When the center men of the line are rather light, if the backs are heavy and slow, the advantage will still be in attacking the openings between the center and guards and between the guards and tackles; for, if the backs and ends mass on these places, as they can do quickly and powerfully, they can still force a few yards at a time, and now and then break through for considerable gain. When well massed, this can be played even against the strongest centers. All that the rush line will need to do is to hold their men momentarily until the backs get under headway, and the combination of so much weight and power will be sure to make advance when well directed. If it be remembered that the advantage is always with the side which has the ball, and if the players, though checked now and then, go into each play with undaunted courage, advance will surely be made.

As a general rule, when a team has light, swift runners behind the line, they should lay the emphasis on plays around the end and between the ends and tackles. Not that they should confine themselves to those points of attack, but it would be foolish for a team composed of such material not to perfect the plays in these parts of the line, because of the ability of the backs to move quickly to these remoter places. Such men, too, are not so well built for the hard, plunging work in the center, and will probably stand less of it, and be less effective, than heavier backs. This of course depends in part on the build of the men, but in general it is true.

But even if the backs are equally good in plunging into the line, it would be better policy to keep the line spread out, for no runner can make much gain through a close line. Swift drives through the line can be made frequently, and are usually very telling when the line, being spread out, is opened up for these little backs to come darting through. But if the backs and the central part of the rush line are both light, while those of the opponents are heavy, the end style of play must of necessity be depended on, or the opposing rushers will be able to resist the plunges. Furthermore, it will be exceedingly hard to make holes through the line, and, in fact, even to hold their opponents long enough for the backs to get up to the line.

The question of what shall be the proportion of end plays and plays between the ends and tackle, to the plays through the other four openings in the line depends, of course, very largely on the backs. The composition of the rush line as to strength and skill, especially the center, guards, and tackles, also affects the proportion.

On the ordinary college and preparatory school team, the relative effectiveness of an end game to a center game would be much smaller than where the teams are better trained, simply because the risks are larger; for, while the defense against well executed interference would be much weaker, the attack also is much weaker.

Every end play and play between the tackles and end is attempted with a much greater risk from actual loss of ground, or with a loss of a down with no gain, than are the plays in the center. The reason is that the rushers are given time to break through the line while the runner is moving out to the point of attack, and unless well protected he will not reach the opening.

Further, this movement for a considerable distance is almost entirely sidewise before an advance can be made, while in the plays in the central part of the line the rushes are made nearly straight forward, except when the rushers take the ball, and the runners scarcely ever fail to reach the line. The times when there is no gain whatever and when there is an actual loss are comparatively few, for the runner, catching the ball at full speed, is up to the line in an instant, and then it becomes a question how far he can advance beyond that point. Taking these elements of risk into account, it would seem that the proportion of plays at the end to plays through the line should not be larger than one to three, and oftentimes less, even where a team is able to use both styles effectively. The only occasion for a larger use of end plays than this would be when the runner seldom fails to reach the line, and is usually good for a gain. In that event the large element of risk has been taken away, and the proportion of use should then depend on the relative amount of gain which the trials have shown can be secured from each with the least expenditure of energy.

Right here it might be well to add that it requires more skillful generalship to know when to use an end play than when to make a play through the center. It is only occasionally that the ball is down so close to the side lines that all four openings in the center are not available on account of running outside the line, while it is frequently the case that the ball is down near enough to the side line to limit the end play to one side, that is, to two openings. Nor is this enlarged space on one side of the field sufficient compensation for the loss of the two points of attack, but it adds to the science of the game, as it requires more varied tactics and maneuvers.

It is poor tactics to keep trying end plays when it has been clearly proven that it is not possible to make them and that there is a likelihood of a loss in the trial. If it seems best to try the end for the sake of keeping the opposing line spread out so that the center plays can be made more successfully, the most propitious times should be selected. It should never be on the second or third down, because the risk of losing the ball by failure to gain the requisite five yards would be entirely too great.

There are times when an end play should not be used at all, or very rarely, on account of the risk involved; as, for example, when the ball is being carried out from under the goal where it has been forced by the opponents. Anywhere within the fifteen or twenty yard line it is much better to trust to bringing it slowly out a few yards or feet at a time, sufficient, perhaps, to secure only the requisite five yards in three trials. Beyond the twenty-yard line and up to the thirty-five-yard an end play should be tried only on the first down, or, in rare instances, on the second down, unless the risk of losing ground, and subsequently the ball, is worth taking. In such cases the possession of a powerful punter behind the line, who could place the ball well out of dangerous territory if necessary, might be a sufficient reason for attempting a long kick down the field. It does not seem, however, that it is necessary to run any risk of losing the ball if there is good reason for not playing a kicking game, for there will be ample chance to try an end play on the first down. Mistakes in generalship are frequently made right along this line in nearly every game which is played, an end run being sometimes tried on the third down when there is less than a yard to gain. Better gain the yard or two by the surest ground-gaining play and then try an end run on the very next.