  The phenomena of strong running coupling and hadron mass generating have been
studied in the framework of a QCD-inspired relativistic model of quark-gluon
interaction with infrared confined propagators. We derived a meson mass
equation and revealed a specific new behaviour of the mass-dependent strong
coupling $\hat\alpha_s(M)$ defined in the time-like region. A new infrared
freezing point $\hat\alpha_s(0)=1.03198$ at origin has been found and it did
not depend on the confinement scale $\Lambda>0$. Independent and new estimates
on the scalar glueball mass, 'radius' and gluon condensate value have been
performed. The spectrum of conventional mesons have been calculated by
introducing a minimal set of parameters: the masses of constituent quarks and
$\Lambda$. The obtained values are in good agreement with the latest
experimental data with relative errors less than 1.8 percent. Accurate
estimates of the leptonic decay constants of pseudoscalar and vector mesons
have been performed.
