When I toyed with painting horses a few months back, I was serious about it; more than an whimsical fleeting infatuation anyways. I thought about how da Vinci studied musculature anatomy of humans in order to better his portrayal of the homo sapiens species. So I sought reference in the equine muscle diagrams.
Then I realized that wasn't the whole story. The well developed shoulder muscles and the bulky rump are tied to skinny, bony legs. Horses are unlike pigs or rhinos that position themselves on stubby appendages. Unless they are draft horses ? These bony legs help to personify the agility of the horse.
Not that long ago it was NBA playoff time. A lot of these elite athletes have skinny, bony legs. I would have guessed that they have bulging calf muscles. But then when I see some of these players wrapping their legs due to calf injuries I realized that what makes a person jump is more than the calf muscle. Amongst other things, it also requires the Achilles tendon pulling on the heel bone to springboard off the ground. There is a multiplying of amplitude advantage when one considers the foot as a lever, with the fulcrum set at the ankle. For everything to work, the muscle has to contract and the tendon has to pull. Of course there's no free lunch. The trade off for amplified flexion is that the muscles are required to contract harder and the ligament and tendon pulling tighter. A pulley system is just the opposite, it attains the mechanical advantage of lifting heavy weights by making us pull a lot of ropes. The picture I get in my head is the handbrake cable on my bicycle. When I squeeze my brake lever, a steel cable inside a plastic tube slides accordingly and pulls on the brake calipers. All hell breaks loose when the cable breaks, or when the plastic tubing gets split open or dislodged, allowing the cable to be squirrelly to the plastic conduit and not translate the force. Wrapping the leg helps to keep everything in place.
Then Halliburton of the Indiana Pacers suffered a season ending injury on the final game of the NBA playoffs. His cable broke and the lever could not be actuated. He was left face down on the court in total agony.
Horses have spindly looking legs for a different reason.
What one would normally consider or assume as the leg is actually the foot ( the metatarsal ). A very long foot. The front leg, or hand if you will, is represented by the long metacarpal. Horses have modified toes ( pastern bones ) and they are on their hoofs all the time. I suppose that's where the term "be on your toes" comes from.
