zyosou wo rensyuusuru.

助走 is read じょそう.

The full sentence is read:

じょそう を れんしゅうする

In normal Japanese writing, it is usually written without spaces:

助走を練習する。

助走 is a noun.

It refers to the approach run / run-up before doing something like a jump, vault, or throw. In this sentence, it is the thing being practiced.

を marks the direct object of the verb.

Here, the verb is 練習する (to practice), and 助走 is what is being practiced, so:

• 助走 = the run-up / approach
• を = object marker
• 練習する = practice

So 助走を練習する means literally something like practice the approach run.

練習 by itself is a noun meaning practice.

To make it into a verb, Japanese often adds する:

• 練習 = practice
• 練習する = to practice

So in this sentence, 練習する is the verbal part.

This is very common in Japanese with suru-verbs:

• 勉強する = to study
• 運動する = to exercise
• 練習する = to practice

Yes, it is understandable and natural enough, especially in a sports context.

However, you may also hear:

• 助走の練習をする

This version feels a little more like do practice of the run-up. Both are possible, but the nuance is slightly different:

• 助走を練習する = practice the run-up itself
• 助走の練習をする = do practice focused on the run-up

In many situations, both would work.

Japanese often leaves out the subject when it is clear from context.

So 助走を練習する。 could mean:

• I practice the run-up
• We practice the run-up
• He/She practices the run-up
• (Someone) will practice the run-up

The subject does not have to be stated unless it is important.

練習する is the plain non-past form.

In Japanese, the non-past can mean:

• a present/habitual action: practice
• a future action: will practice

So depending on context, this could mean:

• (I) practice the run-up
• (I) will practice the run-up

Japanese often relies on context instead of changing the verb form the way English does.

Yes.

• 助走を練習する。 = plain form
• 助走を練習します。 = polite form

Use する in casual speech, dictionary form, notes, or informal writing. Use します when speaking politely.

The spaces are just for learners.

Normally, Japanese is written without spaces:

助走を練習する。

Textbooks and learning materials sometimes add spaces to make the structure easier to see.

Not with the same meaning.

助走をする means to do a run-up / take an approach run.

That describes actually performing the movement.

But 助走を練習する means to practice the run-up, which focuses on training or rehearsal.

So:

• 助走をする = do the run-up
• 助走を練習する = practice the run-up

Mostly, yes.

It is commonly used for physical activities where you take an approach before the main action, such as:

• jumping
• vaulting
• throwing

It can also sometimes be used metaphorically, but in a basic sentence like this, learners should usually understand it as a sports or movement-related term.