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Intramuscular water movement during and after isometric muscle contraction: evaluation at different exercise intensities
Author(s) -
Yanagisawa Osamu,
Kurihara Toshiyuki
Publication year - 2016
Publication title -
clinical physiology and functional imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.608
H-Index - 67
eISSN - 1475-097X
pISSN - 1475-0961
DOI - 10.1111/cpf.12239
Subject(s) - isometric exercise , medicine , cardiology , exercise intensity , tibialis anterior muscle , effective diffusion coefficient , intensity (physics) , ankle , physical exercise , magnetic resonance imaging , skeletal muscle , anatomy , heart rate , blood pressure , radiology , physics , quantum mechanics
Summary We aimed at evaluating the effect of isometric muscle contraction on intramuscular water movement at different exercise intensities. Seven men performed 1‐min isometric ankle dorsiflexion (20% and 50% maximal voluntary contractions [ MVC s]) with a non‐magnetic custom‐made dynamometer, inside a magnetic resonance ( MR ) device. Axial diffusion‐weighted images were obtained before, during and at 1–20 min (1‐min interval) after the exercise to calculate the apparent diffusion coefficient ( ADC ) of the tibialis anterior. Under the same exercise condition, the concentration change of total haemoglobin ( H b) and myoglobin ( M b) (total H b/ M b) within the tibialis anterior was assessed by performing near‐infrared spectroscopy before, during and after the exercise outside the MR device. The 20% MVC exercise significantly increased the ADC only at 1 min postexercise ( P< 0·01), whereas the ADC significantly increased during and at 2–20 min after the 50% MVC exercise ( P <0·01). The 20% MVC exercise decreased the total H b/ M b during exercise ( P< 0·01), but the value significantly increased at 1 min postexercise ( P< 0·01). The total H b/ M b significantly decreased during the 50% MVC exercise, but significantly increased at 1–5 min postexercise ( P< 0·01). One‐minute moderate‐intensity isometric exercise activates intramuscular water movement during and after the exercise. This activation was found even after a low‐intensity exercise, but the effect was small and did not last long. The effect of intramuscular hyperaemia on the postexercise ADC elevation may be limited to the very early period after low‐ to moderate‐intensity exercises.