A man is riding a bicycle whose paddle is at a distance of 20cm from the fulcrum .the man can exert the force of 4oN.what is the moment produced on the crank of bicycle when the paddle makes the angle of 1.(90) ° 2(45)° what is the line of action of force?
Answers
Explanation:
During submaximal cycling, the neuromuscular system has the freedom to select different intermuscular coordination strategies. From both a basic science and an applied perspective, it is important to understand how the central nervous system adjusts pedaling mechanics in response to changes in pedaling conditions.
Purpose
To determine the effect of changes in pedal speed (a marker of muscle shortening velocity) and crank length (a marker of muscle length) on pedaling mechanics during submaximal cycling.
Methods
Fifteen trained cyclists performed submaximal isokinetic cycling trials (90 rpm, 240 W) using pedal speeds of 1.41 to 1.61 m·s−1 and crank lengths of 150 to 190 mm. Joint powers were calculated using inverse dynamics.
Results
Increases in pedal speed and crank length caused large increases knee and hip angular excursions and velocities (P < 0.05), whereas ankle angular kinematics stayed relatively constant (P > 0.05). Joint moments and joint powers were less affected by changes in the independent variables, but some interesting effects and trends were observed. Most noteworthy, knee extension moments and powers tended to decrease, whereas hip extension power tended to increase with an increase in crank length.
Conclusions
The distribution of joint moments and powers is largely maintained across a range of pedaling conditions. The crank length induced differences in knee extension moments, and powers may represent a trade-off between the central nervous system’s attempts to simultaneously minimize muscle metabolic and mechanical stresses. These results increase our understanding of the neural and mechanical mechanisms underlying multi-joint task performance, and they have practical relevance to coaches, athletes, and clinicians.
Key Words: BIOMECHANICS, COORDINATION, ENDURANCE CYCLING, CRANK LENGTH
During cycling, power delivered to the pedals is produced by muscles that span the ankle, knee, and hip and by power produced in the upper body that is transferred across the hip joint (6,25). The investigation of the power contributions of the various muscle groups (i.e., joint action powers) to total mechanical power gives us invaluable insights into mechanical and physiological processes underlying exercise and cycling performance. For example, the analysis of joint action powers has increased our understanding of intermuscular coor efficiency

TABLE 1
Crank lengths, pedaling rates, and pedal speeds used in both experimental