From the diagram given in this answer
We see that radial "in" burns shift the perigee towards the burn point, and radial "out" burns shift the apogee towards the burn point.
Thrusting radially outwards (that is, away from the center of the
Earth, or "up") creates an initial vertical motion in the desired
direction, but the chaser then begins falling behind its original
position while the upwards motion slows and stops. A
quarter rev (22 minutes) after the impulse, it is about 900 feet
higher (it would have been 1300 feet higher and still moving, if it
hadn't been for orbital mechanics effects) and about 1700 feet behind
its original position, with all motion in the horizontal direction.
Drifting downwards as well as backwards, and 45 minutes (half a rev)
after maneuver execute, the chaser drops through its original altitude
at a range of about 3500 feet from where it started. It then continues in
this "football" trajectory, dropping but moving forward, then rising and
resuming its original position after a full orbit. The motion then repeats,
subject to outside perturbations.
Thrusting radially inwards (downwards) creates the same-sized "football"
orbit which first pulls ahead and then backwards in its 90-minute cycle.
Source Rendezvous and Proximity Operations Handbook Part 2 pp. 2-13, 2-14 (also contains an earlier version of the diagram)
For completeness, Part 1 of the document is located here.