A Model for Identifying Intensity Zones Above Critical Velocity

Abstract

Bergstrom, HC, Housh, TJ, Cochrane-Snyman, KC, Jenkins, NDM, Byrd, MT, Switalla, JR, Schmidt, RJ, and Johnson, GO. A model for identifying intensity zones above critical velocity. J Strength Cond Res 31(12): 3260-3265, 2017-The purpose of this study was to describe the V[Combining Dot Above]O2 responses relative to V[Combining Dot Above]O2peak at 4 different intensities within the severe domain and, based on the V[Combining Dot Above]O2 responses, identify intensity zones above critical velocity (CV). Twelve runners (mean ± SD age = 23.2 ± 3.0 years) performed an incremental treadmill test (ITT) to exhaustion to determine the V[Combining Dot Above]O2peak and velocity associated with V[Combining Dot Above]O2peak (vV[Combining Dot Above]O2peak). Critical velocity was determined from 4 exhaustive, constant velocity, randomly ordered treadmill runs (V1, V2, V3, and V4; V1 = highest, V4 = lowest). The V[Combining Dot Above]O2 responses were recorded during each of the constant velocity runs. Mean differences among V[Combining Dot Above]O2peak values from the ITT and the highest value recorded during the constant velocity runs were examined. The V[Combining Dot Above]O2 values at exhaustion for V1 (3.32 ± 0.10 L·min, p = 0.15) and V2 (3.27 ± 0.91 L·min, p = 0.13) were not significantly different from V[Combining Dot Above]O2peak (3.39 ± 0.96 L·min) from the ITT. The V[Combining Dot Above]O2 values at exhaustion for V3 (3.18 ± 0.88 L·min; p = 0.007) and V4 (3.09 ± 0.86 L·min; p = 0.003), however, were significantly less than the V[Combining Dot Above]O2peak from the ITT. There were intensity-dependent V[Combining Dot Above]O2 responses above CV. Based on these findings, we have hypothesized 3 intensity zones (first severe intensity zone [SIZ1], second severe intensity zone [SIZ2], and extreme intensity zone [EIZ]) within the severe and extreme domains, which are characterized by specific V[Combining Dot Above]O2 responses and may be used to design programs that maximize aerobic performance adaptations.

The Sensitivity of the Critical Resistance Model to Detect Sex-Related Differences in Fatigue During Submaximal Muscular Contractions

“…The CR is derived from the slope of the highly linear relationship between total work (resistance × repetitions) and the number of muscular contractions completed to failure. In the present study, the R 2 and SEE values for the combined sample were 0.965 ± 0.034 kg and 110.9 ± 45.9 kg, respectively. The R 2 values in the present study (R 2 = 0.864-0.994) were consistent with those (R 2 = 0.996-1.00) previously reported for the relationship between time to exhaustion and total work for both critical power and critical velocity [1][2][3][4], and for the three-parameter non-linear relationship between resistance and repetitions completed (R 2 = 0.670-1.00) for the bench press [16].…”

“…In the present study, the R 2 and SEE values for the combined sample were 0.965 ± 0.034 kg and 110.9 ± 45.9 kg, respectively. The R 2 values in the present study (R 2 = 0.864-0.994) were consistent with those (R 2 = 0.996-1.00) previously reported for the relationship between time to exhaustion and total work for both critical power and critical velocity [1][2][3][4], and for the three-parameter non-linear relationship between resistance and repetitions completed (R 2 = 0.670-1.00) for the bench press [16]. Thus, the R 2 values reported in the present study indicate that the model used to identify critical power, critical velocity, and CR for an upper body-specific DCER exercise can be expanded to a full body DCER exercise.…”

Methodological Approaches and Related Challenges Associated With the Determination of Critical Power and Curvature Constant

“…However, some studies have reported that V O2 did not reach its maximum at task-failure during the longest predictive trials, which corresponded to intensities slightly (~10%) above CP (11,94). The reason(s) for this phenomenon remain unknown, but it is likely to be multifactorial, including physiological and/or psychophysiological factors (1, 11,94). Therefore, it is recommended that exhaustive trials which result in Tlim >15 min should be avoided as V O2max may not be reached.…”

“…On the other hand, exercise performed above CP and continued for >2 min should lead to maximal values of V O2 and blood lactate concentration (19,25,88). However, some studies have reported that V O2 did not reach its maximum at task-failure during the longest predictive trials, which corresponded to intensities slightly (~10%) above CP (11,94). The reason(s) for this phenomenon remain unknown, but it is likely to be multifactorial, including physiological and/or psychophysiological factors (1, 11,94).…”

High-Intensity Interval Training Prescribed Within the Secondary Severe-Intensity Domain Improves Critical Speed But Not Finite Distance Capacity

“…The tolerable duration of exercise (t LIM ) at intensities above CS, termed the "severe intensity domain", is therefore highly predictable, lending itself well to exercise programming within this intensity domain [17,30,37]. Moreover, intensities between 50% Δ (Δ = difference between CS and sVO 2max ) and 175% CS (termed the secondary severe intensity domain [SSID]) have reported distinct VO 2 responses compared to "lower" intensities, implying that the severe intensity domain itself may be sub-categorized [3]. More importantly, the t LIM of exercise within the severe intensity domain is proportional to the magnitude of D′, therefore surmising that an improvement in D′ would extend t LIM and improve performance within this domain.…”