|Image 1: The squat - as intense as it is, it is no replacement for "aerobics"; more on squatting in the EMG Series|
And more generally, i.e. in view of the aerobic effect and energy expenditure in the course of a complete strength training session, it would be interesting to know, ...
- how much total energy you were expending while benching,
squatting, rowing and co., and
- what the relation of aerobic to anaerobic energy expenditure was like during heavy resistance training.
As their measuring tool of choice, the scientists selected the oxygen deficit method (AOD), where the anaerobic contribution to the overall energy expenditure is estimated by linear extrapolation of the VO2 at supra-maximal intensities and the AOD is then calculated by subtracting the cumulative oxygen uptake (VO2Ac) from the estimated energy demand. As the scientists point out, thus...
[...] the VO2Ac represents the portion of energy obtained by aerobic processes and the AOD represents the portion of energy obtained by anaerobic processes [so that] their sum equals the total VO2 during exercise.The subjects in the Vianna study were 14 male resistance trainees (26.6 ± 5.4 years, 1.77 ± 0.07 m height, 80.1 ± 11.4 kg body mass and 11.2 ± 4.6 % body fat) with at least one year of training experience on a protocol with three or more training sessions per week. After height, weight and several skin fold measures (chest, mid-axillary, tricipital, sub scapular, abdominal, supra iliac, and thigh) had been taken, the individual 1RM max for bench press, half squat, lat pull down and triceps extension were assessed. Afterwards, the scientists measured the VO2 for each of the four exercises at 12% and 20% of the previously established 1RMmax. The same procedure was repeated 48+h later at 16% and 21% of the individual 1RM max. Eventually (again 48+h rest), the subjects had to perform their bench presses, half-squats, lat pull downs and triceps extension at 80% of their 1RM. The gas the subjects expired during those sessions was collected and recorded by an open air circuit analyzer - you can see part of the results plotted in figure 1.
|Figure 1: VO2Ac (ml/kg) and accumulated oxygen deficit (AOD; ml/kg) at 80% 1-RM for bench press, half squat, triceps extension and lat pull down (data adopted from Vianna. 2011).|
|Figure 2: Relative contribution of aerobic and anaerobic metabolism to overall energy costs of bench press, half squat, triceps extension and lat pull down at 80% of the individual 1RM (data adopted from Vianna. 2011).|
|Figure 3: Total energy demand (ml/kg) of bench press, half squat, triceps extension and lat pull down at 80% of the individual 1RM (data adopted from Vianna. 2011).|
The "king of all exercises" is in fact so energetically demanding that one set of squats at 80% of your 1RM max will still expend ~9% more energy than a workout consisting of bench presses, triceps extensions and lat pull downs! Nevertheless, while it cannot be excluded that squatting will indirectly improve your aerobic exercise performance, as well, in and out of itself, none of the tested exercises is suitable to replace what is commonly understood to be "aerobic" or "cardio training" - but hey, in view of what I have posted about the effects of HIIT training, lately, doing (regular) "cardio" training may be obsolete, anyways ;-)