What are good, easy workouts for older individuals, pregnant women, or injured athletes?

Walking, bike, swim: In general, I’d recommend an aerobic activity such as walking, cycling, or swimming. You can self adjust the intensity and stop when fatigued. You also should do some light weights for arms and legs which help regarding osteoporosis. Also, some gentle stretching is helpful especially after doing some aerobic exercises to prevent the muscles from tightening up.