الإحماء مهم قبل جهاز المشي.

Because Arabic often leaves out is/am/are in the present tense.

So الإحماء مهم literally looks like the warm-up important, but it means warming up is important or the warm-up is important.

This is called a nominal sentence:

• الإحماء = the subject
• مهم = the predicate

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

• كان الإحماء مهمًّا = warming up was important

الإحماء means warming up or the warm-up.

It is a verbal noun (often called a maṣdar) related to the idea of making the body warm before exercise. In gym or sports contexts, it is the normal word for warm-up.

So depending on context, it can mean:

• warming up as an activity
• the warm-up as a routine

الـ is the Arabic definite article, like the in English.

In this sentence, الإحماء refers to the activity in a general, known sense: warm-up / warming up as a concept. Arabic often uses الـ in places where English may or may not use the.

Compare:

• الإحماء مهم = warm-up / warming up is important
• إحماء مهم = a warm-up is important

The version with الـ sounds very natural when giving general advice.

Because الإحماء is grammatically masculine, so the adjective/predicate also appears in the masculine form:

• مهم = important (masculine)
• مهمة = important (feminine)

Even though warming up is an activity, the noun إحماء is treated as masculine in grammar.

Because this is an iḍāfa construction, often translated as a noun + of + noun structure.

• جهاز = device/machine
• المشي = walking
• جهاز المشي = walking machine, i.e. treadmill

In an iḍāfa:

• the first noun usually does not take الـ
• the second noun can be definite
• the whole phrase can still be definite

So جهاز المشي is correct, while الجهاز المشي is not the normal structure.

Because in an iḍāfa, the definiteness of the whole phrase depends on the second noun.

Since المشي has الـ, the whole expression جهاز المشي is definite.

So:

• جهازُ مشيٍ = a walking device / a treadmill
• جهازُ المشي = the walking device / the treadmill

This is very different from English, so it is a common point of confusion.

No. Here المشي is a noun, specifically a verbal noun meaning walking.

So in جهاز المشي:

• جهاز = machine/device
• المشي = walking

Together, they make a compound meaning walking machine = treadmill.

It is not saying the machine walks. It is naming the kind of machine.

قبل means before.

In this sentence, it introduces what comes after in time:

• قبل جهاز المشي = before the treadmill / before using the treadmill

Grammatically, the noun after قبل is in the genitive:

• قبلَ جهازِ المشيِ

So if the sentence is fully vocalized, it would be:

• الإحماءُ مهمٌّ قبلَ جهازِ المشيِ.

Yes, literally it is something like before the treadmill, but the intended meaning is before using the treadmill or before going on the treadmill.

Arabic often allows this kind of shortened expression when the context is clear, especially in instructions, fitness advice, or headings.

A more explicit version could be:

• الإحماء مهم قبل استخدام جهاز المشي = Warming up is important before using the treadmill.
• الإحماء مهم قبل المشي على جهاز المشي = Warming up is important before walking on the treadmill.

So the original sentence is understandable, but it is somewhat compressed.

A careful MSA pronunciation would be:

al-iḥmāʾu muhimmun qabla jihāzi l-mashy(i)

A few notes:

• الإحماء = al-iḥ-māʾ
• مهم = muhimm
• قبل = qabla
• جهاز = jihāz
• المشي = al-mashy

With full case endings, it is:

• الإحماءُ مهمٌّ قبلَ جهازِ المشيِ

In normal pause at the end of the sentence, the very last case ending is often not pronounced.