To have the best workout, you should do a proper warm-up. Research shows that a warm-up routine that elevates your core body temperature can significantly enhance your training performance due to increases in nerve conduction velocity — the speed at which nerve signals reach the muscles. (1)
A great warm-up should elevate your core body temperature, improve your range of motion, ease soreness from prior training sessions, and prime the system for the upcoming training session.
When selecting warm-up exercises, favor low-intensity exercises to loosen up your joints and muscles for the training session. Similarly, when selecting versatile exercises for your main workout, opt for movements you can add to your cardiovascular, plyometric, or strength training HIIT sessions.
If you want an exercise that can do both, look no further than the split jack!
The split jack is a jumping jack variation that tweaks how the upper and lower body limbs move.
In this article, we will dive into how to perform split jacks properly, the muscles worked, its benefits, and review its alternatives.
Whether you are aiming to improve your athletic performance, trying to tone your muscles, or losing weight, keep reading to learn all there is to know about this unique bodyweight exercise and how it can benefit you.
How To Perform Split Jacks
The split jack is typically done without weight. Follow the steps to execute the split jack properly and get the most out of the exercise.
- Starting position: Stand upright with feet directly under the hips and arms at the side.
- Assume a lunge position: Step forward to a split stance position with one leg positioned out in front of the body and the other extended behind with the knees partially flexed as if you were to perform a lunge. At the same time, raise one arm above your head with the elbow slightly bent and the opposite arm extended behind the torso. Ensure that the leg in front aligns with the arm raised above your head and the rear leg aligns with the arm behind the midline.
- The jump & switch: In one swift motion, extend the hips and knees, jump, and switch the leg and arm positions.
- The finish: Land with a flat front foot and an elevated heel on the back foot to complete the repetition. Switch between sides for the recommended reps.
Split Jack Tips
Now that you know how to perform the split jack exercise properly, practice the technique to drill the movement. But, while doing so, be sure to keep these tips in mind, as they will help you improve your workout performance and get the most out of the exercise while reducing the risk of injury.
- Maintain a consistent rep cadence: Although it may not seem like it, the split jack exercise is a form of plyometric exercise. Plyometric training is a form of jump training and is a more advanced exercise technique that involves quick and explosive muscle contractions to propel the body up into the air. These are great ways to develop strength and power, but need to be progressed gradually. You can do so by sticking each landing on the split jack to start, and over a few training days, you can begin to increase the speed at which you perform them. This way, the muscles, tendons, and ligaments can acclimate to the forces involved.
- Maintain balance over the midfoot: When performing the split jack, the foot position is vital to maintaining balance and putting you in the best place to transfer into the next repetition. To maintain balance as you perform split jacks, focus on keeping the body weight centered in the midfoot of the front foot and the balls of the feet of the back foot, allowing for the force created by the lower body to be pushed into the ground properly to propel yourself in the air.
- Don’t walk a tightrope: Now that your body weight is centered correctly on both feet, it’s essential to maintain adequate distance between each foot. You can imagine how difficult it is to walk heel to toe, but now toss in a high heart rate and constant movement. To avoid disruptions in your set, maintain roughly a 4-6 inch space between each foot for stability.
- Use In Aerobic Exercise and HITT (High-Intensity Interval Training): The split jack is more than a warm-up exercise. It is excellent for aerobic and HIIT training. Additionally, you can use them as a stand-alone exercise in HIIT interval workouts such as Tabata. It involved performing a 20-second AMRAP (as many reps as possible) set, followed by a 10-second rest for eight rounds or four minutes.
- Add external resistance training: After mastering the movement, you can use external load to make the exercise more challenging. You could hold dumbbells in both hands or wear ankle weights to challenge lower body muscles. You can also use a weighted vest to free up the arms and legs.
Benefits of Split Jacks
Now that you are well versed on how to perform the split jack and equipped with expert tips to progress the movement effectively and safely, let’s dive into the benefits of the exercise and why they should be in your repertoire of exercises.
No Equipment Required
The most significant benefit of the split jack is that it is a bodyweight exercise. One of the biggest hurdles that can negatively impact the success of someone’s fitness journey is their access to a gym — whether that be the cost of a gym membership or lack of time to get to the gym.
Fortunately, exercises like the split jack only require your body weight and some clever programming to get a great workout.
Another great feature of the split jack exercise is that it is relatively simple to perform compared to other exercises and does not have a significant learning curve. Conversely, suppose you were to select an exercise like rowing. In that case, you must invest the time in learning how to row correctly to get the most out of the training, in addition to avoiding injury and overuse of the lower back or arms.
You can master the movement mechanics of the split jack in a few minutes, and after some practice repetitions, you will be up to speed to put it in either your workout routine or warm-ups.
Full Body Exercise
The split jack is an incredibly effective full-body exercise. Full-body, multi-joint compound movements are excellent for improving health and fitness. Not only because they train nearly the entire body and therefore use the most amount of muscle mass to burn calories, but because of what happens inside of the body hormonally.
When the entire body is used during high-intensity exercise, it increases the production of hormones like testosterone and human growth hormone, which play considerable roles in improving performance, building muscle, burning fat, and driving weight loss. (2)
Most people lose fast-twitch muscle fibers with age. These muscle fibers are responsible for quick and explosive movements like sprints and jumping. As people age, the need to sprint and jump may diminish, but there is still a power component to many everyday tasks, such as standing up from a chair or climbing stairs. Maintaining this quality is vital to sustaining independence and function.
The split jack can be an excellent, low-risk way to incorporate explosive movement into programs for older adults or those who want to maintain their power as they age.
Drawbacks of Split Jacks
These are the disadvantages of this exercise:
Limited Scope of Adding Resistance
The split jack lacks loading capabilities. Once you have mastered this movement from a coordination standpoint and have added some resistance to the arms and legs, there is a point of diminishing returns. This is because you can only lift so heavy doing split jacks, and anything more than light to moderate weights may significantly alter the movement mechanics. This makes this exercise suboptimal for strength training.
However, the split jack is an excellent option for a warm-up exercise or conditioning movement to get the body ready for more intense activities.
May Not Be Joint Friendly
Since the split jack is primarily a plyometric exercise, it may not suit you if you have joint pain, particularly in the ankles, knees, hips, or lower back.
Requires Optimal Mobility
Since the split jack requires both arms to go directly overhead and each leg to extend back beyond the torso, it requires decent mobility. In some instances, especially when the exercise is done under fatigue, you may unknowingly compensate through other joints to complete a repetition, leading to overuse injuries and pain over time.
For example, extending through the lower back to raise your arms overhead due to restricted lat or thoracic spine mobility.
But, with some careful attention to what you need specifically in your workout routine, you can modify the range of motion to make split jacks work for you to reap its benefits.
Muscles Worked During Split Jacks
The split jack incorporates many muscle groups. Below are some of the muscles working during the split jack movement.
Lower Body Muscles
- Hip Flexors
Upper Body Muscles
- Lower Trapezius
- Serratus Anterior
- Levator Scapulae
- Rectus Abdominis
- Transverse Abdominis
Variations & Alternatives
Here are some split jack variations to add to your exercise arsenal:
It is a well-known exercise that has many of the same benefits as the split jack.
How it’s different:
Conventional jumping jacks are a frontal plane exercise that calls for the arms and legs to move into abduction or away from the body laterally.
The seal jack is very similar to the jumping jack as it calls for the limbs to move in the frontal plane.
How it’s different:
The seal jack involves moving the limbs away from the body laterally, such as in jumping jacks. Still, it has key differences in that instead of the arms raising above the head, they stay below the shoulder level, move backward into horizontal abduction, and then come together at the top of the movement.
The squat jack is a split jack alternative that emphasizes the lower body.
How it’s different:
The squat jack comprises keeping the arms tucked in towards the chest and the exerciser to maintain a half squat position as the legs move away from the body and back to the center.
How do I make split jacks easier or harder?
To make split jacks easier, slow your rep tempo. Begin with slow and controlled movement to ensure proper form. To make it harder, you can increase the speed, perform them as a part of a circuit, or add resistance.
How far apart should my feet be?
A good rule of thumb is to position the feet in a split stance that would mimic a lunge exercise. If you need to get more familiar with a lunge, two steps forward should be enough distance. Horizontally, anywhere from 4-6 inches should suffice.
What are some common mistakes of split jacks?
The most common mistakes are lining the feet up too narrow, not lunging back far enough, not completing each rep with one arm overhead, and not maintaining the weight in the midfoot of the front foot.
If you are looking for a simple yet effective exercise that you can use in your warm-ups or your actual workouts, then the split jack is perfect for you.
The split jack requires little time to master, can easily fit into your warm-up or full-body workout routine, and can be used in LISS and HIIT workouts.
People of all fitness levels can perform the split jack. It is perfect if you want to warm up quickly and start moving or are trying to maintain your strength and speed with new plyometric exercises.
Always prioritize quality over quantity and progress your workouts slowly over time to avoid injury.
Now, with that said, get to the gym and start training!
Fitness Volt is committed to providing our readers with science-based information. We use only credible and peer-reviewed sources to support the information we share in our articles.
- Todnem K, Knudsen G, Riise T, Nyland H, Aarli JA. The non-linear relationship between nerve conduction velocity and skin temperature. J Neurol Neurosurg Psychiatry. 1989 Apr;52(4):497-501. doi: 10.1136/jnnp.52.4.497. PMID: 2738592; PMCID: PMC1032299.
- Gharahdaghi, N., Phillips, B. E., Szewczyk, N. J., Smith, K., Wilkinson, D. J., & Atherton, P. J. (2021). Links between testosterone, oestrogen, and the growth hormone/insulin-like growth factor axis and resistance exercise muscle adaptations. Frontiers in Physiology, 11, 621226.