Like a Ninja!
Ty Santiago's family runs a gym that has a ninja training obstacle course, so when there is a junior competition announced for the National Ninja Champion reality show, it attracts several young people. Kevin has been doing boring workouts after his bout with cancer, and he's interested in ninja training even if his mother wouldn't let him. Mackenzie loves the show but is more of a blogger than an athlete, but her dads are okay with her competing. Izzy's family is big on running, but she's more into parkour, and when she accidentally breaks a window with a skateboard, she ends up running at the gym as punishment. JJ comes to the gym because his father is helping to construct kid sized equipment, He doesn't like to draw attention to himself, but he begins to enjoy the training. The group is lucky to have Tracy, a former NNC competitor, to help train them, and they all make great progress. There are some obstacles, like soccer team try outs for Ty being on the same day as the NNC taping, but the kids all learn to work together to accomplish their goals. How will the five fare in competition? Since a sequel, The Fastest Finish, comes out 15 January 2019, it's safe to assume that they all do fairly well!
This is a short book, so the five main characters develop slowly. There is just enough drama with parents to strike the right note. Kevin's mother causes the biggest problems, since Kevin has to lie to her in order to train, but she eventually sees his point that he has recovere from cancer and doesn't need to be coddled. Izzy's family is a bit more problematic-- her father's repeated assertion that "Fitzgeralds run" isn't very helpful to Izzy, and the fact that her family chooses to run a 5K instead of watching her competition is concerning. Mackenzie interacts positively with her dads as well as her birth mother, but hopefully more information will be relayed in future volumes.
There are very few middle grade books involving actual ninjas, and not very many about extreme sports, unless you count some of Matt Christopher's twenty five year old BMX bike books. Pam Withers did some good outdoor adventure stories about ten years ago, but Junior Ninja Champions is a rather singular book that will be welcomed by readers who would rather be out rappelling down a cliff or riding skateboards down stair cases!