Setelah senam, kami meregangkan paha dan betis supaya tidak terlalu pegal besok pagi.

Setelah means after. Indonesian often puts a time phrase at the beginning of the sentence to set the scene first.

So:

• Setelah senam = After exercise / After the workout
• kami meregangkan paha dan betis ... = we stretched our thighs and calves ...

This fronted time phrase is very natural in Indonesian. You could also say:

• Kami meregangkan paha dan betis setelah senam.

That would also be correct, just with a slightly different flow.

Senam usually refers to exercise, workout movements, or gymnastics/aerobics-type exercise, depending on context.

In this sentence, it most naturally means something like:

• exercise
• a workout
• doing exercise movements

It does not necessarily mean formal Olympic gymnastics. In everyday Indonesian, senam can be quite broad.

This is a very common learner question.

Indonesian has two words for we:

• kami = we, but not including the listener
• kita = we, including the listener

So kami meregangkan... means the speaker is talking about their group, but the person being spoken to is not part of that group.

If the listener had also done the stretching, kita might be used instead.

Meregangkan means to stretch something.

It comes from the root regang, which is related to being stretched or taut. The affixes change it into a verb:

• meN- ... -kan often makes a transitive verb
• so meregangkan paha dan betis = to stretch the thighs and calves

Compare:

• regang = stretch/tautness as a root idea
• meregangkan = to stretch something
• peregangan = stretching, the act of stretching

So in this sentence, meregangkan is used because the object is stated: paha dan betis.

Because Indonesian often leaves possession unstated when it is obvious from context.

So:

• kami meregangkan paha dan betis literally looks like
• we stretched thighs and calves

But naturally it means:

• we stretched our thighs and calves

This is very common with body parts in Indonesian. You do not always need kami punya, paha kami, or betis kami unless you want to emphasize ownership or make things extra clear.

These are body-part words:

• paha = thigh
• betis = calf (the lower back part of the leg)

So paha dan betis means thighs and calves.

A learner might confuse betis with the whole lower leg, but it usually refers specifically to the calf area.

Supaya means so that, in order that, or so.

It introduces a purpose or intended result:

• supaya tidak terlalu pegal besok pagi = so that we/they won’t be too sore tomorrow morning

Other similar words are:

• agar = also so that, a bit more formal
• biar = can also mean so that / let, often more informal in speech

So here, supaya is a very natural choice for expressing purpose.

Because Indonesian often omits subjects when they are understood from context.

In this sentence, the understood subject is something like:

• we or
• our legs/muscles

So the meaning is:

• so that we wouldn’t be too sore tomorrow morning or more specifically
• so that our thighs and calves wouldn’t be too sore tomorrow morning

Indonesian does this a lot. If the meaning is obvious, the language often sounds more natural without repeating the subject.

Pegal means sore, achy, or stiff from physical exertion.

It is not exactly the same as capek.

• pegal = physical soreness/aching in the body or muscles
• capek = tired/fatigued

So after exercise:

• Saya capek = I’m tired
• Kaki saya pegal = My legs are sore/achy

In this sentence, pegal is the right word because stretching is meant to reduce muscle soreness, not just general tiredness.

It means not too sore or not overly achy.

Breakdown:

• tidak = not
• terlalu = too, excessively
• pegal = sore/achy

So:

• tidak terlalu pegal = not too sore

This sounds natural because it does not suggest avoiding all soreness completely, just reducing it.

Besok pagi means tomorrow morning.

Putting it at the end is natural because it gives the time of the expected result:

• supaya tidak terlalu pegal besok pagi = so as not to be too sore tomorrow morning

Indonesian time expressions are fairly flexible. You could also hear:

• supaya besok pagi tidak terlalu pegal

That is also correct. The original sentence sounds natural and flows well.

The comma is helpful, especially in writing, because Setelah senam is an introductory time phrase.

So:

• Setelah senam, kami meregangkan paha dan betis ...

This is good standard punctuation.

In very casual writing, people may omit the comma, but using it here is clearer and more polished.

Yes. Agar would work very well here.

For example:

• Setelah senam, kami meregangkan paha dan betis agar tidak terlalu pegal besok pagi.

That means the same thing.

The difference is mostly style:

• supaya = very common and natural
• agar = slightly more formal or written in tone

Both are correct.

Yes, and that is actually the most natural interpretation.

Even though the second clause does not repeat the subject, the context strongly suggests:

• we stretched our thighs and calves so that they wouldn’t be too sore tomorrow morning

In English, we often make that explicit with our thighs and calves or our legs. In Indonesian, leaving it implicit is completely normal.

Because meregangkan directly describes the action of stretching the body parts.

Compare:

• kami meregangkan paha dan betis = we stretched our thighs and calves
• kami melakukan peregangan = we did stretching

Both are possible, but they are structured differently:

• meregangkan focuses on the action done to specific body parts
• melakukan peregangan focuses on the activity of stretching in general

The original sentence is more specific because it names paha dan betis.