Curls primarily target the biceps but they do work your forearms as a secondary muscle. How intensely your forearms are worked by curls depends on the type of curls you do. Standard dumbbell and barbell curls work the forearm muscles slightly. Reverse curls provide a far more intense forearm workout. You can choose different exercises to focus on building mostly your biceps, isolating your forearm muscles, or working both muscle groups at once.
Why Do You Have Sore Forearms After Bicep Curls?
Your forearms may begin to burn during curls because the muscles in your forearm are responsible for gripping the weight you are curling. If you are curling with a standard palms-up grip, the flexor muscles in your forearm are tensed throughout the exercise. These muscles are responsible for keeping a strong grip on the weight.
- Your forearm muscles are responsible for gripping and holding heavy weight during curls.
- Standard curls (with palms facing upward) primarily work the flexor muscles of the forearms.
If you are lifting a very challenging weight—or if you are new to weightlifting—it’s common to have sore, tired forearms after doing curls. All workouts that require a strong grip, such as deadlifts and pull-ups, you will provide a forearm workout.
Are Curls a Good Forearm Workout?
Curls are not the best forearm workout, simply because building forearm muscle is not the main goal of curls. Your biceps are the main target of curls. Typically, your biceps muscles will become exhausted well before your forearms get a complete workout from curls. So, while curls are not bad for forearms, they won’t help you gain significant forearm muscle.
- Your forearms are only used as a secondary muscle during curls.
- Biceps are the primary muscles used for curling.
- When curling, your biceps will get a full workout before your forearms are exhausted.
- Traditional curls will build bigger biceps, but provide small increases to your forearm size and strength.
Unlike having a sore chest after doing curls, sore forearms after curling does not mean you’re doing curls wrong. It simply means your forearms are working hard. Doing challenging curls can help build grip strength necessary for tougher exercises. Don’t worry, doing curls is one of the keys to correcting big forearms and small biceps.
How Do You Make Your Forearms Bigger with Curls?
If you want to do curls that build your biceps and forearms at the same time, add the reverse curl to your routine. As we covered in our comparison of reverse curls vs hammer curls, reverse curls are great for activating the brachioradialis and other forearm muscles. In order to do this lift:
- Grip your dumbbells or curl bar with your palms facing down (this “reverse grip” gives reverse curls their name).
- Begin with your arms extended straight downward—your palms should be facing your thighs in this starting position.
- Without moving your shoulders or upper arm, bend at the elbow to curl the weight upward until your elbows are fully bent.
- Slowly lower the weight to the starting position—this downward motion should take 3 seconds.
- Repeat for 3–5 sets of 8–12 reps for bigger biceps and forearms.
Although you will have to reduce your curling weight while doing reverse curls, you’ll get a far better forearm workout. Other curl variations target the biceps more than any other muscle. Reverse curls do a great job of working both the biceps and forearms simultaneously.
What Curls Do Not Work Forearms?
Hammer curls, concentration curls, and standard curls where you grip the weight with your palms facing up do not work your forearms much. You will only activate a few forearm muscles with these “standard” curling styles. That’s okay, because these exercises are designed for the biceps, not the forearms.
- Curling with a supinated grip (palms facing up) does not work the forearms effectively.
- Neutral-grip curls (palms facing inward) will not provide a significant forearm workout.
- For the biggest benefit to forearm strength, curl with your palms facing downwards.
If you want a curl exercise that leaves your forearms burning and exhausted, steer clear of palms-up or neutral grip (palms facing inward) lifting forms. Curling with your palms facing downward activates the highest percentage of forearm muscles.
What Exercises Build Forearms?
If you want to build big forearms, follow our guide to using hand grippers to increase forearm size. Performing dedicated forearm workouts with grip trainers and similar equipment will increase grip strength and forearm size efficiently. This way, you can use curls to work on your biceps, then use hand grippers to build what are considered big forearms.
- Performs reps and sets with hand grippers to build forearm strength, size, and definition.
- Your forearm muscles are responsible for your grip strength.
- Exercises that push your grip strength to its limits will build bigger forearms.
- Deadlifts, wide-grip pull-ups, and farmer’s walks are great for forearms.
In addition to using grip trainers, several other workouts will build your forearms. Deadlifts, pull-ups, farmer’s walks, and battle rope training all require a strong grip. Since your grip strength is determined by your forearm muscle, exercises that require you to grip challenging weights will always assist in forearm strength and growth.
Do Curls Make Your Forearms Bigger?
Curls do have some effect on forearm size and strength, but the type of curls you’re doing may not be effective for building bigger forearms. Here’s what you need to know:
- All curl variations work the forearms as a secondary muscle.
- Your biceps will get a better workout from curls than your forearms do.
- Curls can help build a small amount of forearm size and strength.
- Reverse curls are much more effective for building your forearms than other curl variations.
- Your forearms are responsible for your grip strength—challenging your grip will build bigger forearms.
- Use grip trainers, deadlifts, farmer’s walks, and wide-grip pull-ups to build bigger forearms.
So, curls are not a fantastic way to build bigger forearms, but some curl variations can provide a fairly good forearm workout. The best way to build bigger forearms is by training your grip with grip trainers. However, many foundational gym exercises will help build bigger, stronger forearms. So, although curls aren’t the best workout for your forearms, they will provide some benefits to forearm strength.