Trap bar better than straight bar deadlift?!?

Maybe! Obviously it depends upon your actual goal, but in the first head to head study I've seen the Trap (shrug or parallel grip) deadlift seems to be the better choice. Bear in mind the study was on powerlifters so they have used predominantly a straight bar, so to have a higher max on a trap bar is something to note (although it depends on the exact design of the bar - some trap bars have a higher handle that raises the lift off point, so it would be like lifting a straight bar off of blocks - I'd have to see the full study before I could decide).

Quote :

http://www.ncbi.nlm.nih.gov/pubmed/21659894

J Strength Cond Res. 2011 Jul;25(7):2000-2009.
A Biomechanical Analysis of Straight and Hexagonal Barbell Deadlifts Using Submaximal Loads.
Swinton PA, Stewart A, Agouris I, Keogh JW, Lloyd R.
Source

1School of Health Sciences, Robert Gordon University, Aberdeen, United Kingdom; 2Center for Obesity Research and Epidemiology, Robert Gordon University, Aberdeen, United Kingdom; 3Institute of Sport and Recreation Research New Zealand, School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand; and 4School of Social and Health Sciences, University of Abertay, Dundee, United Kingdom.
Abstract

Swinton, PA, Stewart, A, Agouris, I, Keogh, JWL, and Lloyd, R. A biomechanical analysis of straight and hexagonal barbell deadlifts using submaximal loads. J Strength Cond Res 25(7): 2000-2009, 2011-The purpose of the investigation was to compare the kinematics and kinetics of the deadlift performed with 2 distinct barbells across a range of submaximal loads. Nineteen male powerlifters performed the deadlift with a conventional straight barbell and a hexagonal barbell that allowed the lifter to stand within its frame. Subjects performed trials at maximum speed with loads of 10, 20, 30, 40, 50, 60, 70, and 80% of their predetermined 1-repetition maximum (1RM). Inverse dynamics and spatial tracking of the external resistance were used to quantify kinematic and kinetic variables. Subjects were able to lift a heavier 1RM load in the hexagonal barbell deadlift (HBD) than the straight barbell deadlift (SBD) (265 ± 41 kg vs. 245 ± 39 kg, p < 0.05). The design of the hexagonal barbell significantly altered the resistance moment at the joints analyzed (p < 0.05), resulting in lower peak moments at the lumbar spine, hip, and ankle (p < 0.05) and an increased peak moment at the knee (p < 0.05). Maximum peak power values of 4,388 ± 713 and 4,872 ± 636 W were obtained for the SBD and HBD, respectively (p < 0.05). Across the submaximal loads, significantly greater peak force, peak velocity and peak power values were produced during the HBD compared to during the SBD (p < 0.05). The results demonstrate that the choice of barbell used to perform the deadlift has a significant effect on a range of kinematic and kinetic variables. The enhanced mechanical stimulus obtained with the hexagonal barbell suggests that in general the HBD is a more effective exercise than the SBD.