The effect of high-intensity circuit training on physical fitness.
BACKGROUND
The purpose of this study was to examine the effect of a high-intensity circuit training regimen, using only body weight as resistance, on physical fitness.


METHODS
Ninety-six recreationally active college aged subjects (53 female, 43 male) completed the study. Following baseline testing for height and weight, body composition, aerobic fitness, muscle strength and muscle endurance, subjects were randomly assigned to one of three groups: 7-minute circuit training (CT-7), 14-minute circuit training (CT-14), and a non-training control group (C). Subjects in the CT-7 group (females, N.=17; males, N.=15) were asked to complete a seven minute circuit training workout for eight weeks (three workouts per week). The CT-14 group (females, N.=15; males, N.=13) followed the same protocol as CT-7 through the first four weeks. For the second four weeks they increased exercise time to 14 minutes with the same 7 minute circuit performed twice consecutively. Subjects in group C (females, N.=21; males, N.=15) maintained their normal activity levels throughout the course of the study.


RESULTS
There were no significant differences between the groups for any variables tested prior to the exercise intervention. A repeated measures analysis of variance revealed statistically significant improvements in muscular endurance (push-ups) for both male and female subjects in the CT-7 and CT-14 groups. Males in the two exercising groups also showed improvement in muscular strength while aerobic capacity increased for females in the CT-14 group.


CONCLUSIONS
These results suggest that short duration, high intensity circuit training may improve muscle endurance in moderately fit populations. Slight improvements that are gender specific may also be observed in muscle strength as well as aerobic fitness.
Department of Kinesiology, University of Wisconsin Oshkosh, Oshkosh, WI, USA - schmidtw@uwosh.edu.
Dan
D
Schmidt
Kaz
K
Anderson
Marissa
M
Graff
Victoria
V
Strutz
D000328:Adult; D001823:Body Composition / Q000502:physiology; D001835:Body Weight; D065327:Circuit-Based Exercise; D005260:Female; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D055070:Resistance Training / Q000379:methods; D055815:Young Adult