Alpha (α) motor neurons (also called alpha motoneurons), are large, multipolar lower motor neurons of the brainstem and spinal cord.
 They innervate extrafusal muscle fibers of skeletal muscle and are directly responsible for initiating their contraction.
 Alpha motor neurons are distinct from gamma motor neurons, which innervate intrafusal muscle fibers of muscle spindles.
Muscle contraction is the activation of tension-generating sites within muscle fibers.
 In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length such as holding a heavy book or a dumbbell at the same position.
 The termination of muscle contraction is followed by muscle relaxation, which is a return of the muscle fibers to their low tension-generating state.
Rolf Nidergerke (30 April 1921 – 27 December 2011) was a German physiologist and physician, and one of the discoverers of the sliding filament theory of muscle contraction.
 He and Andrew Huxley, complimenting the independent works of Hugh Huxley and Jean Hanson, revealed that muscle contraction is due to shortening of the muscle fibres.
 He studied medicine throughout the Second World War, and obtained his MD degree as the war ended in 1945.
 After a brief practise in his hometown, he chose a research career.
 He became associated with Huxley, whom he joined at Cambridge University.
 Together they published a landmark paper in "Nature" in 1954, which became the foundation of muscle mechanics.
A tetanic contraction (also called tetanized state, tetanus, or physiologic tetanus, the latter to differentiate from the disease called tetanus) is a sustained muscle contraction evoked when the motor nerve that innervates a skeletal muscle emits action potentials at a very high rate.
 During this state, a motor unit has been maximally stimulated by its motor neuron and remains that way for some time.
 This occurs when a muscle's motor unit is stimulated by multiple impulses at a sufficiently high frequency.
 Each stimulus causes a twitch.
 If stimuli are delivered slowly enough, the tension in the muscle will relax between successive twitches.
 If stimuli are delivered at high frequency, the twitches will overlap, resulting in tetanic contraction.
 A tetanic contraction can be either unfused (incomplete) or fused (complete).
 An unfused tetanus is when the muscle fibers do not completely relax before the next stimulus because they are being stimulated at a fast rate; however there is a partial relaxation of the muscle fibers between the twitches.
 Fused tetanus is when there is no relaxation of the muscle fibers between stimuli and it occurs during a high rate of stimulation.
 A fused tetanic contraction is the strongest single-unit twitch in contraction.
 When tetanized, the contracting tension in the muscle remains constant in a steady state.
 This is the maximal possible contraction.
 During tetanic contractions, muscles can shorten, lengthen or remain constant length.
A gamma motor neuron (γ motor neuron), also called gamma motoneuron, is a type of lower motor neuron that takes part in the process of muscle contraction, and represents about 30% of fibers going to the muscle.
 Like alpha motor neurons, their cell bodies are located in the anterior grey column of the spinal cord.
 They receive input from the reticular formation of the pons in the brainstem.
 Their axons are smaller than those of the alpha motor neurons, with a diameter of only 5 μm.
 Unlike the alpha motor neurons, gamma motor neurons do not directly adjust the lengthening or shortening of muscles.
 However, their role is important in keeping muscle spindles taut, thereby allowing the continued firing of alpha neurons, leading to muscle contraction.
 These neurons also play a role in adjusting the sensitivity of muscle spindles.
The sliding filament theory explains the mechanism of muscle contraction based on muscle proteins that slide past each other to generate movement.
 It was independently introduced in 1954 by two research teams, one consisting of Andrew F. Huxley and Rolf Niedergerke from the University of Cambridge, and the other consisting of Hugh Huxley and Jean Hanson from the Massachusetts Institute of Technology.
 It was originally conceived by Hugh Huxley in 1953.
 Andrew Huxley and Niedergerke introduced it as a "very attractive" hypothesis.
Sir Andrew Fielding Huxley {'1': ", '2': ", '3': ", '4': "} (22 November 191730 May 2012) was a Nobel Prize-winning English physiologist and biophysicist.
 He was born into the prominent Huxley family.
 After graduating from Westminster School in Central London, from where he won a scholarship to Trinity College, Cambridge, he joined Alan Lloyd Hodgkin to study nerve impulses.
 Their eventual discovery of the basis for propagation of nerve impulses (called an action potential) earned them the Nobel Prize in Physiology or Medicine in 1963.
 They made their discovery from the giant axon of the Atlantic squid.
 Soon after the outbreak of the Second World War, Huxley was recruited by the British Anti-Aircraft Command and later transferred to the Admiralty.
 After the war he resumed research at The University of Cambridge, where he developed interference microscopy that would be suitable for studying muscle fibres.
A myocyte (also known as a muscle cell) is the type of cell found in muscle tissue.
 Myocytes are long, tubular cells that develop from myoblasts to form muscles in a process known as myogenesis.
 There are various specialized forms of myocytes: cardiac, skeletal, and smooth muscle cells, with various properties.
 The striated cells of cardiac and skeletal muscles are referred to as muscle fibers.
 Cardiomyocytes are the muscle fibres that form the chambers of the heart, and have a single central nucleus.
 Skeletal muscle fibers help support and move the body and tend to have peripheral nuclei.
 Smooth muscle cells control involuntary movements such as the peristalsis contractions in the oesophagus and stomach.
A fasciculation , or muscle twitch, is a small, local, involuntary muscle contraction and relaxation which may be visible under the skin.
 Deeper areas can be detected by electromyography (EMG) testing, though they can happen in any skeletal muscle in the body.
 Fasciculations arise as a result of "spontaneous depolarization" of a lower motor neuron leading to the synchronous contraction of all the skeletal muscle fibers within a single motor unit.
 An example of normal spontaneous depolarization is the constant contractions of cardiac muscle, causing the heart to beat.
 Usually, intentional movement of the involved muscle causes fasciculations to cease immediately, but they may return once the muscle is at rest again.
Intrafusal muscle fibers are skeletal muscle fibers that serve as specialized sensory organs (proprioceptors) that detect the amount and rate of change in length of a muscle.
 They constitute the muscle spindle and are innervated by two axons, one sensory and one motor.
 Intrafusal muscle fibers are walled off from the rest of the muscle by a collagen sheath.
 This sheath has a spindle or "fusiform" shape, hence the name "intrafusal".

Question: What is the name of this Nobel Prize-winning English physiologist and biophysicist, who was born in Nobember 1917 and who, along with Rolf Niedergerke, revealed that muscle contraction is due to shortening of the muscle fibers?
Answer: Andrew Huxley