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Vertical Ground Reaction Force
To create a larger vertical ground reaction force, you must ride on the hardest surface available.
Coefficient of Friction
The rear tire should have a greater coefficient of friction than the front tire. To accomplish this, the rear tire should have the following characteristics compared to the front tire:
(1) the rear tire should be made of softer materials than the front tire
(2) the rear tire should have a rougher surface than the front tire
(3) the rear tire should have lower air pressure than the front tire
To create a larger muscle force, three factors that influence the size of the muscle force must be considered.
(1) Muscle Size
-a muscle with a larger physiological cross-sectional area will create more muscle force
-increase via resistance training
(2) Muscle Length
-muscles stretched to 120% of their natural resting length generate the most muscle force
(3) Speed of the Muscle Contraction
-muscles that are concentrically contracted at slower speeds generate greater force than muscles that are concentrically contracted at faster speeds
Muscles Involved in Cycling
ANKLE PLANTAR FLEXION
- Fibularis Brevis/Longus
- Tibialis Posterior
- Fibularis Tertius
- Tibialis Anterior
- Gluteus Maximus
- Rectus Femoris
- Vastus Lateralis/Intermedius/Medialis
- Biceps Femoris
- Adductor Magnus
- Gluteus Maximus/Medialis/Minimus
- Biceps Femoris
- Adductor Brevis/Longus/Magnus
- Gluteus Medialis/Minimus
- Psoas Major
- Rectus Femoris
The distance from the joint's axis of rotation to the line of pull of the muscle force.
To increase the moment arm distance, you would need to move the line of pull of the muscle force further away from the joint's axis of rotation.
One method for moving the line of pull of the muscle force would be to change the locations of the origin and insertion points for the muscle. It would be unethical to perform this type of surgery.
The only way we can change the moment arm distance is by changing the angle of the joint. When the long axes of the two bones connected at a joint are aligned long axis to long axis (straight line), the moment arm distance is the smallest.
SHORT-TERM for body component mass
(1) wear the lightest clothing possible
(2) wear the lightest shoes possible
SHORT-TERM for bicycle mass
(1) use a bicycle made of lightweight materials (e.g., carbon fiber or aluminum)
(2) use light weight wheels
(3) carry as little equipment as necessary
LONG-TERM for body component mass
(1) lose fat mass
Radius of Resistance
The distance from the joint's axis of rotation to the center of mass of the body component.
Individuals with shorter bones will have shorter radii of resistance. There is nothing we can do to decrease bone length.
We can change the radius of resistance by changing the angles of the joints within the body component being rotated. We can decrease the radius of resistance by rotating the body component closer to the joint axis of rotation.
Application Time of Each Joint Torque
Two execution phases must be performed at each joint:
AT THE ANKLE:
-during the execution phase, there should be concentric ankle plantar flexion joint torque during the push down
-during the execution phase, there should be concentric ankle dorsiflexion joint torque during the pull up
AT THE KNEE:
-during the execution phase, there should be concentric knee extension joint torque during the push down
-during the execution phase, there should be concentric knee flexion joint torque during the pull up
AT THE HIP:
-during the execution phase, there should be concentric hip extension joint torque during the push down
-during the execution phase, there should be concentric hip flexion extension joint torque during the pull up
Radius of Rotation
The distance from the joint's axis of rotation to the point of interest on the body component.
Individuals with longer bones will have longer radii of resistance. There is nothing we can do to increase bone length.
We can change the radius of rotation by changing the angles of the joints within the body component being rotated. Any change in a joint angle that rotates a portion of the body component farther from the axis of rotation will lengthen the radius of rotation.
During road cycling, the fluid you are moving through is air.
There are three atmospheric conditions that would reduce fluid density:
(1) higher altitude
(2) lower humidity
(3) warmer temperatures
Coefficient of Drag
A measure of the surface friction between the air and the surfaces of the road cyclist and the bicycle as the road cyclist moves through the air.
The coefficient of drag may be reduced by making the surface of the road cyclist and the bicycle smoother.
For the road cyclist, this can be accomplished in 4 different ways:
(1) cycling clothes must be made of materials that are extremely smooth
(2) cycling clothes must be tight-fitting
(3) the surface of the cyclist's shoes should be smooth
(4) any uncovered areas of the body should have body hair removed
For the bicycle:
The surface of the bicycle should be clean. Any dirt on the bicycle would increase the roughness of the surface and the coefficient of drag.
Area of Drag
A measure of the area of turbulent air behind the road cyclist as the road cyclist moves through the air.
There are 4 primary mechanisms for reducing the area of turbulent air behind the road cyclist:
(1) make the area of the road cyclist that collides with the air smaller
-hands are in front of the cyclist on the handle bars aligned with the torso
-cyclist is leaning forward with the torso slightly flexed to align with the bike
(2) make the area of the bicycle and the wheels that collides with the air smaller
-the bicycle should be narrow
-the wheels oh the bike should be narrow
(3) change the characteristics of the road cyclist to create better aerodynamics
-cyclist should wear an aerodynamic helmet
-if traveling 20 mph or greater, the helmet should have a roughened surface
-if traveling 20 mph or greater, the road cyclist should wear clothes designed to be aerodynamic
(4) change the characteristics of the bicycle and the wheels to create a more aerodynamic bicycle
-if traveling 20 mph or greater, the rims of each wheel should have surfaces that have been roughened
-a solid wheel may be used to reduce the are of drag
-if traveling 20 mph or greater, the solid wheel should have a roughened surface
A measure of the speed and direction of the air that is colliding with your body.
There are 2 approaches to reducing relative velocity.
(1) road cycle on days when there is little or no wind
(2) use a movement technique called "drafting"
-following cyclist experiences a smaller drag force
-less energy expenditure (can lead to finishing race/ride with a short duration sprint around lead cyclist)
Vertical Ground Reaction Force
There are 2 methods for reducing the magnitude of the vertical ground reaction force on the slowing down side of the model.
(1) create a smaller body component mass
SHORT-TERM: wearing the lightest clothing and shoes possible
LONG-TERM: changing body composition/loss of fat mass
(2) create a smaller bicycle component mass by:
-using a bicycle made of light weight materials (e.g., carbon fiber or aluminum) and light weight wheels
-carry as little equipment as possible
Coefficient of Friction
Friction is created between the tires and the ground. Although there are 2 tires on a bicycle, only one of the tires is part of the mechanism that speeds the bicycle up, the rear tire.
The front tire should have the following characteristics compared to the rear tire:
(1) the front tire should be made of harder materials than the rear tire
(2) the front tires should have a smoother surface than the rear tire
(3) the front tires should have higher air pressure than the rear tire
Application Time of Each External Force
Decreasing the application time of each external force that is slowing the body down is a major mechanism for reducing the magnitude of the internal forces the body must absorb.
The application time of the friction force starts when the wheels start to roll forward. It ends when the wheels stop rolling forward. Thus, there is no way to reduce the application time of the friction force.
Similarly, the application time of the vertical ground cannot be reduced. As long as the wheels are on the ground, the ground reaction force will be applied to the wheels.
For the drag force, there is also nothing that can be done to reduce the application time. If the bicycle is moving, a drag force will oppose the motion and slow the body down.
Theoretically, increasing the mass would be an effective method to reduce how much you slow down. Unfortunately, a larger mass is more difficult to move quickly.
There is a mass concept box on the speeding up side of the model; and the interpretation for that box was that the mass must be small if we want to effectively speed the body up. These two interpretations conflict.
However, the logic should be easy to see. We need to get the body moving quickly each time we propel ourselves forward. This requires the mass be as small as we can make it. There is no way to simultaneously increase the mass so that we don't slow down as much.
If you are planning to ride for 15 miles, then only ride 15 miles. Do not tide 15.1, 15.5 or 16 miles. How is this accomplished?
(1) when the road or path is curved, ride close to the curve
(2) ride in a straight line from curve to curve