التوازن مهم على جهاز التجديف.

There is no separate word for is in the present tense in Arabic.

So التوازن مهم literally looks like the balance important, but it means Balance is important.

This is a very common Arabic sentence pattern called a nominal sentence:

• التوازن = the subject
• مهم = the predicate / description

If you wanted a past or future meaning, then Arabic would use a verb:

• كان التوازن مهمًّا = Balance was important
• سيكون التوازن مهمًّا = Balance will be important

In Arabic, abstract nouns are often made definite with الـ when talking about the concept in a general sense.

So:

• التوازن = balance / the concept of balance

This is natural in Arabic, even when English would not use the.

Compare:

• الصبر مهم = Patience is important
• النوم ضروري = Sleep is necessary
• التوازن مهم = Balance is important

So the الـ here does not necessarily mean a very specific balance; it can simply refer to the idea of balance in general.

Because it agrees with التوازن, which is a singular masculine noun.

In Arabic, adjectives and predicate adjectives usually agree with the noun in:

• gender
• number
• definiteness (in many adjective uses)

Here:

• التوازن is singular masculine
• so the predicate is مهم

If the noun were feminine, you would usually use مهمة:

• الرياضة مهمة = Exercise is important

Because مهم here is not an attributive adjective directly attached to a noun like the important balance. It is the predicate of the sentence: Balance is important.

So:

• التوازن المهم = the important balance
  (noun + adjective phrase)
• التوازن مهم = balance is important
  (full sentence)

That is why مهم is indefinite here.

على usually means on, upon, or sometimes while using / on the subject of, depending on context.

In this sentence, على جهاز التجديف means:

• on the rowing machine

This is natural because in English and Arabic alike, we often say on with equipment you use physically:

• على الدراجة = on the bicycle
• على الجهاز = on the machine

So على is the normal preposition here.

Because this is an إضافة structure, often called a genitive construct or noun-noun construction.

جهاز التجديف literally means:

• machine of rowing

This is how Arabic commonly expresses compounds like:

• كتاب الطالب = the student’s book
• باب البيت = the door of the house
• جهاز التجديف = rowing machine

In an إضافة:

1. the first noun does not take الـ
2. the second noun determines whether the whole phrase is definite or indefinite

So:

• جهاز التجديف = the rowing machine / rowing machine, depending on context
• because التجديف is definite, the whole phrase is definite

التجديف is a verbal noun (often called a maṣdar) meaning rowing.

So:

• جدّف = he rowed
• التجديف = rowing

In جهاز التجديف, Arabic uses the maṣdar to name the function of the machine:

• جهاز التجديف = rowing machine
• literally: machine of rowing

This is a very common Arabic pattern:

• غرفة النوم = bedroom, literally room of sleeping
• حذاء الرياضة = sports shoe, literally shoe of sport
• آلة التصوير = camera, literally machine of photographing

A fully vowelled version would be:

التَّوَازُنُ مُهِمٌّ عَلَى جِهَازِ التَّجْدِيفِ

The endings are:

• التوازنُ → nominative, because it is the subject
• مهمٌّ → nominative, because it is the predicate
• على → preposition
• جهازِ → genitive, because it follows على
• التجديفِ → genitive, because it is the second part of an إضافة

In normal everyday writing, these short vowels are usually omitted.

Yes, literally that is very close. But in natural English, you would usually say:

• Balance is important on the rowing machine

The Arabic is using التوازن in a general sense, not necessarily referring to one specific balance already mentioned.

So the literal structure may look more definite than the natural English meaning.

That would sound less natural for the meaning on the rowing machine.

• على جهاز التجديف = on the rowing machine
• في جهاز التجديف would mean something more like in the rowing machine, which does not fit the intended idea very well

So for talking about using the machine, على is the better choice.

Yes, Arabic word order is flexible, but the given order is very natural.

Standard order here:

• التوازن مهم على جهاز التجديف

You might also hear or see:

• على جهاز التجديف، التوازن مهم

This gives extra emphasis to on the rowing machine.

But for a learner, the original version is the most straightforward and standard.

It is a very clear and correct Modern Standard Arabic expression.

You may also encounter other wording depending on region or context, but جهاز التجديف is a good standard MSA phrase and is easy to understand.

Arabic often forms equipment names this way:

• جهاز + activity
• آلة + activity

So جهاز التجديف is a normal and useful pattern to learn.

مهم is pronounced roughly muhimm.

The reason it sounds like a doubled m is that the middle consonant is doubled in the fully vowelled form:

• مُهِمّ

That final ّ is a shadda, which means the consonant is doubled.

So it is not just muhim but muhimm.

It is clearly Modern Standard Arabic and sounds natural in an instructional, educational, or written context.

For example, you might see it:

• in exercise instructions
• in a textbook
• in a fitness article
• in subtitles or formal speech

In everyday spoken dialects, people might phrase it differently, but as MSA this sentence is perfectly normal.