Bozzini Clarisa, Viscor Ginés, Kristjánsson Juan C Ríos, Picasso Emilio, Champin Graciela, Alippi Rosa M, Bozzini Carlos E
Cátedra de Fisiología, Facultad de Odontología, Universidad de Buenos Aires, Argentina. E-mail:
Departament de Fisiología i Immunología, Universitat de Barcelona, España.
Biomed Mater Eng. 2017;28(4):431-441. doi: 10.3233/BME-171684.
Physical activity plays a tremendous role in determining bone mechanical behavior, which is superimposed to gravidity.
Compare the geometric and material responses of the rat femur to a high intensity treadmill running training of a relatively short duration, as assessed by 3-point mechanical test.
Mature male rats (180.0 ± 30 g) were assigned (7 rats/group) to no exercise (NE) or treadmill exercise (EX). After a preconditioning period, the running speed was set at 45 cm.seg-1 during 2 wks, frequency 5 d/wk, 2-hour sessions/day. Body weight and weight of the crural quadriceps were registered at euthanasia. The right femur was mechanically tested through 3-point bending. The left femur was ashed to estimate bone mineral content. Geometric and material bone properties were estimated directly or calculated by appropriate equations.
1) Final body weight was 14% reduced in EX rats, while the crural quadriceps was 47% increased. Yield and fracture loads, and structural stiffness were significantly higher in the EX rats, as were the apparent elastic modulus, the bone mineral content and the degree of mineralization. Geometric properties were not affected.
High intensity treadmill running training increases bone strength and stiffness by increasing material stiffness and mineralization, without affecting geometric bone parameters.
身体活动在决定骨骼力学行为方面起着巨大作用，而骨骼力学行为又受到重力的叠加影响。
通过三点力学测试，比较大鼠股骨对相对短时间高强度跑步机跑步训练的几何和材料反应。
将成熟雄性大鼠（180.0 ± 30 g）（每组7只大鼠）分为不运动组（NE）或跑步机运动组（EX）。经过预处理期后，在2周内将跑步速度设定为45 cm·s⁻¹，频率为每周5天，每天训练2小时。在安乐死时记录体重和股四头肌重量。通过三点弯曲对右侧股骨进行力学测试。将左侧股骨灰化以估计骨矿物质含量。直接估计或通过适当公式计算骨骼的几何和材料特性。
1）运动组大鼠的最终体重降低了14%，而股四头肌增加了47%。运动组大鼠的屈服载荷、骨折载荷和结构刚度显著更高，表观弹性模量、骨矿物质含量和矿化程度也是如此。几何特性未受影响。
高强度跑步机跑步训练通过增加材料刚度和矿化程度来提高骨骼强度和刚度，而不影响骨骼的几何参数。
