A jump rope is a rope turned under the feet in rhythm — cheap, portable and scalable from beginner bounce steps to double-unders.
A systematic review with meta-analysis in the Journal of Sports Sciences (2022) pooled trials of jump rope training in young participants and reported improvements in cardiorespiratory fitness, coordination, speed and jumping performance compared with control conditions, across relatively short programmes of a few weeks. Rope skipping is also a repeated-impact activity — the same quality that makes it a plyometric stimulus — so published programmes progress duration and surface gradually. It remains a staple of the published boxing and combat-sport conditioning literature for footwork and rhythm.