The split reins separate to connect to both sidecue and curb. The separated ends can be adjusted to give quicker reaction on either side cue or curb. As the curb strap isn't fixed, adjustment is variable, and to use effectively would need careful observation and figuring out what rein position affects which. E.G. if you raise your hands that will have a different impact than bringing your hand out. Here are Maddy's views, based on different positions, and different riding activities:
Maddy Gralak and Jack's assessment on the usefulness or otherwise of the split reins instead of double reins.
In Maddy’s words :
Fundamentally the Transcend bridle is designed for soft, gentle communication with your horse. This is done either through the sidecue ring or via the curb strap. The split reins remove the finesse that is available to a rider when they are using double reins as they are now using the one rein to act simultaneously on both options.
For this reason I would not suggest their use for dressage or those activities where a finer level of communication would be desired.
I did use these reins for a couple of dressage sessions and I really missed having the ability to differentiate my aids between the sidecue and the curb options on the bridle. My horse was totally fine and worked well with the split reins – but I personally felt like the split reins as a method of communication with him were not as precise as having the double reins.
However, that said, I do feel that the split reins could have their place when it comes to certain activities or environments. When horses can become excitable, strong and forward the rider may just be looking for something that says “stop” rather than going for a finer level of communication. The split reins can be set up to pre-determined strengths which could be amended for individual horses, riders and situations.
I found when my horse did become strong in exciting situations I appreciated just having the one rein rather than having to think about adjusting the two reins separately. One disadvantage is that you have to choose the setting you want on the split reins and you can’t adjust it once you are on, but if you know what strength of curb action you need beforehand then this shouldn’t be a problem.
Overall I think that the split reins certainly have their place, although I fully acknowledge that they will not be for everyone. I feel that they could be a useful tool for people who want to use a kind bridle for their horse but also want something to help them out when they are going into situations their horse may find exciting.