Last Updated on February 21, 2022 by Allison Price
Although the equine stafle is very similar to the human knee anatomically and physiologically it is more complicated and more stable. The patella and cruciate ligaments are used to connect the bone framework of the joint. However, horses have three patella ligaments and a larger quadriceps than humans. These additional ligaments are part of the unique biomechanics that enable horses to “lock” their knee caps and attain a deep resting position while standing up. This was an evolutionary advantage for prey animals.
The stifle can still be affected by arthritis. This is due to a slow wear and tear that occurs as a result of sports activity and/or more severe, traumatic soft tissue strains and tears. Because horses are more stable than humans, soft-tissue injuries such as cruciateligament tears or meniscal (fibrocartilage disks between the femurs and tibia), injuries are less common in horses. These problems can be serious and could end a horse’s athletic career.
Who is at Risk
The injury to the ligaments in the horse’s stifle is usually caused by a combination speed and rotation. Horses may make mistakes when they travel at speed, or are out of balance. Horses who try to load the stifle in an uneven manner can cause injury by straining the stabilizing structures. Horses that dressage, or perform at a slower pace than jumpers or eventers, can also be at risk for stifle injury. This is because their sport requires them to bend and rotate their upper bodies.
It’s not just equine athletes who are at risk. Any “pasture potato”, can sustain a stifle trauma from direct trauma. This includes kicks, slips or problems associated with poor footing in wet, muddy, or icy conditions. Stifle injuries are more common in weaker, less fit, and overweight horses. These horses are at higher risk due to insufficient abdominal and core muscle development, as well as a lack of conditioning and tone. Unbalanced loading and landing can increase the imbalanced forces on the body, and could lead to stifle injury.
Young horses are particularly vulnerable during growth spurts (periods with rapid bone and body mass development marked by uneven growth of different structures). Their ligaments can become tighter or looser depending on changing joint angles and bones. The stifle joint is made up of four bones and several ligaments. This area is often involved in growth-related issues. It can take some time for the slow-growing ligaments to catch up to the horse’s stifle bone development and for the quadriceps muscles to grow in strength and size.
Riders often report that horses who were previously free from problems now feel “weak behind” and “not connected.” They may also fall out of line more frequently, have trouble keeping their horses on the straight path, or make clicking or popping sounds. These growing horses may have a tendency to not keep a straight line downhill. In extreme cases, the horse may try to go downhill at an angle. These symptoms can sometimes be indicative of structural problems but are more often signs and symptoms of weakness.
Turnout and Stretching
You can protect your horse’s stifles from injury by doing progressive strengthening work. This is especially important if the area is already weaker because of conformation, lack or conditioning, or any other factors. Before you start a strengthening program, consult your veterinarian if your horse is clearly lame, or if any joint feels tender, tender, or painful. The more you can condition him to be able to tolerate a fitness program, the less injuries he will likely suffer. This is especially true of the stifle. There are two main ways to make it stronger:
1. You should increase your horse’s daily movement. Try to place him on pasture that is rolling and has companions. Horses are more active when they are surrounded by other horses. Spread hay in multiple piles to encourage your horse’s active eating habits.
2. Stretching exercises should be done safely and with care. These exercises are best performed on a level surface with good footing. It is often necessary to have someone help your horse, especially when it is first haltered. Each exercise will require you to lift your horse’s hindfoot off the ground. Then, stretch the muscles as directed until you feel some resistance. You can hold the stretch for as long as you like, or until your horse is comfortable with it. Then release. You can gradually increase his range of motion as he gets more comfortable with the stretching routine.
- Flex your hips and stifle by raising your horse’s hoof up and pushing it toward the middle of the body. This is the same motion that veterinarians use when they do a hockflexion test. Next, lift the hoof and flex the hock. Then pull the leg away from the horse’s body.
- Move the hind hoof toward the back of your front leg, on the same side.
- Move the hoof forward, stretching the hind leg out in the same way you would for picking out the foot or a farrier would. This position will allow for a lot of extension if you apply slow pressure and let your horse relax.
A good-quality walking walk is a great way to get your horse moving and using his muscles. He must be balanced on one leg and push forward with his quadriceps. This will strengthen muscles and ligaments. Ask a dressage instructor, or any other equine professional for help in getting your horse properly rounded in the frame and correctly positioning his hind legs under his body. It may take time, as weak horses will have trouble achieving a good frame. However, consistent, slow, steady work will yield long-lasting results.
Step 1: I raise the hoof forward and upwards to flex the horse’s hips and stifle. You can help your horse balance by flexing his joints. Keep the horse’s lower leg in line with the midline, and keep the weight of the horse centered over the support leg. For the first time, each stretch should be held for between 10 and 20 seconds. You can gradually increase the horse’s ability to move freely as he becomes more familiar with the stretching routine.
Step 2: Keep the hoof elevated and the hock flexed. Push the point of your hock towards the midline, while pulling the foot laterally or away from the midline. This rotates the stifle, stresses the ligaments, and eventually, strengthens them. This can be reversed by pulling the point of your hock outwards and pushing the hoof medially (or inward) to rotate the stifle. It also serves to strengthen the lateral or outward supporting structures.
Photos courtesy (c) KLM Equine
You can also strengthen your stifle by doing exercises on the ground or in the saddle.
- Hold your haltered horse by a helper a few feet away, with his tail in his hands. Pull the tail towards you until your horse resists the pressure. As he resists your pull, you will see his back, abdominal muscles, and most importantly, his quadriceps muscle tighten. Tend to the pressure for 10-15 seconds, then release. This exercise can be repeated 10 times per side.
- Hand-walk your horse on inclines. He should walk slowly, keep straight lines and not allow him to swing his hips to one side or the other. Balanced use of the stifles is required for this. You can stop your horse periodically, as this increases the force on the patella ligaments and quadriceps. Then walk away again. This exercise is particularly valuable as the horse can concentrate on his own movement and balance without having to compensate for the rider’s weight or position. An improper exercise can be damaging and render strength and conditioning efforts nearly useless. Keep the exercises simple and do them well.
As the horse circles around, a gentle incline helps to strengthen and isolate the muscles and ligaments. You will need to find a spot in the pasture where the terrain is flat and becomes a hill. Standing at the top of the terrain, longe your horse so that half of the circle is on the flat ground and half on the hill. Your horse’s quadriceps muscles will be used to climb the hill. These muscles support the stifle. These muscles will strengthen their ligamentous connections to the bones of the stifle joints by performing an incline or unbalanced footing exercise.
Your horse’s inner quadriceps muscles will be used as he goes down the hill. These muscles are hard to target so people must use side-leg pull movements to strengthen them. Horses can tolerate inline longeing and it has the added benefit of helping them achieve balance. Your horse should keep a steady pace and not lean to the outside or inside. These photos show our model, who is calm and skilled at longeing. He is wearing a halter. If your horse is more energetic or animated, plan to use a bridle, longeing cavesson or other supporting/controlling aides.
Photo courtesy (c) KLM Equine
- Focus on the transitions: walk to trot, trot-to-canter, walk-to-canter, etc. Smooth and balanced movements are good for building muscle, ligaments, and improving motion.
- Instead of riding in straight lines in open fields or pastures, create shallow serpentines to require your horse’s flexibility and use his inner and outer leg muscles, primarily the quadriceps.
- You can ride on deep sand beaches and other soft surfaces if you have it. If you work too hard on these surfaces, it can lead to other injuries. Pay close attention to the following advice about gradually building up. Concentrate on movements that use the medial or lateral quadriceps muscles as your horse gains strength, such as spirals and circles.
Annelise Stone rides Assassin’s Shooter in a steady trot. She makes sure he is engaged behind him and pushes with his hind legs so he can lift his back. This will build muscle and strengthen the ligaments in the stifle.
Photo courtesy (c) KLM Equine
Riders are more likely to do too much strength training and give up too soon. It doesn’t matter what exercise you choose, it is important to take things slowly and do each step in a systematic way. Start slowly, with easy sessions, and don’t increase the intensity or duration of your exercise.
If you begin with 15 minutes of longeing flat ground, including warm-up, cool-down, and multiple changes in direction, then repeat the program in your next session. You can increase the time by adding three to five minutes to your next session if your horse is able to do this. You can increase the time for seven to ten sessions, until you have a workout that lasts 30 minutes or more. You can shorten a session or add hill work ( increase intensity) to make it more efficient. For example, you could do 10 minutes flat lungeing followed by eight minutes of walking up hills. You can simply return to the same lower intensity level that you were previously doing and continue to work on your horse for a while before increasing intensity.
These strength-training sessions can be incorporated into your weekly training program. It should include at least three days of exercise per semaine, but preferably four to five. Keep an eye on each session, and use it to time the session. Don’t overwork if the session is going well. Keep track of the program and keep track of its duration and intensity. You can use this information to track progress and to decide when to push the training and when to let your horse rest. Both of these are crucial for achieving better fitness.
You can strengthen your horse’s muscles and ligaments by providing patience, methodical training and attentiveness to the exercises. This will ensure a happier and healthier career.
Dr. Kenneth L. Marcella graduated from Cornell University’s New York State College of Veterinary Medicine. He has been treating sporthorses at all levels and disciplines for more than 30 years, including international competitors. Dr. Marcella served as a veterinary official at numerous events, including Olympic and World Equestrian Games national championships. He is currently a member of the selection committee for The United States Endurance Team.
Dr. Marcella holds a degree in English literature from Dartmouth College. He also coaches and plays hockey.