Exercising muscles and tension bands will definitely help. The effect of muscle training and tension band is definitely not as good as dumbbell, so it is recommended to continue to practice with dumbbell.

In addition, I feel that there is something wrong with your practice method, especially the light weight. You know, if you want to grow muscles, you have to use a weight that your group can only do 8- 10. If you work in groups of 25 people, you will be exhausted, and finally you will increase your endurance.

You can find a muscle net with a lot of professional training knowledge online, study hard, and then make a scientific and suitable plan for yourself.