Does substituentʹs conformation influence the kinetics of reduction reactions on trans-4-X-decal-1-ones and to what extent?

Stereochemistry and relative rates kax and keq of reduction reactions on title compounds have been measured under five different reaction conditions (NaBH4 in i-PrOH, LiBH4 and NaAlH4 in THF and LiAlH4 in THF and in Et2O). Experiments indicate that axial substituents behave as far less electronegative than their equatorial counterpart in reactions at the equatorial side of molecules.