So everybody knows that riding uphill is hard and that you need a certain amount of fitness to do it. If you think about it, there really are no fat XC riders - and they are known for encountering prolonged and technical ascents. But what about riding downhill? For most of us (sane) people, it's the more enjoyable part of the ride, but is it strenuous as well? Do you need fitness to descend and does downhill riding help you get healthier and fitter? Very little research has been conducted on downhill riding, with no studies having looked at descents over steep and technically challenging terrain (such as what we encounter on the Shore). With this in mind, I set out to take a preliminary look at the physical demands of uphill and downhill riding on a typical Mt. Fromme trail route, with the goal of defining just how hard riding downhill can be.
The Ride
Eleven intrepid souls were rounded up, weighed and measured, issued questionnaires, and set up to meet at the water towers of Fromme on March 29th and 30th, 2006. In typical Fromme fashion, the rain was steady and cool, but the riders' spirits weren't dampened. The initial route of Seventh Secret, Leppard, Kirkford, Crinkum, Cedar, and Roadside Attraction had to be adjusted because of snow cover beyond the 6th switchback. So the riders were fitted with special heart rate monitors and sent up at their own pace to Leppard, from where they would begin the descent. Pre-ride grip strength was taken to compare to post-ride levels as an indicator of muscular fatigue.
The Results
The riders ascended to the entrance to Leppard trail in an average time of 29 minutes, geared up and took a breather, then descended the trail network in a mean time of 20 minutes. The group's average heart rate during the ascent was approximately 148 bpm, representing around 80% of their predicted maximum heart rate. This information was valuable because it gave us a baseline level of effort for the ascent which we could then compare to the heart rate response during the descent. Interestingly, the average descent heart rate for the group (156 bpm) was statistically higher than that of the ascent, and represented 84% of the group's predicted max heart rate. This occurred even though the riders were riding at their normal (non-race) pace! Previous research using XC riders (5) shows that heart rates don't decrease during descents, but this is the first study to find that the descent heart rates were actually higher than the ascent heart rates. Check out the graph below for the pattern of heart rate response for the ascent (dotted line) and descent (solid line).
The graph above shows the average ascending and descending heart rates of the rider groups.
Grip strength showed a similar decrease for both the left and right hands of the riders, and averaged a drop of 9.6% (approximately 5kg) per hand. This was to be expected due to the role of the forearms in steering and manipulating the bike, in addition to the use of the brakes.
Relevance
So what does it all mean? Well, at first glance it appears that descending is actually harder than ascending - at least that's what the heart rate data shows. There is a significant demand for energy metabolism during downhill riding which drives the heart rate response. The body has to deal with a lot of forces when traversing rough and technical terrain, including manipulating the bike over and around obstacles, shifting and balancing the bike and rider's own bodyweight, absorbing impacts and vibrations, and pedaling for short stretches. All of these movements require a substantial amount of muscle mass to be active - in fact, it is reasonable to assume that most of the major muscles of the body are active during technical descents. The more active muscle, the more demand put on the oxygen delivery systems of the body - hence the increase in heart rate.
Research with XC riders has shown that downhill riding over moderate terrain is associated with forces of 5 times the rider's bodyweight on each wheel hub (2). Some of these forces are dampened by suspension travel however the legs, arms and trunk still play a significant role in force absorption (6), and thus must produce muscular forces over prolonged durations. This is especially the case seeing as how most of us spend upwards of 80 to 90% of the descent out of the saddle (1).
Is it possible that you'll gain just as much fitness benefit from going down as going up? Photo ~ David Ferguson
There are a few non-exercise related factors that could have affected heart rate while riding the trail route, including psychological (adrenaline) influences (4) and altered heart rate response to upper body muscle action (3). Overall though, these results are promising in that descending is at least as hard as ascending at a moderate pace.
The handgrip info is also revealing in that a decrease of almost 10% in force occurred over the course of the ride. For those of you looking to improve your riding performance, a little bit of forearm endurance training may go a long way.
Future Directions
With the data gleaned from this study, I'm moving forward with a more comprehensive study that will look at the physical demands of Freeride biking in more detail. I'll be running the study in early-mid June, so if you feel like being a lab rat, let me know. Massive thanks to Dizzy Cycles for providing the participants with some awesome swag, NSMB for the support and letting me recruit through the forum, Sharon and Lee for providing endless support, and the great participants that made it all happen. See you all on the trails!
Cam Birtwell
Master's Student, School of Physical Education
University of Victoria
Freeride Mountain Biking Physiology Study
Mt. Fromme, March 2006
References
1. Bader, S. 2006. Personal Communication: Telephone interview, March 27, 2006.
2. DeLorenzo, D., & Hull, M. 1999. A hub dynamometer for measurement of wheel forces in off-road bicycling. Journal of Biomechanical Engineering, 121(1): 132-137.
3. Seals, D. 1989. Influence of muscle mass on sympathetic neural activation during isometric exercise. Journal of Applied Physiology, 67(5): 1801-1806.
4. Seifert, J., Leutkemeier, M., Spencer, M., Miller, D., & Burke, E. 1997. The effects of mountain bike suspension systems on energy expenditure, physical exertion, and time trial performance during mountain bicycling. International Journal of Sports Medicine, 18: 197-200.
5. Stapelfeldt, B, Schwirtz, A., Schumacher, Y., & Hillebrecht, M. 2004. Workload demands in mountain bike racing. International Journal of Sports Medicine, 25: 294-300.
6. Wang, E., & Hull, M. 1997. A dynamic system model of an off-road cyclist. Journal of Biomechanical Engineering, 119(3): 248-253.
Fonte: NSMB
Para quem nao percebe ingles passo a explicar. Isto é um estudo que basicamente diz que o Dh é mais exigente para o nosso coração do que o XC, o que ao inicio pode parecer um "disparate", cientificamente esta correcto. Basicamente, comprime-se todo o treino em 3, 4 minutos e no XC comprime-se tudo em 2 a 3 horas. Por ser a descer quem está de fora pensa sempre que não envolve quase esforço nenhum, mas se há coisa mais exigente é o downhill...Tanto envolve que por vezes em provas chega-se ao fim branco pois o DH precisa de um nível de concentração tal que é normal o cérebro "desligar" certas funções para dar prioridade à concentração e performance física, logo deixa algumas funções do organismo "off", o que leva a coisas tipo isso que acontece várias vezes de se ficar sem cor... Por isto alguém disser que para fazer DH não é preciso estar em forma nem ter resistência como o pessoal do xc que aguentam horas seguidas a pedalar (como muita gente diz), convide-vos para umas belas descidas a fundo numa pista minimamente exigente e ai vao ver
Abraço.
The Ride
Eleven intrepid souls were rounded up, weighed and measured, issued questionnaires, and set up to meet at the water towers of Fromme on March 29th and 30th, 2006. In typical Fromme fashion, the rain was steady and cool, but the riders' spirits weren't dampened. The initial route of Seventh Secret, Leppard, Kirkford, Crinkum, Cedar, and Roadside Attraction had to be adjusted because of snow cover beyond the 6th switchback. So the riders were fitted with special heart rate monitors and sent up at their own pace to Leppard, from where they would begin the descent. Pre-ride grip strength was taken to compare to post-ride levels as an indicator of muscular fatigue.
The Results
The riders ascended to the entrance to Leppard trail in an average time of 29 minutes, geared up and took a breather, then descended the trail network in a mean time of 20 minutes. The group's average heart rate during the ascent was approximately 148 bpm, representing around 80% of their predicted maximum heart rate. This information was valuable because it gave us a baseline level of effort for the ascent which we could then compare to the heart rate response during the descent. Interestingly, the average descent heart rate for the group (156 bpm) was statistically higher than that of the ascent, and represented 84% of the group's predicted max heart rate. This occurred even though the riders were riding at their normal (non-race) pace! Previous research using XC riders (5) shows that heart rates don't decrease during descents, but this is the first study to find that the descent heart rates were actually higher than the ascent heart rates. Check out the graph below for the pattern of heart rate response for the ascent (dotted line) and descent (solid line).
The graph above shows the average ascending and descending heart rates of the rider groups.
Grip strength showed a similar decrease for both the left and right hands of the riders, and averaged a drop of 9.6% (approximately 5kg) per hand. This was to be expected due to the role of the forearms in steering and manipulating the bike, in addition to the use of the brakes.
Relevance
So what does it all mean? Well, at first glance it appears that descending is actually harder than ascending - at least that's what the heart rate data shows. There is a significant demand for energy metabolism during downhill riding which drives the heart rate response. The body has to deal with a lot of forces when traversing rough and technical terrain, including manipulating the bike over and around obstacles, shifting and balancing the bike and rider's own bodyweight, absorbing impacts and vibrations, and pedaling for short stretches. All of these movements require a substantial amount of muscle mass to be active - in fact, it is reasonable to assume that most of the major muscles of the body are active during technical descents. The more active muscle, the more demand put on the oxygen delivery systems of the body - hence the increase in heart rate.
Research with XC riders has shown that downhill riding over moderate terrain is associated with forces of 5 times the rider's bodyweight on each wheel hub (2). Some of these forces are dampened by suspension travel however the legs, arms and trunk still play a significant role in force absorption (6), and thus must produce muscular forces over prolonged durations. This is especially the case seeing as how most of us spend upwards of 80 to 90% of the descent out of the saddle (1).
Is it possible that you'll gain just as much fitness benefit from going down as going up? Photo ~ David Ferguson
There are a few non-exercise related factors that could have affected heart rate while riding the trail route, including psychological (adrenaline) influences (4) and altered heart rate response to upper body muscle action (3). Overall though, these results are promising in that descending is at least as hard as ascending at a moderate pace.
The handgrip info is also revealing in that a decrease of almost 10% in force occurred over the course of the ride. For those of you looking to improve your riding performance, a little bit of forearm endurance training may go a long way.
Future Directions
With the data gleaned from this study, I'm moving forward with a more comprehensive study that will look at the physical demands of Freeride biking in more detail. I'll be running the study in early-mid June, so if you feel like being a lab rat, let me know. Massive thanks to Dizzy Cycles for providing the participants with some awesome swag, NSMB for the support and letting me recruit through the forum, Sharon and Lee for providing endless support, and the great participants that made it all happen. See you all on the trails!
Cam Birtwell
Master's Student, School of Physical Education
University of Victoria
Freeride Mountain Biking Physiology Study
Mt. Fromme, March 2006
References
1. Bader, S. 2006. Personal Communication: Telephone interview, March 27, 2006.
2. DeLorenzo, D., & Hull, M. 1999. A hub dynamometer for measurement of wheel forces in off-road bicycling. Journal of Biomechanical Engineering, 121(1): 132-137.
3. Seals, D. 1989. Influence of muscle mass on sympathetic neural activation during isometric exercise. Journal of Applied Physiology, 67(5): 1801-1806.
4. Seifert, J., Leutkemeier, M., Spencer, M., Miller, D., & Burke, E. 1997. The effects of mountain bike suspension systems on energy expenditure, physical exertion, and time trial performance during mountain bicycling. International Journal of Sports Medicine, 18: 197-200.
5. Stapelfeldt, B, Schwirtz, A., Schumacher, Y., & Hillebrecht, M. 2004. Workload demands in mountain bike racing. International Journal of Sports Medicine, 25: 294-300.
6. Wang, E., & Hull, M. 1997. A dynamic system model of an off-road cyclist. Journal of Biomechanical Engineering, 119(3): 248-253.
Fonte: NSMB
Para quem nao percebe ingles passo a explicar. Isto é um estudo que basicamente diz que o Dh é mais exigente para o nosso coração do que o XC, o que ao inicio pode parecer um "disparate", cientificamente esta correcto. Basicamente, comprime-se todo o treino em 3, 4 minutos e no XC comprime-se tudo em 2 a 3 horas. Por ser a descer quem está de fora pensa sempre que não envolve quase esforço nenhum, mas se há coisa mais exigente é o downhill...Tanto envolve que por vezes em provas chega-se ao fim branco pois o DH precisa de um nível de concentração tal que é normal o cérebro "desligar" certas funções para dar prioridade à concentração e performance física, logo deixa algumas funções do organismo "off", o que leva a coisas tipo isso que acontece várias vezes de se ficar sem cor... Por isto alguém disser que para fazer DH não é preciso estar em forma nem ter resistência como o pessoal do xc que aguentam horas seguidas a pedalar (como muita gente diz), convide-vos para umas belas descidas a fundo numa pista minimamente exigente e ai vao ver
Abraço.