Aerobars Can Maximize Cycling Performance

Authored by Brady Holmer • 
January 31, 2019
cyclingtraining

1989 might be the year cycling speed got hacked, when United States cycling star Greg Lemond revolutionized the Tour de France forever. Trailing the leader by 50 seconds and headed into the final time trial, Lemond unveiled a secret weapon.

Using radical new bike handlebars called “aerobars” (designed by a former US national ski team coach), Lemond made up his deficit and then some, flying through the time trial and winning by an eight second margin. In a style no doubt inspired by the product’s designer, Lemond’s position resembled that of a downhill skier. Fluid, aerodynamic, and most importantly–fast.

Ever since Lemond ushered cycling’s “aero revolution,” the understanding and importance of cycling aerodynamics has exploded. Now, all cyclists have access to techniques that can improve performance by one simple addition. If you’re a cyclist or triathlete looking to take speed to the next level, adding aero handlebars to your bike wish list might be a good idea.

Not Your Ordinary Handlebars

Most road bikes run with drop bars. The downward curving grips seen on most standard road bikes are easily recognized and provide decent comfort while in the saddle, but require a more upright riding position.

Aerobars, also called tri-bars, aerodynamic bars, aero bar extensions, or clip-on aerobars, are usually handlebar extensions to your two-wheeler. Aerobars look like a horizontal fork (with an s-bend curving up or j-bend curving down) mounted on top of traditional drop bars, extending off the front of the bike. The two horizontal “skis” have grips at the ends to allow for steering, and two padded cups let cyclists rest their forearms comfortably while riding aero. There are many different types made from many materials: aluminum aerobars or carbon aerobars are popular options. An aerobar set is usually purchased and then attached to a TT bike or triathlon bike (less frequently are they attached to mountain bikes). They can usually be attached easily with a common multi-tool set.

Other than looks, the main difference between drop and aerobars is riding aerodynamic position.

When riding in aero, your torso is stretched out along the bike in an exaggerated forward lean, arms tucked in, and head down. While awkward, aero does what it is designed to do: reduce aerodynamic drag and improve cycling speed and performance.

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Fight the Resistance

Cycling aerodynamics are as fundamental to success as power production, especially at the elite level and at higher speeds. Most of the power cyclists generate doesn’t go to turning those gears, it’s needed to simply overcome drag force.

What is drag force? Without a trip back to high school physics, drag can be mathematically described as the sum of the aerodynamic drag coefficient, the surface area of the cyclist, and the velocity of the rider relative to the air.

Fd = Cd x A x V2

Where:

Fd = the drag force (this is the part we want reduced)

Cd = the coefficient of aerodynamic drag

A = the area facing the airflow (you)

V = the velocity of our rider relative to the air around the cyclist

A larger surface area and a faster speed require a greater drag force to overcome.

Aerodynamic drag accounts for 90% of the total resistance cyclists experience out on the road.

Cyclists have two options to cut down on the drag: reduce speed (not ideal for anyone) or reduce surface area.

Aerobars solve the drag problem by influencing area. Aero position reduces the amount of “you” that is exposed to the oncoming airstream, lowering aerodynamic drag. Our bodies are poorly designed, aerodynamically speaking. Adopting a streamlined aero position makes us more slippery as we ride through the air.

Studies show aero position dramatically reduces aerodynamic drag compared to standard “upright” and “drop” positions. Cyclists who adopted “time trial” (i.e. “aero”) position reduced frontal surface area by 13% and lowered aerodynamic drag by 7%, leading to a combined 19% reduction in total drag during a wind tunnel ride.1 A further modification of aero, known as “Obree’s position,” has been shown to reduce wind resistance by 27.8% compared to standard upright cycling.2

Anatomy of Aerobars

Riding aero requires cyclists to dramatically alter riding position. Many athletes find this position uncomfortable. Reaching across the bike to get that low back angle puts stress on your shoulders, overextends the torso, and puts pressure on the lungs and stomach. Spending time in this position takes some getting used to, and might be worth it in the long run. As Vittoria Bussi, HVMN athlete and women’s World Record holder in “the Hour” knows, sometimes, to achieve your personal best, you have to learn to “stay in an uncomfortable zone as much as you can.”

New positions mean new muscle activation patterns and potential performance impact. Trunk orientation may actually change how muscles in the hips and legs activate. Triathletes cycling in aero position had a significantly increase electrical activity (determined by EMG) in their gluteus maximus and vastus lateralis muscles.3 A slight increase in muscle activation at the same workload might mean more neuromuscular fatigue, and a drop in performance because of it. Training more in aero could improve these patterns.

Pain in the Neck

Even when saddle height and bike fit are optimal, the different seat, knee, hip, and back angles adopted in aero position put extra strain on muscles. Two of the most common injuries related to aero position in cyclists are to the hamstring and the erector spinae–muscles that straighten and rotate the back. Injuries occur because riding aero puts these muscles in a position that stretches them beyond their capabilities for extended periods of time. Lower back pain is a common symptom of adjusting to riding in aero.

Do a deep toe touch. Now hold it...and continue holding this position for two hours. This is what riding aero feels like: a prolonged deep stretch of the lower back and hamstrings. The lower and longer you go, the more stretch and microtrauma may occur deep inside the muscle fibers. Stretch too far, and you’ll pull a hammy.

Prolonged flexing of the upper body significantly curves the spine, known as “kyphosis.” It also hyperextends the neck, and packs the knees and hips close together, reducing their angles. Saddle height is crucial to prevent the awkward bends and hunches. Too low? Your erector spinae won’t fully extend, leading to cramping. Too high? Muscles overextend and tug, leading to discomfort and potential injury. Might we suggest a bike fit?

Stretch it Out

Going the aerobars route means you’re a committed cyclist, and commitment means also understanding the importance of balance–body sustainability and aerodynamics. Keeping your body flexible and range of motion adequate can prevent injuries related to aero position.

Muscles produce peak power in the middle range of their length. If you increase the length of your muscles (up to a certain point) through stretching, you’ll have a larger range through which you can produce high power output. There are three key areas where you might be able to improve flexibility to improve riding ergonomics.

Hamstrings: The further you can rotate forward from your pelvis in aero position, the easier it is to maintain a high power output. The ability to easily extend your knees to a ~35 degree angle at the bottom of your pedal stroke prevents your hamstrings from working against you during the downstroke. Stretch this area regularly to create efficiency.

Hip flexors: Hip flexors should not be active on the bike, since they sap energy without contributing to power output. Offloading the hip flexors while riding is key to an efficient pedal stroke. Hip flexors are often tight due to training load and activities of daily life like prolonged sitting. Stretches to loosen up your hip flexors will release this area, allowing the knee to “brush up” against the chest during the upstroke while preventing unwanted muscle activity.

Shoulders: An aero position where arms and hands are closer together is optimal. For this to happen, cyclists need loose deltoids, traps, rhomboids, and pectorals. With a loose upper body, aero position becomes less constrained, and way more comfortable.

Keep comfort in mind when transitioning into aerobars and in deciding when to use them. The severity and length of time in the position you adopt will depend on the event. Consider how it might feel to ride aero on a time-trial bike for one hour versus 4 - 5 hours in an Ironman triathlon. Optimizing performance as well as comfort should be considered.

Physiology of Aero

Reducing drag sounds good in theory, but cyclists really only care about performance. Results trump everything. The goal of minimizing aerodynamic drag is to reduce the power output needed at any given speed, allowing you to use less energy and cycle faster and farther

Metabolic Outcomes

Some studies indicate aero position provides no energetic advantage compared to other cycling positions. One caveat–many of these were conducted indoors! Without wind resistance, aero position requires the same metabolic and ventilatory output as upright and drop positions.4,5,6 Some studies have even shown aerobars increase the metabolic cost of cycling by 1.5 ml/kg/min of oxygen and heart rate by 5 bpm during cycling.7

But, when air resistance is involved (outside, where it really matters), aero position takes the cake. During a outdoor time trial at 30 km/hr, aero position resulted in a lower heart rate (measured by a heart-rate monitor), V02, and ventilatory response in cyclists compared to riding in a standard position. aerobars provided greater efficiency in real-world conditions.

Performance Outcomes

Athletes know even a few watts can translate into huge performance gains.

“You sometimes do funny things even to gain one watt...improvements in nutrition, improvements in position.” - Vittoria Bussi, professional cyclist and HVMN Athlete

In a challenge like the Hour, “kilometers and seconds mean the difference between breaking the record and coming up short.”

Aerobars might just help you find this edge.

Performing well in aero position might be influenced by how much you’ve practiced. When male cyclists unfamiliar with aerobars underwent a steady state and max cycling test using aero position, they used more energy and cycled less efficiently than when in upright position. With a bit of familiarization with aerobars, they might have improved their performance.

Certain models have predicted the theoretical performance change during a 40km time trial while riding aero, concluding that a 5.9% reduction in drag could lead to a seven minute improvement in novice athletes and up to a five minute improvement in trained and elite cyclists.8

Once you learn to properly “get low” and stay comfortable, an aggressive aero position will likely boost cycling speed over a variety of distances. Adopting aero position can increase a cyclist’s max speed by two miles per hour.

Aside from just position, small but significant differences in performance can also come through changes with nutrition. In her UCI hour record, Vittoria Bussi found this extra edge by using HVMN Ketone. Training and using HVMN ketone during her hour record attempt was the result of many months of performance refinement. “When I first tried HVMN ketone in training, the combination of mental lucidity and physical energy was strong and effective” said Bussi. She knew that she wanted to use it during her Hour record attempt, and it paid off.

Power Trade-Offs

Aero position might actually result in a small loss in power output due to the reduced hip angles that can compromise force production. The good news? Any small impairment in force is an acceptable sacrifice for the improvements gained in aerodynamic drag. One study observed an estimated nine-watt loss in mechanical power due to the aero position, but the expected aerodynamic power savings of around 100 watts “far outweigh” the observed metabolic increase.7 Any cyclist will take that trade.

The aerodynamics / power tradeoff at higher speeds resulted in claims that optimal position for speeds over 20mph is an extremely low torso angle,9 i.e. aggressive aero position. The power loss at this speed is acceptable. In real world settings, a performance model based on workload and efficiency is preferred over one solely based on power. Again, whatever produces the best results.

Getting Used to Aerobars

No cyclist is the same. Body shape, weight, height, and width will all determine your adopted position when using aerobars. Expect adjustment to take a while, and don’t rush things.

The two “skis” on aerobars are adjustable, meaning you can change the dimensions of the bars; adjusting them forward, backward, closer together or further apart, and even the angles at which they sit. They’re highly customizable. When you first attach aerobars, don’t completely them on. Hook your bike up to a trainer or something stable and get a feel for the bars while you’re actually on the bike. Once you’ve found the perfect position, lock them in.

Aerobars can be a bit “twitchy” during the first few rides. Hitting a rock or rounding a sharp turn could spell disaster for an aerobar newbie. Practice using aerobars on a wide, flat road until you build up stability and control. To gradually get a feel for the steering, ride for a few minutes tucked into aero position. As you adjust to this new riding style, build up the duration you can ride in aero until it becomes “natural.”

Skills Training

We don’t mean to sound like a broken record, but practice, practice, practice. Several times per week, practice aerobar drills during rides to build confidence and bike control.

Several drills include getting into aero position and back up safely, cornering and descending while in aero, changing gears and braking while in aero and even eating and drinking from water bottles in this position (especially triathletes!). Alternating short periods in aero with upright position also ensures that you’re prepared to change grips in case of an emergency. Since aerobars don’t have gear shifts or brake levers attaching to brake cables, you’ll need to learn how to quickly get your hands to drop position on command.

To Aero or Not to Aero?

You’re serious about cycling but unsure about if aerobars are a good investment. The good news is that aerobars, once installed, can be removed if you find them to be less than desirable. If you do go the way of the aerobars, a few tips might be useful.

Don’t make the mistake of going “full aero” from the start.

Adopting such an aggressive position without giving the body time to adapt is a recipe for injury and chronic pain.

Also, if you use aerobars without the proper training, having an accident becomes more likely.

Riding aero means no shifting and no braking. This makes aerobars particularly tricky for group rides or rides where frequent slowing or stopping occurs. Changing hand positions in close proximity to other cyclists is risky. It might be best to use aerobars for solo fast training rides or time trials on more open roads.

A proper bike fit is a virtual must if you plan to use aerobars. A bike shop can help assess your position, adjust your seat, replace the stem, and alter any other components of your bike to make for a more comfortable and enjoyable ride.

When to Aero

A leisurely ride through the countryside might not be the time to bear down into aero position–you’ll likely receive little benefit. Higher speeds benefit more from aero.

Aero position will surely come in handy for racers, triathletes in particular. Minimizing wind resistance has the obvious benefits of boosting speed, but also lowers energy expenditure on the bike, leaving energy for the run.

Triathletes who minimize wind resistance on the cycle leg improve their subsequent running performance.10 This can also be accomplished through drafting. If you’re in a position to legally draft in a race, this might have similar drag reducing effects to aero position and help to improve performance just as much, without the associated discomfort.

A common mistake riders make is staying in aero position past the point of efficiency. If you dip below 12 mph, you lose most of the benefits.

Are Aerobars Worth the Investment?

If and when to use aerobars requires weighing the potential benefits with the disadvantages.

Is a 1mph - 2mph improvement in your max speed and a bit of a boost to your training rides worth the potential back pain or extra time needed to train to ride aero? Research shows that aerobars work. Aerodynamic gains far outweigh the small hit cyclists may take to power. Will you put in the time to adapt?

Some aerobars run a small price tag. The low risk-investment of aerobars could pay off in speed improvements. With a good amount of training, they may help take your cycling to the next level.

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Scientific Citations

1.Gibertini G, Campanardi G, Grassi D, Macchi C. Aerodynamics of Biker Position. 6th International Colloquium on Bluff Body Aerodynamics & Applications, At Milano, Italy, 2008.
2.Grappe F, Candau R, Belli R, Rouillon JD. Aerodynamic drag in field cycling with special reference to the Obree's position, Ergonomics, 2008. 40:12, 1299-1311.
3.Dorel S, Couturier A, Hug F. Influence of different racing positions on mechanical and electromyographic patterns during pedalling. Scand J Med Sci Sports. 2009;19(1):44-54.
4.Berry MJ, Pollock WE, Van nieuwenhuizen K, Brubaker PH. A comparison between aero and standard racing handlebars during prolonged exercise. Int J Sports Med. 1994;15(1):16-20.
5.Ryschon TW, Stray-gundersen J. The effect of body position on the energy cost of cycling. Med Sci Sports Exerc. 1991;23(8):949-53.
6.Grappe F, Busso T, Rouillon JD. Effect of Cycling Position on Ventilatory and Metabolic Variables. Int. J. Sports Med., 1998; 19, 336 - 341
7.Gnehm P, Reichenbach S, Altpeter E, Widmer H, Hoppeler H. Influence of different racing positions on metabolic cost in elite cyclists. Med Sci Sports Exerc. 1997;29(6):818-23.
8.Jeukendrup AE, Martin J. Improving cycling performance: how should we spend our time and money. Sports Med. 2001;31(7):559-69.
9.Fintelman DM, Sterling M, Hemida H, Li FX. Optimal cycling time trial position models: aerodynamics versus power output and metabolic energy. J Biomech. 2014;47(8):1894-8.
10.Hausswirth C, Lehénaff D, Dréano P, Savonen K. Effects of cycling alone or in a sheltered position on subsequent running performance during a triathlon. Med Sci Sports Exerc. 1999;31(4):599-604.
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