Betis dan paha saya pegal setelah naik tangga berkali-kali.

In Indonesian, possession often comes after the noun:

• betis saya = my calf/calves
• paha saya = my thigh/thighs

So betis dan paha saya means my calves and thighs.

This is normal Indonesian word order. Unlike English, you do not usually put a possessive word before the noun the way you do in my calves.

It usually means the body parts in a general sense: my calves and thighs.

Indonesian often does not mark singular/plural unless it is important. So:

• betis can mean calf or calves
• paha can mean thigh or thighs

Context tells you what is meant. In this sentence, English would most naturally interpret it as my calves and thighs.

Betis means calf, the lower back part of the leg below the knee.

This is more specific than kaki, which can mean leg, foot, or sometimes the whole lower limb depending on context.

So:

• betis = calf
• paha = thigh
• kaki = leg/foot

Not exactly.

Pegal usually means something like:

• achy
• sore
• stiff from exertion
• tired and uncomfortable in the muscles

It is very commonly used for the feeling you get after exercise, walking a lot, climbing stairs, carrying something heavy, and so on.

By contrast, sakit is broader and often stronger:

• sakit = painful, hurting, ill
• pegal = achy/sore/stiff, especially in muscles

So pegal is a very natural choice here because the discomfort comes from repeated physical effort.

Indonesian often does not use a verb equivalent to to be in simple descriptive sentences.

So:

• Betis dan paha saya pegal
  literally: My calves and thighs sore/achy

This is a complete and natural sentence in Indonesian.

You only need a copula like adalah in more limited situations, and it would sound wrong here. So pegal directly functions as the predicate.

Because Indonesian often omits the subject in time clauses when it is already obvious from context.

So:

• setelah naik tangga = after climbing stairs
• setelah saya naik tangga = after I climbed stairs

Both are possible, but the version without saya is more compact and very natural when the subject is clearly the same person as in the main clause.

Because naik by itself is already a very common verb meaning to go up, to climb, or to get on/up depending on context.

In naik tangga, it means climb/go up the stairs.

Compare:

• naik tangga = go up/climb the stairs
• menaiki tangga = climb the stairs
  This is also possible, but a bit more formal or less casual in feel.
• menaikkan usually means to raise something or to increase something, so it does not fit here.

So naik tangga is simple and idiomatic.

Because reduplication is not needed here.

Tangga already works naturally to mean stairs/staircase in context. Indonesian does not always need plural marking the way English does.

So:

• naik tangga = climb stairs / go up the stairs

If you said tangga-tangga, it would usually suggest multiple staircases in some context, which is probably not what this sentence means.

Berkali-kali means repeatedly, many times, or over and over.

It comes from kali, which can mean time/occurrence in counting actions:

• sekali = once
• dua kali = twice / two times
• tiga kali = three times

The form berkali-kali is an idiomatic expression meaning many times repeatedly.

So:

• naik tangga berkali-kali = climbing the stairs many times / repeatedly going up the stairs

Because it modifies the action naik tangga.

The structure is:

• Betis dan paha saya pegal = main statement
• setelah naik tangga berkali-kali = time phrase explaining the cause/background

Placing berkali-kali after naik tangga is natural because it tells you how often that action happened.

Yes. That is also natural.

• Betis dan paha saya pegal = My calves and thighs are sore.
• Betis dan paha saya terasa pegal = My calves and thighs feel sore.

Adding terasa makes it slightly more explicit that this is how they feel. Without terasa, the sentence is still completely natural and common.

It is mostly neutral everyday Indonesian.

The words are natural in normal conversation:

• betis
• paha
• pegal
• naik tangga
• berkali-kali

It does not sound especially formal, but it is not slangy either. It would work well in daily speech.

Yes, if you want to be less specific.

• Betis dan paha saya pegal = specifically my calves and thighs are sore
• Kaki saya pegal = my legs are sore or sometimes more generally my lower limbs feel sore

Using betis dan paha is more precise. Using kaki is broader and more general.

It can be rearranged a little.

The original order is very natural:

• Betis dan paha saya pegal setelah naik tangga berkali-kali.

You could also say:

• Setelah naik tangga berkali-kali, betis dan paha saya pegal.

This puts the after... phrase first for emphasis. Both are correct. The meaning stays the same.