Abstract
Maximal oxygen uptake (VO2max) and critical speed (CS) are key fatigue-related measurements that demonstrate a relationship to one another and are indicative of athletic endurance performance. This is especially true for those that participate in competitive fitness events. However, the accessibility to a metabolic analyzer to accurately measure VO2max is expensive and time intensive, whereas CS may be measured in the field using a 3 min all-out test (3MT). Therefore, the purpose of this study was to examine the relationship between VO2max and CS in high-intensity functional training (HIFT) athletes. Twenty-five male and female (age: 27.6 ± 4.5 years; height: 174.5 ± 18.3 cm; weight: 77.4 ± 14.8 kg; body fat: 15.7 ± 6.5%) HIFT athletes performed a 3MT as well as a graded exercise test with 48 h between measurements. True VO2max was determined using a square-wave supramaximal verification phase and CS was measured as the average speed of the last 30 s of the 3MT. A statistically significant and positive correlation was observed between relative VO2max and CS values (r = 0.819, p < 0.001). Based on the significant correlation, a linear regression analysis was completed, including sex, in order to develop a VO2max prediction equation (VO2max (mL/kg/min) = 8.449(CS) + 4.387(F = 0, M = 1) + 14.683; standard error of the estimate = 3.34 mL/kg/min). Observed (47.71 ± 6.54 mL/kg/min) and predicted (47.71 ± 5.7 mL/kg/min) VO2max values were compared using a dependent t-test and no significant difference was displayed between the observed and predicted values (p = 1.000). The typical error, coefficient of variation, and intraclass correlation coefficient were 2.26 mL/kg/min, 4.90%, and 0.864, respectively. The positive and significant relationship between VO2max and CS suggests that the 3MT may be a practical alternative to predicting maximal oxygen uptake when time and access to a metabolic analyzer is limited.
Highlights
The use of physiological testing informs the sports performance coach and sports scientist about competitive athletic success as well as aids in development of endurance training programs by Sports 2020, 8, 155; doi:10.3390/sports8120155 www.mdpi.com/journal/sportsSports 2020, 8, 155 prescribing and monitoring training loads to elicit positive physiological adaptations
To calculate this, speed equaled the incremental stage change value divided by four, as data was averaged every 15 s and stage speed increased each minute. These calculations were used to determine the average of the speeds at gas exchange threshold (GET) and VO2max (50% ∆) to confirm critical speed (CS) results from the 3 min all-out test (3MT) [30]
Calculating 50% ∆ allowed us to screen for pacing during the 3MT as critical power (CP) is the approximate mean value (50% ∆) for power evoking gas exchange threshold (GET) and VO2max, as determined from a graded exercise test (GXT) [31]
Summary
Sports 2020, 8, 155 prescribing and monitoring training loads to elicit positive physiological adaptations The applications of these measurements include the assessment of aerobic fitness, the prescription of exercise training workouts, and the prediction of endurance performance [1,2,3,4,5]. The accuracy of aerobic/anaerobic thresholds are influenced by several intrinsic and extrinsic variables [15,16,17] as well as various methodological techniques [18,19] This has led to the use of several submaximal and field tests, as well as other technology, to assess endurance performance
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