Background: Raymond Emmett Berry Jr. (born February 27, 1933) is a former American football player and coach in the National Football League (NFL). He played as a split end for the Baltimore Colts from 1955 to 1967, and after several assistant coaching positions, was head coach of the New England Patriots from 1984 to 1989. With the Colts, Berry led the NFL in receptions and receiving yards three times and in receiving touchdowns twice, and he was invited to six Pro Bowls. He and the Colts won consecutive NFL championships, including the 1958 NFL Championship Game--known as "The Greatest Game Ever Played"--in which Berry caught 12 passes for 178 yards and a touchdown.
Context: Berry overcame several physical ailments during his football career, a fact he became famous for, but one that according to Berry was often exaggerated by the media. He was skinny and injury prone, such that when his college teammates saw him for the first time they sarcastically dubbed him, "Jack Armstrong, the All-American Boy". Reportedly, because one leg was shorter than the other, Berry had to wear padding inside his shoe in order to walk properly. However, according to Berry, this was not entirely true. In actuality, bruised nerves near the sacroiliac joint occasionally caused misalignment in his back, which in turn affected his legs and caused one to become slightly shorter; it was not a permanent condition. To alleviate this, he wore a back brace for 13 years in the NFL. That he required specialized shoes was a myth, which Berry says was perpetuated by an overzealous information director with the Colts when Berry tried to compensate for his condition by putting something in his shoe during training camp.  Due to his poor eyesight, Berry wore contact lenses when he played. Because the lenses would often slip when he did rapid eye movements toward the ball, he tried many different lenses, which led sportswriters to believe he must have had major eye problems. "I tried all kinds of lenses till we got what we wanted," he said. "I even had tinted lenses for sunny days, so I could watch the ball come right across the sun."  Berry was famous for his attention to detail and preparation, which he used to overcome his physical limitations. Considered slow for a wide receiver, he ran the 40-yard dash in 4.8 seconds. Rather than speed, he was renowned for his precise pass patterns and sure hands; he rarely dropped passes, and he fumbled only once in his career. He would squeeze Silly Putty constantly to strengthen his hands. He and Unitas regularly worked after practice and developed the timing and knowledge of each other's abilities that made each more effective. The reason for this, according to Berry, was that the two did not think on the same wavelength. "Every season we had to start all over on our timing, especially the long ball," said Berry. "He knew he had to release the ball when I was eighteen yards from scrimmage for me to receive it thirty-eight yards out. I knew I had to make my break in those first eighteen yards and get free within 2.8 seconds." He also relied on shifty moves, and by his count, he had 88 different moves to get open, all of which he practiced every week.  Even in his adult years, Berry was soft-spoken and reserved. He preferred not to draw attention to himself, and was described by sportswriter Jim Murray as "polite as a deacon, as quiet as a monk." Both as a player and as a coach, he was studious, serious, and orderly; "He was too straight and narrow--but a great guy, a hell of a guy," former Colts teammate Art Donovan said of Berry. "He was a little peculiar, to say the least."
Question: How did he develop those traits?. Whats the answer?
He would squeeze Silly Putty constantly to strengthen his hands.