Circuit Weight Training Improves VO2max
Do you have a hard time finding time to exercise both cardiorespiratory fitness and musculoskeletal health? Then give circuit weight training a try.
Here are brief descriptions of three CWT programs—from actual training studies—that were shown to significantly improve VO2max. VO2 max is maximum oxygen consumption and the higher it is, the better your cardiovascular heath and all cause mortality will be. All three studies compared circuit training with another type of activity and a non-exercise control.
CWT Study #1
Gettman, Ward & Hagan (1982) recruited 77 healthy men and women (average age 36) for this 12-week study. After extensive baseline screening for cardiovascular risk factors, participants were randomly assigned to three groups: circuit weight training (CWT), concurrent training (running and CWT), and a non-exercising control group. The CWT group trained 3 days a week during the study period using a circuit of 10 exercises that alternated between upper and lower body: squat, shoulder press, knee flexion, bench press, leg press, elbow flexion, back hyperextension, triceps extension, abdominal sit up and vertical chest fly.
Participants performed all exercises at 40% of a 1-repetition maximum (measured every 2 weeks), completing 12–15 repetitions in 30-second sets, with 15 seconds of rest between exercises. A total of three circuits were completed during each session. In 36 sessions, the CWT group members increased their VO2max 12%–13% and made significant improvements in lower- and upper-body strength.
CWT Study #2
In a 3-month study, Piras et al. (2015) investigated the effects of circuit weight training versus high intensity interval training. The CWT group comprised 10 healthy male and female participants (average age 24) who were recreationally active and free of any musculoskeletal and cardiorespiratory disease.
The CWT program consisted of six exercises performed in this rotational order: chest press, leg extension, latissimus dorsi pulldown, leg curl, shoulder press and seated heel raise. Participants performed 15 repetitions of each exercise at an intensity of 55%–60% of the 1-RM for that exercise. Subjects each wore a heart rate monitor and completed the workouts at 60%–80% of maximal heart rate. After performing all six exercises—with no rest between them—participants rested 1 minute and then repeated the circuit. Each session consisted of four circuits, and there were 30 sessions (on nonconsecutive days) in the 3-month period.
The CWT group showed an improvement in maximal aerobic capacity of 8%.
CWT Study #3
In another 12-week study, Kaikkonen et al. (2000) recruited 90 (male = 45, female = 45) middle-age, sedentary but otherwise healthy adults and randomly assigned them to endurance training, CWT or a non-exercising CWT participants performed three rounds of 10 exercises on air resistance machines, working for 40 seconds and then resting for 20 seconds. Intensity was fixed at 20% of 1-RM, with the number of repetitions performed at each station increasing throughout the study. Circuit exercises were leg extension, leg curl, abdomen curl-up, back extension, leg abduction, leg adduction, body twist right, body twist left, pushup and a pulldown exercise. Each participant wore a heart rate monitor and completed the workouts at 70%–80% of maximal heart rate.
After 12 weeks of training, the CWT group demonstrated an improvement of 11% in VO2max.
Body-Weight Circuit Training
To see if body-weight-only CWT could improve VO2max, Myers et al. (2015) recruited 34 sedentary but otherwise healthy college-age females and randomly assigned them to combined (traditional resistance training and endurance exercise) (n = 17) or CWT (n = 17) training. The CWT participants exercised on 3 nonconsecutive days a week for 5 weeks, with just their body weight for external resistance.
Researchers provided repetition goals for each exercise. Participants were instructed to complete the circuit as many times as possible in a 30-minute period, with minimal rest. After 15 sessions, the participants in the CWT group had increased their VO2peak by 11%—a significant improvement. A key message from this study is that 90 minutes of body-weight CWT per week improves maximal aerobic capacity.
A Nontraditional Approach
Are there any unique variations of traditional resistance training that also improve VO2max? Haennel et al. (1989) recruited 32 middle-age males with below-average aerobic fitness and randomly assigned them to four groups: non-exercising control, endurance training and two resistance training groups. Participants trained 3 days a week for 9 weeks, with each workout lasting less than 30 minutes.
Unlike in circuit training, where enthusiasts rotate sequentially from station to station, in this study participants completed 3 sets of each exercise and then moved to the next station, following the traditional resistance training model. The exercises performed in each workout included the following movement patterns: knee extension, knee flexion, leg press, elbow extension, elbow flexion, chest press, shoulder extension, shoulder flexion and plantar flexion. For each exercise station, participants did 3 consecutive sets of the exercise, performing 20 seconds of work (for each set) followed by 20 seconds of rest. After the third set of an exercise, there was an 80-second rest before the next exercise.
One resistance training group performed the maximal number of repetitions (MAXrep) for each 20-second set. The second resistance training group performed 70%–85% of the maximum number of repetitions (SUBrep). The intensity settings on the hydraulic equipment were similar for the MAXrep and SUBrep training groups on all exercises. As intended, the SUBrep group performed about 14 repetitions per set, while the MAXrep group performed about 16 repetitions per set.
During 9 weeks of training, the SUBrep group increased their VO2max by 12.5% and the MAXrep group increased their VO2max by 11.3%. Uniquely, this nontraditional “rapid fire” approach to training elicited very favorable results for improving VO2max for both these groups.
A major take-away of this article is that people with higher VO2max capacities have more favorable cardio metabolic health and lower risk for cardiovascular diseases. The evidence-based workouts summarized in this article appreciably substantiate that creatively designed, time-efficient resistance training workouts can deliver excellent cardiovascular results. Get on it!
For more information on circuit weight training and cardio health, contract Maurie Cofman, CMES, CES, TBMM-CES, Personal Trainer, Certified Medical Exercise Specialist, Health Coach and Corrective Exercise Specialist in the St. Louis, Brentwood, and Clayton, MO area.
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