ALLI Sports Racer X Online MX Sports GNCC Racing Racer Productions The Racing Paper Racer X Brand

The Exercise Intensity of MX and SX Racing

by Dr Steve Augustine, Orthopedic Surgeon

Advertisement

By Gay, D; Keen, J; Riel, R; Evans, M; Milek ,M; Furman, T; Casillas, E; Augustine, S (senior author)

University of Florida HSC - Jacksonville
and
Jacksonville Orthopedic Institute (www.joionline.net)

We all know Motocross is tough....

photo: Simon Cudby

Introduction
Competitive off-road motorcycle racing has gained significant popularity in the past several years. In the United States the AMA motocross and supercross Championships are the nation’s best attended motorsport on dirt (1). Both types of racing take technical skills as well as physical fitness. Motocross and supercross races are physically demanding events with the competitors spending significant amounts of time training specifically for these events. With the recent boom in popularity of the sports and the subsequent increase in sponsorship money available, many of the athletes are looking to gain further insight into training modalities that may increase there competitive ability. But despite its recent increase in popularity, very little research has been done examining the physiological characteristics of the professional riders.

Methods
Twenty-six professional off-road motorcyclists agreed to partake in this study and were consented using an IRB approved protocol. Data was then collected from these individuals at various events on the SX and MX series. During a Supercross race a heat qualifier is six laps, a semi qualifier is five laps, a last chance qualifier is four laps, and a main event race is twenty laps. The Motocross racers were monitored at Unadilla and at Broome-Tioga. All racers competed in two motos and each moto was thirty minutes plus 2 laps. Eight of the consented racers were monitored at each event. If a rider withdrew from a race, only the completed qualifying races or completed motos were analyzed. If a rider did not qualify for the main event at the Supercross events, the data obtained during the qualifying races was analyzed and included for the mean calculations.


And the pros know how tough Supercross is....

Heart rate data was collected from the racers during the racing periods using a Polar S-610 Heart Rate monitor (Lake Success, NY) with the heart rate being recorded every 5 seconds during the events. The heart rate data was then transferred to a computer using a Polar infrared transmission device. The data was analyzed using Polar Precision Performance Software.

For the Supercross races the data was used to determine the maximum heart rate (HRmax) and the average heart rate (HRavg) for each racer during the qualifying races and main event if the racer qualified. The mean HRmax and HRavg for each qualifying race and main event race was then determined for each Supercross venue. For the Motocross races the data was used to determine the HRmax and HRavg for each racer for the two motos. Again the mean HRmax and HRavg for each race were calculated. The maximum heart rate was determined after completion of the study. All races were reviewed for each racer. The maximum heart rate recorded for each racer during all of the events was then used as the maximum heart rate (final HRmax). The percentage of maximum heart rate (% of HRmax) during each race was determined using the formula: HR avg/final HRmax X 100.


The cardiovascular demands of MX ans SX are higher than have been reported for professional road cyclist during similar duration events and for professional mountain bikers during events on similar terrain.


A student t-test was used to compare the qualifying races to the main event in the Supercross races. It was also used to compare to cumulative motocross moto data to the data from all of the recorded Supercross main events. Statistical significance was set at p<.05.

Results

Supercross
In the Supercross group, we obtained more data for the qualifying races than for the main events because the racers must place well in these events to progress to the main event. Table 1 shows the number of racers for which data was obtained for each event. Racers that withdrew from a qualifier or main event prior to its completion were not included.

Table 1. Supercross Races (number of monitored racers in each event)

1st Round
Qualitiers
2nd Round
Qualitiers
3rd Round
Qualitiers
Main Event
Indianapolis 5 4 2 2
Orlando 3 2 0 2
Daytona 5 6 4 2
Houston 3 3 0 2
Vegas 6 5 2 2
Cumulative 22 20 8 10

Figure 1 shows a typical heart rate profile of a racer during a 1st round qualifier and figure 2 shows a heart rate profile during a main event. The mean average HR and mean maximum HR for all locations are reported in Table 2. The percentage of maximum HR of the competitors for the 1st round qualifiers, 2nd round qualifiers, last chance qualifiers, and the main event were 93%, 93%, 95%, and 94% respectively. The significant differences (p< 0.05) were between the 1st round qualifiers and the last chance qualifiers and between the 2nd round qualifiers and the last chance qualifiers. There was no significant difference between any of the qualifying races and the main event.

Figure 1: Heart Rate during a Supercross heat qualifier
Figure 2: Heart Rate during a Supercross main event


Table 2. HRavg and HRmax for all Supercross races

1st Round
Qualitiers
2nd Round
Qualitiers
3rd Round
Qualitiers
Main Event
All Locations HRavg HRmax HRavg HRmax HRavg HRmax HRavg HRmax

178 bpm
188 bpm
180 bpm
188 bpm
183 bpm
188 bpm
180 bpm
188 bpm

Motocross

Table 3 demonstrates the number of races for each event in which we obtained heart rate data. Racers that had to withdraw prior to completion of a moto were not included.

Table 3. Motocross Races (number of monitored racers in each event)

Moto 1 Moto 2 Total
Unadilla 4 2 6
Binghamton 2 1 3
Total 6 3 9

Figure 3 shows an example profile of the heart rate pattern during a motocross race. For moto 1 of motocross the HRavg and HRmax was 177 and 185 respectively. For moto 2 the HRavg was 177 and the HRmax was 183. In moto 1 the racers averaged 94% of their HRmax and 96% in moto 2. There was no significant difference between the first and second motos. When all of the motocross motos were compared to the supercross main events there was no statistically significant difference.


Figure 3: Heart Rate pattern seen during a motocross moto

 

 

 

 

 

 

 

 

 

Discussion
Very little scientific investigations of professional off-road motorcycle racers has been performed. This study was performed to gain some insight into the physical demands of this type of competition. There is often the misconception that the riders themselves do not have a large physiologic demand during the race because the motorcycle itself is doing most of the workload for locomotion. This study demonstrates that there is at least a significant demand on the cardiovascular system during these races.

Gobbi et al. (2) evaluated the physical characteristics of enduro, desert rally, and motocross racers. They found that motocross racers had a higher BMI and a higher maximum aerobic power when compared to controls. They also found that their grip strength and leg strength were higher when compared to controls. All motocross racers were stronger in their left non-dominate arm. This is assumed to be due to the frequent use of the clutch that is operated by the left hand. A small part of Gobbi et. al. examined the heart rates and blood lactate levels of a motocross event. They found that the heart rate ranged from 180-200 and is generally higher than 80% of the predicted heart rate maximum during the duration of the race. Blood lactate concentrations of the motocross racers were significantly higher than the enduro or dessert rally racers.

And now the rest of the world nows....

Photo: Simon Cudby

Our study performed a more thorough examination of the heart rate response to motocross racing and to our knowledge is the first study to examine the heart rate response of professional supercross racers. Our findings of the heart rate response are similar to Gobbi et al. We found that during a motocross race the competitors average heart rate was between 92-96% of their maximum. While examining supercross racer’s percent of HRmax we found that there was a significant increase from the first two rounds of qualifying and the last chance qualifier. This increase is most likely due to the fact that the race is shorter in duration, there is fatigue present because these racers have already competed in two rounds of qualifiers, and because of the intense competition since only two racers advance from this round. Our findings demonstrate that cardiovascular strain in professional motocross racing is very high and that exercise intensity of Supercross racers is comparable to that of athletes in other professional sports. Professional road cycling is a well studied example of an endurance sport that is known to be physiologically demanding. Padilla et al. (3) observed that world-class cyclists are capable to bear intensities of 85-89% of HRmax during short distances (<40k) and prologue time trials (<10k), 78-80% during long-distance (>40k) and uphill time trials.

Mountain biking is a sport that resembles off-road motorcycling in regards to the terrain traversed and the physical demands of the body. Impellizzeri et al. (4) and Stapelfeldt B et al. (5) investigated the exercise intensity of professional athletes in this sport. They found that much like supercross and motocross there was little variation in heart rate during the events and there was a significantly elevated heart rate. Impellizzeri found an average HR of 90% of HRmax and Stapelfeldt reported 91% of HRmax. These values are slightly lower than the values we found for supercross, 93-95%, and motocross, 94-96%.

Conclusion
This study demonstrates that supercross and motocross are physically demanding sports. The cardiovascular demands are higher than have been reported for professional road cyclist during similar duration events and for professional mountain bikers during events on similar terrain. These findings suggest that intense aerobic and anaerobic training specifically designed for these athletes may improve their competitive advantage.

That's it for now, until next time, good luck with your training and remember, if you have a question, log on to the Virtual Trainer Expert Forum and have your question answered by a panel of experts. In addition, be sure and check out the Racer X Virtual Trainer archive section. Your complete one-stop information zone for motocross fitness. VT Signature

Share on:

Discussion

  1. Gravatar
    Mark January 26, 2012 at 1:37 pm

    I think there was a Swedish study done in the 1970s that showed professional motocross was second only to Soccer as the most physically demanding sport. How do these newest results compare to the earlier study?

  2. Gravatar
    Racer X Virtual Trainer January 26, 2012 at 1:39 pm

    Not sure, Mark but that sounds like a great research project for you. Time to hit the library!

  3. Gravatar
    Kip Gillett January 26, 2012 at 2:08 pm

    I applaud the use of statistic to measure heart rate and to show how fit Motocross/Supercross riders are. However, this an incorrect method for this form of reseach. WIth the current design, you are missing many key components. It is lacking an discussion of variables(always more then one) that you are trying to control and how, an indepth lilerature review (even if there isn't any it should still explore other sports and the heart rate impact), and any limitations to your study. Nevermind reliability and validity. Also, its lacking the any impact of the study, such as what this means for training Motocross riders and what areas need to be address to help riders achieve growth.

    In my eyes, as person that has a Masters of Science degree and works with Statistics/Research everyday, you are lacking knowledge of statistical analysis and basic design. In the end it weakens your work. Your unintended design was actually corret, which is Action Research.This method is used to show progress, to explore areas, and to gain a knowledge of a topic or to guide your future focus. With this method (which this project really is), you do not need to account for variables and limitations. Its for growth and development of an area of interest, not a major and indepth study, which clearly this not.

    I am not trying to put you don't for your work, but this format takes away some of your creditabiltiy and knowledge you have on the science of training and excersie. Which I know from reading your work, is not the case. Statistical analysis is a great think, but it can also be used to sell or dazzle without providing an new knowledge on a topic or worse creating falsehoods. I think if I stated something about training that was flattly false, but put into a nice package, and put it on the net, you would be just a kin to correct me. Again, I applaud your work, knowledge, and willingness to explore all areas.

  4. Gravatar
    Racer X Virtual Trainer January 26, 2012 at 2:38 pm

    Kip - First off, really??? No wait, let me think about this....Okay, I'll stick with that.... really?

    FYI, there is a full report that exists but it is very boring and statistical and reads like, well a very boring and statistical report. I understand where you are coming from seeing as you do this sort of thing every single day of your life. I can appreciate that as I too have a Master Degree in Mechanical Engineering and worked in that field for 12 years. This report is not meant to be published in any peer reviewed scientific journal. It's merely here to show the motocross community some cool data. Nothing more, nothing less.

    I'm just messin' with you. Thanks for the comment...Okay, now get back to work!

  5. Gravatar
    Jordan Patik January 26, 2012 at 3:47 pm

    If anyone is interested in what is seen in peer reviewed scientific journals, here are a few fairly recent studies on motocross. The first two are full PDFs and the rest are abstracts.

    Physiological characteristics of top level off-road motorcyclist
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1725105/pdf/v039p00927.pdf

    Effect of offâ

  6. Gravatar
    Jordan Patik January 26, 2012 at 3:50 pm

    Effect of off-road competitive motocross race on plasma
    oxidative stress and damage marker
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658913/pdf/101.pdf

    Physiological, biochemical and functional changes induced by a simulated 30 min off-road competitive motocross heat.
    http://www.ncbi.nlm.nih.gov/pubmed/18974716

    Cardiorespiratory and neuromuscular responses to motocross riding
    http://www.ncbi.nlm.nih.gov/pubmed/18296976

    Cardiopulmonary loading in motocross riding
    http://www.ncbi.nlm.nih.gov/pubmed/17497401

  7. Gravatar
    Eddie Casillas January 26, 2012 at 4:11 pm

    Kip what is the bottom line here?
    Motocross and Supercross riders are the baddest MF's of any sport when it comes down to fitness needed to perform.
    You have to have strength, power, muscle endurance, aerobic and anaerobic conditioning, dexterity, coordination, short and long term memory and testicles the size of watermelons.
    If I was hoping to turn this in for my PhD yes I would probably polish it up a bit, but instead I turned it in for my MxD.

    Let me know when you want to get yours.

  8. Gravatar
    Racer X Virtual Trainer January 26, 2012 at 5:27 pm

    Eddie - You must be in a good mood today. I was expecting much more venom from you :))

    Jordan - Thanks for the links. Long time since you submitted an article. About time don't you think. That goes for you too Eddie!

  9. Gravatar
    Greg DiRenzo January 26, 2012 at 5:35 pm

    Tim-Can I add more to the comment Eddie made? As you know I have an opinion on this as well, but for the children's sake I will opt out of responding here. But I will say, great article!

  10. Gravatar
    Joe Ulevicius January 26, 2012 at 5:41 pm


    It's been a while, and this was enough to have me chime in myself:

    First off, If Tim just posted full transcripts of the research discussed on this site, I'm guessing VT would be a bore and not be anywhere as useful unless you happen to ride off road and work in academia.(I can tell you that's rare.)

    Anyone that's willing to get this kind of data has their work cut out for them. Just the fact that a third of the field can be eliminated by the end of the event makes things tricky. I'm right now racking my brain trying to figure out what a control would even look like for this..? Maybe a guy sitting on a dyno for 20 minutes? Podium vs LCQ? Riders' energy drink intake levels... (ok maybe not)

    As an excerpt it illustrates a point and is obviously not meant for peer review... This isn't the JAMA website.

    Back to the point, it is a case for more study and getting more data with a larger sample group. While it's not in the same vein, with the new concussion testing being done this could lead to another aspect of monitoring safety in the sport. Could some sort of monitoring have prevented Josh Lichtle's demise this summer? While this shows some great bragging rights, there could be some real benefits from deeper research.

    What interests me far more as a rider and health advocate is where it goes from here. But what catches my eye is what we ( or I ) don't know. Looking at the graphs, (even assuming the small dataset and averages) what catches my eye is what comes after and before the race. There's a similar HR pattern at about two minutes before and after. Notably a spike after the event and a dip just before. The graph for motocross is cut off but does the trend follow through there as well? What's going on there? (Podium energy drink spike?) I'm no scientist, but I'm thinking that's interesting at the very least even if it's a known quantity to those in the know.

    Eddie, any comment on those?

  11. Gravatar
    Wayne January 26, 2012 at 6:25 pm

    Great work for increasing the evidance base for the sport of mx/sx.However my concern with the study is the use of heart rate to determine exercise intensity. I have raced motocross at a high level in the past and have also done a significant amount of road cycling and mountain bike racing. Im always the first to tell people how intense mx/sx is, but using heart rate to determine intensity is not very reliable. Anxiety has a huge effect on HR, we see this is many situations such as singers or performers getting high HR readings, passengers in a race car doing nothing but bracing themselves (yes i know this take some oxygen consumption but not much). In cycling power output, blood lactate levels and oxygen consumption are generally more accurate indicators for exercise intensity than HR although HR is still used as a simple measure to record.

  12. Gravatar
    David January 26, 2012 at 7:04 pm

    Wonder what this study would look like for endurocross.

  13. Gravatar
    Racer X Virtual Trainer January 26, 2012 at 7:19 pm

    Good point Wayne. I wonder if any of the trainers out there have ever tried to do Lactate Threshold tests on the motorcycle. Seems like a pretty risky venture. Would be interesting though.

  14. Gravatar
    Rob Styron January 26, 2012 at 8:09 pm

    Wayne makes a great point. I have always been interested in blood lactate with relation to anaerobic threshold during races. We test AT at my facility, but it would sure be fun (if you are a geek like me) to test after a main and compare.

  15. Gravatar
    Eddie Casillas January 26, 2012 at 11:20 pm

    I agree lactate would be great. We had a hard enough time convincing theses guys to 1. Run an HR monitor 2. The guys who already run HR giving us the numbers. We approched a few about lactate and were politely told hell no (something about being afraid of needles).

    I had an opportunity to test out a new monitoring device at Colorado last year. Through the use of telemetry we could monitor a riders HR, respiration, skin temp and G's. I was hoping to get some traction with AMA and riders as I think this would be cool info for the fans to see on TV as they follow a rider around the track.

  16. Gravatar
    Joe Ulevicius January 27, 2012 at 6:11 am

    Eddie, is that device you saw in Colorado available to the public?

  17. Gravatar
    Chris January 27, 2012 at 6:46 am

    Regarding Kip's comment, I recently had an encounter with a stats guy. He came across the same as Kip. He also failed to understand that not everyone speaks his language. It was clear to me when I read this article that it was meant for the masses, not the professional stats guys.

  18. Gravatar
    Racer X Virtual Trainer January 27, 2012 at 11:59 am

    I think Kips comments were meant with good intentions. If you truly want to stand up and shout about scientific research backing up a claim, you had better have your shit together. While I certainly think Eddie, Dr. Augustine and the rest of the Doctors who did this study have their shit together, I don't think they were trying to "prove" anything. Its just some cool data that shows some pretty high heart rates from gate to checkers. As a numbers guy, I love this sort of stuff.

    I have had some of my riders wear HR monitors with the intention of showing them how, if they relax through certain sections, they can lower their HR. Theory did not match reality. All the testing I have done shows exactly what is being shown here. Once the gate drops, the HR is pinned and that's that!. Pretty interesting stuff if you think about it!

  19. Gravatar
    KG January 27, 2012 at 1:42 pm

    On the subject of (World Cup?) Soccer once 'outranking' Motocross and Supercross as the most physically demanding sport in the world, I would offer the following current day observations, without any statistical information whatsoever to back it up.

    In its defense, Soccer and the level of training and overall fitness of the players has probably increased some % since the studies done in the 1970's.

    Shoes have become more supportive, now allow better airflow to cool the feet and cleat positioning has been reconfigured for better traction. Uniforms are made of better quality materials too giving the players a slight advantage over the clothing of 35-40 years ago.

    While better hydration options are in place Gatorade in who knows how many flavors), the playing field remains constant in it's size, shape & configuration. The 'goal' is still the same height and width as it was back then. In Soccer, the size of ''balls'' needed to play the sport has remained constant too.

    Todays Motocross boots, helmets, eye, knee and neck protection have become as protective and safe as the sport is gnarly.

    A Motocross/Supercross track in the 1970's was a wholly different 'playing field' from the Motocross/Supercross tracks of 2011/2012.

    Unadilla and Red Bud are still on the (outdoor) schedule but the difficulty level of racing competitively at these and other venues has surpassed anything imaginable from the 1970's.

    The machines from 'way-back' with their limited suspensions and quirkier 2-stroke characteristics were something of a challenge to ride at speed on any racing surface. Tires and heat were and remain another unstable factor for the riders and machines.

    Back then and still today, to be the best in the sport of Motocross/Supercross, a skill & fitness level, mental focus/strength when paired with the best prepared motorcycle despite the motorcycle's suspension and motor limitations -remains the unfair advantage.

    Todays riders possess a skill and fitness level that I would argue has increased 5-wise in the double digits and it is nothing short of extraordinary. The machines they ride are superbly engineered and built too.

    The skill/fitness level required of a Motocross/Supercross racer to compete and win, TODAY, in Motocross and Supercross has increased exponentially. Though scientific evaluation has not yet demonstrated these observations, they will no doubt soon bare out the findings that most of us already know to be fact: Motocross/Supercross is indeed, the most physically demanding sport in the world.

    Ultimately I have come to this single and solitary conclusion: While they are not directly on display during competition (as they are in the sport of soccer), I believe that in the modern era of Professional Motocross/Supercross, the size of ''BALLS'' needed to compete and Win are much bigger than were required in the 1970's of Soccer or Motocross/Supercross racers and will not soon be matched by a competitor of Soccer or any other sport for that matter.

    Thank you for this forum.

    Kevin Patrick Goulet

  20. Gravatar
    KG January 27, 2012 at 1:46 pm

    ERRORS:
    (Gatorade in who knows how many flavors) should have been written [Gatorade and others like Red-Bull, Monster, Muscle Milk, etc.]

    '5-wise' should have been written as 'percentage' wise.

  21. Gravatar
    Joel Younkins January 27, 2012 at 3:55 pm

    In Figures 1, 2, & 3, there is a quick drop in HR before each race. Is there any indication of what that is from?

  22. Gravatar
    Sean February 01, 2012 at 6:05 am

    I think the dip just before the gate drop could be time spent sitting at the start gate after doin a parade lap, getting focused. And the spike after the race may be anxiety from (depending on results ) doing tv interviews or explaining poor results to team managers.
    These are just my thoughts, not based on any scientific observation, merely pre and post race activities.

  23. Gravatar
    Joel Younkins February 01, 2012 at 3:45 pm

    Yeah could be a lot of things...just funny it was consistent throughout. I would have to go with you Sean and say it was the time spent relaxing on starting gate after parade lap.

  24. Gravatar
    Tomi Konttinen February 23, 2012 at 2:21 pm

    Physical strain of motocross riding is really interesting. I've done two published studies which Jordan Patik already linked.

    I think the most interesting thing is the influence of riding skills. Without the skills you are not fast enough to succeed. And in my opinion the speed doesn't need any special physical capabilility. But if you want to win races, and complete the whole season in top three, you have to be more than in really good shape.

    The main thing in physical strain, in my opinion is, that the most of the muscle work during riding is more or less isometric, wich differs really much of dynamic muscle work done for example during running, cycling, swimming etc. This influences the most for such high heart rates as measured during riding and also explaines why the measured VO2 max isn't the direct prediction of success. The more technical rider you are, the less energy you consume at the same "lap time" as your opponent. And at the same time, ofcourse, your heart rate, and lactate, are lower. But that gives more space for the more skilled rider to increase the speed.

    In my studies, also the blood lactate have been measured during riding. The race is ridden over the anaerobic thresold wheather the rider is less or more talented. The riding speed depends on skills and how long the rider can sustain the maximal speed, depends on physical capabilities concerning the strain that riding demands.

Leave a reply