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Quads

Seal Jack

The Seal Jack is a plyometric exercise with no equipment for your quads. Share of the load in the Zulta muscle model: calves (gastrocnemius) 14%, quads (vastus lateralis) 11% and gluteus maximus 9%.

Level: BeginnerEquipment: Bodyweight

How to do it

  1. Stand tall with feet together and arms straight out in front at shoulder height, palms facing each other.
  2. Jump the feet out wide while opening the arms out to the sides.
  3. Land softly on the balls of the feet with the knees slightly bent.
  4. Jump the feet back together while clapping the hands in front of the chest.
  5. Repeat at a steady pace for 30 to 60 seconds.

Tips

  • Open the arms until you feel the chest stretch and the shoulder blades squeeze.
  • Keep the arms at shoulder height the whole time.

Common mistakes

  • Letting the arms drop below shoulder height.
  • Landing heavily on the heels.
  • Arching the lower back as the arms open.

Muscles worked by the Seal Jack

  • Calves (gastrocnemius) Primary14%
  • Quads (vastus lateralis) Primary11%
  • Gluteus maximus Secondary9%
  • Hip flexors Secondary9%
  • Gluteus medius Secondary9%
  • Calves (soleus) Secondary9%
  • Adductors Secondary7%
  • Side delts Minor7%
  • Quads (rectus femoris) Secondary7%
  • Hamstrings (biceps femoris) Minor5%
  • Quads (vastus medialis) Minor5%
  • Tibialis anterior Stabilizer4%
  • Upper abs Stabilizer4%

Share per muscle in the Zulta muscle model. The model spreads the load of one rep over 40 muscles, based on EMG and biomechanics research.

Arms and legs out to the side. Quick footwork drills and skips: the calves, quads and hip flexors cycle the legs, the glute medius handles every change of direction.

Seal Jack alternatives

Same equipment

Different equipment

Make it harder

Frequently asked questions

What muscles does the Seal Jack work?

Mainly the calves (gastrocnemius) and quads (vastus lateralis). The gluteus maximus, hip flexors, gluteus medius, calves (soleus), adductors and quads (rectus femoris) assist.

Is the Seal Jack good for beginners?

Yes. The Seal Jack is rated beginner in the Zulta library: the technique is easy to learn with a light weight.

What is a good alternative to the Seal Jack?

For example the Jumping Jack, Carioca and Lateral Shuffle. They train mostly the same muscles.

How do you make the Seal Jack harder?

Add weight or reps, or move on to the Carioca and Cone Drill (5-10-5 Shuttle).

Log your sets in Zulta

Zulta tracks your sets, weights and muscle load next to your running, riding or Hyrox training. The app opens soon.

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