Learn Swedish: Idrottaren masserar sig på vaderna efter loppet. - The athlete massages his calves after the race.

In Swedish, actions performed on one's own body often use a specific reflexive structure: verb + reflexive pronoun (sig) + preposition + definite body part. While masserar sina vader is technically understood, masserar sig på vaderna is the much more natural and idiomatic way to express this in Swedish.

Why is the definite article used in vaderna (the calves) if the English translation uses the possessive 'his'?

Because the reflexive pronoun sig already establishes whose body is receiving the action, Swedish doesn't need to repeat the ownership. Instead of using a possessive pronoun like sina, the body part simply takes the definite form (vaderna).

How do I know to use the preposition på before vaderna?

In these reflexive body structures, the preposition often depends on the physical nature of the body part. På (on) is typically used for exterior surfaces and limbs, such as på benen (on the legs) or på vaderna (on the calves). For more enclosed parts, you would use i (like i magen), and for parts you wrap around, you use om (like om halsen).

Why is the definite form of en idrottare written as idrottaren rather than dropping the 'e'?