  A critical review is presented of the attempts to estimate the Strong
Interactions contributions to the parameter $S$ ($L_{10}$ in the QCD Chiral
Version). In particular it is discussed why the estimations done for
Technicolor are unreliable. $S$ is calculated for heavy doublets of
Techniquarks using the Nonrelativistic Quark Model and keeping $v\simeq 0.25$
TeV fixed. It is found that heavy Techniquarks decouple, so it is possible to
obtain values for $S$ in agreement with present experimental data.
