Koper Equine

It’s common to hear people talk about muscles in aesthetic terms — “well-defined,” “bulky,” “flat,” “perfectly proportioned.” Yet muscles don’t exist to please the human eye. They exist to move joints, stabilize skeletons, and transmit force efficiently. The real “ideal” muscle is not the one that looks the prettiest on a diagram or conforms to a human’s mental picture of perfection. It’s the one that best supports the body’s actual work.

Evolution Designs for Function, Not Appearance

Every muscle has evolved within a web of biomechanics, neurology, and tissue economy. Fiber type distribution, pennation angle, thickness, range of motion, tendon length, fascial attachments, and ability to perform comfortably all reflect the job the muscle is asked to do.  Form will follow use, and the muscle will develop to support that 

Form Follows Load

When an animal trains or recovers from an injury, its muscles remodel to match the loads and movements it experiences. A racehorse’s gluteals develop dense, spring-like fibers for propulsion; a dressage horse’s longissimus dorsi thickens for sustained core stability. Neither pattern is “better” in isolation. The form reflects the specific function the horse needs. Trying to “sculpt” a different look may actually reduce efficiency or increase injury risk if it conflicts with the animal’s movement demands.

Note: A bodybuilder has big muscles but limited mobility and agility. A cross country runner has light agile muscles, designed to optimize their ability to cross ground and tackle obstacles with the least extra weight possible. After a tough event they likely look even more defined and dry, as their muscles have temporarily shed excess water and glycogen during exertion. The vascularity and tone you see isn’t just from “muscle gain,” but from the body’s adaptive response to sustained endurance effort — increased circulation, fascial tension, and neuromuscular tone.

Where the bodybuilder’s muscles are built for power output in short bursts, the cross-country runner’s are conditioned for efficiency — long, elastic, fascially-integrated lines that emphasize recoil, rhythm, and oxygen economy over brute strength. Their definition after an event reflects a system that’s just been finely tuned through stress — fascia tightened, fluids redistributed, and every fiber optimized for recovery and readiness.

The Trap of Human Aesthetics

Because humans are visual, we often assume “defined” equals “strong” or “flat” equals “weak” or that dip is “bad”. Evaluating muscle by appearance alone can lead to misguided training, feeding, or even bodywork.

A More Functional Lens

Instead of asking “Does this muscle look the way I think it should?” a better question is “Does this muscle do what it’s supposed to do?” That shift requires looking at performance markers: range of motion, endurance, symmetry in movement, dexterity, response to palpation, and recovery after work. This approach aligns training and therapy with the horse’s actual biomechanical needs, not our aesthetic preferences.

Practical Implications for Trainers and Therapists

• Assess movement first, shape second. Watch how the horse moves under load before judging its musculature.
• Condition for tasks, not for looks. Build exercises that improve the functional role of each muscle group.
• Respect individual variation. Breed, conformation, and history all create legitimate differences in muscle form.
• Educate owners. Help them see that a “less perfect”-looking muscle can still be highly efficient, functional and healthy.

The Real “Ideal”

When we let function dictate form, the “ideal” becomes dynamic: a muscle built exactly for the job at hand, resilient against injury, and integrated with the rest of the body. That’s far more valuable than a textbook shape or trendy “ideal.”

Thank you to Kylie Cahoon Eventing for these amazing photos!