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A Perturbation Study of Lower Extremity Motion during Running

Wilbert Van Woensel and Peter R. Cavanagh

The present study explored kinematic adaptation in the lower extremity to running in shoes with 10° valgus and varus midsole perturbations. Rearfoot motion and knee flexion/extension data on nine subjects were collected using a Selspot II system during treadmill running in the two test shoes and in a neutral shoe condition. Maximum pronation was significantly altered by an amount approximately the same as the shoe perturbation, but there was no substantial adaptation in the amount of knee flexion. From the rearfoot patterns it was inferred that time to maximum pronation may be an unreliable variable to describe the pattern of rearfoot motion; the two-phase profile using rearfoot velocity may be more useful. It was concluded that certain subtle sagittal plane kinematic adaptations in timing and velocity patterns did occur at the knee in response to the shoe perturbations.

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Upper Extremity Function in Running. I: Center of Mass and Propulsion Considerations

Richard N. Hinrichs, Peter R. Cavanagh, and Keith R. Williams

Ten male recreational runners were filmed using three-dimensional cinematography while running on a treadmill at 3.8 m/s, 4.5 m/s, and 5.4 m/s. A 14-segment mathematical model was used to examine the influence of the arm swing on the three-dimensional motion of the body center of mass (CM), and on the vertical and horizontal propulsive impulses (“lift” and “drive”) on the body over the contact phase of the running cycle. The arms were found to reduce the horizontal excursions of the body CM both front to back and side to side, thus tending to make a runner's horizontal velocity more constant. The vertical range of motion of the body CM was increased by the action of the arms. The arms were found to make a small but important contribution to lift, roughly 5–10% of the total. This contribution increased with running speed. The arms were generally not found to contribute to drive, although considerable variation existed between subjects. Consistent with the CM results, the arms were found to reduce the changes in forward velocity of the runner rather than increasing them. It was concluded that there is no apparent advantage of the “classic” style of swinging the arms directly forward and backward over the style that most distance runners adopt of letting the arms cross over slightly in front. The crossover, in fact, helps reduce side-to-side excursions of the body CM mentioned above, hence promoting a more constant horizontal velocity.

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A Kinematic Profile of Skills in Professional Basketball Players

Irene S. McClay, John R. Robinson, Thomas P. Andriacchi, Edward C. Frederick, Ted Gross, Philip Martin, Gordon Valiant, Keith R. Williams, and Peter R. Cavanagh

Overuse injuries are common in basketball. To gain insight into their etiology and relationship to mechanics, researchers and clinicians need an understanding of the normal biomechanics of the sport. This study was undertaken with this goal in mind. Lower extremity joint kinematics and structural parameters were collected from 24 players from five professional basketball teams as they performed maneuvers typical of their sport. The results indicated that certain common moves such as the layup landing resulted in knee flexion velocities almost double those seen during the landing phase of running. Lateral movements such as cutting and shuffling placed the foot in extreme positions of supination. Both of these findings have implications for injuries common to basketball such as patellar tendinitis and ankle sprains. It is hoped that this information will initiate a database for normal lower extremity kinematics during basketball and lead to a greater understanding of the relationship of lower extremity movement patterns and injury.

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A Profile of Ground Reaction Forces in Professional Basketball

Irene S. McClay, John R. Robinson, Thomas P. Andriacchi, Edward C Frederick, Ted Gross, Philip Martin, Gordon Valiant, Keith R. Williams, and Peter R. Cavanagh

Basketball is a sport that involves multiple impacts with the ground through a variety of moves such as running Jumping, and cutting. Repetitive impacts have been associated with stress-related injuries in other sports such as running. The purpose of this investigation was to gain an understanding of the typical stresses the body experiences during common basketball moves. To this end, the ground reaction forces from 24 players from five professional basketball teams were studied. In addition, a game analysis was performed to determine the frequency of selected moves. These data indicated that certain common movements, such as jump landings and shuffling, resulted in absolute and relative forces much greater than many of those reported previously in studies of other sports. These movements were also identified in a companion paper as being associated with large angular excursions and velocities. Findings are discussed with respect to injury risks, and suggestions for future study are made.

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Impact of Biomechanics Research on Society

Ronald F. Zernicke, Grant C. Goulet, Peter R. Cavanagh, Benno M. Nigg, James A. Ashton-Miller, Heather A. McKay, and Ton van den Bogert

As a field, biomechanics comprises research from the molecular and cellular levels, to tissues, to organs, to organisms and their movements. In the past 50 years, the impact of biomechanics research on society has been amplified dramatically. Here, we provide five brief summaries of exemplar biomechanics results that have had substantial impact on health and our society, namely 1) spaceflight and microgravitational effects on musculoskeletal health; 2) impact forces, soft tissue vibrations, and skeletal muscle tuning affecting human locomotion; 3) childbirth mechanics, injuries, and pelvic floor dysfunction; 4) prescriptive physical activity in childhood to enhance skeletal growth and development to prevent osteoporotic fractures in adulthood and aging; and 5) creative innovations in technology that have transformed the visual arts and entertainment.

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An Approach to Biomechanical Profiling of Elite Distance Runners

Peter R. Cavanagh, Gary C. Andrew, Rodger Kram, Mary M. Rodgers, David J. Sanderson, and Ewald M. Hennig

A comprehensive biomechanical profile for the evaluation of elite distance runners is outlined. The profile includes the following sections: (a) structural assessment, (b) movement analysis, (c) plantar force and pressure, and (d) selected metabolic measurements. For each of these sections the methodology is described, examples of results from two elite distance runners evaluated are presented and, where appropriate, recommendations for performance improvement and/or injury prevention are made. The concluding discussion addresses a number of philosophical issues related to the biomechanical study of elite athletes and makes some' recommendations for farther development of programs of this nature.

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Evaluation of a Treadmill with Vibration Isolation and Stabilization (TVIS) for Use on the International Space Station

Jean L. McCrory, David R. Lemmon, H. Joseph Sommer, Brian Prout, Damon Smith, Deborah W. Korth, Javier Lucero, Michael Greenisen, Jim Moore, Inessa Kozlovskaya, Igor Pestov, Victor Stepansov, Yevgeny Miyakinchenko, and Peter R. Cavanagh

A treadmill with vibration isolation and stabilization designed for the International Space Station (ISS) was evaluated during Shuttle mission STS-81. Three crew members ran and walked on the device, which floats freely in zero gravity. For the majority of the more than 2 hours of locomotion studied, the treadmill showed peak to peak Linear and angular displacements of less than 2.5 cm and 2.5°, respectively. Vibration transmitted to the vehicle was within the microgravity allocation limits that are defined for the ISS. Refinements to the treadmill and harness system are discussed. This approach to treadmill design offers the possibility of generating 1G-like loads on the lower extremities while preserving the microgravity environment of the ISS for structural safety and vibration free experimental conditions.