Metabolic and Cardiovascular Response to the CrossFit Workout ‘Cindy’

Metabolic and Cardiovascular Response to the CrossFit workout ’CINDY’. CrossFit is a fast growing sport of fitness that not only serves as a form of competition but as a form of general exercise training. Little is known about this young conditioning program and a better understanding of the metabolic and cardiovascular demands is needed. PURPOSE: It is the purpose of this study is to examine the acute metabolic and cardiovascular demands of a named CrossFit workout using semi- to well-trained subjects. METHODS: 7 men and 2 women (mean age = 27.2 ± 9.6) who have trained in CrossFit for at least 3 months participated in the study. Each subject performed a graded exercise test on a treadmill to determine maximal oxygen consumption (VO2max). All subjects performed the named CrossFit workout called ‘CINDY’, which consisted of as many rounds possible of 5 pull-ups, 10 push-ups, and 15 air squats in 20-minutes. A portable metabolic analyzer was used to record volume of oxygen consumption (VO2) and rate of caloric expenditure (kcals.min-1).  The subjects also wore a portable heart rate (HR) monitor. Means ± SD were determined for the following variables: VO2, %VO2max, HR, %HRmax, kcals.min-1, METs and total kcals. RESULTS: The results demonstrated that ‘CINDY’ resulted in average VO2 of 33.3 ± 5.5 ml.kg-1.min-1, which corresponded to 63.8 ± 12.3 % VO2max. In addition, the workout elicited a heart rate of 170.8 ± 13.5 beats.min-1. Furthermore, the subjects expended 13 ± 2.9 kcals.min-1, corresponding with a total caloric expenditure 260.6 ± 59.3 kcals. The average MET level was 9.5 ± 1.5. CONCLUSION: The findings of this study suggest that ‘CINDY’ could be classified as “vigorous intensity” based on established American College of Sports Medicine HRmax guidelines i.e., between 76 - 96 % of HRmax, while VO2max parameters where classified as “moderate intensity” i.e., between 46 to 64% of VO2max.  Further investigation is needed to compare the metabolic response of other popular CrossFit workouts.