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Effects of a Comprehensive Exercise Training Regimen and KMgCit on Bone Elasticity as an Indicator of Bone Quality after 5 Weeks of Bedrest
Author(s) -
Krainski Felix,
Hastings Jeff,
Pacini Eric,
Richer Edmond,
Snell Peter,
Palmer Dean,
Zerwekh Joseph,
Antich Pietro,
Levine Benjamin D.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.752.5
Subject(s) - medicine , calcaneus , physical therapy , surgery
We investigated the effects of a multi‐load exercise program and KMgCit supplementation on the preservation of bone quality following 5 weeks of bedrest as measured by ultrasound critical‐angle reflectometry (UCR). The bone elasticity of 35 subjects (26 M, 9 F, 35 ± 10 yrs) was studied before and after bedrest. The subjects were divided into 4 groups: sedentary with no drug (n=12); sedentary with KMgCit (n=11); exercise (n=11); and exercise with KMgCit (n=4). The exercise group underwent intense multi‐joint rowing ergometry (30–45 min/d, 6 d/wk) and resistive strength training (2 d/wk). Subjects receiving the study drug were given 42:21:63 mEq KMgCit a day. Bone elasticity, a correlate of bone strength, was assessed by UCR on the tibia and calcaneus at multiple angles. In the sedentary group, prolonged bedrest resulted in a small decrease in bone elasticity, most notable in the more responsive trabecular bone (2.5%, 2779±140, 2709±92 m/s, p=0.06). KMgCit increased trabecular elasticity (4.2%, 2705±125, 2814±140 m/s, p<0.05), while exercise showed a similar trend (3.5%, 2701±121, 2798 ±100 m/s, p=0.08). Treatment with both exercise and KMgCit demonstrated a 1.9% increase, but included only 4 subjects. These findings suggest that KMgCit and exercise training are effective countermeasures against trabecular bone quality loss during prolonged periods in microgravity. Supported by NSBRI.