Forms of forward quadrupedal locomotion. II. A comparison of posture, hindlimb kinematics, and motor patterns for upslope and level walking
Forms of forward quadrupedal locomotion. II. A comparison of posture, hindlimb kinematics, and motor patterns for upslope and level walking
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DOI：
10.1152/jn.1998.79.4.1687
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发表时间：
1998-04-01
影响因子：
2.5
通讯作者：
Smith, JL
中科院分区：
文献类型：
--
作者：
Carlson-Kuhta, P;Trank, TV;Smith, JL
为了深入了解控制正常猫不同形式四足行走的神经机制，对从 25% 到 100%（45 度倾斜）的四个等级的上坡行走的姿势定向、后肢运动学和选定后肢肌肉的运动模式的数据进行了评估，并与水平跑步机行走（0.6 m/s）的类似数据进行了比较。髋关节、膝关节、踝关节和跖趾关节的运动数据通过数字化电影胶片获得，该胶片与 13 个不同后肢肌肉的肌电图 (EMG) 记录同步。所有年级的循环周期、步态循环结构和爪子接触顺序都是相似的，并且是横向顺序行走的典型特征。此外，还从 100% 等级的试验中评估了一些半跳和横向驰骋步；这些步骤的循环周期比步行步骤短，并且循环中用于站立的时间也更少（68% vs. 56%）。每只猫在上坡行走的坡度较陡时都采取蹲伏的姿势，步幅长度减小，而步幅的整体位置相对于髋关节向尾部移动。在较陡的坡度上，所有关节与摆动相关的屈曲范围和持续时间都增加，膝关节和踝关节的站立相屈服不存在，而膝关节和踝关节的站立相伸展范围增加。上坡和平走的肌肉活动模式相似，但有一些明显的例外。在较陡的坡度上，具有摆动相关活动的肌肉，如指屈肌、指长屈肌 (FDL) 和膝屈肌、半腱肌 (ST)，其肌电图活动延长并持续到摆动中期：与站立相关的肌肉的肌电图活动幅度也随着坡度的增加而增加，在水平行走的站立阶段不活动的三块肌肉的站立活动在最陡坡度处的幅度和持续时间都增加；这些肌肉是 ST、FDL 和趾短伸肌。总体而言，上坡行走过程中姿势、后肢运动学和后肢肌肉活动模式的变化反映了在站立过程中不断向前和向上移动身体质量的需要，并确保在摆动过程中爪子越过倾斜的斜坡。讨论了这些变化对行走神经控制的影响以及斜坡行走后肢动力学的预期变化。
To gain insight into the neural mechanisms controlling different forms of quadrupedal walking of normal cats, data on postural orientation, hindlimb kinematics, and motor patterns of selected hindlimb muscles were assessed for four grades of upslope walking, from 25 to 100% (45 degrees incline), and compared with similar data for level treadmill walking (0.6 m/s). Kinematic data for the hip, knee, ankle, and metatarsophalangeal joints were obtained from digitizing cine film that was synchronized with electromyographic (EMG) records from 13 different hindlimb muscles. Cycle periods, the structure of the step cycle, and paw-contact sequences were similar at all grades and typical of lateral-sequence walking. Also, a few half-bound and transverse gallop steps were assessed from trials at the 100% grade; these steps had shorter cycle periods than the walking steps and less of the cycle (68 vs. 56%) was devoted to stance. Each cat assumed a crouched posture at the steeper grades of upslope walking and stride length decreased, whereas the overall position of the stride shifted caudally with respect to the hip joint. At the steeper grades, the range and duration of swing-related flexion increased at all joints, the stance-phase yield was absent at the knee and ankle joints, and the range of stance-phase extension at knee and ankle joints increased. Patterns of muscle activity for upslope and level walking were similar with some notable exceptions. At the steeper grades, the EMG activity of muscles with swing-related activity, such as the digit flexor muscle, the flexor digitorum longus (FDL), and the knee flexor muscle, the semitendinosus (ST), was prolonged and continued well into midswing: The EMG activity of stance-related muscles also increased in amplitude with grade, and three muscles not active during the stance phase of level walking had stance activity that increased in amplitude and duration at the steepest grades; these muscles were the ST, FDL, and extensor digitorum brevis. Overall the changes in posture, hindlimb kinematics, and the activity patterns of hindlimb muscles during upslope walking reflected the need to continually move the body mass forward and upward during stance and to ensure that the paw cleared the inclined slope during swing. The implications of these changes for the neural control of walking and expected changes in hindlimb kinetics for slope walking are discussed.