Document Type

Thesis - Open Access

Award Date

2018

Degree Name

Master of Science (MS)

Department

Health and Nutritional Sciences

First Advisor

Gary Van Guilder

Keywords

Ischemia, reperfusion, anaerobic performance, oxygen uptake, accumulated oxygen deficit

Abstract

Purpose: There is an ongoing debate concerning whether ischemic preconditioning elicits consistent and meaningful exercise performance benefits. We have previously demonstrated no performance benefits of ischemic preconditioning at submaximal aerobic exercise intensities. It is likely that the beneficial effects of ischemic preconditioning on performance only involve supramaximal anaerobic exercise bouts, which elicit greater metabolic and neuromuscular stress. The aim of the study was to test the hypothesis that ischemic preconditioning improves maximal accumulated oxygen deficit (aO2D), an indicator of anaerobic capacity, in NCAA Division I middle-distance runners. Methods: A randomized sham-controlled crossover study was employed in which 10 NCAA Division I middle-distance (800 to 1600 meter) track athletes (age: 21±1 yr; VO2 max: 65±7 mlO2·kg·-1·min-1) completed three supramaximal treadmill running trials (110% VO2max; ~12.6 mph @ 5% grade) to volitional exhaustion coupled with indirect calorimetry to assess maximal aO2D at baseline, after a sham control trial (mock preconditioning), and with limb-based ischemic preconditioning (4×5 min cycles of brachial artery ischemia/reperfusion). Maximal aO2D (mlO2·kg-1) for each trial was determined by first calculating the theoretical oxygen demand required for the supramaximal running bout (linear regression extrapolated from 9×5 min submaximal running stages). The actual oxygen demand measured during the supramaximal bout was then subtracted from the theoretical value to obtain the aO2D. Statistical Analysis: A three-way repeated-measures ANOVA with adjustment for multiple comparisons was used for within-group differences (i.e., baseline vs sham vs ischemic preconditioning) in aO2D. Results: Ischemic preconditioning (122±38 sec) increased (P=0.0001) supramaximal time to exhaustion by 22% compared with both baseline (99±23 sec, 95% CI: 4.8-40.6, P=0.014) and sham (101±30 sec 95% CI: 6.7-34.2, P=0.001). Effect size for these trial differences as estimated by the Partial Eta2 (0.58) were large. Furthermore, the aO2D was considerably greater (P=0.009) with ischemic preconditioning. During their supramaximal run in the presence of ischemic preconditioning, aO2D was 46±35 mlO2·kg-1, a substantial (Partial Eta2 = 0.43) increase compared with baseline (35±27 mlO2·kg-1, P=0.025, 95% CI:1.3-19.2) and sham (38±32 mlO2·kg-1, P=0.046, 95% CI: 0.13-14.0). There were no statistical differences in time to exhaustion and maximal aO2D between baseline and sham. Conclusions: Limb-based ischemic preconditioning considerably improves time to exhaustion and anaerobic capacity as measured by the maximal aO2D in NCAA Division I middle-distance track athletes. Additional work is needed to confirm whether these laboratory-based performance benefits can be translated to better outcomes in real track meets in elite athletes seeking a competitive advantage.

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

34

Publisher

South Dakota State University

Rights

In Copyright - Non-Commercial Use Permitted
http://rightsstatements.org/vocab/InC-NC/1.0/

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