I like explaining programming skills and mathematical theories to others because in the teaching or writing process I can learn more than I study alone. Some theories in education psychology also prove that this method works very well, and we can see that on the Wikipedia page, but most articles only mention two out of the three domains of learning proposed by Bloom like the following (quoted from the Wikipedia page):
respect for other people, planning, problem solving, taking chances in public, and communication skills
The above skills are only cognitive and affective learning but not psychomotor.
Can we improve ourselves better in sports (like tennis) by teaching others (mostly who play worse then ourselves)?