Credit: Splash News

Pippa Middleton is pounding the pavement yet again.

On Saturday, the 27-year-old Brit took part in the Highland Cross 2011, a 50 mile duathlon which takes place in the Scottish Highlands.

Arriving by helicopter, Duchess Catherine's little sister completed the 20-mile run and 30-mile bike ride as part of the Affric Brats team. Dressed in all black, the athletic beauty was all smiles by the time she approached the finish line. See more pics of Pippa at the duathlon.

Earlier this month, Middleton participated in the GE Blenheim Triathlon at Blenheim Palace in Woodstock, England. (At one point, she collided with a topless mystery man!)

As a student at Marlborough and Edinburgh University, Middleton played hockey and tennis and, like her royal sister, continues to work out daily.

The recently single star -- several sources confirm in the new issue of Us Weekly that Middleton recently split with beau of one year Alex Loudon -- is also a Pilates devotee and enjoys skiing, swimming and jogging.