מכיוון שההערכה הראשונית הראתה ניידות נמוכה, הוספנו מתיחה.

Here מכיוון means since or because.

In this sentence, מכיוון ש־... introduces the reason:

• מכיוון שההערכה הראשונית הראתה ניידות נמוכה = Since/Because the initial assessment showed low mobility

It is fairly common, but it sounds a bit more formal or written than very everyday כי. In speech, many people would also say:

• כי ההערכה הראשונית הראתה...

So מכיוון ש־ is a good structure to recognize as a more formal way to say because/since.

The ש is the Hebrew linker meaning that or introducing a subordinate clause. After מכיוון, it creates the phrase מכיוון ש־, meaning because/since.

So:

• מכיוון ש־ = because
• ההערכה = the assessment

Together:

• מכיוון שההערכה... = because the assessment...

This is very common in Hebrew: the ש is attached directly to the next word.

Also, because ההערכה already begins with ה־ (the), you get:

• ש + ה + הערכה which looks like שההערכה

That double ה is completely normal.

Because the subject ההערכה (the assessment/evaluation) is a feminine singular noun.

Hebrew past-tense verbs agree with the subject in gender and number.

So:

• הערכה = feminine singular
• therefore the verb is הראתה = showed in feminine singular

Compare:

• ההערכה הראתה = the assessment showed
• הדו"ח הראה = the report showed
  because דו"ח is masculine singular

This is one of the big differences from English: in Hebrew, even past-tense verbs often reflect the gender of the subject.

Because הראשונית is an adjective describing ההערכה, and Hebrew adjectives must agree with the noun in:

• gender
• number
• definiteness

Here:

• הערכה is feminine singular
• it is definite because of ה־: ההערכה = the assessment

So the adjective must also be feminine singular and definite:

• ראשונית = initial (feminine singular)
• הראשונית = the initial

That gives:

• ההערכה הראשונית = the initial assessment

Compare:

• דו"ח ראשוני = an initial report
• הדו"ח הראשוני = the initial report

ניידות means mobility, and נמוכה means low.

So:

• ניידות נמוכה = low mobility

In Hebrew, adjectives usually come after the noun, unlike in English.

So Hebrew says:

• mobility low

not:

• low mobility

Also, ניידות is grammatically feminine singular, so the adjective must match:

• נמוכה = feminine singular form of low

Because הוספנו is the past-tense, first person plural form of the verb להוסיף (to add).

So:

• הוספתי = I added
• הוספת = you added
• הוסיף / הוסיפה = he added / she added
• הוספנו = we added

In this sentence:

• הוספנו מתיחה = we added a stretch / stretching

The ending ־נו is a very common marker for we in past tense.

הוספנו comes from the root י־ס־ף, which has the basic idea of adding or continuing/increasing.

The dictionary form is:

• להוסיף = to add

This verb is in the הפעיל (Hif'il) pattern, which often has forms like:

• הוסיף = he added
• הוסיפה = she added
• הוספנו = we added

A learner will often notice the initial ה־ in many Hif'il verbs. It is one of the clues that the verb belongs to this pattern.

Here מתיחה most likely means a stretch or stretching, especially in a physical, therapeutic, or medical context.

So:

• הוספנו מתיחה = we added stretching or we added a stretch

But מתיחה can have other meanings in different contexts, such as:

• tension
• sometimes even a prank/joke in certain expressions

Context tells you which meaning is intended. Since the sentence talks about an assessment and low mobility, the physical meaning stretching/stretch is the natural one.

Hebrew usually does not have a separate word for a/an.

So:

• מתיחה can mean stretching, a stretch, or just stretch, depending on context.

Hebrew only marks the explicitly with ה־:

• מתיחה = a stretch / stretching
• המתיחה = the stretch / the stretching

This is very normal in Hebrew and often has to be interpreted from context when translating into English.

The comma separates the reason clause from the main clause.

Structure:

• מכיוון שההערכה הראשונית הראתה ניידות נמוכה = reason/background
• הוספנו מתיחה = main action

So the sentence works like:

• Since the initial assessment showed low mobility, we added stretching.

This is similar to English punctuation when a clause like since... comes first.

Yes. Hebrew could also put the main clause first, for example:

• הוספנו מתיחה מכיוון שההערכה הראשונית הראתה ניידות נמוכה.

That means the same thing:

• We added stretching because the initial assessment showed low mobility.

When the because/since clause comes first, the sentence may sound a bit more formal or explanatory. When the main clause comes first, it can feel more straightforward.

Both are natural Hebrew.

Yes, it sounds somewhat formal or professional, especially because of:

• מכיוון ש־ instead of simpler כי
• vocabulary like הערכה ראשונית
• the overall clinical/technical tone

It sounds natural in contexts like:

• medical notes
• therapy reports
• professional documentation
• formal explanation

A more casual version might use simpler wording, but this sentence is perfectly normal in professional Hebrew.