Gentle weight training done slowly and steadily twice a week for 12 weeks can make older adults' thigh muscles thicker and stronger.

In healthy older adults around 71 years old, doing resistance training for 12 weeks leads to measurable increases in thigh muscle size and leg strength, whether or not they previously did aerobic exercise.

Whether you use light or heavy weights, your muscles can grow about the same amount if you train hard enough—both methods work for building muscle size.

This claim says that light weight training doesn't really help older adults get bigger muscles, move faster, or get up and go quicker after doing it twice a week for 12 weeks.

Doing gentle strength exercises slowly and steadily twice a week for 12 weeks makes older adults' knee muscles stronger.

If older guys who are already active do full-body strength training three times a week for three months, they’ll get stronger legs and bigger leg muscles—even without adding extra protein to their diet.