The Q system offers an optional ridden evaluation module that includes a sensor worn by the rider. The rider sensor allows for detection of sit versus posting trot and provides two separate analyses in the same report. However, the Q can be used in ridden evaluations without the rider module with some considerations.
The activity of the rider can affect the measured asymmetry of the horse. Studies have shown that when the rider is posting (i.e. rising in the saddle when the outside forelimb is forward), the vertical movement of the rider commonly creates an artefactual effect on measurement of hind limb lameness. Posting causes apparent opposite hind limb lack of push off, with decreased pelvic rise. This occurs because the rider’s momentum is downward, opposite in direction to the upward momentum of the pelvis, when the opposite hind limb is at the end of stance or pushing off. The opposing momentums cause the whole pelvis to rise less after push off. Riding to the left posting on the right forelimb causes an apparent left hind limb lack of push off. Riding to the right posting on the left forelimb causes an apparent right hind limb lack of push off. It is uncommon for the sitting trot to create an artefactual lameness (compared to straight line in hand evaluation).
Therefore, the clinician can anticipate the following effects from the rider posting:
- Horses with no hind limb abnormality may measure with hind limb push off lameness opposite the side of posting.
- Horses with existing lack of push off lameness in the opposite side hind limb may measure with worse lameness.
- Horses with existing lack of push off lameness in the same side hind limb may measure as less lame, a masking of hind limb lameness.
Data Collection Guidelines
With Rider Module:
- The rider module allows for collection of sit and post trot in the same trial. You can choose to collect only one activity, e.g. sit trot or post trot. However, it is always best to at least collect sit trot as this will induce the least rider artifact (and it is useful to compare against posting trot for artifact, if posting trot is desired).
- By using the rider module, you will see “ride left” and “ride right” trial type options in the trial set up. You can collect either direction first, but both directions should be performed (as separate trials).
- If the rider is traveling the entire arena, an easy protocol is to collect one activity (sit or post) one full time around the arena, then direct the rider to switch to the other activity (sit or post) and collect another full time around the arena. No pausing of the data collection is necessary.
- Be sure that the rider is posting on the correct diagonal (outside forelimb). If at any point you notice the rider is not on the correct diagonal, have them switch and collect additional data (data collected posting on the wrong diagonal will automatically be discarded and not be included in the rider module analysis).
- Perform the data analysis and set up for the same trial collection in the opposite direction.
- Use the rider comparison report to create a ride left and right report comparison.
- If smaller circles are used, collect approximately two full screens worth of live data for each activity (similar to the lunge protocol) which should provide approximately 50 strides of each activity.
Without Rider Module:
- Lunge left and lunge right trial types can be used in lieu of the rider module; however, sit and post trot activities cannot be conducted within the same trial. A note can be made in trial set up that the evaluation is ridden and whether the rider is sitting or posting. These notes will appear on the bottom of the report.
- Collect a sitting trot trial consisting of one full time around the arena (or if smaller circles, collect approximately 2 screens worth of live data). Analyze the data and repeat the trial in the opposite direction. If posting is desired, conduct the same protocol at the posting trot.
- Use the lunge left and right comparison report to compare directions. This will also allow the use of the lunging AIDE, which accounts for expected asymmetries on a circle. This is helpful when riding in a small circle at the sitting trot. However, the AIDE comments pertaining to expected head and pelvic movement asymmetries that may be normal in lunging horses may not be applicable if the rider is using the entire arena and the horse is not on a constant small circle.
- Be sure you are comparing left and right sitting trot or left and right posting trot. To compare a ride left sit trot to a ride left posting trot, or vice versa, use the “General Comparison” report option.
Evaluating Ridden Data
- If the data was collected at the posting trot, interpret any opposite hind limb lack of push off with caution.
- Comparison to sitting trot under the same circumstances should be performed in order to identify posting artifacts.
- When using the rider module, any lack of push off on the inside hind limb when posting will be identified as potentially rider induced in the AIDE statement.
- If tracking on a small circle, consider the influence of torso tilt and surface characteristics. Remember that the posting effect on the inside hind limb is opposite to the expected outside hind limb lack of push off in horses lunging on soft ground. These effects may cancel each other out.
- If traveling in a large arena, where there are many more strides along the straight lines than in turns, the effects of torso tilt are minimized.
*For complete instructions on using the Q Rider Module, see the User Manual Addendum, visit equinosis.com/rider-manual
Effects of Posting on Pelvic Movement
Comparison of sitting trot to posting trot. Note the increased push off asymmetry evident on the inside hind limb (when posting on the outside forelimb).
Comparison of sit and post trot riding to the right. Notice the LH lack of push off measured at the sit trot (left image) switches to the RH when posting (right image).