Learn Hardcore Korean: sae undongbogeul ipgo gongwone ganeun ge johayo. - I like going to the park wearing new workout clothes.

입다 means “to wear.” When you add -고, it becomes 입고, the connective form, which links actions. So 입고 literally means “wearing (and then)…,” connecting it to the next action, 공원에 가다.

Why is 새 used before 운동복, and what role does the -을 in 운동복을 play?

새 is an attributive adjective meaning “new,” and it directly modifies the noun 운동복 (“workout clothes”).
The particle -을 is the object marker. It shows that 운동복 is the direct object of 입고 (you wear the workout clothes).

What does 공원에 mean, and why is the location marked with -에 instead of -에서?

공원 means “park.”
-에 indicates the destination (“to the park”).
If you used -에서, it would mean “at the park” (location of an action), not “going to the park.”

What is the function of 가는 게, and why not just 가는 것이?

가는 is the present participle of 가다 (“to go”).
것이 nominalizes the verb (“the act of going”). In everyday Korean, 것이 contracts to 게.
So 가는 게 = “going” as a noun phrase.

Why is 것이 contracted to 게, and is this contraction always possible?

In spoken and written Korean, 것이 often contracts to 게 after adjectives or verbs ending in -는 or -은.
It’s very common and natural: 먹는 것이 → 먹는 게, 좋은 것이 → 좋은 게.
In very formal or written styles, you might see the full 것이, but 게 is fine in most contexts.

What nuance does 좋아요 carry, and what tense and politeness level is it?

좋아요 is the polite present tense form of 좋다 (“to be good/like”).
It can express:
• A general preference (“I like doing X.”)
• A recommendation or mild advice (“It’s good to do X.”)
The ending -아요/어요 makes it polite but not overly formal.

Why is the subject omitted in 새 운동복을 입고 공원에 가는 게 좋아요? Who is implied?

Korean often drops the subject when it’s clear or unimportant. Here, the speaker (or a general “we/you”) is implied. It’s understood as: “(I/we/you) like going to the park wearing new workout clothes.”

Is this sentence stating a personal preference, giving advice, or both?

It does both:

As a personal preference, it means “I/We like going to the park in new workout clothes.”
As a recommendation, it can imply “It’s a good idea to go to the park in new workout clothes.” The context will tell you which shade of meaning is intended.