It's funny, I asked him about this when he did a signing session/clinic at my local music store last year. I remembered watching him double thumb "What Is Hip"... http://www.youtube.com/watch?v=k0XbH_qMXso
...and to me the stuff he's doing there is just insane, considering the fact that he's doing it with 045-105 gauge strings and he's really slamming!
, which is also why I like him the best when it comes to slapping in general, and also double thumbing specifically; the great TONE he has. Other players may be quicker and slicker with their light gauge strings and (let's say) Fodera basses
but I feel that it comes at a cost: it's more two dimensional as opposed to Marcus' 3D Fender tone.
So I asked him if he, for instance, could play "What Is Hip" like that three times in a row; no problem, or does he feel the burn?
And he said that he definitely felt i;, HARD!
Which is why, he said; he has to switch to fingerstyle in the middle of it (about 4 min into it in the clip) because he feels as if his arm is about to fall off!
So it's not like he's some kind off super human bass slapping machine, he's just very, very strong. He also said that for him the front pick up cover is quite important to him; for positioning the right hand and that a lot of energy actually goes into that cover, he hits it. But he has to have it there, because if it's not, it messes up his technique. And this was demonstrated when he played a Jazz Bass without the cover. He got tired much more quickly and his groove/feel also suffered slightly. He was still able to do it, but it wasn't Marcus being Marcus, you know?
Anyway, what a great player and a great guy too! Very approachable, intensely listening and very kind. Especially with the young kids that has just started to play. I remember watching him interact with them and thinking that he's the kind of guy that is able to inspire a kid to play; probably for the rest of his/her life.