Question: exercises that are easy on the knees?
Answer: Inner Thigh Leg Lifts. Inner thigh leg lifts are great for toning and strengthening the inner part of of your thigh. ... 
Outer Thigh Leg Lifts. Outer thigh leg lifts are very similar to inner thigh leg lifts. ... 
Partial Squats. ... 
Low Impact Cardio. ... 
Pushups. ... 
Seated Tuck Jumps. ... 
Calf Raises. ... 
Foam Rolling.