Biceps exercises tone and define the muscles of your upper arm. They come in a variety of styles, two of which are the hammer curl and the preacher curl. You perform both by raising your hand toward your shoulder, but each recruits different muscles. Understand the difference to select the exercise that best fits your arm workout goals.
When You Use Dumbbells
When you perform a hammer curl, you either sit or stand using dumbbells as the resistance tool. Stand or sit tall and hold a dumbbell in each hand. Straighten your arms at your sides and face your palms toward your body. Exhale and bend your elbows to raise the dumbbell toward your shoulders. Inhale and straighten your arms to start position. As you perform the hammer curl, keep your spine and wrists straight, your stomach tight and use a light grip on the dumbbells. Raise both hands at once or alternate the hammer curls for variety.
When You Use the EZ-Curl Bar
You typically perform a preacher curl from a seated position, but standing preacher curl benches are available. This exercise uses an EZ-curl bar with free weights secured to the ends as the resistance tool. The bar is placed in the holds on the front of the curl bench. Sit on the bench and position the height of the seat rest so your elbows meet the middle of the curl pad. Stand and grasp the bar with your palms facing up. Hold onto the bar at a position that is near or slightly more narrow than shoulder distance apart. Bend your elbows to raise the bar toward your shoulders and return to a seated position. Inhale and slowly straighten your arms as you lower the bar. Keep a slight bend in your elbows. Exhale and bend your elbows as you raise the bar toward your shoulders.
The different hand positions between the hammer curl and preacher curl exercises are what change the muscle focus. The palms-up position in the preacher curl causes your biceps brachii and brachialis muscles to contract. The biceps is the largest muscle in the front of your upper arm. The palms-in position during the hammer curl uses the brachioradialis muscle. This muscle begins on the lower portion of your upper arm, crosses over your elbow and attaches near your wrist.
The Difference in Arm Engagement
Bicep exercises are categorized into unilateral or bilateral exercises. Unilateral bicep curls use one arm at a time, such as in hammer curls. Each hand holds a dumbbell, so each arm receives an equal amount of resistance to lift through the exercise. Both your right and left arms will receive the same strength benefits. A bilateral exercise uses both arms at the same time, such as in a barbell preacher curl. The drawback to this exercise is that your stronger arm may lift more of the resistance and your weaker arm will simply follow the bar as it is lifted. Use a concentrated effort when performing the preacher curl and aim to use both arms equally.
- American Council on Exercise: Standing Dumbbell Hammer Curl
- Manual of Structural Kinesiology; Clem W. Thompson, Ph.D.