Can protective boots really support joints and tendons?

by, Dr. David Marlin, Scientific and Equine Consultant

Many people apply boots to horses’ legs too tightly. This may be for fear that they will come undone or move, in which case they are likely either of poor design or a poor fit. However, people often say that they put them on tight to give support to the soft tissue structures such as the tendons or the joints, and these claims are even seen in the marketing literature and adverts of some companies. There is minimal information to suggest that boots designed for training and competing provide support for soft tissues or joints. A boot may reduce the range of motion (flexibility) of a joint for example, but this risks moving the load from one structure to another and this may not be beneficial. Tight boots can also result in discomfort and rubbing injury. Just try strapping your ankle tightly over the Achilles tendon area and then go for a run! You will feel pain in the Achilles with each stride and you will modify how you run. Afterwards you may developing swelling and significant pain around the Achilles and also have pain in your knees and hips. It’s not only boots; it’s not uncommon to see bandages applied over-tightly in the belief that this offers “support” for joints and tendons. So appropriately designed boots have the potential to protect the lower leg against both concussive and cutting type injuries caused by hitting objects such as fences or from interference from other limbs. But there are a number of potential downsides to using boots which should be considered and this may help when trying to decide whether to use boots or not or which boots to use.

Quote from Dr Rachel Murray, Orthopaedic Clinician and Researcher at the Animal Health Trust Newmarket: “There is minimal information to suggest that boots provide support for soft tissue or osseous structures. The anatomy of the limb has the digital flexor muscles located proximally. This means it is difficult to provide support for the entire limb taking account of the muscle body. If a boot is used to reduce the flexibility of the limb, then there is a risk of load moving from one structure to another that has not been adapted to experiencing this load magnitude or direction.”

The weight of boots

Firstly, any weight added on to a horse will require an increased effort on the part of the horse to move that weight. This is of course true of a rider and tack. However, kilo for kilo, weight placed on the end of the limbs will have a greater impact than weight carried in the saddle area. The reason for this is that the limbs are moving faster than the main body. The need to be able to accelerate the limbs quickly explains why they are so light when compared with the rest of the body. Animals with big heavy legs cannot move them as fast. This is also why there is not much on the lower legs other than bone, some tendons and a small amount of muscle. All unnecessary weight has been “removed”. Any weight added requires more energy to be put in to get the leg moving and more energy to stop it and make it swing back again. Thus, adding small amounts of weight to the end of the leg in the form of a boot increases the effort the horse must put in to run. It is possible to measure the difference in energy to run between a horse wearing ordinary steel shoes (~260g each shoe) and the same horse wearing aluminium racing plates (around 80g per shoe), a difference of only 180g per shoe. In addition, not only can weight increase energy needed for exercise it can also alter the way the horse actually moves its legs (i.e. its gait). Some of the cross-country boots on the market for example weigh as little as 130g each whilst others are over double this. We should also take into account the potential for boots or bandages to absorb water when in use. Boots that weigh only around 200g each when dry may well be able to hold 100-200ml of water and as 1ml of water weighs 1g, this could double the weight of the boots if the horse was exercising in the rain, on wet grass or going through water. And the weight of the boots is also likely to increase if they do not allow sweat to evaporate and it gets absorbed by the boots.

Restriction of movement

The next issue relates to restriction of movement. If boots are constructed of inflexible (i.e. stiff) material or if boots are applied too tightly, they have the potential to restrict joint movement. This can lead to abnormal loading or patterns of movement with an increased risk of injury. There are relatively few scientific studies in this area but Kicker et al. (2004) published a paper in the Equine Veterinary Journal in which they looked at 3 “support” boots and 1 “protective” boot. At walk, 2 of the support boots restricted the range of movement of the fetlock joint, whilst at trot all 4 boots reduced maximum extension. An undergraduate BSc student study at Hartpury college by Jadine Birchall also seems to support these findings. The average range of movement of the fetlock joint in five horses during walk, trot and canter exercise was 42° (degrees) without a boot and only 36° with a boot. Remember that restriction of movement may cause discomfort and injury.

Trapping of material between the skin and the boot

Materials such as stones, twigs, sand, arena surface, mud, etc can become trapped between boots and the skin leading to abrasion and infection.

Restriction of blood supply

Tight boots and bandages can restrict blood flow in superficial blood vessels leading to pain and tissue damage.

Insulation and heating

The next issue with boot and bandage use during exercise relates to heating. Tendons are elastic structures and as they are repeatedly loaded/stretched (when the limb is on the ground) and unloaded (when the limb is in the air), they generate heat. Some work at the University of Bristol showed that the temperature inside the tendons of horses galloping without boots on could reach 45°C, second only in the body to muscle temperatures. The tendon temperatures are very high not only because of heat production within the tendons but because tendons have a relatively poor blood supply, which in any other tissue would help remove heat. In 1997 the same group published the results of a scientific study in which they showed that tendon cells in a test-tube were sensitive to heating. When the tendon cells were heated for 10 minutes at 45°C, around 10% died, but when they were heated to 48°C for 10 minutes then around 80% died. These results were also confirmed by a more recent study of equine tendon cells in Japan. This study also showed that the higher the temperature, the more tendon cells that died and furthermore, showed that inflammatory mediators were released after heating. Inflammatory mediators are chemicals and hormones within the body that cause inflammation (heat, swelling, pain) and tissue damage. If tendon core (central) temperatures can reach 45°C during a few minutes galloping without boots, it is almost certain that they will get even hotter when boots are being worn. It would therefore seem important to make sure boots are used only during the period of actual exercise and not left on for long periods when the horse is not active, especially after exercise. Removing boots soon after exercise and cooling the legs would also seem to be advisable.

Sweating and skin health

The fact that the lower leg gets hot during exercise and even hotter when boots are used presents another potential problem: sweating. When boots are removed the leg underneath is often very wet from sweat. When skin is in contact with moisture for a long time it becomes hyper-hydrated; this is the effect you see if you stay in the bath for too long. Wet skin cannot “breathe” normally, and it becomes more permeable allowing greater absorption of anything on the skin. Wet skin is also more susceptible to mechanical damage, with an increased risk of abrasions and grazing. Finally, wet skin is also more susceptible to bacterial or fungal attack and hence a potentially increased risk of conditions such as mud fever, caused by the bacterium Dermatophilus congolensis.

Summary

Riders should weigh up the pros and cons of using leg protection on horses. Different types of leg-wear give different protection. For example, bandages will clearly not offer the same protection as a cross-country boot. In addition, the level of protection offered by the same type of boot from different manufacturers can vary dramatically. Unfortunately, at this time there are no universal standards for equine leg protection as there is for example for hats or body protectors. It is also not possible to judge the effectiveness of boots based on appearance, price or advertising claims. At present, the best advice is probably to look for a light boot that is flexible, allows air to circulate and sweat to evaporate, that is not too absorbent and ask the manufacturer what form of testing for concussion and penetration protection that they undertake.

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Sleighing Safety - Especially For The First Time

Sleighing looks very much like pulling a wheeled vehicle but there are crucial differences. It’s not unusual to find this out a little too late! ~ Have experienced help with you the 1st time you hook a horse to a sleigh! ~ 

Not necessarily in order of importance: 

1. Use a kicking strap. Wear a helmet. Should be self explanatory!

2. A Horse's metabolism functions most efficiently at about 23 degrees, so all systems are firing well when you are sleighing. This translates into quicker reaction time on their part. The horse you drive calmly and relaxed in July may be a lot sharper and fresher in December. For the first time hooking, if possible, drive or ride your horse indoors or ride them outside before you hook them to a sleigh and assess their energy level and focus. Best for the 1st time that they be a little tired and the session rather short and uneventful. 

3. The drivers and handlers will not be as nimble dressed in heavy boots, thick gloves, and bulkier clothing as they would be in July, dressed in shorts, a t-shirt, sneakers and regular driving gloves. Think about this when you dress for hooking the first time. Reins tend to get a little slipperier when your gloves are cold and may have a little snow on them. I like to use textured reins for sleighing to improve my grip. I find smooth, synthetic reins get quite slippery with a little snow in the air. Leather reins work well too. Your regular driving reins may be a little short for the sleigh as you will tend to sit further and lower behind your horse. 

4. The footing is slippery and may be deep....for both horse and handlers. This affects your ability to move around the horse if things start to escalate towards trouble. Best to have extra traction  on your horse’s feet for sleighing. Discuss this with your farrier as this is one of the biggest compromise situations in shoeing. You want extra traction for your horse when you sleigh, but you may only sleigh once or twice a month. Do you want your horse to wear traction 24/7 just for this one time work? OTOH, you don't want him slipping and hurting himself when he does work. Screw calks may help with the flexibility of your options. Snowball pads can really help too. 

5. Seating in sleighs is generally lower for everyone than wheeled vehicles to provide a lower center of gravity for reducing "upsets". But this reduces your field of vision and makes getting OUT of the vehicle quickly a little more difficult. HOWEVER: the 1st time you hook, it is best to get in the sleigh before moving off than it is to try to walk beside/behind the horse while he is hooked. If he starts to run off, you will not be able to run with him in your heavy boots thru deep and slippery snow. 

6. Sleigh runners will often stick/freeze to the ground before you get into the sleigh after you have your horse hooked. He may not be used to the extra effort required to break it lose, or to the sounds the runners will make on ice and snow. After you have him hooked, before you get in, have a header holding the horse and break the runners free by moving the sleigh, then get in. Start off slightly on the diagonal; this will also help break the runners free. A little candle wax on the runners helps with this. Rust tends to form on them when not being used. Best to get this off first. Dragging it for a short distance on pavement, gravel or thru road sand will do this pretty quickly. 

7. Sleighs don't go backwards very well. Carry a whip. For the 1st hooking, put a halter with a lead attached on over the bridle and have a helper up front holding the lead. 

8. Turning is different than with a wheeled vehicle and generally requires bigger, sweeping arcs. Crusty snow is more hazardous when turning. For the 1st hooking, don't try it in a small enclosed area where you have to be constantly turning. Drive in a more or less level field, although I once hooked Morgan mare that I later found out had gone over a waterfall in a cart. She took off with me in the sleigh. Fortunately I was at the bottom of a hill and I just pointed her up the hill in about a foot and a half of powder snow...about half way up the hill she started to tire out but I pushed her on all they way to the top...she never bolted off with me again. I got lucky. 

9. Sleigh bells are fun but your horse first needs to get used to wearing them. Hang them on his stall door for a while so he gets used to the sound. Ask him to wear them while in his stall or being ridden or driven before you hook him to a sleigh. And keep it simple: don't use them the 1st time you hook to a sleigh. Your horse will have more than enough to deal with. 

10. Plan your route in advance. There are things hidden under the snow and the uneven footing can affect the confidence of the horse. Traction devices on the horse's feet obviously improve the security of his footing but they don't help when they stumble over something buried in the snow. The first few times you hook a horse new to sleighing, know for sure what lies underneath in your way. You can't turn 180 degrees very easily in a narrow road. Don't get trapped having to cross areas without any snow, like plowed pavement or plowed dirt roads. If your horse is experienced he may cross these short distances ok, but don't try it the first time out.

11. Snow conditions are not always the best for sleighing. Deep powder is wonderful, but a little tiring on the horse; packed but not icy snow makes the job a lot easier; Ice crusted, deeper footing is dangerous when it comes to turning the runners and very hard on the horse breaking thru and working against the crust; heavy wet snow makes pulling harder than light fluffy snow. The first time you hook, try for several inches of light snow or nicely packed but not icy footing. 

12. Your horse may get tired faster than he did in July with a wheeled vehicle. Depending on what you do with your horse, he may have lost some fitness from his peak competition condition by the time sleighing conditions arrive; the job of pulling may just be physically more demanding because of weather/footing conditions. 

13. Very cold air may be detrimental to your horse's lungs....not so such because of its temperature, but because it is so dry. Horses work hard pulling a sleigh and are apt to breath very deeply, pulling very dry, cold air deep into their lungs. I have never had a problem with this that I am aware of but I can see how a horse could get hurt. OTOH, when it’s very very cold, it's not the best time to be out there sleighing anyway. Don't pick the coldest day of the year to hook your horse for the first time. For more on airway damage from cold dry air see: https://thehorse.com/128397/cold-air-and-lung-health/ 

14. You are right to be concerned about the condition of your old sleigh. Dry rot can hide in critical places, especially under shaft wraps. Have someone who knows what they are doing look your sleigh over. You don't want to discover a weak spot while driving. -------------------------------------- 

Note from the Author: If you have *any* questions, suggestions or comments on this material,  please do not hesitate to contact me. 

Jeffrey B. Morse 

Green Meads Farm 

236 Perry Peak Road Richmond, MA 01254

 413.822.9462 greenmeads@gmail.com   www.greenmeads.com 

Accepting all levels and breeds of Horses and Ponies for training. Driving lessons with your equines or mine by appointment. Available for clinics nationwide.  

Green Meads Farm is located in the Berkshires of Massachusetts 35 miles east of Albany NY and 40 miles west of Springfield, MA Just 7 miles from Exit 1 on the Massachusetts Turnpike. We have a full size Dressage Arena, Hazards, Cones courses and miles of cross country routes.

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