What an isometric bicep curl is
In an isometric exercise, the muscle contracts while the joint stays still. An isometric bicep curl means holding your elbow at a fixed angle while the biceps work against a resistance that does not move. You do not need a dumbbell: a towel, a doorframe, your other arm or a sturdy strap can supply the resistance.
Do isometric bicep curls work?
They can build strength at the joint angle you train, and they are easy on the joints and simple to do anywhere. Research on isometric training suggests it can contribute to strength and muscle size when effort is high, but results vary, and dynamic training through a full range is usually considered the main driver. Isometrics are a useful addition, especially at home, rather than a full replacement for weights. The key variable is effort: a gentle hold will do little.
How to do an isometric curl with a towel
- Stand and place the middle of a towel under one foot, or hold both ends in one hand with the loop under your foot.
- Hold the free end with your palm facing up and your elbow at your side.
- Bend your elbow to about 90 degrees.
- Pull up as if curling, but keep the towel tight enough that it does not move. Pull firmly and steadily.
- Hold for 10-30 seconds, then relax.
Keep your shoulder down and avoid leaning back.
Self-resisted isometric curl
Make a fist with one hand and place the other hand on top of the wrist. Curl the bottom arm up while pressing down with the top hand, so neither arm moves. Switch roles after a set. Use a smooth, strong push rather than a jerk.
Doorframe and table variations
- Doorframe curl: stand facing the frame, grip the edge with your palm up and elbow bent, and pull toward you without moving.
- Under-table pull: sit under a sturdy table with your palms up against its underside and pull up, holding the position. Check that the table is stable first.
- Strap anchors: a closed strap in a door can serve the same purpose. Make sure the anchor is secure.
Sets, holds and frequency
A general starting point is 3-4 holds of 10-20 seconds per arm at a firm, but not maximum, effort, resting 30-60 seconds between holds. Try 2-3 sessions per week. Vary the elbow angle (for example 45, 90 and 120 degrees), because strength gains tend to be specific to the angle trained.
Progressing without equipment
- Increase hold time gradually.
- Pull harder across sessions.
- Use several elbow angles.
- Add slow lowering reps, such as a bodyweight inverted row (see the no-equipment lats workout) or a chin-up negative if you have a bar. For more pulling options, see our guide to compound exercises for back and shoulders.
If you later want to add speed and power, see explosive bicep exercises.
Mistakes and limits
- Holding your breath: breathe steadily.
- Shrugging or leaning: keep your torso still so the biceps do the work.
- Expecting dumbbell-style results quickly: bodyweight options have a lower load ceiling.
- Pain: stop if you feel sharp elbow or shoulder pain. People with high blood pressure or a heart condition should be careful with hard isometric holds and may wish to ask a doctor.
FAQ
How do I perform an isometric bicep curl? Bend your elbow to a set angle, pull against something that will not move, and hold.
How can I do bicep curls with no equipment? Use a towel, a doorframe, your other hand, a backpack or a water jug.
How often should I train them? Two to three times a week works for most beginners.