#PTonICE Daily Show – Monday, June 24th, 2024 – What do we really know about strength training in pregnancy?

In today’s episode of the PT on ICE Daily Show, #ICEPelvic division leader Christina Prevett discusses

Take a listen to learn how to better serve this population of patients & athletes or check out the full show notes on our blog at www.ptonice.com/blog.

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Hello everybody and welcome to the PT on ICE Daily Show. My name is Christina Prevett. I am one of our lead faculty within our pelvic health division. Sorry for coming on here a little bit early. We are in the throes of young kids finishing school and trying to work around new schedules. So apologies for being a little bit early. But today what I wanted to talk to you all about was what do we really know about resistance training in pregnancy. And as many of you who have kind of followed the podcast in the past know, I’m a postdoctoral research fellow at the University of Alberta looking specifically at resistance training in pregnancy, which means that a big part of my job in my postdoctoral fellowship is to be very aware of the state of the literature and then where my role is as a person trying to build a program of research to be able to add to the existing body of literature. And I’m going to start this episode talking a little bit about my story getting into this because I think that it’s relevant. So my PhD research was in high load resistance training in a geriatric population. I love my older adults. You know that I’m part of the older adult division. And I had two children while I was going through my doctoral studies. I was going part time. And then I was also a national level weightlifter before I got pregnant with my daughter. So I was doing a lot of heavy resistance training during my pregnancy. And I had a committee meeting during my pregnancy talking about, you know, obviously that I was going to go off on that leave, et cetera. And one of my committee members, whose name is Stu Phillips, many of you know him from the protein metabolism and resistance training literature. He said, you know, Christina, if you think that there isn’t any research in loading the older adult appropriately, wolf when it comes to what we know in pregnancy. And I thought that was super fascinating and of course being the nerdy researcher that I am, I looked into the research and I recognized that he was right. And So I kind of want to talk today about what we truly do know, what the state of the literature is, a little bit about me trying to change that, I’m going to talk a little bit about some of my research studies, and then where we can go going forward. So we know in a general population that resistance training is one of the best things that we can do for our overall health. I don’t tend to try and put people into specific buckets that you have to exercise in a specific way because the best exercise is the one that you do. But in terms of longevity and maintaining independence into older age, supporting whatever exercise you like to do with resistance training is definitely a recommendation that I’m gonna make with a lot of passion. Whether you choose to prescribe to that exercise program or not, Resistance training is one of these exercise modalities that is going to allow us to have independence. It’s going to stave off a lot of chronic disease and musculoskeletal injury. And we know that, you know, the best exercise program is the one that we start as early in our life as possible and go into older adulthood. I’m going to try and put on as much muscle mass as I can before the age of 40 and then hold onto it for dear life into hopefully 100. And so we have a lot of really positive evidence for resistance training in a general, like reproductive age population, but then also into older adulthood. We’ve talked a lot about it in the Jerry segment. But when we don’t have evidence, right, around exercise, or we don’t have any evidence in any type of intervention in pregnancy, we freeze, right? And I say this all the time. If we don’t know, the answer is no. and when we aren’t sure we freeze, which is where bed rest and pelvic rest recommendations have come in when complications can creep up in pregnancy because we don’t really know what we can do, right? We’re not really sure what we can do. So we want to give a recommendation that we’re doing something. And so we pull people back from activities of daily living, sport, exercise and we say like, let’s not do anything because you know, there’s this complication happening. And where evidence is starting to show now is that many of our complications have pro-inflammatory cascades and therefore exercise might be a really important mitigating factor or modifiable influence on a person’s experience of complications during pregnancy. But the baseline is that if we don’t know that the answer is no. And so that knee jerk reaction has trickled into a lot of our recommendations around exercise in pregnancy and specifically around resistance training. So when we look at public perception of resistance training or exercise in pregnancy in general, it’s really interesting because aerobic training is generally seen as more positive as something that you’re doing to benefit the health of mom and baby. But there’s a lot of fear-focused messages that are put into the resistance training space. And gosh, we’ve seen this all the time, right? Like we see when a person lifts a heavy deadlift and they’re pregnant, like go into the comment sections and you just are gonna heave because you see everybody telling you that your baby’s gonna die and that you’re being reckless and all this type of thing. And so if we’re going to combat these messages, and we know that the perception is generally more negative because of a lot of fear and thoughts of danger around resistance training and pregnancy, we have to one, know where the state of the research is. And then two, we have to build levels of evidence that are going to gradually gain us more confidence and being able to remove some of those fears around resistance training. I’ve done podcast episodes before where I talk about risk tolerance of providers to allow individuals to flex their own decision making during pregnancy and how in low to moderate intensity exercise, we tend to feel very good in that risk tolerance zone, but where we get a little squeamish is in these higher intensity zones. Part of the reason for that is the state of the literature currently. So right now I can’t speak specifically to my results because I haven’t published this yet, but I am working on a systematic review on resistance training during pregnancy. And we have pulled about 50 studies on resistance training during pregnancy, which sounds like a lot, which it is. And it’s been a lot of work to get the systematic review under control. But what we have noticed and what I have seen over and over and over again is a couple of things about the resistance training literature. Number one is that we have very few studies that look at resistance training in isolation. And you may not think that’s necessarily a bad thing, because a lot of people are exercising in multiple modalities. Think about functional fitness, they’re doing aerobic training and resistance training. But when we know that there’s a lot of incurred benefit of aerobic training, especially when it’s dosed appropriately, there’s an interference effect that we see in the literature. So what I mean by that is that we know that there is benefits of aerobic training on rates of gestational hypertension and preeclampsia. We know that individuals who respond and continue to do aerobic training have less rates of gestational diabetes. We know all of these things already. So when we put in a known benefit and then kind of add in resistance training, we can’t say with confidence that resistance training reduces our risk of gestational diabetes because we know that aerobic training does and aerobic training is in that multi-component program. So it’s a big issue right now that we don’t have a ton of research that’s on resistance training in isolation, because then we can’t isolate and say resistance training benefits X, Y, Z outcome, and aerobic training, there may be overlap, and they also do X, Y, and A, B, C, but without studies done in isolation, interventional studies done in isolation, we can’t really say that this is incurring some sort of benefit. The second thing about our current state of the literature is that the resistance training research is unbelievably underdosed. So I’m gonna make a comparison for you. So the evidence that we have right now around resistance training in those with congestive heart failure in their 70s and 80s is higher dosed than a lot of the resistance training literature in pregnancy. Let me say that again. A lot of our dosing for resistance training is higher in our older adults with frailty, multi-morbidity, and complexity than it is for our uncomplicated pregnancies. When I am looking at that research, that makes me sad, and it just shows how much we need to do. When there is a randomized control trial that comes out in 2024, and the aerobic dosing is 70 to 80% of heart rate reserve, which is a great intensity for the aerobic training, and the resistance training part of the exercise program is using a yellow Theraband, I see red and I start to rage. And so the dosing here is unbelievably poor, especially for somebody, right, who we are not thinking has low musculoskeletal reserve going into their pregnancy, right? In general, individuals are not having trouble with activities of daily living as soon as they find out they’re pregnant. And so we are going in almost with this assumption that individuals who are pregnant cannot have higher loading on their skeleton. And we’re worried about strain, but a strain is not happening on the body with a yellow TheraBand for a person who’s of reproductive age who is pregnant. Like that is not an appropriate dose. And so it’s concerning that there is not an appropriate dosage for our resistance training interventions, especially when it is dosed appropriately. the aerobic side. So this brings me to our next problem. is if resistance training isn’t dosed appropriately, if I am getting an individual who is pregnant with no complications to do a 16-week exercise program where the max amount that they are allowed to lift is two kilos or 4.4 pounds, and I wish I was lying about that prescription, can I realistically, as a provider and as a researcher in that space, say resistance training was the part of that exercise program that incurred the positive benefit? Right, going back to my first point about how when we have multi-component programs and there’s a known benefit for aerobic training, it’s hard to see the additive effect of resistance training. In combination with the fact that the resistance training prescription is not sufficient, what I would deem sufficient, to drive musculoskeletal adaptation or maintenance to prevent deconditioning in a pregnant individual. That creates a problem. It creates a problem and it creates all the downstream issues that we’re seeing where pregnant individuals are restricted, right? Like when our max is a yellow fare ban on a 2024 randomized control trial, that don’t lift more than 20, don’t lift more than 30 pounds. that’s gonna hold, you know, that’s not gonna get better because we don’t have any evidence to back us up, right? And so this is like a call to action around how we need to change some of our thought processes around the way that we are prescribing exercise for pregnant individuals, but we also need to push back on academia and be like, hey, like, this is not okay for this to be the state of our literature because I hate that I have to say this and my postdoctoral supervisor and I were having this conversation. Do we even have enough evidence in resistance training in pregnancy to truly be able to include it in our guidelines? And the answer is we don’t. Not really. We’re extrapolating from our general population literature and we’re saying, well, based on some of the preliminary literature we have right now, light toning exercises seem to be okay. Literally the term in a big conglomerate of our RCTs was saying that they did aerobic training and light toning for our resistance training interventions. That drives me. It drives me with just unbelievable amounts of passion about why it is so important for this clinician science bridge to happen. It is why I will not step away from literature and doing research because we just need to demand so much better. And so what does that mean going forward? we need more research in this area. And so that is where my postdoctoral work has really taken off. So when we are thinking about our literature base, when the state of the literature is a two pound dumbbell, and I’m saying, I want to do an RCT where women are deadlifting over a hundred pounds, you can imagine that that amount of gap can create issues with an IRB board or an ethics board saying, whoa, whoa, whoa, whoa, whoa. We don’t want to put mom and baby at risk. here’s what we need to do. And so because of that, we need to build layers of evidence. So if you guys remember from your schooling, right, we have our levels of evidence from level five, which kind of our clinical commentaries, our professionals who are doing this in practice, that when the evidence isn’t there to back us up, and then we go retrospective, prospective, RCT, and then systematic reviews and meta-analyses are kind of at the top of this evidence pyramid. And so when we are trying to build an area that does not have a ton of research to back us up, we need to start building levels of evidence. And that’s what I’m trying to do. And so this started with our cross-sectional survey. You’ve heard us talk about this on our podcast, this podcast in the past, where the first thing that we have to do is show that there are individuals who are heavy lifting during their pregnancy. And so the cross-sectional survey that was published last year was the first step in that process. say, hey, look, we put out a survey for a couple of weeks online. We got almost 700 women who had lifted heavy during their pregnancies to tell us about their experiences. Great. Look, there’s this need. They are very confused about what they’re allowed to do and what they’re not allowed to do. Like they’re getting advice, like don’t lift more than 20 pounds. Two, if you were doing it before, you can continue doing it now. Just don’t strain your body. And even the strain on the body is a little bit question marks because, you know, there’s so much that goes into it, et cetera. Right? It creates a situation where we recognize that there is a need because there is an absence of literature and there are people who need the answers to that. The next part is that we’re going to start doing retrospective data taking and so right now I have two research studies that are open for enrollment and I am going to beg all the clinicians who are listening to this if you have a person who fits these bills if you could please please please send them our studies because I hope that the first part of this podcast tells you that there is just so much we need to do. There is so much that we need to do in this area, and I need your help in order to do it. So our retrospective study is taking individuals who have given birth within the last year and tracked their exercise through a training app. So if that was Wattify, if that was an Excel spreadsheet, if that was, you know, pen and paper, whatever it may be. If you tracked your exercise during pregnancy, specifically your resistance training, and you gave birth in the last year, we want you in our research study. So what we’re going to do is we’re going to ask you a whole bunch of questions about your pregnancy, your labor and delivery, how you felt about it, all those types of things, and then we’re going to ask you to upload your training logs. And so what we’re gonna try and do is descriptively see how did people modify? Are there any issues with resistance training that are popping up as patterns that clinicians or providers or obstetricians need to be aware of? And then how can we use that information to start help counseling individuals on strength training during pregnancy? And so that’s a retrospective study. We also have a prospective study that is open for analysis. This is gonna take me about three and a half years to get out, but that is okay. So we are taking individuals who are less than 20 weeks pregnant, so in that first trimester, first half of their pregnancy, and we are following them forward over time. So every trimester, we are asking individuals questions about exercise during pregnancy, and we are asking you to upload your training logs. And so what that’s going to do is it’s going to build on our level of evidence, right? So now we have cross-sectional snapshots in time. There are recall biases that happen with that. We have our retrospective study that because we were using the training log, that recall bias is worked around because we have evidence of what they did over time. And then the prospective study, we are getting their thoughts in real time going forward. And so now we’ve gone from a level five of evidence and we’re going to be pushing up to level With that evidence, my next goal is something interventional. Right now, we’re going to have this building of evidence that we’re seeing that is going to allow me to apply for funding for a randomized control trial that looks at different dosing schemas for individuals who are deciding that they want a resistance train during their pregnancy.

And so if you have any individuals or if you are listening and you are in one of these two camps, I would love for you to join our army to try and build the level of evidence on resistance training in pregnancy. It is so necessary. It is so needed. And we are going to be leading the way in our pelvic division. We are very actively involved in research. Obviously, I’m a postdoctoral research fellow, so I’m there in the weeds of it, but also our other faculty are involved in the trenches as well. And it’s just so, so, so important that we do this the right way and that we gradually build a level of evidence. And I am not okay with where we are right now. We need to do better. I will be part of the trying to make this better. And I’m recruiting you all to my cause to try and help me out. So I will post these research links in the captions, or you can head over to my Instagram at drchristina underscore private, and you can hopefully sign up for some of our studies. All right, if you are wanting to hear me get all fired up about other stuff or you wanna hear some of our faculty on the road, we have two courses in July that are still open for participation if individuals wanna sign up. I am in Cincinnati, Ohio. That is a smaller course. So if you are interested, July 2021, I’m in Cincinnati, Ohio. If you are interested and you are closer to Wyoming, we have a course July 27th, 28th in Wyoming. If you cannot get on the road because of kiddos like me who is coming early because kiddos are home for the summer, we have our next online cohort starting July 6th. So we are past 90% sold out for that course. So if you are looking to get in, please don’t wait because there may not be the opportunity and then you’ll have to wait until the fall. All right, that’s all I got. 19 minutes. I’m sorry, I just get so passionate talking about resistance training in pregnancy. I hope you all have a wonderful week, and we’ll talk to you all soon.

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