Last night’s SAM Party in the Park was joyful and dusty. My only beef is with the On the Double double-dutch team. Before they took to the stage, the lady jump-ropers were full of sass and promise. Their cheerleader-esque outfits were nicely coordinated, but once they started turning the ropes, nothing else about them was: The girls failed to execute just about every trick they attempted. The short routine was repeatedly punctuated by the anticlimactic thwack of the plastic-beaded rope catching on a leg or the ground, halting the action. I’d seen On the Double before and had chalked that lackluster performance up to them having an off night or a few too many beers. But no, yesterday validated my suspicion: They’re just not good at double-dutch.