Hysterical strength, or superhuman strength, is a display of extreme strength by humans, beyond what is believed to be normal, usually occurring when people are in life and death situations. Common anecdotal examples are of mothers lifting vehicles to rescue their children. The extra strength is believed to come from adrenalin, though incidents are rare, unrepeatable, with no examinable evidence and few witnesses; research into the phenomenon is difficult, though it is thought that it is theoretically possible.
The most common anecdotal examples are of mothers lifting vehicles to rescue their children, and when people are in life and death situations. Hysterical strength can result in torn muscles due to higher mechanical stress.
- In 1982, in Lawrenceville, Georgia, Tony Cavallo was repairing a 1964 Chevrolet Impala automobile from underneath. The vehicle was propped up with jacks, but it fell. Cavallo's mother, Mrs. Angela Cavallo, lifted the car high enough and long enough for two neighbours to replace the jacks and pull Tony from beneath the car.
- In 2006, Ivujivik, Quebec resident Lydia Angiyou saved several children by fighting a polar bear until a local hunter shot it.
- In 2006, in Tucson, Arizona, Tom Boyle watched as a Chevrolet Camaro hit 18-year-old Kyle Holtrust. The car pinned Holtrust, still alive, underneath. Boyle lifted the Camaro off the teenager, while the driver of the car pulled the teen to safety.
- In 2009, in Ottawa, Kansas, 5 ft 7 in (1.70 m), 185 lb (84 kg) Nick Harris lifted a Mercury sedan to help a 6-year-old girl pinned beneath.
- In 2011, in Tampa, Florida, 6 ft 3 in (1.91 m), 295 lb (134 kg) college football player Danous Estenor lifted a 3,500 lb (1,600 kg) car off of a man who had been caught underneath. The man was a tow truck driver who had been pinned under the rear tire of a 1990 Cadillac Seville, which had lurched forward as he worked underneath it. The man suffered only minor injuries.
- In 2012, in Glen Allen, Virginia, 22-year-old Lauren Kornacki rescued her father, Alec Kornacki, after the jack used to prop up his BMW slipped, pinning him under it. Lauren lifted the car, then performed CPR on her father and saved his life. 
- In 2013, in Oregon, teenage sisters, Hanna (age 16) & Haylee (age 14) lifted a tractor to save their father pinned underneath. 
Amphetamine and other stimulants are used by some athletes for their psychological and performance-enhancing effects. In competitive sports, this form of use is prohibited by anti-doping regulations. In healthy people at oral therapeutic doses, amphetamine has been shown to increase physical strength, acceleration, stamina, and endurance, while reducing reaction time. Like methylphenidate and bupropion, amphetamine increases stamina and endurance in humans primarily through reuptake inhibition and effluxion of dopamine in the central nervous system.
Superhuman strength is an ability commonly employed in fiction. It is the ability for a character to be stronger, tougher, more durable, and more physically powerful than humanly possible. Characters and deities with super strength have been found in many ancient mythologies and religions. Superhuman strength is a common feature across a wide range of media, such as novels, comic books, television, films, and video games.
Discovery channel produced a show called "Superhuman Showdown", one of the main classification was superhuman strength, in which five finalist were selected in the following category: Jimmy Bandera for his high-frequency voice, Dr. MAK Yuree for his leg power, Conard for his abdominal strength, Frannz Muellner for his arm strength and Jamal for his lung power.
Superhuman strength is used by several characters in fantasy and science fiction, with a variety of proposed mechanisms such as cyborg body parts or genetic modification and even telekinetic fields in science fiction, or divine or magical/supernatural sources in fantasy. A plethora of comic book superheroes and supervillains usually have a degree of super strength. The level of strength portrayed can vary greatly, from just outside the "normal" human range of the strongest weightlifters of a given size or muscle mass (e.g. unarmored Master Chief), to nearly or even unlimited (e.g. Hulk, Superman, Supergirl, Superwoman, Thor, Hercules and Goku).
- Ransom Riggs (25 March 2011). "Does Hysterical Strength Really Exist?". mentalfloss.com.
- "White Paper Report on Excited Delirium Syndrome", ACEP Excited Delirium Task Force, American College of Emergency Physicians, September 10, 2009
- Sztajnkrycer, Matthew D.; Baez, Amado A. "Cocaine, Excited Delirium and Sudden Unexpected Death" (PDF). Retrieved 29 November 2012.
- Clark, Josh. "How can adrenaline help you lift a 3,500-pound car?", 11 December 2007. HowStuffWorks.com. retrieved 13 November 2008.
- Jane George (2006-02-17). "Polar bear no match for fearsome mother in Ivujivik". Nunatsiaq News / Nortext Publishing Corporation (Iqaluit). Retrieved 2009-01-01.
- Huicochea, Alexis. "Man lifts car off pinned cyclist", Arizona Daily Star, 28 July 2006. retrieved 21 November 2010.
- Associated Press. "Kansas dad somehow lifts car off 6-year-old girl", 18 December 2009. news.yahoo.com. retrieved 19 December 2009.
- Greg Auman (2011-06-24). "USF Bulls offensive lineman Danous Estenor lifts car to free trapped man". St. Petersburg Times (Tampa Bay, FL).
- Hoh, JF; Rossmanith, GH; Kwan, LJ; Hamilton, AM (1988). "Adrenaline increases the rate of cycling of crossbridges in rat cardiac muscle as measured by pseudo-random binary noise-modulated perturbation analysis". Circulation Research 62: 452–461. doi:10.1161/01.RES.62.3.452.
- Liddle DG, Connor DJ (June 2013). "Nutritional supplements and ergogenic AIDS". Prim. Care 40 (2): 487–505. doi:10.1016/j.pop.2013.02.009. PMID 23668655. "Amphetamines and caffeine are stimulants that increase alertness, improve focus, decrease reaction time, and delay fatigue, allowing for an increased intensity and duration of training ...
Physiologic and performance effects
• Amphetamines increase dopamine/norepinephrine release and inhibit their reuptake, leading to central nervous system (CNS) stimulation
• Amphetamines seem to enhance athletic performance in anaerobic conditions 39 40
• Improved reaction time
• Increased muscle strength and delayed muscle fatigue
• Increased acceleration
• Increased alertness and attention to task"
- Bracken NM (January 2012). "National Study of Substance Use Trends Among NCAA College Student-Athletes". NCAA Publications. National Collegiate Athletic Association. Retrieved 8 October 2013.
- Parr JW (July 2011). "Attention-deficit hyperactivity disorder and the athlete: new advances and understanding". Clin Sports Med 30 (3): 591–610. doi:10.1016/j.csm.2011.03.007. PMID 21658550.
- Roelands B, de Koning J, Foster C, Hettinga F, Meeusen R (May 2013). "Neurophysiological determinants of theoretical concepts and mechanisms involved in pacing". Sports Med. 43 (5): 301–311. doi:10.1007/s40279-013-0030-4. PMID 23456493.