The head slap was a devastating weapon for a defensive lineman, the football equivalent of a Joe Frazier left hook.
At the snap of the ball the lineman would come out of his stance and club the blocker upside the head with his forearm. Done with sufficient force, it could knock an opponent off-balance or even off his feet.
The NFL eventually outlawed the head slap because it was deemed too dangerous, but in the 1960s and '70s it was the go-to move for pass rushers and none used it better than Claude Humphrey.
When the 6-foot-5, 260-pound Humphrey slammed his hand against the helmet of an offensive lineman, it sounded like a sledgehammer hitting a rock. There were times when Humphrey landed a blow and the opponent's knees would buckle. The poor guy's ears would be ringing the rest of the day.
"Deacon Jones (Rams Hall of Famer) may have invented the head slap, but Claude Humphrey got it outlawed," said former Eagles coach Dick Vermeil. "Claude's head slap was devastating."
Humphrey, who finished his career with the Eagles in 1981, will be inducted into the Pro Football Hall of Fame today. Humphrey played 14 seasons in the NFL and had his best years in Atlanta (1968-78), but he was a valuable contributor to the Eagles' first Super Bowl team.
"You improve your football program by adding quality football players," Vermeil said when he acquired Humphrey in 1979. "Claude Humphrey is a quality football player. I consider him the best pass rusher in professional football. Absolutely the best. No question."
Humphrey was retired when the Eagles traded for his rights. He walked away from the game one month into the 1978 season. He was 35 years old and frustrated after a decade of losing in Atlanta. He also was frustrated with the defense the Falcons were playing. It was a read-and-react defense, far too passive for an attacking, fire-off-the-ball pass rusher like Humphrey.
Marion Campbell, who coached Humphrey in his Pro Bowl years with the Falcons, was the defensive coordinator for the Eagles. He believed Humphrey had plenty of good football left in him; he just needed to be in the right situation. Campbell convinced Vermeil to trade for him. It didn't cost the Eagles much – just a pair of fourth-round draft picks – and it proved to be a great investment.
"I wasn't going out and kicking guys in the butt," Humphrey said, describing his dissatisfaction in Atlanta. "But coming to Philadelphia and playing for Coach Campbell again will put some adrenaline back in my blood."
The plan was to use Humphrey as a pass rush specialist, but he played so well that he wound up as a starting defensive end. In 1980, he led the team with 14.5 sacks, although the stat was not official until 1982, as the Eagles allowed the fewest points in the league.
"In all my years of football, rarely have I seen a player play that position with as much skill and determination on a consistent basis," Campbell said. "In practice, in game situations, every day of the week, every game of the season. If he's not getting to the quarterback three or four times a game, he's not enjoying himself."
"Claude was a great leader," Vermeil said. "He was a veteran player, a Pro Bowl player, yet he was one of the hardest workers on the team. He set a great tempo and had a great attitude. He could laugh and have a good time, but he was a very intense competitor."
Humphrey attended Tennessee State and was a first-round pick of the Falcons in 1968. One day coach Norm Van Brocklin was walking a visitor through the Atlanta locker room and pointed to Humphrey's stall.
"That's where our team dresses," Van Brocklin said.
Humphrey had 11 sacks in his first season and was named Defensive Rookie of the Year. He missed all of the 1975 season with a knee injury, but came back the following year to set a career high with 18 sacks. He came to Philadelphia three years later to join Vermeil's Eagles in hopes of finally making it to a Super Bowl.
A memorable moment from that season, captured by NFL Films, was Vermeil hugging Humphrey on the sidelines as the final seconds ticked away in the NFC Championship Game. The Eagles were about to celebrate a 20-7 win over Dallas and Vermeil had his arms wrapped around Humphrey's waist.
"You know where you're going?" Vermeil asked.
He turned to the other coaches and players and said: "He's going to the Super Bowl, that's where he's going." Vermeil then laughed and hugged Humphrey again.
Now Claude Humphrey is going to Canton, Ohio, to take his place among the legends of the game.
An award-winning writer and producer, Ray Didinger was inducted into the Pro Football Hall of Fame in 1995. He has also won six Emmy Awards for his work as a writer and producer at NFL Films. The five-time Pennsylvania Sportswriter of the Year is a writer and analyst for Comcast SportsNet. Didinger will provide Eagles fans a unique historical perspective on the team throughout the season for PhiladelphiaEagles.com. You can read all of his Eagles History columns here.