Re: Heart Rate

[Jerald Thiessen <thiesj@tdbank.ca>]

Kim
Thank you for replying to my post. We were trotting at the speed my horse
(saddlebred /arab cross) loves to travel. I have put over 10,000 miles(
approx. 2000 in competition) on him over the last 8 years. He will pick the
trot and go ,often passing horses which are cantering. That is where this
discussion came from. Both myself and  my friends horses were traveling about
15 miles an hour at a trot ( Zeus can easily trot over 20 miles an hour, its
the saddlebred in him) and we were trying to determine which gait is more
efficient for endurance. My friend suggested that he was going to condition
more at the canter because his horse's heart rate was actually lower while
cantering at that speed. I have to agree that Zeus also has a lower rate at
the canter. I do know that he can trot the majority of a race and recover
faster than if I force him to canter the same distance even though his heart
rate while traveling at the canter is lower.
While I agree with the logic that I should being cantering because his heart
rate is lower, I also know that I can get more mileage out of him on a given
day at the trot.  He has been conditioned to the point where I have done a 12
mile medium canter on him without causing him undo stress as he pulsed down in
under 10 minutes. I believe my horse is well conditioned at both gaits, so
bottom line, at an endurance pace which gait do most of you find more
efficient? Does anyone else's horse have a higher pulse at the trot than at
the canter or is it something that only happens in Canada?

Jerald

Kim wrote:

> On Wed, 23 Sep 1998 12:04:02 -0600, Jerald Thiessen <thiesj@tdbank.ca>
> wrote:
>
> > I was having a discussion the other day on a training ride with a friend
> > and we started talking about stress on a horses legs and cardiovascular
> > systems. I  believe that trotting puts more stress on the legs but was
> > easier on the cardiovascular system.My friend disagreed with me and
> > raised a very good point. If trotting is easier on the cardiovascular
> > system then why  does the heart rate go up when I pull the horse from a
> > canter(120bpm) to  a trot (140bpm) and vice a versus when trotting if
> > we go to a canter the heart rate drops.
>
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=
>
> Every gait has a point, or speed, which delivers the most work for the
> least amount of oxygen (which would determine cardiac output).  Each
> gait has a certain speed which uses the least amount of oxygen compared
> to other speeds at that -same- gait.  You could push the horse to a
> faster speed at that gait, but he would require more oxygen to maintain
> that speed.  And, on the other end of the spectrum, you could slow a
> horse down at the same gait, and he would require more oxygen because he
> is not working efficiently --- he would require more oxygen to move 1
> meter down the trail.
>
> So, each gait has it's own "optimal" speed, which requires the least
> amount of oxygen for the horse.  Endurance riders will find this speed
> after time --- this is the pace your horse tends to "settle" into during
> a consistant-speed conditioning ride.
>
> Now, if you compare the oxygen requirements at a trot to a canter AT THE
> SAME SPEED, one of these gaits is going to be very inefficent in oxygen
> use.  This depends on the particular horse and the speed which you are
> comparing.  Seems like in Jerald's example, the horse was moving faster
> than the "optimal" point for his trot, which increased his heart rate
> compared to the next step up, which was the canter.  Since the canter
> had a lower heart rate at the same speed, this speed was better suited
> for this gait (in terms of oxygen needs).  Horses, when left to their
> own devices, will automatically select the optimal gait for a particular
> speed --- it's just more comfortable for them.  But, humans ask them to
> collect a canter to a very slow speed, or preform an extended trot while
> showing, etc. where both are inefficient uses of oxygen for the horse.
> But, you usually won't find this occurring often with endurance horses
> for a long period of time ;-)
>
> Regarding forces applied by both gaits:
>
> The trot and the canter do not have a *huge* difference in the overall
> amount of force, but what is interesting is how individual legs receive
> this force.  Since the trot is *just about* symmetrical (two legs
> contact the ground at once, with just a split second difference), the
> horse does not experience a huge force "spike" when the initial hoof
> hits the ground. The second hoof takes up a good portion of that force
> as soon as it hits as well.
>
> The canter, on the other hand, does have an inital "spike" when the
> horse moves from suspension (in the air) to when the hind hoof hits the
> ground.  The timing between the first and second hoof contacting the
> ground is greater.  Also, measurements have shown that while the
> non-lead foreleg of the cantering horse recieves more force compared to
> the trot, the lead foreleg actually sees a reduction of about 20%.
>
> The gallop is a whole different story, and can generate a whole lot of
> force --- I'll stay out of that one since it usually is not the choice
> of gait for endurance riders :)
>
> If anyone needs the research references, just let me know.  Hope it
> helps!
>
> Kim (and the ground-poundin' Lee)