"I'm very determined to lead this team strongly from the front. And that starts with performance."
McCullum said his back, which is an ongoing issue involving protruding discs, is "all right".
"It's a little bit stiff but it's a good opportunity to try and lead from the front captaincy-wise as well.
"I'm very determined to put my back aside and try and perform for my team."
Getting a maiden test win as skipper would help not only McCullum but the entire group.
New Zealand's last test win, as the players need no reminding, was the final game under Ross Taylor's leadership, a 167-run victory in Sri Lanka late last year.
That was 10 tests ago. A win would lift the players and help them believe they are on the right track.
"While you always want results, and that's ultimately how you are judged, you have to look at how we've been playing and we've actually played some pretty good cricket over the last little while."
In those nine tests, McCullum has averaged 29.6, compared to his overall average in 79 tests of 34.9
The West Indies may seem a good match for New Zealand - two teams around the middle of the test pecking order. However, McCullum gave them their dues yesterday, while at the same time recognising a good chance to catch them on the hop.
The tourists arrived in dribs and drabs, have had issues over the bowling actions of Shane Shillingford and Marlon Samuels and were soundly thumped in their last two tests in India. Dunedin isn't Mumbai and New Zealand must take the chance in conditions they know against opponents' whose preparation has been haphazard.
And if McCullum and New Zealand walk away with runs and a win by the weekend, the cricket world may look a far different place for the skipper.