Denise Austin, 67, shared a “low-impact,” “#FitOver50” workout video. In the video, Austin demonstrates a jumping jack alternative. The “half jack” is an effective move that is “easy on your body,” ...

Jumping jacks look simple, but they reveal a lot about how strong your heart and lungs still are. The move challenges endurance, rhythm, and coordination. All vital markers of youthful vitality. After ...