Just one random thing, but apparently not? Actually it say it affect 'linear movements' but I don't know what that means.
Also, there are different kinds of marijuana which have different affects, as well as different physiologies. I know a guy who literally become paralyzed for several hours if he smokes marijuana.
In my own personal experience, I find weed to have amazing initial effects on reaction time, coordination and sometimes physical creativity. We play this ping pong game with adapted rules and two balls, basically the ultimate test of coordination, timing and reflexes. Some of the players definitely get a boost after taking a weed break, as attested by objective, sober onlookers. I've returned balls I definitely could never get if I wasn't blitzed
Again though, I find that weed reduces focus,so if youre not focused on the task you wont get any benefit and like it will be a detriment.
I find the notion that weed reduces physical confidence comes from the fact that people simply don't care, or don't know how to use the high when it comes.