The ornamental design for adjustable leg support, as shown and described.
FIG. 1 is a front view of the adjustable leg support with support in the up position showing my new design;
FIG. 2 is a rear view thereof;
FIG. 3 is a side view thereof;
FIG. 4 is a is a front view of the adjustable leg support with support in the down position;
FIG. 5 is a rear view thereof;
FIG. 6 is a side view thereof; and,
FIG. 7 is a side view of the adjustable leg support shown greatly reduced in a condition of use.
The broken line showing of human form and treatment table is included for the purpose of illustrating a portion of the adjustable leg support that forms no part of the claimed design.