A strong topline is one of the most important indicators of a well-conditioned horse. In addition to being aesthetically pleasing and supporting performance, a good topline can protect your working horse from strain and injury.

Horses with strong topline muscles generate more power from their hind end, are less likely to develop back pain, and are at lower risk of hock arthritis. [1]

Building and maintaining a strong topline depends on a combination of genetics, proper nutrition, appropriate training and well-fitted tack. Feed a well-balanced diet that meets your horse’s protein and amino acid requirements.

Simple exercises and stretches can stimulate muscle development, improve your horse’s topline, and support improved mobility through old age.

Conditions such as lameness, polysaccharide store myopathy (PSSM) and pituitary pars intermedia dysfunction (PPID) can cause poor topline. If your horse is losing muscle or has trouble building topline, consult with your veterinarian and equine nutritionist.

What is the Horse’s Topline?

The horse’s topline is the area that runs from the withers along the back and loins, and down to the croup. The topline supports the suspended structure of the spine and sacroiliac area.

Think of your horse’s spine like a suspension bridge: their legs attach to either end of the bridge and your horse’s topline is the cable that strengthens the suspended roadbed, keeping it from sagging.

An unsupported spine is more susceptible to potentially painful and permanent damage. A strong topline keeps the spine protected and supported. [2]

Topline Muscles

The major muscles of the topline include:

  • Longissimus dorsi: The largest muscle in the equine back, it originates from the spinous processes (projections of the vertebrae) in the sacrum, lumbar and thoracic regions as well as the hip. The Longissimus dorsi stabilizes the spine and enables proper movement. This muscle supports the saddle and rider.
  • Latissimus dorsi: This muscle extends from the connective tissue between the thoracic vertebrae and croup, and attaches to the humerus (upper bone of the front leg). It functions to bring the leg backwards and to propel the horse forwards.
  • Trapezius: A flat, thin muscle in the wither region that extends from the neck to the shoulder blade, and from the shoulder to the thoracic vertebrae. It functions to move the shoulder blade (scapula) forwards and backwards.

Exercises to build topline will primarily target the longissimus dorsi but also involve the latissimus dorsi, trapezius and other smaller muscles such as the spinalis dorsi.

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Assessing Topline

The state of your horse’s topline can be evaluated visually and through palpation. The muscle should feel smooth and flat, and the horse’s body should appear well-rounded.

Excessive fat accumulation can make it difficult to assess the topline. Accurate body condition scoring should be combined with topline evaluation to get a more complete picture of the state of your horse’s body composition.

Horses that are losing fat mass may appear to be losing topline muscle. It is important to distinguish between fat and muscle when making training and nutrition decisions.

Body condition scoring (BCS) is conducted using the 1 – 9 point Henneke Scoring System, which that assesses fat deposition on the neck, withers, shoulder, ribs, rump and trailhead.

A score of 5 is considered ideal and appears as a smooth, level back with rounded withers and ribs that can be easily felt under slight fat covering.

Topline Evaluation Score

A Topline Evaluation Score (TES) can be used to assess topline status and to track changes over time: [11]

Grade Description Visual Cues
A Ideal
  • Muscles beside the withers and along the spine are full; vertebrae cannot be seen
  • Hip is full and stifle bones are defined
  • Horse is able to perform work that requires topline muscles