Ep 194: Teaching runners to RUNSAFE, with Dr Rasmus Nielsen

[00:00:04] Hello and welcome to JOSPT Insights, the podcast that aims to help you translate quality research

[00:00:10] to quality practice. I'm Claire Ardern, the editor-in-chief of the Journal of Orthopaedic

[00:00:15] and Sports Physical Therapy. It's great to have you listening today.

[00:00:22] Today's chat is all about running load and injuries. Dr Rasmus Nielsen brings the perfect

[00:00:28] combination of experience to today's podcast. As a physiotherapist, epidemiologist, former

[00:00:34] running shoe store employee and most importantly an avid runner, he's perfectly placed to update

[00:00:40] you on all things running related injuries. Rasmus is an associate professor in epidemiology

[00:00:46] at Ahus University in Denmark where he leads the Runsafe Research Group. Check out the

[00:00:52] show notes for links to some of the work that Runsafe has been doing over the past

[00:00:55] couple of years in the international world of running load and injury.

[00:01:00] Dr Rasmus Nielsen, welcome to JOSPT Insights.

[00:01:03] Thank you very much Claire. I'm happy to join.

[00:01:06] I'm very happy to have you on the podcast Rasmus. Today we're talking about running

[00:01:10] which is very popular. It's far more accessible as a physical activity than many

[00:01:15] other sports and it's got great physical and mental health benefits. So there's lots

[00:01:20] of good things about running. Unfortunately the downside is that runners also get injured

[00:01:24] and you've done a lot of work looking at running related injuries. So let me start by

[00:01:30] asking you how many runners sustain a running related injury?

[00:01:34] Too many unfortunately. We'd like the runners to stay active and gain the health benefits.

[00:01:41] But depending on how you define an injury, I would say around 24% of all runners sustain

[00:01:48] at least one running related injury per year. It could also be condensed into other

[00:01:53] metrics. For instance 17 injuries occur per thousand hours of running which can be

[00:01:59] transferred to if you have 100 runners that runs for 10 hours, 17 of the 100

[00:02:04] runners would sustain an injury. So the risk of injury is unfortunately quite severe.

[00:02:11] What are the most common types of running related injuries? What should people in

[00:02:15] regular practice listening to JOSPT Insights today expect to see in their clinic when

[00:02:21] they're working with runners?

[00:02:23] It's mainly injuries in the lower extremities. In particular we see the knee is a very

[00:02:29] commonly affected anatomical location followed by the ankle and in the knee

[00:02:34] we typically see patello femoral pain as the most frequent injury followed by

[00:02:40] runner's knee, jumper's knee also meniscal injuries and further distally we

[00:02:46] often see injuries to the Achilles tendon and also in the plantar pathiae.

[00:02:51] So there's a lot of injuries in the lower extremities which makes sense

[00:02:56] because running is weight bearing activities.

[00:02:58] It absolutely makes sense and it sounds like a mix of chronic or overuse type

[00:03:04] injuries as well as some of the acute type injuries like meniscus tears

[00:03:08] and we'll get into talking about why that might be and how to manage some

[00:03:12] of those load issues that might feed into some some overuse problems like

[00:03:18] tenenopathy. But let's first talk about what causes running related injuries

[00:03:23] and I alluded to load and overuse there so so expand on that for us a little bit

[00:03:27] please.

[00:03:28] Traditionally we have divided injuries into two categories. Those that were

[00:03:33] caused by overload which is a trauma you run and then you step into a hole

[00:03:38] and you get ankle distortion for instance and on the other hand we have

[00:03:42] the overuse injuries where you run too much too soon however defined then

[00:03:47] eventually will lead to an injury. So traditionally also in the clinical

[00:03:52] textbooks we have these two types of injuries. It is sudden development

[00:03:56] where the runners typically can say it happens right there I stepped into

[00:04:01] the hole and I really sustained the injury. On the other hand we have

[00:04:06] the overuse injuries where runners are much more hesitant or they don't know

[00:04:11] what actually happened. They just say oh the injury just occurred I don't

[00:04:14] really know why so that's a real traditional approach in the past few

[00:04:19] years actually a new domain has surfaced where we divide the overuse

[00:04:25] injuries into two different types other those that occurs rather

[00:04:29] subtly it's not stepping into a hole but maybe you're suddenly over one

[00:04:35] running session for instance if you run too much in a single running session

[00:04:40] then you could sustain an injury imagine Claire that you

[00:04:43] I used to running let's say 10 kilometers as your longest run and then

[00:04:47] you suddenly run 20 kilometers then the injury risk would be high

[00:04:51] just based on one running session where you run 20 kilometers.

[00:04:55] On the other hand there's also the gradual onset

[00:04:59] overuse injuries where you develop the injury over time maybe one to weeks

[00:05:05] where you gradually expose the body to a slightly higher load than usual which

[00:05:10] is over time too much and then also running a great well a cure there

[00:05:15] based on overuse and that's the new idea that that overuse injuries

[00:05:20] is not just something that is gradually occurring over time

[00:05:23] but it's occurring either at something that occurs rather suddenly

[00:05:28] versus those that occur over time and how does that new

[00:05:31] definition of overuse affect the way that we interpret previous research

[00:05:36] rasmus that's used different definitions of overuse and an acute injury

[00:05:41] well rather than just decontamination where we have two two domains

[00:05:45] overuse and overload injuries we have now three different categories

[00:05:49] where we have the overload as one which is has always been there but

[00:05:54] the overuse path or overuse definition has been divided into two either

[00:05:58] at the gradual onset injuries which is the normal way of looking at

[00:06:03] overuse injuries and then the new more subtle repetitive

[00:06:06] onset maybe during just one training session that that's a new

[00:06:11] idea that we look into which I think makes sense because a

[00:06:15] runner can sustain an injury just in one running session

[00:06:18] which is based on overuse so I think the new idea is

[00:06:21] it's highly appealing and interesting also from a training load perspective

[00:06:25] I want to pick up on training load in a second but before we get there

[00:06:29] I'd like to talk about this idea of cause and effect

[00:06:32] can we say that too much running or too much load

[00:06:36] directly causes running related injuries from a theoretical perspective yes

[00:06:42] so if we should sustain a running related injury we need to run

[00:06:49] so that's a prerequisite call it a necessary course so we have to run

[00:06:53] in order to sustain an injury then it's a matter of how much you run

[00:06:58] under which circumstances and using a certain type of equipment

[00:07:02] that is decisive of sustaining injury or not

[00:07:06] it's a matter of understanding how much running is acceptable for runners

[00:07:11] with different characteristics and for runners that use this

[00:07:14] different equipment so it sounds like we've got a pretty settled

[00:07:18] research field in that sense of cause and effect which is a nice

[00:07:21] place for us to start from the other debate discussion that's been going on

[00:07:27] for quite a while now in the Sports Medicine and Musculoskeletal

[00:07:30] Rehabilitation Community is this idea of the acute to chronic workload ratio

[00:07:34] this idea of having a consistent training base

[00:07:39] is to some degree protective of against injury and then if you go and

[00:07:43] spike the training load too quickly do too much too soon then you are either

[00:07:48] going to cause an injury or at the very least much increased the risk of injury

[00:07:53] can you tell us a little bit about where that field is at now how

[00:07:57] how are we thinking about acute chronic workload ratio

[00:08:00] well it's good thing that we as researchers have started considering load as a primary exposure

[00:08:08] interest in our studies and then look at shoes body mass index age other variables

[00:08:15] that can affect how much increase in load that a runner is able to tolerate

[00:08:19] but the question remains what exactly constitutes load and the rule of thumb

[00:08:25] used by runners which is 10 percent what exactly is the algorithm to define those 10

[00:08:32] percent and then the acute chronic workload ratio which was invented by

[00:08:36] by an Australian researchers Tim Gabbett and colleagues take the acute phase which is one week

[00:08:42] divided by what you have done in the preceding three weeks so traditionally in both in running

[00:08:48] injury research and also sports injury research in general we have used this

[00:08:53] so to say gradual approach where we have used what was described in the textbooks

[00:08:57] where overuse injuries were believed to to occur gradually over time and therefore

[00:09:03] we took you know one week as the acute period of time and now the listeners can maybe see the

[00:09:09] paradox here because I just said that that we have two different types of overuse injuries those

[00:09:14] that are gradual over time and those that are more acute over time and you really don't capture

[00:09:20] the acute overuse injuries if you use an algorithm to calculate 10 percent where it

[00:09:26] should take how much you have been running in the past week maybe we should more look into

[00:09:31] what the runner has done in a certain running session and make the calculation from there

[00:09:37] and that's where we will take our research in the upcoming years when we define the 10 percent

[00:09:42] not only looking at what runners have been doing in the past week but also what they have done

[00:09:48] just in one single training session compared to what they have done in say the four weeks

[00:09:53] prior to that I think also an interesting thing to consider in clinical practice for

[00:09:58] the GHPG listeners when they they ask the runners not necessarily only ask for what they have done

[00:10:04] in total over one week but also see the spikes in certain running sessions to see if a runner has

[00:10:10] has just increased a long distance from say 10 kilometers which has been the maximum to

[00:10:16] to 20 kilometers because that's a huge spike you mentioned the 10 percent rule that 10 percent

[00:10:22] rule of thumb for increasing training load Rasmus how much is too much running at present we don't

[00:10:29] know so so it's rather uncertain how much running is too much because the evidence currently is

[00:10:37] too too fast to really respond to that question but I can reveal that that's maybe in a half year

[00:10:43] time news new studies from outside will surface on on that matter so I have some ideas but

[00:10:49] unfortunately too early to share at this stage so as a case of watch this space and in the meantime

[00:10:56] perhaps use that 10 percent rule of thumb as a as a bit of a guide I would say some maximum guide

[00:11:01] yes so so exceeding the 10 percent I would definitely not do that and that's a rule of thumb

[00:11:06] right now then then the runner can always look at this training schedule and see what

[00:11:13] exactly is it if it's distance per week I should schedule at 10 percent yes that would be good and

[00:11:19] it's also the longest distance per week that should be considered as a 10 percent that's two

[00:11:25] different metrics they should consider equally important when designing a training group.

[00:11:31] I think that's a really good point to make and it brings us to the training load diary

[00:11:36] and or the training diary and how you capture this information.

[00:11:40] How do you like to capture training load Rasmus and what are your suggestions for people listening

[00:11:46] today? I like using objective measures such as DPS watches or something similar

[00:11:54] to quantify the running we did some studies where we asked runners to self report their

[00:11:59] running distance and then they had a watch where they couldn't see how long they ran

[00:12:03] and runners are unable to you know self evaluate how long they run at least if they run on paths

[00:12:10] they haven't run before so I like to use objective tools to capture my running and then

[00:12:15] I always make a running schedule so I have the idea of how many kilometers should I run per week

[00:12:22] or what's the distance of the longest run and also try to intensity wise not just on the

[00:12:29] distance but also on the intensity try to not make too large spikes in the progression

[00:12:35] and running speed because that could also be dangerous in terms of sustaining an injury.

[00:12:40] So it's gradually building capacity to withstand the load and you do that both on the

[00:12:45] distance perspective but also on an intensity. Unfortunately it's a little bit difficult

[00:12:51] to research into intensity at least based on many of the available tools we have today

[00:12:57] because GPS for instance is not that good at capturing short distance changes in running

[00:13:04] speed so if you sprint for instance that that can be a little bit difficult to to capture and

[00:13:09] enhance research. You mentioned GPS watches Rasmus I think many people listening today many of the

[00:13:16] athletes and patients with whom they work will also have a GPS watch on their wrist.

[00:13:22] When I look at my GPS watch output when I do an activity record a physical activity with it

[00:13:28] I get so many different metrics. Is there any value in interpreting or trying to interpret

[00:13:34] some of the metrics that the watch is capturing? Oh it's a good question Claire currently runs

[00:13:41] a very there's an article called why they call it obsessed with running mileage or distance

[00:13:46] and that's for reasons. That's really simple and it's easy to understand and I think it's

[00:13:52] difficult to avoid talking about distance as an important metric even though as a

[00:14:00] bimiconist you could argue that other metrics than distance would be more valuable in terms

[00:14:06] of defining a load a runner has been exposed to during a running session. So it's a matter of

[00:14:12] should we use the metric that the runners understand and embrace or should we use a very

[00:14:18] very difficult to understand metric hence maybe not as easy to use when they should design the

[00:14:24] training programs. So I'm a little bit split here because as a researcher I really love the

[00:14:30] trying to approximate the load a runner is exposed to in different parts of the body it's

[00:14:36] really the gold standard and I really try to also go down that path. However I also use

[00:14:43] just distance because it's rather simple and everyone can understand it and it's easy for me to

[00:14:49] communicate. Unfortunately we are not aware yet how to use the really huge information

[00:14:57] that that runner receives in the training diaries on various metrics for injury

[00:15:03] preventive purposes at the moment but hopefully over time because the technology evolves and more

[00:15:09] metrics can be measured then we are better at using these metrics in order to make injury

[00:15:14] protective algorithms. And you mentioned runners being very specific and I think you used the

[00:15:21] word obsessive we're not using that in a negative term I think runners love to capture their

[00:15:25] it but I'm also obsessed so it's it's it's positive. Likewise we share that I think many

[00:15:31] of our listeners will also share that too that it's it's that old adage of if it's not on Strava

[00:15:36] it didn't happen. I guess one of the interesting benefits of wearables really taking over physical

[00:15:42] activity and recording many of our physical activity sessions is that knowingly or unknowingly

[00:15:48] we are giving up a lot of our running data or our physical activity data to these companies

[00:15:53] who of course have privacy laws in place that govern how they use those data and I know that

[00:15:58] you've been analyzing big data sets from companies like Garmin so our data can go towards understanding

[00:16:06] what's going on with running related injuries. Can you tell us a little bit about how that works

[00:16:11] Rasmus and the work that you've been doing with these these big data sets? We really need to

[00:16:16] collaborate with industry because the industry has access to a lot of runners and if we need

[00:16:21] to understand what works for who under which circumstances we really really need a lot of

[00:16:27] data not just 100 persons or 500 person or 1000 runners. We need millions and millions if we

[00:16:34] really should make you know the personalized preventive approach where we can guide subgroups

[00:16:40] of runners which is the gold standard from my perspective towards a rather safe running

[00:16:45] regime. Unfortunately many of the companies do not register injuries a part of data collection

[00:16:51] processes so we as researchers we can get the data in case the runner are willing to share the

[00:16:58] data with us and then we can ask for you know health related issues such as injuries and other

[00:17:04] things and then then look into details with this but I think the industry is doing what they

[00:17:10] can and then they're trying to be as open as possible and now I'm based in the EU and we have

[00:17:16] the GDPR Regulative which makes this highly difficult to really access data and share data

[00:17:24] and being open minded towards that so it's not the companies from my perspective that are

[00:17:30] reluctant it's more you know all the GDPR issues and all the medical device problems

[00:17:36] that surface when you try to capture health related information.

[00:17:41] Now we can't talk about running and leave shoes to the sidelines so let's bring running shoes

[00:17:47] now it's all about the shoes. Exactly so does the choice of running shoe have much of an impact

[00:17:53] on injury risk for runners? Church of Running shoe has a huge impact because the shoe will

[00:18:01] retain the load distribution so if you are used running in a certain shoe and you could then

[00:18:07] pick another shoe which is vastly different from what you're used to then you expose

[00:18:12] different parts of the body to load and you should be cautious introducing the new shoe

[00:18:18] because the body is not used to the loads in those certain structures so it's not about

[00:18:25] it's the shoe that causes the injury because that would then collide with what we just said before

[00:18:31] that it's a matter of running too much for instance with a certain shoe so it's not that the shoe

[00:18:37] that causes the injury but it's about running too much in a certain shoe that causes the injury

[00:18:43] and then if you have a certain shoe you run in then if you run much more in your usual shoe

[00:18:49] than you're used to then your injury risk will be high but you could also run in a totally new shoe

[00:18:55] and then you could not run that much before you are at high risk of sustaining injury

[00:19:00] so it's a matter of how much load you're able to tolerate depending on which shoe that you choose

[00:19:06] to run in. Unfortunately research on the pinning this is rather sparse at the moment so we are

[00:19:12] not aware of how much running in terms of for instance distance are a runner able to to expose

[00:19:19] him or herself to when changing to a completely different shoe because of course running shoes

[00:19:25] plays a role but it's not because of the shoe that you sustain injury it's because you run too much

[00:19:31] in a certain shoe. When we're talking about injuries we can't not talk about injury prevention

[00:19:37] just like we can't not talk about shoes and running so let's put some of these ideas together.

[00:19:43] What can runners do to stay healthy? What are your tips for preventing running related injuries?

[00:19:49] It's based on of course a little research but then very much my personal ideas and preferences

[00:19:55] so I don't have even know much evidence support based on what I'm going to say but

[00:20:00] I think runners should be aware that sudden changes in certain types of variables could be the running

[00:20:07] distance, they could be changing their running shoes, they could be changing their surface,

[00:20:13] they could be change running terrain. If they change something do that gradually and slowly to

[00:20:19] reduce the risk of sustaining injury because if you do not introduce something new gradually

[00:20:25] over time you will have a high risk of sustaining injury for instance if you just run what you're used

[00:20:32] to in a new shoe or if you switch from asphalt running to sand then it's a vastly different

[00:20:38] load distribution when you run in sand and consequently you can't run that much in sand

[00:20:43] before you sustain an injury. It's the same with terrain if you live in an area where

[00:20:48] it's really flat and then you go on vacation to a very very hilly terrain

[00:20:52] you should be very perccious because you're not used to running in hilly terrain and you should

[00:20:57] not run as much and then you should try to seek flat terrains where you stay at your vacation

[00:21:03] and then slowly introduce the hilly terrain. So my recommendation to runners would be to consider

[00:21:11] what changes do I do over time and when you make some change either buy a new shoe or run on

[00:21:19] different terrains or surfaces run with a stroller or backpack or whatever it can be

[00:21:25] make the change slowly and I would say from a theoretical perspective that the risk of

[00:21:31] injury will be lower than if you introduce it just like this and you run as much as you're

[00:21:37] used to in a new scenario. And Rasmus what's the value of strength training for runners? I think

[00:21:43] a bit like cyclists runners are often running a lot of mileage and not doing so much in the gym

[00:21:49] and some people really are concerned about doing too much in the gym so where does the

[00:21:53] research sit on strength training and running related injuries? We don't know that much a lot of

[00:21:59] people go into the domain that the strength will build your capacity and then you are more

[00:22:04] resistant to watch load when you run if you have a stronger body but currently I haven't seen any

[00:22:10] larger data sets that confirms that there's stronger capacity amongst the runners also

[00:22:17] leads to a higher tolerance towards the load exposed to the body when you run so I don't know

[00:22:23] but it's certainly an interesting area and heavily debated out there. And we should say that strength

[00:22:28] training of course has lots of benefits and is included in the physical activity recommendations.

[00:22:33] In another perspective yeah I think lots of governments now follow the WHO guidelines which

[00:22:39] also encourage children, adolescents and adults as seniors to to strength training here two to

[00:22:47] one is a good idea. Rasmus this has been a fascinating discussion with you about running

[00:22:52] related injuries and the broad nuances of training load and and how to protect against

[00:22:58] injury I want to say thanks so much for bringing your insights to the podcast today

[00:23:02] and thanks for joining me on JO SPT Insights. Thank you very much Claire it was a really

[00:23:07] really good pleasure to being on call. Thanks for listening to this episode of JO SPT Insights

[00:23:16] for more discussion of the issues in musculoskeletal rehabilitation that are relevant to your practice

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