Neuromuscular Research Centre, Department of Biology of Physical Activity, University of Jyväskylä, P. O. Box 35, 40014 Jyväskylä, Finland.
Eur J Appl Physiol. 2010 Jul;109(4):651-8. doi: 10.1007/s00421-010-1400-3. Epub 2010 Feb 27.
The osteogenicity of a given exercise may be estimated by calculating an osteogenic index (OI) consisting of magnitude and rate of strain. Volleyball involves repetitive jumping and requires high power output and thus may be expected to be beneficial to bone and performance. The purpose of the present study was to examine if habitual volleyball playing is reflected in OI. Ten elderly habitual volleyball players [age 69.9 (SD 4.4) years] and ten matched controls volunteered [age 69.7 (4.2) years] as subjects. Distal tibia (d), tibial mid-shaft (50) and femoral neck (FN) bone characteristics were measured using pQCT and DXA. To estimate skeletal rigidity, cross-sectional area (ToA(50)), and compressive (BSI(d)) and bending strength indices (SSImax(50)) were calculated. Maximal performance was assessed with eccentric ankle plantar flexion, isometric leg press and countermovement jump (CMJ). A fast Fourier transform (FFT) was calculated from the acceleration of the center of mass during the CMJ. Maximal acceleration (MAG) and mean magnitude frequency (MMF) were selected to represent the constituents of OI. OI was calculated as the sum of the products of magnitudes and corresponding frequencies. Volleyball players had 7% larger ToA(50) and 37% higher power in CMJ, 15% higher MAG and 36% higher OI (P <or= 0.047) than the matched controls. No difference was observed in leg press, plantar flexion or the MMF (P >or= 0.646). In conclusion, habitual volleyball players may be differentiated from their matched peers by their dynamic jumping performance, and the differences are reflected in the magnitude but not rate of loading.
一项给定运动的成骨作用可以通过计算由应变幅度和速率组成的成骨指数（OI）来估计。排球运动涉及反复跳跃，需要高功率输出，因此可能对骨骼和表现有益。本研究的目的是检验习惯性打排球是否反映在 OI 中。10 名老年习惯性排球运动员[年龄 69.9（SD 4.4）岁]和 10 名匹配的对照者自愿参加[年龄 69.7（4.2）岁]作为研究对象。使用 pQCT 和 DXA 测量远端胫骨（d）、胫骨中段（50）和股骨颈（FN）的骨特性。为了估计骨骼刚性，计算了横截面积（ToA(50)）以及压缩（BSI(d)）和弯曲强度指数（SSImax(50)）。最大性能通过离心踝跖屈、等长腿举和反向跳跃（CMJ）来评估。从 CMJ 期间质心的加速度计算出快速傅里叶变换（FFT）。选择最大加速度（MAG）和平均幅度频率（MMF）来代表 OI 的组成部分。OI 是幅度和相应频率的乘积之和。与匹配对照组相比，排球运动员的 ToA(50)大 7%，CMJ 功率高 37%，MAG 高 15%，OI 高 36%（P<0.047）。在腿举、跖屈或 MMF 方面没有差异（P>0.646）。总之，习惯性排球运动员可以通过他们的动态跳跃表现与他们的匹配同龄人区分开来，并且差异反映在幅度而不是加载率上。
