Tag Archives: bike fit

Road vs. Cyclocross Bike Fit: what’s the difference?

A lot of hype concerning the difference between fitting a road bike and a cyclocross bike could be cleared up if we all agree on two simple things: put the engine in the right place, and then adjust for handling and comfort. Let’s break this down.

Saddle position

Your pedals are driven by large muscles surrounding the trunk, hips and knees. In fact, about 98.8% of the force you deliver to the pedals comes from your hips and knees. That’s right, the ankle only produces a very small percentage of your total power. So it makes sense to have the saddle height and setback (also called for-aft position) the same between your road and cross bikes to maximize power production. Why would you select a saddle position that compromises power output? Keep it simple. If you like your current saddle placement on your road bike, there is zero reason to change it on your ‘cross bike.

Handling and comfort

Good bar position allows you to move around while properly weighting the front end for corners and technical terrain | Photo © Jill Rosell Photography

Good bar position allows you to move around while properly weighting the front end for corners and technical terrain | Photo © Jill Rosell Photography

Okay, now here’s where things are a bit different. Instead of rolling your slick tire down fresh asphalt, you’ve got to contend with dusty pumice, wet grass, rocks, roots, and the nutrient ‘crossers crave: mud! In short, it’s critical to have a good handling front end. This means that you want to have a little less weight on the front so that you can lift your front end over obstacles easier. Careful though, too little weight on the front end will bring your torso too upright make it hard for your front tire to bite and send you skittering wide towards the outside of the turn. Let’s see how this all plays out in fit.

  • ‘Cross bikes typically have a higher bottom bracket. If you were smart, you’d kept your saddle in the same place as your (properly fitted) road bike.  This means that your saddle is higher in the air than your road bike. Since your saddle is higher, your handlebars also need to be higher.
  • Hand-grip placement for optimal handling: A lot of people rarely use their drops on their road bike. Then when on the ‘cross course, they find that they are forced into the drops on steep downhills to brake and get a better grip on the front end. Most riders find the bike is much more stable when conditions get squirrely if they use the drops. So if you are going to be in the drops, make sure you are comfortable.

So what’s the secret recipe to make sense of it all?

It’s simple really; the goal is to get the bars a bit “closer” to you. And you can do this in three different ways. You can run a shorter stem to move the bars closer, you can run your bars higher (by putting a few spacers under the stem or by using a stem with more rise), or a combination of both. I typically recommend that riders start by raising their bars first (because this usually only means moving spacers or flipping a stem). Setting up the bars with some combination of “up and back” will allow you comfortable access to the drops for good grip and handling, and while still allowing you to have optimal engine placement so you don’t lose any precious watts.

Powerful, sketchy, and somewhat comfortable. Yeap; sounds just like ‘cross racing!

Linsey Corbin’s Lucky 13: kudos from the field

I work with many athletes – and to be honest, I get just as much personal satisfaction seeing a person complete their first 10K as I do helping an elite earn a spot on the podium.  I’m always humbled and honored when athletes seek out my help, and even more humbled when they put out some nice footage such like this as a way of saying thanks.  I’m really just trying to do my job!

Well, professional triathlete Linsey Corbin is also trying to do her job with a stellar performance in Kona 2 weeks from today. Check out Day 2 on linseylucky13.com to learn what Linsey and I have been working on together.

Circles vs. Squares: What’s the best shape for a powerful cyclist?

If there was ever a good topic for an episode of Mythbusters, it would be this: should you pedal circles or pedal squares? We’ve been told that “pedaling circles” is important so that we can apply a smooth even pedal stroke. And word on the street is that this uniform application of power around the cranks is more efficient and makes a better rider.

We’ll lets mock up our own episode of Mythbusters. Let’s pretend that you are doing your thesis on power production in cycling (I did). And let’s also pretend that you are trying to get good data on good cyclists (this was my goal). In my research, I tapped into the best client database I could think of (the US Olympic Training Center). And lastly, let’s pretend that you could examine the pedal cycle of the entire national team, and developmental athletes (I could).  What would you find?

We’ll, this episode of Mythbusters would be pretty clear. World championship and Olympic medals have been won by riders who feature a smooth pedal cycle (circles) as well as cyclists who are mashers (squares). Uh oh. Don’t’ you hate it when real world data flies in the face of what you’ve been told. So where does this leave you?

Spin Scan Pedal Profile: Looking different doesn't mean one is better

Spin Scan Pedal Profile: Looking different doesn’t mean one is better

Its not to say that pedaling style is not important, because it is. In fact, research shows that elite cyclists have better pedaling mechanics than both recreationally competitive cyclists, and even elite triathletes. So if its not the “shape” of the application of power, what does better pedaling mean? Better cyclists have lots and lots of practice turning the pedals over. All this “practice” helps them produce the right amount of force from each muscle, without fighting, or co-contracting muscles during the pedaling cycle. They ride smoother and don’t fight their own pedal stroke. They also can change their pedaling cycle easily when they fatigue, in breaks, or up climbs. Having lots of “strategies” to tap into help as them adapt to the race conditions and terrain they are facing.

The take home:

▪   If you are a rider that has had success mashing your way along at 75 rpm, it doesn’t mean that you must learn to spin at 110 rpm just because someone else does.

▪   Pedaling technique is a variable that better cyclists adjust based on terrain, fatigue, and surface. It is still worthwhile to learn proper pedaling strategies. If you do want to improve your spin, the most beneficial cues are to “scrape mud” off the bottom of your shoe at the bottom of the stroke, and to “kick a ball” at the top of the pedal stroke.

▪   Traction matters. In general mountain bikers have a smoother pedal stroke to maintain traction. If they put all their power around a small part of the pedal cycle their tires spin out.  If you spend time on dirt, emphasize smooth power to keep your tires hooking up  – especially on the climbs.

▪   Better cyclists don’t necessarily pedal circles or squares. They just pedal better circles and better squares – stop reading and go for a ride!

 

 

Spin Scan Pedal Profile: Looking different doesn't mean one is better

Spin Scan Pedal Profile: Looking different doesn’t mean one is better

The Tipping Point: how does aerodynamics impact cycling?

Cycling is a balance act – you want to produce as much power as possible to make your bike move forward, while maintaining comfort, aerodynamics, handling, and safety. But quite often, we loose sight of the big picture in search of the “fastest looking position.” The most common question I get from time trialists and triathletes is, “Can you make me more aero?” Let’s tackle this issue head on using an example, and some science.

TippingPointPicSeveral years ago, I did a fit on a medical resident; we’ll call him Bill. He was three years into his cycling career and was doing quite well at the district and state level. He came and saw me for a bike fit on his time trial bike. His goals were to podium at state and place top 10 at nationals, and also to eliminate his low back pain on the bike. I’ll spare you the details, but after his fitting, his back pain was 100% gone, he won state, and placed 4th at nationals in the 40K time trial. The next year, he stood on the podium at nationals. Bill was very happy.

Right after nationals, Bill graduated and began making more income and sought out the advice of a wind tunnel to squeak out a performance advantage. The folks in the wind tunnel were able to produce a 28% improvement in his drag coefficiency. This is a very, very large improvement in aerodynamics! Bill left and was excited to see how this new position would play out over the season.

Well, things didn’t play out so well. Bill called after several months of riding in his new position. His back pain returned. He hadn’t made the podium in a single time trial all season. And he wasn’t able to hit the same power output on his new time trial position that he could easily hit on his road bike. Guess what we did? We adjusted his fit exactly back to where it was when we last worked together. Bill made the podium in his next race, and the next, and the next, and won nationals. Bill was happy again.

What happened? Bill hit the tipping point. Sure, he was more aerodynamic, but aerodynamics don’t make you ride fast; producing power does. Let’s back this up with some data:

  • The chief obstacle you have below 11 mph is the rolling resistance of your tires. At slow speeds, nothing matters more than tires and pressure.
  • When your average speed is above 25 mph we should begin to have talks on aerodynamics, and when your average speed is above 27 mph we really need to address aerodynamics. But for most riders, you’ll gain more speed by producing more power over your entire race distance rather than aiming to adopt a sleek, aerodynamic position.
  • Comfort matters. For most competitive cyclists, it’s likely you’re signing up events that 40K or longer. Those of you doing Ironman distance events are spending 5+ hours on the bike. Don’t try to replicate the overly aggressive position of a Tour de France time trailer (whose TT is quite short) just because you think it looks cool. You’ll end up so uncomfortable in your aerobars that you won’t be able to stay in them for long.
  • Power comes from your hips, not your knees. If I told you that you had a muscle in your body that had the best leverage of any other muscle, and was more resistant to fatigue, wouldn’t you want to tap into that muscle? You do have that muscle; it’s called your gluteus maximus. Strong quads are nice, but a proper position on the bike optimizes your glut to drive the pedals.

To get aerodynamic, most riders opt for a low, forward position to get their trunk down and out of the wind. This creates two issues. First, it compromises power by shifting emphasis from muscles in your hips (very fatigue resistant) to your knees (fatigue quicker). Poor compromise. Second, I’ve personally been in the wind tunnel with athletes and it is possible to get excellent drag numbers while maintaining a very powerful pedal stroke. This gets complex and very individualized, but good bike fitters can not only help you look better to the wind, but look better to the clock

 

 

Can I buy Speed?

Adam Craig gets his position optimized at the REP Lab prior to the season

Adam Craig gets his position optimized at the REP Lab prior to the season

Cyclists want two very simple things. They want to be comfortable on their bike, and they want to be fast. And anytime we “want” something, we must ask the question – how hard must I work to achieve it? Or in this golden age of cycling, a lot of cyclists ask a different question – can I buy more speed? Well, let’s stop asking questions, and start producing some answers.

As a physical therapist, I can tell you that cycling takes its toll on the body. You do a fairly limited range of motion over and over and over again for thousands of miles a year. If things are lined up properly on the bike, and you are careful and follow a smart training program, you’ll maximize efficiency and prevent injury. When things are “off”, we wind up with imbalances that manifest themselves as injury. Injury is a whole other topic for a latter time. The other problem we wind up with is poor efficiency. Proper knowledge and equipment go a long way towards accomplishing a goal of optimal fit.

I’d like to summarize a paper that was published in a peer-reviewed, independent journal. Asker Jeukendrup and James Martin wrote “Improving Cycling Performance: How Should We Spend Our Time and Money”. The authors wanted to quantify the effects of various cycling factors to see which was most beneficial from both a time and cost standpoint. In this study they use simulated “models” to arrive at their predictions. Since they aren’t comparing apples to apples and oranges to oranges, the mathematical models allow them to base time gains on previously established research findings (from independent, peer-reviewed journals). Instead of just saying, “bike fit helps”, the authors sought to quantify exactly how much help a cyclist gets with a given alteration in their program. If you ride for Team Sky, you can skip the rest of this, as your cycling resources are unlimited. However, if you are a cyclist balancing riding, school, wife, kids, girlfriend, busted radiator, food, and time at the dog park – read along. They examined both Internal and External Factors as shown below:

Factors Changed Time Savings Observed in 40K TT
Internal Factors
Training 1-7 minutes
Caffeine 55-84 seconds
Carbohydrate 32-42 seconds
Altitude Training 23-34 seconds
External Factors
Body Position 2-2.5 minutes
Aerodynamic Wheels 60-82 seconds
Wheel Weight 10-72 seconds (grade dependent)
Body Mass 19-25 seconds (rolling TT course)
Bicycle Mass 5-13 seconds (rolling TT course)

You can see that the old adage holds true – there is no substitute for training. Period. Got it? Yes – you have to ride you bike. And you have to ride smart. Lots of base, properly periodized training plan, intervals, and a good taper all add up to good performance on race day. Aside from training, this article offers some interesting findings on where we should concentrate our efforts. Bike fit is key. It’s free speed. Faster with less effort and more biomechanically sound. It’s a win-win all around for the time and money you’ll invest and performance gained. Also – it’s a benefit that is there every time you get on your bike. You are always reaping the benefits of training in the most optimum position. It is very different then spending 1200 dollars on a pair of wheels you only get the benefit from 5 or 6 days a year.

At the REP Lab, we use a whole lot of technology, knowledge, first hand trial and error, experience, and common sense to achieve the most optimum fit for you – not a formula out of a book. A solid bike fit gets you a whole lot closer to achieving your optimum performance now.

I encourage you to check out the full article if you want more information:

Jeukendrup, A.E., and Martin, J. Improving Cycling Performance, How Should We Spend Our Time and Money? Sports Med; 31(7):559-569

Brain Power: Athletes, Coaches, and Clinicians – Join us for a great event in Bend, or beyond

Today, we’ve got a smattering of amazing educational opportunities to announce:

This Thursday in Bend, OR @ 7:30 at the Westside Clinic: Athletes – Please join Jay Dicharry PT (REP Biomechanics Lab Director) Matt Lieto (Pro Triathlete) and Keats McDougal (Ironman Canada & Tahoe Director) for a night of Mobility and Multi-sport discussion. Jay will provide the latest research on mobility and best practices for multisport athletes. We’ll answer the most common questions: What does stretching do for the body? When should you stretch? How long? What’s the difference between dynamic warm-up and stretching? And how does soft tissue work play into this whole discussion? Next,  Matt will discuss his training plans and and upcoming race prep considerations. Matt will show you how the lessons he’s learned along the way can help you prepare better for your next event. Finally, Matt will lead a Q and A with Keats. They’ll provide an overview and considerations of these two challenging courses. It will help you prep for this year’s race, or feed your stoke for next year!  Stick around after for a question and answer session with our panel. And yes, we’ll have beer. Cost: free. No brainer!

This weekend in Boulder Colorado (7/13-7/14): Calling all healthcare professionals – are you tired of getting your information on running mechanics from the mainstream media? Would you be interested in a immersive weekend of education that is based around hundreds of peer-reviewed articles, hands on clinical assessment, and gait cues? We’ll construct a framework of what we know about running mechanics and their effect on performance and economy. And more importantly, we’ll show you how this information applies not just to the masses, but to your individual patients. In short, this is all the stuff you wish they had told you in Med school, PT program, or ATC curriculum. There are still a few spots left. See here for details.

August 23-24th in San Jose: Tri-athletes and would-be coaches- are you looking to get your Level 1 certification? Then join us for the USA Triathlon coaching clinic. Two days packed full of essential knowledge to help you and your athletes succeed.

Sept 21st and 22nd in Bay Area: Running Coaches – this one is all for you. We are going to delve into the truth behind running mechanics, screening strategies for your team, the impact of strength training to improve performance,  discuss the role of footwear, and more. Andrew Allden chairs this event – he’s brought in a knock out panel each and every time –  Learn to think outside the box to take your team to the next level @ this USATF Level 3 Coaching Seminar. More info here

Yea, I know – blogging and tweeting is supposed to make us all smarter. But you know what really makes us smarter? talking face to face. See you soon!