The study aimed to evaluate the stretch-induced changes in muscle architecture in different portions of the gastrocnemius medialis (GM) and lateralis (GL) muscles. The reliability and sensitivity of the measurements were also assessed. Fascicle length (FL) and pennation angle (PA) were calculated in the middle and distal portions of GM and GL at 0 degrees, 10 degrees and 20 degrees of ankle dorsiflexion. At the same angles, passive torque (Tpass), peak torque (pT) and myotendinous junction displacement of GM were determined. Stiffness was calculated at muscle-tendon unit (MTU), muscle and tendon level. After static stretching administration, Tpass, pT and MTU stiffness decreased by 22%, 12% and 16%, respectively (p < 0.05). Muscle and tendon stiffness decreased by 15% and 16% (p < 0.05). Nevertheless, no changes in FL and PA occurred. The reliability of the approach was always very high (intraclass correlation coefficient > 0.90), with an adequate level of sensitivity. pT after static stretching was related to decreases in MTU, muscle and tendon stiffness, but not to alterations in muscle architecture. (C) 2015 Elsevier Ltd. All rights reserved.

Stretch-induced changes in tension generation process and stiffness are not accompanied by alterations in muscle architecture of the middle and distal portions of the two gastrocnemii

Limonta, E.;Venturelli, M.;
2015

Abstract

The study aimed to evaluate the stretch-induced changes in muscle architecture in different portions of the gastrocnemius medialis (GM) and lateralis (GL) muscles. The reliability and sensitivity of the measurements were also assessed. Fascicle length (FL) and pennation angle (PA) were calculated in the middle and distal portions of GM and GL at 0 degrees, 10 degrees and 20 degrees of ankle dorsiflexion. At the same angles, passive torque (Tpass), peak torque (pT) and myotendinous junction displacement of GM were determined. Stiffness was calculated at muscle-tendon unit (MTU), muscle and tendon level. After static stretching administration, Tpass, pT and MTU stiffness decreased by 22%, 12% and 16%, respectively (p < 0.05). Muscle and tendon stiffness decreased by 15% and 16% (p < 0.05). Nevertheless, no changes in FL and PA occurred. The reliability of the approach was always very high (intraclass correlation coefficient > 0.90), with an adequate level of sensitivity. pT after static stretching was related to decreases in MTU, muscle and tendon stiffness, but not to alterations in muscle architecture. (C) 2015 Elsevier Ltd. All rights reserved.
Electrically-evoked contraction
Fascicle length
Pennation angle
Plantar flexor muscles
Adult
Ankle Joint
Ergometry
Humans
Male
Muscle Spindles
Muscle Stretching Exercises
Muscle, Skeletal
Range of Motion, Articular
Reproducibility of Results
Tendons
Young Adult
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11562/1071788
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