This awesome smoothie is made from sour or tart cherry juice. Sour (tart) cherry juice has been shown in several studies to prevent post exercise soreness. The polyphenols (flavonoids and anthocyanins) found in tart cherry juice help lessen oxidative damage induced by the exercise and reduces inflammation in the body. Tart cherries are Montmorency cherries and are different than regular cherries. You can find sour cherry juice in health food stores and some green grocers.