Lara Bingle Worthington’s latest post-exercise selfie has everyone talking.

Lara Bingle Worthington has been relatively quiet on the Instagram front since the birth of her son Rocket Zot in late March.

For this reason it’s not uncommon for the Aussie model to get people talking each time she uploads a new photo — whether it features her little boy’s feet, the latest iteration of her famous “Bingle Bob“, or her equally famous husband Sam Worthington.

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Today, the 28-year-old has grabbed attention yet again with her latest post, only this time it’s the caption that’s done the trick. In the photo, Worthington is depicted posing in athletic gear with a very serious expression).

Her caption simply reads "18kms" with a tick emoji (for emphasis, naturally). Presumably, she's referring to 18 kilometres of running, which is an impressive feat — and the hundreds of followers who have left comments tend to agree.

What makes this more noteworthy is that Worthington, who has a beauty company called The Base, gave birth a little over three months ago. The thought of running (or cycling) that distance is daunting enough, let alone following one of the most transformative processes your body can go through.

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Running's not the only way Worthington has been keeping fit — last month she posted a video of herself doing strength training with an instructor, which she captioned, "Feels good to be back". The Cronulla-born model has always been health-conscious, so it's not surprising she was itching to get back into the swing of things post-baby.

According to Natasha Vasilevski, accredited Personal Trainer with Fernwood Fitness, it's generally best to wait between four and six weeks post-birth before you ease back into any high-impact, aerobic exercises like running. (Post continues after gallery.)

"My recommendation would be giving it to the six-week mark to fully heal from what you've been through, although that's dependent on a normal, healthy delivery with no complications," Vasilevski says. As with just about everything, every woman's situation will be different.

This delay allows the core muscles and the pelvic floor to heal and re-stabilise after the experience of supporting a developing baby for nine months and then giving birth.

RELATED: 5 things every pregnant woman needs to know about exercise.

Within this timeframe, Vasilevski advises sticking to low-impact exercises focused on strengthening and correcting the muscles in the pelvic/adbominal region, which will help prepare your body for other forms of exercise. (Post continues after video.)

Then, when you feel ready to pound the pavement, she recommends you start slow, and remember it's not going to be easy to get back to your pre-natal capability within those early months.

In the wake of a Caesarian section, a little more caution is required for runners. According to Becky Dyer, women’s health physiotherapist and co-creator of online post natal exercise program Body Beyond Birth, it's best to steer clear of any high-impact aerobic exercise for at least six months. “You definitely don’t want to go running, because it’s a lot of force through your pelvic floor, with the gravity and the pounding,” Dyer told The Glow.

RELATED: Everything you need to know about exercising after a C-section.

Unsurprisingly, a woman's ability to jump back into running or any other high-impact exercise after birth is largely dependent on her level of fitness prior to conception, and during pregnancy. Every woman is different, and so no two mothers will have identical fitness levels or capabilities after birth.

"The fitter you are, the better foundation you have before giving birth to get there quicker post-birth," Vasilevski says.

Vasilevski has seen clients who were still running and doing gym classes eight months into their pregnancy; on the flip side, if a mother has led a generally sedentary lifestyle then decides to take up running after giving birth, she will need to approach things more slowly and carefully.

RELATED: The 6 truths about running after having a baby.

Presumably, Lara Bingle Worthington was also fit and active during her own pregnancy, so an 18km run is going to be more achievable for her than it would be for someone whose lifestyle is less active. You don't need to put undue pressure on yourself — any physical exercise is going to be beneficial, and it doesn't have to be a marathon. And remember, you just gave birth. Your body has been through a lot.

Regardless of your fitness level, Vasilevski says it's important to seek guidance of a personal trainer or other accredited fitness expert when getting back into your regimen — as well as getting the green light from your obstetrician, as any pregnancy or post-natal issues will need to be taken into account.

When you do get back into running, Vasilevski says it's important to monitor your heart rate — if you go to a gym, a fitness professional can help you with this — and pay attention to how you feel while you're working out.

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"If you feel light-headed, faint or there's dizziness, nausea, pulling or strain, then stop," she advises.

When did you start exercising post-birth? What was your favourite workout?