Memorial Day is when Americans pay tribute to members of the military who have given their lives in service to our country.

For some CrossFit enthusiasts, it’s a time to pay tribute to one Navy SEAL in particular with a workout that’s as tough as the man for whom it’s named.

His full name was Lieutenant Michael P. Murphy, known far and wide today as Murph.

As a kid, his nickname was The Protector, because he stood up to bullies in school and beyond.

After finishing college, Murph decided to enlist in the Navy SEALs.

As he prepared his body for the military, he came up with grueling workouts, some of which he did while wearing body armor.

Those workouts turned out to be pretty useful for fellow SEALs.

They could be done wherever SEALs were deployed, because they didn’t require much equipment beyond the body armor they already had.

And as Men’s Health explained, a good time with these workouts were good indicators of a SEALs physical readiness.

In 2005, Lieutenant Michael P. Murphy’s SEAL team was pinned down by militant fire in Afghanistan, unable to make a distress call because of the high cliffs in the area.

Murphy moved to an open area and made the call, even after being shot.

He put his own life at risk to try to save the others.

Lieutenant Murphy posthumously received the Medal of Honor for what the Navy called “undaunted courage, intrepid fighting spirit and inspirational devotion to his men.”

Two years later, a Crossfit gym in Albany, New York was honored Murph with what’s known in Crossfit circles as a Hero WOD, which stands for “workout of the day.”

It starts with a 1 mile run. Then, a hundred pullups, two hundred pushups, three hundred squats and another mile run to finish up.

All while wearing body armor.

Murph’s family joined with some of those who knew and served with him to make the Murph workout a Memorial Day tradition, to honor him and to raise money for scholarships in his name.

Since then, athletes, celebrities and more have taken the Murph Challenge, as it’s now called.

Nobody walks away from that last mile without acknowledging that this is one heck of a workout, named for a one of a kind person.

How Murph Became the Most Legendary Fitness Challenge Ever (Men’s Health)

Medal of Honor Recipient Michael P. Murphy (US Navy)

Photo via US Navy