Saturday, February 6, 2010

Possible role for Heart Rate Monitors in Kettlebell Strength Training or Total Eclipse of the Heart

Heart rate monitors (HRM) have become a familiar accoutrement of the triathlete/running set for some time. Athletes use these devices to tune their endurance efforts for maximal aerobic threshold work and optimal effort to recovery ratios. Sounds like that makes sense.

In the Iron Gym, HRM's are far less regularly seen. After all, lifting weights is lifting weights. Where the heck would a Heart Rate Monitor come into play?

Lately, i've been exploring this question: to see if HRMs might also help tune effort and recovery for optimal training. This post isn't the ultimate finding of that exploration, but a description of how this exploration is being set up, and especially the rationale for it.

Maybe before addressing that one, it would be useful to take a step back and say why/when a heart rate monitor at all? And THEN take a look at an approach for exploring its use in weights work. (if you know all this stuff about R-R distances, how/what HRM's monitor and calculate, just skip scroll to re-enter RTK for the resistance application...)

What do we actually "monitor"?
We are electric plastic people. We pulse. Electrically. And because of that, those pulses - electrical impulses moving through the muscle of the heart in this case, but like any electrical activity, can be detected- in this case via conductors on the skin. Once the pulse is detected, a signal that represents the pulse can be transmitted and communicated to a device that does so much more now that just count the beats, but beat counting is no small thing.

R-R distances

What we know from this measure.
In a way, all we know explicitly from a heart rate monitor is that there is a pulse. The computer in the HRM translates this into a frequency of beats per minute, relatively accurately - close enough for most healthy people's purposes, and especially the higher end models like the Suunto T6C, you'll see used in research papers as the measuring device in studies. These heart rate monitors track the specific measurements between the big peeks in the heart rate pulse - the R to R distance (seen above) - we'll come back to this and why being able to note the differences in distances is so valuable for training.

The rather impressive thing is that, from the miracle of statistics, we can use readily knowable values like age, gender, height, weight and max heart rate to figure out all sorts of things about energy systems being taxed, our capacity to use oxygen, and more recently, based on load and effort, a more clear picture of how long we'll need to recover from the type of work we've done, so that we can specifically focus our training on making the whole of us get stronger. All that from the simple lub dub moving the blood, pushing the o2, saying we're alive.

The first thing to measure from the measure: Max Heart Rate
In order to take best advantage of a heart rate monitor, a key value to get is the Maximum Heart Rate. Max Heart Rate (MaxHR) is pretty much the greatest number of beats one's heart is capable of generating in a minute. It's age, gender and ethnicity effected. But that said, it's also individual as well as being somewhat device-specific. Consequently, Max Heart Rate is a pretty important value to get right because so many other measures take this limit as a critical part of the calculations. There are a bunch of ways to get at that, some more than others.

Statistical Approaches. Max heart rate is often simply calculated based on equations derived from stats of various populations. These equations (many examples here) often provide an ok ball park but LOADS of people have heart rates that are higher or lower than the calculation, so i don't want to give the equation.

Maximal or Near Maximal Tests. I'd like to suggest you get it measured. There are many ways to self test or get a Real Test. If your doc has cleared you to work out, check if you can do a MaxHR test; if not there are ways to do partial max exertion tests to get a good enough approx till you're more fit.

Device Sorta Specific. Also, quick note, besides the fact that there are a bunch of ways to figure out your max heart rate, they vary by device you're using. I can crank out a good five beats more on an evil elliptical than i can on a bike, and the bike's higher than the rower, and the rower is higher than kettlebells. THis is pretty normal based on amount of big muscles used in any given activity.

The First Use of MaxHR: Zones of the Heart
The next thing that comes up in heart rate monitor use is figuring out whether we're staying aerobic or going anaerobic in our efforts - and how long in either zone. The border crossing from aerobic to anaerobic is pretty much 85% max. It is not unusual, howerver, to have multiple "zones" defined in the aerobic area as well to indicate at least a kind of degree of effort.

Load and Recovery. This sense of effort can be important for planning effort levels, effect on the central nervous system (CNS) and recovery. For instance, not every day would one want to work for an hour at the anaerobic threshold, or only do cardio work at 60% of effort if one is a healthy, mobile person. So checking what zone one has been training in may help with understanding if one has been working sufficiently to promote a desired adaptation.

Why Else is this Zoning important? Energy systems.
Before going anaerobic, we're primarily using fat for fuel. Good-o right? And fat is generally converted to fuel in the presence of oxygen. Breath in and out. Cook a calorie. Yodelayheehoo. SO aerobic, which means in the presence of oxygen, is a good thing. Sleeping is aerobic. Running so that you can carry on a conversation is aerobic. Quite a range.

But (a) oxidising a gram of fat gives off a hefty 9kcals of energy and that's grand, because fat oxidation is not what you'd call a fast process. So relatively speaking only a certain amount of muscle can be turned on at once since there's only so much fuel available.

When we pump up the demand - to sprint, or lift heavy - when we have to recruit more muscle to get that extra power, we need a burst of fuel for that. And a burst is about all we'll get from the phosphate system (anaerobic) which can do a good burst but only for a moment (well, 30sec), and then there's sugar in the muscle and bloodstream, if it's there to be had - it can only do so much more - for maybe a minute or so. Imagine a 400 yard dash. And then it's gone.

The goal in most endurance training is to be able to raise the threshold at which we can take advantage of the plentiful fuel resources in the O2/fat equation. So you'll see folks with their heart rate monitors working on Time - being able just to work longer at a given aerobic heart level. So they're watching their heart rate to stay in that "i can still talk while i'm running mode"

And then there's the pushing the envelop - the anaerobic/aerobic envelop. Here, the goal is to tax the upper end of the system - to push into the anaerobic for brief or longer periods with recovery spurts (to rebuild those rarer energy system resources) back in the aerobic world to drive up the aerobic threshold.

The more power we can generate with Fat/O2 the better.

Total Eclipse of the Heart Rate Monitor: Cardio. The above more or less explains the fundamental uses (not all, but the basics) of HRM's for endurance work generally. There's a lot more to current heart rate training and high end heart rate monitors than what i've just described. Current approaches calculate EPOC, heart rate variability, vo2 capacity, and something called "training effect" that is very cool to be able to see to what degree one's workout really *is* pushing one's training to cause an adaptation, or just keep one at the same level.

Shifting to Resistance Training
How does this monitoring apply to resistance training? i bet there's lots of ways, but i'm afraid here it gets a bit personal. Indeed, it's rather a challenge to find any papers that have a person using a heart rate monitor throughout a training session, rather at most, before and after the session. Why is this? Maybe it's because using a HRM in resistance training is stupid; or maybe it just hasn't been looked at. So why am i? Where am i?

I'm using an HRM to test
  • energy system taxed,
  • overall work of a workout,
  • effective recovery between sets
My biggest take away from the experiment so far, is that my workouts have been seemingly less taxing or effortful than i am apparently readily capable of training. The result has meant that i have added more volume to my workouts - without compromising my recovery. In the following i'll try to unpack how i've come to that finding.

RE-enter the Return of the Kettlebell
I have been following Return of the Kettlebell since the fall - this has light, medium and heavy days in order to allow suitable amounts of volume, recovery and load to promote an hypertrophic adaptation. Part of the protocol is progressive increase in load over time, but the way to progress load is first to get the speed up for a set completion, and time down between (and within) the max number of reps & sets ( 5 ladders of 5 rungs each) before moving onto a new weight.

In doing this work, i became curious as my times were going down, what kind of work i was doing - what kind of effort i was putting in - how much of the work was happening especially on heavy days in the aerobic zone as opposed to pushing into the anaerobic - where power is supposed to take place.

Hypertrophy vs Power. Part of the challenge in this protocol is that it's not a power protocol, per se, but an hypertrophy protocol. That means it's more reps with less recovery than power - much closer to endurance than power (as best we understand hypertrophy). So, really, most work *would* be in the aerobic zone - though perhaps towards the higher end of the MaxHR. At least that's how i've been looking at it.

Ramping Up the Heart: Warm ups for Work, Revisisted
This may be stating the obvious, so forgive me, but even if working quite hard, it can take time to get the heart rate up to working level. By working level, i simply mean where one is working at a level of effort to induce an effect on work capacity (O2 capacity) would take place. This is one reason perhaps to consider doing a warm up on a bike for ten minutes.

Why bother? why care? Well personally, i haven't. I've used my initial sets in RTK to warm up. What that means is that by the time the workout is done 20 or 30 mins later - only half to a third of that effort has been working my heart outside of MAINTAINING my current level of endurance strength, and letting me advance it's training.

Now, there's a caveat here: not EVERY workout ever should be or needs to be in that higher region of the heart. But looking at my heart rate let me know that i was not taking advantage of the training opportunities i could be just by doing some preliminary warming up. I had sauce left for more VOLUME, and volume is king.

This kind of thinking for a warm up is not the norm to me, but it's been revelatory. Indeed, as if to underline this, Coach Hauer the other day, looking at some vid of my snatch work, commented that my second long sets were consistently stronger than the first ones (i didn't warm up before these sets). Second sets are definitely the ones pushing into training effect rather than maintenance when i look at the logs. Hmm. And they seem stronger? Hmm. "So warm up before you do your snatch test?" was the suggestion. Just warm up.

The logs i'm looking at are of my heart rates at points throughout the sets.
The above image for example is RTK medium day, five sets of five ladders, concluding with two sets of double kb squats, then, seeing i had more time/energy, finishing with the 5*20s double swings.

What the lower panel shows is a combined EPOC (the line going up) and calculated cumulative training effect (the colored bands) of the workout. Training effect here - is how long one might need for recovery before doing another workout of this intensity. This one was a TE of 3.1 - meaning that (a) the workout was causing more than a maintenance of current training, but was pushing slightly into the realm of causing an adpatation/improvement. That also means however, that there's a recommended 1-3 days break before doing this kind of workout again. We'll look at how to get more precise below.

Inter-Set Recovery
Another thing i've been checking with an HRM is where the reasonable recovery is between sets. Now on the one hand, one usually "just feels" when it's appropriate to get back, or one takes recommendations of how long to pause based on the type of effort one is performing.

Two things happen in RTK: pavel initially recommends two minutes between ladders, but he also suggests trying to get time between reps in sets down with the goal of seeing how quickly one can get the time down for the workout to use as a gate for moving up to the next weight.

I have recently been using an HRM to see if the way i "feel" about readiness to start the next set is mapped at all to a given heart rate level - if i'm trying to keep my heart working. What i've learned is that i can still perform well without pooping out by the end of the set if i start a little less recovery than i had been wont to give myself. In other words, when i've pushed myself to start say ten beats higher than my normal "feel" it's been ok; it hasn't cost me performance of good reps. In other words, the HRM has let me check where to reset "feel" to start again to push my training adaptation a bit more without pushing too far and too hard.

Right now, using an HRM in resistance is mainly a way for me to keep track of the fact that
a) i did my workout
b) i put some good effort into it
c) give me a visual comparison of the same workouts within a given block or blocks over time

and to use that to see patterns of adaptation or not to see what else i might want to do with my training.

For instance it was checking my total training effect (a measure of heart rate variability to determine fatigue and time needed for recovery) from RTK that let me know i was probably ok to do the snatch practice work i've been doing on the days between RTK (lots of snatching in prep for the snatch re-test at RKC II end of feb). That's been great to have.

Calories and High Heart
I also admit that i like to see how many calories a workout burns - relative to the given accuracy of the calculations on the HRM. For instance, 10 mins of swings at the end of an RTK session burns as many calories as 20+ minutes of pressing. Wow. so that's just another bit of motivation to say ya do the few extra swings - get a few extra calories and a bit more effort on the heart too. I like to see about getting my heart rate up with 15 or 20 heavy swings, 15 sec pause and then more swings with clean reps "can i get it up a few beats higher" mayn't be the smartest thing in the world, but it's brief and fun and well, it's again, something i'll be looking at over time - if there are changes in swing volume to achieve the same thing, measuring fatigue and so on.

Biofeedback again? Heart Rate Varability Fatigue and Recovery
There's some work that suggests monitoring those R-R distances can also be used for very specific training tuning. I'm looking forward to trying this in march - you need ten days of non-training to get a base line - time i don't have to take away from prep work right now. But from this, and some nifty math, one can get a simple number that if one is above it, don't train; below it, go ahead.

I'll come back to this after i've played with it for awhile, but if you go for it, let me know. Fatigue has been desperately challenging to get a handle on. Partially because we tend not to notice it's got us until it's too late - the dreaded overtraining problem.

i'm intrigued by the fact that a phyiscal device far less subtle than ourselves may actually be able to help us learn to re-listen to ourselves - to be able to correlate our own daily experience with what the device is saying is our state. For instance on a day this approach might say "don't do a heavy day" - do i notice that ya, i'm not feeling like i could take on the world? or is there something else at play, that i might begin to learn to be more aware of?

This kind of biofeedback is reminiscent to me of another way that folks like Mike T Nelson, Adam Glass and Frankie Fairies are looking at immediate ways to test readiness for a particular move in any workout.

This kind of training - of finding ways to see and listen to our bodies - learn what the data is giving us - who knows? may just help us to move better, stronger, easier for longer.

For me, this heart rate tracking is new, so i don't have enough data yet to draw conclusions, but so far it's opened up more possibilities to get more volume safely into my workouts, and that seems to be good so far.

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SolidMastery said...

Such a timely post for me.
I primarily use timed weight training for maximum reps. As such, I often break up my single-side exercises (e.g., dumbbell triceps extensions) into two 120s intervals. I have noticed that regardless of which arm (or side) I train first, I am always able to do more reps on the second side. Note: I do not warm-up prior to weight training.

I guess its time to return to my old routine of 10 mins on the rope.

mc said...

thanks for stopping by. really interesting.
will you come back and let me know how it goes if you see a dif when you rope up again?


SolidMastery said...

Just wanted to let you know that I will report back when I can make an informed assessment as to if "warming-up" helps in squeezing out more weighted reps in a 120s time frame.

Early results are promising.

I did a progressive stairmaster (6-11 rate, 2 min increments for 12 min) and then performed an alternate side standing leg curl. Interestingly enough, for my first time, I squeezed out more reps on the first leg than the second. However, the rep numbers were very close. This is stands in stark contrast to my performance of that same exercise without a "warm-up". In fact, the rep numbers were significantly different.

The same thing happened during weighted-rep torso rotary twists.

But get this: the biggest shocker came with my squats. I normally just perform weighted-rep timed squats without a warm-up. However, today I did a progressive stairmaster (6-8, 2min interval for 6 mins) and then performed squats, In one month I went from 29x95lbs to 40x95lbs.

In hindsight, I guess this is obvious stuff.

mc said...

SolidMastery - i don't think this is obvious stuff at all - way to go on your progress and thanks for coming back on this: it's inspiring.



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