Date Approved

2017

Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department

Health Promotion and Human Performance

Committee Member

Rebecca Moore, PhD, Chair

Committee Member

Christopher Herman, PhD

Committee Member

Jeff Schulz, PhD

Abstract

Using accurate submaximal methodologies to estimate VO2max is a convenient alternative to maximal exercise testing. Submaximal testing is practical because it provides a cheaper, more time-efficient method to determine VO2max and allows a wider range of individuals to be tested. Purpose: The purpose of this study was to examine the predictability of VO2max using a GPS sports watch. Methods: Thirty participants, 16 males and 14 females between the ages of 18 and 55, volunteered for this study. A total of three separate VO2max values were recorded during the study: (a) directly measured VO2max, (b) a predicted VO2max value based on a 15-minute outdoor run, and (c) an adjusted predicted VO2max value based on three subsequent outdoor runs of at least 30 minutes in duration. Participants came to the Running Science Laboratory at Eastern Michigan University (EMU) on two separate occasions. On day one, participants completed a treadmill-based graded exercise test (GXT) to determine VO2max. Participants completed the test using a self-selected pace (mph) that was determined during a 3-minute warm-up period. The self-selected pace remained constant throughout the test while the grade increased at a rate of 2% every 2 minutes. On day two, participants arrived at EMU and completed a 15-minute submaximal outdoor run. Participants were fitted with a GPS sports watch, which was used to predict VO2max based on subject characteristics (gender, age, height [in], weight [lbs.]), as well as total distance of the run, pace, time (15 minutes), and heart rate (HR) during exercise. Participants were then required to take the watch home and record three additional runs of at least 30 minutes to produce an adjusted predicted VO2max value. A two-way (2 fitness groups x 3 VO2max time points) repeated measures ANOVA was conducted to determine if there was a significant difference between directly measured VO2max, predicted VO2max, and adjusted predicted VO2max. Participants were placed into two fitness groups determined by directly measured VO2max (VO2max of greater than [high] or less than [low] 50 ml/kg/min). A one-way repeated measures ANOVA was conducted to determine if a significant difference in recorded VO2max values was observed within groups. Statistical significance was determined using a p-value of .05. Results: Two participants (two males) were excluded from the analysis due to failing to return for visit two. The remaining 28 participants were 24.71 ± 5.69 years old, had a height of 168.94 ± 6.94 cm, and weighed 67.22 ± 14.85 kg. A statistically significant difference was observed between directly measured (55.09 ± 9.73 ml/kg/min) and predicted VO2max (51.75 ± 5.16 ml/kg/min);(p-value < .05), directly measured and adjusted predicted VO2max (50.68 ± 5.98 ml/kg/min);(p-value < .001), and predicted and adjusted predicted VO2max (p-value < .05). A significant difference was observed in the high VO2max group between directly measured and predicted VO2max and directly measured and adjusted predicted VO2max (p-value < .001). No significant difference was observed between predicted and adjusted predicted VO2max in the high VO2max group (p-value > .05). No significant difference was observed between values in the low VO2max group (p-value > .05). Conclusion: Major limitations of this study included participants performing all activities at a self-selected pace and measuring HR using the radial pulse with an optical sensor. A self-selected pace could have led to inaccuracies in VO2max prediction as participants may not have performed to their full potential. Future research could enforce stricter pace and distance requirements for additional activity recording to test both anaerobic and aerobic energy systems. Additionally, measuring HR using an optical sensor within the watch at the radial pulse has been shown to underestimate average HR values when compared to HR measurement using a chest strap. While the purpose of this study was to test the predictability of only the GPS sports watch, a lower overall average HR for a given activity could have produced overestimates of VO2max.

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