The Road to the Tevis Cup, Post #10: Conditioning in deep sand

Fantazia and I have come to Paso Robles to stay with a friend whose stable has access to a beautiful long stretch of riverbed. I love where I live–I can ride out the back gate and up thousands of feet. But it’s mainly hard surfaces. The hillsides are soft, of course, but we sit and slide down them, and seek out firmer ground to climb when we can. Here I’ve got miles of deep flat sand to ride on.

Of course, I immediately wanted some feedback and advice from other endurance riders. Replies to my post on the AERC Facebook page were varied and advice (as usual in online fora) was abundant. They made me think about my own experience, do some research, and write this blog…

Table of Contents

The benefits of sand
Potential problems with sand
Factors other than deep sand that put soft tissue at risk
Why worry so much about conditioning in deep sand…
Suggestions for conditioning in deep sand
Resources

The benefits of sand

Sand surfaces, especially if deep, provide a fantastic workout. The horse has to use more muscle to propel itself… Doubt it? Go for a run, or even a walk, in deep sand. Remember the last time you went to a beach where you had to walk across the dunes to get to the wet sand? Right. It’s just as difficult for horses. A little sand goes a long way. Riding in sand is a great cardiovascular workout for the horse that strengthens lots of muscle that is used less when moving on harder surfaces.

Because it is hard work, deep sand can be a blessing with green, fractious, and/or fresh horses. It’s a lot more effort to be naughty or overly playful, and if the rider does fall off, it’s a soft landing. Been there, done that. Many of the trainers I galloped for in Madrid started their babies on the deep sand inner track, and kept them there until their brains and tendons were ready for a faster surface.

Sand–unless hard and wet–is also easy on hard tissue–bone, hooves and well as rider bodies. So horses with hard tissue lesions tend to be happy in soft sand, and green, unconditioned horses are unlikely to get hard tissue injuries.

Potential problems with sand

The one way hard tissue injuries can happen in deep sand is interfering. Because horses have to make a bigger effort to pull their feet out and forward, they are more likely to knock one leg with another hoof… Especially if they get to playing or being naughty.

It’s also possible for something hidden in the sand to cause an injury. If you are riding on public land, be careful for bottles, wires, and other trash. Even sticks or rocks can be a problem.

By far the greater danger, at least to hear everyone tell, is soft tissue injury. Whereas hard surfaces augment concussive force and increase the danger of hard tissue injury, soft surfaces require more elasticity from and put more strain on soft tissues, such as tendons and suspensory ligaments. (An easy-to-read short explanation.) I did a quick search for peer-reviewed research, and there is certainly scientific evidence that soft tissue works more on soft surfaces.

Some evidence that conditioning in deep sand puts soft tissue at risk

A study carried out with French trotting horses showed that conditioning in deep wet sand (compared with firm wet sand, in both cases on the beach) resulted in less impact–no surprise–and a more gradual weight loading (Crevier-Denoix et al., 2010). Deep wet sand also increased effort and propulsion, but it also puts more strain on the superficial digital flexor tendon. A separate study (probably from the same lab) compared wet and dry sand and asphalt, finding that impact forces were least on deep dry sand, but that stride efficiency was less–the horses had to work more for shorter strides (Chateau et al., 2010)

There are undoubtedly more relevant studies, but a quick search of articles citing the above papers produced nothing of interest. I wanted to find evidence of more than the mechanical aspects of load bearing.

But is conditioning deep sand really a problem?

Clearly, doing too much too soon can result in injury, but that is true in any footing. I have witnessed the starting of dozens of Thoroughbred babies at the Hipodromo de la Zarzuela in Madrid, which included some degree of work in a deep sand track. Some trainers worked them exclusively in the sand track for weeks, others alternated between deep sand and shallow sand tracks. This is purely observational and anecdotal, but! I never saw any evidence that horses worked more in deep sand had more soft tissue injuries.

Indeed, some researchers suggest that early conditioning of soft tissue protects it. Young horses’ are still growing, and their already constantly remodeling tissues are more able to respond and adapt to exercise (Dowling, Dart, Hodgson, & Smith, 2000; Smith & Schramme, 2003).****

****Yes, this is an argument to start horses earlier rather than later. See my post on Equine Bone Maturity

Factors other than deep sand that put soft tissue at risk

Age, surface

Besides age, exercise-related degeneration and surface put soft tissue–particularly tendons–at risk. Faster tracks–which are harder surfaces–result in more tendon injuries (Smith & Schramme, 2003). Uneven surfaces (e.g., holes, sudden transitions from hard to soft or vice versa) are frequent causes in unilateral soft tissue injury.

Exercise-induced stress causes breakdown of fibers which then must be given time to recover (see also Dahlgren, 2007). Because younger tissue remodels more easily, soft tissue in older horses will have more difficulty recovering and retaining elasticity (Dowling, et al., 2010).

Thus, although I have seen many yearlings and two-year-olds started in deep sand do well, it could be that riding an older horse in deep sand might result in tendon or ligament injury. If the problem is that older tissue does not remodel properly or as easily in response to stress (fiber breakdown due to exercise), then older horses would need greater recovery time as well.

Lack of sufficient recovery time (rest between workouts)

Once of the main causes of exercise-induced injury is failure to give the horse time to recover. Conditioning all tissue means breaking it down and allowing it to rebuild itself, stronger and more ready to withstand the exercise load (Dahlgren, 2007). This is true for all tissue, no matter what the surface (Clayton, 1992). The greater the effort (workload compared with prior routine), the more rest is needed before resuming training. During rest, the horse’s tissue repairs and rebuilds itself.

Fatigue

Tiredness combined with poor or unequal terrain is probably the most common cause of injury. (A short layperson article about soft tissue injury.) This is why it is so important to condition slowly and not to push your horse beyond its physical preparedness. Long slow distance (LSD) is an important aspect of Clayton’s (1991) Conditioning Sport Horses and the popular Go the Distance (Loving, 1997).

The fact that horses tire faster in deep sand should be taken into account when training. That said, fatigue and missteps can happen on any surface. I am not convinced that sand is a particular risk, especially if you listen to your horse. Many people suggested the use of a heart rate monitor when I raised the topic on the AERC Facebook page.

Hooves (shoeing, trimming)

Under-run and/or low heels are particularly likely to put more strain on tendons and ligaments (Oikawa & Kasashima, 2002). Otherwise misshapen or unequally shaped hooves can also contribute to injury (especially if not respecting the horse’s natural conformation, which must be worked with).

Genetics (conformation) and husbandry

Yes, genetics may predispose some horses to tendon (and presumably other soft tissue) injury. Here is another popular press article: Genetic link found in superficial digital flexor tendon injuries. Peer-reviewed research provides an abundance of evidence (e.g., Kuemmerle et al., 2016). Beyond tendon-specific genes, it is clear that poor conformation can cause unequal weight-bearing and injury to the tendon on the more loaded leg.

I don’t have time to look for academic evidence of an association between soft tissue injury and husbandry (nutrition and care) in horses. Companies that sell supplements and feed could probably do that work for us (but we’d have to take it with a grain of salt). For now, I’ll just express my inclination to believe that nutrition matters, as must care. Horses allowed to exercise in large fields of varied terrain from a young age are much more likely to have stressed their soft tissue (and therefore promoted strengthening and rebuilding). Pretty sure I have a citation in my Equine Bone Maturity post.

Why worry so much about conditioning in deep sand…

if so many other factors are at least as likely to cause soft tissue injury? It’s not only the experienced endurance riders who told me to be careful, it’s ME! I always slow down when I come upon deep footing (sand or mud), partly because the change in surface is always a risk for injury, and partly because I have never had the chance to train in deep sand. Not in my still-new experience with endurance. That’s precisely why I am here in Paso Robles now, to condition in deep sand.

I don’t know why everyone else worries, but I know where my assumptions came from: lameness checks and rehabilitating soft tissue injuries. When evaluating lameness, differences in gait between soft and hard surfaces is generally considered indicative of the type of injury. Hard tissue injuries are more easily seen on hard surfaces (cause more limp), whereas soft tissue injuries are more marked on soft surfaces. When rehabilitating a soft tissue injury, the horse should be kept on hard surfaces, with exercise increasing gradually and in a controlled manner.

From that I somehow got to “deep sand can cause soft tissue injury.”

Suggestions for conditioning in deep sand

Yes, I am coming to the conclusion that conditioning in sand, even if deep, has more pros than cons. That said, there are things you can do to minimize the dangers. (Many of these suggestions were offered in response to my post on the AERC Facebook group. Thanks to everyone!!)

1. Do it yourself first. Walk or, if you are a runner, run the deep sand route first. It’s not easy!
2. Go slow at first. Just like all conditioning, you don’t want to do more than your horse is ready for. Fatigue multiplies the risk of a misstep.
   • Start at a walk.
   • Some people suggest only trotting, some suggest cantering is easier.
   • In my experience on the track, horses find cantering easier. The horse uses its entire body to propel it up and forward at the canter, and can adjust the stride to the terrain. But this is a “feeling” on my part. Later I will look for evidence aka scientific research.
3. Monitor your horse’s exertion level. As mentioned above, a heart rate monitor can help. If you don’t use one, listen to your horse.
   • Remember that adrenaline makes it difficult for your horse to know its own fatigue level (and for you to therefore read it). So if your horse turns into a basketcase for any reason, or gets excited, it’s probably more tired than it lets on.
4. Know how deep the sand it. I asked what people considered deep, and got varied answers (past coronary bands, up to fetlocks…). It’s probably most important to know where the depth varies abruptly, because that is where injury is most likely to occur.

Resources

The academic papers cited in this blog are all linked above.

Conditioning Sport Horses is a complete version of Clayton (1992) cited above.

Go the Distance: an excellent book that emphasizes the importance of gradual conditioning–long slow distance–with a focus on endurance–by Nancy Loving.

Previous Road to Tevis posts:

Introducing Fantazia

Fantazia’s first three weeks

When I met Fantazia

How to calculate the grade of hills

The manure fork incident

Week 8 Training Update

Why the Tevis Cup?

What to do about a broken rein

Fantazia’s mysterious stocking up

Next Road to Tevis post:

The Road to the Tevis Cup, Post # 11: (Not) riding in smoke from wildfires