Want better abs? The treadmill is a good start, but it's not the whole solution. A treadmill workout helps you burn fat to reveal taut abs, but won't noticeably overload the ab muscles to create definition and tone.
Certain abdominal muscles do act as stabilizers when you walk or run on the treadmill, as the abs form the foundation for movement from your hips, arms and legs. This stimulation can be beneficial, but not comprehensive, when it comes to creating a strong core.
Muscle Activation on the Treadmill
Unfortunately, when you walk on the treadmill, the muscles of your abdomen don't do a lot of work. The internal obliques, which form a deep internal V-shape within your trunk, remain in a state of tension to support the pelvis when you stand and walk.
But unless you're on an incline and/or including resistance, the rectus abdominis — which forms the front part of your abs — and the external obliques, at the sides of your abdomen, activate minimally.
The abs don't get worked as effectively during a run as they do from some traditional abdominal exercises, including the crunch. And, the more experienced you are as an runner reflects how your abdominals activate during running.
In a 2009 issue of Applied Physiology, Nutrition and Metabolism, triathletes and non-runners were asked to run on a treadmill, and the activation of their core muscles, including the external obliques and back extensors, were measured. The triathletes showed far more engagement of the external obliques during a run performed at 60 to 80 percent of their maximum heart rate compared to the non-runners.
Calisthenic-style abdominal curls were still more effective at training the abs for these athletes, but running proved more effective than back extensions in targeting back stabilizing muscles. The researchers concluded that running does provide some trunk endurance benefits, especially for trained athletes and their spine-supporting muscles.
Designing an Effective Abdominal Workout
The best abdominal training involves performing five to 10 exercises that move the torso in various ways: rotation, forward and back flexion and side-to-side flexion. A set of eight to 12 repetitions for each move is sufficient.
Some of the most effective abdominal exercises include the classic crunch, a decline-bench sit-up, bicycle crunches, stability ball crunches and the yoga boat pose, according to 2014 research from the American Council on Exercise.
Aim for three to five total abdominal workouts per week. Change up your routine every few weeks too, to keep your abdominals from getting accustomed to specific moves.
When you do perform ab exercises, focus on slow, controlled movement and visualize the contraction. Think about drawing the belly button toward the spine, for example. When you do include the crunch in your exercise routine, avoid rounding the neck in toward the chest.
Strengthen your abs when you finish your treadmill workout so you're already warmed up.