The Quick Release brake works similarly to the Quick Release skewer described here – via a cam mechanism. Most of the road bike brakes made after the early 1980’s have a Quick Release built in so that the brakes can be opened up to facilitate the removal of a wheel. Many people own bicycles with this type of brake, but are unaware that their brake may be in the “open” position that dramatically decreases the power of their brakes.
Take a look at your brake and see if it has an identifiable lever near one of its pivot points.
PHOTOS OF BRAKES WITH LEVER + CLOSEUPS
Try flipping the lever either up or down. As you do so, watch the brake pads and see if they open up or close in closer to the wheel. If the lever doesn’t move, try lubricating it with some standard bicycle lubricant. Before you ride the bike, make sure that the lever is securely in the closed position and the brake pads are close to the wheel.
LEVER OPEN LEVER CLOSED