Nach dem Sport nehme ich eine kurze Dusche und benutze mein neues Duschgel.

Because nach takes the dative case here, and Sport is masculine: der Sport.

So the forms are:

• nominative: der Sport
• accusative: den Sport
• dative: dem Sport

That is why you get nach dem Sport.

A useful rule: when nach means after in a time sense, it is followed by the dative.

• nach dem Essen = after the meal / after eating
• nach der Arbeit = after work
• nach dem Sport = after sports / after exercising

German main clauses follow the verb-second rule. The conjugated verb must be in the second position.

Here, the sentence begins with the time phrase Nach dem Sport, so that takes the first position. The verb must then come next:

• Nach dem Sport = position 1
• nehme = position 2
• ich = after the verb

So:

• Nach dem Sport nehme ich ...

If you start with ich, then the verb still stays second:

• Ich nehme nach dem Sport eine kurze Dusche ...

Both are grammatical, but the original sentence puts emphasis on when this happens.

Because that is a normal German expression. Eine Dusche nehmen means to take a shower, just like English.

Other common ways to say this are:

• duschen = to shower
• eine Dusche nehmen = to take a shower

So these are both natural:

• Nach dem Sport nehme ich eine kurze Dusche.
• Nach dem Sport dusche ich kurz.

The version with eine kurze Dusche nehmen sounds slightly more like a fixed expression, while dusche ich kurz is a bit more direct and simple.

This is about adjective endings.

The noun is die Dusche, which is feminine. In this sentence it is the direct object of nehme, so it is in the accusative:

• nominative: eine kurze Dusche
• accusative: eine kurze Dusche

For feminine nouns, eine stays eine in both nominative and accusative, and the adjective takes -e here:

• eine kurze Dusche
• eine kalte Dusche
• eine schnelle Dusche

So kurze is the correct adjective form for a feminine singular noun after eine.

Because Duschgel is neuter: das Duschgel.

In the sentence, it is the direct object of benutze, so it is in the accusative. For neuter singular, the possessive determiner mein stays mein, and the adjective takes -es:

• nominative: mein neues Duschgel
• accusative: mein neues Duschgel

Compare:

• masculine: meinen neuen Ball
• feminine: meine neue Tasche
• neuter: mein neues Duschgel

So the form is correct because Duschgel is neuter.

Duschgel means shower gel or body wash. It is specifically the product you use in the shower.

It is not exactly the same as Seife:

• die Seife = soap
• das Duschgel = shower gel / body wash

So if someone says mein neues Duschgel, they mean a new shower product, not necessarily a bar of soap.

Yes, absolutely. That sounds very natural.

Your original sentence:

• Nach dem Sport nehme ich eine kurze Dusche und benutze mein neues Duschgel.

Alternative:

• Nach dem Sport dusche ich kurz und benutze mein neues Duschgel.

The difference is mostly style:

• eine kurze Dusche nehmen = a fixed expression, a little fuller
• kurz duschen = shorter and often more everyday

Both are correct.

Because German can join two verbs with und when they share the same subject.

So:

• Nach dem Sport nehme ich eine kurze Dusche und benutze mein neues Duschgel.

means:

• Nach dem Sport nehme ich eine kurze Dusche und ich benutze mein neues Duschgel.

The second ich is simply omitted because it is understood.

Both are possible, but leaving it out is more natural here.

Because in German, all nouns are capitalized.

Here the nouns are:

• der Sport
• die Dusche
• das Duschgel

So they must be written with capital letters.

This is one of the most noticeable spelling rules in German, and it helps you identify nouns quickly.

In everyday German, nach dem Sport often means after doing sports / after working out / after exercise in a general sense.

It does not have to refer to one specific sport match or event. It can simply mean the time after physical activity.

So a learner can usually understand it as:

• after sports
• after exercise
• after working out

The exact English wording depends on context.

Both are possible, but benutzen is the more everyday choice here.

• benutzen = to use
• verwenden = to use, often a little more formal or neutral

With personal-care items like Duschgel, benutzen sounds very natural:

• Ich benutze mein neues Duschgel.

You could also say:

• Ich verwende mein neues Duschgel.

That is correct too, but many speakers would choose benutzen in casual conversation.

It can mean either, depending on context.

• brand-new product you just bought
• a product that is new for you, even if not literally just manufactured

German neu works much like English new in that respect. The sentence itself does not force one interpretation, so context decides.