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#### Article Title

Sensitivity of Prescribing High-Intensity, Interval Training Using the Critical Power Concept

#### Abstract

** International Journal of Exercise Science 8(3): 202-212, 2015.** The critical power (

*CP*) concept enables the calculation of time to exhaustion (t

_{LIM}) for a given power output above

*CP*using the equation of t

_{LIM}=

*W’*/(power –

*CP*), where

*W’*is the curvature constant, and

*CP*is the asymptote for the power-t

_{LIM}relationship. The

*CP*concept offers great promise for prescribing high-intensity interval training (HIIT); however, knowledge on the concept’s sensitivity is lacking (i.e., how much of a difference in

*W’*expenditure is needed to evoke different metabolic responses). We tested if two different power-t

_{LIM}configurations expending identical proportions of

*W’*would evoke different end-exercise oxygen uptake (VO

_{2}) and heart rate (HR) values. Five men and five women completed a graded exercise test, 3-min all-out exercise tests, and intervals prescribed to deplete either 70 or 80% of

*W’*on separate visits. Consistency statistics of intraclass correlation (ICC a), standard error of measure (SEM), and coefficient of variation (CV) were calculated on end-exercise values. End-exercise VO

_{2}were similar for the 3.5- and 5-min bouts, depleting 70% of

*W’*(ICC a = 0.91, SEM = 3.23 mL·kg

^{-1}·min

^{-1}, CV = 8.1%) and similar for the 4- and 5-min bouts, depleting 80% of

*W’*(ICC a = 0.95, SEM = 2.34 mL·kg

^{-1}·min

^{-1}, CV = 8.1%). No VO

_{2}differences were observed between trials or conditions (p = 0.58). Similarly, HR values (~181 b·min

^{-1}) did not differ between trials or conditions (p = 0.45). Use of the CP concept for HIIT prescriptions of different power-t

_{LIM}configurations evokes similar end-exercise VO

_{2}values on a given day. Our findings indicate that >10%

*W’*depletion is necessary to evoke different metabolic responses to HIIT.

#### Recommended Citation

Pettitt, Robert W.; Placek, Ashley M.; Clark, Ida E.; Jamnick, Nicholas A.; and Murray, Steven R.
(2015)
"Sensitivity of Prescribing High-Intensity, Interval Training Using the Critical Power Concept,"
*International Journal of Exercise Science*:
Vol. 8:
Iss.
3, Article 1.

Available at:
http://digitalcommons.wku.edu/ijes/vol8/iss3/1