Diastasis recti (DR) is the separation of the rectus abdominis muscles, commonly known as the “six-pack” muscles, which is a frequent occurrence after pregnancy. This separation results from the stretching of the midline connective tissue, the linea alba, often leaving the abdominal wall weakened. The safety of traditional core exercises like planks depends entirely on the degree of separation and the individual’s ability to manage internal forces. This article explores the mechanics of this condition and provides guidance on safe core rehabilitation.
Understanding Diastasis Recti
Diastasis recti is the widening of the gap between the two sides of the rectus abdominis muscle along the linea alba, the fibrous structure connecting the abdominal muscles. During pregnancy, the growing uterus places significant pressure on the abdominal wall, causing this connective tissue to stretch and thin. Approximately 67% to 100% of people exhibit some degree of DR by the third trimester.
While most common in postpartum women, DR can also affect men and newborns. A separation is typically diagnosed when the gap is wider than 2.7 centimeters (about two finger-widths). Symptoms often include a visible bulge or “pooch” above or below the belly button. A key visual sign of a compromised core is “doming” or “coning,” where the abdomen protrudes into a ridge shape during exertion.
The Mechanics of Core Pressure
The core’s ability to heal and function relies heavily on managing intra-abdominal pressure (IAP). IAP is the pressure created within the abdominal cavity, a space enclosed by the diaphragm, the abdominal muscles, and the pelvic floor. When the core is properly engaged, the deep stabilizing muscles, primarily the transverse abdominis, work with the diaphragm and pelvic floor to contain this pressure. This coordinated action stabilizes the trunk and prevents excessive outward force.
Certain movements dramatically increase IAP, forcing internal contents outward. If the linea alba is already stretched and weakened, this increased pressure pushes against the compromised tissue, potentially worsening the separation. The visible sign of coning or doming indicates that the core is unable to manage the pressure load of the movement. If a movement causes the abdominal wall to bulge outward, it means the force is exceeding the capacity of the weakened tissues to contain it.
Planks and High-Pressure Movements
Planks are a prone isometric movement that requires significant recruitment of the rectus abdominis and can generate high intra-abdominal pressure. For an unhealed diastasis recti, the full-body tension required in a traditional plank often creates an unsafe challenge. This pressure forces the abdominal contents against the stretched linea alba, which is what causes the visible doming along the midline.
For this reason, standard planks are generally not recommended for individuals with an active or unhealed DR. The primary concern is the inability to maintain deep core engagement without bulging. Other movements that increase IAP and should be avoided or heavily modified include crunches, sit-ups, and heavy overhead lifting. If any exercise causes the abdominal wall to dome, it is a clear signal that the movement must be stopped or regressed to a simpler variation.
Safe Core Rehabilitation and Exercise Alternatives
The goal of core rehabilitation for DR is to strengthen the deep stabilizing muscles, particularly the transverse abdominis (TVA). The TVA acts like a natural corset, tightening the abdominal wall when properly activated. Exercises should prioritize deep muscle activation over forceful contraction of the outer muscles. Diaphragmatic breathing is a foundational exercise, helping the core system manage IAP by exhaling on exertion.
Safe alternatives often involve exercises performed while lying down, which reduces the load on the abdominal wall. Progression can involve movements that decrease the gravitational load. Examples of safe, low-load exercises include:
- Pelvic tilts
- Heel slides
- Toe taps
- Bird-dog
- Wall planks
- Elevated planks