While the crunch is one of the most popular exercises in the gym, it is also one of the worst exercises to do if you have a history of low-back pain. Lying face-up on the floor and curling the trunk to do a crunch or sit-up can exacerbate low-back pain for two reasons:
- Crunches can place a lot of pressure on the intervertebral discs of the lumbar spine. As the spine flexes to lift the trunk, the discs are compressed at the front (ventral portion), which pushes the back (dorsal) directly into the hard surface of the floor. This pressure can be even greater for people who exercise in the morning, because lying down all night reduces the gravity’s pull on the body, resulting in more fluid in the discs, which makes them more susceptible to injury if compressed during a crunch movement.
- One of the primary muscles that causes spinal flexion when pulling the upper body off the floor during a sit-up is the iliopsoas, whose primary job is creating flexion at the hip. If you’ve been sitting all day in a hips-flexed position (shortening the iliopsoas), doing an exercise that uses the hip flexors can make the muscle tighter and pull the lumbar attachments forward, causing more discomfort in the lower back.
Which Muscles Make Up the Core and What is Their Purpose?
There are many ways to describe which muscles make up the core, but here is the definition I use: any muscle that attaches to the pelvis or spine. From this point of view, core muscles can either provide stability to the spine or produce strength to create movement at the hips and trunk. When you look at the anatomical structure, the muscles of the human body are designed to be most effective when standing on the ground. If you want to know more about the specifics of how they work, you can read about that here andhere.
What Exercises Should I Do to Enhance Strength and Definition?
If your current training goal is to enhance strength and definition in your core muscles, instead of doing crunches or sit-ups, try the following exercises. They use all of your core muscles together, resulting in higher caloric burn.