Abstract：
PURPOSE:This study investigated the changes in running mechanics and spring-mass behavior over a 24-h treadmill run (24TR). METHODS:Kinematics, kinetics, and spring-mass characteristics of the running step were assessed in 10 experienced ultralong-distance runners before, every 2 h, and after a 24TR using an instrumented treadmill dynamometer. These measurements were performed at 10 km·h, and mechanical parameters were sampled at 1000 Hz for 10 consecutive steps. Contact and aerial times were determined from ground reaction force (GRF) signals and used to compute step frequency. Maximal GRF, loading rate, downward displacement of the center of mass, and leg length change during the support phase were determined and used to compute both vertical and leg stiffness. RESULTS:Subjects' running pattern and spring-mass behavior significantly changed over the 24TR with a 4.9% higher step frequency on average (because of a significantly 4.5% shorter contact time), a lower maximal GRF (by 4.4% on average), a 13.0% lower leg length change during contact, and an increase in both leg and vertical stiffness (+9.9% and +8.6% on average, respectively). Most of these changes were significant from the early phase of the 24TR (fourth to sixth hour of running) and could be speculated as contributing to an overall limitation of the potentially harmful consequences of such a long-duration run on subjects' musculoskeletal system. CONCLUSIONS:During a 24TR, the changes in running mechanics and spring-mass behavior show a clear shift toward a higher oscillating frequency and stiffness, along with lower GRF and leg length change (hence a reduced overall eccentric load) during the support phase of running.
journal_name
Med Sci Sports Exercjournal_title
Medicine and science in sports and exerciseauthors
Morin JB,Samozino P,Millet GYdoi
10.1249/MSS.0b013e3181fec518subject
Has Abstractpub_date
2011-05-01 00:00:00pages
829-36issue
5eissn
0195-9131issn
1530-0315journal_volume
43pub_type
杂志文章abstract：:Hydrostatic weighing (HW) was performed at residual volume (RV) and total lung capacity without head submersion (TLCNS). Ninety-five males (25.6 +/- 4.9 yr) and 87 females (22.6 +/- 5.2 yr) were studied at two laboratory sites using identical protocols. Twenty males and 20 females were separated from the original grou...
journal_title：Medicine and science in sports and exercise
pub_type： 临床试验,杂志文章,随机对照试验
doi：10.1249/00005768-198802000-00010
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abstract：PURPOSE:The purpose of this study was to compare the modified Broström and Evans procedures for simulated lateral ankle instability in cadaveric lower extremities. METHODS:Six normal cadaveric ankles were loaded with inversion and internal rotation stress through the range of ankle flexion, and three-dimensional motio...
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journal_title：Medicine and science in sports and exercise
pub_type： 临床试验,杂志文章,随机对照试验
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journal_title：Medicine and science in sports and exercise
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更新日期：1992-07-01 00:00:00
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journal_title：Medicine and science in sports and exercise
pub_type： 临床试验,杂志文章
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journal_title：Medicine and science in sports and exercise
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更新日期：2018-04-01 00:00:00
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journal_title：Medicine and science in sports and exercise
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journal_title：Medicine and science in sports and exercise
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journal_title：Medicine and science in sports and exercise
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doi：
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pub_type： 临床试验,杂志文章
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journal_title：Medicine and science in sports and exercise
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journal_title：Medicine and science in sports and exercise
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journal_title：Medicine and science in sports and exercise
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journal_title：Medicine and science in sports and exercise
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doi：
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