Exercise When Young Provides Lifelong Benefits to Bone Structure and Strength

• DOI: 10.1359/jbmr.061107
• Publication Date: 2006-11-27T19:23:27Z
• Authors: Stuart J Warden; Robyn K Fuchs; Alesha B Castillo; Ian R Nelson; Charles H Turner
• Keywords: Bone structure; Bone remodeling; Physical exercise

Short-term exercise in growing rodents provided lifelong benefits to bone structure, strength, and fatigue resistance. Consequently, when young may reduce the risk for fractures later life, old adage of "use it or lose it" not be entirely applicable skeleton.The skeleton is most responsive exercise, but low-trauma predominantly occur adults. This disparity has raised question whether exercised-induced skeletal changes during growth persist into adulthood where they have antifracture benefits. study investigated brief results quantity, quality, mechanical properties.Right forearms 5-week-old Sprague-Dawley rats were exercised 3 days/week 7 weeks using forearm axial compression loading model. Left internal controls exercised. Bone quantity (mineral content areal density) structure (cortical area minimum second moment [I(MIN)]) assessed before after detraining (restriction home cage activity). Ulnas removed 92 (at 2 years age) quality (mineralization) properties (ultimate force life).Exercise induced consistent structural adaptation. The largest effect was on I(MIN), which 25.4% (95% CI, 15.6-35.3%) greater ulnas compared with nonexercised ulnas. differences did detraining, whereas all absolute difference between maintained. After had 23.7% 13.0-34.3%) ultimate force, indicating enhanced strength. However, also lower postyield displacement (-26.4%; 95% -43.6% -9.1%), increased brittleness. resulted from mineralization (0.56%; 0.12-1.00%), influence 10-fold ulnas.These data indicate that can potentially, fracture risk. They suggest individuals undergoing should encouraged perform impact exercise.