15 times and the final round nine times.
Between each exercise, subjects climbed a
flight of stairs.
The second WOD selected is one of the most
popular WODs within the CrossFit community.
It’s called Fran and consists of just two exercises:
thrusters (a front squat into a push press with
a barbell) and assisted pull-ups. This WOD was
performed in the same sequence as the first.
Each workout included a five-minute warm-up, a
skill phase, a WOD and a five-minute cool-down
phase. Prior to completing each of the CrossFit
workouts, each subject was required to practice
the selected exercises and then demonstrate to
researchers that they were proficient at each one.
During actual testing, researchers recorded
HR for each subject every minute throughout the
entire workout and RPE was assessed after each
round. Additionally, an overall RPE was taken
at the end of the workout session, while blood
lactate concentration was tested at the beginning
and upon completion of each CrossFit WOD.
Anecdotally, researchers noted that the workouts
seemed very difficult for most of the subjects.
“It didn’t matter their skill or fitness level, and it
didn’t matter how long it took them to complete
the workouts,” says Paige Babiash, M.S., “Each
person was extremely exhausted at the end.”
THE RESULTS
Immediately following both testing sessions,
the researchers crunched the data and plugged
each subject’s HR results into their individual
regression equations to predict V•
O2max for each
WOD session (Table 1).
On average, this study found that caloric
expenditure averaged 20.5 kcal/minute for the
male subjects and 12.3 kcal/min for females.
That said, the amount of time it took each
participant to complete the WODs varied greatly
(some did it in less than 5 minutes, while others
took as long as 20 minutes), a discrepancy that
definitely affected the averages for total number
of calories expended during each workout. Still,
researchers found that males burned an average
of 169.6 calories for workout 1 (completing
the workout in an average time of 8 minutes,
23 seconds) and 112.5 calories for workout
2 (average time: 5:52). Meanwhile females
averaged 117.2 calories for workout 1 (average
time: 9:08) and 63.9 calories for workout 2
(average time: 5:52).
As for heart-rate responses, during the first
round of both CrossFit workouts HRs were
elevated to an average of 90 percent of maximum
heart rate (HRmax), which was maintained
throughout the remainder of the workout (Figure
1). Given that fitness industry guidelines suggest
maintaining a training range of 64 percent to 94
percent of HRmax to improve cardio endurance,