Correlation of Muscle Function and Bone Strain in the Hindlimb of the River Cooter Turtle (Pseudemys concinna)
Correlation of Muscle Function and Bone Strain in the Hindlimb of the River Cooter Turtle (Pseudemys concinna)
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DOI：
10.1002/jmor.20162
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发表时间：
2013-09-01
影响因子：
1.5
通讯作者：
Butcher, Michael T.
中科院分区：
文献类型：
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作者：
Aiello, Brett R.;Blob, Richard W.;Butcher, Michael T.
在地面运动时，肢体肌肉必须产生机械功并稳定关节以抵抗地面反作用力。这些要求可能需要高的力量产生，对肢体骨骼施加大量的负荷。为了更好地了解肌肉收缩功能如何影响陆地运动中骨负荷的模式，并完善用于估计肢体骨安全系数的力平台平衡模型，我们将一种物种（河龟，pseudomyys coninna）的股骨应变的体内记录与后肢主要推进肌胫骨内屈肌（FTI）的肌肉激活和应变进行了关联。肌电图（EMG）记录表明，FTI活动在足部之前持续了大约50%的站立阶段。当肌肉达到最大长度并开始主动缩短时，大的肌电图爆发发生在足后，同时股骨前部的压缩应变增加。FTI肌缩短35%的姿态，平均束缩短应变达到14.0 +/- 5.4%静息长度（L-0）。在股骨压缩应变达到峰值时，肌束仍保持活动，但随着膝关节的伸展，肌束通常会延长至站立中位。受膝背伸股胫肌活动的影响，FTI肌继续被动地延长，同时膝关节伸展，并在约40%的站立时向股骨前侧拉伸轴向应变转移。峰值骨压缩应变和峰值肌肉缩短的时间几乎一致（5.4 +/- 4.1%），表明髋伸肌/膝关节屈肌、FTI和股骨载荷在后肢内侧的作用密切相关。在四肢骨负荷平衡模型的背景下，这些结果可能有助于解释在先前的力平台和在体应变分析中观察到的安全系数估计的差异。中国生物医学工程学报，2014,34(4):559 - 564。(c) 2013 Wiley Periodicals, Inc.；
During terrestrial locomotion, limb muscles must generate mechanical work and stabilize joints against the ground reaction force. These demands can require high force production that imposes substantial loads on limb bones. To better understand how muscle contractile function influences patterns of bone loading in terrestrial locomotion, and refine force platform equilibrium models used to estimate limb bone safety factors, we correlated in vivo recordings of femoral strain with muscle activation and strain in a major propulsive hindlimb muscle, flexor tibialis internus (FTI), of a species with a published model of hindlimb force production (river cooter turtles, Pseudemys concinna). Electromyography (EMG) recordings indicate FTI activity prior to footfall that continues through approximately 50% of the stance phase. Large EMG bursts occur just after footfall when the muscle has reached its maximum length and is beginning to actively shorten, concurrent with increasing compressive strain on the anterior femur. The FTI muscle shortens through 35% of stance, with mean fascicle shortening strains reaching 14.0 +/- 5.4% resting length (L-0). At the time of peak compressive strains on the femur, the muscle fascicles remain active, but fascicles typically lengthen until mid-stance as the knee extends. Influenced by the activity of the dorsal knee extensor femorotibialis, the FTI muscle continues to passively lengthen simultaneously with knee extension and a shift to tensile axial strain on the anterior femur at approximately 40% of stance. The near coincidence in timing of peak compressive bone strain and peak muscle shortening (5.4 +/- 4.1% stance) indicates a close correlation between the action of the hip extensor/knee flexor, FTI, and femoral loading in the cooter hindlimb. In the context of equilibrium models of limb bone loading, these results may help explain differences in safety factor estimates observed between previous force platform and in vivo strain analyses in cooters. J. Morphol. 274:1060-1069, 2013. (c) 2013 Wiley Periodicals, Inc.