This condition, loss of muscle tissue, becomes worse as we age. A study pointed out that for example, a 20-year-old male has about 800,000 fibers in his Vastus Medialis (front portion of the quadricep) But a 60-year-old on average, has just 250,000 fibers. Sarcopenia causes some disability or certainly, less capacity.
So, especially as you reach 60 or beyond, you need to lift weights twice a week so that Sarcopenia will be much less a factor in movement capacity, falls and injuries.
Use it before you lose it.