Eight HIIT Sessions on the Rowing Ergometer Cut Body Fat, Increase Adiponectin, VO2Max & Performance in National Level Rowers - Workmatched Classic 'Cardio' Does Nada

If you have hitherto ignored my previous advice (e.g. "Choosing Your Workout Style") to give the rowing machines a try, maybe the study at hand will rise your interest. Give it a try. It's an awesome whole body workout and highly effective, even if you just do 20min of steady state after lifting weights.
Yesterday you've learned that even the most idio... ah, I mean unconventional - not to say "experimental" in the literal sense - one-legged leg training routine is more likely to get you those six-pack abs, of which everyone appears to believe that it was a natural sign of outstanding health and a thing everybody must have (just like the new iPhone, you know ;-), than a bazillion of sit-ups. Today, you will see that a somewhat less "experimental" training regimen will not have you reach your goal faster and more efficiently, it will also have the welcome "side effect" of making you healthier and improving your conditioning. And you know what's the best about all that? It does not only work for sedentary baby-boomer, but also for highly trained athletes. 5 male and 2 female19(± 1.2)-year-old junior state and national level rowers from the Tasmanian Rowing Team (height: 1.77 ± 0.10 m, body mass: 74.0 ± 10.7 kg, body fat: 17.1%, VO2max 62.1 ± 7.0 mL·kg/min), to be precise (Shing. 2012).

Healthier, leaner, fitter - that's a HITTer ;-)

To evaluate the influence of two different training regimen, namely the traditional steady training (SST/LISS) on a rowing ergometer (a piece of equipment of which the regulars among you already know that I highly suggest you incorporate it into whatever cardio routine you may be doing), or a high intensity interval training (HIIT) variety of the latter the researchers from the School of Human Life Sciences at the University of Tasmania in Launceston, Australia put their participants, the aforementioned young national rowers, on two different workout protocols with matched cumulative energy expenditures (my emphases in Shing. 2012):
  • SST: "The traditional training program involved rowers completing two ergometer sessions per week; one with a duration of 35 minutes and the other 40 minutes. [...] The intensity of each session
    was relatively low and more aerobic in nature when compared to the interval training protocol. The intensity of the traditional ergometer sessions was set to power outputs that corresponded to blood lactate concentrations of 2 and 3 mmol/l determined from the incremental exercise test."
  • HIIT: "The interval training sessions consisted of eight 2.5 minute intervals at 90% of mean four-minute maximal power achieved during the incremental exercise test. Recovery between each interval was at an intensity of 40% of mean four-minute maximal power and the recovery duration was until heart rate returned to 70% of maximum heart rate, up to a maximum of five minutes."
The 2x four week experimental period (remember: we are dealing with a cross-over design, where all subjects participate in both protocols in random order) involved the incorporation of two ergometer sessions per week. Since all participants were part of the same squad the rest of their training regimen was identical, so that confounding factors - at least as far as the training is concerned - can be ruled out.

Body composition and adiponectin took a HIIT - a highly beneficial one that is ;-)

Performance tests were done and body fat mass (DXA), as well as a general blood profile and adiponectin values were taken at baseline and the end of both 4-week periods. Moreover, all participants had to keep a detailed training and diet log, so that the scientists could make absolutely sure that non of the effects they observed were due to unexpected changes in either activity levels or dietary habits.

Any potential influence of the randomized order, i.e. whether the rowers performed the classic training first and the HIIT sessions 2nd or vice versa was ruled out by statistical means before the scientists eventually analyzed their data sets and got the following results:
Figure 1: adiponectin levels before (pre) and after the respective workout at the beginning and end of the respective 4-week training period and body fat levels before and after 4 weeks of steady state (SST) or high intensity interval training (HIIT) in national level rowers (Shing. 2012)
I must admit, the changes are not earth-shattering, but there are changes - beneficial ones that is  - and they are statistically significant despite the small number of participants, and the fact that the subjects were already highly trained individuals and - I figure this may be the most convincing argument not to discard this effects - participated in no more than a total of only 8 HIIT sessions.

Bottom line: I guess, you could certainly argue that the novelty of the training stimulus was part of the reason, the HIIT regimen had so beneficial effects on the fitness, body composition and even the adiponectin levels of these already highly trained rowers (Adiponectin? That's the "new leptin", which promotes insulin sensitivity and exerts profound anti-inflammatory effects); but does this take away from the efficacy of this 4x2.5 min @90% max. + 5min active rest high intensity interval training regimen? I don't think so.

Click here to learn more about the "Iranian HIIT Solution" a minimalist program with maximal results
There is nonetheless one thing I want to add before I close the SuppVersity doors for today. The 4x2.5 minute protocol is certainly appropriate for trained athletes; in fact, previous studies even suggest that it requires those long(er) intervals in order to elicit gains in VO2max in highly trained (endurance) athletes (e.g. Franch. 1998; Laursen. 2002). The initially mentioned sedentary baby-boomer - obese or not - may however be better off, if they follows a different regimen, such as the one I outlined in the "Iranian HIIT Solution" (see image on the right) and incorporate that in a three-day split (e.g. A, B, hypertrophy, C strength) or a two-day full body circuit training.

The main message here is that starting out "low" (in terms of both volume and intensity) is not just possible, it's even advisable, so that there is still enough room to do more, and/or preferably up the intensity. I know I have been telling you that before, but I feel it's worth stating again: Real cardio training, i.e. the type of training that strengthens the cardiovascular system is progressive. If you do the same thing day in and day out the best you can hope for is to keep the status quo. Remember that before you start out way too high (esp. on the volume side of things) and either bunk directly, or end up without any room to make progress.

  • Franch J, Madsen K, Djurhuus MS, et al. Improved running economy following intensified training correlates with re-duced ventilatory demands. Med Sci Sports Exerc 1998; 30: 1250-6.
  • Laursen PB, Jenkins DG. The scientific basis for high-intensity interval training: optimising training programmes and maximising performance in highly trained endurance athletes. Sports Med. 2002;32(1):53-73.
  • Shing CM, Webb JJ, Driller MW, Williams AD, Fell JW. Circulating Adiponectin Concentration AND BODY composition ARE Altered in Response to High-Intensity Interval Training. J Strength Cond Res. 2012 Dec 4.
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