Short-arc--or terminal knee extension--exercises strengthen the muscles in your quads.

Here's how to do them.

There are two ways to set up this exercise.

You can tie the ends of an exercise band together to form a loop.

Then put the knot in the jam of a door and close the door to hold it in place.

Or, you can tie the band around the leg of a heavy table.

In either case, the band needs to be at the same height as your knee.

To exercise your right leg, loop the other end of the exercise band around the back of your right knee and step back until the band starts to feel tight.

Keep your right leg--the leg with the band around it--somewhat bent.

Put your left leg about a step behind the right one.

Then slowly straighten your right leg by tightening the thigh muscles of your leg.

The band should be tight enough that your quad muscles have to work to straighten the leg.

If you need more tension, you can step back a little farther.

Hold this straightened position for about 6 seconds.

Then return to the start position--with your right knee somewhat bent.

Do this exercise 8 to 12 times, resting between each time, if you need to.

And then switch sides and do the other leg.

Some soreness or discomfort may be expected, but stop doing an exercise if you have increased pain.