What options do you have against a bigger opponent charging like a lineman? (not just punching or kicking, but using his body-weight to overthrow you).
I note your question is tagged with just
self-defence - what I explain here can be applied whether you are practicing an established martial art or just a bunch of self defence type moves.
There is an exercise in a number of Japanese arts (karate, ninjutsu, aikido and more) called Tai Sabaki. It involves doing the same repeated sequence of moves (whatever is chosen at the time, not like kata) while pivoting at the start of the sequence. Here is an introductory Yotube link, you can explore from there. The purpose of the exercise is to turn and face - or in your case deflect and face - so you are off the original line of attack, giving you a better angle to defend from.
In general though you want to avoid meeting the opponent head on. You can meet them head on if your technique is good, but this can take some training to master. For example, rather than delivering a mae geri (front kick) to the thigh from directly in front of them as they charge, you will have far more success if you step on a 45 degree angle and deliver the kick from there - this is what tai sabaki teaches you.
You will also find that Aikido specifically has ways of dealing with this, many of its throws are based on using the opponents momentum as part of a throw (once again this involves turning as you execute a movement, just like tai sabaki). If you are a practitioner of a striking oriented system you can still practice aikido - you will find it complements whatever you are currently training in and expands your arsenal of moves while teaching you better positioning and movement.
You need to do something like Wrestling, Brazilian Jiu Jitsu or Judo. These arts are great for taking a persons force and using against them. Ignore all these stupid wing-chun kung fu type of martial arts. I've trained in wrestling, BJJ and Judo against guys who are smaller than me (I'm 6ft2 92KG) and had my ass kicked by guys who have great technique alone.
Loaded question. Depends on many factors.
A) Do you have the option of running (and do you think you could outrun him)? If so, do.
B) Is he within kicking range (and are you a strong and accurate kicker?) A kick to a vital area (groin, ribs, solar plexus if you can reach) would be well worth your trouble. This has the added advantage of stopping him before he gets too close. Also, don't underestimate the value of a good stop kick to the shin. A stop kick is a kick used to prevent kicking or halt forward momentum (such as a heel kick to the shin).
C) If this person is barreling toward you like a lineman (a stupid way to fight), he probably intends to grab you and control you through grappling. You need to be effective at counter-grappling, that is, be able to grapple enough to escape. Biting, eye gouges, testicle-grabs, are all fair game (if this is a self-defense and not a sparring situation). If this person is a trained grappler, tap. No joke, tapping may trigger his unconscious response to let go, at least enough for you to get some breathing room and/or leverage, but don't count on it.
D) If you can, sidestep. He's barreling toward you like a bull, so be a matador. While you're sidestepping, make sure to hit him hard, fast, and multiple times, then run away as fast and as soon as you can. Be ready for him to put you back in his cross-hairs fairly soon though.
I think this question requires clarification. What is the specific situation in which someone is just charging at you like a linebacker? Who fights like this? I can clarify my answer if you can clarify the question.
Chances are, this isn't just someone charging towards you. This is what I characterize as "The Berserker". The Berserker is a guy who goes crazy on you. He's going to charge at you, probably screaming, flailing his arms around, and doing all kinds of kicks mostly at thin air as he's coming towards you.
The Berserker is one of the hardest, scariest types of attacks to defend against. Most martial arts have a pitiful, unintelligent answer to this. You're typically going to hear something like this: 1) Evade, don't be there, make him chase you. Or 2) come straight at him (maybe even with the same ferocity and energy). Both these strategies don't work.
If you try to evade a Berserker, he will merely turn and follow you. If you can run and get out of there completely, great. That's common sense. But most of the time, a Berserker doesn't give you much room and time to evade.
One Berserker I had to deal with once (unsuccessfully!) in my early college days was when I was in a narrow hallway. There was no room to evade left or right. And turning around and running wouldn't have worked, since he already had a head start on me going towards me. He would have easily caught up with me, and my back would have been turned to him. I opted to kick at him, but he easily blocked it, got in some punches to my head and body, and took me down. I was helpless. That made me think A LOT about this scenario.
That leads me to the second strategy I listed above: Confront him head-on with kicks, punches, knees, etc. Basically, you're taking an offensive strategy here. As I found out, it just doesn't work!
A Berserker will merely put all his weight into you. And you might land one or two strikes, but a Berserker is someone who's flailing around rapidly. He's going to nail you five times for every one you land. Don't fool yourself into thinking your martial arts expertise will allow you to make one good punch or kick that will just put him down immediately. It won't.
And if you yourself actually go into Berserker mode to counter his Berserker mode, then both of you are getting seriously hurt. There's no telling who will win. This is just a stupid defense. It could work, but it's not intelligent.
If you insist on becoming a Berserker to defend against a Berserker, make sure you are constantly moving around, mostly sideways, not back-to-front. If you stand still, you're giving him a target he can lock onto. By not standing still, by bobbing your head around, you're making it real hard for him to target you. While you're doing this, you need to be throwing punches like mad. Don't focus too hard. Just flail your arms like he's doing. Because statistically, one will land, and that's all you need. Your body movement is just buying time for one of your strikes to land.
But as I said, that's not intelligent. And it's maybe just as likely he'll hit you before you hit him.
No, the way you deal with this situation is by practicing this scenario over and over again. This is worthy of practicing a lot, because it comes up a lot in real life. And if you can get comfortable dealing with this kind of an attack, it will spill over into just about every other scenario you may encounter.
If the Berserker is coming at you flailing his arms and legs, but he's doing so slowly enough that you don't need to sprawl, then you can duck in under a punch (accepting that you might have to eat some hits to your face), and go for a take-down. You need to get up close with him, pressing your shoulder into his chest. Hold on to his torso with both hands. Tuck your head down. Stick to him. This will prevent his strikes from doing any real damage to you. Next, take your leg and hook it behind his leg. Then take him down.
If the Berserker is coming at you too fast for a take-down, you'll need to stop his advance by sprawling, followed immediately by anything that will take him down. Think about doing a single leg take-down, a trip take-down, a whizzer, etc.
Sprawling and duck-and-shoot style take-downs are your bread and butter. Practice these often.
So in summary, the basic strategy here is to control his forward advancement first, and then take him down. Once you have him down, he has lost his mobility. He's not as much of a threat to you and others at this point. You can then use that as an opportunity to exit, or you can go on to submissions and pounding.
This is a high risk, high stress, no time situation. It's scary. Your adrenaline will be surging. Your accuracy will be greatly reduced. Your ability to think will be mostly gone. Many things can go wrong. Even when things are going right for you, you'll probably still take some strong hits. That's why this is something you need to practice.
Learn to sprawl.
High school wrestling 097; go learn to sprawl. A good sprawl will move you out of the line of attack.
The real thing you need to though, is have guys charge at you with the intention of taking you down/whatever, and you doing a defense on a regular basis, say every day at 6pm at your local wrestling/grappling/Bjj school.
A strong jab (aka a "straight punch") or headbutt to the nose or the tip of the chin will momentarily stun your opponent, giving you time to decide to fight or flee.
You won't be thinking clearly enough to perform the five-point-palm-exploding-heart technique from Kill Bill or something you saw on a 70's kung-fu movie. The simplest, most effective way of dealing with an overpowering opponent charging at you is to stun him and make him think twice about what he's doing. Unless he's a professional boxer, he won't know how to deal with hard contact to the nose and will likely be shocked into incapacity. It also doesn't hurt that his eyes will be watering and there will be lots of blood. Ironically, a good boxer won't be charging you head-on anyway, so it's a pretty safe fall-back technique for this type of situation.
Source: personal experience. LOTS of it.
This actually happened to me. I ducked and threw my side into him very low causing him to flip over me. The end result was a concussion from his head meeting the floor, and 2 broken ribs for me, from his knee. Do not do what I did!
If you can just avoid the charges. It uses a lot of energy to charge like that. Tire him out by letting him do his thing. At this point I would just leave the situation I I could.
While I appreciate the fancy, exhaustive answers here, there is really a common theme that rises to the top:
If you aren't there, you can't get hit.
Move. Don't stand their waiting to do something cool. Even if you can't move completely, try to move so you can trip him. There's no need to do anything other than that here.
Chances are, if he's charging, you have some time to get out. Note the Tueller rule: An armed attacker can cover 21 feet in just 1.5 seconds. That should be enough time for you to decide whether to meet and potentially get bowled over by the freight train, or scram.
There's obviously some doubt as to whether the question is what can an untrained defender do or what should a reasonably competent martial artist do. For the former, assuming the fight's unavoidable I'd recommend stepping in suddenly and deep to catch the attacker before they're expecting engagement, using a palm strike, elbow, front thrusting kick or knee - whatever you think you can make work.
For a trained kicker - I recommend the side thrusting kick...
Like several other respondents, I've also been attacked in this style... someone charging from 15 or 20 metres away. I stepped in with a gliding side thrusting kick - the footwork moves you in a couple metres and the kick reaches out considerably, so you're meeting the opponent four or five metres in front of the point they expect to be hitting you (possibly more - they probably expect you to back away), when they're basically in the middle of a running motion or just starting to tuck down for a dive/tackle. Their own momentum makes them defenceless. I kicked through his chest lifting him off his feet and throwing him backwards to land on his back. He was about 10cm taller than me and of a solid "footballer" build. I had practiced this kick extensively against heavy swinging bags and other targets. You might doubt the kick could have enough power, but there was little feeling of impact - the kick can very easily do this. I deliberately held back from full "snap" power in my kick (i.e. reducing the peak power at impact and pushing him more / I tend to have to be angry to lash out with real intent to maximise damage, which is a rare thing for me), and I was wearing soft sneakers, but it took him a good two minutes to stand up, and he made no attempt to continue the fight.
I used a "checking" kick variation of this technique against another charging attacker - albeit smaller than me this time - he'd just robbed a shop and was trying to get to his car: he was pretty determined to land a "good one" quickly or scare me off - telling me he had a knife while searching his pockets - and after a couple ineffective swipes at me he charged and I checked his forward progress with a side kick to the hip - not trying to knock him down - again he turned and sprinted for his car. I was trying not to hurt him as I had been walking past the outside of the store and it was my girlfriend who said "go stop him, Tony" - I wasn't sure what he'd done and was initially planning just to talk to him. One of the times I had an endorphin reaction in a fight - you're so mellow it's hard to be aggressive, which isn't necessarily a good thing, but everything slows down nicely and it's so easy to control the situation.
So - side thrusting kicks are recommended. You can cover ground quickly to hit them at an unexpected point in their approach, the leg reaches out much farther than their fist could and your head's way out of their reach when you make contact. But, not many arts do them particularly well. See 2:50 onwards in this tutorial if interested - https://www.youtube.com/watch?v=uTtyTOLqnoc
Aikido might come in handy. Since your opponent is strong and charging towards you, you can't use a stop kick or any other kick above the waist since it makes you unbalanced and you will be overthrown even if you landed a perfect kick.
So the best option would be to move away at the very end or use your opponent's speed and make him fall. One thing you can do is you can go down and kick him below knees to make him fall but this should be done at the very last moment.
In aikido there are moves which will use the opponent's force to make them. So you can try it
In Aikido, i learn that i could overcome bigger opponents/partners with huge charging forces by
Grabbing their shoulders on both side and moving downwards and backwards while twisting your body a little.
Moving sideways or offline at the last minute as they charge in.
A knee to the head as they bend down.
Push their heads down as they charge in. In all honesty, timing is very important as moving too soon would allow them to change their direction and moving too late would result in you ending up on the floor.
We do drills in the dojo on these situation and i find the most effective one for me is either pushing or chopping their heads(back side) as they charge in, or basically just knee-ing them.
i have learnt a few martial arts including systema - the Russian martial art - which is mainly focused on using the attackers momentum against him. in this particular case, since he's running at you, you can simply just step aside and trip him when he reaches you, and because he's expecting to meet resistance his momentum will carry him down where you can then deal with him there. hope this helps!
I hate to add to an already extensive set of answers covering just about everything but I wanted to add a small amount of perspective as a soldier on how you might deal with this situation based on personal experience.
I have to agree with many points made by others. 1) Steve is right, you are often dealing with a berserker or at least someone who is possibly without skill and is using the intimidation of their size and "crazy" to try and blitz you.
2) Funky is correct, you need a discipline in your bag that deals with momentum and using the enemy's force against them. Wrestling does that, so does Judo and definitely Jujitsu, BJJ would definitely qualify as an excellent option.
3) This brings me to slugster's point about a discipline such as Aikido which would certainly be excellent in this situation. As would any that deals with force redistribution and momentum shifting.
4) However, I would be very careful about Juann's advice, while a well placed jab with enough force CAN drop the target, if we stick to your provided facts of smaller target being charged by a bigger target linebacker style, chances are you won't be able to deliver a focused and powerful enough jab to stop him and you will likely end up busting your fist or wrist in the process and have the wind knocked out of you from the impact of his head/shoulder into your chest and hitting the ground.
5) Lastly, Wudang has a point, this leaves itself open to much interpretation because unless one is standing in front of a given situation, its hard to know what will work best. This is why you need to make sure you are well rounded and generally prepared in the hopes that you will have what you need to deal with each situation as it comes up.
All that being said, as someone adapt to such fights, I would wait until he was within arms reach, shift slightly to the side and grapple the back of his neck or swipe the back of his head to force his momentum further forward making him land on his face or if I am lucky to be standing near a hard object (pole, well, car) I can have him rammed into that. Once on the ground, I have more options to keep him down. If however more on the novice side, this would be a great time to start running to safety and avoid a prolonged fight altogether. Depending on the height disparity, you can also shift your center of mass downward and go for a leg sweep which would get him off the ground and his momentum would carry him into a pretty good face plant. However you approach it, its about understanding the situation and that comes with a little knowledge of physics and disciplines that use it most effectively. Once size doesn't fit all and that's why you need to expand your bag of tricks. Hope this helps tie it all in for a you a bit.