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 include parents lifting vehicles to rescue their children. Such examples, however, have not been proven and have been dismissed by doctors across the world. The extra strength is believed to come from adrenaline, though incidents are rare and never proven as there were no examinable evidence or witnesses; research into the phenomenon is difficult, though it is thought that it is theoretically possible.
The most common anecdotal examples are of parents 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; 13.2 st) 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; 21.1 st) University of South Florida 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.
- In 2015, in St. John's, Newfoundland, Nick Williams lifted a four-wheel-drive vehicle to save a young boy pinned beneath its tire.
- In 2015, in Vienna, Virginia, Charlotte Heffelmire was able to momentarily use incredible strength to free her dad from a GMC pick-up truck. 
Early experiments showed that adrenaline increases twitch, but not tetanic force and rate of force development in muscles. It is questionable, however, as to whether adrenaline, released from the adrenal medulla into the venous circulation, can reach the muscle quickly enough in order to be able to cause such an effect in the midst of a crisis. It may be that noradrenaline released from sympathetic nerve terminals directly innervating skeletal muscle, has more of an effect over the timescale of seconds.
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 release of dopamine in the central nervous system.
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- Associated Press. "Kansas dad somehow lifts car off 6-year-old girl", 18 December 2009. news.yahoo.com. Retrieved 19 December 2009.
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- "Shea Heights hero finds strength to lift vehicle off injured boy". CBC News. 28 September 2015. Retrieved 28 September 2015.
- McCrum, Kirstie (11 January 2016). "Teen girl uses 'superhuman strength' to lift burning truck off dad and save family". Mirror. Retrieved 11 January 2016.
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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
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