Fast Talk, ep. 30: Myth Busters: Why we can’t talk about lactic acid

The VeloNews Fast Talk podcast is your source for the best advice and most interesting insight on what it takes to become a better cyclist. Listen in as VeloNews columnist Trevor Connor and editor Caley Fretz discuss a range of topics, including training, physiology, technology, and more.

Ouch, it burns! But what is “it” — the root cause of the pain in your legs when you smash it up a hard climb? For the longest time, we colloquially called “it” lactic acid. It turns out that was wrong.

Coach Trevor Connor and Caley Fretz examine the chemistry that occurs in our muscles while riding and racing. They talk to Dr. Iñigo San Millán, who is the director of Colorado University’s exercise physiology lab. Best of all, they give you practical advice for your own training to help make that burn go away — or at least make you faster even if it hurts.

Fast Talk is available on all your favorite podcast services, including iTunes, Stitcher, Google Play, and Soundcloud. If you enjoy the podcast, please consider taking a moment to rate and comment on iTunes after listening. Also, check out the VeloNews Cycling Podcast, our weekly discussion of the sport’s hottest topics, trends, and controversies.

References:

(Benton, et al., 2008; Bonen, 2001; Cairns, 2006; Gladden, 2001; Green, et al., 2002; Mainwood & Renaud, 1985; Messonnier, et al., 2013; San-Millan & Brooks, 2017; Thomas, Bishop, Moore-Morris, & Mercier, 2007; Thomas, Bishop, Lambert, Mercier, & Brooks, 2012; van Hall, 2010)

Benton, C. R., Yoshida, Y., Lally, J., Han, X. X., Hatta, H., & Bonen, A. (2008). PGC-1alpha increases skeletal muscle lactate uptake by increasing the expression of MCT1 but not MCT2 or MCT4. Physiol Genomics, 35(1), 45-54. doi: 10.1152/physiolgenomics.90217.2008
Bonen, A. (2001). The expression of lactate transporters (MCT1 and MCT4) in heart and muscle. Eur J Appl Physiol, 86(1), 6-11. doi: 10.1007/s004210100516
Cairns, S. P. (2006). Lactic acid and exercise performance : culprit or friend? Sports Med, 36(4), 279-291.
Gladden, L. B. (2001). Lactic acid: New roles in a new millennium. Proc Natl Acad Sci U S A, 98(2), 395-397. doi: 10.1073/pnas.98.2.395
Green, H., Halestrap, A., Mockett, C., O’Toole, D., Grant, S., & Ouyang, J. (2002). Increases in muscle MCT are associated with reductions in muscle lactate after a single exercise session in humans. Am J Physiol Endocrinol Metab, 282(1), E154-160.
Mainwood, G. W., & Renaud, J. M. (1985). The effect of acid-base balance on fatigue of skeletal muscle. Can J Physiol Pharmacol, 63(5), 403-416.
Messonnier, L. A., Emhoff, C. A. W., Fattor, J. A., Horning, M. A., Carlson, T. J., & Brooks, G. A. (2013). Lactate kinetics at the lactate threshold in trained and untrained men. [Article]. Journal of Applied Physiology, 114(11), 1593-1602. doi: 10.1152/japplphysiol.00043.2013
San-Millan, I., & Brooks, G. A. (2017). Reexamining cancer metabolism: lactate production for carcinogenesis could be the purpose and explanation of the Warburg Effect. [Review]. Carcinogenesis, 38(2), 119-133. doi: 10.1093/carcin/bgw127
Thomas, C., Bishop, D., Moore-Morris, T., & Mercier, J. (2007). Effects of high-intensity training on MCT1, MCT4, and NBC expressions in rat skeletal muscles: influence of chronic metabolic alkalosis. Am J Physiol Endocrinol Metab, 293(4), E916-922. doi: 10.1152/ajpendo.00164.2007
Thomas, C., Bishop, D. J., Lambert, K., Mercier, J., & Brooks, G. A. (2012). Effects of acute and chronic exercise on sarcolemmal MCT1 and MCT4 contents in human skeletal muscles: current status. Am J Physiol Regul Integr Comp Physiol, 302(1), R1-14. doi: 10.1152/ajpregu.00250.2011
van Hall, G. (2010). Lactate kinetics in human tissues at rest and during exercise. [Review]. Acta Physiologica, 199(4), 499-508. doi: 10.1111/j.1748-1716.2010.02122.x

The post Fast Talk, ep. 30: Myth Busters: Why we can’t talk about lactic acid appeared first on VeloNews.com.

Diagnosis: How to fine-tune diet for racing

Ellie was a 23-year-old professional triathlete who was preparing for the Ironman 70.3 World Championships in 2016. Like many athletes, Ellie believed she could improve her race performance by refining her body composition and pre-race fuel strategy. Both of these goals meant she’d need to change her diet. Ellie was unsure of how to do this without hurting her training or her taper for the big day.

Ellie posed this challenge to Ryan Kohler, manager of sports performance at the University of Colorado Sports Medicine and Performance Center. Kohler had already worked with Ellie for 1.5 years and knew she possessed disciplined eating habits.

How does an elite athlete refine her diet without impacting performance?

The two needed to devise a hyper-focused diet that maximized glycogen stores leading up to her race, without negatively impacting body composition or weight. The pair also needed to determine the appropriate timing and amount of carbohydrates to include in her diet, while allowing for her caloric needs and adjusting for her taper.

“It was just a matter of including additional objectives to focus her nutrition around specific times of the season,” Kohler says.

Tests

Kohler and his team initially performed a skinfold body-composition measurement and gathered body weight and food-log information. Then, they used MuscleSound software to accurately and non-invasively determine Ellie’s stored carbohydrate. MuscleSound was co-developed by Dr. Iñigo San Millan, the director of the Performance Center and a prominent physiologist with decades of experience working with professional cyclists.

It works in conjunction with a portable ultrasound device to calculate relative glycogen concentration, tissue thickness, body fat percentage, and lean mass. It does this by automatically detecting fat-muscle boundaries. If you imagine your muscles as fuel tanks, the ultrasound allows you to see how much gas is in the tank.

The rectus femoris muscle was used as the measurement site. Studies in endurance athletes have shown this muscle provides a good assessment of lower-body storage, and can reflect small to large changes due to nutrition, training, or recovery interventions.

The MuscleSound test revealed Ellie was approximately 70 percent “full,” meaning she was adequately storing carbohydrates for her daily training needs, and she had additional room to super-compensate — in this case for the priority event.

Intervention

Kohler prescribed a carb-rich diet, slightly above what Ellie was accustomed to eating. She tried the new meal plan for one week, and combined specific food suggestions. For example, she ate things such as oats, yogurt, and egg whites for breakfast; lunch might include a deli sandwich and salad; and dinner could be fish, sweet potatoes, and broccoli.

Then, Ellie spent a week eating whatever she wanted, so long as it supported her training, was low in fat, and allowed for maximal carbohydrate storage. She ate 2,600 kilocalories per day, broken down into six grams per kilogram of carbohydrates and 1.7-1.9 grams per kilogram of protein.

Ellie maintained her total caloric intake (while reducing fat intake) by consuming additional calories from (1) carbohydrates, to support training and provide additional substrate for glycogen re-synthesis; and from (2) protein to support recovery and increase satiety in the absence of additional fat. Kohler focused the timing of Ellie’s carbohydrate doses to provide the additional energy when necessary.

Results

Ellie followed the experimental diet for one week. Then her glycogen stores were retested under the same conditions. The ultrasound revealed that her proverbial fuel tank was at 90 percent of its glycogen capacity (which Kohler considered to be near the maximum attainable), and she reported having increased energy levels. Over the one-week trial, Ellie also experienced a one percent decline in body weight and five percent decline in body composition.

Because the test was conducted five weeks prior to worlds, Kohler returned Ellie to her usual training diet to allow carbohydrate levels to return to normal.

The week before her big race, Ellie went back on the carb-rich diet. She finished 11th at the world championships.

The post Diagnosis: How to fine-tune diet for racing appeared first on VeloNews.com.

Book excerpt: Four heart health warning signs

Editor’s note: The following is an excerpt from the new VeloPress book,“The Haywire Heart” by Chris Case, Lennard Zinn, and Dr. John Mandrola.

When Lennard Zinn’s heart began to flop like a fish in his chest while riding up Flagstaff Mountain above Boulder, Colorado, his first reaction was simple: “I went into denial.” He shouldn’t have. His heart rate jumped from 155 to 218 beats per minute and stayed pegged there. As detailed in the preface to “The Haywire Heart” and previous articles on VeloNews, Zinn ultimately received a life-changing diagnosis: multifocal atrial tachycardia.

If his case has any instructive use, it should be to demonstrate that there are plenty of warning signs of trouble. The key is to heed them. But what are they? And what should you be looking for in yourself?

There are two types of symptoms to worry about. Both fall into the category of “not normal.” Your immediate sensations are a good guide. You have probably been training for many years, if not most of your life. Those years of training have given you a good sense of what “normal” feels like. What you are looking for is anything that falls outside the boundaries of normal. For example, a brief flutter in your chest on a ride is probably nothing; nearly everyone gets one from time to time. A flutter that won’t go away, however, is cause for concern. A sustained irregular heartbeat is an abnormal feeling that should set off an alarm.

Four warning signs:

1. Racing heart: any sustained racing of the heart that won’t go away.

2. Chest pressure or pain, especially pressure or pain that worsens during exertion.

3. Labored breathing: difficult breathing that is out of proportion to effort (everyone breathes hard when climbing hills or sprinting).

4. Fainting or near-fainting: anything more serious than the everyday lightheadedness you might feel after a hard effort.

These symptoms are serious warning signs that should alert you to possible trouble. Sustained chest pressure or chest pain warrants a call to 911.

All others warrant an appointment with your doctor, sooner rather than later. If you experience these symptoms, you should stop training until you can be evaluated by a professional.

Be warned that many doctors just don’t get athletes, even if they themselves are active exercisers. Many doctors just don’t understand the duration and intensity of workouts and races for endurance athletes. Doctors actually tend to over-diagnose heart conditions in athletes — simply because they are not accustomed to the slow and strong heart beats, high electrocardiogram signals, and enlarged hearts that are often normal for endurance athletes. For women, talking to your doctor is especially important; women under 55 are actually seven times more likely to be misdiagnosed or turned away at the ER.

The bottom line:

Call 911 immediately if you have sustained chest pressure or chest pain.

If you experience the “not normal” sensations listed above, stop exercising and schedule an appointment with your primary care physician.

Before you see your doc, read “The Haywire Heart” so you are prepared for your appointment.

Sharing is caring. Please consider sharing this article with your athletic friends so they might avoid heart problems or catch them before they worsen.

The post Book excerpt: Four heart health warning signs appeared first on VeloNews.com.

Fast Talk podcast, ep. 26: Cramping myths debunked

The VeloNews Fast Talk podcast is your source for the best advice and most interesting insight on what it takes to become a better cyclist. Listen in as VeloNews columnist Trevor Connor and editor Caley Fretz discuss a range of topics, including training, physiology, technology, and more.

For decades (almost a century, in fact), we’ve been told that cramping is caused by electrolyte imbalance or bad hydration. But new science suggests that this probably isn’t why you cramp during exercise.

So why do you cramp? It all comes down to something called altered neuromuscular control. And how do you stop it? Well, that’s where things get even trickier. Listen in to find out.

Fast Talk is available on all your favorite podcast services, including iTunes, Stitcher, Google Play, and Soundcloud. If you enjoy the podcast, please consider taking a moment to rate and comment on iTunes after listening. Also, check out the VeloNews Cycling Podcast, our weekly discussion of the sport’s hottest topics, trends, and controversies.

References

Hutton, R. S., & Nelson, D. L. (1986). STRETCH SENSITIVITY OF GOLGI TENDON ORGANS IN FATIGUED GASTROCNEMIUS-MUSCLE. [Article]. Medicine and Science in Sports and Exercise, 18(1), 69-74.
Miller, K. C., Mack, G. W., Knight, K. L., Hopkins, J. T., Draper, D. O., Fields, P. J., et al. (2010). Three percent hypohydration does not affect threshold frequency of electrically induced cramps. Med Sci Sports Exerc, 42(11), 2056-2063. doi: 10.1249/MSS.0b013e3181dd5e3a
Nelson, D. L., & Hutton, R. S. (1985). DYNAMIC AND STATIC STRETCH RESPONSES IN MUSCLE-SPINDLE RECEPTORS IN FATIGUED MUSCLE. [Article]. Medicine and Science in Sports and Exercise, 17(4), 445-450. doi: 10.1249/00005768-198508000-00007
Nelson, N. L., & Churilla, J. R. (2016). A narrative review of exercise-associated muscle cramps: Factors that contribute to neuromuscular fatigue and management implications. Muscle Nerve, 54(2), 177-185. doi: 10.1002/mus.25176
Schwellnus, M. P. (2009). Cause of exercise associated muscle cramps (EAMC)–altered neuromuscular control, dehydration or electrolyte depletion? Br J Sports Med, 43(6), 401-408. doi: 10.1136/bjsm.2008.050401
Schwellnus, M. P., Allie, S., Derman, W., & Collins, M. (2011). Increased running speed and pre-race muscle damage as risk factors for exercise-associated muscle cramps in a 56 km ultra-marathon: a prospective cohort study. Br J Sports Med, 45(14), 1132-1136. doi: 10.1136/bjsm.2010.082677
Schwellnus, M. P., Derman, E. W., & Noakes, T. D. (1997). Aetiology of skeletal muscle ‘cramps’ during exercise: a novel hypothesis. J Sports Sci, 15(3), 277-285. doi: 10.1080/026404197367281
Schwellnus, M. P., Drew, N., & Collins, M. (2011). Increased running speed and previous cramps rather than dehydration or serum sodium changes predict exercise-associated muscle cramping: a prospective cohort study in 210 Ironman triathletes. Br J Sports Med, 45(8), 650-656. doi: 10.1136/bjsm.2010.078535
Shang, G., Collins, M., & Schwellnus, M. P. (2011). Factors associated with a self-reported history of exercise-associated muscle cramps in Ironman triathletes: a case-control study. Clin J Sport Med, 21(3), 204-210. doi: 10.1097/JSM.0b013e31820bcbfd
Wagner, T., Behnia, N., Ancheta, W. K., Shen, R., Farrokhi, S., & Powers, C. M. (2010). Strengthening and neuromuscular reeducation of the gluteus maximus in a triathlete with exercise-associated cramping of the hamstrings. J Orthop Sports Phys Ther, 40(2), 112-119. doi: 10.2519/jospt.2010.3110

The post Fast Talk podcast, ep. 26: Cramping myths debunked appeared first on VeloNews.com.

Fast Talk, ep. 24: Surviving a long season like a pro

The VeloNews Fast Talk podcast is your source for the best advice and most interesting insight on what it takes to become a better cyclist. Listen in as VeloNews columnist Trevor Connor and editor Caley Fretz discuss a range of topics, including training, physiology, technology, and more.

Is it possible to stay fit and fast all year round? We talk to former pro and team director Mike Creed about the toll that cycling takes on a body. He also discusses the mentality required to endure bad days on a bike, which happen far more often than good days. Plus, we speak with Cannondale-Drapac pro Toms Skujins and Trek-Segafredo pro Kiel Reijnen about how they plan their seasons, schedule training and avoid the dreaded burn-out.

This episode of Fast Talk is presented by Quarq.

Fast Talk is available on all your favorite podcast services, including iTunes, Stitcher, Google Play, and Soundcloud. If you enjoy the podcast, please consider taking a moment to rate and comment on iTunes after listening. Also, check out the VeloNews Cycling Podcast, our weekly discussion of the sport’s hottest topics, trends, and controversies.

The post Fast Talk, ep. 24: Surviving a long season like a pro appeared first on VeloNews.com.