John_V 

If you don't want to constantly stretch during your long rides, learn to use warm up and cool down periods. Start off with a little slower speed than you would normally and work your way into your normal speed. I do about 1 1/2 miles of warmup at 75-80% of my normal speed (with ample coasting) and then do a cool down period, for about the same distance before the stop, at the same rate of my warmup. I do a lot of long distance riding and have never had any restart fatigue issues using this method. I very rarely do any stretching before, during or after a ride. I'm not sure that this will work for everyone or if it will work for you. I know that it definitely works for me.