Full grain leather is cow hide taken from below the hair of the cow: the reason being that the hide at this location is the most compact and has the strongest fiber strength.
Full grain leather has the least amount of imperfections, so it rarely needs to be sanded, snuffed or buffed; techniques that are used on lower quality parts of the cow hide to remove imperfections. Therefore, the benefit of using full grain leather is two-fold: 1) it looks better 2) it's stronger and more durable. Due to the extra expense of using full grain leather, most sportswear manufacturer's tend to use top-grain leather or even synthetic versions of leather. Adidas are one of the exceptions, they use full grain leather in a range of their products; typically heritage products and footwear. The Adidas Superstar sneaker (shown above) has a full grain leather upper: the shoe was released in 1969, and was originally released as a basketball sneaker; hence the rubber shell toe.