This article is from the Big Folks Sports and Activities FAQ, by email@example.com (Sharon Curtis) with numerous contributions by others.
People of all shapes, sizes and ages can play tennis. Emphasis
is mostly on hand-eye coordination and some arm strength, though
being able to move about the court and having some power help a
great deal as well!
Specifically relevant to fat people are the following points.
You may find that you have a preference as to which surface you
play on. Common surfaces in use are grass, artificial grass,
cement, clay, shale.
Some people find that being heavy makes them slip and slide less
on shale (clay with a scattering of very fine red gritty stuff on
the top). Also, if you're turning to go for a shot, as the shale is
loose, it turns with you, whereas surfaces like artifical grass
which provide more friction also provide more resistance to you as
you turn, thus helping you to pull a tendon or similar.
Then again, if you're a player that falls over frequently, you
might just want a surface with a nice soft landing.
If your thighs rub together and you're wearing very short shorts
or a tennis skirt or dress, you might get friction rubs on your
inner thighs. One way to avoid this is by wearing cycling shorts
or leggings or longer shorts.
Clothing can be whatever you usually wear as exercise wear, but
if you're trying to get hold of smart tennis whites with a
matching t-shirt/sports-shirt and skirt/shorts, then unfortunately
those seem to be very scarce for anyone over average size.
If you're playing in a tennis match that goes on for several sets, or
you're playing in some other long session that it's not easy to get
a drink in the middle of, then take a water bottle with you and use
it frequently to keep hydrated, particularly if it's a hot day.