protection, such as when the joint receptors are signaling joint hyperextension or hyperflexion. Autogenic inhibition refers to a reduction in excitability of a contracting or stretched muscle, that in the past has been solely attributed to the increased inhibitory input arising from Golgi tendon organs (GTOs) within the same muscle. It was first thought GTOs only had protective function which was to prevent muscles from damages because of the assumptions that they always inhibited motoneurons and that they fired only under high tension. But it is now known that GTOs signal muscle tension continuously providing precise information about muscle force, that the reflex pathway has multisensory inputs that may allow precise control of muscle forces for fine activities, and that Ib fibers connect widely with motoneurons innervating muscles acting on different joints, which when complemented with their reflex pathways, are part of reflex networks that control movements of the whole limbs. The reduced efferent (motor) drive to the muscle by way of autogenic inhibition is a factor historically believed to assist target muscle elongation, although current literature casts doubt on this hypothesis. Protective steps With muscle tension, a Golgi tendon reflex operates as follows: As tension is applied to a tendon, the Golgi tendon organ (sensor) is stimulated (depolarized) Nerve impulses (action potentials) arise and propagate along sensory fiber Ib into the spinal cord Within the spinal cord (integrating center), sensory fiber Ib synapses with and activates (via glutamate) an inhibitory interneuron The inhibitory interneuron releases the neurotransmitter glycine that inhibits (hyperpolarizes) the α motor neuron As a consequence fewer nerve impulses are generated in the α motor neuron The muscle relaxes and excess tension is relieved Flexibilities The output of the Ib inhibitory interneurons are flexible because they receive inputs from golgi tendon organs, muscle spindles, cutaneous receptors, joint receptors, and different descending pathways. The multiple sensory/control inputs may allow fine motor activities, such as grasping a delicate object, in which other senses may guide force control. In addition, stimulating GTO doesn't always inhibit motor neurons, because during activities such as walking, the Ib inhibitory interneurons are inhibited, and Ib excitatory interneurons stimulate the motoneurons. Contrast to stretch reflex The stretch reflex operates as a feedback mechanism to control muscle length by causing muscle contraction. In contrast, the tendon reflex operates as a negative feedback mechanism to control muscle tension. Although the tendon reflex is less sensitive than the