Core exercises have become a staple for managing low back issues. However, there is a lot of confusion regarding which exercises to do and how to do the exercises. This post will discuss some of the common faults with core exercise programs and how to create an effective core exercise program.
The common thought is that you need to “strengthen your core” to prevent low back pain. While having adequate strength in the core muscles is important for the low back, building endurance appears to be more important. This is because the core muscles need to have the capacity to support the low back throughout the duration of an activity. A mild contraction of the core muscles provides a substantial increase in stability of the core, therefore, strength is usually not the issue with the core muscles.
To focus on building endurance in these muscles, we need to work these muscles using the aerobic energy system (the energy system that uses oxygen). Holding a muscle contraction will temporarily decrease the blood flow to the muscle which will limit the available oxygen to the muscle. The muscle will then switch to an energy system that doesn’t utilize oxygen, called the anaerobic energy system, which is the energy system used to build strength of the muscles and not endurance.
Therefore when we perform core exercises, we shouldn’t hold a contraction for longer than 10 seconds. After 10 seconds, the oxygen levels in the muscles drop and the muscles switch from aerobic to anaerobic (transitioning from improving endurance to strength). The pause in between 10 second holds can be very brief (1-2 seconds). As soon as you stop contracting the muscle, blood will rush into the muscles and re-oxygenate the tissues. Then you can start another contraction.
There is nothing wrong with holding a core exercise for longer than 10 seconds. The issue is that the exercise becomes less useful for the core and lower back. When we are training the core, we want the exercises to replicate the demands that will be placed on the muscles as closely as possible. Very rarely do we have to hold a contraction for longer than 10 seconds. Most activities (walking, running, throwing, lifting, etc…) require the muscles to cycle between contacting and relaxing quickly.
When we are designing a core exercise program, the general recommendation is to use a reverse pyramid program. The reverse pyramid programs begins with the most reps in the first set, then decreases with each following set. This strategy allows you to do less reps with better form as your muscles begin to fatigue. An example program for the core could look like this:
Planks: 3 x 10 seconds, 2 x 10 seconds, 1 x 10 seconds
Side planks: 3 x 10 seconds, 2 x 10 seconds, 1 x 10 seconds
Bridges: 3 x 10 seconds, 2 x 10 seconds, 1 x 10 seconds
Core exercises can be a useful part of a rehab program for the lower back. The keys to building an effective core exercise program are to focus on building endurance in the core muscles by holding the exercise for 10 seconds and to use a reverse pyramid design to emphasize form.