So lets get some serious discussion going about Powercranks. An independent crank system that makes the claim with 6-9 months of full immersion training that users will see a 40% improvement in power.
Powercranks (also briefly sold under the brand name Smart Cranks) are marketed as a training tool and have been the subject of several well performed studies published in quality journals like the European Journal of Applied Physiology and some lesser journals like Journal of Strength and Conditioning Research.
Many claims have been made about various riders using the cranks but none of their testing data has been made available to show if these claims have any merit. Some of the claims from riders have been backed with data but this data has in cases been shown to have been tampered with and in other cases the measurement is suspect due to a poorly calibrated power meter.
The rest of the support for a Independent Crank system comes from anecdotal evidence from riders claiming they felt a benefit from the system. Always hard to assess these claims as there is no control carrying out a similar workload using a normal crank to make a reasonable comparison. Also hard to rule out any third variable that could be causing a change in performance. One study led by Dixon and associates showed a marked improvement in power and VO2max but there was no control group to show if the same gains could be made by using a normal crank.
All of the published studies on independent cranking systems have found no significant change in cycling performance or cycling fitness after a period of 5-6 weeks. I will list all the current studies and their abstracts. Try Google Scholar to see if any of the studies are available in full text as often the abstract is heavy on the results section but light on the methods to determine if the research design was adequate. This obviously limits the utility of presentations made at conferences that were not published in academic journals and only the abstract is available.
It is clear from those with an understanding of exercise physiology and sports training science that the human body responds to the exercise stimulus instantly and adaptations to a period of training are rapid. The time period of 5-6 weeks is more than adequate to see any expected adaptations to a training stimulus and numerous training, dietary, recovery, psychological and biomechanical studies have seen significant changes in less than 2 weeks.
This runs counter to the claims of independent crank system manufacturers who state that the real adaptations occur after 6-9 months of full immersion training. Were these claims true and people who trained with a independent crank system who achieved a 40% improvement in power; we would expect to see these riders dominate the sport to an extent never seen before.
A 40% gain for an average cyclist who could produce 300 watts for a 40km TT would see them produce 420 watts. This equates to ~6mins over 40km. Of course what would be hard to separate is whether it is the independent crank system or the type of training performed that led to the improvement. This is why it is crucial to test any independent crank claim against a control group performing the same training using normal cranks.
There has been no evidence provided that any cyclist has even achieved this mythical 40% improvement in power even with independent cranks being available for the last 13 years. Various anecdotal reports have been made but the metrics used to determine a change in performance were not true performance measures.
One anecdotal claims was a 2 mile per hour increase in speed during a 2000 metre pursuit. A change in speed can be affected by many variables. Temperature, wind speed, wind direction, humidity, time of the season, competitive variables, training, equipment selection, bike position, flexibility, riding line on the track and many others. Even on an indoor track weather, even within a session, can have an influence in performances.
In 2008 an quasi-scientific study was attempted on the Slowtwitch.com website. Here is the report from one subject who measured his progress with a power meter while carrying out training with a independent crank system.
http://james-p-smith.blogspot.co.nz/2008_06_01_archive.html
While you read this I will upload the many independent crank system studies that have been performed.
Powercranks (also briefly sold under the brand name Smart Cranks) are marketed as a training tool and have been the subject of several well performed studies published in quality journals like the European Journal of Applied Physiology and some lesser journals like Journal of Strength and Conditioning Research.
Many claims have been made about various riders using the cranks but none of their testing data has been made available to show if these claims have any merit. Some of the claims from riders have been backed with data but this data has in cases been shown to have been tampered with and in other cases the measurement is suspect due to a poorly calibrated power meter.
The rest of the support for a Independent Crank system comes from anecdotal evidence from riders claiming they felt a benefit from the system. Always hard to assess these claims as there is no control carrying out a similar workload using a normal crank to make a reasonable comparison. Also hard to rule out any third variable that could be causing a change in performance. One study led by Dixon and associates showed a marked improvement in power and VO2max but there was no control group to show if the same gains could be made by using a normal crank.
All of the published studies on independent cranking systems have found no significant change in cycling performance or cycling fitness after a period of 5-6 weeks. I will list all the current studies and their abstracts. Try Google Scholar to see if any of the studies are available in full text as often the abstract is heavy on the results section but light on the methods to determine if the research design was adequate. This obviously limits the utility of presentations made at conferences that were not published in academic journals and only the abstract is available.
It is clear from those with an understanding of exercise physiology and sports training science that the human body responds to the exercise stimulus instantly and adaptations to a period of training are rapid. The time period of 5-6 weeks is more than adequate to see any expected adaptations to a training stimulus and numerous training, dietary, recovery, psychological and biomechanical studies have seen significant changes in less than 2 weeks.
This runs counter to the claims of independent crank system manufacturers who state that the real adaptations occur after 6-9 months of full immersion training. Were these claims true and people who trained with a independent crank system who achieved a 40% improvement in power; we would expect to see these riders dominate the sport to an extent never seen before.
A 40% gain for an average cyclist who could produce 300 watts for a 40km TT would see them produce 420 watts. This equates to ~6mins over 40km. Of course what would be hard to separate is whether it is the independent crank system or the type of training performed that led to the improvement. This is why it is crucial to test any independent crank claim against a control group performing the same training using normal cranks.
There has been no evidence provided that any cyclist has even achieved this mythical 40% improvement in power even with independent cranks being available for the last 13 years. Various anecdotal reports have been made but the metrics used to determine a change in performance were not true performance measures.
One anecdotal claims was a 2 mile per hour increase in speed during a 2000 metre pursuit. A change in speed can be affected by many variables. Temperature, wind speed, wind direction, humidity, time of the season, competitive variables, training, equipment selection, bike position, flexibility, riding line on the track and many others. Even on an indoor track weather, even within a session, can have an influence in performances.
In 2008 an quasi-scientific study was attempted on the Slowtwitch.com website. Here is the report from one subject who measured his progress with a power meter while carrying out training with a independent crank system.
http://james-p-smith.blogspot.co.nz/2008_06_01_archive.html
While you read this I will upload the many independent crank system studies that have been performed.