Found some of the ones I did! Be warned: These sound really easy, but if you have a week quad, it can be a nightmare. I did these about...once a day for a few weeks. I noticed a difference in probably 2 weeks because my right pant leg was tighter around my thigh.
I found them from this website: Knee Pain Exercises Quad Strengthening Contractions:
Sit in chair. Move forward so that you are sitting at edge of chair. Extend legs, heels to floor. Keep knees straight (or as straight as possible if you have arthritis.) Tighten thigh muscles. Hold for count of 10. Relax for count of 3. Do 10 repetitions. You can do this several times throughout the day. You can build up to 2 or 3 sets of 10 repetitions at a time. Quad Strengthening Leg lifts:
Lie flat on back. Bend left knee at 90-degree angle, keeping foot flat on floor. Keeping the right leg straight, slowly lift it until right foot is the height of the left knee. Hold for a count of 3. Repeat 10 times. Switch sides. Work up to 10 sets of 10 over several weeks. Safety Tip:
Leg lifts: Lifting both legs at the same time causes excessive stress on your lower back so
only lift one leg at a time; the opposite leg should be kept slightly bent with foot on floor. Quad Strengthening Short-Arc Leg Extensions:
Sit or lie on floor. Place a rolled up towel under your thigh for support. Keep you leg straight and raise your foot about six inches off the floor. Hold for 5 seconds. Slowly lower your foot, bending your knee. Do 10 repetitions. Switch sides. (NOTE: When I did these, my physical therapist said it's easier to take a coffee can and wrap a towel around it ((mostly for comfort)) and do this.)
One that's not on the site that I did and is ridiculously difficult (but rewarding!) for as easy as it sounds.
Sit with your back flat against a wall and your legs straight out in front of you. I had my hands flat on the ground at my sides. Take the foot you plan on lifting and turn it out at a 45 degree angle and flex it up. Then lift your entire leg about 2-3 inches off the ground and set it back down. I think I did...I want to say 3 sets of 15 of these. Maybe less.