Joe Friel

More on Bone Health

About two weeks ago I posted here showing that cyclists may experience a loss of bone minerals possibly resulting in brittle bones and an increased likelihood of breaks. I mentioned then that I would get back to the topic relative to prevention and treatment. Since then I’ve been reading the scientific literature on the topic. There’s a ton of it, far more than I can possibly cover here. But fortunately, Dr. John Post, TrainingBible Coaching’s Medical Director, is also running a series on bone health on his blog.  So I’m going to back off and let him discuss the medical details as that is certainly more in his realm of expertise than mine. Related topics include the effects of aging, hormones, diet, gender, vitamin D and more. So instead I’m going to post one last blog on the prevention of osteopenia and osteoporosis from an exercise point of view.

If cycling seems to have negative consequences for bone health are there other activities; such as weight lifting, running, swimming and walking; that are more beneficial? Below I pose several related questions and searched PubMed for answers.

I use the word “answers” somewhat liberally as there rarely is a definite answer from research studies. When dealing with humans there are many variables that can’t be controlled. And different protocols may produce different results. So one study by itself is seldom an “answer.” The more studies there are on a complex topic such as this one the better the direction – usually. But bear in mind that studies with similar protocols and subjects have been known to produce exactly the opposite results.

So here are 10 questions, a brief summary of the related research and the “answers.” (If you want to dig deeper, click on the study citation and it will take you to the abstract at PubMed so you can read more details for yourself.)

Question #1: Does running improve bone health?

Wilks DC, Winwood K, Gilliver SF, Kwiet A, Sun LW, Gutwasser C, Ferretti JL, Sargeant AJ, Felsenberg D, Rittweger J. 2009. Age-dependency in bone mass and geometry: a pQCT study on male and female master sprinters, middle and long distance runners, race-walkers and sedentary people. J Musculoskelet Neuronal Interact. 9(4):236-46. 

Study Summary: Male and female runners aged 33-94 years had greater tibial (shin) bone strength than sedentary controls of the same age. But the runners also lost bone with advancing age. There was no difference in the radius bone (forearm) between runners and sedentary controls.

Answer: Running appears to make the tibia stronger but there is still a loss of leg bone density with aging in runners. Running did not improve an arm bone health.

Question #2: Is there an activity which is even better for bone health than running?

Suominen H. 1993.Bone mineral density and long term exercise. An overview of cross-sectional athlete studies. Sports Med. 16(5):316-30. 

Study Summary: This is a 1993 review of the scientific literature on the topic. Reviews make my job a bit easier since the author of a review has selected good (usually) studies and done the legwork by compiling and analyzing the data from all. This review reports that the strongest bones have typically been found in power- and strength-trained athletes. “Endurance activities such as long distance running and swimming seem less effective with regard to peak bone density.”

Answer: It appears that lifting weights and participating in power activities (sprinting, jumping, bounding, etc) are more effective than running for bone health.

Question #3: That’s an old study. Is there anything newer?

Suominen H. 2006. Muscle training for bone strength. Aging Clin Exp Res. 18(2):85-93.

Study Summary: From the same author as above only 13 years later, this is a review of the scientific literature looking for the best types of activity for improving bone health. In summary, he says that although aerobic exercise is important in maintaining overall health, a heavy-load, resistance type of muscle training may be better for bone health.

Answer: Yep. Looks like weight training is better for bone health than running.

Question #4: Are you sure lifting weights is better than running? I hate going to the gym.

Layne JE, Nelson ME. 1999. The effects of progressive resistance training on bone density: a review. Med Sci Sports Exerc. 31(1):25-30. 

Study Summary: This is another review to keep me having to work too hard. To quote the authors: “Both aerobic and resistance training exercise can provide weight-bearing stimulus to bone, yet research indicates that resistance training may have a more profound site-specific effect than aerobic exercise. Over the past 10 years, nearly two dozen cross-sectional and longitudinal studies have shown a direct and positive relationship between the effects of resistance training and bone density.”

Answer: There seems to be little doubt that lifting weights is effective for bone health and may be the most effective activity.

Question #5: What about swimming?

Guadalupe-Grau A, Fuentes T, Guerra B, Calbet JA. 2009. Exercise and bone mass in adults. Sports Med. 39(6):439-68

Study Summary: This is a review of studies prior to 2009 regarding exercise in maintenance of bone health. This is yet another review showing that exercise activities with high forces (for example, weight lifting) or high impacts (for example jumping and bounding) have the greatest potential for maintaining bone strength. Not all types of exercise have shown positive effects on bone. For example, swimming has no impact on bone mass, while walking has limited positive effects. Exercise involving high impacts, even a small amount, seems to be the most efficient for building bone mass.

Answer: It looks like pushing off the wall of the pool will not build stronger bones.

Question #6: I’m a cyclist and can’t run due to a bad knee. Should I walk instead?

Martyn-St James M, Carroll S. 2008. Meta-analysis of walking for preservation of bone mineral density in postmenopausal women. Bone. 43(3):521-31.

Study Summary: “Regular walking has no significant effect on preservation of BMD at the spine in postmenopausal women, whilst significant positive effects at femoral neck are evident.” Insufficient data was available for the hip.

Answer: The subjects in this study were postmenopausal women, so this may not apply across the board to premenopausal women or to men. However, the research on exercise generally supports the notion that impact is critical in aerobic exercise for bone health. That’s why cycling scores so poorly. The impact forces of walking are much less than that of running and so the effect for those other than postmenopausal women is probably about the same.

Question #7: What if I run more miles? Will that help build bone?

Deriaz O, Najafi B, Ballabeni P, Crettenand A, Gobelet C, Aminian K, Rizzoli R, Gremion G. 2010. Proximal tibia volumetric bone mineral density is correlated to the magnitude of local acceleration in male long-distance runners. J Appl Physiol. 108(4): 852-7.

Study Summary: Subjects were tested for tibial (shin) bone strength over a 3-year period. Those who ran more than 30km per week (three groups of subjects ran 5-30, 30-50 or 50-100km per week) had the strongest bones. And the greater the heel strike force the stronger the tibial health.

Answer: Running with higher volume seems to help maintain bone and 30km per week was the threshold for these subjects.

Question #8: If running more is good would doing ultra-running events be the way to go?

Kerschan-Schindl K, Thalmann M, Sodeck GH, Skenderi K, Matalas AL, Grampp S, Ebner C, Pietschmann P. 2009. A 246-km continuous running race causes significant changes in bone metabolism. Bone. 45(6):1079-83.  

Study Summary: A 246-km continuous running race caused significant negative changes in bone health in 18 runners who were subjects. Tests were conducted before, after and 3 days after the race. Bone mineral was lost and bone formation was suppressed afterwards.

Answer: Unfortunately, this study says that doing ultra-distance running races is not beneficial, at least during and in the three days afterwards. I found no studies that did a longer analysis of ultrarunners’ bone health.

Question #9: Since impact force appears to be good for bone, would running faster help?

Wilks DC, Winwood K, Gilliver SF, Kwiet A, Chatfield M, Michaelis I, Sun LW, Ferretti JL, Sargeant AJ, Felsenberg D, Rittweger J. 2009. Bone mass and geometry of the tibia and the radius of master sprinters, middle and long distance runners, race-walkers and sedentary control participants: a pQCT study. Bone. 45(1):91-7. 

Study Summary: In this study tibial (shin) bone strength indicators seemed to be related to impact forces (heavy foot strikes). The faster the subjects ran (for example, sprinters vs. distance runners) the stronger the tibia.

Answer: Yes, running faster does seem to be beneficial for bone health. This may not mean running “faster” relative to your best effort, but faster relative to absolute speed. In other words, running really fast, as a sprinter does, is probably key here, not running 8-minute mile pace instead of 9-minute mile pace (although that may help a small amount). Of course, it could just be that having poor technique, running on concrete and wearing thin-soled shoes (or no shoes) is good for bone strength. But I don’t think I’d go these routes just to build up your bones. A better alternative may be to do plyometric exercises or rope jumping.

Question #10: Will trying to lose a few pounds by eating less and running more cause a problem with bone health?

Pollock N, Grogan C, Perry M, Pedlar C, Cooke K, Morrissey D, Dimitriou L. 2010. Bone-mineral density and other features of the female athlete triad in elite endurance runners: a longitudinal and cross-sectional observational study. Int J Sport Nutr Exerc Metab. (5):418-26. 

Study Summary: Female, college distance runners who chronically trained at a high volume and did not eat enough to replace calories burned during exercise experienced menstrual dysfunction and bone loss.

Answer: It appears, at least for young women, that eating less and running more over a long period of time is dangerous for bone health.

In Conclusion: I don’t plan to come back to this topic again in the near future unless new research on the topic appears in the scientific literature. So for now, here is what we seem to know about exercise and bone health. It appears the best thing you could do is lift weights. The next best option is exercise that involves high impact such as plyometrics (which has also been shown effective for cycling and running performance). Running, especially more than 30km (18.6 miles) per week, is also effective. Walking may have a limited benefit. Swimming probably has no bone-health benefit.

Quality Training

In the Build period focus on key workouts, not weekly volume numbers. Quality, not quantity, determines performance now.

I posted the above comment to my Twitter account yesterday and got a response from a follower: “What is quality training?” Good question. That’s one which gets at the heart of periodization. I like Twitter but answering complex questions with 140 characters is not easy. This one takes a few more. Let’s start by putting things in perspective.

Training quantity is simple. It’s just how many miles, kilometers, hours, meters, yards, TSS or kilojoules done in a week. Your volume. All you need is an adding machine. This is the focus of the Base period – accumulating general fitness by doing lots of non-specific training. “Non-specific” means the workouts aren’t necessarily like the events for which you are training. For example, you may be lifting weights. At no pint in your races this summer will you have to stop and pound out a few squats. Weight lifting is non-specific. Drills to improve technique are non-specific since you don’t do them during a race. In the Base period you may be training on hills even though the race courses are flat. Another non-specific.

Here’s one that is a subtle variation on this theme. Training at an intensity that is not race goal pace or power is non-specific. That means going well above or below race pace or power. Training intensity is where athletes tend to get confused about periodization.

Periodization of intensity does not mean going really slow in the Base period and then going faster and faster each week in the Build period. It doesn’t work that way.

While the purpose of the Base period was general fitness, the purpose of the Build period is specific fitness. This involves individual workouts that simulate the intensity and the duration of your next A-priority race. You can stop being concerned with volume at this point. If you did a good job of raising it during the Base period then you can maintain it quite easily now. In fact, in the Build period it’s not unusual for volume to be reduced a bit as the focus shifts to unique training sessions. If you are an experienced athlete whose goal is to perform at a high level relative to your ability then continuing to increase volume will not give you the desired results. Quality training will.

Once again: Quantity is not the key to performance; quality is.

So that brings us back to where we started: What is quality training? You should have a pretty good idea of how to answer this now. Quality training involves doing workouts that simulate the intensity and the duration of your goal race (and other unique variables such as race terrain). Some of the Build period workouts will focus on the specific intensity. Others will focus on the specific duration. The highest quality workouts will include both specific intensity and specific duration.

Workouts for specific intensity only or specific duration only are simple to do. It’s the third category which is the most challenging. Combining them makes for a very difficult, but very affective workout. How you do that depends on the event for which you are training. For example, road cyclists training for a road race will typically do a fast group ride of about race duration. An Ironman triathlete may do a Big Day of training involving a long swim, long bike and long run with each done at race intensity (I have IM triathletes rest for 90 minutes between each leg of this workout). A marathon runner may do a 20-miler with the last 8 miles at race pace. Another option with this specificity goal in mind is to do a low-priority race in the Build period. The details of this race (distance, terrain, weather, pacing, etc) all need to be considered relative to your limiters and your A-priority race.

So that’s quality. I hope this sinks in as it’s the single most misunderstood area of periodization. If you understand and apply it in the last 12 weeks before your race then the chances of having a successful race are greatly improved.

High Heart Rate Questions

I receive lots of questions from athletes every week. They seem to come in topical groups. For some unknown reason this spring I’ve gotten a lot of questions from athletes who believe their heart rates are abnormally high during exercise and imply that they are concerned that they may have a cardiovascular problem. One guy even recently wondered why his heart didn’t explode. I don’t know if he was kidding but it’s the sort of thing many seem to be wondering this spring. So rather than continuing to reply to this same question repeatedly I thought I’d simply answer it here and then refer people to it when they query me. I also asked Dr. John Post, an old friend of mine and the Medical Director for TrainingBible Coaching, to comment from a medical perspective. He and I separately wrote a general reply. They seem to overlap quite a bit. So, here we go…

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Joe:

The first matter is to understand what “high” heart rate means. High relative to what? If it’s high referenced against the formula 220 minus your age then realize that this is seldom correct for anyone. If we found the max heart rates of a large group of people and graphed them we’d more than likely get a bell-shaped curve. There would be a lot of people in the middle for whom the formula was close, there would be some to the left end for whom the formula was too high (low normal heart rates), and to the right end of the curve would be those for whom the formula was too low (high normal heart rates). For people on the right end of the curve, chronically “high” heart rates while exercising are normal. They don’t have a problem, at least not based strictly on their heart rates.

Or if “high” heart rate means it’s high relative to your training partners' then this is essentially the same matter as the 220-minus-age formula. If this defines “high” then, in the absence of any other symptoms (such as light headed; nauseous; pressure, pain or discomfort in chest, arm, neck or jaw), you are probably good to go. You don’t have a problem. You just are on the right end of the bell-shaped curve.

These normal high or low heart rates also have no bearing on performance. I once coached a US National Age Group Time Trial Champion who broke the record for his age group. His 20k time trial heart rate was around 145. This didn’t slow him down. I also once coached a runner with a max heart rate in the high 210s. I’ve also coached athletes with big feet and little feet. None of these athletes had problems. They were just unique.

However, if the high exercising heart rate is unusual for you then you may indeed have a problem. But let’s further define “high” here. There are going to be days when your heart rate rises above what you normally see by perhaps 10 bpm or slightly more just because of fatigue, overreaching, overtraining, too much caffeine or similar product, or a hot day. This is not unusual at all. You may need to back off and slow down or even abandon the workout that day. This happens to everyone from time to time.

But if your heart rate is well above 10bpm over what you normally see at a given power, pace or perceived exertion (which may not work in this case) then you could have a health problem. But first check to make sure your heart rate monitor is working correctly and there are no errant signals.

Such an unusually high heart rate happened to me in 1994 while running a half marathon. Of course, as the dummy I am, I finished the race, albeit at a slower pace. After weeks of testing my doctor finally determined it was a case of viral myocarditis. That cost me seven months of training.

Another condition to be aware of is atrial fibrillation (“a-fib”). I won’t go into detail on this as you can read more about this here on Dr. Post’s blog. 

So if you mean a “high” heart rate as one high relative to what you normally see at an otherwise common intensity and you’ve ruled out the heart rate monitor as the source of the “problem,” then see your doctor.

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John Post, MD:

Joe and I have received a number of queries recently about heart rate related issues observed in training so I thought a review may help answer some of these.  This is a pretty broad topic so I’ll try to be brief.  Let’s try to work from the answer backwards:

1)     No two of us are the same.

2)     No two of us fit the exact same formula/parameters relating heart rate to training.

3)     If I see an unexpected indication, am I symptomatic?

“Balderdash,” you say.  You’ve memorized the Triathlete’s/Cyclists’s Training Bible, understand the Borg scale of perceived exertion, and have constructed reproducible training zones.  One initial fact that surprises many is that although your “athlete’s heart” resting pulse is probably around 60 or below, according to the Mayo Clinic, a normal resting heart rate can be 60 – 100.  Yes, 100!  And those of you on beta blockers as a part of your hypertension regimen will note a modest lowering of your natural base rate.

We athletes as a group pay a lot more attention to our bodies in general and HR in particular.  And as such we should be familiar with the factors, in addition to exercise, that can modify our expected read out.  Examples would be lack of sleep, fever, dehydration, anxiety, coffee (which you already know and manipulate), stress, general state of rest, just to name a few.  Each of these could significantly alter that old Polar.

So, if you’re out on a routine training run over familiar territory you see a reading of 220, what do you do?

1)     Use the old formula, 220 minus your age, and determine that you are dead?

2)     Start self CPR?

3)     Flag down a passing motor vehicle for a ride to the hospital?

4)     Panic, wonder if your affairs and will are in order?

5)     Call 911?

6)     Rush home, post the symptoms on an internet forum and wait for guidance from an anonymous source?

7)     Stop, think, and reasonably evaluate the situation?

Let’s use the scientific approach.  If you’re symptomless, there’s no rush to do anything.  An old saw from medical school is when you encounter an emergency situation, “Take your own pulse first.” If you’re not dizzy, in pain, feeling weak – especially on one side of the body, confused, etc. you have the ability to rationally evaluate what’s going on and exercise common sense.

It’s not uncommon to see what seems like bogus information be indeed bogus.  Was this erratic reading due to nearby electrical interference, overhead power lines, nearby welding, lead placement or slippage, etc.? It’s unlikely that even if you were running with Kim Kardashian (ladies with Johnny Depp) that you could generate a heart rate of 220.

If, however, you do experience symptoms, or if it happens again, seek medical attention.

Aerodynamic Head Position in Cycling

I'm taking a brief break from brittle bones to write about other topics. My next posts on bone health will have to do with what the reserahc suggests is effective. Turnsa out that there is a lot of research to read on this topic. In the mean time, the Paris-Nice stage race is being contested in France and Versus television is covering it here in the States.

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Last night I watched the March 11 Paris-Nice Time Trial which Tony Martin (HTC-Highroad) won taking the yellow leader’s jersey from Andreas Kloden (Radioshack). I have no way of knowing for sure, but I suspect the difference (46 seconds) between the two finishing times was more a result of aerodynamics than power.

It’s obvious that Martin has devoted a good deal of time to getting his position dialed in. Even though Kloden’s back is much flatter, Martin’s rounded back is not a problem. The wind will be escorted over it and off the trailing edge rather smoothly. The thing that Martin does best, however, is keeping his head out of the wind. This isn’t easy to do but the pay off is significant. I’ve written about this before (Feb 2007, Feb 2010, December 2010).

The accompanying pictures were taken from the television and so are a bit blurry (click to enlarge). The first is a sideview of Martin showing his rounded back. The second is of Kloden. Kloden’s much flatter back is evident. But in these two pictures notice how much lower Martin’s head is. A high head position could slow a rider by more than 1%. The difference of 46 seconds amounts to 2.24% of Kloden’s time.

To get your head into the position Martin has his in in the above picture requires pointing your nose almost straight down and then rolling the eyes up as if looking over your sunglasses. This takes some getting used to. Both your neck and your eyeballs will fatigue unless you do it frequently. They can be trained just as your legs are. Here in the third picture you can see a picture of Jani Brajkovic (Radioshack), another excellent time trialist, in a head-on shot. Notice that his chin is below his chest and that the top of his helmet is about even with the top of his back. He’s looking “over the top of his sunglasses.”

But Martin did something else, mostly early in the race, that I believe reduces drag even more. He further lowered his head and looked straight down at the ground briefly 10 or more times a minute. This further reduces the drag created by the head as it is then completely below the back. The small helmet tail sticking up creates insignificant drag compared with the much larger head in the lowered position reducing drag significantly. You can see a picture of it here. My December visit to the Fort Collins, Colorado wind tunnel, along with the guys from PowerTri, suggested that this head-lowered position saves another 1% or more. I never saw Kloden look down once. He kept his head in what is considered to be the traditional time trial position as best he could as shown in the last picture.

Be aware that looking down is dangerous. A friend of mine has been in a wheelchair since 1987 because he was riding in this position and ran into a vehicle. The way Martin did it was perfect. He looked down for just a second or two at a time but did it repeatedly. The best times to do this are when you are going downhill or into a strong head wind.

Also, getting your head into the below-the-back aero position (not even the more aggressive head-down-helmet-tail-up position) is not going to work for everyone. The longer your time trial the more challenging this becomes. For example, in a half or full Ironman-distance race the very aggressive position used by any of these three riders is probably not going to work. Neck, back and eyeball fatigue will be too great causing you to come out of the aero position repeatedly, especially later in the race. That will “cost” you more time overall than simply having a more comfortable position. It may even be overly challenging for races lasting an hour or so. But if you’re time trialing for less than an hour and you need to shave a few more seconds off of your time to be competitive then you might give it a try. That requires training on your TT/tri bike frequently working on position.

The starting place for this is a bike fit by a professional fitter. Making changes to your position to become more aero without taking into consideration how those changes affect the other aspects of your pedaling technique and position is as likely to slow you down as to speed you up.

CU Looking for Bone Study Subjects

There is a research study going on at the University of Colorado regarding bone density in cyclists.  Nanna Meyer, PhD, is leading the project and is looking for  high-caliber cyclists in Colorado to be subjects.  Dr. Meyer tells me that the qualifications to participate are...

• Between 18-50 yrs of age
• Male or female
• Cat 1, 2, or 3 cyclist
• Interested in optimizing your bone health
• Interested in learning about nutrition

The requirements include 2 testing sessions at the University of Colorado at Colorado Springs (bone mineral density and body composition testing using Dual Energy X-ray Absorptiometry [DXA] and vertical jump assessment), virtual 4-month online interaction using TrainingPeaks Software for nutrition and training, and 3 blood tests aimed at assessing vitamin D status and energy levels at any of Centura Health Lab locations in Colorado.

If you fit the qualifications listed above, please contact sports dietitian and professor Nanna Meyer, PhD, RD, CSSD at nmeyer2@uccs.edu.

Bones and Cyclists

Although we tend to associate brittle bones with women older than age 65, it can also occur in men. And you don’t have to be “old” to experience it. When my son, Dirk Friel, was 29 (he’s now 40) he was tested for bone health at the University of Colorado by Alan Lim, now the exercise physiologist with team RadioShack, and was told that some his bones were like those of a 60-year-old man. Brittle. Interestingly, he had been training for road bike racing since he was 12. As he became older and moved into the pro ranks he did less and less physical activity other than ride a bike. Could riding a bike have contributed to his poor bone mineral density? If so, is this a problem for road cyclists in general? The answer to both questions appears to be "yes."

Bone mineral density (BMD) is a measure of how much mineral, such as calcium, you have in your bones. It is most commonly measured in a selected bone by using a DEXA (dual energy x-ray absorptiometry) scan.  There are other methods also used. The results of such testing are scored for risk of a broken bone in a fall or other sudden impact. Those at the highest risk are termed “osteoporotic.” An early stage of osteoporosis is called “osteopenia.”

In recent years there have been a number of studies showing that osteoporosis and osteopenia may well be associated with riding a bike. A quick check of PubMed found the following recent studies, most of which seem to support this possibility. There are some very interesting conclusions here for road cyclists, mountain bikers, triathletes and runners. Following the citation for each study is the quoted conclusion from the authors followed by my comments.

Nichols JF, Rauh MJ. 2011. Longitudinal changes in bone mineral density in male master cyclists and nonathletes. J Strength Cond Res 25(3):727-34.

STUDY CONCLUSION: “The high percentage of male master cyclists with low BMD, combined with a high risk for fracture from falls associated with competitive cycling, warrant attention among this population. Coaches and health professionals interacting with cyclists need to promote alternative exercise such as weight training, plyometrics, or other high impact activity as a complement to cycle training to help minimize bone loss in this population.”

COMMENTS: This study followed 19 competitive road cyclists and 18 non-athletes for 7 years. All were over 35 years of age. At the start of the study 84% of the cyclists met the criteria for osteopenia or osteoporosis (50% of the non-athletes). Seven years later 90% of the cyclists had osteopenia or osteoporosis (61% of non-athletes). Of the 19 cyclists 6 became osteoporotic during the 7 years.

Campion F, Nevill AM, Karlsson MK, Lounana J, Shabani M, Fardellone P, Medelli J. 2010. Bone status in professional cyclists. Int J Sports Med 31(7):511-5.

STUDY CONCLUSION: “Professional cycling appears to negatively affect BMD in young healthy and highly active males, the femoral neck being the most affected site (-18%) in spite of the elevated muscle contractions inherent to the activity.”

COMMENTS: Compared with amateurs, pro road cyclists probably spend less time walking, running, lifting weights or doing other things that encourage bone growth as they are highly focused on recovery and staying off of their legs after workouts.

Wilks DC, Gilliver SF, Rittweger J. 2009. Forearm and tibial bone measures of distance- and sprint-trained master cyclists. Med Sci Sports Exerc 41(3):566-73.

STUDY CONCLUSION: “Sprint cyclists and to a lesser extent distance cyclists had greater tibia and radius bone strength surrogates than the controls, with tibial bone measures being well preserved with age in all groups. This suggests that competition-based cycling and the associated training regime is beneficial in preserving average or above-average bone strength surrogates into old age in men.”

COMMENTS: This is the only study I’ve found which shows that competitive road cycling preserves bone mineral density in cyclists.

Smathers AM, Bemben MG, Bemben DA. 2009. Bone density comparisons in male competitive road cyclists and untrained controls. Med Sci Sports Exerc 41(2):290-6.

STUDY CONCLUSION: “Our findings indicated that male cyclists had lower spine BMD than controls, which was not associated with group differences in testosterone.”

COMMENTS: Despite a higher calcium intake by the road cyclists, 9% of the cyclists and 3% of non-athlete controls who were age-matched with the cyclists were classified as osteoporotic, whereas 25% and 10% of cyclists and controls, respectively, were osteopenic. I’ll come back to this calcium-intake oddity in the next post.

Medelli J, Lounana J, Menuet JJ, Shabani M, Cordero-MacIntyre Z. 2009. Is osteopenia a health risk in professional cyclists? J Clin Densitom 12(1):28-34.

STUDY CONCLUSION: “In conclusion, two-thirds of professional cyclists had abnormally low BMD values.”

COMMENTS: 23 professional male road cyclists aged 28.5 (+/- 3.9) years were tested for BMD of the lumbar spine (lower back), arm and leg. Climbers had the lowest arm BMD and time trialists the highest spine BMD. Most were at least osteopenic.

Barry DW, Kohrt WM. 2008. BMD decreases over the course of a year in competitive male cyclists. J Bone Miner Res 23(4):484-91.

STUDY CONCLUSION: “This study suggests that high intensity cycle training may adversely affect BMD. Excessive dermal calcium loss during exercise may be a contributing factor, but mechanisms remain to be elucidated.”

COMMENTS: 14 male road cyclists, 27-44 yr of age, were tested for BMD over the course of a year including bicycle training and racing. For one year some took in 1500mg of supplemental calcium citrate daily while others took in 250mg daily. BMD was found to decrease significantly in the hip and femur (thigh bone) of the subjects. There was no difference in BMD between the two groups regardless of how much calcium they consumed. (Again, more on this in a later post.) The authors believe the cause may be a loss of calcium in sweat. This seems doubtful given that runners also sweat heavily but don’t lose hip or femur BMD as cyclists do.

Nichols JF, Palmer JE, Levy SS. 2003. Low bone mineral density in highly trained male master cyclists. Osteoporos Int 14(8):644-9.

STUDY CONCLUSION: “These data indicate that master cyclists with a long history of training exclusively in cycling have low BMD compared to their age-matched peers. Although highly trained and physically fit, these athletes may be at high risk for developing osteoporosis with advancing age."

COMMENTS: Three groups of men were studied: 27 older road cyclists (51.2+/-5.3 years); 16 young adult road cyclists (31.7+/-3.5 years,); and 24 non-athletes matched by age (+/-2 years) and body weight (+/-2 kg) to the older cyclists. All of the cyclists had been training and racing for at least 10 years. Otherwise, they engaged in little or no weight-bearing exercise. The non-athletes were “normally active” (which I take t mean they did little or no exercise). BMD of the lumbar spine and hip was significantly lower in the master cyclists compared to both the non-athletes and the young adult cyclists. Among the older cyclists weight-bearing exercise performed during teen and young adult years did not appear to influence BMD by the time they were in their late 40s.

Warner SE, Shaw JM, Dalsky GP. 2002. Bone mineral density of competitive male mountain and road cyclists. Bone 30(1):281-6.

STUDY CONCLUSION: “Higher BMD in the mountain cyclists suggests that mountain cycling may provide an osteogenic stimulus that is not inherent to road cycling.”

COMMENTS: Three groups were studied: 16 competitive mountain bikers, 14 competitive road cyclists and 15 recreationally active men (control group). BMD was significantly higher at all sites in the mountain cyclists compared with the road cyclists and controls. Mountain biking may not have as deleterious an effect on BMD as road cycling. The study also suggests that it may be more beneficial than being “recreationally active.” This may be due to the need to dismount and run with, and perhaps even carry, the bike over challenging sections on the course.

Stewart AD, Hannan J. 2000. Total and regional bone density in male runners, cyclists, and controls. Med Sci Sports Exerc 32(8):1373-7.

STUDY CONCLUSION: “Running is associated with increased bone density, particularly in the leg, whereas cycling is associated with a mild decrease in bone density in the spine. In athletes who do both, running exerts a stronger influence than cycling.”

COMMENTS: Male athletes who were runners (N = 12), road cyclists (N = 14), or both (N = 13) were compared with non-exercising, age-matched controls (N = 23) for BMD. All athletic subjects had competed for a minimum of 3 years and trained for a minimum of 4 hours per week. Runners did no cycling and cyclists did no running training. Compared with the controls, runners had a greater total body and leg BMD, cyclists had reduced spine BMD, and athletes of the "both" group had greater total body and arm BMD. Essentially, running, even if mixed with cycling as with triathletes, seems to maintain or even improve BMD.

In a coming post I’ll get into what the research seems to be saying about how to maintain BMD. I think this is especially important for road cyclists. Hopefully, time will permit me to get at this later in the week. We’ll see.

Midsole Bike Cleat & Running Performance

I’m still often asked if I have the cleats on my cycling shoes in the midsole position as I first reported here in January of 2007 and then followed up with more posts in December, 2007, and December, 2009. (There have also been a number of comments posted by readers which you can also find by simply doing a search—right side of home page—for “cleat.”) The answer to the question is “yes,” I still use a midsole cleat position. I have my shoes custom made by D2 Shoe to accommodate this position.

I’ve suspected for many years now that the greatest benefit of midsole cleats may actually come on the run following the bike leg in a triathlon. The reason for this line of thinking is that a midsole cleat requires less work by the calf muscles to pedal the bike thus allowing these primary mover muscles for running to be fresher when the run begins in a multisport race. Now there’s new research that supports this.

Carl Paton at the Eastern Institute of Technology in Hawkes Bay, New Zealand recently sent me the abstract for his latest study which addresses this matter (Paton, C.D., T. Jardine. 2011. The effects of cycling cleat position on subsequent running performance during a simulated duathlon.) The paper is unpublished as of this writing but Carl mentioned that it would be submitted to a journal soon

In this study Paton and Jardine had 12 well-trained, competitive triathletes do 2 bike-run experiments. The bike portion was 30 minutes to be done at about 85% of VO2 max (roughly anaerobic threshold for well-trained athletes). They then immediately started a treadmill run of 5.5km at a maximal, self-paced effort. For one of the experiments they used a normal, traditional cleat placement on the cycling shoe—under the ball of the foot. For the other experimental condition they wore a shoe with a midsole cleat. The order of the experiments was randomized. (I don’t know this, but I suspect the subjects were unadapted to the midsole cleat position.)

Run times were significantly faster (2.2%) with the midsole cleat position as compared with the traditional position. Oxygen consumption was slightly but insignificantly higher in the runs following the midsole cleat experimental ride. Using more oxygen would be expected if they were running faster. There were no other significant differences or noticeable trends between metabolic variables during the cycling phase of the 2 experiments.

This is the first study I’ve seen that addressed this effect of midsole cleats on running performance. I’ll keep watching for more. If you know of any such studies please send them my way. Thanks.