calming supplements & the placebo effect

I had a really tough ride on Suzy this week, which led me into a discussion with my barn manager about possibly giving her another dose of depo.  Barn manager suggested that since I spend a lot of time with Suzy, I’d be able to help Suzy’s owner decide if her behavior warranted another dose.  Now, there’s not a lot (almost none, but perhaps there is something I haven’t dug up yet) of evidence that depo actually does anything in horses, despite many, many, many anecdotes to the contrary.  Absence of evidence isn’t evidence of absence, but I’m not really one to go adding hormones to someone’s lifestyle without a pretty good reason.

seemed appropriate here

This led me to think about the hundreds of calming supplements and treatments available for horses that have little to no evidence of a significant (or even potentially biologically relevant) effect upon behavior.  Hell, I use one of them!  Yet so many of us cling to these supplements and swear up and down that they are doing something.

But the placebo effect is a strong and very legitimate thing. Whether or not the placebo effect is causing actual physiological changes or is being exploited by companies to sell sham products, it is a very easy trap to fall into. Most of us are going to add calming supplements to a horse’s diet after they’ve been particularly wild and crazy for some amount of time — maybe a week’s worth of rides.  But if those particularly wild and crazy days are outliers, or even just somewhere on the edge of “normal” for that horse, then his behavior is going to trend back toward normal whether you add the calming supplement or not.  Those days were abnormal, and unless there’s something else significant going on to change the horse’s behavior (totally plausible — but not necessarily the case), the added calming supplement most likely did nothing.  The horse’s behavior was going to go back toward “normal” anyway.

big spikes of bad behavior like this == abnormal

Let’s say that we rate Murray’s badness on a very scientific scale of 1-10 each day: 1 is totally normal, no bad behaviors performed, 10 is rearing and striking.  (For the record, I’ve never experienced either a 1 or a 10 day.)  If Murray tends to hover around a 3.5 because he likes to get down with his bad self, but suddenly spikes up to an 8 one day, I’m likely to dump a bunch of extra magnesium in his bucket for a few days.  And then, because being a level-8 bad boy is a really unlikely occurrence, we just slide back toward the average. Which is both statistically and realistically much more likely to occur on any given day.

Especially because the way we think of behavior (or anything with a gradient, basically) tends to fall on a bell curve.  If we assume that each behavioral category is roughly on standard deviation away from the next, it means that behaviors in the “average” category occur 68% of the time. Behaviors one more standard deviation away from average occur with 95% frequency.  If being slightly nutty or slightly better than average is occurring with 95% frequency, any time you have a bad day, you have something approaching a 95% chance that your next ride will be better (assuming the two days are independent, which they aren’t).

So when we’re adding calming supplements, or more invasive approaches to calming behavior, how are we to know if we are really doing anything?  There are ways to test it — you could blindly rank your horse’s behavior every single day that you spend with him while another person either gives him that supplement or a sham supplement. Then you’d compare the distributions of behaviors demonstrated.  I just turn to the science.  Of course, there’s really not a whole lot of peer reviewed research in this area, which is frustrating.

All of this is not to say that I don’t believe in calming supplements or that diet can change behavior.  Obviously I do, and there are some behaviors that I have seen decrease rapidly with the right change in diet.  I am completely certain that if we mapped Murray’s behavior when he’s on alfalfa and compared it to his behavior off alfalfa, we’d see a significant difference.

even walking is hard when Murray eats alfalfa

But it does mean that I approach adding supplements like this with a fair bit of caution, and I pretty much don’t believe what I read from testimonials on the internet.  People are notoriously bad at understanding probability and statistics without training in those areas, and we love just-so stories.  We also really, really want to help our horses, and they can’t talk to us and say “I’m feeling a little extra girthy today, how about you take it extra slow while we tack up?” (I mean, sure, he does say that to me. It’s just usually while I’m tacking up and it’s a leeetle bit too late.)  It also means that I don’t pay too much attention to any one ride, or even any one week, when making decisions about this stuff.  One day is an outlier.  A whole week… could easily be a rough week.  Especially when there’s other stuff going on in the world that might influence behavior more than supplements do — changes in turnout, routine, weather… I’m seriously convinced that when the barometer drops, Murray’s brain swells and hurts his little head, because he’s usually much worse before a storm than during!

I may also use this logic to aggressively convince myself out of using supplements that might help. When barn manager originally told me to take Murray off alfalfa I was like “NAW THAT’S NOT A THING”.  Same with adding magnesium.  And both of those things had a huge positive effect on Murray’s general outlook on life.

So, how do you approach adding and subtracting supplements like this?  Just go with the prevailing wisdom? Trust your gut? Appeal to nature?


usea convention notes: boyd says

Phew. These clinic updates are turning out to be farther between (though hopefully not fewer) than I anticipated. Why does real life have to be so fucking busy?  I don’t even know.


Friday at Convention was one of two main lecture/talk filled days, and included an Adult Amateurs Open Session.  I came into this session a little late, and when I got there Bunnie Sexton was answering questions from people in the room.  For me this amounted to a low-interest discussion of different jumping exercises that she keeps in her arena at all times (I’d much rather get that info through a lesson, it’s always just a little weird to me to just talk about these things without the context of the horse), and a moderately interesting discussion of how to shop for a safe, fun, and trainable Novice-level beer buddy.

But then we had a surprise speaker come in, and it was BOYD!

File:Boyd Martin Otis Barbotiere cross country London 2012.jpg

If you haven’t watched his keynote, it’s live on the USEA website now.  It was a great one — funny, endearing, full of adventure.  The only thing it could have used was more pony pictures!  And yes, he’s just as adorable and dreamy in person.

Boyd made a few comments that were pretty interesting, so in case you missed the live stream (I’m not sure there’s a way to watch it now, after the fact), here’s a few of my notes.

It’s a privilege to feel stressed

Boyd’s first comment about being an adult amateur is that the stress we feel during horse shows or before cross country is a privilege. We do this because we love it, and it’s a hell of a lot better than sitting on the couch watching Nascar drinking Bud light (his words!).

We get to do incredible things because of the strength, speed, and power loaned to us by horses.

The flip side of this, to me, is that if we don’t appreciate or feel privileged to have that stress… maybe we’re doing it wrong.

On blood rules

One rider asked Boyd about warming Crackerjack up in a hackamore at Rolex. Boyd responded with a story about Crackers coming out of dressage at Badminton with a little blood in his mouth because he would get so tense and forcefully brace on the bit in a show environment.  In this case, the official noted that it was a really tiny amount of blood and didn’t eliminate the pair.  But because of that incident and Crackers’ obvious self-injurious tension during shows, Boyd started warming him up in a hackamore. (Evidently this had the positive side effect of unlocking a better way of going for Crackerjack too, so it was a win-win.)

So I asked a follow up question about his opinion on blood rules. What did he think of them as they currently stood?  What about repeat cases?

Boyd responded without any real specifics. It’s eventing, and injuries can happen anywhere (especially on cross country) and in all kinds of interesting ways.  It should be evaluated on a case-by-case basis, and blanket eliminations might not fit all cases.  Bland and politically correct?  Certainly.  But there were little nuggets in there.

Boyd saw that his horse could incur an injury from a piece of his equipment — however strange and rare the injury might be — and changed his equipment to prevent injury to the horse (and subsequent elimination).  If nothing else, I would expect that to be the standard he holds other riders to.

You can improve him, but you can’t change him

In response to a question (sorry, can’t remember the exact question), Boyd said that an important thing to remember with horses is that you can improve them, but you can’t change them.

He gave an example of an OTTB he rode who jigged in the walk during the trial. He thought, no big deal — we can relax him and get the jig out.  But every time they had to walk in a dressage test at a show, that jig came right back out.

I’m don’t think Boyd meant “you can’t change anything” about a horse.  But in times of stress, we always see those habits coming back.  A horse whose inclination is to pull and gets heavy is going to revert to pulling and getting heavy when things get tough.  A  horse whose inclination is to invert is going to invert when the going gets stressful.

It made me think a lot about what traits I’d want in a future horse, and what habits I’d be willing to live with.

Be better

My favourite piece of advice from Boyd.  He sees a lot of amateurs bombing around the lower levels on a horse who is capable, just getting by, doing okay, but also being a little bit sketchy, maybe even dangerous.

Try harder, he said. Ride better, improve your skills, improve the way your horse goes.  Hold yourself to a higher standard.  Don’t accept winning just because your horse can get around.  Just keep getting better.

usea convention notes: level creep

One of the most interesting discussions (for me) at convention was the Course Builder’s forum.  There were some good updates on new rules (frangible pins, measurement of top spread on angled lines) and then a pretty informative discussion on “level creep”.

I first learned about level creep in 2014-ish when the proposed rule to have 1 or 2 fences on XC and stadium that exceeded the max height for the level by 2″ came up.  In my recollection, people were concerned that this constituted another excuse for level creep and making levels too challenging for the horses and riders competing at them.  My opinion of that was that if  horse is running around a 2’7″ XC but can’t safely clear one simple 2’9″ fence, then they probably can’t really safely run that BN course. 2″ should NOT make that much of  difference on a straightforward question. That opinion is even stronger now that I am more experienced at both riding and have a deeper understanding of  how courses are built and managed.


we’ve come a long way!

So, let’s start with the basics. What is level creep?  For the purposes of this discussion, I’ll define level creep as the steady increase over time of the size of fences and difficulty of questions on rated XC courses across the country.  Just in case it wasn’t self explanatory enough.

Why do we care about level creep?  It depends who you are. If you’re a rider who sees courses becoming larger and larger in front of your eyes, maybe you feel like you’re being sized out of your division.  If you’re an organizer, you are hearing people complain about your courses, and wondering how you can keep people happy and safe.  If you’re a course designer, you’re trying to build courses that help riders be successful but also meet the requirements for the level.

And maybe, no matter who you are, you’re wondering “WTF is this even real?”

this fence measures at the appropriate height for BN (2’7″ with 4″ brush)
but it is technically too challenging for the level, based on the downhill approach and jump toward the spectator area

So is level creep real? In short, yes. But also no.

The overwhelming opinion of the course designers and officials in the forum is that we see true level creep only when courses have been existing at too low of a level in the past.  Certainly, those course are getting bigger and more technical, because they weren’t big or technical enough in the past.  And this, in and of itself, is a problem.

First, it’s not fair to have riders across the country competing at the same level (be it BN or Prelim) on courses that are different sizes.  If someone is jumping around 2’3″ or 2’4″ getting their BN points while other people are only getting Intro points for that height, that is inherently not fair. (And yes, everyone acknowledge that this happens, even if sometimes rarely.)

Second, allowing riders to feel that they have become competent at a level on courses that are under-sized and under-technical is doing them a disservice when they either visit other venues or try to move up a level.  Running 2’4″ cross country does not prepare you for a real 2’11” Novice course.  This was seen as a problem mostly at the Training and Prelim levels,  because the jumps to Training and Prelim are so big.

still a nice-sized fence, but on a much friendlier straight-away and level approach

If a level at a venue is creeping up to the national standard, can that really be considered level creep?

Course designers don’t want people to struggle (or worse, fall) at any level. But that’s not all on the course designers, is it?  And making courses smaller in order to accommodate what people in the area are used to or interested in riding is doing a disservice to the sport.  So they look at their results, evaluate their courses, and adjust within the requirements for the level as necessary.

Across California, I (and other professionals and officials) have noticed courses becoming smaller and more appropriate to the level at Training and below. This is a reflection of course designers and organizers acknowledging the problems in their courses and making changes.  This is the same process that the same course designers are going through at other venues in other areas, but instead, they are increasing fence size or technicality.

beginner novice fence 3 — under 2’7″ as it’s on a downhill approach
(you measure from takeoff, not the base of the fence)

What does this mean for riders?

For me, it confirmed the idea that level creep is mostly a non-issue.  I trust my course designers and officials — who are required by the USEA to change with regularity at each venue — to keep things within the requirements of the level, while giving an appropriate challenge for the level.  But what about you?  Have you experienced level creep? Do you see it clearly at events you attend?

But it also means that our voices are being heard to make changes.  When the courses in California were too technical and too big (four-ish years ago), riders and trainers made comments on the official USEA comment forms and personally to officials.  And course designers stepped up, re-evaluated, and fixed it.

If you’re a rider who is concerned about a question at the level, there are a couple of things you can do.  First, whip out your measuring stick and measure that bitch.  Fences are measured by putting a level on the top of the fence and measuring the height from the ground at the average takeoff point (six feet away and center), or landing point (for drops).  From the base of the fence itself, depending on how it’s set in the ground and how level the approach is, there can be 4″ or oven 6″ of variation.

the same fence as above measures above 2’7″ on a level approach,
and makes a nice, friendly Novice question for the beginning of the course

Second, if you really feel that a fence is not appropriate for the level based on your measurements, approach an official or course designer.  At the very worst, the official will tell you that the fence is appropriate and that will be that.  Possibly, they will talk to you about the elements of the fence that make it appropriate within the level.  Possibly, they’ll make a change — whether that means swapping out the fence, adding sand to raise the takeoff, or removing it from the course entirely.  This goes for fences that are not appropriate for a level because they are too small also.  How many of us would complain a bout a gimme fence on course?  I never have.  But those fences also add to the perception of level creep — because if I’m jumping a 2’3″ coop at Novice and thinking that’s appropriate for the level, obviously a 2’11” table is going to be a big change for me and my horse.

During this session the course designers also discussed making themselves and their contact information more readily available and visible at events.  They want to hear from us if we have concerns, because this is the immediate feedback about their work that they need. It also gives them an opportunity to help educate riders and trainers.

This sport lives on the backs of the lower level riders.  As riders, we want to be here, and as organizers we want you to be here.  This should be fun, but it should also be the good kind of challenge.

I think there will probably always be people who complain about fence size at the lower levels — it’s just the nature of having a lot of amateurs in the sport.  Or perhaps it’s a reflection of something that I’m not seeing.  Are you concerned about level creep?  Are there aspects of this that I’m missing?



are we having fun yet?

California is casually on fire right now.  Everywhere.  But mostly in wine country, which is especially hard because it’s hilly, winding, rural, and full of livestock.  And also because it means wine will be at least a little harder to come by in the not-too-distant future.

Riding non-Murray horses has been interesting.  I’ll give any horse a couple of rides before making any sweeping judgments, but sometimes you get an idea of what a pony is all about in as little as one ride.  Sometimes as soon as you sit on them…

i had a ton of fun on this bay nugget during our very first ride together. a good omen.

But what is it about riding one horse or another that is fun?  Obviously riding my horse is fun because I know all the buttons and how to press them.  We’ve also gotten to a point where I understand exactly how much to push and how much to give, so we can start to work on a few steps of really quality work that just seems to get better with every ride.  Obviously that is fun.

So what about with other horses?

Take the mama-mare I’ve been riding the last week or so as an example.  Our first ride together was… lackluster.  She fought me walking away from the arena gate (on foot and under saddle), and was magnetized to the barn-end of the arena like crazy.  The only place I could work in any semblance of a steady pace or shape was smack dab in the center of the arena.  I rode for like ten minutes.

the mom bod is strong with this one

A couple of weeks off and good fistful of rides later and this girl is my main squeeze at the barn.  She’s smart, sensitive in all the right ways, and learns really fast.  She also has a mean right drift, gets locked over one shoulder or the other really easily, and hasn’t quite figured out how to give to pressure instead of leaning in to it.  (Yeah, homegirl, you do have to move over when I put one leg and one rein on simultaneously.)

But it’s always fun riding her.  Even in the tough moments, when we can’t seem to walk in a straight line consistently, or my requests to get off my leg are met with weirdly strong mare abs.  Maybe it’s because it’s easy to see and feel her thinking and processing what we’re working on.  She also feels really honest and like she’s trying, in the moment when she’s not being openly defiant.  She slows down to think when I ask her to, responds to my seat… really, just my kind of ride.

In contrast, a certain Barbie Dream Pony I’ve also been riding lately has not been quite as much fun.

Image result for haflingerbreed hint: it rhymes with pfefferlinger.

Interestingly, the BDP has the same mean right-shoulder drift and locking mechanism that the mama mare seems to have.  He is smart and food motivated, and he learns… well, not super fast, but he’s not a moron.  And I’ve ridden him fewer times than the mama mare, so maybe that is contributing to our lack of jelly.  He’s not mean spirited or dangerous in any way, but I kinda get the feeling that he’s not listening to me.  That he’s just phoning it in.

So maybe that’s the reason I don’t have as much fun with the BDP.  A big part of our rides consist of me trying to convince him to pay some attention to what I’m trying to tell him so that we can actually get something done.  I think we all know that it’s frustrating to be ignored.

Now that I write it out, I think there really is something to this.  That I have more fun on a horse who seems like they are listening.  Because the mama mare basically doesn’t canter for more than one big circle at a time right now, and she’s almost as much fun to ride as my own horse.  But the haffie, who is capable of executing all three gaits, is just… not that fun.  Riding my friends’ horses also can go either way in this regard — sometimes they just don’t know how to listen to me because they’re so in tune with their person and I’m NOT that person.  And sometimes you get really good instructions and they listen to you perfectly and it’s AMAZINGLY fun.

What about you?  What makes a fun ride for you guys?  Is it as intellectual and annoyance based as me?!



I have a vivid memory from when I was a small child (yes, even smaller than I am now!) of walking on my family’s property and coming across the herd of four horses they owned.  I remember this story not only because it was such an important incident in my small life, but also because I retold the story many times after — which we know makes a “memory” stronger.  We were walking through one of the paddocks (translation from Australian: a fenced area bigger than the entire property my horse lives on. Seriously, the farm was 6,000 acres and this paddock took an hour to meander across at my child’s pace) with my aunt, owner of the horses, probably my sister, and some other adults.  We were near the horses but not exactly underneath them, and something spooked them and they took off.  I remember this so clearly not only because a pony spooking is alarming to a sub-4-foot child, but also because my aunt grabbed me across the body and pulled me in close to her, I assume now to avoid the potential crushing of not-her-child under the unpredictable feet of her horses.

we were wandering somewhere out toward those hills

At the time it was so sudden and I marveled at my aunt’s ability to essentially pluck me out of danger’s path before the danger itself was apparent.  Now that I’m more familiar with horses, I know that there were probably a number of other factors that helped her predict the event — a windy day, horses already on edge, probably at least one dog sniffing around and likely to flush a bird from the grass.

For one of my odd-jobs I help a local woman with her three yearlings.  She also has two 2-year-olds that live in the same, big, 6-acre pasture.  The five of them usually come galloping in to me when I show up at the gate or call them, and it’s funny to think how recently I would have shielded myself behind the gate for such antics.  My confidence around horses has grown tremendously, even since becoming a regular rider and comfortable handling multi-horse situations.  Working for my trainer and mucking the paddocks (translation: American paddocks, aka the little ones) for the just-raced-yesterday ottbs, turning horses in and out at my barn, playing with young horses — I’ve had lots of opportunities to watch horse behavior.  I know that the youngsters will stop or split or wheel before they get to me with any speed, and that they are always happy to see me.

I love when the children run to greet me at the gate

A post shared by Nicole Sharpe (@nicolegizelle) on

It’s pretty nice to walk in among the kiddos and scratch here and there and get a bit of loving from them.  Both of the two year olds will always make groomy-lips when I start scratching their withers or midline, and will take the opportunity to exercise their groomy lips on anyone who walks by.  It’s actually insanely adorable, and I’m so sad that my phone camera is too zoomed in to get any good video of this action.  Especially because one of the 2 year olds is a giant 17hh beast already, and he’ll just grab on to the yearling gelding’s neck and start grooming away.

I’m still figuring out nuances to their body language, of course.  The smaller 2-year old started positioning his hindquarters to me about a week after the 1- and 2-year olds were first put in pasture together.  I got annoyed at him at first, because I had no desire to be kicked, and it’s rude to point your kicking apparatus at friends for no reason.  Then I realized that the bigger yearling mare is actually top baby in the pasture, and she loves to follow me around — so the 2-year old was positioning himself for a quick getaway from her.  When the bossy baby came after the little 2-year old with her mouth open (I should point out that he’s not actually little, he’s just littler than the giant) I was more than happy to step in on his behalf and push her away from both of us.  They can settle their little dominance disputes however they want when I’m not there, but nobody makes snarky faces at me in pasture.

Who’s top pony? I’m top pony.

murray obviously agrees

I wonder if the deep understanding and nuance that we can start to read in equine relationships contributes to the impression that some people have about a magical, wordless, on-a-higher-plane relationship and connection that one could hypothetically have with a unicorn horse.  I was probably as astonished when I saw someone wave their arms to fend off galloping horses as I was when my aunt saved my life.  And if you think about it, it’s pretty incredible that we can see an 1,000 pound beast approaching at a high rate of speed and throw our hands up in the air to divert their course from right on top of us.  What the inexperienced novitiate doesn’t know, really, is that running on top of humans is squishy and likely not the ideal footing for a horse, and that they especially don’t want to run on something that looks like it might be bigger and even less predictable than it currently appears.

Learning is funny like that.  To the uneducated, it seems like magic.  To the initiated, it is almost mundane.

Image result for beastmaster

But I still think of myself as a motherfuckin’ beast master any time I lead more than two horses in from the pasture in one trip.



craniology, part 1.5: the force of a falling object

Thanks to Amanda’s super Sunday Blog Roundup, I found this really interesting article from Eventing Nation about what a helmet will and won’t do to protect you in a fall.  It was incredibly fascinating and well worth the read, but left me with a couple of questions:

First, what are the forces at which the helmets in question were tested at when they failed the impact tests?

Second, what are the forces that are frequently experienced by an equestrian falling off of their horse?

gravity can be a real bitch

I couldn’t find any answers to the first question, which is an important one to me.  If the authors were testing helmets at 10,000 gs (G-forces) and they fail to protect the head against two impacts at that force well… that’s unrealistic.  But if the authors were testing helmets at 350 gs (a force easily acquired by an object falling from 3.5 meters with a stopping distance of only 1 cm), then that’s a much more reasonable test.  Fear not, I’ve emailed the main author of the study to get a little more information about how they conducted their research.  I’ll update you when I find out.  (I did discover that they use a really funny machine to test these things!)

To the second question, the answer is: it turns out it depends.  The basic calculation of g-forces involves the rate of deceleration and the force of gravity.  Rate of deceleration can be calculated by using velocity and stopping distance.  And therein lies the rub: stopping distance is highly variable on difference surfaces.  For example, when you drop your phone on asphalt, the stopping distance is basically just the crunch factor of your phone — as little as 1-2 mm in some cases.

The other complication is that there are multiple force vectors at work when you fall off a horse.  Not only do you fall from some height to the ground, but you also stop your forward motion — motion that can vary from 300 mpm (slow canter) to 600 mpm (Rolex gallop) depending on the speed you’re moving.

lets not forget all the physics lessons Murray has given me

I took physics (twice), though, and was pretty confident that I could figure out the force vectors, so set about determining the g forces likely experienced by helmets and riders falling at different speeds.  G forces are a convenient unit to calculate this in, since they are the same no matter the mass of the falling object — and that’s the unit in which the “brain trauma” numbers were reported.

The set up

You can use this handy-dandy fall force calculator from VaultCanada if you’d like to calculate g-forces of objects falling straight down.  It doesn’t add it in horizontal movement, but it is a bit of fun to play around with.

Then there are the basic equations.  I didn’t actually consult a physics text book, but I did use the VaultCanada site (linked above), the physics classroom, and the engineering toolbox.  Pertinent equations are below.


Pythagoras will help me with that last one

There are a couple of other caveats here.  Because I was using physics equations, they aren’t taking into account any of those pesky real-life forces like friction (ground or air), the oddity of the human/horse shape, what part of the body hits the ground first, etc. etc.  We are also not taking into account the fact that different parts of the body are likely to encounter different amounts of force by landing at different times.  Just assume that the hypothetical human in these equations always lands directly on their head.  So we’re working with a frictionless, lawn-darting, spherical humanoid riding in a vacuum.  You know.  A really realistic one.

Also, I could be wrong. There aren’t any internet resources that confirmed my plan to add these forces using the Pythagorean theorem.  I bulled ahead regardless.

Also, force vectors for helmet calculation will be pointing in toward the object.  Because what we are interested in is the force the surface is exerting on the object (one’s head, for example) during the stop*, so the force vectors should be reversed from the above image.  It doesn’t affect the calculations.

*You know that old joke about cliff jumping.  It’s not the long drop that kills you; it’s the sudden stop at the end.

With that information, let’s answer a few of my burning questions about forces and riding!

We’ll start with an easy one.  If you drop the helmet on the ground, are you really voiding the protective abilities of your helmet?

Let’s say you’re about my height (1.5 meters), and drop your helmet from your hands (about 1 meter high) on to arena sand, which compresses about 2cm when the helmet hits the ground.

100 cm / 2 cm = 50 gs of force

If the stopping distance decreases to 0.5 cm (5 mm)

100 cm / 0.5 cm = 200 gs of force

I don’t actually know how much force the outside of a helmet can withstand.  But 200 gs is well below what a helmet is supposed to protect you against (300 gs), and likely below what the helmets are tested at.  I’m not going to make any declarations about the safety of a helmet after being dropped on anything but arena sand — which I don’t think is the end of the world.  (When some butterfingers drops her helmet repeatedly on the barn aisle though….)

More pertinent to humans, if someone falls off of a horse onto arena sand, what are the forces experienced by their helmet?  And by their head?

First, what height are they falling from?  Let’s say we have a 16.2 hand horse, and the human’s head is 2.5 feet above that height — like a medium-height person sitting on a relatively tall horse.  That’s 241.2 centimeters high.  Let’s stick with that 2cm stopping distance again.  Without any horizontal motion (i.e. horse is standing still and our spherical rider just falls off the side):

241.2 cm / 2 cm = 120.6 gs of force — a not insubstantial amount of force, but not enough to for sure cause a serious brain injury

If the helmet foam compresses by 2mm during the impact, then the head in question experiences a slightly different amount of force

241.2 cm / 2.2cm = 109.6 gs of force — a pretty awesome decrease, thanks Charles Owen!

What if you fall off at the peak of a fence?  My head was about 292 cm in the air at the peak of that charming 2’6″ fence above (I used a really specific measuring system called PowerPoint), so if we go with our previously calculated stopping distances

292 cm / 2 cm = 146 gs
292 cm / 4 cm = 73 gs

Okay, let’s talk horses in motion.

In stadium, posted speeds vary between 300 and 400 mpm — I think? I’ve never really paid attention except when writing up programs — which is well within the range of a canter.  Let’s say that rider and pony have an unfortunate parting of ways at 350 mpm involving a dirty stop, and our lawn-darting, spherical rider goes flying over pony’s head and on to the ground, where she skids for 30 cm (1 foot) in arena sand that compresses to 4 cm (a little more cushy than the aforementioned arena sand).

vertical forces = 241.2 cm / 4 cm = 60.3 gs
horizontal forces = (5.8 mps)^2 / (2 * 0.3 m * 9.8 m/s/s) = 5.7 gs
Pythagoras says: combined forces = 60.57 gs

That’s really a fairly gentle fall, all things considered — barely more significant than falling off your stationary horse.

What if we jack up the speed to 520 mpm?

vertical forces = 60.3 gs (same as above)
horizontal forces = (8.76 mps)^2 / (2 * 0.3 m * 9.8 m/s/s) = 38 gs
Pythagoras says: combined forces = 71.44 gs

All in all, it seems like falling in soft, squishy footing in stadium (or dressage, I guess) isn’t all that awful.  4 cm isn’t even that deep of an impact crater.

Cross country is where things get sketchy.

Cross country footing is nowhere near as squishy as stadium footing, so I’m conservatively estimating a 1 cm vertical stopping distance.  This drastically increases the vertical forces right off the bat.

vertical forces = 241.2 cm / 1 cm = 241.2 gs

If our spherical rider falls off of her horse traveling at 400 mpm, and stops in a distance of 10cm (skidding), then

horizontal forces = (6.67 mps)^2 / (2 * 0.1 m * 9.8 m/s/s) = 22 gs
Pythagoras says: combined forces = 242.26 gs

If said rider is traveling at 600 mpm and has the same stopping distance (10 cm), it looks worse

vertical forces = 241.2 gs
horizontal forces = (10 mps)^2 / (2 * 0.1 m * 9.8 m/s/s) = 51 gs
Pythagoras says: combined forces = 247 gs

Let’s say that the helmet our hypothetical rider is wearing compresses by 2mm (0.2 cm) during the impact, as above.  Then we get

vertical forces = 241.2 / 1.2 = 201 gs
horizontal forces = (10 mps)^2 / (2 * 0.102 m * 9.8 m/s/s) = 38 gs
Pythagoras says: combined forces = 208 gs

Once again, that’s an appreciable decrease in force caused by only a 2mm compression within the helmet.  Helmets are cool, man.

I ran out of fall-adjacent media

Just for shits, here’s what happens if someone traveling at Rolex speeds falls and has a stopping distance of only 1cm (maybe they hit a fence, I dunno)

vertical forces = 214.2 gs
horizontal forces = (10 m/s)^2 / (2 * 0.01 m * 9.8 m/s/s) = 510 gs
Pythagoras says: combined forces = 563 gs

Helmet compression of 2mm decreases this impact force to 395 gs, which is a really appreciable decrease.  As if I needed more reason to wear a helmet — gotta protect that money maker.

These estimates are probably not all that realistic, given the many caveats I had to list above.  I’m also not taking into account multiple concussions, bouncing, being kicked by horses, hitting other objects… Really, there’s a lot more that could go in to this model to make it more accurate (though as we know, the more predictors you add to a model the less predictive it actually becomes — statistics is a cruel mistress).  But it was an interesting exercise in practicing physics and geometry again, and gave me some idea of the serious forces we put our heads under.  Thank you, helmet, for protecting my melon so often!

(Now I have other questions. What forces are needed to break certain bones, for example?!)


reconsidering pentosan

Since Twin, I’ve been thinking about what I might be able to do for Murray to make him more comfortable and extend our competition career.  A part of what inspired me to start thinking about it more seriously was his super-stardom at Twin, but I also have a lot more income than I ever have in the past. This makes entertaining the idea of spending/potentially wasting money on my horse’s well-being possible — I literally* did not have the money to pour money into joint maintenance before.

* The actual literally, not the millennial “literally” that really means “figuratively” or “maybe”

I first heard about Pentosan on Amanda’s blog (like, where I hear about most things apparently), and after following the trail of evidence she left, I wasn’t terribly convinced.  Use of the drug was based mostly on anecdotal reports of improved movement and comfort after IM/IV injections among Australian horse owners, and there wasn’t a ton of peer-reviewed evidence to back up using Pentosan IM/IV for joint maintenance.

murray is a skeptical walrus

Pentosan, if you’re unfamiliar, is a semi-synthetic polysulfyated xylan (don’t know what that really means? me neither!).  It is used for several purposes, including treatment and prevention of osteoarthritis.  The most interesting thing, to me, about pentosan is that it is used during open-joint surgery to help heal the joints after they are put back together.  Literally, surgeons squirt the stuff all over the open joint to help avoid cartilage break down and improve synovial fluid viscosity.  edit: Austen pointed out to me this important clarification: joint lavage (which is done both surgically or arthroscopically) works by helping to wash away debris that accumulates in the joint and may cause pain (at least in humans).  Therefore, the pentosan may not be having as much of an effect as might be reported — the lavage process itself is extremely helpful in this case.

I’m won’t rule out a treatment or medication as ineffective simply because it doesn’t have veterinarian or peer-reviewed evidence.  I know that it takes time to conduct studies and gather data, and that what is currently being studied may not be what is in vogue with horse owners at the time.  Joint pain and comfort is terribly hard to quantitatively evaluate, especially when you want to look at more than just the articulation of a specific joint (how far that joint can flex/bend), and supplements/drugs for joint pain in companion and production animals aren’t necessarily at the top of the research ladder.  Particularly in equines, the amount of scientific inquiry into the efficacy of drugs or supplements is quite sparse.

All that said, I’m not going to rush out and spend a lot of money on a product that is anecdotally reported by horse owners to make their horses “feel better”.  The placebo effect*, even among animal caregivers and owners, is a real thing.  (Also in 2014 my horse was five, not actually mine, and it wasn’t the time to think seriously about maintenance.)

* Have just realised this could make an incredible horse name!!

placebo effect is sooooo good at canter poles

When I started thinking about and exploring joint maintenance for Murray this year, pentosan popped up both on the interwebs and at the suggestion of a friend.  I took some time to look into the drug more seriously, and found that in the last three years, enough evidence about the efficacy of pentosan in prevention and treatment of OA has accumulated to convince me it’s worth a try.  If you’re interested in my research, just hit me up and I can share the details with you.  But here are some of my more general findings.  (Links here may be behind a paywall.)

First of all, pentosan appears to be safe to use in  horses both intra-articularly (i.e. joint injections), as well as IV and IM.  That’s great, because it means that you don’t have to pony up for expensive IA injections just to get the drug, an if you can’t do IV, you can safely go IM.

There is also good evidence that IM pentosan actually makes its way into both the plasma (blood) and intra-articular spaces (joints).  And in dogs, pentosan has been used to successfully treat chronic osteoarthritis.  If you want to dive a bit deeper into the cell-biology literature (exposing oneself to some serious jargon at the same time), there’s at least one proposed method for pentosan to treat osteoarthritis by acting as a chondroprotective agent (cartilage protective agent).

unrelated puppy throwbac pic

Pentosan was demonstrated to modify the healing of experimentally-induced OA in donkeys and horses.  In these studies, donkeys and horses with experimentally induced OA were given IV pentosan (treatment) or saline (control).  At the beginning of the treatment period, all animals were lame, and their levels of lameness, synovial fluid, cartilage damage, and the levels of certain elements (Mg, Ca) were tracked over time (among other factors associated with joint health).  All of the above mentioned factors improved significantly in treatment animals, i.e. synovial fluid was decreased compared to controls, cartilage damage was less.  Most importantly to me, lameness score in treatment animals decreased to baseline (which I believe was 0) after pentosan treatment, whereas in control animals lameness score decreased, but never achieved baseline levels.

Certainly, this is a pretty extreme way to check the utility of pentosan.  And it doesn’t necessarily speak to the maintenance side of the drug, or how pentosan interacts with joints that might have mild-moderate OA. Notably, a similar study using pentosan and hyaluronic acid was inconclusive and demonstrated no improvement with treatment.  So there is still plenty of room for skepticism.  However, if the proposed relationship between increased synovial fluid and cartilage degeneration in osteoarthritis is correct (an extremely reasonable and supported assumption), and pentosan really does decrease synovial fluid and help decrease cartilage damage, then it seems reasonable that pentosan may help prevent or mitigate osteoarthritis (by mitigating cartilage damage and preventing the forces that result in increased synovial fluid).

There are still lots of “ifs” here.  But I’ll definitely be talking to my vet about pentosan in the coming weeks.

shut up and take my money