• You're all caught up!

How to Build Muscle by Flexing

author image Jack Kaltmann
Jack Kaltmann is a Las Vegas-based writer with more than 25 years of professional experience in corporate communications. He is a published author of several books and feature articles for national publications such as "American Artist" and "Inside Kung-Fu." Kaltmann holds a Bachelor of Arts in English from Miami University and is a retired nationally certified personal trainer.
How to Build Muscle by Flexing
A woman flexing her upper body with a chest and shoulder stretch. Photo Credit acfrank/iStock/Getty Images

Flexing muscles is a form of isometric exercise where the muscle is contracted, or squeezed, for five to 30 seconds, without any adjacent joint movement. A common example of an isometric exercise is flexing the arm by squeezing the biceps muscles. It is difficult to build muscles only through flexing as the there is not enough stress applied to the muscle fibers to elicit an adaptive response. Isometric exercises, however, can be part of a comprehensive body building program to enhance muscular endurance and definition.

Upper Body

Step 1

Straighten both arms and cross the left arm over the right, at the elbow. Squeeze your chest as if trying to hold a pen between chest muscles. Hold for 10 seconds and repeat three more times, alternating which arm is on top.

Step 2

Place both hands behind your back, just above the buttocks, grasping the left hand with the right. Keeping the legs straight, bend forward at the waist while lifting the arms as far overhead as possible to stretch the shoulders and upper back. Hold this position for 10 seconds and repeat three more times.

You Might Also Like

Step 3

Place your hands on your hips and contract your abdominal muscles. Completely exhale and pull your abs in as far as possible toward your spine. Hold this position for five seconds and repeat three more times.

Step 4

Position both arms so the upper arm is parallel to the floor, elbows extended to the sides. Flex each arm, squeezing the biceps and holding for 10 seconds. Repeat three more times.

Step 5

Place both arms at your side. Activate the triceps by pretending to touch your wrist to the back of your elbow. Squeeze for 10 seconds and repeat three more times.

Lower Body

Step 1

Extend one leg in front of you, from either a standing or seated position. Contract the thigh muscles on the front of your leg by straightening your leg as much as possible. Hold the contraction for 10 seconds and repeat three more times. Complete one cycle for each leg.

Step 2

Lie on your stomach on the floor. Curl both legs backward attempting to touch your heel to your buttocks. This is similar to the biceps curl. Squeeze the hamstrings on the back of the thigh as hard as you can for 10 seconds. Repeat three more times.

Step 3

Return to the standing position and place your feet together. Rise up on your toes, as high as you can, flexing your calves for 10 seconds. Rotate the heels outward for the second 10-second repetition, and the toes outward for the third 10-second repetition.

Related Searches

LiveStrong Calorie Tracker
THE LIVESTRONG.COM MyPlate Nutrition, Workouts & Tips
  • Gain 2 pounds per week
  • Gain 1.5 pounds per week
  • Gain 1 pound per week
  • Gain 0.5 pound per week
  • Maintain my current weight
  • Lose 0.5 pound per week
  • Lose 1 pound per week
  • Lose 1.5 pounds per week
  • Lose 2 pounds per week
  • Female
  • Male
ft. in.


  • "Chi Mind Control"; Mike Dayton; 1978
  • "Science and Practice of Strength Training"; Vladimir M. Zatsiorsky, William J. Kraemer ; 2006
Demand Media