Jimmy: Welcome to the Physio Insights podcast presented by Runeasi. I'll be your host, doctor Jimmy Picard. I'm a physical therapist, running coach, and team member here at Runeasi. On this show, we have real conversations with leading experts digging into how we recover from injuries, train smarter, and use data to better guide care. Whether you're a clinician, coach or an athlete, we're here to explore what really matters in rehab and performance.

Let's dive in.

Jimmy: Alright, Kristen. Welcome to the Physio Insights podcast. Great to have you.

Kristen: Hi. Thanks so much for having me.

Jimmy: Of course. Yeah. So real quick, just to introduce you. You have quite the resume. So I'm gonna list off a couple things, but there's many more.

You're the Boston Marathon co medical director, assistant professor at Harvard Medical School, sports medicine physician with Boston Children's, and you practice what you preach. You're seven times Boston Marathon qualifier. Is all that correct?

Kristen: That's all correct. Yes.

Jimmy: Yeah. Pretty awesome. Yeah. It's cool to see a doc that's out there kind of doing these things and then working with runners too.

Kristen: It makes the whole kind of thing a lot more fun working in clinic with runners and then being out there on the roads as well.

Jimmy: Awesome. Yeah. So are you still training and competing?

Kristen: Yeah. Good question. So Boston Marathon used to be the my sort of annual thing. And I have not run Boston since I started working medical there. Volunteering clinically starting 2013 and then onward, I happen to run Boston since.

But I'm usually just competing, participating in local, you know, small stuff five k's here and there and just really kind of digging into staffing and covering a lot of the local major road races.

Jimmy: Very cool. Awesome. So, yeah, you sound like you're quite busy and can't be the co medical director and compete, I guess.

Kristen: They won't let you. My predecessor, Pierre Demcourt, who passed the baton to me for this role, if there was a way to do that, he would have done it.

Jimmy: Nice.

Kristen: But I think it's fraught upon. So we're at the finish line.

Jimmy: There

Kristen: you But I love that side of the coin as well.

Jimmy: As we get started, why don't you tell because I don't know this too, but, yeah, tell me a little bit about how you got into doing everything that you're doing.

Kristen: Sure. So grew up participating in sports, a bunch of different field sports, field hockey, lacrosse, got into track, and found I had a little bit of a for that with middle distance and had some success there through high school. In college, I joined the University of Notre Dame club running team, which is actually how I caught the bug with marathon running. So I started running Chicago marathon during college when I was out in the Midwest. Unbeknownst to me, qualified for Boston at the Chicago marathon and said, oh, okay.

I'll I guess I'll go do that. So at the age of 20, I ran my first Boston marathon. It was the year that was in the middle of the nor'easter. Yeah. And yeah.

So one of the worst weather years of all time at Boston. So that was my first Boston and just fell in love with the Boston Marathon at that event. I, you know, ran it seven times thereafter, became a part of the BA Boston Athletic Association running club, which is kind of like a a recreational high training high level training group. So ran out a bunch of times with the the BAARC and just fell in love with the event. But really, I think what I learned was I fell in love with the event as an athlete, you know, pursuing this goal.

It's an amazing it's an amazing athletic pursuit. But really what I think I fell in love with was learning about the races, kind of the logistical massive scope of the marathon and how I refer to it as what's called the Boston Marathon Symphony Orchestra. So you have thousands and thousands and thousands of people and volunteers and moving parts that come together like clockwork for the past two hundred plus years on race day to make this tremendous event happen with, you know, nearly 30,000 runners and and close to 10,000 volunteers, including 1,800 medical volunteers each year. So I just like became totally obsessed with this like logistics orchestra that I was part of. So I think I became more and more interested.

I was in, you know, went through medical school. Everything I was always doing with my free time had to do with sports or running. I, you know, started a local youth running group after school program. I coached for girls on the run. I was always running Boston, you know, in between classes.

I decided to pursue sports medicine fellowship which I was in Boston for all my training. So that brought me to meet again my mentor Pierre Doncourt who was the Boston Marathon co medical director for almost thirty years and he took me under his wing. I was volunteering at the marathon every year and sort of just, you know, deeper and deeper into this sort of like niche specialty of race medicine and injured runners clinic. So clinical treatment of runners as well, which is sort of my day job week to week. And and then I had the opportunity to step into the co medical director role as doctor Demcourt sort of moved on to a mentorship mentoring role for the the organization.

And so we're excited to move forward and and developing lots of interesting programs at the marathon and support runners in all different ways.

Jimmy: That's incredible. It's awesome to hear you giving back to the community and it sounds like, yeah, you just dove full into, yeah, running. Everything's running.

Kristen: Everything is running.

Jimmy: Yeah. I love it. That's awesome. Feel like it's like a not uncommon. You get the bug and then like everything becomes running.

Kristen: And Totally.

Jimmy: One of the things that makes treating runners so difficult.

Kristen: Yes. This is very true.

Jimmy: The main reason I wanted to get you on the podcast was just hearing or seeing these there's a bunch of studies you put out just this past year 2020 were super interesting. The three that I wanted to talk about first was looking at your two studies that you did with Boston Marathon

Kristen: Mhmm.

Jimmy: Which were pretty unique. I'll have you kinda talk to us about how and why you wanted to set up this kind of very unique questionnaire based studies looking at training parameters as well as low energy availability. And then the last study looking at biomechanics and then femoral neck stress fracture. So we'll start with these two that kind of focus on the Boston Marathon. So can you tell us a little bit about what you did there?

Kristen: Yeah. Absolutely. I think I'll just sort of globally set the stage and talk about the impetus for the study, how we put the study together, and then spin off and we can talk a little bit about the kind of findings of each separate paper and analysis. So the study that we put together which was sort of a novel research study approach, was in back in 2022 where we actually were trying to do the study before COVID and then COVID happened and, you know, the Boston Marathon was virtual one year and then it was rescheduled to an October marathon in 2021. So we sat on this idea for, like, through COVID.

And then finally in 2022, we were able to actually move forward with this study. So this study was performed by a group of international collaborators, leaders in sports medicine, physiology, nutrition, really wonderful group and with close collaboration with the Boston Marathon Medical Program leadership and support from the Boston Athletic Association, the Race Host organization, and it's sort of the secret sauce that made this all possible. So in 2022, what we did was in in collaborating with the BAA, we put together a a recruitment strategy where we recruited Boston Marathon registrants through email blasts sent out by the BAA communications team, recruiting athletes to enroll in our study and complete a fifteen minute questionnaire on REDCap. You know, all a very secure platform, also ultimately be de identified and answered a battery of questions that hit on a few different factors. One was, you know, their training and performance history, questions with a fair degree of granularity about their training and preparation for that year's Boston Marathon, as well as, you know, factors related to their nutrition, factors related to their medical health, and then factors, a number of items on the questionnaire that were related to, you know, validated markers of low energy availability, which we call low energy availability indicators.

And the athletes consented to participate in the study, completed those questionnaires, and then provided us with their bib numbers that allowed us to link and to pull the electronically available data from the race day itself, including time chip data with all of their five k incremental times and their final finish times and sex based and age based group rankings, division rankings. And then also, we were able to pull the it was called medical tracking data. The Boston Marathon is very special because we have one of the most sophisticated medical programs on the planet for a a large marathon event and has really been a leader in the the size, scope, and complexity of the the program. And part of that includes a novel electronic medical tracking program. So whereas historically, some of the medical treatment that goes on on race day, which on average includes like three to five percent of race populations, which is can be, you know, at these big races can be thousands of people.

So historically, it's all been on paper charts, paper records, and really tough to to from a research standpoint, to use paper records. Whereas the Boston Marathon, we recently started using a electronic tracking system where we have iPads at all of our 30 medical stations so we can check runners in and out for not only for research purposes, but but moreover, more the key there is using that for race operations planning, staffing allocations and, you know, medical staffing allocations as well as family reunification, letting these people people's families know where they are if they end up in a medical den. So we have this electronic medical tracking data. Anyway, so then we were able to pull the time chip data, the medical tracking data correlate or associate it with their pre race answers to questions and get some really interesting findings and findings that we felt were important for the general running community. And that is sort of how our, you know, two big papers that came out this past year were born.

We had over a thousand participants in the study, slight majority of women. So over 500 women participating in the study and nearly 500 men. And we're able to because of the support from the Boston Athletic Association in the recruitment, were able to put together what was one of the largest data sets put forth from a marathon in history and that gave us the power to look at some really interesting questions. The first paper looked at training load in preparation for the marathon and how training behaviors linked to race day outcomes.

Jimmy: Before you tell the results here, you had like a huge system in place to make this possible first off. It's like Mhmm. You were able to leverage that to get this huge sample of patients that are they say like runners and get a ton of information on them that would be really hard to get if this wasn't like set up so smoothly with the race organization. Totally. Is that common with races?

Like are other races doing things like are they disorganized?

Kristen: So no. It's really unique I think in term. This was a really unique undertaking because of the kind of partnership that we were able to develop here and the the yield we were able to have as a result. It's not common to have this sort of like tie in and support from a resource organization. And it is really kind of an area where the Boston Marathon is leading the way and setting an example, one that I hope other race organizations and other running researchers will adopt.

That you can do this kind of thing by talking to people, getting the appropriate institutional approvals, IRB approvals out front, you know, and being very clear in terms of, you know, research parameters and doing things all in the right way, but getting the right people at the table to work together. These types of things are possible. So it's interesting because we performed this study in 2022. It happened to be that, you know, me working here in Boston, you know, was able to collaborate with the right people to make this happen. But this study actually inspired something I'm very excited about, which was in 2023, the following year and going forward was the creation of what's called the official Boston Marathon Medical Research Program.

So now, this did not exist in 2022. It's just sort of, you know, we're just made things up from scratch and and did did as best we could. 2023 and going forward, and this is sort of an advertisement for all the running researchers interested, there is now a formal great medical Boston Marathon Medical Research Program where it is a standardized process where researchers that are interested from all over the country, all over the world can put together brief protocol description and submit an application, you know, by a certain annual date, usually towards the end of the summer. And it is submitted by and reviewed by a review committee that includes medical program leadership, BAA leadership, and one or two medical research protocols or sports performance research protocols are selected every year and receive one can receive 25,000 funding for the project. And then most importantly is all of the logistics support to get it done on race day with the Boston Marathon group.

So that includes, like, communications and recruitment ahead of the race or, you know, if you need time chip data correlation or all these different things, you know, we help facilitate it, you know, from the logistics standpoint, which I think is worth its weight in gold. And then you get the $25,000. So now we do that every year and I think it I'm so psyched to have this kind of infrastructure and support for other people that are interested too so that we can make this kind of more of a standard and and then kind of like expand what can be done in running running medical research.

Jimmy: Yeah. That's incredible. Was I trying to think like as you're talking of other races, know I I think in the trail running world, Western States will have some

Kristen: I think so. I think that maybe the that's the only other one that I've heard of that has a similar program.

Jimmy: Yeah.

Kristen: If there are others out there, then I'd be so interested to learn and know about what they're doing. But I know the Western States does have a I'm similar

Jimmy: not sure it's quite as robust as what you described. But yeah, it's great that this is happening, that we're seeing this kind of this step taken in the running research world.

Kristen: Totally. And I think it makes sense, right? Because as a runner, you're registered for the race, you're a captive audience, you know, reviewing those race host organization emails, and you're excited about an event, you know, everyone who is signed up for the Boston Marathon or whatever marathon you're you have on your calendar or like, you know, you're you're excited to be a part of it. And so a lot of people don't mind participating in a research study or or answering a few survey questions because I think everyone gets gets the importance of answering some of these questions and it's kind of neat to be a part of. So I think it just makes sense to like leverage this type of study structure more.

Jimmy: Yeah. And it seems like with at least with these two studies that we're about to discuss, you prove that like there's interest and that there that the participants are willing to participate.

Kristen: Yeah, totally. And I think like we we've, you know, fed back and trying to feedback more and more to the running community to give people some of these like tips and pointers of how they can support their performance and have a great race day by kind of like sharing some of that information.

Jimmy: Awesome. Yeah. So great segue to say like that first study where you so through that questionnaire you ask specific questions regarding training volume, training frequency, training days, like a lot of training parameters. And then you use that data to that and combine it with their performance outcomes of the rates. And yeah, share with us share with us what you found.

Kristen: You know, some of our our findings were not particularly surprising and but kind of reinforced a few kind of like key basic parameters and fundamental. So first of all, we found that in the year pre race, higher running distance per week, number of running sessions a week, number of quality sessions, and average distance, and more cross training was associated with faster times and performance. And this is all, of course, when we match by age and we match by gender. And then the interesting part here was that we found that with that said, the people who had higher training base foundation for the year ahead of the marathon, but had what we call a training frequency change. So they decreased the running the number of running sessions per week with at the four month mark before their marathon.

They were more likely to to run faster times. That was the best training strategy when you had a very high base, but then had a relative decrease in your number of running sessions a week. So the it basically put forth this concept that more is not always better, you know, relatively allowing for this sort training cycle and a relative reduction in your total training load in the four months before the race would would help you perform better. And I think it's

Jimmy: Normally when people are like scrambling to increase their training.

Kristen: Exactly. I mean every time I train, I just like, you know, you peak three or four weeks before and then you like have a little taper. That's always what I was taught, you know. And so it's really interesting to say like, okay, have a great base, but then you'll decrease your total load in the the four months before the race.

Jimmy: So you so just to be clear, high total annual volume and then Mhmm. Four months out from the marathon, there's a decrease in frequency of training. Is there also a decrease in volume of running? Is that what you're saying too?

Kristen: Correct. And that's that's the best sort of recipe by intra individual. So you wanna decrease your sort of relative quantity. If you reduced, then you would perform better.

Jimmy: Interesting. Like with your personal training, when you look at that, does it make you change how you think about your training or how you see athletes or injured runners?

Kristen: Absolutely. I think so I see injured runners all the time and I think that part of a lot of what I do that runners need is like support and coping with training through injuries and how they manage load. And I think that it is really interesting and helpful to have some data to support this concept that more is not always better and some relative reductions can actually do a body good and can actually be strategic. So I think it can help in some ways in reassuring people who who might need to reduce their load because of injuries or sideline because of injury about about reducing total load. But it is something that I've kind of taken into account in my own training and that we're trying to share the word with.

You know, we had this published in Runner's World and then a few different outlets and stuff. We're trying to get the word out that we don't just want people to, increase, increase, increase because there's risk for, you know, potentially it potentially can reduce your performance and in my kind of little clinical niche, I always think about total load and injury risk.

Jimmy: I'd like to take a moment to thank our sponsor, Runeasi. Runeasi is a running and jumping analysis tool that helps provide objective data on things like impact loading, dynamic stability and symmetry. I've been using it in the clinic for the past three years and I love how easy it is to add to my evaluations. Not only that, but it backs up my clinical reasoning and helps me with my decision making process when I'm doing exercise prescription. So if you're a physical therapist or running coach, head on over to Runeasi.ai, book a demo.

If you're lucky, it will be with me.

Jimmy: Off air, we talked about so I coach runners as well as treat and working with a runner I feel like you get this I get this a lot where it's like volume, volume, volume. There's this that big push for like more is always going to be better. Yeah. I even had with this one runner like cite an article that showed, yeah, increased training volume increases performance, but not to the details that we're talking here. We're like, hey.

There's a maybe it's valuable to have this deload coming up so we're not doing this this high volume all the time. Another side of the coin, also, worked with the runner, coached him I've coached him for a handful of years, and this year, he ran his lowest total training volume ever. So typically above 2,000 miles per year. This year ran 1,700 and PR ed in every event.

Kristen: Yeah. There you go. It's so interesting. Yeah. And that's the other point I think is really interesting from this study I don't think I highlighted before was that people who had more cross training

Jimmy: Yeah.

Kristen: In the four months pre race. So non running cardiovascular exercise was associated with faster times in performance. So the cross training. And And I think it's really interesting, like, managing load. Like, I listen a little bit to, like, what Parker Valby comments on and I you know, she has an interesting strategy.

I think she does a lot of, different types of cross training. And I think there's some might be something to to these types of load management strategies or kind of utilizing cross training.

Jimmy: Interesting. And yeah, with that stat there, this was cardiovascular specific. So aerobic cross training, not string training or something. Yeah. So more is not always better.

And so yeah, when you're in the clinic, this you're able to now have this as like a something to point to and say, hey, like Mhmm. Let's not scramble to do this. Let's not overdo it at the end.

Kristen: Totally.

Jimmy: Yeah. That's it is kind of mind blowing because I think like like we said, so many people are starting four week four months out with like Yeah. Yeah. Yeah. But it makes sense.

It's like, yeah, have this big base. I think have this big base and then fine tune it towards the end.

Kristen: So true. I wish I knew this when I was 20.

Jimmy: I think when I first read this study though, I misread it as like four weeks post Yeah. Of a pre. Yep. And I was like, oh, yeah. Of course.

That makes a ton of sense. Yeah. But this is four months.

Kristen: Four months.

Jimmy: Yeah. Really really interesting.

Kristen: It's really yeah. It's a dense study. There's some interesting stuff there. You know, it's a lot of nitty gritty, but I think it's really interesting to see what's possible in in looking at some of these numbers and the output from, you know, looking at their race day times.

Jimmy: Yeah. Very cool. Yeah. And congrats on getting that put in the runner's world too. That's awesome.

Thanks. Yeah. Yeah. Thank you. So then if we moving forward, the next study where you had was the low energy availability indicators.

Yeah. This one was probably like the most shocking at least to me and I think this is how I heard about you was seeing this study quoted on social media with a prevalence as high as forty percent in female runners of the Boston Marathon.

Kristen: Yeah. So thanks so much. I and this was a really really kind of big focus for our research group and I and we thought it to be we think it's a really important component of the piece in the puzzle of the information about energy availability in, in athletes because it was one of the first ones to really tie energy availability markers to running performance.

Jimmy: Mhmm.

Kristen: So with this study and with this analysis, so same study group, we had over a thousand runners participate again, you know, 546 female, 484 male. And the majority, I think around 70% were Boston qualifiers or so, 30% were, you know, registrants by charity charity teams, which is a wonderful program we have at Boston. And basically, what we did with this was we screened, we used that pre race questionnaire to screen for indirect markers of what's called low energy availability. So low energy availability is problematic chronic imbalance between how much energy we're expending during our sport related activities plus our daily lives and metabolic functions, and then how much total calories we take in and types of nutrition. So there's an imbalance there.

And it can lead to what's called relative energy deficiency in sport which is a host of health consequences and we're starting to learn about some performance related consequences tied to this low energy availability status. So you can there's been a mountain of foundational literature that has tied certain questionnaire questions and certain clinical signs and symptoms to validated measured low energy availability. So because of that foundational research, we were able to use validated questions in our questionnaire to screen for individuals who likely have low problematic low energy availability. Yes. So we ask things like for females, it's it's, the best the common marker is menstrual dysfunction, losing periods, or much lighter or infrequent periods while you're training.

In males, there's, some questions regarding libido changes linked with low energy availability. There's screening for diagnosed eating disorders or disordered eating behaviors. And those are really kind of our key tools to to identify this type of thing. There are certain questionnaires that have been used. So we used, for example, the LEAF Q, low energy availability in females questionnaire or the EDE Q, which has been highly utilized in different research studies.

We use that. So then okay. So we use those to screen. And first of all, we found that forty percent over forty percent of the females we screened had markers of low energy availability and eighteen percent of the males we screened had markers of low energy availability. And then we went forth to tie to look at association between low energy availability indicators and race day performance times.

And so we found that for both males and females compared to their age and gender matched counterparts, those with low energy availability performed at much slower times on race day compared to their their counterparts that did not have markers of low energy ability and energy ability. So they're quote unquote healthy counterparts. Right? So you're more likely to have slower times if you had these if you were under fueled. And moreover, we also saw, I think, two kind of key findings where you were those with low energy availability indicators were more likely to have raised a medical encounters through our medical electronic medical tracking system.

We were able to get data output to see who showed up in the medical tents and folks with low energy availability were more likely to need medical support. And so they were twice as likely to need medical support on race day and three times more likely than their healthy counterparts to have a serious medical encounter. So a medical encounter that resulted in a hospital transport, DNF not finishing the race or like a serious medical presentation.

Jimmy: Yikes. So decrease in performance, increase injury or like use of medical. So like, yeah, serious injury. Yeah. That's no good.

Kristen: No. It's not good. And then we I think we also found much higher risk for bone stress injuries pre race. So in those with low energy availability. So there was a a pre race issues as well and and there was a significant difference in likelihood of not be not starting the race among those with low energy abilities.

Jimmy: Yeah. Remind me, when did the initial questionnaire go out to them?

Kristen: About four weeks pre race.

Jimmy: Four weeks. Okay. Wow.

Kristen: So Yeah.

Jimmy: With the questionnaire, were you using the full like LEAM Q, LEAF Q and the other or were you pulling questions from those?

Kristen: Good questions. So we used the full LEAF Q and we did some important secondary interpretation for the Leaf Q that is shown to be important. So excluding people who are on like hormonal OCPs or like hormonal IUDs, recent pregnancy, women who are postmenopausal, we weren't able to interpret the LEAF Q menstrual function section in those groups, but we looked at the other parts of the LEAF Q. For the LEAF Q, we only utilize the reproductive function section because that's the best validated LIEM Q section from the kind of early studies. So we were really fortunate.

This group of international experts I mentioned as co authors on the study were involved in the development of the LIEM Q. So we sort of had really, really great people at the table who were able to guide the selection of how are we gonna interpret this stuff and what's a good what's a, you know, good marker to utilize. And so we that helped really zero in on the reproductive functions for the for the males. So we did as best as we could in identifying low energy availability in in males, which remains a challenge to screen.

Jimmy: Yeah. Personally, like clinically, it's always like a tough one. Like, when I see it Yeah. Yeah. I suspect low energy availability in a male runner and the questions I are have a question.

I have some questions on my intake form to try to help. So I guess based on what you found here, one, it's like pretty shocking that the prevalence was that high. Like when you saw that, what were your initial impressions?

Kristen: I wasn't that surprised, to be honest. Unfortunately, yes. Yeah.

Jimmy: Right? We

Kristen: see so many we see so many just because I see you know, I'm so biased because I see the folks who who come into my clinic, you know, Monday through Friday with, with injuries. So we see a lot of folks who are struggling with low energy availability.

Jimmy: Yeah.

Kristen: But you you're right. It was eye opening that this was a screening questionnaire that was applied in a healthy runner population.

Jimmy: Yeah.

Kristen: Oh, and this was not my day to day, you know, folks who are coming for help with through injuries in clinic. This was a healthy, quote unquote, healthy just in the world runner population, and and forty percent of of those women in that group were having low energy availability indicators. I think the other interesting thing that came from this was one is highlighting that a very large percentage of these individuals had no diagnosis of disordered eating behaviors or eating disorder features. Their EDEQs were super low, but they still had some markers that they like. They had physiologic low and problematic low energy availability.

And I think that really highlights the need to open our eyes to this very large population of athletes who have what's called unintentional low energy availability. Yeah. So there's a lot of factors in athletes that can play into unintentional lower energy availability. Of course, there's, hey, low nutrition knowledge. Maybe not don't know about the right fueling or what you need to fuel for marathon training.

But then there's also other factors. There's exercise related appetite suppression.

Jimmy: That's fine. I was talking to my wife about this morning. Yeah. I swear I'm I'm like randomly training for a two k row event.

Kristen: Yeah. Cool.

Jimmy: New thing for me and I did like a tempo session this morning and I finished it and I was like going up to have breakfast. I was like, I cannot eat. And I was like forcing myself to eat because I'm I'm like at least aware of this.

Kristen: Totally. Yeah.

Jimmy: Yeah. The appetite suppression is real and if you're not aware or like you just say like, oh, I'm just not hungry. I'm just going about my day. Like, you

Kristen: Yeah.

Jimmy: Do that a couple times a week. Yeah.

Kristen: Totally. So you have to have a plan. Right? And you you can't just rely on your appetite because, you know, it it seems like such a cruel trick of nature that you would have exercise related appetite suppression. Like, what's with that?

Jimmy: Makes sense.

Kristen: That you should be hungry as a horse, but that's not always the case. So I think having a plan for your nutrition and your fueling to offset your caloric spend is really important. And, you know, that's really key. And then I think there's issues with, some athletes having relatively lower energy dense diets too. So the types of foods they're taking in are ideal.

And so I think that's really important. I think the other important thing that I wanted to highlight here is our study also showed that there was no correlation between calculated BMI, so athlete height and weight, with their likelihood of having low energy availability indicators. So, yes, it was so important when we're seeing our athletes in our clinical settings that, you know, just because someone Doesn't doesn't doesn't look skinny or doesn't, you know, looks health quote unquote looks healthy, whatever that means. You know, athletes can be so lean and so low body fat and high muscle that a lot of athletes may be actually, like, low energy availability, but not quote unquote look that way, whatever that means. You know?

And I think that's a big wake up call to all of us as clinicians to be talking about these things in every athlete no matter how they look and screening for these things. And then the other thing is there was no correlation between calculated BMI, so calculated height and weight, and performance outcomes. So low energy availability was tied to performance outcomes in making them worse, but, like, having a lower BMI was not tied to running any faster. It didn't matter your BMI. I think this sort of tagline that we sort of brought out of this study was this sort of, you know, lighter is not always faster.

I think there's been this sort of, like, thought that quote unquote lighter is faster, in runners based on kind of a basic physics equation, you know, with with weight and power output. But it doesn't necessarily add up in a human being who has muscles that you have to fuel, who has bones that are at risk for bone stress injuries, who has mental health factors that that factor into their race performance and low energy can affect. So I think just showing that lighter is not always faster was a big kind of takeaway for us.

Jimmy: And so I I guess I'm going back to like this high percentage of like you said healthy, not people showing up to our clinic. Right. It's kinda scary because then it makes you it does make you wonder, yeah, then what percentage of our injured athletes are fitting Right. Like coming to us like this. Yeah.

Briefly, we talked off air like about when a runner presents to us in the clinic, if we're not screening for this or we're not paying attention to this, are we like fighting an uphill battle trying to get that person healthy?

Kristen: Yeah. I do think so. I do think that screening for low energy availability indicators through some a few basic questions can really help identify someone's energy availability status. And I think energy availability is really playing into athlete performance and athlete response to neuromuscular skeletal training and and physical therapy training and rehab. This study sort of inspired a a later project we did, which was a systematic review that was just published in BJSM where we looked at adults who were exposed to low energy availability in controlled settings and put through a neuromuscular skeletal training program, a physical training program.

And we found 21 high quality studies that had looked at this specific question and all the pooled results basically showed the vast majority of them demonstrated that people who are low energy availability, they're under fueled no matter how much you're physically training them or putting them through, you know, reps and exercises. They actually had either individuals with low energy ability had either no response physical training, so they had no increase in muscle mass

Jimmy: Wow.

Kristen: Or they actually had losses. Same with v o two max. So their v o two max measures got worse in response to their physical training sessions. Their their muscle protein content, glycogen content, everything either plateaued or declined in response to physical training. So I think it's so important to get just, like, educate educate athletes who are coming back to from injury, who are trying to rehabilitate, who are trying to run their best, or, you know, have a great day at a marathon or get back to running that they need to fuel.

Jimmy: It's hard because all I'm thinking about now like those people who take up things like running where maybe they're not grossly overweight or anything like that, but they're coming to running and running a marathon with the idea of losing weight and getting healthier. Yep. And then Yeah. It seems like this is a tricky thing to balance now.

Kristen: Totally. I think that there is there's I think that folks who have certain weight loss goals have act who have actual, like, markers of obesity or overweight with higher body fat content should really work with their physicians and with likely a a sports dietitian to kind of develop a healthy strategy, and how they will, you know, try and lose fat while training really well and staying healthy. You know, for some people, weight loss is an important part of their kind of lifelong health. And so I don't mean to kinda exclude that group. I think for a lot of athletes in the long standing endurance running community, they're likely many of them are sort of within normal body composition parameters.

And so there are certain, like, sport related myths that link to, like, quote unquote lighter is faster. You know, you take a healthy young woman, you know, who has a BMI of twenty twenty one and you tell her to lose five pounds for for no logical reason other than, you know, that that's a sport myth. You know, that's the kind of thing that we're trying to debunk.

Jimmy: And I think, like, I'm sure you've read it, but, Lauren Fleishman's book, Good

Kristen: Times for Oral

Jimmy: B, like, opens up about all that stuff is

Kristen: Totally.

Jimmy: Great. And I have two copies on my shelf, so I give them the patience Yeah. Have me have

Kristen: That's awesome. That's great. Yeah. And, you know, Mary Kayne's story and all these things. We're So just trying to, like, to flip the narrative around, like, this I I say all the time, to patients that are struggling with RUDs, but, like, the the only number that matters is the number on the clock.

Right? Is there is the time on your clock, on your watch, or on that race clock. The number on the scale doesn't matter. Right? Like why has there been such a focus in sport culture on that weight number when it doesn't actually make any logical sense?

So we're really getting yeah.

Jimmy: I guess it's it's a slippery slope because I remember when I was in college training, like, at the d one level, like, I def I slipped into this, like, probably, I would call it disordered eating for a bit and ended up with a sacral stress fracture as a result. But I didn't think I was doing anything wrong. You know, it was like it seemed like the right thing to do. I had yeah. And then it was in the on the team, I remember we had fortunately, we had a our this is at William and Mary, and there's a woman on the girls team who it was clearly under eating, it was getting sick and she was the top performer, but the coaching staff was like good enough to intervene and stop her from competing.

Yeah.

Kristen: Yeah. And we see that sometimes and, you know, it can be I think we can see people that are all all different kind of arcs in their sport performance trajectory and their individual relationships with their kind of body image and their energy balance. And we sort of think every individual has intrinsic protective factors and intrinsic risk factors for incurring injury or performance changes. So everyone's a little bit different. But I we tend to think in this sort of like clinical world where where we live is that sometimes these things can start to catch up to you if and when they start to like problematic low energy availability which is sustained or severe low energy availability can start to affect your metabolic function, your bone health, your muscle recovery.

So we think sometimes people can like go along with it for a bit, but then ultimately it may catch up with folks. But everyone's a little bit different.

Jimmy: Lauren's book talks about this, but it's like if the longevity is the goal and you wanna stay competing for a long time, is it worth it for that short term results of like maybe you do have success for a little bit, but then you're Yeah. Chronically injured afterwards as a result. Totally. Yes. So I guess we're we're kind of making our way towards like stress fracture talk and things like that.

Typically, we see that associated with low energy availability or problematic low energy availability. We also have a pretty interesting study looking at biomechanical changes post femoral neck stress fracture. And it was that in females only that study?

Kristen: It was in females only. Yes.

Jimmy: Can you tell us about that one?

Kristen: Yeah. So we're always sort of thinking of, like, holistic care for the athletes. And in all of this, we think a lot about like, we've talked chat about, we think about training load, we think about recovery, we think about energy availability, and then we think about get to think about biomechanics which is such a fun part of the job. And so in this study, this was a retrospective case control analysis if you will, where we were compare we compared, 18 female athletes who had history of a femoral neck bone stress injury and compare them to 18 age matched female athletes who had no history of a femoral neck bone stress injury. And we looked at their running gait biomechanics and their a few strength measures and compared and we sort of saw where were their differences in some of their biomechanics.

Most of the running gait biomechanics analyses were performed about ninety days after the diagnosis of a femme neck bone stress injury. So most were somewhere in their kind of like return to run, very gradual return to run plan and had been cleared for impact. So we saw some interesting, findings in in the women who had been diagnosed with feminine bone stress injury. And it was sort of a cluster of what I'll call like coronal plane gay biomechanics factors. So one was so first of all, they had greater pelvic drop when their historically injured limb was on the weight bearing side.

They had with and that was paired with valgus knee displacement, medial knee displacement, as well as midline crossover of the foot and ankle and then rapid pronation at midstand. So this sort of like kinetic chain collapse in the coronal plane which one might envision. We we didn't directly study in in this research study, but one might envision could create residual strain on the femoral neck. Yeah. And then with that, we saw these folks had some residual hip abductor strength deficits in comparison to their healthy counterparts.

Yeah. I think it's interesting in the post injury time point because it shows where these where like some of these residual patterns and biomechanics and strength deficits can likely be very very important for athletes and their rehabilitation teams to to work to correct over time either through targeted strengthening or gait retraining. And it was just sort of an interesting way to to look at some of the biomechanics elements Yeah. In play with a common running related bone stress injury.

Jimmy: Did you did you guys look at the uninjured leg as well? Did that like Yes. So on that side either?

Kristen: Oh, good question. Okay. So these were fairly symmetric side to side. So so which kind of bring I don't know. In my mind, I think it kind this is a little bit of a chicken and egg.

Right? This was the limitations of this study was clearly was cross sectional as post injury. That's how we identified our case group. This was not prospective. But it brings I think there's a little bit of a chicken and the egg in my mind here that some of these gait patterns may have been like habitual and it could have played into injury risk.

I'll never I wouldn't be able to prove that unless we redo this in a prospective way, but there was some of these elements seen on both sides.

Jimmy: Interesting. Yeah. So it makes you yeah. At least like question, yeah, what did this look like beforehand?

Kristen: Exactly.

Jimmy: I guess clinically, this seems really relevant because like you said, this is right as this these runners are returning to run. They're working with you, they're working with me. We're trying to get them back to loading and we're still seeing alterations in yeah, gate mechanics.

Kristen: Totally.

Jimmy: Obviously, this this podcast response by RunAZ which is a a gate analysis assessment tool. Very cool. Honestly, personally, that's, like, one of the reasons that I use Runeasi is so that when I'm having these stress fracture patients return to run, I can show them, like, the data and not just, like, point to, like, a or, like, tell them this is what I'm seeing. I can show them data and say and I think you you work with instrumented treadmills in your clinic as well.

Kristen: Yeah. So I love that you guys use Runeasi and you're able to like teach back to patients using Runeasi. We have a Niraxone Force Plate treadmill with two d video capture in our injured runners clinic where we're seeing these patients. So we get them on the treadmill and just show them and it's a teaching tool, right? And it's a buy in.

It's it's to get buy in from people in their recovery plan.

Jimmy: Yeah. I just I keep I recently had a kid, a high school runner who I saw last year for an injury, got him back and at the end of his injury last year, we did a gait and assessment and I had all the data from that. And then I saw him recently for stress fracture. And then at this time frame like let's say it was a little bit earlier than ninety days, maybe it was like sixty something sixty days whatever. We're back starting a walk jog.

Kristen: And it was

Jimmy: awesome because I could show him his previous data.

Kristen: Oh yeah.

Jimmy: Now this is where you are right now.

Kristen: Yep.

Jimmy: And you know how these high school kids are when you give when they start their quote return to run, they're ready to just start running.

Kristen: Oh, yeah.

Jimmy: Yeah, you're having some sort of data where you can show them, hey, like this is where you were. You are nowhere near that. Yes. And your study kind of also is helping just like also have back it up with scientific data.

Kristen: Yeah. Exactly. I think it's just like highlighting the importance of some of these biomechanics factors and I think it's such a great way to get people to buy in to some of these rehab programs by showing them, you know, certain of these biomechanics quote unquote risk factors or you know associated gait parameters and and say, you know, this is why you need to strengthen your hip abductors or this is why you need to, you know, have a little bit wider step with like what whatever the case may be, I think it's really helpful to help people understand the nature of the injury so that they can help themselves.

Jimmy: Yeah. And then in your role like, yeah, working with an athlete or an injured runner in this condition and setting that you described. So when you get that information from your your fancy, super fancy treadmill, Are you then yeah, how are you are you sharing that with the physical therapist? What do you how does that work your relationship with like rehab?

Kristen: We work closely with our physical therapy referrals. So we do have some in house physical therapy professionals at Boston Children's, but we work with a ton of community physical therapy teams. And so what we'll do is share the running gait reports with the therapy with the patient's physical therapy provider. And I always put together a written summary of the kind of key factors that I've seen and then practical ways that I think we can work on them from like usually, it's for most of these people, it's like it's just strength and range of motion elements that I think just translate into some gait parameters. You know, maybe there's some neuromuscular or like gait pattern retraining here and there with some specific mental cues.

But usually, it's it's really focusing on certain muscle groups and it allows kind of like a in a bit more informed targeting of of their kind of PT programs and we've gotten good feedback from the physical therapy groups that, you know, have we've sort of partnered with in this way.

Jimmy: So two questions there. First one, what are your thoughts like do you have an opinion on gait queuing or trying to manipulate gait mechanics?

Kristen: I think think in light ways. So I think only if it's layered onto a foundation of the right preparation from the strength and range of motion standpoint. Then very very like minimal, I think mental cues can help people along their way. I am not personally the person who says, oh, you had a tibial stress fracture so now you need to be a forefoot striker because most people can't sustain that. At least a lot of my, you know, the 16 year old patients cannot, just from the kind of strength profile standpoint and coordination standpoint.

But anyway, so we I spend probably 80% of my teaching with patients talking about the strength and range of motion elements, which I do believe is kind of like their core risk issues and then provide a little bit of queuing with some tips on running form. Simple stuff. Like, I'm I'm talking like like reducing verticality, staying level headedly. I'm talking not too much cross body arm swing, you know, because you're over rotating. You know, like, I'm doing really subtle stuff and only if they're ready for it.

Jimmy: That's awesome. I think we're on the same page, guess. The other question piggybacking off of this, your your relationship with the physios or the PTs that you work with. As far as like collaboration goes or like, I'm just always curious like, what do you like from the physical therapist? Do you like them to be, like, sending you a note and updating you?

Like and what are your relationships like with the PTs?

Kristen: Yeah. Always really good. I think I so much appreciate a physical therapist insight because they have such a training background and a frequent interface with the patients that I always really value their observations, input, feedback, updates, whatever the case may be. I think it's a really, really wonderful relationship because, you know, you guys are actually out there treating the people and making them better. And so as much communication as possible.

Usually, we'll communicate by emails since I'm always on email. People will just ping me an email and they'll be like, I know, you know, Joe Bob is coming back in to see you in clinic tomorrow. Here's how he's been doing. Here's what you should look at. I've noticed this is going well.

I've noticed this is not going well because he's never doing his home program. Can you hammer this home? So we sort of like collaborate and I think that's really nice and such an awesome way to optimize outcomes for patients.

Jimmy: Yeah. I I agree. And I think it's like from the PT standpoint, sometimes it's intimidating for us, right? We like especially now, like I operate in a cash pay out of network model. Sure.

And so we, you know, the that model in a way separated you and I. Right? But I think I've like recently have been working really hard to form relationships with these sports med docs because like you said, if we can collaborate and we can have that ongoing communication, we're sending similar messages, the buy in is going to be better, the patient's going to get better quicker.

Kristen: Yeah, totally. And I and like it can go in so many ways. Like I just mentioned, there's all sorts of examples where I really appreciate the, like, kind of physical assessment feedback and and tips and updates. Also, I've had this links back to our reds conversation or our low EA conversation couple times recently. And, know, in my clinic, I'm sort of part of the female athlete program.

And so we're always screening for low energy availability like, you know, for example, asking women about menstrual function or, you know, younger girls about their eating behaviors and and menstrual function history. But I've had a couple times recently where a physical therapist has reached out and said, oh, hey. I'm working with little Susie here and she was in the room with her dad when you guys were sort of talking about some of this stuff. I'm I'm really worried about her. It sounds like she hasn't on her period now in six, seven weeks.

And can we maybe get her back in to, like, do some screening labs looking at low energy availability indicators? I'm like, oh, absolutely. Totally. You know, let's really kind of focus some of our time and our next follow-up appointment on this issue and, like, I'll get some labs. Maybe we'll get a DEXA or whatever is needed.

But, like, that kind of feedback just because, you know, in the physical therapy setting, guys have such an opportunity to see people so frequently and, like, develop those relationships. And sometimes people are patients are, you know, feeling more comfortable sharing in different environments or for whatever reason than others. But so like I'm having like some of that like feedback and it's been really helpful because then I can capture it the next time I see patients or, you know, call people to say like, hey, do wanna follow-up sooner? We should I wanna see how you're doing. And that's been really great.

Jimmy: That's awesome. Yeah. And it's Yeah. You're inspiring me to wanna like continue like, yeah, build this team around me. Yeah.

Because as a solo person out here, it's like, yeah, I can't you can't do it all. I need a dietitian in my corner. I need a sports, the med doc in the corner, know, we need all of us working together and communicating is

Kristen: Yeah.

Jimmy: Yeah. That's the way to go.

Kristen: Absolutely.

Jimmy: Wrapping things up, if you had advice for let's say like, I think most of our listeners are probably PT. So any advice based on kinda the whole conversation we just had? Any like key takeaways you'd really wanna make sure that they got from this talk?

Kristen: So I think the key takeaway here is gonna be screening for low energy availability in your athlete patients and keeping nutrition and energy balance on your radar as a key part of rehabilitation and sport performance goals. And just always know that the field is wide open for sport medical research, sport performance related research. So just kind of pursue your passions in that way answering answering interesting sports related questions and thanks so much for having me today.

Jimmy: Yeah. Awesome. And before you run, where if people wanna learn more about you, where should they go?

Kristen: That's a good question. Probably so folks can either shoot me an email or can follow me on Instagram is a great way. I'm always on both. So my Instagram is kristin with an I n k r I s t I n, whitney, w h I t n e y like Whitney Houston dot m d at oh shoot. I messed that up.

Can I say that again? Alright. So folks can either follow me on Instagram, or can always shoot me an email. My Instagram handle is kristin, k r I s t I n, whitney, w h I t n e y dot m d. And my email is same first name kristen.

Whitneychildrens with an s dot harvard dot edu but always happy to chat and collaborate.

Jimmy: Awesome. I'll put the links in the show note there too. Thank That was great. I really appreciate you taking the time to come on and really hope you have more cool studies coming out because it just makes us better clinicians and helps us educate our patients better. So great work, keep it coming.

Kristen: Awesome to talk to you Jimmy. Thanks so much.

Jimmy: Yep, take care.

Kristen: Take care, bye.

Jimmy: That's it for today on the Physio Insights podcast presented by Runeasi.

Jimmy: Would you like to share an interesting case, insight, or have a thought about the podcast? Comment below,

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