Middle-aged adults cocontract with arm ADductors during arm ABduction, while young adults do not. Adaptations to preserve pain-free function?
| Autor: | Arjen Kolk, Pieter Bas de Witte, Maaike G. J. Gademan, Jochem Nagels, Jurriaan H. de Groot, Rob G H H Nelissen, Celeste L. Overbeek |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Adult
Male medicine.medical_specialty Aging Movement Deltoid curve Biophysics Neuroscience (miscellaneous) Adductor cocontraction Electromyography Isometric exercise Upper Extremity 03 medical and health sciences 0302 clinical medicine Physical medicine and rehabilitation Shoulder Pain Deltoid muscle medicine Humans Humerus Acromion Range of Motion Articular Subacromial narrowing medicine.diagnostic_test Shoulder Joint business.industry 030229 sport sciences Deltoid Muscle Middle Aged Adaptation Physiological Joint stabilisation body regions Shoulder stability medicine.anatomical_structure Shoulder Impingement Syndrome Humeral depression Female Neurology (clinical) Adductor muscles business 030217 neurology & neurosurgery Muscle Contraction |
| Zdroj: | Journal of Electro-myography and Kinesiology, 49. ELSEVIER SCI LTD |
| Popis: | Middle-aged individuals cocontract with adductor muscles during abduction. This may be crucial for counteracting deltoid forces, depressing the humerus and ensuring free passage of subacromial tissues underneath the acromion during abduction. We questioned whether adductor co-contraction is always present, or develops during ageing, in which case it may explain the age-related character of common shoulder conditions such as Subacromial Pain Syndrome. In a cross-sectional analysis with electromyography (EMG), activation patterns of the latissimus dorsi, teres major, pectoralis major and deltoid muscle were assessed during isometric force tasks in 60 asymptomatic individuals between 21 and 60 years old. Cocontraction was expressed as the degree of antagonistic activation relative to the same muscle's degree of agonistic activation, resulting in an activation ratio between -1 and 1, where lower values indicate more cocontraction. Using linear regression analyses, we found age-related decreases in the activation ratio of the latissimus dorsi (regression estimate: -0.004, 95% CI: -0.007 to 0.0, p-value: 0.042) and teres major (regression estimate: -0.013, 95% CI: -0.019 to -0.008, p-value: < 0.001). In contrast to young individuals, middle-aged individuals showed a high degree of adductor cocontraction during abduction. This may indicate that during ageing, alterations in activation patterns are required for preserving pain-free shoulder function. |
| Databáze: | OpenAIRE |
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