apnm-2014-0390R1
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Effect of a prior bout of preconditioning exercise on muscle damage from
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downhill walking
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Sumiaki Maeo1, 2, 3, Yusuke Ochi1, Masayoshi Yamamoto1,
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Hiroaki Kanehisa1, Kazunori Nosaka3
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Sports and Life Science, National Institute of Fitness and Sports in Kanoya Kanoya, Kagoshima, 891-2393, Japan
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Research Fellow of Japan Society for the Promotion of Science Kouji, Tokyo, 102-0088, Japan
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School of Exercise and Health Sciences, Centre for Exercise and Sports Science Research,
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Edith Cowan University
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Joondalup, Western Australia, WA 6027, Australia
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Corresponding author: Sumiaki Maeo
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Sports and Life Science, National Institute of Fitness and Sports in Kanoya
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1 Shiromizu, Kanoya, Kagoshima 891-2393, Japan
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E-mail:
[email protected]
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Telephone: +81-994-464932
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E-mail address:
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Yusuke Ochi:
[email protected], Masayoshi Yamamoto:
[email protected],
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Hiroaki Kanehisa:
[email protected], Kazunori Nosaka:
[email protected]
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ABSTRACT
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Purpose: This study investigated whether reduced-duration downhill walking (DW) would
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confer a protective effect against muscle damage induced by a subsequent bout of
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longer-duration DW performed 1 week or 4 weeks later. Methods: Healthy young adults
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were allocated to a control or one of the preconditioning exercise (PRE-1wk or PRE-4wk)
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groups (10 men and 4 women per group). PRE-1wk and PRE-4wk groups performed 20-min
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DW (-28% slope, 5 km/h, 10% body mass added to a backpack) 1 week and 4 weeks before
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40-min DW, respectively, and the control group performed 40-min DW only. Maximal
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voluntary contraction knee extension torque (MVC), plasma creatine kinase (CK) activity,
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and muscle soreness (100-mm visual analog scale) were measured before, immediately after,
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and 24, 48, and 72 h after DW, and the changes in these variables were compared among
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groups. Results: The control group showed symptoms of muscle damage (e.g. prolonged
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decrease in MVC: -14 ± 10% at 48 h post-DW) after 40-min DW. Changes in all variables
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after 40-min DW of PRE-1wk and PRE-4wk groups were 54-61% smaller (P
