Not really, because at one stage your body will get adapted to 7kg dumbbells and in order for the muscle to keep growing, you have to increase the weighs.

The answer is 15.43 lbs (approx.). Kilogram is the SI unit of mass and pound is an imperial unit of mass. To convert from kg to pound, multiply the kg unit by 2.20462.

The density of pure water at room temperature is generally accepted as 1g/cm3, and 1 cm3 is equal to 1 mL. 7L = 7,000mL x 1g/mL = 7,000 g = 7kg To find the weight in pounds, 7kg x 2.21 = 15.47lb