Originally posted by chuy
Just out of curiousity how accurate is this? I seem to have a max PI of around 90% however my average is around 20-30% ? Does this mean it's time to do One-Legged Pedaling Drills?
Originally posted by steve
What is pedaling index?
Originally posted by chuy
The s720i manual says the following: PI %, Pedalling Index*: Helps you to analyze how evenly the power is distributed. The smoother the pedalling motion, the closer the figure is to the ideal 100%. A pedalling index of 100% means that power is applied evenly throughout the whole pedal revolution.
Originally posted by ricstern
Distribution of pedal forces can only be measured with force instrumented pedals, which the polar (or any current power meter cannot do). In studies comparing better cyclists to less good ones, the better cyclists (elite) showed that higher power outputs (compared 40 km TT performance) were acheived by pressing down harder on the pedals and generated less force on the recovery phase of the pedal stroke.
Forget PI and left/right distributions.
Ric
Originally posted by HandyAndy
Ric does the computrainer not have that spinscan feature that measures individual power per leg?Ric is the computrainer a very useful training tool in your experience?
Originally posted by ricstern
Distribution of pedal forces can only be measured with force instrumented pedals, which the polar (or any current power meter cannot do). In studies comparing better cyclists to less good ones, the better cyclists (elite) showed that higher power outputs (compared 40 km TT performance) were acheived by pressing down harder on the pedals and generated less force on the recovery phase of the pedal stroke.
Forget PI and left/right distributions.
Ric
Originally posted by Feanor
I'm just taking a total layman's stab at this one, but doesn't the polar s720i power measurement unit measure the force imparted to the chain? and wouldn't that be at least a very strong indicator of force imparted to the pedals? Isn't it akin to grabbing a string and pulling on it and having someone determine how much force your hand motion was exhibiting by measuring the force at the end of the string?
The s720i also has the cadence sensor so at one time you could measure both the full cycle time in one revolution and "superimpose" that data on the profile of the forces imparted to the chain during one revolution. Although that would not be as _directly_ connected to pedaling force as measureing it from the pedals themselves, isn't it only one small step removed from the data?
I'm probably missing something, but though the data may in part be "muffled" by measuring cadence vs chain force to determine Pedalling Index, wouldn't it be like listening to a conversation thru a door? You don't hear it as well as if you are in the room, but you still get the completely accurate sense of what is being said...
Now I'm not sure how the computer would know left from right (unless it is somehow indexed at the start of motion, but by measuring cadence you just have to split revolutions into alternate "sides" you overlay the power profile data of the chain during each stroke and you have relative effeciency data, and relative side to side variation data...
Isn't that accurate enough? or are there issues with the Polar power measuring device? I reliaze that the polar system would be more accurate with measuring variations, and the pedal system would be more accurate at hitting the actual power "number"...
Have a good one!
Feanor
Originally posted by gregke
I am interested if anyone knows more about Ric's comment "higher power outputs (compared 40 km TT performance) were acheived... " Greg
Originally posted by 9606
Andy/Ric - in a nutshell, what does the general literature imply about improving, or training, a better pedal stroke? Are isolated leg exercises worthwhile? Should we pedal simply as it feels comfortable?
The polar meter analyzes 1 to 5 o'clock area of the pedaling stroke and compares it to the whole stroke. The reading that you get is really 1/3 (4 out of 12 hours on the proverbial clock) the total. if you were getting 30% with the polar that would mean 90% on the computrainer.chuy said:Just out of curiousity how accurate is this? I seem to have a max PI of around 90% however my average is around 20-30% ? Does this mean it's time to do One-Legged Pedaling Drills?
ric_stern/RST said:Distribution of pedal forces can only be measured with force instrumented pedals, which the polar (or any current power meter cannot do). In studies comparing better cyclists to less good ones, the better cyclists (elite) showed that higher power outputs (compared 40 km TT performance) were acheived by pressing down harder on the pedals and generated less force on the recovery phase of the pedal stroke.
Forget PI and left/right distributions.
Ric
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