HOW SUPPLE IS YOUR HORSE?
If your horse is struggling with serpentines, resist the temptation to just keeping riding them. Instead, try some different suppling exercises first. These can help by making it easier for your horse to deal with the smooth changes of bend needed for a good serpentine.
Alex suggests:
1 Work on three tracks (shoulder-in) or on four tracks (leg-yield and travers). This will help improve suppleness through the back and encourage the hindleg to step under further.
2 Increase and decrease the size of a circle (on both reins). Use your outside leg and rein to decrease the size of the circle and use your inside leg to outside rein to push your horse’s frame out evenly when increasing the circle.
3 Work through the gears in trot — in other words, change from working trot to medium trot and back again. This helps the throughness of the trot and encourages the muscles through the back to stay relaxed.
4 Practise more acute transitions such as trot to halt, halt to trot, walk to canter and canter to walk to keep your horse on the aids and to check you have the ability to rebalance and increase the impulsion quickly if needed. Remember to ride all transitions smoothly and in a forward, positive way — acute ones like these need practice and require you and your horse to be completely focused on each other.