There is a big turnaround of the national team members.
There are lot's of members coming and going.
Turnaround means there is always new staff leaving and being employed. We normally use this phrase when there is a type of job where many people don't like to stay in long term employment. These jobs would be difficult/demanding or intense sports.
Coming and going is the same as turnaround, it just implies that new members are always being recruited.
"Turnaround"とは従業員の入れ替わりが激しい事をいいます。
普通、ある職種で従業員がすぐやめてしまう様な時に、このフレーズを使います。
これらは難しい仕事か要求の多い仕事、又は激しいスポーツでしょう。
"Coming and going"とは"turnaround"と同じ意味で、いつも求人を出している、入れ替わりが激しいという事を意味します。
Formation of a national soccer team is an ongoing process of young replacing old
As it evolves, the national team has a continual influx of younger players
As in all things, players age and as they near the end of their career - be it at national or local level - they will find themselves replaced by 'up and coming' younger players. It is impossible to maintain an incredible level of fitness andretain the same sharpness of skills as we age. The balance of experience with youth is an ongoing problem for any football coach. Some players may defy the ageing process briefly, but what is inevitable will always be inevitable.
全ての事がそうであるように、選手の年齢と共に選手生命の終わりが近づいていきます。
それが、国の代表だろうが、地方レベルの事でも。
彼らは 'up and coming' （活気にみちあふれている）若い選手と交代します。
年齢と共に信じられないほどの体の体調を保ったり、同じ鋭いスキルを維持し続けつ事は可能です。
若さと経験のバランスは多くのサッカーチーム監督にとって進行中の問題です。
何人かの選手はこのエイジングの問題にちょっとの間は立ち向かうことが出来ますが"what is inevitable will always be inevitable"（避けられない事は必ず避けることはできません）
There is always new team member playing for the national soccer team.
There is a big turnover of players for the Nation soccer team.
"There is always a new team member playing for the national soccer team." This explains to the person that often there are new and different players in the team.
"There is a big turnover of players for the Nation soccer team." This explains to the person that the soccer team members are always changing.
"There is always a new team member playing for the national soccer team."
（サッカー代表は、いつも新しい選手がプレーしている）
これはいつも新しい違う選手がチームでプレーして言事を説明しています。
"There is a big turnover of players for the Nation soccer team."
（サッカー代表チームの選手は転換が激しい）
これはサッカーチームの選手はいつも変わっている、という説明になります。
The National team is constantly evolving, using new blood to replace older players
When there is "a state of flux" or there is endless change...We might say things are constantly evolving...And in this case repalcing older with younger players:-)
"The National team is constantly evolving, using new blood to replace older players"
"a state of flux"(変動期)とは終わりがなく変わり続けていることです。継続的に進化しているとも言えるかもしれません。
この場合は年齢の高い選手を若い選手に変えているころです。
"The National team is constantly evolving, using new blood to replace older players"
国の代表チームは昔からの選手を新しい選手に代えながら進化し続けている
There is a big turnover of players/members of the national team
The members/players of the national football team change constantly
When talking about a football (soccer) team players usually change all the time as younger or more talented players come into the team this is called 'turnover' or 'turnaround' or you can say to 'change constantly'
There is a big turnover of players in the national soccer team
There are a lot of young, new players in the national soccer team.
The members of the national soccer team change constantly!
There are many ways to say this depending on what detail you would like to give. Saying there is a 'big turnover' of players explains that there are frequent changes, but does not specify what the changes are. It is quite a natural phrase to use.
The second example gives more of an explanation. You could also extend this sentence by linking it with the first e.g. 'there is a big turnover of players in the national soccer team. We have had a lot of young, new players recently.'
The final sentence also shows that the team is changing but does not give specific details. Again, you could add these in if you want to.
これは何を伝えたいかによっていろいろな言い方ができます。
'There is a big turnover of players' は選手が頻繁に入れ替われるという意味ですが、 それがどのような変化なのかは明示していません。すごく自然なフレーズです。
二つ目の例はより具体的です。
これを一つ目の文と結合することもできます。例えば：
'There is a big turnover of players in the national soccer team. We have had a lot of young, new players recently.'
（サッカーの代表チームは選手の入れ替わりが激しいです。若くて新しい選手が最近たくさん入りました）
三つ目の文もチームが変化していることを表しますが、具体的なことは伝えていません。上の例同様この場合も、具体的な情報を加えてもいいです。
They keep swapping players to keep fresh blood on the national team
I would use the word 'always' to emphasise that this is a very common occurrence. The phrase 'swapping players' simply means 'trading players' or 'changing players'. 'Fresh blood' is a phrase that we use in England which means 'young' or 'not tired'. It is also essential that you say 'the national team' to show who you are talking about unless it is already obvious from the previous conversation.
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