Power vs heart rate

Does heart-rate training still have a place or are power meters now essential to success?

Power meters are ubiquitous now at the pro level. By measuring wattage, riders and coaches can quantify not only their real-time output, but the training load for every interval, race, training week and more. Does this mean that training with a heart-rate monitor is outdated and less accurate? Well, that depends who you ask. We talked to several experts, from physiologists to to WorldTour team managers to elite coaches.

Q: Will a power meter improve my riding?

A: Used correctly, in most cases, the answer is yes. They can eliminate guesswork in your training, help you train more specifically and help track your performance over time. But a power meter is a tool, not a magic bullet.

In a perfect world, an investment in a nice power meter would make you go faster instantly. But unlike the latest state-of-the-art aero bike or lightweight carbon hoops, a power meter only offers only the potential for speed. 

“It’s easy to expect too much and it’s something we see relatively often,” says Elliot Lipski, physiologist and cycling coach at trainSharp. “At the end of the day, the only way to get better is to put in hard work. It’s up to the rider to produce the power themselves – unless, of course, you have a motor in the bike!”

Q: Are power meters essential to success in cycling in 2015?

A: It depends on who you ask. Among elite cyclists, those not using power meters are few and far between. However, they have both the access to the expensive devices through teams or sponsorships and, crucially, the coaching expertise necessary to analyse the data.

But as an aspirational amateur, do you need one? If you’re a racing cyclist, the answer is yes, according to Lipski. In training they can benefit everyone, he says, while in racing it’s more discipline-specific: vital in time trials, where success and failure depends on following pacing strategies; less so in a road race, where going with attacks might be necessary regardless of whether ‘computer says no’.

For coach Ben Wilson of Personal Best Cycling Services, power meters are a “valuable addition to an amateur cyclists’ toolkit”, but are by no means essential. “It’s easy to get caught up in technology but for most of my clients cycling is a hobby and, as such, should be fun,” he says. “There is no substitute for getting out on the road and riding a bike.”

Q: I have a heart rate monitor. Will that still help me?

A: There’s a popular belief that heart rate training is ‘old school’ and power training is ‘new school’. Lipski, for example, says that those using heart rate as opposed to power – assuming it’s not a financial decision – are likely to have an “old school mentality”, while coach Nick Thomas refers to heart rate as “dated training.”

In Hunter Allen and Andrew Coggan’s book 'Training and Racing with a Power Meter', they go as far to say that going off heart rate alone could easily “mislead you about your performance or even undermine your confidence”.

Since heart rate is influenced by so many other factors, such as hydration, stress and lack of sleep, they argue that sometimes you’re better off simply using perceived exertion, or “feel”.

But that old school tag is unfair, according to Dr Iñigo San Millán, an exercise physiology professor at the University of Colorado School of Medicine, who has tested riders on the Cannondale-Garmin pro team for the past six years. While an advocate of power meters, he says that without heart rate data to complement power data you’re not getting a true picture of the physiological cost of your training: “[A power meter] is a great tool, but I think people are going to the extreme by saying heart rate is old school. It’s not at all. You still see in sports like track and field, running and rowing athletes still training with heart rate in a very scientific manner. With heart rate you’re actually using a physiological parameter. Watts are the end product of the physiological and metabolic events [in the body].”

While there is a bit of a lag in heart rate (red line) versus power (dark purple, second line), both are helpful training data. power shows the work you're doing; heart rate shows how you're handling the work:
While there is a bit of a lag in heart rate (red line) versus power (dark purple, second line), both are helpful training data. power shows the work you're doing; heart rate shows how you're handling the work:

While there is a bit of a lag in heart rate (red line) versus power (dark purple, second line), both are helpful training data. Power shows the work you're doing; heart rate shows how you're handling the work

Q: Can a heart rate strap be as valuable a tool as a power meter?

A: When asked to choose either a power meter or heart rate monitor to coach their clients, both Lipski and Wilson opted for a power meter – Lipski for its ability to target training exactly to the relevant zone and energy system, Wilson because training can be quantitatively tracked through software like TrainingPeaks, and because heart rate data can be, as per Allen and Coggan, unreliable.

While all are in agreement that the perfect world option is to train with power and heart rate, San Millán says he’d choose heart rate training over power. Perhaps he is coming at it more from an athlete wellness rather than performance perspective, but his view goes back to a trend he’s noticed when it comes to cyclists and power meters: overtraining syndrome.

“Watts are not watts” is a phrase he repeats a lot. By this he means the watts figure, as measured by a power meter, is the end product and doesn’t take into account the metabolic responses in the body. Power training plans, he adds, often assume that the same wattage over time presents a constant metabolic response, which, according to his own research, isn’t the case.

“Let’s say your coach tells you to train at 250W in zone two for four hours. They’re assuming your metabolic response is going to be the same throughout that four-hour period, but that’s not true in many cases.”

He cites his own study from the University of Zaragoza (San Millán, Gonzalez Haro, Irazusta and Gil), which put two groups of cyclists, elite and recreational, through a 15-minute ergo test at fixed power outputs of 80 percent and75 percent peak power, respectively. They found that, even though power output was kept steady, physiological parameters (HR, lactate and VO2 max) changed over time.

Physiological stress increased as the test went on and, they concluded, should be taken into account when drawing up power-based training plans. Training to inaccurate zones, over a prolonged period of time without appropriate rest, can lead to a plateauing or drop in performance and motivation.

Q: Is overtraining still possible when using heart rate and power together?

A: Not if you’re working as part of an effective coaching unit, according to San Millán. Power data is a complex equation, even more so when paired with heart rate, so having an expert evaluate the data is vital. Both he and Lipski agree that it’s important not just to have a coach, but that your relationship is closer than just firing over the occasional email.

With heart rate data, says Lipski, “you can spot early onset signs of illness and fatigue through combining the data [with a power meter]. This, along with subjective measures and a good rider-coach relationship, means that we can monitor performance and fatigue effectively.”

A Spaniard teaching in the US, San Millan’s experience of seeing burnt-out cyclists has come mainly in his adopted country. “In Europe we have more of a tradition of physiology and a scientific approach to cycling. In the US there isn’t that sophistication. A lot of cyclists buried their heart rate monitor a decade ago.”

That, as he’s already made clear, is a recipe for disaster. “[With a HRM] you might know you go up a climb [at a certain power] at 175bpm, but that on a given session you can’t get it over 155. That’s a typical sign of overtraining. If you bury heart rate, you will never see that.”

Ultimately, believes Lipski, the key to avoiding overtraining is a strong relationship between rider and coach, where both learn to understand how the cyclist reacts to exercise and are able to quickly adapt training to suit their needs.

Q: Is there any other tool in development that might soon make power meters seem ‘old school’?

A: The ultimate goal, says San Millán, would be to train with a lactate meter. Lactate is a byproduct of glucose utilisation in muscle cells during exercise and its accumulation in blood increases with exercise intensity. Hydrogen ions, which build up along with lactate, may interfere with muscle contraction and inhibit performance. Lactate threshold describes the point at which lactate production exceeds the body’s capacity to clear it, leading to a drop in performance.

In San Millán’s study, lactate levels were found to increase directly with heart rate, so being able to measure lactate gives a clear picture of the body at the metabolic level.

Don’t expect to see lactate meters in everyday use anytime soon, however, as testing is only possible in the lab for now. “We’re working on some possibilities,” says San Millán. “Maybe in a decade [we’ll see something]. I’ve been talking to biosensor companies, but we’re not there yet.”

Today, the standard lab measurement of blood lactate is done with pinpricks to a finger while steadily ramping up power while riding a trainer. Future technology, such as biosensors, will be faster, more sophisticated, and less painful. The first human tests were reported in the journal Analytical Chemistry in 2013 and were applied to the skin like a temporary tattoo.

Q: If I do buy a power meter, then what?

A: Getting tested will give you the training zones that you should be working to. This is best done in the lab, says San Millán. “Problems such as overtraining occur when you don’t dial [Zones] in very well. You might end up thinking you’re training in Zone 2 when in fact you’re in 3,” he says.

As already mentioned, it’s best not to go it alone. James Llewellyn, a 24-year-old cat 3 racer and recent power meter convert, “played about” for months before getting in touch with Rowe & King, the coaching company set up by pro cyclists Luke Rowe and Dani King.

“If you don’t understand the figures, a power meter is pointless,” Llewellyn says. In five months working with them he’s raised his Functional Threshold Power (FTP), or hour power, from 245W (2.88W/kg) to 320W (4.1W/kg) and says hitting the prescribed numbers and sending it to his coach is a huge motivation. “It’s nice to have an experienced coach,” he adds, “but I like having an understanding of what the data means myself. It helps when discussing future [training] sessions.”

Q: But if I choose to train with a heart rate monitor, I’m not going to get left behind?

A: Heart rate training on its own still has a place. Even at WorldTour level, Cannondale-Garmin boss Jonathan Vaughters supports riders who choose not to use power as part of their training. “[Power] is a great tool, if used correctly," he says. “But if over-used and over-simplified, power measurement probably hurts training.”

There’s no denying that a power meter, used alongside heart rate, is the best way to train for the majority of cyclists, allowing you to create a training diary, track improvements and spot fatigue. But this information is only useful in the right hands. If you don’t have the expertise or motivation to really tap into the device, power meters are at best an expensive curiosity, at worst a shortcut to burnout.

If power training isn’t for you, however, fear not. As with Rowe & King, Thomas has seen his clients “massively improve” their power (by around 50W over 16-20 weeks) using only heart rate training, with power feedback only coming during subsequent tests.

“If you’re training to just heart rate,” adds Lipski, “you should still make significant improvements. It’s dependent on the sessions you complete and the rider-coach relationship to ensure that the training is progressing in the right direction with the correct management of fatigue.”

 POWER

  

 HEART

 

 Training Detail

 Coaches Notes

 

Training Detail

Coaches Notes

Progressive warm-up, working through your Zones. Ride for 10 minutes with your power in the following Zones;

2 minutes Zone 1,

3 minutes Zone 2; and

5 minutes Zone 3.

Then reduce your power, riding steadily for 3 minutes in Zone 2 with 1 x 6-second max sprints during each minute.

2 minutes in Zone 2.

Make a note of the max wattage for each of the sprint efforts.

1. Warm up should be progressive

2. Gently work your way from Zone to Zone (working from the lower to the top of each Zone).

3. The max sprint efforts are both part of the warm up, and a training discipline in themselves – so commit fully to them.

Warm Up

Progressive warm up, working through your heart rate Zones. Ride for 10 minutes with your HR in the following Zones;

2 minutes in Zone 1;

4 minutes in Zone 2; and

4 minutes in Zone 3 (through each Zone, try to progress steadily from the lower to the top end of the Zone, creating a constant increase in effort).

2 minutes easy in a light gear (HR is not important).

3 minutes at Zone 2 with 1 x 6 second max sprint during each minute.

2 minutes in Zone 2.

1. Warm up should be progressive

2. Gently work your way from Zone to Zone (working from the lower to the top of each Zone).

3. The max sprint efforts are both part of the warm up, and a training discipline in themselves – so commit fully to them.

 Ride for 5 minutes at your threshold wattage. For the last 15 seconds of each minute ride as hard as you can – this is a max effort sprint each minute. Do not rest after each 15-second max effort – maintain your threshold wattage.

Make an note of your average wattage for your 5-minute block. You can look at your first effort as a PB. From then on it is for you to challenge yourself and set new PBs which will show improvement.

 Set 1

Ride hard for 45 seconds with the aim of hitting your threshold heart rate towards the end of the 45 seconds. Then sprint as hard as you can for 15 seconds. Drop back into the pre-15 second sprint intensity. Allow your HR to drop back to threshold over the next 45 seconds then repeat the max effort. Continue this 45/15-second effort for a total of 5 minutes.

 

Due to the lag between effort and HR update there will have to be an element of feel with this session. The HR monitor is a guide only. An excellent indicator of fitness is how quickly your HR drops. Make a note of the drop during the first 1 minute between sets. Calculate this as a percentage of the HR at the end of the set.

 

 4 minutes very easy (Zone 1).

 

 Recovery

 4 minutes very easy (HR in not important).

 

Ride for 5 minutes at your threshold wattage. For the last 15 seconds of each minute ride as hard as you can - this is a max effort sprint each minute. Do not rest after each 15 second max effort - maintain your threshold wattage.

 

Set 2

Ride hard for 45 seconds with the aim of hitting your threshold heart rate towards the end of the 45 seconds. Then sprint as hard as you can for 15 seconds. Drop back into the pre-15-second sprint intensity. Allow your HR to drop back to threshold over the next 45 seconds then repeat the max effort. Continue this 45/15-second effort for a total of 5 minutes.

 

5-10 minutes easy spinning. Use a light gear and spin the legs. This will help flush out the lactic acid from your muscles and start the recovery process.

 

 Warm Down

5-10 minutes easy spinning. Use a light gear and spin the legs. This will help flush out the lactic acid from your muscles and start the recovery process.

 

This article was originally published in Cycling Plus magazine, available on Apple Newsstand and Zinio.

After early cycling flirtations with the Tour de France on childhood holidays, John Whitney fell for it hook, line and sinker in his mid-20s as an escape from the more sedate sports of his youth. As a classically trained news reporter, he snagged his dream job as a cycling writer straight out of college and is now fully immersed in the industry and wouldn't have it any other way.
  • Discipline: Road

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