Ease into your springtime riding.
If your horse has been laid off over winter, be sure to condition him in the spring before riding in earnest. Conditioning increases the amount of blood his heart can pump to deliver oxygen to his muscles. Waste products clear more readily from his system, so he not only has more energy, but also fatigues more slowly. Springtime conditioning also helps protect tendons, ligaments, and joints from injury. Start with 20 to 30 minutes of walking and trotting at least every other day for 6 to 8 weeks, then gradually increase both the length and the intensity of work.