Under most circumstances, golfers are urged to swing the club with some restraint. Hitting a ball for distance and keeping it straight is more about mechanics than it is about velocity. However, there are some circumstances when the golfer can unbutton his top button and let it rip as hard as possible.
Open it up on a long par 5 hole that has a wide fairway. The problem with swinging hard to try to get those extra yards is that it can lead to a mishit that goes outside the fairway and makes the next shot more difficult. However, on a long hole with a wide fairway, you have a chance to bash the ball. Take your normal grip, begin your backswing with some urgency, rotate your hips through the ball and come through hard with the club. If possible, keep your head down.
Swing hard when you are in the rough and you have to drive your club through high grass. Use a medium iron such as a 4- or 5-iron. These clubs excel at digging the ball out of the grass and back on to the fairway or close to the green. It is important to come through the ball hard or the grass will hold up your club. Take your normal backswing, but come through the ball extra hard to get the ball out of the high grass.
Drive your ball hard off the tee on a long par 3 that is guarded by a bunker or a water hazard. On a 240-yard par 3, you may see the green is guarded by water of a large bunker, but it has plenty of open territory behind the green. In a case like this, you are much better off going past the green than coming up short. If you can hit a ball 250 to 260 yards, you will want to take your driver and hammer the ball as hard as you can to carry the hazards. If you land on the green and then roll off of it, you will still be in a good position to recover.
Swing hard when you want to go for the green from the fairway when you are playing on a course with a lot of roll. If you are using a 3-wood from 240 yards out, you may want to go for the green because the course is accepting of low shots that bounce and have excellent carry. By standing with the ball slightly behind your front foot, rotating your hips fully and coming through the ball with velocity, you just may have enough distance to reach the green.
Swing your putter hard when you are more than 60 feet from the hole. Some greens are very large and you may find yourself as much as 100 feet from the hole. This is not the time to try to see if a touch putt will get your ball to the hole. You have to give the ball a firm stroke with a strong follow through if you are going to come close to reaching the hole.
Tips & Warnings
Swinging hard is usually not a good option. Only do it occasionally or when your ball is trapped in high grass.
You are usually better off with a calm and controlled swing than letting it all out to gain a few more yards.