Abstract

The study aimed to calculate training intensity and load using muscle oxygen saturation (SmO2) during two differentiated physical tasks. 29 university athletes participated in a 40-m Maximal Shuttle Run Test (MST, 10 x 40-m with 30 s recovery between sprints) and a 3000-m time trial run. Distance and time were used to calculate external load (EL). Internal load indicators were calculated based on percentage of maximum heart rate (%HRMAX) and SmO2 variables: muscle oxygen extraction (del%SmO2) and the cardio-muscle oxygen index (CMOI) was also provided by relating del%SmO2 divided by %HRMAX, and the training load were calculated as the product of speed (m/min x IL) and the efficiency index [Eff(index) (m/min divided by IL)]. A student t test was applied based on Bayesian factor analysis. As expected, EL differed in the 40-m MST (331 +/- 22.8) vs. 3000-m trials (222 +/- 56.8) [BF10 = 6.25e+6; p = <0.001]. Likewise, IL showed higher values in 40-m MST (39.20 +/- 15.44) vs. 3000-m (30.51 +/- 8.67) in CMOI: [BF10 = 1.70; p = 0.039]. Training load was greater in 40-m MST (85.77 +/- 27.40) vs. 3000-m (15.55 +/- 6.77) [(m/min x del%SmO2): BF10 = 12.5; p = 0.003] and 40-m MST (129.27 +/- 49.44) vs. 3000-m (70.63 +/- 32.98) [(m/min x CMOI): BF10 = 169.6; p = <0.001]. Also, the Effindex was higher in 40-m MST (10.19 +/- 4.17) vs. 3000-m (6.06 +/- 2.21) [(m/min x del%SmO2): BF10 = 137.03; p = <0.001] and 40-m MST (9.69 +/- 4.11) vs. 3000-m (7.55 +/- 1.87) [(m/min x CMOI): BF10 = 1.86; p = 0.035]. This study demonstrates calculations of training intensity and load based on SmO2 as an internal load indicator along with speed as an external load indicator during two differentiated exercises.