Whenever I strum power chords fast I always wind up hitting other strings. Any tips?
practice, and move your hand less. Dont go up and down so far.
I see myself as an intelligent, sensitive human, with the soul of a clown which forces me to blow it at the most important moments.
-Jim Morrison
yeah, pracitise. Begin slow..if playin slow you should strum the right amount of strings, then go for speed, until you get a feel for it
When strumming , your hand should move in a semi-circular way.
Just make the circle smaller, practice and you should be more accurate in no time.
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You shouldn't be them playing fast if you're having trouble, it's going to cause you to mess up. Take it slow and speed it up little by little. Accuracy over speed.
1. Start off slooooooooooooooow

2. Make sure to LIGHTLY touch all the strings you want muted. Practice doing this with one chord over and over until you get it. Lightly touching strings will prevent them from vibrating much and they will only make a faint sound.

Good luck!
'11 Gibson Buckethead LP
'97 Fender Cali Series Strat
?? Samick Bass
'01 Fernandes Dragonfly Elite
Make barre chords, try and strum only the top three strings.

Anything you miss is still part of the chord.
Actually, I go by Dave, but there are already too many Daves on this forum.

Fender MIM Stratocaster
Fender Jaguar Bass
Epiphone EJ200 Super Jumbo
Fender Excelsior 13w
Acoustic B300HD (with matching 1x12 cab)
NYC Big Muff Pi
Just make sure the fingers and thumb of your left hand are touching and muting the strings you're not playing. When I play power chords I usually hit all 6 strings..gives it more 'oomf' if that's what you're going for!
shouldn't all teh strings be muted anyway? other than the ones you have fretted...

that way if you do mess up all you strike is a muted string...not an open string....

like you pointer finger should mute all the other strings you are not fretting....
I haz gotten gud
Use the same motion you use while tremolo picking, DON'T STRUM, small prescise movements, if you STRUM you look like the guys in Scarlett O'Hara: GAY.