Let S ad H denote the two events.

Independence means:

p(S and H) = p(S) p(H).

but there is some general athletic ability so the probability that someone

is accepted/selected for H given they have been accepted/selected for S

is greater than for a general person in the population so:

p(S and H) = p(S)p(H|S) > p(S) p(H).

So S and H are not independent

RonL