Otrowiec's Jewish youth belonged to organizations like: the Zionist Youth, Ha’shomer Ha’tza’ir, Betar, Mizrachi, Ha’shomer Ha’dati, Dror, He’chalutz, left and the "right" Po’alei Tzion, sport clubs of different kinds, Yiddish schools like a Talmud Torah, Yavneh schools of Mizrachi, and many cheders [small religious schools for boys] of various groupings.
Some of these Zionist and other movements were described in the articles, from the 1971 Yizkor book, below:
Movements in Ostrowiec
by Simcha Mintzberg
Movements & Modern School Systems
by Iser Boymfeld
The Revisionist Zionist Movement in Ostrowiec
by I. Birnzweig
Hechalutz Movement in Ostrowiec
Article of Moshe Rosenberg from 1971 Yizkor Book
Background on the history of the worldwide Hechalutz movement can be found here.
Shomer Hatzair
Poalei Zion “Youth” group 1920
קבוצת הנוער פועלי ציון ב1920.
Poalei Zion group 1919
קבוצת פועלי ציון 1919
Hechalutz members of Ostrowiec (Source: page 245 Ostrowiec Yizkor Book of 1971