Jump rope movements are an easy cardio movement to do when you're limited on equipment or gym access. A jump rope can be easily packed in a carry-on bag or suitcase if you're traveling as well. There's no excuse not to get your workout in even when you're on vacation!
Single unders are named as such because the jump rope passes under the feet a singular time during each jump. if you ever did Jump Rope for Heart in elementary school, then you're probably very familiar with this movement!
Start by holding the jump rope handles slightly in front of your hips. Keeping your upper body upright and your body in a straight line, jump your feet a few inches off of the ground.
Rotate the wrists so that the rope passes under your feet one time with each jump. Each time the rope passes under the feet and you don't trip, that's one completed rep.
Single unders are a great movement to incorporate into HIIT-style workouts. See how many single unders you can complete without tripping. Or set a timer for a minute and see how many completed reps you can get within that time period.
For a more advanced movement, check out the double under.