The cross-over jack is a variation on the jumping jack, a popular calisthenics exercise used to improve overall conditioning. The difference between the jumping jack and the cross-over jack is that with the latter, the feet don't just come together each rep, they cross over each other. It's a great way to add variety to your warm-up or conditioning work.
Works the abductors and adductors more than traditional jumping jacks
Burns calories and elevates heart rate
Good for warm-up sets or as a way to keep heart rate elevated between sets and exercises
Raises core temperature and mobilizes shoulders and hips before lifting or sports