The concept that you must know is called “Progressive Overload” !
What is exactly progressive overload?
This concept means that an individual needs to continually increase the demands on the musculoskeletal system , in order to gain progressively in muscle size, strength and endurance. In other words, in order to get stronger you shall progressively lift more weights.
The progressive overload principal doesn’t just apply to resistance training and increasing muscle growth and strength, it can also be applied to increasing bone and connective tissue strength (through resistance training) as well as cardiovascular fitness.
Ways To Create progressive overload
1 – Increase Resistance
Progressively increase the weight you lift as you become stronger and the weight becomes easier.
2 – Increase Sets
Increase the number of sets you perform for a given exercise. Instead of 2 or 3 sets maybe you’ll want to increase to 3 or 4 in order to really fatigue the muscle(s).
3 – Increase Repetitions
Increase the number of repetitions you perform for a given exercise.
4 – Increase Frequency
Increase how often you train a certain muscle or muscle group. This technique is most useful for improving lagging or weak muscles or muscle groups. The traditional approach to training a muscle or muscle group only once a week may not be sufficient enough for every individual to make continual gains.
Learn to listen to your body and make sure that muscles have had enough time to recuperate between training sessions before increasing frequency. Every once in a while though it could be useful to train muscles even if they haven’t fully recovered in order to shock them and keep them guessing.
5 – Increase Exercises
Increase the number of exercises you perform for a certain muscle or muscle group with the addition of a new one to your current program.
Decreasing the rest time between consecutive sets will force your body to adapt metabolically by removing toxins and other byproducts of anaerobic exercise (weight lifting) faster and more efficiently over time. Eventually you will be able to lift more in less time.