Karl Knopf, EdD

Karl Knopf, EdD, is director of fitness therapy and senior fitness for the International Sports Sciences Association and retired director of adaptive fitness at Foothill College in Los Altos Hills, California. He is author of many fitness books including Stretching for 50+ and a board member of Sit and Be Fit, a nonprofit organization dedicated to healthy aging.

Exercise & Fitness

Improve Your Functional Fitness

Have you stopped riding a bike, bowling or playing golf or tennis because these activities are too hard to perform?…


How to Stretch and Roll Away Your Aches and Pains

Stretching your muscles is as vital as aerobic exercise and weight training. Here, easy stretches for your neck, back, shoulders, hips, feet, more.

Exercise & Fitness

6 Common Stretching Mistakes That Can Hurt You

Are you stretching all wrong? There’s a good chance! Our expert reveals six common stretching mistakes—and what to do instead.

Exercise & Fitness

5 Do-Anywhere Stretches for Your Entire Body

These five easy-to-do-anywhere, good-for-you stretches cover your upper and lower body.

Strength Training

A Fun and Easy Way to Get Much Stronger

If you’ve ever been in physical therapy, you’ve likely used a stretchy latex tube or flat strip called a resistance…

Back or Neck Pain

3 Anti-Sitting Stretches for Your Lower Back

We all know by now how bad sitting is for our health. And we know what it feels like to…