Oxygenation trends in vastus lateralis muscle during incremental and intense anaerobic cycle exercise in young men and women

Abstract

The purposes of this study were to compare the acute cardiorespiratory responses and muscle oxygenation trends during incremental cycle exercise to exhaustion with those observed during 30 s and 45 s Wingate tests in healthy men and women, and to examine the relationships between selected variables among these tests. Seventeen healthy junior badminton players, nine men [mean age, height, body mass and maximal oxygen uptake (VO2max) were 15.8 (SD 0.8) years, 1.73 (SD 0.08) m, 65.6 (SD 6.3) kg and 50.6 (SD 6.9) ml x kg(-1) x min(-1) respectively] and eight women [mean age, height, body mass and VO2max were 16.6 (SD 1.0) years, 1.65 (SD 0.03) m, 62.7 (SD 4.5) kg and 42.0 (SD 5.0) ml x kg(-1) x min(-1) respectively] completed a stepwise incremental exercise test to voluntary exhaustion and two Wingate tests lasting 30 s and 45 s in three separate sessions in random order. Cardiorespiratory responses were monitored breath-by-breath using a metabolic cart interfaced with an electrocardiogram. Tissue absorbancy trends were continuously recorded from the right vastus lateralis muscle using dual wavelength near infrared spectroscopy. Oxygen uptake and heart rate were significantly higher during the incremental test when compared to the two Wingate tests in the men and women. However, the oxygen pulse (oxygen utilization per heart beat, i.e., the product of stroke volume and arterio-venous oxygen difference) was not significantly different among the three tests in both sexes. The minimal tissue absorbancy, an index of muscle deoxygenation, was also not significantly different among the three tests in both sexes. Significant relationships were observed for the oxygen uptake (r2=0.72) and oxygen pulse (r2=0.60) between the incremental and 45 s Wingate tests in the sample for both sexes combined. The minimal tissue absorbancy, however, was not significantly related between the two tests. It was concluded that the significantly higher oxygen uptake during the incremental test was due to the higher heart rate because: firstly, oxygen pulse was not significantly different among the three tests, and secondly, peripheral factors, as indicated by the changes in muscle oxygenation, were not significantly different among the three test conditions. Although the peak values of the oxygen pulse during the incremental and 45 s Wingate tests were significantly correlated, the common variance of the minimal tissue absorbancy measurements between these two tests was quite low, suggesting considerable variation in the peripheral contribution during these two tests.

Effects of Hypoxia on the Onset of Muscle Deoxygenation and the Lactate Threshold

“…These relationships may be explained by our observations, as well as those of others [2,5,6], that under hypoxic conditions the LT occurred at a lower exercise intensity compared to that seen during normoxia. It is generally believed that during hypoxia there is greater sympathetic nervous system activation, which stimulates glycogenolysis and glycolysis, thus contributing to increased lactate accumulation [4,5,7,8].…”

“…Furthermore, when graded exercise is performed under hypoxic conditions, the LT is shifted leftward and occurs at a lower absolute intensity than what is observed under normoxia [2,4,5]. Whether there would be a similar shift in the onset of muscle deoxygenation (OMD) under hypoxia is unknown; thus we have undertaken this study.…”

“…Previous studies [1][2][3] have reported a predictable decrease in muscle oxygen saturation (S t O 2 ) during exercise as measured by near-infrared spectroscopy (NIRS). Moreover, a distinct breakpoint of accelerated muscle deoxygenation occurs at the lactate threshold (LT), as evidenced by a high correlation between the two parameters during graded exercise [1,3].…”

Comparisons of local and systemic aerobic fitness parameters between finswimmers with different athlete grade levels

“…At workloads corresponding to thresholds and exhaustion, there was significant difference in _ VO 2 but no significant difference in _ V E between groups, reflecting better ability of oxygen intake in the HL group with no significant difference in ventilation between groups at thresholds and exhaustion. Furthermore, significant higher O 2 pulse in the HL group at thresholds and exhaustion indicated higher systemic oxygen uptake per heart beat, and suggested higher stroke volume (Bhambhani et al 2001(Bhambhani et al , 2010 in the HL group during intensive exercise. The higher stroke volume in the HL group, together with no significant difference in HR between groups at thresholds and exhaustion, meant that the HL group owned higher cardiac output (product of stroke volume and HR), which provided the probability to transfer more blood to the local skeletal muscles at each heart beat for the HL group during intensive exercise.…”

“…During the incremental exercise test, after a 3-min rest seated on an electronically braked cycle ergometer (Lode Examiner, Lode VL, Groningen, Netherlands), the subjects performed an incremental cycling exercise at a pedaling rate of 60 rpm. The incremental cycling exercise started at an initial workload of 40 W, followed by increments of 30 W every 3 min (Bentley et al 2007) until volitional fatigue or two of the following criteria (Bhambhani et al 2001;Zhang et al 2010) were attained: (1) heart rate (HR) C age-predicted maximal HR, which was calculated as 220 (age in years);…”