Submax iso research

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Anton Ušaj1

1Faculty of Sport, Gortanova 22, University of Ljubljana, 1000

Ljubljana, Slovenia

Abstract

The aim of the study was to find the influence of training on the

oxygenation status of a forearm muscle during submaximal isometric

contraction. Six subjects performed a test of isometric contraction

of a forearm muscle by continuous pressing of a handgrip dynamometer

with a force of 15 kp, until exhaustion. The continuous measurements

of oxygen saturation (%) (OXY), concentration of oxygenated

haemoglobin (wM) (OXYHb), deoxygenated haemoglobin (wM) (DEOXYHb) and

total haemoglobin (wM) (TOTHb) in blood, which passed through the

muscle, were made by the near infrared spectroscope Oxymeter 96208

(ISS, USA). This test was repeated before and after the four weeks

training period, which consisted of 5 continuous isometric

contractions of 30 s at the beginning and of 1:15 min during the last

week. Training did not significantly influence maximal isometric

force (55.5 - 10 kp before, 60.2 - 9 kp after). On the other hand,

the duration of isometric contraction increased from 271 - 117 s to

388 - 152 s (P < 0.05). Subjects were substantially different in

duration of muscle contraction and also in oxygenation status during

the contractions. Therefore, the relationship between these

parameters and the training effect was calculated. The training

effect was represented as the difference between the duration of

muscle contraction before and after the training period. This

parameter significantly correlated with relative oxygen saturation

(r=-0.88; P < 0.05) and with relative concentration of deoxygenated

haemoglobin (r = 0.87; P < 0.05). These results demonstrated the

importance of individual training adaptations of forearm muscles. The

increase of the duration of submaximal isometric contraction, as a

training effect, can be dependent on larger muscle deoxygenation.

Keywords