There are also times in the game when a standard mark is inappropriate, and something different is called for. Being able to recognise these situations is important, and knowing how to react to them even more so.
The marker is allowed to stand one disc width from the thrower, but it is not always best to stand this close. Against weak throwers, it is fine to pressure them by standing as close as possible. However, against strong throwers who enjoy throwing inside-out and break passes, it is often best to drop back about a metre. The advantage of this is that there is an extra fraction of a second after the throw for the marker to get their hand in position for a block, particularly against the inside-out pass. In theory this may seem insignificant, but in practice that fraction of a second is often the difference between a throw going under or over the marker's hand and the marker getting the block. The other advantage is that if a block is made, it is much less likely to be called for a foul because the disc is more likely to have left the thrower's hand.
On the down side, there is less pressure on wide throws to the open side, and it is a little easier to break the force with a wide throw since the marker has moved their body away from blocking the break side. The advantages appear to outweigh the disadvantages, however.
A strike occurs when the marker temporarily switches the direction of the force. There are a couple of instances when this comes in useful.
The first is when there is a high stall count on the thrower already. If the count is at 8 or 9 it is obvious that the thrower will have to throw almost immediately. The usual throw is a huck on the open side. By employing a strike, the marker may be suddenly in a position to block this throw, since they are now standing on what was previously the open side. There is then a good chance of a stall, throwaway or block.
The second is called by one of the defenders. If the man being defended by one of the defenders gets free on the open side, the defender may call "Strike". This tells the marker to switch force for a second or two to stop the easy pass to this cutter. After a second, the marker will switch back, by which stage hopefully the defender will be close to their man again, or the pass will no longer look so inviting. This is not a good call to make if there are also men free on the break side, and it should be used carefully. The marker needs to be listening carefully to make sure they switch immediately.
Along with layouts, hand blocks are one of the big psych-inducing plays in a game of Ultimate. However, hand blocks are not something that can be generated at will, despite some people's thoughts to the contrary. They are a combination of good positioning and balance, support from defenders, quick reactions, the right (wrong??) throw, and a certain amount of luck. As well, they are not something that should be aimed for. Actively attempting hand blocks tends to be a sure fire way to let the thrower get an easy break.
The best way to improve your chances of getting hand blocks is simply to improve your general marker defence. A hard mark should make any kind of break throw a risky proposition at best and a guaranteed turnover at worst. A hard mark is not much use though unless the defenders are doing their job.
If the thrower always has an easy open side throw, not even the best marker in the world is going to get a hand block. As a result, hand blocks are as much an effort of the defenders as the marker.
The number one mistake when marking a good player is to mark too close. Marking close is effective against inexperienced players because they are usually too intimidated to pivot well and get around the force. Most good players, on the other hand look at a close mark as being a license to break the force. I have found that standing back about a metre from the thrower has improved my marking a great deal. The distance to stand back is a personal thing, but it gives you a split second of extra time after the thrower releases the disc. This allows you to move your arms, and may be the difference between getting the block and having the throw go over or under your arm.
The other reason to stand back is to do with fouls. If you are a metre away and get your hand on the disc, it is unlikely that the disc is still in the thrower's hand. If you are right up close and get your hand on the disc there is a good chance that it is still in the thrower's hand, and you will have a strip or foul called against you. Standing off a bit reduces the chance of a block being called a foul.
The other things to increase chances of hand blocks are standard things to improve marker defence. Keep your weight low and between your feet. This improves your balance, and makes it much easier to slide around to either side to stop a throw. Have your knees bent, and move your whole body and not just your arms when covering the thrower. It is too easy to keep your feet still and simply reach out with your arms. The further you try to reach, the less balanced you are and the higher the likelihood that you will not be able to follow the thrower as effectively when they pivot.
Watch the disc, the eyes of the thrower and their navel. The eyes tell you where the thrower wants to throw. The navel shows you where the centre of mass of the thrower is. They will not be able to pivot without moving it, so it is better than being faked out by head fakes, body fakes and leg fakes. The disc should be watched with care. You need to watch the disc to be able to move your hands to get a block, but you also need to avoid being taken in by disc fakes.
Keep your hands low. This is most important for the hand on the open side. Most break throws on this side go under the hand of the marker. The positioning of the other hand depends a bit on your knowledge of the thrower. If you think they are likely to throw a hammer or high backhand, then keeping that hand high is a better idea. Otherwise, keep that hand low also. It tends to take longer to throw these high throws effectively, so you can always move your hands if the thrower winds up for one of these.
Finally, if the thrower goes for a hammer, jump for it. Even if it is a fake, it usually takes them almost as much time to recover as it does for you. Letting a hammer out on the break side is no better for your team than a forehand or a backhand.
So, in summary, the main points are :
Above all, remember that marking is an active process, and not a passive one. You are trying to prevent the thrower from getting an easy pass away - make it hard for him. Keep moving, keep your hands active, but dont let them break.