L-citrulline is an amino acid with antioxidant and blood vessel-dilating properties. Some studies have shown that supplementing with it can enhance athletic performance, relieve muscle soreness, and speed post-exercise recovery time.
Watermelon is a rich source of L-citrulline, but it's not known if eating the fruit (or drinking the juice) has the same effects on the body as supplementing with L-citrulline.
Fresh is best
The new study compared the effects of plain watermelon juice with an L-citrulline-enriched watermelon juice at reducing post-exercise muscle soreness and investigated the effects of heat pasteurization on L-citrulline absorption from watermelon juice.
Seven college-aged male athletes took part in the study. One hour before an exercise session, they were given 500 ml of unpasteurized watermelon juice, unpasteurized watermelon juice containing an extra 1.17 gram of L-citrulline, or placebo. Next, they engaged in intense physical activity consisting of cycling on a stationary bike for eight, 30-second sessions, with a short break in between the rounds. Each participant sampled every drink, with five days between the test sessions.
The men reported on their level of perceived exertion throughout the exercise sessions and muscle soreness after 24 and 48 hours.
Both watermelon juices (plain unpasteurized and unpasteurized with added L-citrulline) helped lower heart rate during the recovery period and significantly reduced muscle soreness in the athletes after 24 hours. There were no differences in perceived exertion between the groups.
Test tube studies were also carried out to simulate the absorption of the unpasteurized and pasteurized watermelon juices and plain L-citrulline.
L-citrulline absorption was highest in the unpasteurized watermelon juice. "This indicates that (unpasteurized) watermelon juice is a more suitable vehicle for the transport and bioavailability of L-citrulline than a pure standard, that is, a pharmacological formulation," commented the researchers. "This amino acid could be supplied as watermelon juice or as products enriched in L-citrulline from watermelon extraction."
Beat post exercise pain
Besides drinking watermelon juice, try these tips to decrease muscle soreness after your workouts.
- Get rest. Post-exercise muscle soreness is due in part to tiny tears in the muscle. These tears are a necessary part of building bigger, stronger muscle, but they also need time to repair. Make sure to take rest days, especially between your more intense workouts. These "off" days allow the soreness to dissipate and help you to get the maximum results from your workouts.
- Soak it out. Try an Epsom salt bath after a bout of intense exercise to ease weary muscles. For best results, use one quart-to-one half gallon of Epsom salts per tub full of water.
- Time your protein. Make sure you eat something with protein in it--a hard-boiled egg, a slice of turkey, a glass of milk, a handful of nuts, or a smoothie with protein powder--as soon as possible after exercising. Timing your protein not only aids in building stronger muscles but it also helps inhibit post-exercise muscle protein breakdown.
(J Agric Food Chem 2013;61:7522?8)