test. There were some minor positive changes in bench press and squat performance as well as the measures of core endurance.
Schilling et al. concluded that this study challenges any claims that specifically training the core will lead to any advances in athletic performance, at least as measured by vertical jump, sprint or agility tests.
Where do we stand?
Firstly if you’re looking for a reason to train the core then it would appear that getting faster, jumping higher, or becoming more agile may not be backed up by science. This isn’t the first study out there that would suggest this. In 2011 Sharrock et al. published an article in the International Journal of Sports Physical Therapy, which found a correlation between core strength (as measured by a double leg lowering test) and the overhead medicine ball throw but found no correlation with tests of speed, jumping ability or agility. Instead aspiring athletes looking for an edge would be better directed towards mastering the traditional powerlifting methods and/or Olympic weightlifting derivatives with appropriately programmed plyometrics (once strong enough), which have shown time and time again to improve athletic performance as measured by speed and jumping ability etc.
However there are of course other reasons to train the core - even if improving athletic performance may not be one of them. For example there are numerous studies that indicate that training the core may reduce the incidence of injury - particularly injuries to the lower back, ACL, hamstrings and hernia type injuries. When you consider that around 25% of the working population experience issues with lower back pain it couldn’t be a bad thing to add at least some element of direct core training.
But there is an ongoing debate in the strength and conditioning community as to what is the best form of core training. Some say that specialized core training is not necessary in a program which includes multi-joint, whole body movements like squats, deadlifts, overhead presses, snatch etc, since those exercises are also known engage the core musculature to a large extent.
A study by Hamlyn et al. in the Journal of Strength and Conditioning Research found that using traditional squat and deadlift protocols (<80% 1RM) brought about very high activation of trunk stabilizing musculature as measured by electromyography (EMG) and suggested that there may be no benefit to calisthenic type direct core exercises when adopting this type of training. The deadlift has been shown score much higher EMG readings than a plank when it comes to activation of the rectus abdominis, external obliques and lumbar erectors. The chin-up has also been shown to record as much as 5 times higher EMG readings from the rectus abdominis (6-pack) when compared to a crunch (we hate crunches by the way - more on this in another post). Certainly the infamous Bulgarian weightlifters of old were noted for doing no direct core work and they didn’t seem to struggle...
But there is an issue of balance. If we simplify the core into the muscles of the lower back, the abs, the left lateral stabilizers, and the right lateral stabilizers then we would want each to be balanced in terms of strength in order to maintain proper spinal posture and for each part to do their requisite amount of work. I.e. we want the strength of our core to be balanced front to back and side to side. Doing for example deadlifts will indeed activate our entire core - but it will not do so in a balanced fashion. EMG studies have shown that while a deadlift will indeed activate the rectus abdominis to a greater extent than say a plank, it will also engage the lumbar erectors in the lower back almost twice as much as the rectus abdominis. Similarly a front squat will engage the lumbar erectors almost 5 times harder than the rectus abdominis.
Conversely some of the best exercises for selectively training the rectus abdominis are hanging leg raises, ab roll-outs and dragon flags. While each repetition is shown to engage the rectus abdominis to a large extent, there is very little activation recorded in the lumbar erectors and so we often program those exercises into our sessions to offset the amount of training the lumbar erectors are getting from squats and deadlifts. This helps us to maintain balance in our core training.
This is just one of many interactions we are mindful of when designing our programs at Primal Strength. We will bring more information on this as the months go by but for now we would say - yes do core work but don’t assume it’s making you more athletic. Instead focus on perfecting the traditional compound lifts like the Olympic style lifting, squats, deadlifts, presses, rows etc and supplement them with deliberately chosen core exercises to maintain strength and balance in the core.
Sharrock, C., Cropper, J., Mostad, J., Johnson, M., Malone, T. A Pilot Study of Core Stability and Athletic Performance: Is There a Relationship? International Journal of Sports Physical Therapy. June 2011. 6(2), 63-74.
Effect of core strength and endurance training on performance in college students: Randomized pilot study, by Schilling, Murphy, Bonney and Thich, in Journal of Bodywork & Movement Therapies, 2012
NICOLLE HAMLYN,1 DAVID G. BEHM,1 AND WARREN B. YOUNG
Trunk muscle activation during dynamic weight training exercises and isometric instability activities. Journal of Strength and Conditioning Research, 2007, 21(4), 1108–1112 2007 National Strength & Conditioning Association