Effect of watermelon (Citrullus vulgaris) rind juice in muscle endurance in healthy non-athlete volunteers

Excessive workload, lack of regular physical activity and unhealthy diet are commonly experienced by most of the people in modern society. These conditions lead to fatigue and decreased productivity. Previous studies showed that consumption of watermelon juice showed ergogenic effect due to the high content of amino acid citrulline. Despite rich of citrulline and another nutrients, watermelon rind is usually discarded and considered unedible. Therefore we are interested in studying the ergogenic effect of watermelon rind juice (WRJ) in particular to increase muscular endurance in healthy non-athlete volunteers. Methods. Twelve healthy male subjects with aged between 18-20 years old were volunteered to involve in this quasi-experimental study with cross-over design. Body weight and height were measured to obtain Body Mass Index (BMI) value. Blood pressure (BP), heart rate (HR), respiratory rate, blood lactate and muscle endurance in push up test were measured after consumption of mineral water. Three days later, the same parameters were measured from the same subjects 60 minutes after consumption of 500 ml WRJ. Result. We observed no significant difference in BMI among subjects. Despite not statistically significant, the mean of BP after push up challenge was slightly lower following WRJ consumption than mineral water (117/80 mmHg vs. 115/75 mmHg, respectively). The decrease of blood pressure was coincided with the increase of mean HR indicating vasodilatation effect of WRJ. As expected, we found the increase of muscle endurance in 45% subjects following WRJ consumption. However, blood lactate level was increased. Conclution. We concluded that WMJ supported muscle endurance in push up test with slight vasodilation effect in healthy, young non athlete-volunteers.