It was a lot of clothing to wear when racing to the net to make an overhead shot. Lacoste was seeking a shirt that was more accommodating to movement. In a 1979 article from People magazine ...

Wear it in black with black trousers ... Look at any outfit where you are wearing a T-shirt. Swap that t-shirt out for a Lacoste polo, and 90 percent of the time you're going to look better.