also: トレーニングウエア
noun
training wear; sportswear; activewear; tracksuit
General term for clothing worn during exercise or sports. Can refer to a matching jacket and pants set (tracksuit) or any athletic clothing.
ジムに行くときは、いつもトレーニングウェアに着替えます。
I always change into my training wear when I go to the gym.
新しいトレーニングウェアを買ったので、運動が楽しみです。
I bought new sportswear, so I'm looking forward to exercising.
スポーツウェア is a broader term for sports clothing in general, while トレーニングウェア specifically implies clothing for training or working out.
ジャージ often refers to a tracksuit or jersey material, and can be used more casually. トレーニングウェア is a more formal or specific term for athletic training clothes.
Wasei-eigo (Japanese-made English) from 'training' + 'wear'. Not a direct loanword from English.