Spine and lower body symmetry during treadmill walking in healthy individuals-In-vivo 3-dimensional kinematic analysis

Abstract

Although it is relevant to understand spine and lower body motions in healthy individuals for a variety of applications, such as clinical diagnosis, implant design, and the analysis of treatment outcomes, proper assessment and characterization of normative gait symmetry in healthy individuals remains unclear. The purpose of this study was to investigate the in vivo 3-dimensional (3D) spine and lower body gait symmetry kinematics during treadmill walking in healthy individuals. Sixty healthy young adults (30 males and 30 females) were evaluated during normal and fast treadmill walking using a motion capture system approach. Statistical parametric mapping and the normalized symmetry index approaches were used to determine spine, pelvis, and lower body asymmetries during treadmill walking. The spine and pelvis angular motions associated with the left and right lower limb motions, as well as the left and right lower extremity joint angles were compared for normal and fast treadmill walking. The lower lumbar left-right rotation (5.74±0.04°) and hip internal rotation (5.33±0.18°) presented the largest degrees of asymmetry during normal treadmill. Upper lumbar left-right lateral flexion (1.48±0.14°) and knee flexion (2.98±0.13°) indicated the largest asymmetries and during fast treadmill walking. Few asymmetry patterns were similar between normal and fast treadmill walking, whereas others appeared either only during normal or fast treadmill walking in this cohort of participants. These findings could provide insights into better understanding gait asymmetry in healthy individuals, and use them as reference indicators in diagnosing and evaluating abnormal gait function.

Fig 1. Spine and lower body marker set.

Prefixes denote the following: L: Left, R: Right, U: Upper, Lw: Lower, Lt: Lateral, and M: Medial. The following landmarks were used: Spinous process at T1 (T1), spinous process at T6 (T6), spinous process at L1(L1), spinous process at L3 (L3), spinous process at L5 (L5), thorax (TH), lumbar (LB), anterior superior iliac spine (ASI), posterior superior iliac spine (PSI), femur (THI), epicondyle of femur (KN), tibia (TB), malleoli (AK), and foot (FT).

Fig 2. Three-dimensional coordinate systems defined for upper thorax, lower thorax, upper lumbar, lower lumbar, pelvis, left and right thigh, left and right tibia, and left and right foot segments.

Local z axes were determined between T1 and T6, T6 and L1, L1 and L3, and L3 and L5 for upper thorax, lower thorax, upper lumbar, and lower lumbar segments, respectively. Cross product of the z axis and the vector defined by the two midpoint markers determined the x axis of each spine segment. Joint angles defined for the upper thorax, lower thorax, upper lumbar, and lower lumbar. The left and right anterior superior iliac spine (ASIS) and posterior superior iliac spine (PSIS) markers defined the local pelvis axes, with the y axis defined between left and right ASIS, and the x axis pointing anteriorly. Anatomical hip, knee, ankle joint axes were projected on thigh, tibia, and foot clusters, respectively, with the local z axis along the long axis of the femur, tibia, and foot, and the local y axis pointing laterally.

Fig 3. Average and standard deviation of upper thorax, lower thorax, upper lumbar, and lower lumbar flexion-extension (F/E), left-right (L/R) lateral flexion, and (L/R) rotation, for left and right sides during one gait cycle of normal treadmill walking (TWN) in sixty healthy participants.

Green bars on the horizontal axis and the scalar field SPM results with threshold t* depict where, in % cycle, left side angles were greater or lesser than right side angles. The normalized symmetry index (SI_norm) calculated during one gait cycle of TWN. Solid and dashed lines correspond to average left and right sides, as well as average SI_norm, and shaded areas correspond to standard deviation. Black dotted vertical lines denote toe-off.

Fig 4. Average and standard deviation of upper thorax, lower thorax, upper lumbar, and lower lumbar flexion-extension (F/E), left-right (L/R) lateral flexion, and (L/R) rotation, for left and right sides during one gait cycle of fast treadmill walking (TWF) in sixty healthy participants.

Green bars on the horizontal axis and the scalar field SPM results with threshold t* depict where, in % cycle, left side angles were greater or lesser than right side angles. The normalized symmetry index (SI_norm) calculated during one gait cycle of TWF. Solid and dashed lines correspond to average left and right sides, as well as average SI_norm, and shaded areas correspond to standard deviation. Black dotted vertical lines denote toe-off.

Fig 5. Average and standard deviation of pelvis posterior-anterior (P/A) tilt, left-right(L/R) obliquity, and (L/R) rotation, hip and knee flexion-extension (F/E), adduction-abduction (Ad/Ab), and internal-external (Int/Ext) rotation, and ankle dorsi-plantar flexion (DF/PF), eversion-inversion (Eve/Inv), and internal-external (Int/Ext) rotation for left and right sides during one gait cycle of normal treadmill walking (TWN) in sixty healthy participants.

Green bars on the horizontal axis and the scalar field SPM results with threshold t* t depict where, in % cycle, left side angles were greater or lesser than right side angles. The normalized symmetry index (SI_norm) calculated during one gait cycle of TWN. Solid and dashed lines correspond to average left and right sides, as well as average SI_norm, and shaded areas correspond to standard deviation. Black dotted vertical lines denote toe-off.

Fig 6. Average and standard deviation of pelvis posterior-anterior (P/A) tilt, left-right (L/R) obliquity, and (L/R) rotation, hip and knee flexion-extension (F/E), adduction-abduction (Ad/Ab), and internal-external (Int/Ext) rotation, and ankle dorsi-plantar flexion (DF/PF), eversion-inversion (Eve/Inv), and internal-external (Int/Ext) rotation for left and right sides during one gait cycle of normal treadmill walking (TWN) in sixty healthy participants.

Green bars on the horizontal axis and the scalar field SPM results with threshold t* t depict where, in % cycle, left side angles were greater or lesser than right side angles. The normalized symmetry index (SI_norm) calculated during one gait cycle of TWN. Solid and dashed lines correspond to average left and right sides, as well as average SI_norm, and shaded areas correspond to standard deviation. Black dotted vertical lines denote toe-off.