In recent years the plank has become the "Number 1" exercise for developing core strength and protecting the back from injury. It's an exercise that can be used by a wide variety of individuals and has a much lower incidence of injury associated with it than say a standard sit up or crunch. But how effective is it at developing core strength? Is it just an exercise that doesn't aggravate existing spinal/postural conditions?
What is Core Strength?
Another "buzz" word, core strength is heavily touted as the primary goal for most strength programmes in todays fitness industry. Most people incorrectly identify core strength as abdominal strength but it should really be used to describe the stability and strength of the spine as a whole. Thus, we you see an individual following a programme that heavily includes some abdominal and lower back work to promote core stability there is most certainly a deficiency in the programming. When talking about core stability we should think about all of the muscles that assist in supporting the spine, these include:
Cervical - upper back (rotators, extensors, lateral flexors, anterior flexors)
Thoracic - middle back (rotators, extensors, lateral flexors, anterior flexors)
Lumbar - lower back (rotators, extensors, lateral flexors, anterior flexors)
External and Internal Obliques
But we all know that there are many other factors that affect spinal alignment or posture. An individual with excessive anterior flexion through the shoulder girdle (rounded shoulders) is certainly having their posture affected. So we should also consider that shoulder position is another important factor in maintaining spine strength and alignment. This then opens up a whole new area of core strength - one in which we can view the musculature of the entire torso as "core muscles". And if our definition of core strength is to maintain good posture and spinal alignment then this is entirely correct. So, we can also include:
A slightly different view of core strength but I hope you can appreciate this integrated approach.
Biomechanical Assessment of the Plank
I will keep this section purposefully simple. The plank, in which we are required to maintain neutral spine under load in the prone position, can achieve the aim of activating core muscles. The characteristics are as follows:
Lack of movement through the pelvis/spine
Weight supported through the arms
Position is prone
If we accept that, in exercise terms, we generally improve in the specific areas we focus on then the plank would achieve the following:
We would improve our ability to activate core muscles and maintain a stable postural position
We would become strong in the prone position
The arms would become better at supporting our body weight
This is where we can start to see that the plank has some flaws. Improving strength in a prone position has a very limited application for the general population. In fact most of us display postural problems in the following situations:
Standing for extended periods of time
Picking up a load from the floor
Twisting while holding a load
Twisting without a load
Lifting something above the head
While I certainly didn't want to go ahead and bash the Plank as an exercise (I programme it myself), I did want to raise the point that it's important that we qualify the exercises that we select for our own programmes and the programmes of others. I think the Plank has it's place but I certainly don't class it as the best or most effective exercise for most individuals.
Take a look at the exercises that you are currently practising and try to ascertain the precise benefits that they provide for you. Is it appropriate to progress or regress the exercise? Have you selected an exercise based on it's proposed benefits rather than it being right for you?