The rules
It is a community Top-Level Domain, it means that only members of the "community" will be able to register such domain names. Here is what the official eligibility requirements say:
Two types of conditions must be fulfilled for the right to register a .SPORT name. These are:
- community membership and
- the additional requirements that the registrant’s role in the Sport community, as well as the registrant’s use of the registered domain name, must be:
- generally accepted as legitimate; and
- beneficial to the cause and the values of Sport; and
- commensurate with the role and importance of the registered domain name; and
- in good faith at the time of registration and thereafter.
These conditions must always be fulfilled. The strength of the validation is kept in line with the importance of the underlying domain name based on the assumption that a typical user would reasonably make.
To facilitate validation, registrants are required to state their intended use of the registered domain name. A false statement of intended use is an indication of bad faith and can be the basis for the suspension of the domain name.

My opinion
Community TLDs are "community TLDs", it means that domain names are blocked from being registered by anyone. It is a good solution when a registry can easily be financed but it is a very bad one to install domain names onto a market, unless of course, if all sports organizations have already decided to use one (which I doubt that it is already the case). My true opinion is that I wonder how long these rules will remain until it is decided that the .SPORT new gTLD opens to all. The story is always the exact same: at some point, someone notices that there are not enough domains on the market (or that the registry is not lucrative enough) and decides to open to all (for whatever other reason).
Now, when it comes to checking who registers a domain name (see in red above), I don't remember any registry checking all registrants prior to registering domain names so I believe that anyone with a connection to sport in general should be able to register a ".sport" domain name...at some point: not in the beginning of course but later...
Of course, all this is just my opinion and I could (probably not) be wrong ;-)
Not very optimistic, isn't it? (update)
Let's imagine that the .SPORT new gTLD is coming with something new: that kind of innovation that all participants were expecting in the first round of the ICANN new gTLD program? Well, I am not writing more but there's something really innovative coming and according to my understanding of this concept, it could be THAT expected method by all to install domain names on a market.
Of course, all this is just my opinion and I could (probably not) be wrong ;-)
Not very optimistic, isn't it? (update)
Let's imagine that the .SPORT new gTLD is coming with something new: that kind of innovation that all participants were expecting in the first round of the ICANN new gTLD program? Well, I am not writing more but there's something really innovative coming and according to my understanding of this concept, it could be THAT expected method by all to install domain names on a market.
Check the official website here.