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Gregor, R. J., Broker, J. P., Ryan, M. M. (1991). The biomechanics of cycling. Exercise And Sport Sciences Reviews, 19, 127-169.
Sather has PDF
NOTES
Much focus is placed on the pedals, but the rider interface with the handlebars and seat should not be ignored.
Kinematic features are mainly affected by cadence, rider-bicycle geometry, hip motion, and ankling pattern.
Reports on Bolourchi and Hull article of EMG. Peak handlebar force at 140 degrees of pedaling cycle. Average horizontal seat force significantly related to cadence.
p. 135
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Gregor, R. J. (2000). Biomechanics of Cycling. In Garrett, W. E. and Kirkendall, D. T. (Eds.) Exercise and Sport Science: Basic and Applied Science. Philadelphia: Lippincott Williams & Wilkins. 515-537.
Ch 35. p. 515-537
Exercise and Sport Science: Basic and Applied Science
Edited By William E. Garrett, Donald T. Kirkendall
Contributor William E. Garrett, Donald T. Kirkendall
Published by Lippincott Williams & Wilkins, Philadelphia, 2000
ISBN 0683034219, 9780683034219
Checked out from another library
Sather has hard copy
Limited information at
http://books.google.com/books?id=Cx22TcXodrwC&pg=PA522&lpg=PA522&dq=emg+...
NOTES
p. 522 Conclude that muscle activity increases as seat height decreases, especially in quadriceps and hamstring. Higher seat height allows for greater ease of pedaling.
Studies report anterior knee pain is most common type of knee pain.
Mellion suggests some injuries when seat is too high.
In the sagittal plane alone displacements, velocities, and accelerations of the thigh, leg, and foot appear to be most affected by cadence and bicycle setup (e.g. seat height, fore-aft position, crank length, and foot position on pedal).
Once the set-up is complete, lower-extremity kinematic patterns remain relatively constant.
Report on Rugg and Gregor (1987) that it appears that road riders choose between 106 and 109% of pubic symphysis height for saddle height.
Includes discussion of research demonstrating three-dimensional nature and movements on the frontal plane (p. 518-519)
Francis reported less frontal plane movement in elite cyclists using in-shoe orthotics. Trial-and-error adjustments in pedal cant, together with video feedback, reduced frontal plane movements which seemed to reduce knee pain.
Recommends continuously updating bicycle geometry.
McCoy research indicates the degree to which the knee deviates medially increases as seat height increases.
Ryan and Gregor (1992) EMG data displayed p. 523.
Major points of muscle activity: (a) coactivation of knee flexors and extensors appears during the first 90 degrees of pedal cycle, whereas hamstring and gastrocnemious muscles continue activation through the second quadrant and actually past bottom dead center, (b) Single-joint muscle activity is much more consistent across subjects than biarticular, (c) almost all muscles begin activity during muscle-stretch phase of the pedaling cycling. This begins before top dead center when muscles are typically being stretches and activity ends before the muscle has completed its shortening during the power phase.
Concludes from research on saddle height that muscle activity increases as seat height decreases, especially in quadriceps and hamstring.
Reports that symmetry in pedaling is rare and they see unequal loads on the right and left side quite often.
Good diagrams on vector forces p. 527
Browning (1991 unpublished masters thesis) examined the index of effectiveness with elite triathletes in aerodynamic versus advanced-aerodynamic position and found no change in force effectiveness. Effective force pattern just rotated forward, or clockwise. Browning also used range of pedal systems in his study.
Good discussion of pedal float and internal/external moments throughout the cycle p. 530. Pedals with float reduce resistive lateral forces that may cause injury. Concluded based on literature that regardless of pedal design, energy imparted to the bike is not compromised.
Concludes from research that muscle moments at the hip, knee and ankle have fairly repeatable patterns despite variations in load conditions, subject population, and bike setup.
Browning and colleagues (1988) reported ankle moment increased in peak magnitude as seat height decreased from 108% to 96% of pubic symphysis height.
Broker (1991 unpublished doctoral dissertation) studied the management of mechanical energy and load-sharing among hip, knee, and ankle joints using 12 elite cyclists at 200, 250, 300 watt workloads and 90, 100, and 110 RPM. Ericson and colleagues and Van Ingen Schenau estimate that greater than 80% of energy generated at the lower extremity joints can be delivered to the pedals. This is higher than running and walking. One model tested showed that the appropriate transfer of energy across two-joint muscles and limited the energy dissipated to nontransferable sources to less than 6 joules per limb during cycling. The regions of the pedaling cycle where energy transfers are possible are: (a) energy absorbed at the knee during the second quadrant (90-180 degrees) can potentially be transferred to the ankle by the active gastrocnemious and to the hip by the active hamstring and (b) Energy absorbed at the ankle and hip during the third quadrant can be potentially transferred to the knee by the active gastrocnemious and active hamstring muscles, respectively.
Reports it is now generally considered that single-joint muscles produce energy and biarticular muscles can transfer, or distribute, energy from one joint to another.
