At 81, Jean Stewart was frustrated by her growing frailty, so she decided to get active. Now 96, push-ups, kettlebell squats and pushing a weight-loaded sledge keep her strong ...

Jim Dreeben, 83, took up CrossFit in his 80s and got hooked. He does 100 push-ups and also planks six days a week, and his doctor told him to keep going. Dreeben's active lifestyle includes kayaking, ...