Do your legs need work?
Moving forward and springing off your foot will give your punches much more power. This is especially true of uppercuts, which depend on the strength of your calves, glutes, quads and hamstrings for explosive power. Boxers must bend at the knees for various movements such as bobbing, weaving or moving explosively to hit or not be hit. Boxers employ these movements to find placement for their punches. Side stepping, pivoting, and bobbing movements will enhance your lower body strength, agility and endurance.
Any boxer, or kick boxer knows that good legs are necessary for success.