This applies to Ice hockey, which is obviously a very physical sport.
cdn3.sportngin.com/attachments/document/8a0b-1766565/USA_Hockey_Transgender_Athlete_Eligibility_Policy.pdf
To compete in most forms of girls hockey, including school teams, a boy just needs a letter from parent & health care provider. However for the highest Tier 1, and Tier 2, 1 year of hormone suppression is required
NBs are included, so you don't have to identify as a girl to go on the girls team. If you can find a doctor who studied at the school of woke bullshit and hurt feelings, rather than a medical school of hard science and data, and he signs you off as NB, then you can also play with the girls.
For adult hockey, a male can identify onto the women's team without any testosterone suppression - you just need to identify as a lady.
In order to make transgender players feel comfortable, USA hockey advises that you should ban everyone on a team that has a transgender player from taking their clothes off - players should arrive in a base layer, and if they need to take their clothes off they should do it in a private room only.
You are also advised that if you have switched genders you won't be able to switch again for at least another three years! This may discriminate against people who identify as gender fluid!