Orizio C, Veicsteinas A
Dipartimento di Scienze Biomediche e Biotecnologie, Università di Brescia, Italy.
Int J Sports Med. 1992 Nov;13(8):594-9. doi: 10.1055/s-2007-1024572.
The aim of this study was to describe the influence of the different fiber type composition of the vastus lateralis muscle on the soundmyogram (SMG) time and frequency domain characteristics. The SMG was recorded from the vastus lateralis belly during exhausting maximal voluntary contraction (MVC) of the leg extensors in 7 sprinters (SPR) and 7 long distance runners (LDR). Seven sedentary males (SED) were investigated in the same experimental conditions. In the SPR the effort time was shorter and the MVC was greater while the SMG root mean square and the SMG frequency content, at the onset of contraction, were higher than in the SED and LDR, respectively. Throughout exertion the SMG RMS showed clear reduction for SPR and SED only and the SMG power spectra presented a compression towards the lower frequencies. The reported phenomena were less pronounced in the LDR than in SPR and SED. These results can be explained when the differences in the % of fast twitch fibers area, belonging to stronger and more fatiguing F motor units, in the three groups of subjects are considered and suggest that SMG characteristics reflect the muscle fiber typing.
本研究旨在描述股外侧肌不同纤维类型组成对肌音图（SMG）时域和频域特征的影响。在7名短跑运动员（SPR）和7名长跑运动员（LDR）进行腿部伸肌力竭性最大自主收缩（MVC）时，从股外侧肌肌腹记录SMG。在相同实验条件下对7名久坐男性（SED）进行了研究。在SPR中，用力时间较短，MVC较大，而在收缩开始时，SMG均方根和SMG频率含量分别高于SED和LDR。在整个运动过程中，仅SPR和SED的SMG均方根明显降低，并且SMG功率谱呈现向低频的压缩。LDR中报告的现象不如SPR和SED中明显。当考虑三组受试者中属于更强壮且更易疲劳的F运动单位的快肌纤维面积百分比差异时，可以解释这些结果，并表明SMG特征反映了肌纤维类型。
