Schmidhofer, Leser and Ebert (2014) investigated the playing style of kids at the age 9-12 years playing tennis on different scaled courts after the ITF's Tennis10s system (ITF, 2016) and compared the structure in kids' tennis to the adult (ATP) level. They found a severe problem at the transition from the Orange stage (U9) to the Green stage (U10), which can mainly be reasoned by the enlargement of the court from a small-sided field to the full sized court. Aware of this problem, Ebert (2012) introduced an intermediate stage between Orange and Green, the so called Lime Court (stage). Summarised, the Lime Court enables children to play more similar to elite players than the Green Court. Thus, Lime closes the existing gap between the Tennis10s stage Orange and Green and should be used for ten years old tennis players in order to properly develop their playing skills.