How to Do Jammers: Proper Form, Variations, and Common Mistakes

Verywell / Ben Goldstein 

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The barbell jammer exercise is an intermediate to advanced, upper-body explosive move that builds strength in the shoulder muscles and 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.

Also Known As: Barbell jammer press, barrel jammer, single-arm jammer, hammer jammer, landmine thruster, shoulder jammer

Targets: Deltoids, pectoralis major and minor, triceps, and abdominals

Equipment Needed: Barbell and weight plates

Level: Advanced

How to Do a Jammer

Place 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.

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 will not move during the exercise. 

Get into a split squat stance, with one foot in front of the other. The raised end of the barbell should be at shoulder height. 

  1. Take the barbell in one hand by cupping it with an overhand grip. The other arm can rest at your side.
  2. Push the bar away from your body until your arm is extended.
  3. 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. 

Benefits of Jammers

The 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. 

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.

Other Variations of Jammers

You can perform this exercise in different ways to meet your skill level and goals.

Jammer With a Squat

Verywell / Ben Goldstein 

Adding a squat turns jammers into a full-body move that you can include 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. 

Set up as you would for a basic jammer, with a barbell secured in a corner or weight plate. Stand in a squat position with your feet slightly wider than shoulder-width apart.

  1. 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.
  2. Position the bar in front of your chest, with your hands cupped around the unanchored end of the bar, under your chin. Your shoulders should be down and back, chest lifted, and gaze straight ahead.
  3. Hold the end of the bar and 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.
  4. Press the bar overhead as you approach a standing position 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 on your toes.
  5. 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.

Explosive Jammers

Adding explosive movements to the jammer can help build power and strength. This version is more advanced, so make sure you have fully nailed the original version for a few weeks before progressing.

To perform this variation, follow the steps for a jammer with a squat. But once you lift the bar overhead, do not pause. Instead, immediately lower the bar and your body by squatting to the starting position and then powerfully pushing back up.

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 Engaging Core Muscles

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.

Safety and Precautions

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 barbell jammer exercise is generally safe 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.

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

Try It Out

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

2 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Thornhill K, Beggs M. The rehabilitation of the rugby shoulder: A proposed approach to management. In: Wilson J, Southorn N, Porter S, eds.: A Comprehensive Guide to Sports Physiology and Injury Management: An Interdisciplinary Approach. Elsevier Health Sciences.

  2. Retchford TH, Crossley KM, Grimaldi A, Kemp JL, Cowan SM. Can local muscles augment stability in the hip? A narrative literature review. J Musculoskelet Neuronal Interact. 2013;13(1):1-12.

By Sara Lindberg
Sara Lindberg, M.Ed., is a freelance writer focusing on health, fitness, nutrition, parenting, and mental health.