Weight training is a type of strength training that uses weights for resistance. Weight training provides a stress to the muscles that causes them to adapt and get stronger, similar to the way aerobic conditioning strengthens your heart.
Weight training can be performed with free weights, such as barbells and dumbbells, or by using weight machines
You can also increase your strength through other types of resistance exercises, such as by using your body weight or resistance bands.
You don't have to be in the weight room for 90 minutes a day to see results. For most people, short weight training sessions a couple of times a week are more practical than are extended daily workouts.