Cross Jack
What Is the Cross Jack?
Cross Jack is a compound exercise that primarily targets the calves, hips and shoulders while conditioning the heart and lungs. It is a beginner-level movement that changes the familiar Jumping Jack in two ways: the arms stay at shoulder height and cross in front of the chest instead of swinging overhead, and on the inward jump the legs cross, one foot in front of the other, instead of landing together. The leading side switches on every rep.
Like the standard jack, it is a no-equipment way to raise the heart rate in a small space, which makes it a common choice for warm-ups, circuits, interval sessions and home workouts. The crossing pattern adds a coordination challenge, because the arms and legs have to cross and open together while the lead side keeps alternating. That makes it a useful way to add variety for clients who find plain jumping jacks too easy to do on autopilot.
The work is spread across the body. The calves absorb and push off every landing. The outer hip muscles drive the legs apart, and the inner thigh muscles pull them back in and across the midline, a wider inward range than a feet-together jack asks for. In the upper body the deltoids hold the arms up at shoulder height for the whole set, while the chest pulls them across and the rear shoulders open them back out.
Cross Jack suits beginners and general fitness clients who can already keep a steady rhythm with a basic jumping jack. Because the arms never go above shoulder height, it is also an option for clients who find the overhead swing of a standard jack uncomfortable. Anyone who struggles with the coordination can learn the pattern by stepping the feet out and across without jumping, then add the hop once the timing feels natural.
Muscles Worked
- Gastrocnemius (Lateral Head)
- Primary
- Gastrocnemius (Medial Head)
- Primary
- Soleus
- Primary
- Adductor Longus
- High
- Deltoid
- High
- Gluteus Medius
- High
- Tensor Fasciae Latae
- Medium
- Vastus Lateralis
- Medium
- Vastus Medialis
- Medium
Instructions
- Stand tall with your feet wider than your hips and your arms straight out to the sides at shoulder height, palms facing down.
- Brace your abs lightly, soften your knees and keep your weight on the balls of your feet.
- Jump and bring your legs in, crossing your right foot in front of your left so your shins cross and each foot lands on the opposite side.
- At the same time, swing your arms in and cross them in front of your chest at shoulder height, right arm on top.
- Land softly on the balls of your feet with your knees slightly bent, keeping the feet clear of each other.
- Jump straight back out to the wide stance as your arms open back out to the sides at shoulder height.
- On the next jump in, cross your left foot in front and your left arm on top.
- Keep alternating sides at a steady rhythm, torso upright and eyes forward, breathing steadily for the planned reps or time.
Common Mistakes
Crossing the same side every rep
Leading with the same foot and arm every time loses the alternating pattern, so switch which side crosses in front on each jump in.
Crossing the feet too deep
Crossing so far that the feet land in a line or touch makes it easy to clip a foot and roll an ankle.
Landing with stiff knees
Locking the knees on landing sends the impact into the knees and shins instead of letting the legs absorb it.
Landing on the heels
Dropping onto the heels jars the joints, while landing on the balls of the feet keeps the movement soft and springy.
Letting the arms drop
Arms that sag toward the hips lose the shoulder work, so keep them at shoulder height as they open and cross.
Arms and legs out of sync
The arms should cross as the feet cross and open as the feet open, not a beat behind.
Injuries
Cross Jack is a low risk exercise when performed with proper technique. As with any jumping jack, every rep is a landing, so the calves, Achilles tendons, shins, ankles and knees absorb dozens of small impacts in each set. The crossed landing adds one risk of its own: crossing too deep or losing the rhythm can make the feet clip each other, which can roll an ankle or cause a trip.
Land softly on the balls of your feet with your knees slightly bent, and keep the jumps low, just high enough to switch the legs. Cross the shins only far enough that each foot lands clear of the other, on the opposite side. Work on a clear, non-slip floor in supportive shoes, and keep the arms relaxed at shoulder height rather than flinging them hard across the body.
To regress, step instead of jumping: step one foot out to the side, then step it back across in front of the other foot as the arms cross, alternating sides. A basic Jumping Jack or Marching in Place also works while the rhythm or the joints need time. Progress by lengthening the work interval or picking up the pace, not by jumping higher.
Stop if you feel sharp pain in the heel, Achilles, shin or knee, if an ankle gives way, or if you feel dizzy, faint or unusually short of breath. Anyone with plantar fasciitis, an Achilles problem or a recent lower-leg injury should use the stepping version until repeated landings are pain-free.
- Primary Focus
- Cardio
- Equipment
- Body weight
- Modality
- Cardio
- Difficulty
- Beginner
Alternative Exercises
Other Names for the Cross Jack
The Cross Jack is also known as:
- Crossover Jack
Frequently Asked Questions
- Q: What is the difference between a Cross Jack and a Jumping Jack?
In a Jumping Jack the feet land together and the arms swing overhead. In a Cross Jack the feet cross on the inward jump and the arms stay at shoulder height, crossing in front of the chest, with the lead side switching every rep. That makes it more of a coordination drill and keeps the shoulders working through the whole set.
- Q: Which foot goes in front?
Alternate them. Cross the right foot in front with the right arm on top, jump back out wide, then cross the left foot in front with the left arm on top.
- Q: Is there a low-impact version of the Cross Jack?
Yes. Step instead of jumping: step one foot out to the side, then step it back across in front of the other foot while the arms open and cross, alternating sides. It keeps the coordination and the side-to-side hip work without the landings.
- Q: Is the Cross Jack good for warming up?
Yes. A short, easy set raises the heart rate and takes the hips and shoulders through side-to-side movement, which makes it a good start to a session before lower-body, upper-body or agility work.
- Q: Can I do Cross Jacks if overhead arm movements bother my shoulders?
Often you can, because the arms never go above shoulder height. If crossing the arms at shoulder height is also uncomfortable, lower them or keep them on your hips, and have ongoing shoulder pain checked by a professional.