What are the tendons in the lower legs?

The tendons in the lower legs consist of tendon tissue, which are all individual cells that lie in line with each other and are held together by small bands. This provides the strength and elasticity of tendons.

Tendons are located on the surface, are not surrounded by muscle tissue, and are always "on". The horse uses these tendons both at rest and in motion. They have a function of stretching and pulling, which actually means that they can stretch when the horse is standing on the leg, but they retract when no pressure is applied. This stretching and pulling function depends on the number of healthy cells in the tendons that can collectively absorb the stretch.

Tendons mainly consist of proteins (amino acids) that provide the flexibility of the tendons. However, proteins can change their molecular structure. Think of the protein in an egg. When heated, it turns white and is much less flexible than before. Once heated and changed in structure, you can never get the protein back to its original form.

The disadvantage is that this also applies to tendons. The heating of proteins is called denaturation and occurs at 42 degrees Celsius. That is relatively quickly when you realize that the body temperature of a horse is around 37.4-38.0 degrees.

Back to the leg wraps

When we train a horse, we ensure that the whole body of the horse becomes warmer. This is necessary to warm up the muscles and for flexibility throughout the body.

However, in certain areas of the body, we do not want it to get too hot to prevent denaturation. Denaturation reduces the flexibility in the tendons, making it more likely for cells in the tendon to break, and a tendon injury is on the horizon.

The danger lies in the temperature under the leg wraps, which rises faster than you might think! During a normal training session, the temperature under leg wraps already rises to 43-44 degrees Celsius. Denaturation starts at 42 degrees Celsius, which means that even during a normal training session, denaturation occurs. You may not immediately notice anything because the entire tendon does not break at once. It's just a few cells that are affected, this is called microtrauma. In fact, they are a few small injuries that cannot be undone and they can no longer contribute functionally to the load capacity and tensile strength of the tendon.

When this happens too often, a tendon injury gradually occurs. That's why it's often not entirely clear where that injury is coming from.

Conclusion: be careful with leg wraps, especially in warm weather

Sometimes it is necessary to use leg wraps, for example, in cross country or other disciplines where there is a risk of trauma from external factors. Always be critical of the type of leg wrap you use, choose wraps that ventilate well. Do not use wraps just because they look nice or to complete the set, the damage from the heat underneath is irreversible! So also be especially careful with bandages and wraps with faux fur inside. The damage in a tendon is not repaired with tendon tissue, but with connective tissue, which provides less elasticity.