This is the 17983rd most frequent Russian word.
фехтования
"Фехтование" means "fencing" (the sport of sword fighting).
In this sentence, 'фехтование' refers to the sport of fencing as a physical activity and its benefits.
Фехтование развивает физическую форму и реакцию.
Fencing develops physical fitness and reaction.
Here, 'фехтование' is used to specify the type of competition, indicating the event is related to the sport of fencing.
Соревнования по фехтованию состоятся в субботу.
The fencing competition will take place on Saturday.
In this context, 'фехтованию' (dative case) indicates learning or engaging in the activity of fencing.