Hi Alex,
FES can stimulate the quadriceps during terminal swing to facilitate more normal knee extension in individuals who demonstrate excessive knee flexion in terminal swing.
For AFOs: If the person has increased knee flexion during mid-terminal swing due to a steppage gait pattern stemming from foot drop, an AFO can allow reduced knee flexion during the later parts of swing phase to set the individual up for a more natural initial contact.
This is also a test-taking strategy question. If you know two answers are correct and you can choose an “all of the above” answer, then the third must also be correct.
Chrissy