Insulin Sensitivity After Maximal And Endurance Resistance Training
A review of:
Hansen E, Landstad BJ, Gundersen KT, Torjesen PA, Svebak S., Insulin Sensitivity After Maximal And Endurance Resistance Training, J Strength Cond Res. 2012 Feb;26(2):327-34. [http://www.ncbi.nlm.nih.gov/pubmed/22240549]
As much as I like to lift weights, watch sport and chase girls, I’m truly a nerd at heart, and for a nerd (at heart), the pinnacle of nerdiness is research.
Actually, wait a minute, the pinnacle of nerdiness is role playing games. Research is the the pinnacle of scientific information. Phew! I’m not a nerd after all – not that there’s anything wrong with that [this is actually the second time I've used that Seinfeld reference in a post, props to anyone who can remember the first].
Whether it’s for nerds or scientists (the two are mutually exclusive), research, for all it’s flaws, is the best tool we have for gaining knowledge, and good trainers (like me), try as much as they can, to read research that both supports and refutes what they are doing.
My masters supervisor sent me this study a few weeks back, but it wasn’t until now that I actually got a chance to look at it.
Why You Should Read On
I get that most people out there couldn’t give a shit about research. What I find interesting (and funny, though not in in a haha way) is that many of these same people will make countless decisions daily, based on the mainstream media’s description of research.
I’m pretty sure everyone has heard someone make statements similar to these: “I’m taking my omega-3s”. “Fructose is bad”. “Don’t eat trans fats”.
Generally they are just repeating what they read in a newspaper. Instead, they should be repeating what they read here, because I’m going to do a more thorough job of dissecting in the primary source of information, without the bias of having to please advertisers at the same time.
What The Study Is About
The study wanted to compare the effect of maximal resistance training to that of endurance resistance training on a host of markers relative to glucose tolerance and insulin sensitivity.
I found this really interesting, because, it took a group of older (but not too old) adults (mean age was 47 across both groups) that were overweight and had signs of impaired glucose tolerance.
Impaired glucose tolerance basically means that these folk don’t handle sugar too well, which is considered a pre-diabetic state, generally caused by lifestyle factors, although there is a genetic component to it too.
In other words, if they continued living as they were, it was likely they would contract type II diabetes, and the wonderful array of complications that it brings with it – in short, not good.
What was good, is that these people, had some awareness about their situation and volunteered to participate in a study.
What Was Tested
These markers were:
- Fasting glucose levels: how much glucose is in the blood stream after fasting for 8-10 hours
- 2 hour glucose levels: how much glucose is in the blood stream 2 hours after exposure to a glucose drink (this has a GI of 100, the highest possible, healthy people will clear the glucose pretty quickly, those with impaired glucose tolerance will not).
- Insulin levels: these test the levels of insulin in the blood. Ideally, insulin would be in the normal range, as would glucose. If insulin was high, but glucose was normal, then there might be some insulin resistance, which means the body has to produce more insulin to compensate (this is why it is better to get lean before you get big, as your insulin sensitivity improves, meaning your nutrient partitioning – the amount that goes to muscles as opposed to storage – is better). There are other scenarios (insufficient insulin, hypoglycaemia) but those are the main two points I’m concerned with.
- C-peptide: this is a protein that the body produces along with insulin. It helps distinguish between endogenous and exogenous insulin, as well as helps confirm things like insulin resistance.
What Was Done
The title mentions maximal and endurance resistance training. So I best get to defining these terms before I go on, lest you get confused and click away.
One group was assigned to Maximal Resistance Training (MRT). This is your beast mode training – lifting heavy ass stuff for relatively few reps.
In the study they used a reverse pyramid style training; heaviest set first, then dropped the weight for the subsequent sets to maintain the workload. They used sets of 3-4 reps in the 60-85% range, for 5 total sets (they called set bouts, and then the group of bouts sets, which left me confused as to whether it may have been 1 extended set done in rest pause fashion – this lead to a little confusion on my part).
As an aside. Martin Berkhan of Leangains fame is a big proponent of reverse pyramid training.
The exercise selection wasn’t the greatest, but hey, they are scientists, not trainers; still, I’d like to see them recruit someone from the exercise science department to design the programs instead of going from a (crappy) text book.
The other group was the Endurance Resistance Training (ERT). They performed 8 exercises for 3 sets of 12-15 repetitions, at 40-65% of 1RM with 30-60s rest between sets. Pretty similar to the type of program your average gym rat does and makes no progress on after newbie gains.
Both programs were done for 4 months. The MRT group went first whilst the ERT acted as a control. Then the ERT group went using their own data for a control.
What Was Found (Results)
There was no change in fasting glucose levels from pre to post-intervention. This was not surprising (according to the researchers), as these levels were not impaired.
The 2-hour glucose test did however demonstrate improvements after MRT, suggesting an improvement to glucose tolerance. MRT also reduced C-peptide levels.
The only parameter ERT had a significant effect on were fasting insulin levels. These were lowered, which is a good thing.
ERT was also shown to improve insulin resistance, insulin sensitivity and beta cell function (the cells in the pancreas that produce insulin) whilst the MRT group only displayed significant improvements in insulin resistance.
It must be noted though, that neither group showed any impairments in insulin resistance, sensitivity and beta cell function prior to the interventions. So it may not necessarily hold true for those with impairments.
What This Means To You
This was probably really boring for you, so if you’ve just scrolled down to this part, I forgive you.
What this study suggests, is that for prevention of type 2 diabetes, your best bet is a combination of MRT and ERT.
Practically, it means don’t spend all your time training one spectrum of the repetition scale if you are training for general health and fitness. Train some lifts heavy, some moderate, and some lighter. Kind of like what I’ve previously suggested.
And that’s the thing with research. Often it confirms what we are already doing. But that doesn’t mean it is useless. On the contrary, it can help us work out why something works in order to better it, which after all, is the name of the game, getting better.