The ornamental design for a swimming brace support, as shown and described.
FIG. 1 is a side perspective view of the swimming brace support showing my design, an opposite side view being a mirror image thereof.
FIG. 2 is a top plan view thereof;
FIG. 3 is a front elevation view thereof;
FIG. 4 is a back elevation view thereof;
FIG. 5 is another side perspective view thereof, showing environmental effects in broken lines; and,
FIG. 6 is a top perspective view thereof.
The environment effects include the swimming pool and water, presented in broken line format. The portions in broken lines are presented for illustrative purposes only and form no part of the claimed design.