It's been probably a decade since I saw this film(I didn't see it theatres though), so I'm really fuzzy on the details. Anyways, it was a Russian movie, and it involved a group of teenagers/kids, but it was centered around this one boy in particular. Boxing played a big role in the movie, and all the children only wore one glove when they boxed. The film was ultimately very sad, with the boy's mother dying I believe. I remember that there was a sub-theme of sorts surrounding Sputnik, I believe in the voice over, the boy likened himself to Sputnik. I believe that part happened at while he was at the hospital running to see his mother. All I really remember is that when I saw it, as a child, it felt crushingly depressing.

There is a strong chance that I'm confusing details from multiple movies. If anyone has any idea what this movie is, even if it's just a guess, please let me. I have been searching for a long time now and google is no help.