How to Do Jammers

Proper Form, Variations, and Common Mistakes

Jammers exercis

Verywell / Ben Goldstein 

Also Known As: Barbell jammer press, barbell jammers, single-arm jammer, hammer jammer

Targets: Deltoids, pectoralis major and minor, triceps, and abdominals. When combined with a squat, the quads, glutes, hamstrings, and calves are also targeted.

Equipment Needed: Barbell and weight plates

Level: Advanced

The barbell jammer exercise is an intermediate to advanced upper body explosive move that specifically builds strength in the shoulder muscles but also targets the triceps, chest, and core muscles. To a lesser extent, barbell jammers work the biceps and lats. When combined with a squat, jammers give your quads, glutes, hamstrings, and calves an excellent workout.

You can add the barbell jammer move to an upper-body workout, and more specifically, a shoulder workout. When using this as a pressing exercise to target the shoulders, make sure to use a lighter weight.

If you add the squat portion of the exercise, jammers become a full-body move that can be included with a circuit or overall total-body workout. When performed this way, you can add more weight since the powerful muscles of the lower body will be assisting with the movement. 

There are many benefits to this exercise. However, since it is considered an advanced move, working with a certified personal trainer, athletic trainer, or physical therapist can help you learn the proper technique, which will decrease your chance of injury and increase the effectiveness of the exercise. 


The barrel jammer exercise targets the muscles in your deltoids, pectorals, triceps, lats, and core. Since the exercise requires you to maintain a neutral spine, you will need to engage the muscles in your core, including the deep abdominal muscles, otherwise known as your transverse abdominis.

When performing the barbell jammer as a press only, the move is considered a strength exercise, specifically for the shoulder muscles. To execute the move, you can press with one arm, or both at the same time. A single-arm jammer allows you to isolate each side individually, which can help with muscle imbalances. It also requires your core muscles to work on overtime to assist with balance and stability. 

But if you want to turn this exercise into an explosive, power-based move for the entire body, add the lower body by squatting before pressing the bar. This version is an excellent sport-specific move to add to any athletic training program.

To make this move more challenging, you can add a squat before you press. This increases the intensity of the exercise and makes the move more explosive, which is a great way to train for power. 

By adding a squat to the jammer exercise, you can strengthen your quads, glutes, hamstrings, and calves. This helps to stabilize the hips, which decrease low back pain, improves posture, and helps you perform better in fitness and sports-related activities.

Step-by-Step Instructions

There are two versions of this exercise: the traditional shoulder-press jammer and the full-body jammer with a squat. The first set of directions pertain to the traditional barbell jammer press exercise, followed by the steps to include a squat. Do not add weight until you are comfortable with the form. When you’re ready to add plates to the bar, place the weight on the end of the barbell that is not anchored. Make sure to secure the plate with a barbell collar so it does not move during the exercise. 

Jammer Press 

  1. Start by placing the end of a barbell in a corner so it will not move. Alternatively, you can place a weight plate on the floor—against the wall, so it doesn’t move—and put the end of the barbell in the hole. This will anchor the bar.
  2. Get into a split squat stance, with one foot in front of the other. The barbell should be at shoulder height. 
  3. To begin, take the barbell in one hand by cupping it with an overhand grip. The other arm can rest at your side. Push the bar away from your body until your arm is extended. Pause at the top and lower the bar back to the starting position.
  4. Continue until you reach the desired amount of reps on one side, then switch sides. 

Aim for 10 repetitions on each side. Complete two to three sets for 20 to 30 reps total on each side — rest 30 seconds between sets. 

Jammer With a Squat

  1. Start by placing the end of a barbell in a corner so it will not move. Alternatively, you can place a weight plate on the floor—against the wall so it doesn’t move—and put the end of the barbell in the hole. This will anchor the bar.
  2. Stand in a squat position with your feet slightly wider than shoulder-width apart.
  3. Squat down and grab the unanchored end of the bar with both hands in a closed grip. Make sure your body is at a 45-degree angle to the bar.
  4. With your hands cupped around the unanchored end of the bar, position the bar in front of your chest, under your chin. Your shoulders should be down and back, chest lifted, and gaze straight ahead.
  5. Holding the end of the bar, stand up by shifting the weight from your heels to your toes and drive your hips forward to straighten your legs. The barbell will stay in front of you.
  6. As you approach a standing position, begin to press the bar overhead to make a shoulder press movement. Keep your back straight, and avoid arching the lower back. To fully extend your arms and press the bar overhead, you will rise up on your toes.
  7. Pause at the top of the movement, then lower the bar and your body by squatting to the starting position.

Aim for two to three sets of 10 repetitions each. Rest for 30 seconds between sets.

Common Mistakes

Many of the mistakes people make when performing the barbell jammer exercise can be corrected by working with a certified personal trainer. But if you’re learning the move on your own, look out for these common mistakes that can lead to injury or improper execution of the exercise.

Dipping or Arching Your Lower Back

Since the jammer exercise requires you to stand upright and press the weight above your head, maintaining a neutral spine with a strong lower back is essential to reducing the risk of injury to this area. It’s common to see people performing this move with a curve or arch in their lower back, which means they are not engaging the core muscles. To correct this, tighten your core prior to pressing the bar. 

Using Too Much Weight

The shoulders are not a large muscle group. If you are performing this move as a pressing exercise, keep the weight light, especially when starting. You can add more resistance if your lower body is involved, but even then, consider starting with the bar (and no weight) until you master the technique. 

Not Keeping Your Core Muscles Engaged

Having the weight out in front of you can cause you to fall forward, putting pressure on your lower back. To correct this, tighten your core muscles before pressing the bar. Your core muscles act as an internal weight belt that keeps your form tight and helps the entire area of your body stay strong. By engaging your core muscles, you can keep your lower back strong, which prevents it from dipping and adding strain to the erector spinae muscles.

Modifications and Variations

Not sure if you're ready to add weight to the jammer exercise? Ready to kick it up a notch and increase the intensity? No problem. You can increase or decrease the intensity and weight involved with this exercise to make it fit your fitness level.

Need a Modification?

If you are new to the barbell jammer exercise, it’s a good idea to perfect your form before adding weight. To start, use the lightest barbell in your gym, but make sure it is long enough to give you the leverage you need to target the shoulders. Once you master the technique, slowly add weight in the form of plates. Consider moving in 10-pound increments until you reach a resistance that is challenging, yet allows you to perform the move with proper form.

Up for a Challenge?

Once you master the barbell jammer, consider adding a squat to the move. By including the lower body, you increase the number of muscles recruited and set yourself up for a higher calorie burn. Doing a jammer with a squat turns this shoulder-pressing exercise into a full-body integrated movement.

To increase the intensity, and make the jammer with a squat more explosive, you can also speed up the pace of the move, which makes jammers more of a power-based exercise. Adding resistance will help you work on increasing strength.

Safety and Precautions

The barbell jammer exercise is generally a safe exercise for intermediate to advanced levels. That said, if you have issues with your shoulders, such as a previous or existing injury, pain in that area, or a reduced range of motion, this may not be the best exercise to add to your lineup.

Additionally, if you have neck pain, wrist pain, or low back pain, this exercise may be contraindicated. When performing the jammer exercise, make sure to pay attention and address any discomfort or limited range of motion you may experience during the pressing portion of the movement. If you feel any pain, stop the exercise and consult your doctor or a physical therapist.

Try It Out

Incorporate this move and similar ones into one of these popular workouts:

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