Helicity quark distributions from DIS and SIDIS measured in COMPASS

An overview of recent COMPASS (NA58/SPS) results on the determination of longitudinal polarized quark distributions is given. The results were obtained in inclusive and semi-inclusive deep-inelastic scattering of a 160 GeV polarized muon beam off a large polarized $^{6}$LiD target. The covered kinematic range is 0.004 $< x <$ 0.7 and 1 $< Q^{2} <$ 100 (GeV$/c$)$^{2}$. The presented data were collected by COMPASS in the years 2002$-$2004.