Should Cyclists Be Concerned About Their Bone Density?

The low impact nature of cycling is one of its greatest attributes.  Cycling offers fitness and competition while nearly eliminating the impact found in other high intensity sports. If you’re nursing aches and pains from the glory days, cycling can be a refuge.  While less impact might be good for joints, it can be bad for bones [1] .

It makes sense that pro cyclists putting up 30 hour weeks are at risk for bone mineral density (BMD) loss [2], but what about those of us doing 6-10 hour weeks? How concerned should we be about bone density?

Making Comparison’s

In a recent study, researchers set out to compare the BMD of “recreational” and “trained” cyclists [3]. Cyclists averaged 39 years old (ages ranged from 21-54) and were split into groups based on weekly training volume. The recreational group trained on average 6 hrs/week and the trained group 11 hrs/week.

Researchers found lower whole body, lower lumbar, right hip, and left hip BMD in the trained group when compared to the recreational group.

In addition, 63% of trained and 44% of recreational cyclists were identified as osteopenic (lower than normal BMD).  Perhaps most surprisingly, 16% of the trained were osteoporotic [3]. In short, BMD loss was a problem for both recreational and trained cyclists riding in the 5-13 hrs/week range.

While a single study isn’t cause for panic, the larger context of BMD loss in endurance sports is cause for concern [1]. At the very least, masters aged cyclists should take a closer look at strategies to offset BMD loss [4] while young bucks would be wise to start thinking ahead.  So what is the best strategy to offset BMD loss?

Force and Impact

Strength training is certainly one option for offsetting BMD loss [4], but this article will focus on adding what cycling subtracts from the exercise equation: impact.

In a 2014 study, researchers set out to better understand the type of activity most effective for preventing bone loss in adolescents [5]. Using accelerometers, they measured the vertical impact of physical activity and the corresponding relationship to hip BMD.

Researchers found vertical impacts over 4g “largely accounted for the relationship between habitual levels of physical activity and BMD in adolescents” [5]. In other words, those hitting the 4g threshold during physical activity had healthier bones.  High impact, not just impact, was vital to BMD.

Specifics

So how does the 4g impact threshold translate to specific exercise recommendations?  In calibrating accelerometers for their study, researchers found that running speeds over a 9:40 m/mile generated greater than 4.2g while jumping from a 15” high platform generated impact above 5g [6].

Perfect, now we’re on to something. No equipment, no gym membership, and several simple exercises that may improve your longevity and durability as a cyclist.

Practical Implications

While the aforementioned study demonstrates that running hard can get you over the 4g threshold, I think plyometrics make more sense.

Plyometrics generate more impact than running and are simple to execute in your living room or garage. Here’s a basic workout to illustrate how you might incorporate plyometrics into your training. I call this workout the Bone Protector Ultra Max 3000.

The purpose of this workout is to add functional upper body strength while generating enough impact to potentially protect against BMD loss.  Knock it out in 15 minutes.  No gym membership or fancy equipment needed.

One major caveat:  If you have any joint pain or discomfort from these exercises, stop immediately.  Adding impact to your training must be measured against previous injuries or ailments.

Bone Protector Ultra Max 3000

Focus on impeccable/obsessive compulsive form for each exercise. Rest for 30s between each set.

3 X 10 Forward lunges, alternating each leg
3 X 15 Kneeling push-ups, progressing to full, then elevated as strength improves
3 X 30s Planks, progressing with more time as strength improves
3 X 10 Drop jumps from 15″ platform rebounding immediately into jump
3 X 10 Side jumps over center line or taller object as strength improves

Summary

1. Cyclists and other endurance athletes are at risk for bone mineral density loss (BMD). BMD loss isn’t just for fancy pros [2].  Cyclists training at moderate volumes are still at risk [1, 3-4].
2. Strength training can be an effective strategy to offset BMD loss [4]. Two other viable solutions are running hard and plyometrics [5, 6].
3. Plyometrics are an efficient strategy for generating enough impact to stimulate bone growth [5, 6].
4. If you ride a lot, are a masters cyclist, or have concerns about bone health, incorporating impact into your training might make you a more durable and healthy cyclist.
5. If impact is new to your training, be extremely careful and conservative as you add it to your routine.

References

1. Scofield, K.L. and S. Hecht, Bone Health in Endurance Athletes: Runners, Cyclists, and Swimmers. Current Sports Medicine Reports, 2012. 11(6): p. 328-334.
2. Medelli, J., et al., Is osteopenia a health risk in professional cyclists? J Clin Densitom, 2009. 12(1): p. 28-34.
3. Mojock, C.D., et al., Comparisons of Bone Mineral Density Between Recreational and Trained Male Road Cyclists. Clin J Sport Med, 2015.
4. Nichols, J.F. and M.J. Rauh, Longitudinal Changes in Bone Mineral Density in Male Master Cyclists and Nonathletes. The Journal of Strength & Conditioning Research, 2011. 25(3): p. 727-734.
5. Tobias, J.H., et al., Physical Activity and Bone: May the Force be with You. Front Endocrinol (Lausanne), 2014. 5: p. 20.
6. Deere, K., et al., Habitual Levels of High, But Not Moderate or Low, Impact Activity Are Positively Related to Hip BMD and Geometry: Results From a Population-Based Study of Adolescents. Journal of Bone and Mineral Research, 2012. 27(9): p. 1887-1895.