That is a video of Rif and his wife towards the end of a workout aimed at building the VO2 max (the aerobic base or, technically, the maximum capacity to transport and utilize oxygen during incremental exercise). They are working 15 seconds on then 15 seconds off. You can see it is hard work.
Ok now compare that to a study that I just came across:
Cardiorespiratory Responses to Kettlebell™ Training Exercise: 1162 Board #17 2:00
PM - 3:30 PM
[D-20: Free Communication/Poster - Cardiac: Acute Exercise or Exercise Training: THURSDAY, JUNE 2,2005 2:00 PM - 5:00 PM ROOM: Ryman C2]
Bishop, Emmett; Collins, Mitchell A. FACSM; Lanier, Angela B. Kennesaw State University, Kennesaw, GA. (Sponsor: Mitchell A. Collins, FACSM) (E. Bishop, Dragon Door Research Grant Recipient.)
Although resistance training using Kettlebells™ is not new, the popularity of Russian Kettlebell™ training has recently grown in the U.S. due to promotion by Pavel Tsatsouline. However, at the present time there appears to be little scientific literature on Kettlebell™ exercise.
Therefore, the purpose of this study was to describe the cardiorespiratory responses to a typical 30-minute bout of Kettlebell™ training.
Five males and five females (24-58 yrs) were recruited to participate in the study. Each performed five sets of ten repetitions for three Kettlebell™ exercises each separated by 1 minute of rest. The exercises consisted two-arm swings, one-arm snatches (half performed with each arm), and one-arm clean and presses (using right and left arms). The females used a 4 or 8 kg Kettlebell™ based on strength and the males used an 8, 12, or 16 kg Kettlebell™. The cardiorespiratory responses to the exercise were measured using a Parvo Medics TrueMax™ 2400 metabolic system. The data were analyzed using simple descriptive statistics.
The cardiorespiratory responses varied greatly among the subjects and were related to the size Kettlebell™ each used. After the intial adjustment to exercise, ventilation (BTPS) ranged from about 24-39 L/min. This corresponded to tidal volumes and respiratory rates from 0.9-1.4 L/br and 24-41 br/min. Oxygen consumption values were from 0.65-1.28 L/min or 9.7- 18.0 ml/kg/min. Respiratory exchange ratios were from 0.88-1.07 with values typically below 1.0. Exercise heart rates were found to be between 101-143 bts/min and mean (±SEM) blood lactates following exercise were 4.3±1.8 mmol/L.
The cardiorespiratory responses to Kettlebell™ exercise were relatively low. The values were less than reported for traditional weight training exercise performed at 40% of one-repetition maximum. The low response found for Kettlebell™ exercise was probably due to the incorporation of momentum in Kettlebell™ training along with the size of Kettlebell™ used by the subjects.
So the scientists say that cardiorespiratory responses to Kettlebell™ exercise were relatively low. ?! (I came across the study here BTW). You read that and you think that kettlebells are crap! Rubbish for cardio work! eh? I bet Dragon Door research wanted their grant back for this one!
I do not want to be an apologist for kettlebells (and when did that word become a trademark?) but there are so many problems with this study. What where they comparing this training to? Why did they pick this particular protocol? - if you want to stress cardiorespiratory response then you wouldn't train like they did you need to stress the right energy pathways and the protocol that they chose is not doing that. Rif's protocol will hit the right systems, doing 5x10 with a minute rest between sets will not.
The conclusions that they give are dodgy too. Momentum has nothing to do with it! Look at that video again and you will note that the momentum doesn't seem to limit the effects!
Unfortunately you cannot go much further with this study since it is only a poster at a conference rather than a published peer reviewed article, but it is instructive that you need to think critically about the science. Just because I put up an abstract here doesn't mean you should accept it as gospel. Think about it a bit. Be critical.