All CHERUB agents are expected to stay in top shape. There are two particular targets behind CHERUB fitness training:

1) The ability to run a long distance at speed, which could be essential where it is necessarily to escape a dangerous situation.
 
2) Strength. Few people realise that basic resistance training with body mass (e.g. push-ups) and weights can quickly double a person’s strength. While a twelve year old boy will typically possess less than a third of the strength that he will as an adult, two months strength training will quickly raise this to two thirds. Combined with skilled application of martial arts techniques, most CHERUB agents have the strength and ability to fend off a fully grown adult assailant.

All cherubs must undergo quarterly medicals, where they are given dietary advice and a set of training targets. They are allowed to pick from a range of fitness programs. Football and rugby squads are among the most popular, others prefer more solitary activities such as running or working out in the gym.

Any agent who misses their fitness target without an excuse (such as a long mission or an injury), will be assigned to a tough fitness program under the direct supervision of a CHERUB training instructor. This compulsory training is exceptionally harsh and very few agents allow their fitness level drop below an acceptable level more than once.