a note on sweeps

or: how to make sweeps work

(adapted from teachings by sensei joe schoenig)

the mechanics of sweeping are, in essence, quite simple. i'm certain that this short article won't be of much use to many karateka, since it will add nothing that they don't already know, and if this is you then good for you; you're ahead of me. but i'm a big supporter of there being information available to people who go looking for it, and hopefully this will be useful to someone at some point.

on sweeps

i'm a sweeper. that's not to say i'm great at it, but i do regard sweeps as an extremely useful tool in competition kumite. and if ever i am called into an actual fight, i have no doubt that some version of a sweep will be part of my plan to escape (or, heavens forfend, overcome). that being said, only a few years ago i was fairly terrible at executing sweeps. these days i'm probably a little slower and weaker than i was then, but my sweeping has improved dramatically due to a greater understanding of the mechanics of sweeping that i previously lacked. with thanks to sensei schoenig, this is a short description of the realisation i came to about why sweeps work, and consequently how to make them more effective.

when i refer to sweeps here, i shall almost exclusively be referring to ashi-barai attacking the outside of the opponent's front foot, either by stepping forward with the back foot if both fighters have their same side forward, or by using the front foot in a smaller motion from opposite stance. i will stay within the context of semi-contact free kumite, though clearly there are extensions to be made for other sweeps and other situations.

firstly, a justification: sweeping is incredibly useful because it attacks an entirely different part of the opponent's body to everything else you do in competition. all punches and kicks must be aimed at chudan or higher, and so blocking or evading a sweep requires a totally different skill to blocking or evading punches or kicks. there are two upshots of this, both favourable to the sweeper: the opponent may not see the sweep coming because they are not looking for it, and the opponent may not have developed the level of skill in avoiding sweeps as they do for everything else. these reasons alone should be enough to convince the karateka that sweeps are worth investing time in.

1. the obvious bit: sweeps work by moving balancing points

sweeping is fundamentaly different to throwing; the latter requires you to move your opponent's centre of gravity outside of their balance shadow, whereas sweeping requires removal of the balance shadow from underneath the centre of gravity. the consequence of both is essentially the same, of course, but there is a subtle distinction which points to one of the major misunderstandings of sweeping. sweeping does not require a shifting of your opponent's centre of gravity, and thus in principle is physically much less demanding; a torque, rather than a translation, is being applied. causing a rotation of the body, applied at the periphery ('taking the foot away'), takes much less work than displacing the whole body. thus: sweeps require hardly any effort at all to work. they can be made more forceful to more dramatic effect, but the basic act of sweeping requires essentially no effort.

figure 1: the difference between sweeps and throwsfigure 1: the difference between sweeps and throws
figure 1: sweeps (eg ashi-barai, above left) remove the balance points without altering the centre of gravity of the opponent, whereas throws (eg tai otoshi, above right) move the centre of gravity. throws may also attack balance points.

2. the subtle bit: sweeps only work if balance cannot be recovered in time

we all understand the first part, but failure to understand this second part is the dominant reason that sweeps fail. it makes perfect sense, of course; we all know at an intellectual level that if the opponent has time to recover, then the sweep will be ineffective. this is a strong argument for having a swift follow-up attack, which is never a disadvantage, but also points to the need for correct timing in the sweep.

combining these two points then, the timing for the sweep must not be when the opponent's foot is in contact with the floor, since the extra force needed to move the foot during this time renders the sweep difficult (if not impossible), nor when the foot has plenty of time to recover to a balanced position before it returns to the floor (blue area). if you consider that most kumite fighters in competition today have a 'bouncy' style, which is often fairly rhythymic, then the height of the leading foot can be approximately graphed (figure 2, below). when the foot is in contact with the ground (red area), the foot will be hard to move. the optimum time to take the foot, then, is as late in the downward trajectory of the foot as possible, just before it meets the floor (green area). at this point, there is no time to correct for any movement of the foot, and the opponent's centre of gravity has nowhere to go but down. in short: sweep too early and the foot can be recovered, sweep too late and the sweep may not take the foot at all.

figure 2: optimum sweep timing

obviously these are guidelines only, and it is easy to see that a more committed sweep that displaces the leading foot a greater distance can be applied earlier, and that a more forceful sweep (or perhaps for a lighter opponent) can potentially still work after the foot has landed. in prinicple, though, timing the sweep to contact at the last moment will give the least telegraph, and require the least work, with the foot only needing to be moved a few inches (cf the note on balance) to upset balance, or a few more to remove balance altogether.

further notes on sweeping:

1. sweeping is not kicking. there is no sharp 'impact' to the sweep, since this will act to stop any follow-through of your foot on the target, and make recovery much easier for your opponent. it also limits your control of your opponent's foot by massively decreasing the contact time. instead, the toes should attempt to 'grasp' the foot/ankle and hold on to it as it follows through (figure ***).

2. sweep into the void. the most efficient way to move the foot in order to disrupt your opponent's balance is the shortest distance to the edge of their 'balance shadow',and this direction can be referred to as the void. this is the precise direction you think it is; at right angles to the line connecting their feet. be aware, though, that this direction is back towards you (figure ***), rather than the more natural lines your attacking foot wants to take. the correct trajectory for your foot thus highlights that the point of contact is at your furthest distance, hence the sweep can be initiated from a long way away. the most basic sweep is similar in movement to judo's ko-soto-gari throw.

3. keep the sweep down. firstly, on your approach, lest you swing up (as the leg will want to) and inadvertantly attack the knee, which is dangerous and illegal (because it is dangerous). by keeping a bend on the back leg and increasing it as the sweep goes out, you can keep your foot low (figure ***). secondly, on the follow-through, else you are giving more time for recovery and may even allow the swept foot to convert to a kick by lifting it. take the foot, but also use the sweep to place it somewhere you want it, rather than leave it to chance.

-neil jerome, 2010

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