Real Time Monitoring
The Wattbike Performance Computer allows the tracking of the measured signals in real time (REAL-TIME monitoring) which offers the user and coach invaluable visual feedback that can be used to instantly correct technique. All the data is memorised during the monitoring and after the training this can be saved in a file for later analysis. Four graph modes are available:
Signal Mode
The Signal View displayed with different magnifications on the Wattbike Expert Software
The Signal Mode allows tracking of the signal curves in real-time. Specific signals can be switched On or Off, filtered, changed amplitude or change colour.
Analysis Modules Graph Mode
Two displays from the Analysis Modules Graph Mode
This mode allows the tracking of the calculated parameters (Power, Force, Work, Circumferential Pedal Velocity, Left Leg Percentage, Right Leg Percentage) in real-time. The data can be presented in "Line" or "Bar" mode. On the right hand side of the screen is a table with the templates (a prepared list of calculated parameters that can be shown). It is possible to add new, delete or edit existing templates. Every calculated parameter can be predefined with zones, and colours for every zone, representing the quality of that parameter. The resulting bars are drawn in their respective colour.
Polar Mode
The Polar View displayed in the Expert Software
In the Polar Mode, the signals are drawn in a radar or “polar” presentation. The Polar force curve on a Wattbike shows the peak force profile of the left and right leg downstroke:
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the left hand side is the left leg downstroke starting at the top of the graph (12 o’clock position) and finishing at the bottom of the graph (6 o’clock position)
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the right hand side is the right leg downstroke starting at the bottom of the graph (6 o’clock position) and finishing at the top of the graph (12 o’clock position)
The Polar View displayed in Recall Mode
The radius of each semi circle represents the amplitude of that signal. The more powerful the cycling the larger the radius, and the more constant the application of force throughout the pedal cycle the more balanced the signal for each leg.
The Polar Mode gives an insight into the force distribution between each leg. By switching the percentage parameters ON the percentage power output for each leg can be displayed at the bottom of the screen, monitoring the left-right leg symmetry. The Polar Mode also identifies the angle of force peak of each leg. If the cyclist knows the optimum angle of force peak they can immediately observe this parameter and adjust their cycling position on the bike accordingly.
Whilst the ideal force curve is yet to be determined a number of shapes show the effectiveness of applying force as the crank rotates to maintain momentum and minimise the ‘dead spots’ at the top and bottom of each pedal revolution (the force curve reducing to zero at the centre of the graph).
The shape of the force curve may be different for different types of cyclists and events i.e. sprint and endurance.
When out of the saddle the polar presentation shifts more towards a figure eight form, illustrating that most of the force application is applied pushing down, but when in the saddle and riding normally the cyclist can focus on creating the ideal shape by maintaining a constant force on both pedals throughout the downstroke of each leg. This offers the cyclist the opportunity to assess their pedal cycle technique and refine their technique to become more efficient.
The shape of each force curve usually has a diagonal lean with peak force achieved beyond the 90˚ (3 o’clock horizontal position). The angle of peak force will vary from individual to individual but should be at the same angle in each leg.
A single pedal revolution involves a downstroke-power phase and an upstroke-recovery phase with each leg. The downstroke phase delivers most of the force that generates forward momentum whilst the upstroke phase unloads the weight of the leg on the pedal and keeps the cranks rotating.
Pedalling is the movement of the legs in a circular motion to transfer muscular power to the pedals of a bike, in order to move the bike forward.
Pedalling effectively involves using the balls of the feet, keeping a constant speed and pedaling in a circular motion. A good general cadence [r/m] rate is 80-100 rpm although depending on the circumstances cadence can vary from 50 to 200 rpm.
A relaxed flowing style is more economical and maximizes energy use. In the early stages of learning to pedal it is best to develop efficient pedalling technique at a relatively high cadence with the focus on spinning.
However the Wattbike can be used for high cadence low wattage at one extreme and low cadence high wattage at the other.
On a bike, with the exception of gravity, the forces assisting speed are mainly produced by the force that is applied to the pedals. This is not simply a case of the size of the forces being applied, if a rider stands up briefly onto a horizontal crank a relatively large force will be produced, but will do little to propel the bike forward.
To propel a bike forward successfully a rider must continue to apply force as the crank rotates; the forward propulsion of the bike is dependent upon the force applied and the distance over which it is applied.
This is known as the work the rider does to the pedals. This tells us only how far the bike will move. If a rider pedals 10 times at a particular resistance (gear) the bike will travel the same distance per revolution whether they are turned at 50 r/m or 100 r/m but the rate at which they travel will be different.
Applying large forces to the cranks will not necessarily lead to forward propulsion of the bike. For example, if a downward force is applied to the cranks while the cranks are in a horizontal position (3 o’clock) this will act to turn the cranks and propel the bike forward.
If a downward force is applied when the cranks are at the vertical position (6 o’clock) the force cannot act to turn the cranks and will not propel the bike forward regardless of the size of the force.
In practice some of the force applied to the cranks does not act to turn the cranks. Most of the force is applied in a relatively small area of the crank cycle around the 3’ o’clock position when the crank is horizontal on the downstroke.
A rider may pull the pedal upward during the upstroke to unload the weight of the leg on the pedal and keep the crank rotating rather than creating a forward propulsive force.
Achieving optimal efficiency is not simply a case of applying all of the force at right angles to the cranks, as this does not take account of gravity or momentum.
