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Five Jumps per Day Increase Bone Mass and Breaking Force in Rats
Author(s) -
Umemura Yoshihisa,
Ishiko Toshihiro,
Yamauchi Takeshi,
Kurono Masashi,
Mashiko Shoji
Publication year - 1997
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1359/jbmr.1997.12.9.1480
Subject(s) - jump , tibia , femur , bone mass , muscle hypertrophy , anatomy , body weight , jumping , zoology , medicine , biology , endocrinology , surgery , osteoporosis , physics , physiology , quantum mechanics
The effects of jump training on bone morphological and mechanical properties were investigated in immature bones of female Fischer 344 rats. Five‐week‐old rats were divided into control or five jump‐trained groups comprised of 5‐, 10‐, 20‐, 40‐, and 100‐jump groups, representing the number of jumps per day. The rats were jump‐trained 5 days/week for 8 weeks, and the height of jump was increased to 40 cm progressively. The femur and tibia in the 5‐jump group had significantly greater fat‐free dry weights per body weight and maximum loads at the fracture tests than those in the control group. The tibia in the 5‐jump group also had significantly larger cortical area at the cross‐sectional analysis. Although a slight tendency toward increase according to the number of jumps per day was observed, there were few differences in bone morphological and mechanical parameters among the 10‐, 20‐, and 40‐jump groups. The present results indicate that a large number of strains per day is not necessary for bone hypertrophy to develop in rats.