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Modulation of Stretch-Shortening-Cycle Behavior With Eccentric Loading of Triceps Surae: A Possible Therapeutic Mechanism.
J Sport Rehabil ; 26(2): 151-158, 2017 Apr.
Article en En | MEDLINE | ID: mdl-27632850
ABSTRACT
CONTEXT Eccentric exercises are increasingly being used to treat lower-limb musculoskeletal conditions such as Achilles tendinopathy. Despite widespread clinical application and documented efficacy, mechanisms underpinning clinical benefit remain unclear. Positive adaptations in motor performance are a potential mechanism.

OBJECTIVE:

To investigate how an eccentric loading intervention influences measures of stretch-shortening-cycle (SSC) behavior during a hopping task.

DESIGN:

Within-subjects repeated-measures observational study.

SETTING:

University motion-analysis laboratory.

PARTICIPANTS:

Healthy adults.

INTERVENTIONS:

A single intervention of 5 sets of 10 eccentric plantar-flexion contractions at 6 repetitions maximum using a commercial seated calf-raise machine. MAIN OUTCOME

MEASURES:

Lower-limb stiffness, sagittal-plane ankle kinematics, and temporal muscle activity of the agonist (soleus) and antagonist (tibialis anterior) muscles, measured during submaximal hopping on a custom-built sledge-jump system.

RESULTS:

Eccentric loading altered ankle kinematics during submaximal hopping; peak angle shifted to a less dorsiflexed position by 2.9° and ankle angle precontact shifted by 4.4° (P < .001). Lower-limb stiffness increased from 5.9 to 6.8 N/m (P < .001), while surface EMG measures of soleus occurred 14-44% earlier (P < .001) after the loading intervention.

CONCLUSIONS:

These findings suggest that eccentric loading alters SSC behavior in a manner reflective of improved motor performance. Decreased ankle excursion, increased lower-limb stiffness, and alterations in motor control may represent a positive adaptive response to eccentric loading. These findings support the theory that mechanisms underpinning eccentric loading for tendinopathy may in part be due to improved "buffering" of the tendon by the neuromuscular system.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Extremidad Inferior / Ejercicios de Estiramiento Muscular / Contracción Isométrica / Articulación del Tobillo Tipo de estudio: Observational_studies Límite: Adult / Female / Humans / Male Idioma: En Revista: J Sport Rehabil Asunto de la revista: MEDICINA ESPORTIVA / REABILITACAO Año: 2017 Tipo del documento: Article Pais de publicación: EEUU / ESTADOS UNIDOS / ESTADOS UNIDOS DA AMERICA / EUA / UNITED STATES / UNITED STATES OF AMERICA / US / USA

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Extremidad Inferior / Ejercicios de Estiramiento Muscular / Contracción Isométrica / Articulación del Tobillo Tipo de estudio: Observational_studies Límite: Adult / Female / Humans / Male Idioma: En Revista: J Sport Rehabil Asunto de la revista: MEDICINA ESPORTIVA / REABILITACAO Año: 2017 Tipo del documento: Article Pais de publicación: EEUU / ESTADOS UNIDOS / ESTADOS UNIDOS DA AMERICA / EUA / UNITED STATES / UNITED STATES OF AMERICA / US / USA