different effective charges can differ. Such differences between schemes can naturally explain the smaller IR fixed point values obtained in other computations of the strong coupling, e.g., in Ref. [28] , as qualitatively illustrated on Fig. 3. Q$^{2}$ (GeV$^{2}$) s 0.5 1 1.5 2 2.5 3 10 -1 1 10 Near Conformal  IR Domain Near Conformal Transition Domain IR−UV UV Domain g$_{1}$ V MS 2 2 Q (GeV ) FIG. 3. How different schemes can lead to different values for the IR fixed point. The couplings are computed in the UV region. They freeze in the IR region. The interpolation between UV and IR is drawn freely and is meant to be illustrative, as are the various IR fixed point values. We note that the V and g$_{1}$ schemes are numerically close. Despite the different physics underlying the light-front holographic coupling α AdS s ( Q $^{2}$) and the effective charge α$_{g}$$_{1}$ ( Q $^{2}$) determined empirically from measurements of the Bjorken sum, the shapes of the two running couplings are remarkably close in the infrared regime. The resemblance of α AdS s and α$_{g}$$_{1}$ is understandable if we recall that α AdS s is a natural nonperturbative extension of α$_{V}$ . The scale shift in the CSR between α$_{V}$ and α$_{g}$$_{1}$ is small, making them numerically very close. Furthermore every effective charge satisfies the same pQCD β function to two loops. Thus, the extended α AdS s and α$_{g}$$_{1}$ are also very close at high scales. The AdS and g$_{1}$ couplings share other common features: their β functions have similar structures: zero in the IR, strongly negative in the GeV domain, and zero in the far UV. We can exploit all of these similarities to fix the normalization α AdS s ( Q = 0) = π and 17