Guitarists of hard rock genres will often use downpicking as much as possible to create a "heavier" sound than the one created with alternate picking, which is a downstroke followed by an upstroke or vice versa.
Downpicking tends to be slower than alternate picking, but is often easier for beginning guitarists to use. Downpicking can also be faster than alternate picking using a technique called sweep picking or 'raking'.
Effective downstrokes picking requires strong wrist and loose guitar belt to make all the movements as tension-free as possible. Picking downstrokes makes the guitar sound tighter, more aggressive and fuller. It also creates the impression that songs played by picking downstrokes are fast even when they're not. Down stroke picking is a common technique in metal and thrash rhythm playing, notably exemplified by Metallica guitarist James Hetfield, Megadeth's Dave Mustaine, and Kerry King of Slayer.
The nature of downstroke picking more than doubles the exertion of the right hand. For long or extended passages, endurance becomes the focus, because as many inexperienced players begin to 'feel the burn', the quality of the music suffers, becoming choppy and disconnected sounding. The popular, easily recognized guitar work of Metallica's "Master of Puppets" is almost entirely played using downstroked eighth notes at a tempo of 216.
A "down(ward) stroke" is a furious, repetitive fast ballistic downstroke. Immediately after strumming all the strings, the pick's trajectory converts to a positive vertical velocity. During the time it is moving upward, the tip of the pick never comes in contact with the strings. This cycle can be repeated however many times is necessary.