Mendez-Rebolledo G, Gatica-Rojas V, Guzman-Muñoz E, Martinez-Valdes E, Guzman-Venegas R, Berral de la Rosa FJ. Influence of fatigue and velocity on the latency and recruitment order of scapular muscles.
Phys Ther Sport 2018;
32:80-86. [PMID:
29775865 DOI:
10.1016/j.ptsp.2018.04.015]
[Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Revised: 03/31/2018] [Accepted: 04/17/2018] [Indexed: 11/24/2022]
Abstract
OBJECTIVES
To determine the influence of velocity and fatigue on scapular muscle activation latency and recruitment order during a voluntary arm raise task, in healthy individuals.
DESIGN
Cross-sectional study.
SETTING
University laboratory.
PARTICIPANTS
Twenty three male adults per group (high-velocity and low-velocity).
MAIN OUTCOME MEASURES
Onset latency of scapular muscles [Anterior deltoid (AD), lower trapezius (LT), middle trapezius (MT), upper trapezius (UT), and serratus anterior (SA)] was assessed by surface electromyography. The participants were assigned to one of two groups: low-velocity or high-velocity. Both groups performed a voluntary arm raise task in the scapular plane under two conditions: no-fatigue and fatigue.
RESULTS
The UT showed early activation (p < 0.01) in the fatigue condition when performing the arm raise task at a high velocity. At a low velocity and with no muscular fatigue, the recruitment order was MT, LT, SA, AD, and UT. However, the recruitment order changed in the high-velocity with muscular fatigue condition, since the recruitment order was UT, AD, SA, LT, and MT.
CONCLUSIONS
The simultaneous presence of fatigue and high-velocity in an arm raise task is associated with a decrease in the UT activation latency and a modification of the recruitment order of scapular muscles.
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