The endurance training effect on the oxygenation status of an isometrically contracted forearm muscle

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 (pM) (OXYHb), deoxygenated haemoglobin (pM) (DEOXYHb) and total haemoglobin (pM) (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 f 10 kp before, 60.2 k 9 kp after). On the other hand, the duration of isometric contraction increased from 27 1 k 1 17 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.

Quadriceps Muscle Fatigue in Trained and Untrained Boys

“…The higher Deoxy[Hb + Mb]-increase in specifi cally trained subjects suggests that they show a higher increase in capillary O 2 -extraction, compared to untrained controls. This is in line with the results of Usaj [ 33 ] which showed that after 4 weeks of endurance training an increase in relative deoxygenated haemoglobin concentration and endurance time during sustained submaximal isometric handgrip exercise (at 30 % MVC) was visible. The author suggested that a certain number of capillaries may open as a result of isometric endurance training, increasing O 2 consumption capacity as a result of increased O 2 availability.…”

“…Isometric contraction is characterized by restricted local blood fl ow [ 10 , 27 , 34 ] , since the intramuscular pressure increases even at very low isometric contraction intensities [ 9 ] . Therefore, the delivery of oxygen and wash out of muscle metabolites may become limited, which aff ects the duration of such a contraction [ 33 ] . However, literature suggests that when fatiguing isometric contractions are performed at low levels ( ≤ 30 % ments from the M. Vastus Lateralis.…”

Application of Near Infrared Spectroscopy to Exercise Sports Science

“…To date, four studies have used NIRS to examine the effects of exercise training on muscle deoxygenation: Costes et al (2001); Usaj (2001); and Puente-Maestu et al (2003). These studies all showed that NIRS is a promising technique that could be used to examine the influence of exercise training on muscle oxygenation and reoxygenation following exercise (Table 2).…”

“…In the study by Usaj (2001), the use of NIRS in a group of 6 male subjects showed that a 4-week endurance-training program of the forearm musculature increased submaximal isometric contraction duration. Although maximal isometric force development with training was not significantly affected, the increased duration of submaximal contraction was likely related to changes in muscle characteristics with training, and this resulted in part in an observed greater deoxygenation before termination of muscular contraction.…”

The influence of strength-endurance training on the oxygenation of isometrically contracted forearm muscles

“…Squeezing of a rubber ring at an intensity of about 30% of Maximal Voluntary Contraction (MVC) to fatigue, using single and multiple repetitions during a single training session and separated by suYcient recovery intervals, may increase the duration of isometric contractions of forearm muscles (Unaj 2001). A positive training eVect could occur mainly at intensities and durations corresponding to training intensity.…”