Does CrossFit increase the risk of developing POP?
Perhaps no other exercise modality is more polarizing than CrossFit. Depending on who you ask, CrossFit is either the best thing since sliced bread(lifts🥁😂) or equivalent to reaching inside your own pelvic cavity and yanking out your uterus (thanks, in part, to an unfortunate campaign about peeing).
But you know us - queens of the murky middle!
We're ready with (albeit-scant) research and conjecture to discuss whether CrossFit is a known risk factor of POP.
What is the connection between POP and exercise, according to the literature?
Of studies that examine exercise and POP, none support an association. This is counter to the popular opinion that identifies high impact and/or high intensity exercise as a causal factor of POP.
Some studies suggest that heavy occupational activity is associated with increased POP risk, and increased likelihood of undergoing POP surgery. However, these studies might be limited by not considering confounders, poorly defining occupational and activity histories, using non-standardized POP outcomes, and excluding household activities.
A cross-sectional study identified that middle-aged women who reported a significant volume of strenuous activity (21 hours/week or more - 3+ hours a day!) during their teenage years were more likely to demonstrate POP beyond the hymen during examination.
What about CrossFit, specifically?
A study evaluating pelvic floor symptoms in those performing CrossFit identified that the percentage of CrossFit participants experiencing symptoms of POP was consistent with other populations: 3.2%. (For reference, this study noted that the general population surveyed demonstrated a prevalence of POP symptoms of 3-6%). Notably, CrossFit does seem to be associated with an increased incidence of bothersome urinary incontinence. It is not known if CrossFit has a causal relationship to incontinence, however. While this research wasn't evaluating the risk of developing POP in the future or the presence of anatomical (but not symptomatic) POP, it appears that CrossFit does not increase the experience of POP symptoms.
Surely CrossFit increases pelvic floor descent?
A study evaluating pelvic floor strength and support compared groups made up of nulliparous women that typically performed non-strenuous activity (walking) to strenuous activity (CrossFit). Following an acute bout of activity, small decreases in pelvic support were identified in both groups, but the changes between the groups were similar despite the drastic differences between the two types of activity.
Would the changes be evident, or perhaps more pronounced in a population with POP?
Decreased pelvic floor support was also identified in a study looking at pelvic floor support following activity in those with POP awaiting surgical treatment. While most maintained the same POP-Q stage, 26% were found to increase in POP-Q stage following activity. None of the participants increased by more than one POP-Q stage. It is worth noting that the observed anatomical change was not correlated with the perception of increased symptoms.
The above research suggests that acute activity is associated with observable changes in pelvic floor support. This might suggest the effect of gravity and/or could be related to the finding that strenuous activity has been found to lower maximal voluntary contraction pressure, suggesting pelvic floor muscle fatigue, in nulliparous women with SUI, which may lead to observed decreases in pelvic floor support.
The nature of CrossFit being "constantly varied, high-intensity functional movement" makes it challenging to study and discuss as a singular activity. One WOD could vary greatly from the next, and the particular components of fitness that are within one's functional capacity could be unique to what another individual can tolerate well.
Is there a limit to what the pelvic floor can handle?
Research on individuals in the military suggest that there might be a limit to what the pelvic floor without POP can handle before exhibiting descent: amongst women doing summer basic training, those who attended paratrooper training were significantly more likely to have stage II prolapse at the end of the summer than those that did not. Unfortunately, this is the only piece of research that discusses POP expression during the (chronic) duration of a period of training. As paratrooper training likely exceeds the intensity and impact of the vast majority of recreational exercise, it is unclear how relevant this finding is.
The question of what the pelvic floor with preexisting POP can handle before it demonstrates an increased baseline of organ descent likely depends on an individual’s unique presentation of POP and the demands placed upon the pelvic floor.
Seeking to identify the absolute threshold of one’s pelvic floor capacity is likely a futile endeavor for several reasons. First, capacity fluctuates. What a person can handle on a given day is likely associated with factors such as pelvic floor muscle fatigue, hormonal status, digestive considerations, etc. Additionally, capacity can be expanded through training. Theoretically, as one’s strength and strategy shift, one’s ability to withstand various tasks likely changes, as well. Finally, we currently lack valid tools to predict one’s response in activities beyond what is currently testable. Seeking to establish one’s future abilities may lead to over- or underestimating one’s capacity.
High intensity and high impact exercise (like CrossFit) imposes a significant demand on the pelvic floor support system.
This imposed demand presents the opportunity for a training stimulus that could elicit positive adaptations, or a demand that exceeds that capacity of the pelvic floor, potentially leading to symptom provocation and increased dysfunction. In the event that the passive and active supports of the pelvic floor are unable to meet the demand placed upon them, the potential of increased descent of the pelvic support structures exists.