Friday, March 21, 2014

Sprint & Strength Training - A Dynamic Duo For Synergistic Effects: Increased Fitness, Power & Endurance With HIIT + Heavy Lifting in Recreationally Active College Students

Sprinting allowed: Adding two high intensity sprinting interval sessions to a basic weight lifting template entails nothing, but benefits.
Beware, kid! You will become bulky and slow, if you lift weights." I am not quite sure if you've ever heard your high school track and field coach says something like this, but I am pretty sure that there are still coaches out there who would probably doubt the benefits of resistance training for a sprinter. Now, I am not so sure, if the reverse is true for weight lifting coaches, but if it was this would be equally counterproductive. A recent study from the Body Composition and Physical Performance Laboratory (wow, that's the place I would like to work at - at least if we go by the name ;-) at the University of Oklahoma does after all show quite conclusively that "performing concurrent sprint interval and strength training does not attenuate the strength response" and will at the same time lead to significant improvements in aerobic performance measures (Cantrell. 2014).
You can learn more about High Intensity Interval Training at the SuppVersity

Tabata kills ~15kcal/h

HIIT Economy: 30s + 2:1 Rest:Recov.

15% Increase in VO2Max w/ 4x4

Nitrate+Caffeine = HIIT success

More ain't more w/ HIIT

HIIT suboptimal for the obese?
Whether you like it or not. Classic resistance training, and even more so powerlifting, is not exactly a VO2 builder - much contrary to high intensity interval sprints, obviously. Sprints like the ones the 14 recreationally active men completed in the study at hand. The latter were based on a modified Wingate protocol, in the course of which the subjects performed 4-6 bouts of all-out 20-s sprints.
  • the concurrent training group (CT) trained on Monday, Tuesday, Thursday, and Friday with half of the group strength training on Monday and Thursday, while the others performed strength training on Tuesday and Friday, the high intensity sprints were always performed on the other two days
  • the strength training, only, group (ST) completed a general five-min warm-up on a cycle ergometer, before they did back squats, bench presses, leg extensions, leg curls, pull-downs, and shoulder presses in the four to six repetition range (i.e., 85 % 1RM) w/ 2 min rest intervals on two days of the week, only
Hardcore lifters would now probably expect that "hitting it hard" twice a week and "growing"  for the rest of the week would be the optimal strategy to increase athletic performance - way off the mark!
If you take a look at the data in Figure 1 it's plain to see that the "no sprinting", strength only group did not record additional strength gains.
Figure 1: Changes in performance parameters after 6 and 12 weeks (Cantrell. 2014)
Don't ask! No, the 3% difference, which is the difference between +37.8kg (ST) and +33.2kg (CT) is not significant. Unlike the differences in peak and aerobic power, which are huge... ah, I mean, "as significant as" the differences in VO2Max you can marvel in Figure 2.

Figure 2: VO2Max before, during and after the intervention (Cantrell. 2014)
Although VO2max may not be an ideal, it's still one of the best general fitness markers we have. And fitness, in turn is linear correlated with the maximal rate of fatty oxidation in healthy and type II diabetic individuals (Cataldo. 2014), associated with increased glycemic stability in type I diabetics (Singhvi. 2014) and linked to reduced obesity and diabetes risk in the general population.

A low VO2max and correspondingly messed up fitness status, on the other hand, has been linked insulin resistance and fasting hyperglycaemia (Ghouri. 2013), high blood pressure (Emaus. 2011), a loss of cerebral white matter integrity (Marks. 2011), lower blood viscosity and increased cardiovascular disease risk (Lee. 2012).

It is thus not surprising that Lee et al. write in their review of the ,ortality trends in the general population and the importance of cardiorespiratory fitnesst that the latter is "at least as important as the traditional risk factors, and is often more strongly associated with mortality." (Lee. 2010)
Identical gains on the bench, improved power and a fitness bonus - what more can you ask for? Well, I guess I know what you are probably asking for, now. Fat loss! Well, in the study at hand, the researchers didn't observe any changes in body composition.

The latter may be a results of the fact that the participants were already pretty fit (that's also likely to be the reason that their VO2 max suffered, when all the exercise they did was heavy lifting twice a week). Other studies, such as Hakkinen et al. (2003), Glowacki et al. (2004) and Mikkola et al. (2012) did observe improvements in body composition - pretty significant ones, in fact.

Figure 3: Changes in body fat (%) in the Mikkola study (Mikkola. 2012)
So, if an 11% greater increase in endurance capacity (based on time to exhaustion; not shown in any figure), 7% higher increases in peak and 10% greater increases in average power are not enough to motivate you to spend a couple of minutes sprinting along the track / on the treadmill twice a week, the fat loss results of the healthy male subjects in the previously cited study by Mikkola et al. (see Figure 3) could be the incentive you need to finally break out of your comfort = no results zone -  if you wanted to copy this regimen you'd have to add another 30min of steady state cardio before or after your HIIT sessions.
Reference:
  • Cantrell, Gregory S., et al. "Maximal strength, power, and aerobic endurance adaptations to concurrent strength and sprint interval training." European journal of applied physiology (2014): 1-9.
  • Cataldo, Angelo, et al. "Relationship between maximal fat oxidation and oxygen uptake: comparison between type 2 diabetes patients and healthy sedentary subjects." Journal of Biological Research-Bollettino della Società Italiana di Biologia Sperimentale 87.1 (2014).
  • Emaus, Aina, et al. "Blood pressure, cardiorespiratory fitness and body mass: Results from the Tromsø Activity Study." Norsk epidemiologi 20.2 (2011).
  • Ghouri, N., et al. "Lower cardiorespiratory fitness contributes to increased insulin resistance and fasting glycaemia in middle-aged South Asian compared with European men living in the UK." Diabetologia 56.10 (2013): 2238-2249. 
  • Lee, Duck-chul, et al. "Review: Mortality trends in the general population: the importance of cardiorespiratory fitness." Journal of Psychopharmacology 24.4 suppl (2010): 27-35. 
  • Lee, Duck-chul, et al. "Changes in fitness and fatness on the development of cardiovascular disease risk factorshypertension, metabolic syndrome, and hypercholesterolemia." Journal of the American College of Cardiology 59.7 (2012): 665-672.
  • Marks, B. L., et al. "Aerobic fitness and obesity: relationship to cerebral white matter integrity in the brain of active and sedentary older adults." British journal of sports medicine 45.15 (2011): 1208-1215.
  • Mikkola, J., et al. "Neuromuscular and cardiovascular adaptations during concurrent strength and endurance training in untrained men." International journal of sports medicine 33.09 (2012): 702-710.
  • Singhvi, Ajay, et al. "Aerobic Fitness and Glycemic Variability in Adolescents with Type 1 Diabetes." Endocrine Practice (2014): 1-18.