1. The throw on-the-run is a skill that has to be developed through much practice and repetition.
While running, the passer must twist his torso perpendicular to the target in a quick, cocking motion. Many passers do not get their shoulders far enough around – while still running – especially when sprinting out in the opposite direction of their passing arm.
For every action, there is an equal and opposite reaction. The throwing motion and subsequent release must immediately follow the cocking motion. This uses the momentum of the motion to assist the throw, like loading and releasing a spring. Many times QBs hesitate, creating two distinct motions, back and forth, which depletes the momentum and causes the pass to sail or flutter.
When running in the same direction of the receiver, the passer does not have to “lead” the receiver. A lot of quarterbacks don’t realize this. It’s simple physics. The ball is already traveling that way when it’s released, so it naturally “leads” the receiver.
http://www.spreadoffense.com/ssp/sprint_out_pass
2. "he threw with a very tense upper body and he squeezes the ball hard, which can cause the ball to flutter or sail on him at times"
Tom Luginbill, ESPN
http://sports.espn.go.com/ncaa/recruiting/football/news/story?id=4098507
3. My criterion when it was windy was to throw a spiral. ‘You can’t rush it, either. Slow down the motion. When you speed up and try to power the ball, you give up a certain amount of control. Your accuracy definitely suffers. You want to be nice and smooth. You’ll get through the wind better than if you try to muscle it.
Overgripping is the most frequent mistake I see among quarterbacks at all levels, including the pros. ‘I found the harder I’d squeeze, the less control I’d have. When you throw, your arm should move like a whip. It can’t move that way when the muscles are tense.
Phil Simms, New York Times
http://fifthdown.blogs.nytimes.com/2009/01/15/how-to-stop-downward-spiral-for-eli-manning/?apage=2
4. If you’re interested in learning more about how to throw a tight spiral, you can consult this article in The Wall Street Journal
http://online.wsj.com/article/SB119707054348217657.html.
Excerpts:
Physicists say a football needs to spin to be gyroscopically stable, but as soon as it’s airborne, wind and gravity will try to knock it from its axis and make it wobble like a slow bicycle. That a quarterback can throw one of these things 60 yards and hit a moving target “is just amazing,” says William Rae, professor emeritus of aerospace engineering at the University at Buffalo.
Simms has written a book called “Phil Simms on Passing” and tutored several promising quarterbacks (at no charge) from nearby schools. If he’d known what he knows now while he was still playing, he says, “I would have set records.”