Practicing fire-type superpowers consumes energy and also enhances strength. At the same time, the continuing practice fortifies the fire powers. As Li Ming exercises intermittently, his fire powers have already increased by at least forty percent compared to when he began.
Water-type superpowers likewise deplete energy when practiced, but the result is increased stamina. His water powers will grow stronger with practice, however, the increased water and fire power do not have any direct relation to physical strength.
One could liken it to something dependent on the physique. Although it helps promote physical growth, it eventually grows independently.
Once he has depleted his strength through practice and wakes up from a good night's sleep, not only will Li Ming's strength increase, but the strength of his water powers will also grow.
Also improving—his energy!
"This is truly miraculous," he thought.