Warmup. A very important practice for both horse and rider. Imagine if a marathon runner, just got up every morning and ran 8 miles, without doing anything before hand. Horses are athletes just like the runner and they need time to stretch and warm up their muscles and body before work just as well. No matter what type of work you do, you should warm your horse up at the beginning and cool him down at the end.
(My own Summary of USPC Manual)
A good warmup:
-Is essential for EVERY ride.
-Is used to prevent injuries, strain, and tears. It supples, stretches and warms up the muscles.
-It helps to develop rhythm, balance, and relaxation for both horse AND rider.
-It prepares both horse AND rider physically and mentally.
I hope everyone takes this into consideration, because with a warmup, your horse will not only perform smoother, but you will also be preventing injuries as well.