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Pencil Jacks Exercise: How To, Muscles Worked,…

There are many different ways to improve your current exercise routine. What about doing pencil jacks, what will the effects be?

Pencil jacks are a variation of jumping jacks where you do a little jump with your arms straight up in the air between each jumping jack. This makes the exercise focus slightly more on the front part of your shoulder muscles and calves but it also makes doing the exercise at high speeds a lot more awkward.

Pencil jacks are an exercise that can be useful as a warmup or to improve coordination. For other fitness goals, there are many better exercise options. You do get some cardiovascular and muscle engagement when doing pencil jacks but generally not enough to see much progress.

Whether you should add pencil jacks or alternatives to your routine depends on things like your personal situation, personal preference, and training goals.

How to do a pencil jack

To do a pencil jack take the following steps:

  1. Stand up straight with your arms beside your body.
  2. Jump in the air and move your legs sideways and outward. Move your arms sideways and upward.
  3. Land with your feet wide apart and your arms pointing upward. You generally want to have your legs slightly bent so you can better deal with the impact of landing.
  4. Jump back into starting position.
  5. Jump straight up a small amount while moving your arms forward and upward. Ideally your arms are vertical at the top of the jump movement and back down when you land.
  6. Land with slightly less than stretched legs into starting position.

If you want to do pencil jacks at higher speeds you will have to get used to the movement. You can start at a very slow speed and build up from there.

How you want to land depends on what body parts you want to absorb the shock. For most people landing on the front of your feet with your legs slightly bend and feet slightly tilted will be the most comfortable. Also try to keep your body straight up during the exercise.

You can make pencil jacks harder for your leg muscles and cardiovascular system by wearing a weighted vest.

How to do a pencil jack

Pencil jacks muscles worked

With any exercise you will almost always make a variety of different muscles work, especially with a compound exercise like pencil jack. Even so, there are a few muscles that will have to work the hardest for moving and keeping your body in position.

Pencil jacks work a variety of muscles including inner thighs, outer thighs/hips, calves, glutes, quadriceps, hamstrings, core, and shoulders.

Compared to regular jumping jacks, pencil jacks focus slightly more on the front part of your deltoids (main shoulder muscle) and calves. At the same time you spend less time engaging your inner and outer thights.

Exercise beginners may be able to build some muscle with pencil jacks. However, this exercise will likely stop being challenging enough soon to see a lot of muscle growth and strength progress.

Any progress is a nice addition but if you are serious about building muscle you likely want to turn to resistance training exercises.

Pencil jack exercise benefits

This exercise will likely not be the fastest way to your fitness goals but pencil jacks can still offer you some helpful benefits. Some of the most important ones include:

  1. Can help with losing weight: Doing pencil jacks likely requires more energy than your regular daily activities. Extra muscle mass also helps with burning more calories. Both of these aspects can help with, but are no guarantee for, weight loss.
  2. Stronger muscles: While the standard version of pencil jacks is mainly a cardiovascular and coordination exercise, they can also help you strengthen muscles to a certain extent.
  3. Improves mood: Exercise like pencil jacks promotes the release of substances that help you feel good.
  4. Balance and coordination: Balance and coordination are fitness skills that can be improved by challenging them. Pencil jacks can help you with this.
  5. No equipment or location required: Since pencil jacks are a bodyweight exercise you don’t have to invest in equipment or be in a specific location.
  6. Improves sleep: Exercise like pencil jacks can improve the quality and duration of your sleep which in turn offers many important benefits.
  7. Slows down aging: Pencil jacks won’t influence how many days have passed since you were born. However, exercise can slow down the progress of certain aging markers that are correlated with negative health effects.

While inevitably many workouts are better for some of these benefits than pencil jacks, it is amazing that you can get so many important benefits from adding one activity to your routine.

Potential risks

The main thing to keep in mind is that pencil jacks can be hard on body parts like your ankles, knees, hips, lower back, and shoulders even if you implement the right technique.

If you are sensitive or weak in these body parts you may need to do other strengthening exercises first. Especially if you have any ankle or shoulder pain, you may want to talk to your primary care provider before implementing pencil jacks into your workout routine.

If you feel pain in any body parts it may be a sign you are overdoing it. In that case, you may need some rest, better lifestyle habits, a less intense workout schedule, or it may be a sign that pencil jacks are not (yet) for you.

Pencil jack exercise alternatives

While pencil jacks can be a good addition to your workout routine, there are also some alternatives available for training similar aspects of your physical health. Some of these pencil jack exercise alternatives include:

  • Jumping jacks
  • Side shuffles
  • Agility drills
  • High knees
  • Weighted leg adductions or abductions
  • Squats
  • Running

Which one of these options is the best depends on things like your personal situation, training goals, the equipment you have available, etc.


Many people will benefit from adding pencil jacks with the right technique to their routine as a warmup or coordination training exercise. For both cardiovascular and muscular training other exercise options may be better.

Another thing you need to remember is that doing pencil jacks can be hard on body parts like your ankles, knees, hips, and lower back, even if you implement the right technique.

If you are sensitive in these areas you may need to do other strengthening exercises first. Especially if you have any ankle or shoulder pain, you may want to talk to your primary care provider before doing more pencil jacks.

Also keep in mind that consistency is an important factor for any workout plan. The more you love the exercise you do the easier it becomes to do it consistently. If doing pencil jacks is a workout you love, you can consider implementing this exercise anyway. If not other exercises likely offer more benefits.

If you do decide to implement more pencil jacks make sure you give your body enough nutrients, rest, and sleep to repair and grow your muscles.