C-15J Free Communication/Poster Anaerobic Threshold
This investigation compared anaerobic threshold (AT) measurements using near infrared spectroscopy (NIRS) and ventilation (V-slope, ventilatory equivalents, and excess CO2) detection methods.
Twenty two males (age 24.2 ± 3.5 yr) and 22 females (age 21.1 ± 3.5 yr) participated as subjects. All subjects completed a single incremental cycle ergometer exercise test to exhaustion during which ventilatory gas exchange variables were obtained using open circuit spirometry. Vastus lateralis oxygenation values were obtained using NRIS. The cycle ergometer test consisted of increasing power output (50 W for males and 25 W for females) every 3 min.
Student t-tests indicated males had higher (p < 0.05) values for height, weight, age, VO2peak (L/min), and maximum power output (W). Females had higher (p < 0.05) percent body fat and total exercise time. Significant (p < 0.05) gender specific correlations for measurements of AT were noted between the NIRS and V-slope (r = 0.85, r = 0.78), ventilatory equivalents (r = 0.68, r = 0.50), and excess CO2 (r = 0.91, r = 0.83), for males and females, respectively. A 2-factor (method × sex) ANOVA indicated sex differences (p < 0.05) with respect to VO2(L/min), percent VO2peak, power output (W), and time at the AT. The percent VO2peak and power (W) at the AT were higher (p < 0.05) for the NIRS than ventilation methods. No other differences for measures of the AT were noted between methods.
These data suggest that the use of the non-invasive relatively inexpesive NIRS system is an acceptable method for the determination of AT. Further research is needed to determine the utility of NIRS in tracking training adaptations and assessing interindividual differences.