Understanding the Core Canister: Why It Matters in Pregnancy and Postpartum Training

When it comes to training during and after pregnancy, one of the most important — but often overlooked — systems in the body is the core canister.

But what exactly is it, and why does it matter so much?

What is the Core Canister?

The core canister is the unit that includes your abdominal wall, pelvic floor, diaphragm and spinal muscles. These structures work together to help you manage changes in abdominal pressure — the pressure that rises sharply during load and impact, like when you lift weights, jump, or run.

When the core canister is functioning well, it tolerates these rises in pressure without issue. When it's not, symptoms like leaking, pressure, pain or feelings of instability can start to appear.

How Pregnancy Changes the Core Canister

Pregnancy has a huge impact on the core canister, affecting each element in different ways:

• Biomechanical changes: As the bump grows, the weight shifts the pelvis into more of an anterior tilt. This increases the curve in the lower back (lordosis) and often leads to a compensatory increase in the upper back curve too.
• Respiratory changes: The diaphragm is pushed upwards by the expanding uterus. To keep breathing efficient, the rib cage flares out to create more space for the lungs.
• Pelvic floor changes: The pelvic floor muscles are lengthened by the weight of the uterus. Research shows that this increased resting length (happening as early as 12–16 weeks) makes it harder to get a strong contraction. Those with leaking during pregnancy have been shown to have weaker pelvic floors than those without (Hilde et al., 2012).
• Abdominal wall changes: 100% of women will develop diastasis rectus abdominis (DRA) by 36 weeks of pregnancy, meaning the abdominal muscles are stretched to around 115% of their resting length (Fan et al., 2020; Goncalves et al., 2015; Gilleard and Brown, 1966). This stretch impacts strength, control and pressure management.

These adaptations are necessary for pregnancy, but they also mean the core canister becomes a limiting factor for many athletes.

Why Managing the Core Canister Matters in Training

During pregnancy (and beyond), just because you can do something — like lifting a heavy deadlift — doesn’t always mean you should.

You might have the glute and hamstring strength to lift 100kg, but if your core canister can't manage the sharp rise in abdominal pressure safely, it could cause symptoms or issues down the line.

Understanding how the core canister works, how it responds to different movements, and how to manage pressure well is crucial for:

• Training safely through pregnancy
• Reducing injury risk
• Rebuilding strength and performance postpartum

It’s not about stopping training. It’s about adapting intelligently, scaling movements when needed, and supporting your body as it goes through some of the biggest changes it will ever experience.

The Bottom Line

Learning how to use your core canister efficiently during training is one of the biggest keys to maintaining performance during pregnancy and rebuilding it postpartum. Knowledge, awareness, and smart adjustments can make all the difference — both now and in the long run.