Page 24 - 2021 October Parker Co. 4-H Connection

Biomechanics of Breathing
King Equine Osteopathy

Did you know...?? That how a horse breathes during exercise depends on what gait they are in.
Horses physically expand and contract the chest when they are breathing at rest, at walk and trot, and perhaps most
noticeably when they are blowing hard after exercise.

When a horse is standing, walking or trotting, they must utilize their intercostal muscles (muscles between the ribs) and the
other accessory muscles of breathing to increase their respiratory rate. Like any muscle, these muscles will fatigue if they’re
not fit and healthy. Horses do not breathe by expanding and contracting their chests during the canter and gallop. During
canter and gallop all air movement comes from movement of the diaphragm and pressure from the movement of the
contents of the abdomen. At canter and gallop normal horses take one breath perfectly in time with one stride. This is
referred to as respiratory-locomotor coupling (refer to the images below).
As the horses’ front legs leave the ground and their weight is transferred onto the hind quarters, the abdominal contents
swing back towards the pelvis causing the lungs to inflate (inhalation, breathing in) as the diaphragm pulls back
simultaneously.
As the horses front legs stretch forward and make contact with the ground, their weight is transferred forward. In this phase
the abdominal contents swing forward towards the chest and shoulders, pushing against the diaphragm and forcing the air
back out of the lungs and causing exhalation (breathing out).
This means that your horse has no ability to increase or decrease its rate of breathing in canter and gallop.

Think about this when you do your fitness training! Imagine not being able to breathe faster as you get tired during exercise
and require more oxygen. Now is the time to start thinking about slowly building your horses fitness for the coming
competition season. Start slow and if you want to know how your horse is feeling, think about how you feel when you have to
go for a run when you’re not fit. It burns. You will feel it in your muscles and ALSO in your lungs.

Fun facts

Horses hold their breath when they jump.
Harness racers, because they compete only in trot/pacing, have to utilize all of their accessory muscles of breathing
during a race to allow them to get enough oxygen. After a race, this means that not only are their locomotor muscles
tired, but their breathing muscles are tired as well. They will typically take a much longer time to stop blowing after hard
exercise.
Gallopers do not have to use their accessory muscles of breathing to breathe during a race due to respiratory-locomotor
coupling. This means after a race they will blow for a little bit but, as the muscles they need to use for expansion and
contraction of the chest during rest, walk and trot haven’t been used during the race, these muscles are not fatigued and
can return the horse to its normal respiratory rate much faster.

24 PARKER COUNTY 4-H CONNECTION / OCTOBER