I think running has lot of benefits, but also has disadvantages. If you have poor mechanics or shoes, you can cause more long term issues. Further, for tennis players who are already subjecting their knees to lot of impact on hard courts, running on another hard surface seems counter productive. You play soccer/hockey as midfielder or a striker, u are going to easily run 2-3 km every day during scrimmage. Why would you subject them to 10k 4-5 times a week?
https://www.runnersworld.com/news/a2084 ... n-a-match/As for recreational tennis players? The distances are about the same. In 2020, Fitbit reported that according to their user data, an hour of singles tennis generates around, on average, 10,680 steps, while an hour of doubles tennis generates, on average, 7,980 steps. That’s an equivalent of about 4 to 5 miles of running and 3 to 4 miles respectively depending on your stride length.
I would not do separate long distance running for any of the sports mentioned as all of this athletes will build up lot of endurance just from playing this sport. My endurance level improved dramatically after playing field hockey for an year. If they need to improve their aerobic activity, perform cross training (that does not involving pounding your knees). I would potentially look at swimming as a much better cross training sport for all of the sports mentioned above rather than running ,