PLANKS… The exercise we love to hate.
Sure, it builds stamina and endurance and gets the heart rate up but does it really target our “core” muscles? For the last ten or so years, the Plank has been considered a staple of any core strengthening program. With a strong core touted as being the holy grail of fitness.
We know that a strong core is important. Strength through the trunk muscles has been linked to a reduction in lower back pain and lower limb injuries. However, this same research has also shown that static exercises, i.e. Planks, are not the best way to recruit these muscles. Rather, exercises which involve movement and instability through the trunk are the best at recruiting and strengthening our middle section.
From a Physiotherapy perspective, the core refers to a group of muscles that surround the abdomen and support the spine and pelvis. They also maintain pelvic floor function and keep us upright to perform daily activities. The core consists of the diaphragm, the back ex tensors, the pelvic floor and the deep and superficial abdominals. Some Physiotherapists include the gluteal muscles and hip flexors as part of the core.
Why do I not love the Plank?
Planks increase pressure on the pelvic floor.
The static hold of the muscles in a Plank, often coupled with holding the breath, increases intra-abdominal pressure. This places increased load on the pelvic floor muscles. Bearing down on the muscles limits their potential to contract and therefore creates a weak point. In addition, this bearing down and breath holding trains a detrimental pattern in our brain and muscles. Not only will it affect the organs but this can carry over to things we do in everyday life. For people with conditions that may predispose them to weakness of the pelvic floor (e.g. postnatal and post-menopausal women or men post prostate surgery, bearing down on the pelvic floor can worsen urinary and bowel symptoms.)
Planks are not specific to sport or activities of daily living (ADL’s) Do you know any sports or jobs around the house where you stay as still as you possibly can for as many minutes as possible?
No. So why would you train your body that way? Specificity is the first principle of exercise training, whereby the exercises you do should be specific to the sport or activity you are training for. In most sports and for ADLs, dynamic movement between the pelvis and thorax is essential and necessary for pain free performance. However, a Plank encourages a “gluing together” of these two structures and therefore has poor correlation of strength to our sports and activities.
Increases pressure on the spinal joints
The Plank produces an over recruitment of the superficial abdominal and lower back muscles and this actually increases compression on the lumbar spine joints and discs. This can be particularly detrimental for those who have suffered an episode of lower back pain. Dynamic exercises should be encouraged in the rehabilitation of a lower back injury so that people do not become afraid of movement and the deeper, stabilising muscles of the core are preferentially recruited.