Just started this easy-as-hell workout to improve my speed picking - whether it be alternate or downstrokes - and IT WORKS! speed picking while playing intricate riffs for long periods can cause strain in the hands and cramping, but if you just simply pick as fast as you can on an open E with palm muting, the burn will occur in your upper arm. this means that you're adjusting your picking to not only use your wrist, but your whole arm to increase the speed of your playing. i've been doing this for a week and i'm finding tempos at 180/190bpm a bit too easy compared to before! the routine for nearly everyday was alternate picking as fast as i could until i felt a nice burn in my arm (NOT my wrist. if you are getting wrist pains, then you need to change your picking technique altogether.), then i'd shake it off and go to downstrokes which would cause a burn lower down my picking arm after a short while. i'd once again shake it off and then would leave my guitar for an hour and then repeat the process at every hour for maybe 5 hours a day. the reason why i leave the guitar for an hour is not only because you can cause serious strain to your arm/wrist, but also because all the muscles are connected your brain, which means if you keep practices consistent and near-perfect, your brain will remember to assert your muscles to the task the same way as one or two hours earlier. guitarists call this 'muscle memory' and definitely comes in handy when you want to learn fast licks and riffs.
you'll definitely be hearing the party vibez guitarists upping the ante on speed soon enough!