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While professionals may make it seem effortless, a good canter results as much from the rider's efforts as it does from the horse's. As you canter, your body should be positioned to open the front (leading) shoulder of the horse and to cue the horse behind the girth, all while adding forward movement. Assume the following posture while you trot to prepare to transition into a canter.  Keep your back straight. Keep your chest up. "Open" your chest by drawing your shoulders back gently. Use the core muscles of your hips and abs for balance. Ideally, you should be able to canter without pulling on the reins, pommel, or saddle horn to steady yourself. As you work into the canter, maintain good rein contact contact, but open the inside rein of your horse while holding a firm grip on the outside rein. This will give your horse important support on the diagonal beats. Note, however, that the goal here isn't to support the horse too heavily, as it needs to develop its own sense of balance while cantering. As described in the section above, cuing a horse to canter involves several simultaneous motions of the rider's body. Follow the steps below to start cantering:  Turn your torso and shoulders (keeping your hips straight ahead) so that your shoulder on the outside is positioned slightly further back than your shoulder on the inside. Move your outside leg back. As you do this, give pressure with your inside leg and slide your inside hip forward slightly. Use the inside rein to pick up the correct lead. This also opens up your horse’s leading shoulder, helping them to understand your intentions while keeping their movement "collected."  Using your rear leg, squeeze your horse’s barrel and ask for increased speed. Note that some horses are also trained to shift into a canter when you cue them with a "kissy" noise (different than clucking for increased speed), so you may need to do this at the same time. Make sure you are cuing your horse behind the girth — that is, with your feet a few inches back from where they would ordinarily hang. In addition, try not to move your hands forward. These mistakes can get you a fast trot or a side-pass. One of the best things about the canter is that it's actually fairly easy to ride. Unlike a trot, a canter is very smooth for the rider, giving a "More floaty" feel rather than the "bumpier" one of the trot. However, it is possible to ride the canter incorrectly, so use the steps below to ensure you're sitting correctly:  Hold the reins without pulling on them. Just like when you cued the canter, you should have increased contact on the outside rein and light contact on the inside rein. If you feel out of control and are pulling on the reins for balance, then you're going too fast and you should slow your horse down. Stay balanced in an erect, upright posture. Don’t lean forward or to the inside. Although it may feel like the other way around, the horse actually gets much of its ability to balance based on what you’re doing on its back. If you’re out of balance and tipped forward and in (as many inexperienced riders have a tendency to do), your horse will have a hard time not doing the same. Avoid gripping with your legs. As with trotting, it can seem instinctual to “hold on” to the horse using your legs. However, this will give the horse mixed signals, as it's usually a cue to speed up. Similar to tugging on the reins, if you feel like you can't stay in the saddle without gripping with your legs, slow down until you can remain seated comfortably. A half-halt is essentially a partial stop, just as its name suggests. The half halt can be performed at any speed and is done similar to the way you would cue a regular halt. This technique gets your horse’s rear feet on the ground, which gives it the necessary strength and balance to either start a collected canter or get their movements under control. You don’t have to cue a half-halt in order to canter, but doing so will give your horse better grounds for moving into the faster gait. Use the steps below to cue a half-halt:  At a canter, maintain a soft supporting leg as you sit up and brace your back in preparation for a halt. Let your elbows come back and put a little pressure on the reins as if you're asking to transition into a trot. As soon as you feel your horse respond, add more leg, soften your fingers on the rein, and resume cantering. This may feel like you're asking your horse to "canter in place" for a brief moment.

Summary:
Start with open, erect riding posture. Open your horse’s shoulder with the reins. Use body cues to ask for a canter. Sit the canter. Be ready to cue a half-halt.