Mr Muscleman ranks as the all-time leading money-winner bred by Brittany Farms or Brittany Farms and partners. At the time of his retirement, he was one of only two horses in harness racing history to win $1-million or more in two separate racing seasons, which is a testament to his durability and his will to win.

The modest yearling purchase, from the first crop by Muscles Yankee, was a stakes winner at both 2 and 3. He went on to achieve his fame as an older horse, three times capturing Dan Patch divisional honors for his age and gait and twice leading the annual money-earnings category for the same.

The multiple classics winner in the U.S. and Canada represented the United States in the prestigious Elitlopp Trot in Stockholm, Sweden in 2007. He finished second and third against an international field after he swooped the field in his elim to set up the eventual winner.

His Hall of Fame driver Ron Pierce said of him: "He was the best horse I've ever driven. The toughest, the classiest, the gutsiest. He covered the ground so easily...he needed three strides to get where all the other horses needed four."

In the fall of 2009, Mr Muscleman became the first trotter to retire to the "Hall of Champions" at the Kentucky Horse Park. He was elected to the Harness Racing Hall Of Fame in 2016.