Ultra-trail Runners Research Articles

Aspects of respiratory muscle fatigue in a mountain ultramarathon race.

Ultramarathon running offers a unique possibility to investigate the mechanisms contributing to the limitation of endurance performance. Investigations of locomotor muscle fatigue show that central fatigue is a major contributor to the loss of strength in the lower limbs after an ultramarathon. In addition, respiratory muscle fatigue is known to limit exercise performance, but only limited data are available on changes in respiratory muscle function after ultramarathon running and it is not known whether the observed impairment is caused by peripheral and/or central fatigue. In 22 experienced ultra-trail runners, we assessed respiratory muscle strength, i.e., maximal voluntary inspiratory and expiratory pressures, mouth twitch pressure (n = 16), and voluntary activation (n = 16) using cervical magnetic stimulation, lung function, and maximal voluntary ventilation before and after a 110-km mountain ultramarathon with 5862 m of positive elevation gain. Both maximal voluntary inspiratory (-16% ± 13%) and expiratory pressures (-21% ± 14%) were significantly reduced after the race. Fatigue of inspiratory muscles likely resulted from substantial peripheral fatigue (reduction in mouth twitch pressure, -19% ± 15%; P < 0.01), as voluntary activation (-3% ± 6%, P = 0.09) only tended to be decreased, suggesting negligible or only mild levels of central fatigue. Forced vital capacity remained unchanged, whereas forced expiratory volume in 1 s, peak inspiratory and expiratory flow rates, and maximal voluntary ventilation were significantly reduced (P < 0.05). Ultraendurance running reduces respiratory muscle strength for inspiratory muscles shown to result from significant peripheral muscle fatigue with only little contribution of central fatigue. This is in contrast to findings in locomotor muscles. Whether this difference between muscle groups results from inherent neuromuscular differences, their specific pattern of loading or other reasons remain to be clarified.

Prevalence of injury in ultra trail running

PurposeThe purpose of the study was to find the rate of musculoskeletal injuries in ultra-trail runners, investigate the most sensitive anatomical areas, and discover associated predicting factors to aid in the effective prevention and rapid rehabilitation of trail running injuries.MethodsForty ultra trail runners responded to an epidemiological questionnaire.ResultsAt least one running injury was reported by 90% of the sample, with a total of 135 injuries were reported (111 overuse injuries, 24 appeared during competing). Lower back pain was the most common source of injury (42.5%). Running in the mountains (&lt;i&gt;p&lt;/i&gt; = 0.0004) and following a personalized training schedule (&lt;i&gt;p&lt;/i&gt; = 0.0995) were found to be protective factors. Runners involved in physical labor are associated with more injuries (&lt;i&gt;p&lt;/i&gt; = 0.058). Higher-level runners are associated with more injuries than lower-level cohorts (&lt;i&gt;p&lt;/i&gt; = 0.067), with symptoms most commonly arising in the lower back (&lt;i&gt;p&lt;/i&gt; = 0.091), hip joint (&lt;i&gt;p&lt;/i&gt; = 0.083), and the plantar surface of the foot (&lt;i&gt;p&lt;/i&gt; = 0.054). Experienced runners (&gt; 6 years) are at greater risk of developing injuries (&lt;i&gt;p&lt;/i&gt; = 0.001), especially in the lower back (&lt;i&gt;p&lt;/i&gt; = 0.012), tibia (&lt;i&gt;p&lt;/i&gt; = 0.049), and the plantar surface of the foot (&lt;i&gt;p&lt;/i&gt; = 0 .028). Double training sessions could cause hip joint injury (&lt;i&gt;p&lt;/i&gt; = 0.060).ConclusionsIn order to avoid injury, it is recommended to train mostly on mountain trails and have a training program designed by professionals.

Reply to Millet

Letters to the EditorReply to MilletG. Y. Millet, M. D. Hoffman, and J. B. MorinG. Y. MilletUniversité de Lyon, Saint-Etienne, France; and , M. D. HoffmanDepartment of Veterans Affairs, Northern California Health Care System, and University of California Davis Medical Center, Sacramento, California, and J. B. MorinUniversité de Lyon, Saint-Etienne, France; and Published Online:15 Aug 2012https://doi.org/10.1152/japplphysiol.00740.2012MoreSectionsPDF (27 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat SACRIFICING ECONOMY DOES NOT MEAN ENERGY COST ON A TREADMILL WILL BE HIGHto the editor: Determining factors of running performance are quite complex. G. P. Millet (1) suggests that ultramarathons are no different from shorter distance running events with regards to the importance of energy cost (Cr) and that the suggested specificities of ultramarathon running are due to the fact that “elite” athletes in this relatively new nonprofessional sport are not comparable with elite marathon runners. We fully agree that the number of runners at the elite level is lower in ultramarathons than in shorter distances, and we also agree that this may explain some of the published characteristics of ultramarathon runners.We contend that certain physiological and mechanical characteristics related to ultra-endurance running are specific to such extreme distances, independently of the “youth” of the sport and its localization mostly in the United States and Europe. For instance, it is true that athletes specializing in ultradistance running may have been less successful in the shorter distances where larger leg muscle mass may be a hindrance, and it is true that European/North American runners may have been more likely to run in ultramarathons than African runners who have thinner thighs/calves. Still, large thighs and calves are less detrimental at low speeds compared with high speeds based upon basic mechanics that internal work increases with speed and step frequency. In other words, velocity is much lower in ultramarathons and this has several mechanical and physiological consequences that were detailed in our original article. This is mostly due to the fact that leg and equipment mass is not as critical as is the importance of minimizing lower limb damage to improve endurance. In this context, it is correct that ultratrail runners should be light and should, in particular, have a very low percentage of body fat, but lower limb muscle mass may help to “support” long downhill sections requiring substantial eccentric work. This is not the case for mountain bike or road cycling uphill specialists.In our paper (2), we did not write that ultramarathon runners necessarily have a high Cr, as suggested by G. P. Millet. Instead, we argued that athletes may make adjustments that increase Cr during races. In other words, one may have a “normal” Cr when measured under laboratory conditions but not attempt to achieve such economy during competitions. Finally, although performance is only considered among elite athletes in his letter, our paper relates to performance of all runners, whatever their competitive level. We believe that considering the entire performance spectrum makes our arguments even more appropriate.In conclusion, it is apparent that there is a smaller number of elite-level participants in ultramarathons compared with shorter running events and this may explain some—but not all—results found in the literature. We proposed that certain measures to actually increase Cr under real race conditions may be more than offset through gains in endurance in ultramarathon running, and such a balance is essential for performance optimization, performance being viewed not only for elite athletes but among all runners.DISCLOSURESNo conflicts of interest, financial or otherwise, are declared by the authors.AUTHOR CONTRIBUTIONSAuthor contributions: G.Y.M. drafted manuscript; G.Y.M., M.D.H., and J.-B.M. edited and revised manuscript; G.Y.M., M.D.H., and J.-B.M. approved final version of manuscript.REFERENCES1. Millet GP. Economy is not sacrificed in ultramarathon runners. J Appl Physiol; doi:10.1152/japplphysiol.00642.2012.ISI | Google Scholar2. Millet GY , Hoffman MD , Morin JB. Viewpoint: Sacrificing economy to improve running performance—a reality in the ultramarathon? J Appl Physiol; doi:10.1152/japplphysiol.00016.2012.ISI | Google ScholarAUTHOR NOTESAddress for reprint requests and other correspondence: G. Y. Millet, Université de Lyon, F-42023, Saint-Etienne, France (e-mail: guillaume.[email protected]fr). Download PDF Previous Back to Top FiguresReferencesRelatedInformationRelated ArticlesEconomy is not sacrificed in ultramarathon runners 15 Aug 2012Journal of Applied Physiology More from this issue > Volume 113Issue 4August 2012Pages 687-687 https://doi.org/10.1152/japplphysiol.00740.2012History Published online 15 August 2012 Published in print 15 August 2012 Metrics