The core is your body’s power source.
It’s in the core that forces are transferred from the legs to the upper body, adding oomph to a tennis serve or allowing you to hit a softball out of the infield. “You’re going to explode from your legs and rotate, and the momentum has to pass through the core. If you don’t have a strong core, you’ll lose strength and power,” said David Behm, a professor and exercise scientist at Memorial University of Newfoundland, who has been researching core fitness for 20 years.
Picking up a heavy box, or a kid, requires not just core strength but also endurance, he added. If core muscles are tired or weak, then the ligaments in your back take over and can get strained, causing back pain.
The core gives you stability, too.
To improve core endurance, Sivan Fagan, a Maryland-based fitness trainer, has her clients do exercises like side planks and dead bugs, which work deep muscles of the inner core like the pelvic floor muscles; the transverse abdominis, the innermost abdominal muscles that attach to the ribs, pelvis and spine; and the multifidi, an important set of back muscles that run along the spine and are key to spinal stability.
When these muscles are strong enough, she said, the pressure of exertion (from lifting a suitcase or digging in the garden) gets distributed throughout the core, which spares the spine from carrying too much load.
“You don’t want the lower back to do all the work,” Ms. Fagan said. “You want the core muscles to work together to stabilize the pelvis and the spine.”
While people commonly associate situps and crunches with the core, Ms. Fagan said they work only the external abdominals and none of those inner core muscles.
“Crunches don’t help with pressure distribution and core stability,” she said. “You can find people with a nice pronounced six-pack, but tell them to hold a plank in a good position and they can’t.”
