One of the things that seems to surprise a lot of my new postnatal clients is when I advise them on appropriate timelines before they start running again. In fact, a lot of mums I see had listed getting out for runs as one of their main planned activities to help shed weight post-childbirth. The common assumption is that once you have had your 6 week check, all exercise is OK. Even some well known organisations still suggest that once you have had your 6 week check you can start higher impact exercise such as running. I’m afraid this is an over simplification and not in line with the guidance we as movement specialists and fitness professionals give to our clients.
Women’s health fitness instructors and physios simply saying “Don’t run until you are at least 3-6 months postnatal” isn’t all that helpful either. If we are encouraging Mums to take ownership of their own bodies and wellbeing, we need to be providing information and support, not simply a list of do’s and don’ts. So here’s a little bit of explanation why I advise my Mums to wait until they are at least 3-6 months postnatal before returning to running, and how to take a progressive approach when the time is right.
WHY IS RUNNING CONSIDERED HIGH IMPACT?
The Ground Reaction Force (GRF) is the force exerted by the ground on a body in contact with it. When running at a moderate speed (11 km/hr or 6.8 miles/hr), estimated ground reaction forces of between 1.6 - 2.5 times body weight occur (Gottschall JS & Kram R 2005). This gives you an idea of the impact experienced by the body when you run.
Some of you reading this might wear a fitness tracker when running, in which case you will see the number of steps you take in an average run. For a 3 mile run at moderate speed, you could be taking as many as 4500 steps (VeryWellFit.com). That is 4500 times that increased forces are applied through the body! That impact is going to be felt throughout the body including at the joints, particularly the ankles and knees, the pelvis, spine, plus through the pelvic floor and abdominal musculature.
So let’s think about some of these areas in more detail
THE PELVIC FLOOR
The first thing I will say here is that if you are reading this thinking “my pelvic floor seems fine, this doesn’t apply to me, I’m off for a run”, hold on and keep reading.
At least some of the impact of each ground strike in your run will be absorbed by the pelvic floor. Those repetitive ground strikes give rise to increased pressure through the abdomen and pelvic region. Therefore your pelvic floor needs to be functioning well to be able to react to these sudden increases, performing its function in supporting the pelvic organs and maintaining continence.
So you are early postnatal, you took a quick jog round the block this morning, and you didn’t wet yourself, hooray! So does that mean all is well down there and you are OK to get straight back to running 5K, 10K…? No, not really. You see pelvic floor dysfunction isn’t always something that presents symptoms immediately after childbirth. It is something that, if not addressed, can worsen and start to show symptoms over time. That repetitive pressure exerted on the pelvic floor with each ground strike can, overtime, further weaken a pelvic floor that is not functioning well. You may start to experience leaking during or towards the end of your run, or even develop pelvic organ prolapse.
Pelvic Floor First, an initiative of the Continence Foundation of Australia, use a great analogy of a boat in water to explain how prolapse can develop. They imagine the pelvic organs as a boat, the pelvic floor as the water level, and the supporting ligaments as ropes attaching the boat to the jetty. When the pelvic floor is functioning well, the water level is normal and there is very little tension on the ropes. However after childbirth the pelvic floor can be stretched and lose some of its resistance, so the water level is lower and the ropes are under increased tension. Imagine this persists, the ropes will overtime stretch and weaken, increasing the risk of prolapse. Now imagine adding jumping, running or bouncing activities. This can result in further over-stretching and weakening of the muscles and connective ligaments, thus increasing the risk of the pelvic organs dropping down and a prolapse occurring. I have seen too many women, some very young, who have prolapse and tell me it is because they starting running too early after childbirth. With this in mind, I encourage all new Mums to spend time working on pelvic floor restoration work before starting high impact activities such as running.
WHAT ABOUT THE REST OF THE BODY?
The pelvic floor is a significant factor when it comes to running post childbirth, but what about the impact on the rest of the body.
The repetitive impact of running can affect our joints, which may be less stable following childbirth due to laxity of the connective tissues. Also consider that, depending on how active you were towards the end of your pregnancy, your body may be slightly deconditioned compared to its pre-pregnancy state, and is very likely to be more fatigued now that you have a small human requiring your attention day and night.
Furthermore, if the abdominal muscles have not regained sufficient integrity and strength to properly support the lower back and pelvis you will be placing additional strain on the spine, opening yourself up to back pain and pelvic pain.
Running increases intra-abdominal pressure, which can exacerbate an abdominal separation. This is why I advise my ladies with Diastasis Recti to avoid running until they have been able to sufficiently restore the integrity of the abdominal musculature.
If muscles are weak, and ligaments lax, this compromises the framework of the body and may result in compromised form in our running. This can open us up for injuries, particularly those that can appear over time as a result of repetitive action with poor form or body mechanics, such as knee problems, hip bursitis, lower back pain etc.