For a jump rope to be what you need to get the maximum fitness advantage out of this fun tool, it must be the right length. Standing on the rope at the middle and extending it upward, the handle should reach to just under your armpit. If you don’t have a jump rope to measure with, note that the correct size rope is usually about three feet longer than the user is tall. Thus, if you are 5 foot, 6 inches tall, you’ll need a jump rope about 8.5-feet long. Some ropes are easily adjusted for length, so you don’t have to be as careful when making an initial purchase. Others have different length ropes that can be attached to the same handles, making them useful for several different users of different heights. Note that if you decide to shorten your rope, be careful—a shorter rope leaves you less room for error when jumping.