Burst Dash
From Sonic Retro
The Burst Dash is a move utilised by Sonic the Hedgehog and Blaze the Cat in Sonic Rush and Sonic Rush Adventure. Closely related to the Sonic Boost from Sonic Unleashed the technique is activated by holding the 
or 
button while the ground. Sonic and Blaze can rush forward and plow through enemies while depleting the Tension Gauge.
In both Sonic Rush and Sonic Rush Adventure, you can crouch and roll during the Burst Dash. This is useful when going downhill, as it allows for even greater speeds. Unlike the 3D Sonic Boost, the Burst Dash cannot be activated while in midair, but you can jump up once the Dash is already active.
The super-high-speeds of Burst Dashing are necessary to avoid death in several places during the Rush games, like when pursued by giant boulders as in the picture.