Here is a superset you can add into your routine for your back and bicep day.
Single Arm Dumbbell Row 3×15 ea arm
Physio Ball Crunches 3×15
Challenge yourself with the weight you use.
For the dumbbell rows keep your back flat and belly button pressed to the spine. Elbows in close to the body. No chicken wings.
For the crunches…keep your belly button pulled in to the spine to keep the back flat and everything aligned straight. Tuck the hips under. Shoulders over your wrists. Laces on the ball.