Anapol F C, Jungers W L
Am J Phys Anthropol. 1986 Mar;69(3):355-75. doi: 10.1002/ajpa.1330690308.
Physiologically related features of muscle morphology are considered with regard to functional adaptation for locomotor and postural behavior in the brown lemur (Lemur fulvus). Reduced physiological cross-sectional area, estimated maximum excursion of the tendon of insertion, length of tendon per muscle fasciculus, and areal fiber type composition were examined in the quadriceps femoris in order to assess the extent of a "division of labor" among four apparent synergists. Each of these four muscles in this prosimian primate displays a distinguishing constellation of morphological features that implies functional specialization during posture and normal locomotion (walk/run, galloping, leaping). Vastus medialis is best suited for rapid whole muscle recruitment and may be reserved for relatively vigorous activities such as galloping and leaping (e.g., small cross-sectional area per mass, long excursion, predominance of fast-low oxidative fibers, relatively little tendon per fasciculus). In theory, rectus femoris could be employed isometrically in order to store elastic strain energy during all phasic activities (e.g., large cross-sectional area per mass, short excursion, predominance of fast-high oxidative fibers, large amount of tendon per fasciculus). Vastus intermedius exhibits an overall morphology indicative of a typical postural muscle (e.g., substantial cross-sectional area, short excursion, predominance of slow-high oxidative fibers, large amount of tendon per fasciculus). The construction of vastus lateralis reflects an adaptation for high force, relatively high velocity, and resistance to fatigue (e.g., large cross-sectional area, long excursion, most heterogeneous distribution of fiber types, large amount of tendon per fasciculus); this muscle is probably the primary contributor to a wide range of locomotor behaviors in lemurs. Marked dramatic architectural disparity among the four bellies, coupled with relative overall fiber type heterogeneity, suggests the potential for exceptional flexibility in muscle recruitment within this mass. One interpretation of this relatively complex neuromuscular organization in the brown lemur is that it represents an adaptation for the exploitation of a three-dimensional arboreal environment by rapid quadrupedalism and leaping among irregular and spatially disordered substrates.
关于褐狐猴（Lemur fulvus）运动和姿势行为的功能适应性，研究了肌肉形态的生理相关特征。为了评估四块明显协同肌之间“分工”的程度，对股四头肌的生理横截面积、插入肌腱的估计最大伸展幅度、每束肌纤维的肌腱长度以及肌纤维类型的面积组成进行了检查。在这种原猴亚目灵长类动物中，这四块肌肉中的每一块都呈现出独特的形态特征组合，这意味着在姿势和正常运动（行走/奔跑、疾驰、跳跃）过程中具有功能特化。股内侧肌最适合快速整体募集，可能用于相对剧烈的活动，如疾驰和跳跃（例如，单位质量的横截面积小、伸展幅度长、快速低氧化纤维占优势、每束肌纤维的肌腱相对较少）。理论上，股直肌可以等长收缩，以便在所有相位活动中储存弹性应变能（例如，单位质量的横截面积大、伸展幅度短、快速高氧化纤维占优势、每束肌纤维的肌腱量大）。股中间肌呈现出的整体形态表明它是典型的姿势肌（例如，横截面积大、伸展幅度短、慢速高氧化纤维占优势、每束肌纤维的肌腱量大）。股外侧肌的结构反映了对高力量、相对高速度和抗疲劳的适应（例如，横截面积大、伸展幅度长、纤维类型分布最不均匀、每束肌纤维的肌腱量大）；这块肌肉可能是狐猴广泛运动行为的主要贡献者。四块肌腹之间明显的显著结构差异，再加上相对整体的纤维类型异质性，表明在这个肌群内肌肉募集具有非凡灵活性的潜力。对褐狐猴这种相对复杂的神经肌肉组织的一种解释是，它代表了一种适应，通过在不规则和空间无序的基质之间快速四足行走和跳跃来利用三维树栖环境。
