Former San Antonio Spurs forward Tim Duncan retired from the NBA following the 2015-16 season, but it appears the 41-year-old is doing well to remain in fighting shape.

This past Wednesday, the Facebook page for Echols Fitness posted a 23-second video of the five-time NBA champion sparring.

While Duncan admittedly isn't the fastest fighter in this short clip, his size, athleticism and skill level would make him an intimidating opponent for any novice.

Not surprisingly, Duncan's fundamentals look strong.

[Facebook]