Chronic effects of muscle and nerve-directed stretching on tissue mechanics

This study demonstrates that the mechanical properties of plantar flexor muscles and sciatic nerve can adapt mechanically to long-term stretching programs. Although interventions targeting muscular or nonmuscular structures are both effective at increasing maximal range of motion, the changes in tissue mechanical properties (stiffness) are specific to the structure being preferentially stretched by each program. We provide the first in vivo evidence that stiffness of peripheral nerves adapts to long-term loading stimuli using appropriate nerve-directed stretching.

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Effects of a Single Proprioceptive Neuromuscular Facilitation Stretching Exercise With and Without Post-stretching Activation on the Muscle Function and Mechanical Properties of the Plantar Flexor Muscles

Frontiers in Physiology ◽

10.3389/fphys.2021.732654 ◽

2021 ◽

Vol 12 ◽

Author(s):

Marina Reiner ◽

Markus Tilp ◽

Gaël Guilhem ◽

Antonio Morales-Artacho ◽

Masatoshi Nakamura ◽

...

Keyword(s):

Mechanical Properties ◽

Shear Modulus ◽

Muscle Function ◽

Peak Torque ◽

Neutral Position ◽

Plantar Flexor ◽

Maximum Voluntary Isometric Contraction ◽

Proprioceptive Neuromuscular Facilitation ◽

Flexor Muscles ◽

Plantar Flexor Muscles

A single proprioceptive neuromuscular facilitation (PNF) stretching exercise can increase the range of motion (ROM) of a joint but can lead to a decrease in performance immediately after the stretching exercise. Post-stretching activation (PSA) exercises are known as a possible way to counteract such a drop in performance following a single stretching exercise. However, to date, no study has investigated the combination of PNF stretching with PSA. Thus, the aim of this study was to compare the effects of a PNF stretching exercise with and without PSA on the muscle function (e.g., ROM) and mechanical properties of the plantar flexor muscles. Eighteen physically active males volunteered in the study, which had a crossover design and a random order. The passive shear modulus of the gastrocnemius medialis (GM) and gastrocnemius lateralis (GL) was measured in a neutral position with shear wave elastography, both pre- and post-intervention. Maximum voluntary isometric contraction (MVIC) peak torque, maximum voluntary dynamic contraction peak torque, dorsiflexion ROM, and passive resistive torque (PRT) were also measured with a dynamometer. The interventions were 4×30s of PNF stretching (5s of contraction) and two sets of three exercises with 20 or 40 fast ground contacts (PNF stretching+PSA) and PNF stretching only. ROM was found to have increased in both groups (+4%). In addition, the PNF stretching+PSA group showed a decrease in PRT at a given angle (−7%) and a decrease in GM and mean shear modulus (GM+GL; −6%). Moreover, the MVIC peak torque decreased (−4%) only in the PNF stretching group (without PSA). Therefore, we conclude that, if PNF stretching is used as a warm-up exercise, target-muscle-specific PSA should follow to keep the performance output at the same level while maintaining the benefit of a greater ROM.

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Changes in mechanical properties of human plantar flexor muscles in ageing

Experimental Gerontology ◽

10.1016/j.exger.2003.11.004 ◽

2004 ◽

Vol 39 (3) ◽

pp. 349-358 ◽

Cited By ~ 48

Author(s):

Julien Ochala ◽

Daniel Lambertz ◽

Michel Pousson ◽

Francis Goubel ◽

Jacques Van Hoecke

Keyword(s):

Mechanical Properties ◽

Plantar Flexor ◽

Flexor Muscles ◽

Plantar Flexor Muscles

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In vivo evidence of an age-related increase in ATP cost of contraction in the plantar flexor muscles

Clinical Science ◽

10.1042/cs20130442 ◽

2013 ◽

Vol 126 (8) ◽

pp. 581-592 ◽

Cited By ~ 28

Author(s):

Gwenael Layec ◽

Joel D. Trinity ◽

Corey R. Hart ◽

Seong-Eun Kim ◽

Henderik Jonathan Groot ◽

...

Keyword(s):

Skeletal Muscle ◽

Exercise Capacity ◽

The Elderly ◽

Plantar Flexor ◽

Age Related ◽

Flexor Muscles ◽

Response To Exercise ◽

Plantar Flexor Muscles ◽

Related Increase

The present study reveals that impaired skeletal muscle efficiency potentially contributes to the age-related decline in exercise capacity and may explain the altered haemodynamic response to exercise in the elderly.

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