Yamauchi Koun, Someya Keita, Kato Chisato, Kato Takayuki
Department of Orthopaedic Surgery, Akita Hospital, Chiryu, 2-6-12 Takara, Chiryu, Aichi, 472-0056, Japan.
Department of Radiology, Akita Hospital, 2-6-12 Takara, Chiryu, Aichi, 472-0056, Japan.
Eur J Appl Physiol. 2025 Feb 1. doi: 10.1007/s00421-025-05719-z.
Whether stretch exercise improves muscle anisotropy in relation to intramuscular adipose tissue (IntraMAT) is unclear. This study aimed to compare the diffusion tensor imaging (DTI) parameters of the quadriceps before and after stretching and to investigate correlations between the magnitudes of changes and IntraMAT ratios.
Twenty young males were included. Single axial DTI and T1-weighted imaging of the right mid-thigh region were conducted before and after rest and stretching. Individual quadriceps were segmented, λ and fractional anisotropy (FA) were measured using DTI, and the IntraMAT ratios were measured using T1-weighted imaging. To test an intervention-by-time interaction effect, two-way repeated-measures analysis of variance was conducted. The correlation coefficients between the changing λ and FA magnitude by stretching and the IntaMAT ratio were assessed.
There was a significant interventions-by-time interaction effect in the λ and FA in the vastus medialis (VM). After stretching, in the VM, the λ values significantly decreased (mean difference, 0.07 mm∙s∙10 for λ), and the FA significantly increased (mean difference, 0.021). Furthermore, the decreasing λ and λ in the VM were significantly inversely correlated with the IntraMAT ratio (r = - 0.50 for both), and the increasing FA magnitude was significantly positively correlated with the IntraMAT ratio (r = 0.45).
Stretching the quadriceps acutely decreased λ and increased FA in the VM, and the magnitude of the λ, λ, and FA changes were correlated with the IntraMAT ratio. Stretching the quadriceps could improve VM function, particularly in overweight and obese people.
拉伸运动是否能改善与肌内脂肪组织（IntraMAT）相关的肌肉各向异性尚不清楚。本研究旨在比较拉伸前后股四头肌的扩散张量成像（DTI）参数，并研究变化幅度与IntraMAT比率之间的相关性。
纳入20名年轻男性。在休息和拉伸前后对右大腿中部区域进行单轴DTI和T1加权成像。对个体股四头肌进行分割，使用DTI测量λ和分数各向异性（FA），并使用T1加权成像测量IntraMAT比率。为了检验干预-时间交互效应，进行了双向重复测量方差分析。评估拉伸引起的λ和FA变化幅度与IntaMAT比率之间的相关系数。
股内侧肌（VM）的λ和FA存在显著的干预-时间交互效应。拉伸后，VM的λ值显著降低（λ的平均差异为0.07mm∙s∙10），FA显著增加（平均差异为0.021）。此外，VM中λ的降低与IntraMAT比率显著负相关（两者r = - 0.50），FA增加幅度与IntraMAT比率显著正相关（r = 0.45）。
急性拉伸股四头肌可使VM的λ降低、FA增加，且λ、λ和FA的变化幅度与IntraMAT比率相关。拉伸股四头肌可改善VM功能，尤其是对超重和肥胖人群。
