A composite structural member is provided. The structural member includes a tubular shaft having a mating region of stiffness, and possibly thickness, greater than another region of said shaft. The shaft defines a lumen, and a fitting is disposed in the lumen. The fitting has a coupling region that defines at least one recessed portion bounded by one or more non-recessed portions, and the mating region mates with the coupling region of said fitting. As such, the shaft and fitting are mechanically restrained from at least some relative movement due to interference of the shaft and the fitting. A sleeve may be coupled to said shaft, for example, by including a tubular inner surface that proximately surrounds at least part of said shaft and mating region, for discouraging expansion of the mating region of said shaft.