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Thursday, 2 May, 2019

How to use Seaver jumping data in over-fences schooling

In a jumping training (over showjumping polls or cross country fences) Seaver girth – or girth sleeve – brings you a lot of information to estimate the effort provided by the horse and rate the technical work executed. When combined with the rider’s feelings and the trainer’s impressions these data will help you better organize and analyse your training sessions. In order to do that here are a few tips to understand and use jump indicators in your work.

Estimating the effort provided by the horse to preserve his health

Heart rate data, calories, time spent at each gait or average speed and distance covered can be used in addition to the duration to quantify the physical intensity of a training. For a jumping training other data can help you.

  • Number of jumps

First of all the numbers of jumps performed during the session is a relevant indicator. When we work over a gymnastic grid or a whole course we tend to lose count.

Yet it is very important to monitor it: even when you don’t jump very high, 40, 50 or even 70 repeated landings have a significant impact on the musculoskeletal system.

For instance on this screenshot taken out of the summary page we can see that a training with 44 jumps of an average height of 115cm already is a substantial effort. You shouldn’t want to repeat this kind of session every day or on the eve of a bigger effort.

We advise you to keep under 50 jumps per training, and in any case stay below 70-80 jumps per week. Obviously this also depends on the height of the fences: from cavaletti to 160cm jumps there is a huge gap!

  • Energy absorbed at landing

That’s why Seaver also provides the total landing impact energy. It is complementary data, and allows you to figure out how much effort the legs have concealed (especially the forelimbs). At the end of each jump a part of the mechanical energy due to movement is kept and re-used in forward displacement, but another part needs to be dissipated thanks to both the ground and the horse’s damping system.

Thus the heels spreading, the coffin bone sinking into the plantar cushion and the forelimbs tendons extending all contribute to cushion the horse’s weight. Obviously the ground quality plays a big part in reducing the forces involved; that’s why coatings too hard or too deep and uneven should be banned.

The higher and the stronger the horse jumps, the more vertical the landing is, and the bigger the taken impact is. For example on a standard 1m jump the landing energy absorbed will be around 0,8kJ. It will reach 2kJ on a 120cm jump, and above 3,5kJ with trajectories culminating at 140cm. These data obviously vary depending on the horse and the characteristics of each jump.

The summed data on the whole session is the one that provides an indication of the constraints imposed on the locomotor system. In a typical training you should aim to stay under 70kJ in total. On 12 to 15-fence courses of classes higher than 130cm you will often exceed this value. It is not a problem as long as you become aware of the intensity of the effort and adapt ground and after-course care. Try not to repeat too often these huge efforts in order to best preserve the physical capital of your athlete.

Detecting abnormalities to anticipate physical problems

  • Hindlimbs push symmetry

The hindlimbs push symmetry transmits information on the good health of the musculoskeletal system of the jumper. This grade indicates the level of left / right symmetry of the propulsion, ie he analyses the way your horse uses hiss back and hind limbs to propel himself over the fence. A perfect horse should get a 50% / 50% score over each fence: that means the horse exerts the same force on each of his legs when he takes off, and rises straight following a constant direction.

However, it is not uncommon to get a poorer score on some jumps in the session, without this being a concern. It can be the case with a shy horse worrying about the polls or something else, a spooky horse that changes direction right before the jump of a bad distance resulting in a strange jump. In these situations, the weak hind limb will change from one jump to another (the weak hind limb is the one that has the lowest percentage, the right one in this example).

The global grade, that can be found in the summary page, is the one that must be examined first. The farther you get away from the perfect 50/50 ratio and the more asymmetrical your horse is. Below a mean of 45% / 55% over 10 jumps or more you need to really focus on this parameter especially if that particular horse used to jump symmetrically. If the result repeats over several sessions it may be a good idea to have your horse checked by a vet or an osteopath. Discomfort or pain in the back or in a hind leg can often explain an asymmetrical push. Sometimes it can also come from a problem in a front leg or a shoulder: the horse anticipates and tries to diminish the pain to come when he lands by twisting over the fence. You need to detect this kind of issue as soon as possible as it usually allows a better care and therefore a quicker recovery. The more your horse jumps with his asymmetry and the more risk he has to worsen the problem, or compensate with his body and create other lesions.

  • Trot symmetrty

Obviously you can monitor the trot symmetry as an additional piece of information. Remember it is only calculated while your horse has been trotting on a straight line for at least 10s. Trot symmetry can highlight a weaker diagonal, but due to the sensor’s position it is more sensible to the forelimbs’ irregularities than the hind limbs’ even though a blocked back should also show. The push symmetry allows to isolate the jumping mechanics and focus on the hind limbs in these specific movements. To find out more about the trot symmetry feature, please read our article (https://seaverhorse.com/en/understanding-seavers-symmetry-feature/).

In some horses you can find an established jumping asymmetry that stays after the physical problem was solved. The asymmetry was created after a pain or a discomfort that has now disappeared, but the horse keeps showing it. It can and must be limited through specific work. Eventually a horse that jumps asymmetrically, even if he doesn’t have a physical problem, cannot build up muscle harmoniously and will therefore have more risks of injury than another. That’s why you should closely monitor the hind limbs push symmetry.

Modeling your trajectories to analyse faults and improve approach

Besides the "health" aspect, jump indicators also bring information on a more technical point of view about your jumps. You can detail them jump by jump and associate them with the fences. That way it gets easy to understand the situation and improve your next jumps.

  • Jump trajectory

First of all please remember that the sensor does not detect the fence but only the jump your horse realized. The measured jump height is thus that of the girth (or more precisely that of the device’s sensor), meaning the height of the middle of the horse’s sternum at the peak of the jump trajectory. Depending on horses and fences, and the forelimbs style, this height can be 20 to 50cm above the height of the fence. It can be even more than 80cm above with a green horse, a very generous one or in the case of an open water jump or a ditch. On that photo you can see a poll hanging 95cm from the ground (blue arrow). The measured height will be around 120cm because the sternum is around 25cm above the poll (red arrow). It doesn’t mean the horse cleared 120cm, because his legs were probably lower than that at some point. It just means that the sternum was at 120cm from the ground on its higher point. To find out more about this, please read our article about understanding Seaver's "Jump Height" feature (https://seaverhorse.com/en/understanding-seavers-jump-height-feature/).

The sensor cannot detect the relative position of the fence and the jumping trajectory either. With horses that are used to displacing their trajectories forward or backward, you can get a poll down even if the measured height is bigger than the fence. Such horses are still ascending or already descending over the poll (they place the peak of their trajectory before or after the top of the fence), or they can forget to lift a foot. In these situations you will need your rider’s feelings, the trainer’s eye and potentially a good video to understand what happened. In other cases, Seaver data are here to help you!

The first feature that is useful to monitor jump by jump is the jump trajectory composed of the height, spread and angle. On an oxer or a run and jump cross country fence the angle should be smaller than on a vertical jump of the same height, and the spread will be wider. Ideal values depends on the height of the fence, here are some examples. For a 110cm class, the measured jumps will typically be over 130cm. On vertical fences we will prefer angles bigger than 30° with a spread of around 250cm. On oxers the angles should get closer to 20° and the spreads may go over 400cm. The higher the fence, and the bigger the angle and the spread, with always a bigger angle on the vertical and a bigger spread on the oxer. We can reach almost 45° with 180cm heights on a 160cm vertical. On an open water jump or a very big run and jump cross country fence the spread can hit 6m.

The angle is a measurement of your horse’s vertically when he takes off. The bigger the angle is, and the more your horse rises up. The smaller, the more your horse leaps forward. For example for a horse that is slow in his forelimbs’ gesture and requires room in front of the fences, you should aim for bigger angles. A small angle requires a farther take-off place from the fence to clear the same height. The spread can be very useful to analyse grids and combinations. The place you land after the first element of a combination is fundamental to respect a striding count in a distance, in addition to the canter strides’ length between the jumps. A forelimb fault on the second element sometimes comes from a spread too big on the first one, in a flat jump.

  • Propulsion and take off speed

Propulsion and take-off speed show your horse’s reactivity and the power he develops in his jumps. Obviously the higher the jump the bigger the propulsion/push. It is also bigger on a vertical jump than over an oxer. Here are some typical values to better estimate your horse’s performance: on a 70cm cross rail (jump height around 95cm) the propulsion will be just above 1g. It will be around 1,3g on a 1m fence (jump height at 115cm) and about 1,5g for a 115cm fence (jump height more or less 140cm). It will exceed 1,8g on 150cm jumps (jump height 165cm).

Propulsion is expressed in “g”: it is the vertical acceleration of your horse at the start of ascending phase. 1g represents terrestrial gravity (9,81m/ s²). A horse’s push stays usually between 1 and 2g. More than on the value in itself, you should focus on its evolution. For the same horse and fence, a higher propulsion value indicates a very painstaking horse, but maybe he is investing himself too much in his effort. He is doing more than needed and increases the risk of injury. On the contrary a horse with a lower push value may be tired or undergoing a fall of form. It can also be a lazy horse that needs to be motivated to use more energy over the jumps.

Take-off speed is the vertical speed of your horse during ascending phase. It is not his speed on the ground before the jump, but his up speed in the air when he leaves the ground. It should be between 15km/h and 30km/h, and it can reach 40km/h with some horses. It gives you a good idea of your horse’s reactivity, and also a very good information for jump-off. It is an objective indicator for the very well-known phenomenon of the horse that “loses his time in the air”. A slow speed (between 10 and 20km/h) can indicate your horse is “on the brake”/ he is loosing a part of the power he gained in his canter, and is often jumping too high. That kind of horse will need more propulsion than any other to clear the fence, and will tire more quickly. On the contrary a high speed can be found with horses that rush into jumps and don’t take the time to properly jump. Gymnastic grids without the rider interfering can help to solve that issue.

  • Cadence in approach

Finally, there is no jump analysis without an approach analysis, in particular with the cadence in approach and its variation. Locomotion data will give you the average canter cadence of your horse on the flat during the session (usually between 90 and 110 strides/min). To find out more about it please consult our article about the cadence feature (https://seaverhorse.com/en/seavers-cadence-and-elevation-features/).

Usually when popping over fences you aim to keep your canter cadence stable. (Please note that we are talking about strides frequency, and not their amplitude.) That’s why Seaver provides an indicator letting you know how the cadence has evolved in the last 5 strides before jump: increasing, stable or decreasing. It is not always a bad thing to have an unstable cadence, if it is what you want; but you should always be aware of it. In a hunter class you should always aim for a very stable cadence. A decreasing cadence can indicate your horse (or the rider) is getting a bit sleepy before the fence, or on the contrary is worried and prepares to stop. An increasing one will occur with horses that rush towards the fence, it is often damaging for their horizontal balance.

Understanding shift in jump to improve your lateral control

  • Shift in jump

One last piece of info is displayed for every jump: the shift in jump and the side of that shift. The shift represents the change of orientation of the body of the horse between the moment when the forelimbs take off and the moment the hindlimbs land. It is measured in degrees (°). Between 0 and 1° we consider there was no shift: the horse stayed perfectly straight. Below 10° the shift is light. Above this value, the shift is considered large. You should always seek to reduce the shift as much as possible: the more a horse shifts, the more chances he gets to touch a poll while twisting. Furthermore in a grid or a combination with a precise distance it can reveal very difficult to make the right amount of strides if the horse is not straight in his jumps.

This phenomenon can be explained by a variety of causes: an asymmetry in hind limbs push due to pain, a well-established habit, an asymmetric rider in his seat, body position or demands (hands, legs)… In all cases if you let the horse shift and twist on a regular basis, he will tend to carry on with it. Once all physical discomfort have been eliminated as a possible cause, working with studs or polls resting on the fence, parallel to the horse, can help straighten the jump. Don’t forget to add physical preparation for the rider to help him stay symmetrical.

As the sensor does not know where the fence is, it cannot measure if you are jumping it perpendicularly and in the middle. You can have a perfectly straight jumping trajectory (0° shift) while jumping totally at the right of the fence, if you stay on your line. Likewise when jumping angled fence, even with 45° angles, you should not shift during jump: the horse must remain perfectly straight from take-off to landing.

Like a lot of Seaver data, the single value (over one jump) is interesting but the average value over the whole session is even more relevant. If a horse shifts only one time to the right, even a very large shift, you can think it was an accident (he spooked at something, or made a mistake with his legs). But if a horse always shifts to the same side, there might be a physical or technical problem with the pair, one that you will need to find and try to correct.

Let’s analyse this very good jumping session. On 16 jumps performed, 9 had a shift under 1° (no shift in green), and 7 had a light shift between 1 and 10° (orange). There were no jump with a large shift (red). On the 7 slightly-shifted jumps, about half of them were shifted to the right, and the other half to the left, with an average below 5° both times. We can consider that the horse did not show systematic shift in that training. Of course it would be ideal to have 16 jumps with 0° shift, but with values like these ones the rider probably didn’t feel the shifting. It didn’t affect the trajectories between fences, so it’s no big deal.

Be careful: the average values of shift to the right and to the left are only calculated on jumps with shift. Straight jumps where shift is between 0 and 1° are not taken into account.

We can consider that the horse (or the pair he forms with the rider) has a recurrent shifting problem if in 3 successive jumping schoolings there are more than 5 largely-shifted jumps, or if the average shift to the right or the left is over 10°. In these cases the rider is likely to lose lateral control of his horse during jumps. We would advise a lot of flat work practice, over ground poles and small crosses, while focusing on cantering straight (with landmarks for the rider’s gaze). There may also be a problem if the horse always shifts to the same side, even if it is a light shift. You might want to focus on the rider’s aids (seat, hands, legs) and make sure they didn’t provoke that shift. A physical issue can also cause that phenomenon.

Mastering all these indicators allows you to better analyze your session, jump by jump and on average. You can take into account the efforts provided by the horse, and the errors and technical achievements made. That way you can adapt the training program to progress while preserving your horse’s health capital. In addition to these punctual absolute values you may want to study the evolution between sessions or compare several horses and riders on a same exercise to assess their relative skills.

See you soon for a new article,

The Seaver team 🙂