Adults should get 150 minutes of moderate-intensity exercise per week.
This can be 30 to 60 minutes three times a week at moderate intensity or 20 to 60 minutes three times a week at vigorous-intensity.
Strength Training/Weight Lifting
Adults should train each major muscle group two or three days each week using a variety of exercises and equipment.
Very light or light intensity is best for older persons or previously sedentary adults starting exercise.
Two to four sets of each exercise will help adults improve strength and power.
For each exercise, eight to twelve repetitions improve strength and power, ten to fifteen repetitions improve strength in middle-age and older persons starting exercise, and fifteen to twenty repetitions improve muscular endurance.
Flexibility Training
Adults should do flexibility exercises at least two or three days each week to improve range of motion.
Each stretch should be held for ten to thirty seconds to the point of tightness or slight discomfort.
Repeat each stretch two to four times, accumulating 60 seconds per stretch.
Static, dynamic, ballistic and PNF stretches are all effective. (PNF Stretches are Proprioceptive Neuromuscular Facilitation stretches. This is “a method of stretching muscles to maximize their flexibility that is often performed with a partner or trainer and that involves a series of contractions and relaxations with enforced stretching during the relaxation phase. Definition source: Merriam-Webster)
Flexibility exercise is most effective when the muscle is warm. Try light aerobic activity or a hot bath to warm the muscles before stretching.