True engagement of the hindquarters starts with a tightening
of the abdominal muscles which work to tip the pelvis under, stretching and
tightening the dorsal ligaments as this happens. The back rises, the
hindquarters flex downward from the lumbo-sacral junction, and voila, a
horse with engaged back/haunches under himself.
This is a "good thing" if you want to do fast starts and quick turns (the
hind quarters work as a sort of coiled spring that compress, then shoot the
horse forward) As the horse lowers those hindquarters this way, he also
shifts his balance more onto his rear end, and less on his shoulders. This
makes it a "good thing" for going down hills (or climbing them).
Fine and good -- an athletic way to carry the body. Something all "good
horsemen" have striven to achieve for a very long time.
however, for gaited horses, when this position is achieved, there is a trade
off. The tighter the dorsal ligaments become, and the more "engaged" the
hindquarters become, the less elasticity there is in the back and the more
a horse is likely to trot rather than do one of the easy gaits. The easy
gaits require a looser use of the dorsal ligaments and more elastic use in
the back muscles than the trot does. You can engage the hindquarters
somewhat in a fox trot and still keep the gait, you can engage them very
slightly less than the fox trot in a running walk and still keep the gait,
but if you try to keep them consistently "tucked under" in a saddle rack or
stepped rack, you will not be able to do that and keep the gait. (not even
mentioning the step pace here). For both the saddle and true rack, the
horse's hind quarters need to flex up and down at the lumbo sacral junction,
and when they flex "up" the engagement of the hindquarters is impossible.
Also, to do these gaits, there needs to be a certain amount of slack in the
dorsal ligament system to accommodate that up and down flex ... without it,
no flex, no gait. Simple as that.
So, to me, it doesn't make a lot of sense to "engage more" with the
hindquarters on a horse that may be likely to be trotty -- on a pacey one,
you indeed *need* to bring the back and hindquarters more into a less
disengaged, more rounded position if you want to have an easy gait that is
NOT a pace. You can balance a gaited horse, or help him find his balance,
very well, and should! But you have to be careful how far you go in truly
engaging his hindquarters and back ... Remember that the idea of engagement
was invented for trotting horses by people who though gaited horses were
defective. There was a reason for their thoughts! We know they are just
"different" not defective trotting horses ... but if your end goal in riding
was a horse that worked entirely and strongly from his hindquarters in total
collection/engagement --- the gaited horse would indeed be defective, *IF*
you were also trying to keep him in one of the easy gaits.
Of course, if you are doing a lot of hill work you do indeed want to bring
them into some engagement -- and balance, so that they can go down hill
without falling on their noses or spraining their shoulders. But, you do
that at a walk, not in the easy gait ... or at least, you do if you want to
survive the descent!
The hindquarters and back *define* whether the horse is
collected or not. Without that raising/lowering going on, the horse is not
in collection. And indeed, it *is* desirable, for more than a few seconds,
in any horse, if he is expected to work off his hindquarters for balance. I
want a horse to stay in that position going down a steep hill, for instance,
because it prevents him from tipping forward on his nose and falling. And of
course, if I am chasing a cow down a steep hill, I want that position
sustained for two reasons -- to prevent the horse from falling, and to allow
him to quickly change direction after the cow if the stupid bovine suddenly
decides to dash off to one side. It is indeed sustainable for long
periods -- but only if the horse is in condition to do so. Obviously a horse
fresh out of the pasture who has just learned to carry a rider without
tripping over his own legs will not be able to do this for very long!
The back doesn't really undulate much at
speeds over a slow walk (it can't, if it did the spiny processes would grind
themselves to bits) What I meant is that the looser dorsal ligaments (which
allow the back to sag downward somewhat) are complimented in the easy gaits
by a certain tautness in the back muscles that help support the spine to
keep it from grinding itself up, but that the two sides of the back work
differently in the easy gaits than they do in a trot.
In the trot, one side
stretches, the other contracts (very simplistic, it is a LOT more
complicated than this) but in an easy gait, esp the rack or step pace, this
doesn't happen -- instead the back is relatively elastic on both sides. IN
the rack (and fox trot) the reason the tail is a "shaky tail" has more to do
with the action of the hind legs and the up and down "bounce" to the
hindquarters caused by the action of the hocks than the extension of the
motion of the spine. In an ordinary walk, where the spine does indeed
undulate, the tail does not move this way, nor does it do so in a flat walk
or running walk. Different use of the hind legs in those gaits.
In the rack (tolt) the hind end works up and down on the "hinge" of
the lumbo sacral junction. It is not held in a sustained lowered position,
and there is no stretch in the dorsal ligament system due to this.
The swing of the back in the trot is not really connected to
whether or not the dorsal ligament is stretched etc ... more like the belly
getting out of the way of the advancing hind leg in practice. (easier to
move if that belly is alternately out of the way of the leg moving forward).
The spine is really NOT held rigidly in a horse with good
schwung -- the dorsal ligament may be tighter, but the back muscles (l.
dorsii) are actually MORE elastic than in a horse that is doing a rack or
step pace. There are two systems working here -- ligaments and muscles.
They compliment one another. The up and down motion in the rack is not
really due to being "tucked" under in the hindquarters in the same way a
totally collected trotting horse would be.
There is no point in which the spine is flexed upward
as it would be in a horse with truly engaged hindquarters. If you look at
pictures of racking horses, you will NOT see a rounded/raised spine in the
The spine is held downward by those tighter back muscles that
become more involved as the dorsal ligaments go more slack. There is no real
big push forward, there is more of a jump forward over the front leg in
The lack of this really strong engagement is given away by the
signature upward flip of the hind hoof in horses that are racking. If that
energy was being put to use to thrust the horse forward, the hoof would not
flip in the same way. Has to do with release of tension in the tendons in
the hind leg, which also play a huge roll in engagement (or lack thereof).
The hind leg can come WAY forward without any engagement of the
hindquarters, just look at the typical big lick TWH. So, no, it is not
going to be the same thing as true engagement of the hindquarters no matter
how far the hind leg is reaching forward .. if the back is not
raised/rounded and the hindquarters are not at least slightly lowered from
the lumbo sacral junction, there is not true engagement, either.
As an example, think of Groucho Marx walk (this image borrowed from Deb
He sort of squatted down, with his fanny in the air, and took enormous steps
while flicking his cigar. Hollow back (human) still lots of reach in his
legs for those steps. This is the ultimate image for me of how a BL horse
I think it would be better to forget about how long or short the step is
from the hind leg (or even how far it is under the body) and look at the
entire horse as he moves (video, slow motion) to see what is happening in
the back. Failing that, ride them bareback and be honest about what you feel
under your seat.