Jumping Jack is a full body workout that improves cardiovascular health and fitness. These not only target the major muscle groups, but also strengthen the bones. However, jumping jacks involve a lot of jumping, which results in a lot of force being applied to the lower joints of the body. This is why jumping jacks are associated with an increased risk of injury, especially to the knee and ankle joints.
To avoid such risks, it is important to focus on strength and conditioning first. Strength and conditioning involves exercises dedicated to building muscle and endurance. These include squats, lounges, bridges, push ups, dead bugs and deadlifts.
However, if you still want to get involved in jumping jacks, start without jumping. This is called a modified jack.