The question of whether running makes abdominal muscles sore often stems from confusing general midsection fatigue with muscle damage. Many runners feel discomfort or a tired, weak sensation in their core after a run, leading them to wonder if they have achieved a full workout comparable to crunches. This article clarifies the distinction between the core’s stabilizing role and the type of strain that causes true muscle soreness.
The Core’s Stabilizing Role in Running
The primary function of the abdominal and deep core muscles during running is not to create movement but to prevent unwanted movement. Running is essentially a repeated series of single-leg hops, which constantly threatens to destabilize the torso and pelvis. The deep core muscles, including the transverse abdominis and the obliques, engage to resist this rotational force, a mechanism known as anti-rotation.
As the arms swing in opposition to the legs, significant rotational forces are generated. The core must cancel these forces out to maintain an efficient, forward-moving stride. This engagement acts like a rigid corset, ensuring that the power generated by the lower body transfers into forward momentum rather than being wasted in excessive motion. The constant, isometric bracing required for miles places a high endurance demand on these stabilizing muscles.
Distinguishing Muscle Fatigue from Delayed Onset Muscle Soreness
The discomfort experienced in the abdominal area after running is typically muscle fatigue, rather than the deep ache of Delayed Onset Muscle Soreness (DOMS). Muscle fatigue is a tired sensation that occurs when muscles are worked for a prolonged period. DOMS is caused by microscopic tears in the muscle fibers, usually resulting from eccentric contractions or high-force movements. The abdominal muscles, particularly the rectus abdominis, do not perform these movements during running, which primarily demands endurance and stability.
While running engages the rectus abdominis as part of the total core unit, its primary role is bracing, not the intense flexion required to induce significant DOMS. True abdominal DOMS is uncommon unless a runner’s form involves excessive hyperextension or flexion that forces the muscle to lengthen and contract under heavy load. Therefore, the common feeling is a temporary weakness or burning sensation from sustained effort, not the debilitating soreness that peaks one to three days later.
Addressing Other Causes of Midsection Discomfort
Midsection discomfort that runners often mistake for “sore abs” can frequently be traced to non-muscular or non-stabilizing issues. One of the most common is Exercise-related Transient Abdominal Pain (ETAP), commonly known as a side stitch. This is a sharp pain often felt just under the ribs, thought to be related to irritation of the parietal peritoneum, the membrane lining the abdominal cavity. This irritation is possibly aggravated by the mechanical jostling of internal organs during the repeated impact of running.
Gastrointestinal (GI) distress, often termed “runner’s stomach,” is another frequent cause of abdominal cramping and discomfort. This occurs because the body diverts blood flow away from the digestive tract to prioritize working muscles, which impairs digestion. Factors like dehydration, improper nutrition timing, or consuming high-fiber or high-sugar foods before a run can also exacerbate cramping and other GI symptoms. Poor running posture can also contribute to pain by straining the lower back or hip flexors, which may radiate discomfort into the abdominal region.