01/15/2026
Understanding the Longissimus Dorsi:
Why Your Horse's Back Depends On It!
If your horse struggles with topline development, saddle comfort, or back soreness, this muscle matters more than you think.
The longissimus dorsi is one of the most important muscles in your horse's body. While it has multiple points of origin and insertion, it essentially runs from the horse's pelvis, along either side of the spine, and extends forward toward the neck. It plays a major role in stabilizing the back and supporting the rider's weight during movement.
What does it do?
- Supports and stabilizes the spine while carrying a rider.
- Transfers power from the hind end forward (impulsion).
- Supports collection, balance, and overall posture.
- Allows controlled lateral movement through the back.
- Helps prevent hollowing and compensatory tension.
The list goes on...
Because of its location and workload, this muscle is commonly tight or sore. Contributing factors can include ill-fitting saddles, insufficient topline development, changes in training, and rider imbalance.
Signs of tension or discomfort can include:
- Sensitivity to grooming or palpation along the back.
- Hollowing when mounted.
- Resistance to the saddle or rider.
- Hesitation or resistance to moving forward, sometimes expressed through behaviors like head tossing, bucking, or rearing when forward movement is requested
- Difficulty bending or engaging evenly.
This is one of the first muscles I assess during every session, because understanding the back is the foundation of keeping your horse comfortable, willing, and performing their best.
Have you ever noticed any of these signs in your horse?
This is the first post in a series exploring key muscles that impact your horse’s comfort and performance.