Very often played straight in manga and anime, where the trainee stands for hours under the weight of a raging waterfall. Very often subverted as well, where the trainee has something bad happen to him due to this (such as in the anime adaptation decay of Akazukin Chacha, where the joke vampire villain catches a cold that he hasn't shaken off by the time he tries to take revenge on the protagonists).
Subverted in Fairy Tail, where Team Erza goes to the beach to train for 3 months, but end up partying. They then get a free instant powerup from Ultear's Time Arc magic
Justified slightly. They did plan to train, but Lucy's Guardian Spirits decided to celebrate their return by taking them into their world. Unfortunately for the wizards, one day in the Spirit world exactly equals 3 months in their world.
Train Heartnet, from Black Cat, underwent hellish training, including one-arm pushups on his thumb, to prepare for pistols.
Pretty much all sports anime/manga features characters who go through training from hell one way or another. Examples:
The Ur Example in anime is Kyojin no Hoshi (Star of the Giants): protagonist Hyuuma Hoshi was put through hellish training as a baseball player since childhood by his father, a former player. The most iconic part of the training was a special spring-loaded harness Hyuuma wore beneath his , which made even daily tasks part of Training From Hell.
Eyeshield 21 featured torturous training schemes such as Hiruma's "Tower From Hell", where potential new recruits to the Devil Bats had to carry ice to the upper observatory of Tokyo Tower... on a hot day... with a trip through a room full of space heaters turned on full-blast along the way and many MANY other traps. Later, the team gets introduced to Kurita and Hiruma's sensei Doburoku, who puts them through "Indian running" where the last person in line gets doused with hot water if they don't hurry to the front, and the "Death March", where the entire team ran from Houston to Las Vegas in 40 days, with the linemen pushing a truck, the receivers getting chased by Hiruma yelling out passing formations and shooting his gun at them> Sena kicking a rock in a variety of patterns (straight, zigzag, two rocks, etc.).
The Death March, by the way, is an example of training that is an active danger to the athletes partaking in it; a previous attempt by Doburoku resulted in a career-ending injury.
Banba of the Taiyo Sphinx underwent some harsh training of his own in preparation for the Kanto tournament. While the details are never revealed, it left him with scars all over his body.
This series takes the name of this trope quite seriously, as nearly every training the team endures is said to be "from Hell" in the dialog. This is in keeping with the team's "Devil" theme (and the demonic appearance and mannerisms of team captain Hiruma.)
Lampshaded in Slam Dunk, when just before their game with Kainan, Ryonan's coach Taoka tells his boys to take a moment to remember all the training they have done so far. Needless to say, the team (from the plucky assistant Hikoichi to the powerful captain Uozumi and star sub-captain Sendoh) is utterly revulsed by the mere memory of the sheer horror they went through, and are all but grateful when Taoka awakens them from their reverie.
In RRR, the protagonist, Rikitarou, has to make it from beer bellied slacker to sculpted rock star in one month, and then into a pro boxer in another three.
Parodied in The Prince of Tennis: the training methods devised by Ryuzaki and temporary manager Sadaharu Inui apparently look normal, but if one or more of the players fail to accomplish them, they're forced to drink repulsive concoctions prepared by Inui as punishment. Actually, his "juices" are so infamous that everyone in the Seigaku team are terrified of failure because of them.
Hajime No Ippo features loads and loads of training sequences (most featuring a shouting Coach Kamogawa). However, the most difficult training that characters seem to go through is their weight management training, which can leave them as shells of their former selves. Special mention goes to Takamura before his match against Bryan Hawk, where he keeps himself 5 classes underweight. It has to be seen to understand just how hard it was. He damn near went insane.
Young Kamogawa hammers tree trunks into a side of a hill. With his fists. And then the damage inflicted on his hands catching up to him in the aftermath of his next boxing match, ending his career as a boxer.
Tiger Mask, both the manga (1968) and the anime series (1969) involved cruel methods of training used by the inherently evil "Tigers' Cave". The training included wrestling with pumas and gorillas, wrestling with lions using only the legs (the stated objective was to get Murderous Thighs), push-ups on the legs with enormous weights attached to the head and spikes under the butt (notable for being an actual training exercise to improve leg strength. Of course the actual version didn't have the spikes...), and being set on fire while wearing a pullover wet with gasoline (the objective was to force the trainee to improve his speed while on the ground, but it came useful when, during a no-holds-barred match, Tiger Mask's opponent started by drenching him in gasoline and setting in on fire: after a moment of surprise that someone would actually do that in a match, Tiger Mask calmly rolled on the ground to put off the fire on himself, then used his own still aflame cloak as a weapon).
Initial D has Takumi's tofu delivery runs up Mount Akina, which he must do every single day...at 4 in the monring...without spilling a cup of water in the cup holder...even if it's raining or snowing. The latter bit pays off when he is pitted against the Redsuns' rain specialist Kenta in the rain, who Takumi smokes so badly that Kenta completely loses sight of him.
When Gohan receives his powerup from the Elder Kaioushin, he has to remain perfectly still for 25 hours. Have you tried to be perfectly still for a long time? It is just as hellish as many other examples here.
Vegeta occasionally hints that he does almost nothing but train, continuously, whenever he is not on-screen. How he had time to conceive Trunks remains a mystery. He'd probably refer to it as "stamina training".
In Dragon Ball Z, Goku, and later Yamcha, Piccolo, Tenshinhan, and Chiaotzu, are killed and sent to the underworld, where they train in 10x Earth's gravity. They are later brought to life with the Dragonballs. Goku also trains in 100x Earth Gravity in preparation to fight Frieza. At high levels of gravity the pressure would make your blood crystallize, which would be fatal. King Kai explained the great strength of the Saiyans partly derives from the fact that their home planet had the exact gravity as his own planet. Saiyans have proved time and again to be a very durable race. Souls given form also seem to be inherently more durable than an actual living person, which might explain how the humans managed.
Additionally, while training to fight the Saiyans, Yamcha, Tenshinhan, Krillin, and Chiaotzu are trained in the room of time and space similar to the X-Men's "Danger Room", wherein they are forced to fight Saiyans who are vastly overpowered and utterly decimate them with energy blasts that shoot through their bodies and are actually painful.
Even in the early Dragon Ball manga and anime, there was PLENTY of this. Kame-sennin gave Kuririn/Krillin and Goku all sorts of tasks, ranging from toughening their hands by making them PLOW A FIELD with THEIR BARE HANDS, to wearing something like 100-pound turtle shells for endurance, to evasion/speed training by tying them to a tree near an angry hornet's nest.
Early on, when Goku still had his tail; it was an easily exploitable weakness for his opponents. Squeezing it caused pain on the level of a Groin Attack and made him lose all his strength. How does he overcome this? He goes to live with monkeys, using his tail for everything. By the time the next tournament arrived, grabbing it had no effect at all.
Dragon Ball Z Abridged has fun with this, with both Mr. Popo and Piccolo. Mr. Popo in particular is depicted as a sadistic sociopath who legitimately enjoys sending the heroes to experience death.
Piccolo: Anyway, I figure, in order to unleash your hidden potential, I'd have to put you in immense physical danger. So I'm gonna throw you at that mountain.
Popo: [when asked where his "students" were] I'll tell you where they're not: safe.
This is averted with the villains who are actually sent to Hell. Souls in the afterlife only get a body if given permission, which is why all the good guys (barring the non-fighters) get sent to the training planets. The villains can't grow any stronger while down there without a body, and thus become pushovers in short order.
Daisuke Niwa's family did this to him in D.N.Angel, although it doesn't seem to be as physically demanding as other cases of this trope. His training was mainly in basic agility and dexterity, not much different than a fairly athletic human adult. His alter ego, on the other hand...
A Flashback scene in Yu-Gi-Oh! ZEXAL shows that Kaito, Gauche, and Droite's training when they young was not only brutal, but dangerous and potentially life-threatenig. Mr. Heartland used a place similar to a Danger Room where they used the card game not against Solid Vision Holograms, but a robot that was trying its best to kill them. (The flashback shows that Heartland even ignored the advice of an aide and turned the robot's setting to very dangerous levels. While Dr. Faker, the Big Bad of the first season, was eventually shown to have a few redeming qualities, Heartland seemed to have none at all.)
In Naruto Sakura's training with Tsunade was this, which is reinforced by occasional flash backs and Sakura cringing in fear whenever someone doesn't realize how crazy Tsunade actually is.
Rock Lee's training procedures consist of setting ridiculous goals for exercises which lead to more unrealistic goals upon failing (ex. "If I can't do 500 push-ups I have to do 1000 sit-ups"). This gets more insane when its pointed out he usually fails his training, but only by a slim margin (usually by only 1 or 2), then barely fails the next one, leading to a ridiculous cycle of him barely failing one objective, then going on to the next, that repeats almost all day. Also, wearing impossibly heavy weights around his ankles during training and, for that matter, actual combat.
A flashback actually revealed this was the entire point of his training strategy. He would set himself a goal he could not reach so he would push himself to his limits, with his punishment for failing to surpass those limits being to push a different limit. If he succeeds in his challenges, he's not improving nearly as much as he wants.
All of Naruto's training requires for him to put his body through hell: To gain his Futon: Rasenshuriken he had to go through weeks and weeks of continuously making clones, and absorbing the combined knowledge which would make him pass out from the knowledge overload. Not to mention when he managed to make the Futon: Rasenshuriken he became at risk for destroying his arm entirely. Then, for Sage Mode he was required to sit still for an extraordinary amount of time. Sounds easy right? Wrong, sitting still is the hardest form of training imaginable since humans are moving animals. If he moved...he'd get the balance off and risk turning himself into a toad stone statue. We see how hard this is: there are HUNDREDS of failed disciples all around Mount Myobokuzan. Only Jiraiya had been able to get to the Toad form of Sage Mode before him, and it was an imperfect state. Finally, to gain his Nine-Tailed Chakra Mode and finally Biju Mode, he had to first fight and defeat his dark side, then defeat the Fox, then learn to control its chakra (its so strong he was at risk of seriously injuring other people, if not killing them, with simple grabs with his chakraarms) and finally, taming the Fox, all of which put him through hell to get that far (and almost losing to the Big Bad to boot due to exhaustion).
Most of Ichigo's training sessions needed to be this brutal in order to achieve enough power in the short time available. Even in his very first Shonen Power Up, being beaten to a pulp by Zangetsu and almost turned into a hollow in training with Urahara resulted in him becoming at least lieutenant class within a couple weeks.
His second major training sequence, learning bankai, compressed what generally takes years of work for those few Shinigami able to achieve it into three days. We don't see much of the actual training, but the injuries Ichigo sustains in the process suggest that it crams all the brutal of many years into those days.
Later, during the Filler Bount arc, Ichigo and friends are tormented by three powerful strangers who force them to participate in sadistic "games." It turns out that the strangers are Mod Souls working for Urahara, and the games are training exercises designed by Urahara to force Ichigo and company to work together as a team.
Also Ikkaku's intense training of the kendo team during a filler arc. It also backfires, mostly, as he ends up severely injuring most of the team. The one person who makes it through intact wins the kendo tournament. Unfortunately, this means Ikkaku is not allowed to fight in the tournament since it then has to end, which leads to his team losing and Ikkaku beating the ever-loving shit out of the entire opposing team.
Ichigo's month-long Vizard training definitely counts as well, given that he basically had to practice wrestling his Inner Hollow into submission over and over again.
Uryuu spends the same period of time in Training from Hell with his father, Ryuuken, in order to regain the Quincy powers he lost through Letzt Stil. Uryuu did not know in advance that this would entail dodging Ryuuken's attacks until he hit his physical and mental limits (which by the way took DAYS)note And Ryuuken had to keep Uryuu in the dark so he would believe his life really was in danger and not hold back, and then getting shot 19mm to the right of the heart with a spirit arrow. This is horrific enough that Uryuu ends up unconscious with a still-smoking brand where the arrow hit him. And then Ryuuken spends the rest of the time until Uryuu runs off to Hueco Mundo with Ichigo and Co. beating the tar out of his son to improve his reflexes and archery skills.
Even Ichigo needs 3 months of time getting kicked around by Getsuga to master the Final Getsuga Tenshou that he uses against Aizen in the climax of the Deicide Arc.
Taken Up to Eleven when it's Kenpachi Zaraki's turn for training, under someone who is a master swordsman and a master healer. Step 1: Attack student with strongest, fastest, most lethal attack. Step 2: Heal the lethal wounds before death can set in. Step 3: Return to step 1. Repeat until student can dodge and counter.
Virtually all of the advanced training methods seen in Ranma 1/2, such as those for the Bakusai Tenketsu (in which one has huge boulders swung at him from ropes), the Kacchu Tenchin Amaguriken (in which the trainee must snatch chestnuts out of a raging fire with his bare hands or, in Ranma's case, piranha from a tank of water). Futhermore, there is the infamous ''Neko-ken'' (in which a young child is wrapped in fish products and thrown into a pit of starving cats), which occurred only because Ranma's father didn't turn the page in the training manual and read that this is a stupid training method that no one should use.
And possibly the strangest method: in order to train for the Parley du Foie Gras (a technique which involves force-feeding opponents so that there's too much food coming in at once and clogging up the works; the book that describes the technique notes that people who rely on it invariably die of starvation, because they're giving all their food to the other guy), Ranma-chan hangs dozens and dozens of buckets of cold water, and kettles of hot water, from the ceiling, then sits in the middle. Upon release, they all swing with great force towards her — and she must pierce only the buckets with knife and fork, as she's wearing an iron corset that hurts her badly if she resumes male form. This technique is designed to hone the speed and precision of her Amaguriken technique. Note that she devised this training method herself, which probably makes her at least as crazy as Cologne (Bakusai Tenketsu, Kachu Tenshin Amaguriken) and Genma (Neko-ken.)
The series actually does treat these with a mild dose of realism, which can often go unnoticed. With the exception of the Neko-ken (and, frankly, the fact that the method of "training" didn't set alarm bells ringing in Genma's head proves what a Sink-or-Swim Mentor he is), all of these training regimes were undertaken with supervision, so the trainee had someone to jump in and pull them to safety if things got out of hand. Cologne was watching Ryoga while he trained in the Bakusai Tenketsu, Soun and Genma were with Ranma when s/he learned the Parley du Foi Gras, and Ranma underwent the normal Amaguriken training in the Tendo's garden, where people could keep an eye on him/her.
Parodied in the series itself in "The Date Monster of Watermelon Island". Kuno seemingly turns the Smashing Watermelons game into Training From Hell, giving himself Identity Amnesia when he hits one melon at just the right angle to smash it onto his head and knock himself out cold. However, it turns out that, once his amnesia is cured (and his delusions are restored) the training is nearly useless in combat; it conditions the trainee to attack watermelons with extra strength, so it's only dangerous to others if there's a watermelon around to "power up" the trainee. However, Kuno reveals it isn't intended for combat, and that he knew it was useless in that regard all along: Kuno went through the training because he wanted to improve his skills at slicing watermelons in order to impress girls.
Also, when Ukyo is first explaining all that Ranma & Genma did to her (without actually saying she is a she (because obviously she doesn't know that Ranma doesn't know), she says she had practiced her cooking against the raging sea. One student standing there asks "Why against the ocean? Isn't that kinda pointless?" to which another one replies "That's the whole point! Don't you watch samurai movies?".
Ranma's training for the Hiryuu Shoten Ha, due to its psychological component, required him to provoke Ryoga into being angry enough to kill him. Which normally is a bad idea.
Ryoga was always trying to kill him. Attacking when Ranma sleeping (worst showing). Trying to kill him with one touch after the breaking point training. Trying to kill him throwing sharpened handban d(by ki) and using one as a weapon (also by ki). Manga Ryoga is seriously not a threat to him in a fight most of the time, ignored by Ranma half the time while talking to Akane. Anime Ryoga on the other hand is far closer (also debatably more talented) to Anime Ranma, and probably can beat him in a fair fight.
The titular freedom-fighting gunslinging warriors of Samurai Gun undergo this when they are recruited into the "project" as children. In many cases, they were first traumatized by having family members brutally killed in front of them by a secret agent of the mysterious Council they take orders from, a man named Rekkai. Even if they weren't, they were then subjected to deadly training exercises that included repeated poisonings (to build immunity), electric shocks and live ammo courses. The anime states that failure in any one of these exercises resulted in the death of the failing trainee.
Seto Kaiba's Back Story in Yu-Gi-Oh!. In order to make him a suitable heir to Kaibacorp, his adoptive father Gozaburo put him through a brutally intense period of schooling from age 10 onward. Judging from what is shown in the manga, it involved leashing him to a desk and the occasional beating with a switch.
That's actually very accurate. Gozaburo tried hard to hammer it into Seto that he had to be ruthless and see everyone as a potential enemy, including him if need be. Seto may have hated the man, but he learned the lesson only too well; he eventually took over Kaiba Corp and kicked him out, then dismantled it and started from scratch, doing his best to destroy Gozaburo's legacy permanently.
Jan Akiyama of Iron Wok Jan was brutally trained since childhood by his grandfather to become a Chinese-cuisine chef. For example, basic training included flipping a wok full of stones, one handed, thousands of times in a row — and if he slowed down at all, he'd be beaten until his back was bloody. Later on in the series, the audience discovers that one of Jan's opponents in a cooking competition had undergone the same training — in the rain, while balancing barefoot on the blade of a giant sword.
Sara from Soukou No Strain dedicates herself to her training in the portion of the series where she is a Gambee pilot.
Glass Mask (Garasu no Kamen) contains a few examples from the field of stage acting. I.e.: Previous to playing the role of the blind and deaf Helen Keller, Maya spends several days blindfolded.
Subverted and parodied, like virtually everything else, in Excel♥Saga, when Nabeshin trains Excel how to bowl in a bathroom.
It was over so quickly Excel's not even sure if she underwent the promised training.
Many of the cast of YuYu Hakusho (especially Yusuke) go through this at one point or another. A sample of Genkai's training regime includes sleeping with a pitful of poisonous snakes, meditating on a bonfire for a week and defending yourself correctly against a near-fatal energy blast until you get it right.
Kurama puts some of his former Dark Tournament rivals through this (Genkai's training regime) in order to get six fighters with 100,000 demon power or more to satisfy Yomi.
"How did you get them to be so powerful in such a short time?"
Genkai: "Oh, just moderate exercise and healthy food."
Trainees: "That hell training and horrible medicines is considered moderate exercise and healthy food?!!"
In Fullmetal Alchemist, Izumi Curtis has put Alphonse and Edward through quite a bit of Training from Hell, to the point that they're genuinely terrified of her. The manga's volume 6 even includes a part where she states she has "Training from hell plan B" scheduled for the afternoon, and therefore should cook a lunch high in calories. (This is from the Viz media release, while other translators' exact phrasing may be different, it'll probably include the 'training' and 'hell' bits.)
Izumi herself went through training from hell herself. She was left for one month with no supplies in the middle of a perpetual blizzard. She had to fight bears bare-handed.
What makes it funny is how Olivier tells the Elrics that once, a strange woman broke into Briggs and stole food and supplies for a whole month.
Turns out it was all a misunderstanding, and the guy who gave her the assignment was the martial arts master, not his (dead) brother the alchemist. Hilarity Ensues.
However ironically, it still gave her valuable lessons in Alchemy.
In One Piece, Vice-Admiral Garp took Coby and Helmeppo under his wing, teaching two previously pathetic characters Charles Atlas Superpowers, as well as the confidence to use them. Much of his training seems to involve hitting them a lot and yelling at them, with the intent of getting them to snap and fight back against him. As a result, they are able to put in a good showing (though not beat) his grandson Luffy, who he also raised with such brutal training.
Like Rock Lee, Zoro trains with almost absurdly heavy weights for almost impossibly long durations.
"Almost" absurdly? To practice swinging his sword, he uses one half of a dumbbell with weights almost as big as he is! (And almost assuredly many times heavier)
One Piece also subverts this trope, though, in that almost all the training happens offscreen. The Straw Hats always seem to come up with cool new attacks at the start of new storylines, mainly because it's implied that they put themselves through rigorous training during the long stretches of otherwise uneventful sailing between islands. This is supposedly because Oda dislikes training arcs. The only Straw Hat we ever actually see training is Zoro, mainly because he never seems to do anything except eat, train, and sleep.
All the main crew went through some training during the Time Skip to better themselves at their jobs, all with varying degrees of hellishness.
Luffy: Was put on an island full of the most terrifying beasts known to man where everything was out to kill him all while Silvers Rayleigh was forcing him to learn Haki.
Zoro: Trained under the Warlord of the Sea Dracule Mihawk, after being able to defeat all of the war-loving gorillas already residing on that island. Not yet explained, but he ended up losing an eye during this training.
Nami: Learned "knots" and Weather Balls on the Sky Island Weatheria to better her navigation skills under the training of the Weather Wizards. Looks to have further improved her Clima-Tact.
Usopp: Landed on an island full of man-eating plants which trick giant Sea Kings and other monsters to them. Learned about "Pop Greens" under the guidance of Heracles, the ultimate survivalist. Also beefed up physically.
Sanji: Landed in an Ironic Hell full of transvestites ruled by Emporio Ivankov. He learned "attack cooking" that will supply nutritional boosts to the crew, while having to fight all the okama fighters of the island to get the recipes.
Chopper: Studied the ancient technology and medicines of an island that was locked in war with the giant hawks.
Robin: Trained under Dragon the Revolutionary and his organization after spending some time as a prisoner/slave.
Franky: Researched in Dr. Vegapunk's old lab, and managed to rebuild himself into a bigger, tougher cyborg with tons of features.
Brook: Fought the "long arms," who then kidnapped him to be an exhibit. During that time he attained world-wide fame as "Soul King" Brook as he traveled the world doing concerts to improve his music. Also learned to astrally project his own soul.
Allen Walker in D Grayman underwent this under General Cross, who — aside from making Allen fight and practical things like that — also tended to drop his debts on the boy, among other things. For a while, every time anyone mentions the general around Allen, he goes catatonic at the mere memory.
As a side-effect, he now has insanely awesome poker cheating skills, as well as a scary evil side that pops up whenever cards are around. * shiver*
Doing sit-ups while hanging from a bar, and a fire underneath which would burn him if he'd stop.
Jumping off a 100m high cliff. (He is given an option. He could either take the jump and relax on vacation, or spend two days training. He picks the jump.)
Just getting smacked around.
Akisame's various torture machines that get more violent and dangerous as they go along.
Being locked in a cave, with no light or food, filled with traps for days. When Kenichi comes out, an old opponent is waiting to fight him. Kenichi ignores him.
The very first thing they made him do was horse stance over a fire, holding fifty pound weights in his outstretched arms, with blades attached to his inner arms that will stab him if he lets them down. When he needs a break, Akisame attaches a rope to a tire, sits on it, and tells him to drag it to the store.
Kenichi: But that's three stops away! Do you expect me to walk there?
Akisame: No, no, of course not. I expect you to run.
It's even worse in the manga; where it's humorously implied that he occasionally dies and has to be brought back with Kensei Ma's potions.
When Kenichi was forced to jump off the cliff into the ocean, he didn't even know how to swim, and the masters still pushed him in anyway.
Akisame: "So you can't swim? That's no excuse!"
Sakaki: "It just makes things more exciting!"
A humorous aversion occurs in the manga. When Ryozanpaku needs money badly, Miu has some of the masters take up teaching young children for a little while for the income. Kenichi initially freaks at the idea, fearing his masters will give these kids the same training he gets. However, despite some initial difficulty for Sakaki and Shigure trying to give out actual kunai, the masters train them quite normally.
When his former-opponent-turned-friend Takeda the Puncher eventually finds himself a good boxing master to catch up with Kenichi, the said master (James Shiba) gives him a Training from Hell as well. When doing the (now already) usual training routine of Kenichi running through the park towing his master Akisame, they encounter Shiba and Takeda doing a similar training routine. Then Hilarity Ensues as the two masters (who are personally friendly rivals) compete who of them will make his disciple run faster.
The first story arc of JoJo's Bizarre Adventure mentions "the Seventy-Seven Rings", an ancient training challenge for knights. It involves climbing a giant mountain in heavy armor, defeating seventy-seven opponents along the way. When you defeat one, you must don an iron ring that they were wearing. By the seventy-seventh, those rings equal about 300 extra pounds of weight. Only five men ever completed it. Two of them battle Jonathan at once.
The second part gives us the Pillar of Hell, which both Joseph and Caesar are forced to do at the beginning of their training. They're tossed into a twenty-four-meter-deep pit, the only way out of which is to climb a stone pillar. The pillar continually coats itself with vegetable oil, and any attempts to improvise a rope are prevented by the pillar shooting out a knife and cutting it. The only way out is to use the Ripple to cling to the pillar and claw your way up. To add insult to injury, there's a crack partway up to trick people into trying to rest by using it as a handhold... but it's actually a switch that causes a massive field of high-pressure oil to spray out near the top, making things even harder. And Joseph has to climb it wearing a mask that suffocates him unless he can keep up the proper breathing rhythm. And this is the first step to the training.
Yoh of Shaman King has to go through this for his entire summer vacation. And he's put through it by his fiancee. Just judging by what we see in a montage panel, Anna's "special training course" includes slapping and scratching Yoh if he screws up, forcing him to climb a smooth tree and hold his position (lest he fall into a pile of crap), chasing him on a bike with a poleaxe, and forcing him to do homework. During Summer Break.
Later on, Yoh, Ren, Chocolove, and Horo Horo go through training from hell LITERALLY
In Samurai Girl: Real Bout High School, Megumi Momoi puts herself through Training from Hell, using a pitching machine. No, she wasn't dodging the balls, she was letting them hit her so she'd be able to take hits from her opponent at Dragon Land (who she would be facing the next day).
To be qualified enough to compete with the most seasoned performers in the Kaleido Stage, Sora Naegino from Kaleido Star is just too often subjected to several variants of this. And she's not the only one: Layla Hamilton, Sophie and Leon Oswald, Mia Guillem, Anna Heart, May Wong and Rosetta Passel and others also have to go through it. In the first season, Layla almost develops an eating disorder and injures her shoulder very seriously during her and Sora's training for the Amazing Maneuver that would let them take the Stage back from Yuri Killian...
Cornet puts Flute through this kind of training in Violinist of Hameln, ostensibly in order to teach her magic. The training includes doing 5000 squats, walking across a tightrope with a weight on her back (which breaks the rope) and getting pelted with baseballs. Of course, Cornet's just trying to get rid of Flute so she can get together with Hamel.
In Mahou Sensei Negima!, a lot of Evangeline's training techniques are like this. A notable one consisted of her effectively dumping Asuna in the middle of the Himalayas, with nothing but the clothes on her back. If she doesn't die or give up for a week, she passes. It's also said that Negi and Kotaro went through it at one point too.
This was the admissions test, and Asuna making it through meant that Evangeline would actually start bothering to train her for real. Worse, originally Evangeline intended for Asuna to do it naked, with no available shelter, and with no source of food (Negi and Kotaro had just been there and had left some behind). But she likes Asuna (or would if Asuna didn't want training), and decided to go easy on her.
Even Eva's "normal" training is terrible, such as making Negi fight herself, Chachamaru, and Chachazero simultaneously. He passes if he can survive for a minute. Keep in mind that at the point the training began, any one of them could have kicked Negi's ass with no trouble. Especially Eva, who's one of the most powerful beings alive, to the point that she actually forced the Big Bad to retreat just by being present. The fact that she sucks Negi's blood as "payment" for the training doesn't make it any easier.
Judging by Asuna's words, Negi trains himself dangerously past the brink of exhaustion a lot, and possibly has been doing so since he was four.
It's also parodied by Ku Fei, who attempts to teach Negi martial arts this way and fails miserably, because she took all of her methods from movies and manga.
In chapter 285 Training from Hell takes new meaning when it involves Negi actually turning into a demon.
Every single Saint in Saint Seiya endured hellish training to earn his or her Sacred Cloth — doing finger-stands (as in, standing on the tip of your index finger) during rain and snow, punching glaciers or mountains thousands of years old and not giving up until they crumbled, doing upside-down pullups while hanging from your feet above a chasm, being chained between two rocks and being forced to push back the ocean tide with your Battle Aura before you drown, that sort of thing. And even then, the characters that endured these trials gasp in horror at the one who came back from Death Queen Island, considered the worst ordeal of them all.
Parodied in Mr Fullswing, where Sawamatsu trains Amakuni for the baseball team tryouts. He proves extremely Genre Savvy; "When you talk about baseball manga, it's all about the river scene..." Except once they get there, Sawamatsu just wants Amakuni to readd a rulebook. When Amakuni complains, he grudgingly decides that they could do some "sports manga-ish training" instead. So, naturally, Sawamatsu starts mean-spiritedly smacking him around with the bat and hitting balls directly into his face. Throughout the rest of the week, he put Amakuni through a brutal regimen of training that he knew he wouldn't be able to keep up with, just for fun. And, while both of the initial stages of the training were subversions, he eventually plays it straight by making Amakuni field by the riverside; Since it's covered with rocks, he'd only get irregular bounces, and if he could field there, he could field anywhere.
And note that unlike a lot of these, Sawamatsu makes Amakuni work on something he actually isn't good at, fielding, because he's already a master at bat. And whatever improvement Amakuni experienced in that regard wasn't very impressive.
Baki Hanma's entire life is essentially Training from Hell, initiated by his mother so that he could someday defeat his father. He's almost there, and seems to be glad, as he apparently has gotten a little tired of it.
His older brother Jack takes it Up to Eleven, to the point where he has to take super steroids just so his body can keep up with his unreasonable training. The scientist who gave him the steroids found him in a gym where he was hitting a punching bag for twelve hours straight.
By extension every fighter of note in the series has went through training that would make super athletes weep. Some examples are: using an helicopter for ab work outs, punching a huge stone until it is a sphere, and landscaping.
Kirika and Chloe of Noir both went through this, being trained from near-infancy by Altena to be the perfect assassins. Both girls' training involved copious amounts of Mind Rape and Break the Cutie as well, the better to render them into utterly emotionless killers. Mireille managed to deprogram Kirika; Chloe simply went Ax-Crazy.
Biscuit's Kruger training from Hunter × Hunter. Also Killua's heavy endurance is due to his family's very harsh assassin training straight from birth.
Played as straight as can be in Chirin No Suzu. Chirin trains under the Big Bad and goes from dainty little white cartoon sheep to black murderous hell ram after two years of training. The wolf even tells Chirin that his life will be hell from then on out. Interestingly enough, things don't end well for him either.
Seiji "Mad Dog" Sawamura in Midori no Hibi was a nice, peaceful child, and picked on for it...until Cool Big Sis Rin forced him through this with sadistic glee, forging him into an unstoppable fighter...with a fear of dogs. Being chased, with meat tied to you, does that... She also used fire, and sees to have tried hypnosis. Partially subverted, as his first fight, after a week of training, he lost', though he never gave up the fight, and no one was able to beat him since then. Save for Rin.
Although a subversion (?) because where you'd expect a Hot Blooded Idiot Hero such as him to succeed by putting himself through endless fights and one thorough Curb Stomping, Black Star's turning point is not a fight but a conversation with the Nakatsukasa spirit inside Tsubaki.
Chinmi of Tekken Chinmi (aka Ironfist Chinmi) does this with nearly every issue. One scene that stands out: when captured by the enemy and told he'll be executed at dawn, he spends the night training a particular move in the hopes it will save his life. By the end, he's accomplishing handstands with his forefingers.
Paul did this to Chimchar — and most of his Pokémon — in the Diamond and Pearl series of the Pokémon anime. This is presented as a very bad thing, just like everything else Paul does when it comes to raising Pokémon.
Ash's Charmander was put through this by its former trainer Damien...by leaving it out in a rainstorm. Did we mention the Char evolution line die if their tail flame goes out? Brock, and pretty much everyone else, was pissed when he found out.
A trainer from the first season named AJ put all his Pokemon through rather harsh training which included retraining devices, which did get Ash and company worked up. However, unlike Paul, AJ treated his Pokemon rather well when he wasn't training them and was proud of them.
Most of the cast from Katekyo Hitman Reborn! are put through some form of hellish training during the course of the series, but Tsuna, main character and future Mafia boss, definitely wins first place. Some of the more memorable trials he has suffered at the hands of his tutor Reborn include being set on fire, repeatedly shot at with heavy artillery, thrown off a cliff with a whirlpool beneath it, made to stand one-legged on a rock in the middle of a mine field, beaten to within an inch of his life on a daily basis, and habitually taking a bullet to the head. Though it does eventually pay off, you can't help but feel sorry for the kid...
Motoko Gettou from Change 123 does this from when she was five. When her mother died, three "fathers" (in truth only her mother's acquaintances) came to pick her up: one was a karate master who killed a tiger with his bare hands; one is a master swordsman, tactician and firearms expert; and one is a grand master of jujitsu. Naturally, they taught her everything they know.
With the little side effect of making her develop three split personalities, one for each of her fathers' specialty, to cope with the training and a Super-Powered Evil Side that nearly killed two out of three fathers in the three minutes before passing out. She was 11 at that time.
Parodied in Kamen no Maid Guy, when Kogarashi trains Naeka for an upcoming high school Kendo tournament. Some of his training methods include having her fight a bear, and dropping a log on her from on top of a waterfall. She fails most of the more ridiculous exercises, but Kogarashi gives her a pass anyway for her effort
Years before The Bride took up Training from Hell from Pai Mei, the title character of Lady Snowblood, Oyuki, prepared for her Roaring Rampage of Revenge against her mother's rapists by undergoing Training from Hell as an assassin from a priest.
Takeda Shingen from Sengoku Basara holds "Hot-Blooded Manly Training Festivals" which basically involve his soldiers beating each other to a pulp until he is satisfied with their progress. His idea of being a mentor also seems to be making his ward Yukimura stronger by punching him through walls on a daily basis.
Kamina briefly adopts this in Tengen Toppa Gurren Lagann when he attempt to teach Simon to combine in a more awesome fashion...by throwing 40-ton boulders at him. Without giving Simon time to get into Lagann. Fortunately for everyone concerned, this was an isolated incident.
In Märchen Awakens Romance, Ginta, Jack, Snow and Dorothy get trapped in the Gate of Training for 180 days. Ginta spends about twelve hours trying to break but not destroy a wall by synchronizing with his arm. And Jack and Dorothy's Guardian ARM is an ugly, cranky cat lady who hates Jack. And just being stuck in another dimension with Jack is hell for Dorothy. We don't get to see much of the training after that, but in one montage, Ginta does appear to be coughing up blood, and he comes out with a scar on his face, so something that the viewer didn't see also had to happen that would qualify this as Training From Hell. So Yeah.
Ginta and Jack actually go through this TWICE- Gaira puts them through more unseen Training From Hell, they come back tired and beaten up with their reflexes increased. Since we didn't actually see what happened, I'm not sure if this counts.
In Gokusen, a business CEO offers the students "masculinity training." It's a series of grueling physical tasks (and such "masculine" tasks as drinking), with each successive training series guaranteeing a minimum wash-out, and making cheating not only easily possible, but not punishing it even when the proctors see it. Of course, it's all part of a Secret Test of Character — those who both pass AND refuse to cheat do better than those who pass and cheat; those who pass and help others do even better.
Rurouni Kenshin: Kenshin's daily training consisted of getting the snot beaten out of him by an adult easily twice his size, first by Technique A until he figured out how to use it, then Technique B (which happens to be the perfect counter for A) until he figured that out and so forth.
Given three days to get Leina from "novice" to "ready to fight Risty", Echidna decides to do so by coating both of them with a sap that prevents injury... and then spending those three days actively attempting to kill Leina. Die or Fly at its best.
In Slayers, protagonist Lina Inverse puts Amelia through this kind of hellish training (including pulling a huge cart of groceries for Lina to eat). Subverted in that Lina wasn't really trying to teach Amelia anything, she was just putting the other girl through the most brutal regimen she could think of in the hopes of making her give up and go away.
In episode 14 Konoe takes Taro into the mountains and puts him through training worthy of a martial arts movie. Running, standing under a waterfall, etc.
Episode 5. Ryuuka joins the household as a maid and takes over the division that serves Taro personally, putting them through a harsh workout.
Episode 6. Most of the maid departments go through vigorous physical training to prepare for a softball tournament.
Fitting for a man who can fight hand to hand with dinosaurs, Ryoma of Getter Robo had a father who trained him since early childhood in the harsh art of karate until his hands "swelled so badly they looked like they had gloves on them." This included making him fight dogs, as seen here.
In chapter 358 of Hayate the Combat Butler, Ruka needs to learn how to ride a bike in four hours. Hayate offers her a choice between kind lessons and harsh lessons. She chooses harsh, so he gives her the same training he gave himself.
Hayate: Don't worry. People can do anything when they think they're going to die.
Ruka: I really will die before that happens!
Kaleido Star is full of this. Examples: Training for the Legendary Great Maneuver destroyed Layla's shoulder and drove Sora to an emotional breakdown. Training for the Angel's Maneuver required Sora to stand on a floating log one-legged and lower then lift her whole body weight without causing the water to ripple at all — 100 times! Another part of the training ripped all of the skin from her toes.
Leon and his sister, Sophie, were subjected to hellish training when they were younger. Examples: standing in the same position for hours, juggling lead balls, sitting at a table without a chair (assuming the sitting position using leg strength alone).
In the World of Badass that is Medaka Box this is undergone at least once an arc since the Genre Shift. The brightest example being the first; Kurokami Medaka's older brother Maguro's special power is being able to bring out the best in anyone he trains, for Zenkichi and Medaka he developes two training regimes, one being a course where they would go to sleep and wake up even stronger, the other is explicitly this and the results aren't even guaranteed. The next episode/chapter features Medaka's and Zenkichi's clothes being tattered to shreds, but the two put up a good showing against Arc Big Bad Miyakonojou Oudo and soundly beating his Quirky Mini Boss Squad to the point of friendship.