The stretch reflex and the contributions of C David Marsden

Abstract

The stretch reflex or myotatic reflex refers to the contraction of a muscle in response to its passive stretching by increasing its contractility as long as the stretch is within physiological limits. For ages, it was thought that the stretch reflex was of short latency and it was synonymous with the tendon reflex, subserving the same spinal reflex arc. However, disparities in the status of the two reflexes in certain clinical situations led Marsden and his collaborators to carry out a series of experiments that helped to establish that the two reflexes had different pathways. That the two reflexes are dissociated has been proved by the fact that the stretch reflex and the tendon reflex, elicited by stimulation of the same muscle, have different latencies, that of the stretch reflex being considerably longer. They hypothesized that the stretch reflex had a transcortical course before it reached the spinal motor neurons for final firing. Additionally, the phenomenon of stimulus-sensitive cortical myoclonus lent further evidence to the presence of the transcortical loop where the EEG correlate preceded the EMG discharge. This concept has been worked out by later neurologists in great detail, and the general consensus is that indeed, the stretch reflex is endowed with a conspicuous transcortical component.

Maturity alters drop vertical jump landing force‐time profiles but not performance outcomes in adolescent females

“…A correlation between center of mass displacement and vertical force has previously been applied to female athletes to determine the magnitude of spring‐like behavior for the purposes of calculation of vertical stiffness in a submaximal hopping task 18 . When an athlete displays spring‐like behavior, this could be indicative of increased dampening mechanisms that effectively reduce spikes in ground reaction force during the early part of ground contact through greater preactivation and engagement of the stretch‐reflex 19,20 . This spring‐like behavior was shown to be sensitive to maturation in males, 17 but has not been assessed at different stages of maturity in female athletes.…”

Edgar adrian and patrick merton: Names blurred with the passage of time

“…However, the latency of the ankle tendon jerk was about 37 ms and that of the jaw jerk was 8 ms only. [ 13 14 ] This study almost incontrovertibly suggested that two different pathways existed for the stretch reflex and the tendon reflex, and that in the former, almost certainly a transcortical contribution operates in its genesis. In recognition of the works of the 3Ms, this pathway has been named M1, M2, and M3 long latency loop by Tatton and Lee in their subsequent works.…”

“…to suggest that there might be a stretch reflex pathway through the brain, separate from that subserving the tendon reflex, in addition to the well-known monosynaptic spinal reflex arc, and thus it was a significant addition to the classical Sherringtonian concept which assumes only spinal segmental passage for the genesis of the deep tendon reflex. [ 11 12 13 14 ] Although the precise pathway responsible for the long latency of the stretch response in contracting muscle was first suggested by CG Philips in 1968 and who also coined the term “ transcortical stretch reflex,”[ 14 15 ] the idea was brilliantly exploited by Merton in collaboration with Marsden and Morton from the late 1960s to the mid-1980s and the three of them started a famous collaboration in the Institute of Neurology, Queen Square which formed the famous “ 3M ” team of the 1970s. During this period, he was a frequent overnight user of the computer at the National Physical Laboratory since it was the only machine powerful enough at the time to produce accurate frequency analysis of tremor records.…”

Combined effects of 12-week yoga warm-up on athletic performance in male high school track and field athletes

“…We analyzed that yoga could effectively improve flexibility from two aspects. First, the practice of yoga was not likely to induce stretch reflexes [37]. The practice of yoga involved short active contractions of the stretched muscle before stretching, which may reduce the sensitivity of muscle spindles and allow for greater stretches.…”