Measuring Energy Expenditure on the Bike A friend of mine recently gave me a call, and asked how accurate the energy expenditure was in the treadmill at his gym. He told me how his girlfriend obsesses over the calorie count on the machines, so that she can be sure she burned off that extra latte she had the morning. The short answer to “How accurate are those calorie counts?” is… “not very” There are dozens of devices that claim to measure energy expenditure during exercise. Some of them are located directly in the exercise equipment, while others are devices the user straps to his body in some manner, and all of them make estimates of the energy expenditure by measuring different variables. The most accurate way to measure energy expenditure, would be to use a metabolic cart…the machine that measure VO2. As you exercise, you use Oxygen and create CO2, the amounts and ratios of O2 utilized and CO2 created can be used to calculate the energy expenditure. This works well in a lab, but it isn’t very practical for measuring energy expenditure in the real world. The devices that a users wear or strap on typically fall in to three categories: heart rate monitors and accelerometers, and GPS. Accelerometers such as the “body bug” or pedometers that measure your number of steps, basically measure how much the user moves and the use this information to guesstimate energy expenditure. As you can probably guess, there is lots of room for error in this method. A device that is going to be more familiar to athletes is the heart rate monitor. Heart rate monitors typically work by measuring the electrical current in the heart. The users wear a strap on his chest, and then the information is sent wirelessly to a watch or other device. These devices give accurate information regarding heart rate, but the energy expenditure is a calculation based on algorithms. The heart rate monitor also makes several assumptions about the individual’s level of fitness, cardiac output, and environmental factors. As you can probably guess, there is quite a bit of room for error here as well. My undergraduate exercise physiology students once did a project compared Polar heart rate monitor’s measurement of energy expenditure to energy expenditure as measured by a metabolic cart. The students discovered that the Polar heart rate monitors were frequently off by 30%! GPS units estimate energy expenditure in much the same way as the accelerometers and the heart rate monitors. They use algorithms based on the type of activity, distance traveled and elevation. Once again, there is plenty of room for error. The GPS doesn’t ”know” if the cyclist is drafting, if she is in an aero position, what type of wheels are being ridden, or other numerous factors. These devices all give all ballpark figure for the total energy expenditure, but do not have a high degree of accuracy, and can frequently be off by as much as 30%. next time..gym equipment and bicycle powermeters

I haven't been posting to this blog so much the last few weeks.  I have been busy opening up my new indoor cycling studio.     Wether you are a Spinning enthusiast, a cyclist, a triathlete, or just someone who likes a good workout.  We have  some classes that will be good for you!

I have a new track class at the velodrome starting Aug 5th.  Be sure to sign up online as class usually fills.  Register here:

http://www.cyclingscience.org/sdvelodrome.htm

The last blog post  discussed leg speed intervals and neurumuscular adaptations.  Now we move on  to how to do leg speed intervals:

The principle of training specificity says  that  training adaptations are specific  to your training.  It’s a simple principle, but one that  sometimes gives athletes  a hard time.  People will ask me things like “Do you think doing some trail running is good training for cycling?”  My answer is: You get better at riding the bike, by riding the bike.  Trail running is excellent off season cross training.  But the best way to get better on the bike is to ride the bike.  …same goes for  swimming, rowing, weight training, etc.

When  you do  leg speed drills,  you need to follow the principle of training specificity.    Think about when you need to use high leg speed in a race or group ride…. it  is when you are going hard.

So,  leg speed drills is that they have to be done at high power.  Power should be 80+ percent of your threshold power.  High RPM and high power.   If you don't use a power meter, than  think about doing them at or near race pace.   High RPM but low power will not help you become more efficient at high RPM pedaling.  The neuromuscular response required to pedal at 110 RPM  while cruising down PCH, is not the same  neuromuscular response  that is required to  pedal at 110 in a race.   I have even seen a coach have their riders do leg speed intervals with NO CHAIN.  Tiring yes, don’t expect it to make you a better pedaler when it counts. 

 

I also seen riders doing high RPM  workouts at leg speeds that are significantly above their ability level and they are practically popping out of the saddle with every pedal stroke.  Again…. these riders are probably not getting the desired training effect.  They are so incredibly  inefficient  at those RPMS that there is little or no training effect.

 

Another  workout that I see riders doing is riding fixed gear on the road.  You’ll see riders going 35 MPH down hill, riding in a very small gear, and pedaling at 200 RPM.  These riders aren’t developing their high power leg sped either.  The neuromuscular response required to keep your legs moving at 200 RPM, while they are being forced to spin that fast by gravity and a fixed gear, is not the same as the neuromuscular response required to pedal fast in a sprint.  This means little or no desired training adaptation. 

 

Leg speed drills need to be highly specific to produce the desired training effect.  They need to be both high RPM AND high power.   These drills should be done at threshold power or above, and should be done at an RPM that is just a little bit above the rider’s comfort zone.  Too high of an  RPM, or too low of a power output simply won’t provide the desired training effect! 

We'll finish up with a few workouts that I sometimes give my athletes:

Legspeed workout 1: Slowly spin-up to max rpm over 30 seconds. When you begin to bounce, back off and then hold it for several seconds.   Power be 90-120% of threshold power.

Use the cadence mode if you have it.   Do 5 X5 minutes of spinning on the high end of your comfortable range.  HR zone 3 or 70%-80% of yout threshold power on a flat to  gently rolling course. Note and record your average cadence for the ride when done.

I’ve been doing quite a bit of riding and coaching at the San Diego  Velodrome lately, and that’s got me thinking about something most  cyclists, but specifically track cyclists think about a lot… leg speed and; legs peed intervals.  Trackies think about  leg speed and  leg speed intervals is that track riders can’t change gears while they are riding.  Whatever gear you put on for a track race, you are stuck with it the whole race.  You have to pick a gear that will allow you to get the top speed required  for sprints, but a gear that won’t leave you in the dust when the group accelerates from 20 miles an hour.  Having good leg speed, or the ability to produce power at high leg speeds, is an important skill for a track rider, because a rider with exceptional leg speed can ride a smaller gear and therefore accelerate more quickly, while still achieving acceptable top end speeds.  Good leg speed is also a great tool in for road racers, as it always good to have one more tool in your tool belt, to be able to accelerate out of that corner, or up to that wheel on front of you without shifting gears. 

 

A biomechanically efficient pedaler, when compared to an inefficient one, uses less oxygen, and less energy, to do the same mount of work.  For most riders, their biomechanical efficiency goes down as leg speed gets near and above 100 RPM.  I’m not talking about pedaling circles here (pedaling circles is not desirable, but that is an entirely different topic).  I’m talking about pushing on the pedals at the right time, or not pushing on the pedal  when it is trying to come back up and around.  That is a waste of energy, and that’s when it looks like you are “pedaling squares.”  

 

Some riders are naturally more biomechanically efficient than others.  I know a former pro rider that pedals beautifully  at any RPM… he just looks smooth.  You may not be one of those naturally efficient pedalers, but  you can do drills to work on your biomechanical efficiency….leg speed drills.    People have lots of crazy ideas about leg speed drills, the problem is that the drills people do are frequently not specific enough to   create the neuromuscular response that will cause a training effect that will make them more biomechanically efficient at those high leg speeds. 

Next time:   How to do, and not do leg speed workouts

 

 2 of the riders who went down last week came to class last night  just to say hello, and let everyone know they are alright.   Both riders were in pretty good condition.  They drove themselves  to the track, and are already talking about getting back on their bikes.   Rob T has had some facial surgery, and actually looks pretty good.  He'll be as handsome as ever once the swelling goes down    Nick suffered some broken ribs, and still has a little pain when he  takes in a deep breath, but should be fully recovered fairly soon.  Derrek didn't make it out but he's doing fine.  He might need surgery on his shoulder, but  my experience is that with shoulder separations, most people choose to forgo the surgery.

That crash was pretty ugly, and going away in an ambulance is never good, but these guys are well on their way to recovery.  Iam actually really glad the guys came out, I think it  did a lot to allay the fears of some of the beginner riders that have never seen a crash like that before!

I got this from Rachelle B: 

"As of Friday, Alex said that Rob would be getting released shortly, so I assume by now he is out of the hospital.
Alex also told me that one of the 4 broken ribs that Nick had punctured one of his lungs, but I dont think it was too bad. They were thinking that it would heal itself, but also were gonna have to wait and see. I forget when or if Alex said he was going to get released."

If anyone is wondering, I just got this from Alex M:

"I've been checking up on Rob and Nick.  They're both still at Scripps Mercy in Hillcrest.  Rob broke his jaw in two places and fractured his cheekbone. He had surgery this afternoon to put six plates in his jaw and cheek.  It seems to have gone pretty well, and he didn't need to have his mouth wired shut.  Nick broke four of his ribs and one of them punctured his lung.  Right now he's on oxygen and doing breathing exercises to see if it heals but they might need to put a tube in his chest.  They'll both probably be in icu until they improve a little, but that could be as soon as friday."

 I've been riding bikes for over 15 years now, and racing them since 1997.  In  that amount of time, you see your share of crashes.  Crashing is just  part of bike riding, and even more a part of racing.    Even with the most experienced riders...crashes still happen.  You accept that fact, but those crashes still suck...especially when riders have to go away in an ambulance.   We had a pretty ugly crash during the  adult track  class last night... and three riders got an " unplanned chauffer" to the hospital.      It looks like we have several riders that are going to  be in pain for a while, but everyone is going to be OK.  I'll be posting updates here a I recieve them.

What I have so far:

Big Rob T  has broken   multiple bones in his face, is wearing a neck brace  and is scheduled  to have surgery today.   Full recovery expected.  I believe he is at Mercy Hospital at the moment, but me be moved to a Kasier hospital for the surgery.   ( information directly from his mother)

Derek  had a separated shoulder and was released from the hospital last night. ( information secondhand)

Nick apparently broke some ribs, has some back pain, and was reportedly in the ICU as of thursday morning ( information seconhand)

I'll be posting any future information here.  Feel free to email me if you have any insight.   email me at: myfirstname@cyclingscience.org

Sean

PS

Just got this from Rachelle B:

 "Derek will be going to an orthopedic to determine whether he will need surgery or not on his shoulder....  Rob seemed a lot better in the hospital last night when we saw him up in ICU.  He was even cracking jokes which we were really glad to see, considering how bad off he was at the crash.  Nick seemed ok last night...maybe the worst off out of the 3.  We talked to him also, but he seemed like he couldnt really move at all and was in a lot of pain"

 

Since I  Rachelle saw  all of them last night, I assume they are all at Mercy. I am not posting last names here, but if you are in my track class and want  someone's last name so that you can call or pay a visit, feel free to email me.

So.... I teach the adult developmental classes at the San Diego Velodrome.  The classes are 6 weeks long.  I love coaching these track classes, the  riders learn how to ride and race track bikes and everyone has a great time.  The classes are tons of fun, but my favorite night is the last night of each session.  I always tell the students " We go to Lefty's Pizza the last night of class.  If you had fun, you buy one of the coaches a slice of pizza or a beer.  If you didn't have fun....we get to buy our own dinner" 

 They say a picture is worth a thousand words.....take a look a this photo of my assistant coach Jesse, and  the 5 beers in front of him will tell you  that lots of people had fun:

If you want to take track class, the next one starts June 17th.  You can find more information here:
http://cyclingscience.org/sdvelodrome.htm

I recently wrote about  coached rider Tammy Wildgoose from UC San Diego being chosen as part of an all star collegiate women's cycling team racing at the Nature Valley Grand Prix.  Velonews.com recently posted a short article about the team:

Collegiate All-Star women chosen

I friend of mine sent me this photo the other day.... this looks like a fun bike to ride...

I've been coaching Tammy W since the end of last summer. Tammy is a student at UC San Diego and she has been concentrating on collegiate cycling, with a goal of peaking at the Collegiate National Championships. Tammy has had a few good results along the way, but her best result of the year was by far her 3rd place Collegiate National Championship Criterium. As a result of her results that weekend, Tammy has been invited to race on a composite womens team at the Nature Valley Grand Prix Pro Stage race!

This is the new spot for this blog... there are a few years worth of old posts here: http://cyclingscience.blogspot.com/

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