Strange but true: watermelon juice, of all things, offers fast and effective relief from post-exercise muscle soreness. The secret ingredient, Science Daily reports, is L-citrulline, an amino acid found naturally in the big green orbs. Science Daily cites a recent study, published in the Journal of Agricultural and Food Chemistry, for which researchers added even more L-citrulline to watermelon juice, and tested the soreness relieving ability of natural juice, enhanced juice, and a control beverage, all taken one hour before exercise. The results please…both the natural juice and the enriched juice relieved muscle soreness in the volunteers. L-citrulline in the natural juice (unpasteurized), however, seemed to be more bioavailable — in a form the body could better use. The bottom line: do it naturally.