Stance Phase Of Normal Walking Research Articles

Effect of Cognitive Training on Lower Limb Muscular Activity in Older Adults With Balance Impairment During Walking

Purpose: The purpose of this study was to compare the effects of two different approaches of dual-task training and executive training on lower limb muscular activity in older adults with balance impairment. Methods: This was a quasi-experimental study performed with a pre-test and post-test method. Thirty old adults (Mean±SD age=73.8±4.6 y, height=1.65±0.06 m, weight=69.17±12.67 kg) were randomly assigned to one of the three groups: two experimental groups included Cognitive Dual-Task training (CDT; participants did exercises under the dual-task condition with cognitive tasks, such as forward counting, simple visual search task, etc.) and Executive Function training (EF; included a mixture of 20 tasks involving working memory tasks, inhibitory and speed of processing tasks), and a control group. The training session lasted 45 min and was held three times a week for eight weeks. Gait muscle activity under single-task and Dual-Task (DT) conditions was recorded before and after training. Results: during the stance phase of normal walking, the amplitude of Electromyography (EMG) activity of right Tibialis Anterior (TA) muscle in the post-test was about 32% lower than that in the pre-test in the CDT group (P=0.011), and no statistically significant change was between pre- and post-training in the EF and control groups (P>0.05). During the swing phase of DT walking, the amplitude of EMG activity of the right Vastus Lateralis (VL) muscle in the post-test was about 15.5% higher than that in the pre-test in the CDT group (P=0.013), and in the right VL muscle during the post-test was lower than that in the pre-test in the EF group (P=0.01). In the CDT group, right ankle co-contraction during the stance phase in the post-test was statistically different from that in the pre-test. In all three groups, muscular EMG asymmetry demonstrated no statistically significant change between pre- and post-training measures (P>0.05). Conclusion: Overall, both training groups showed similar muscular activity in the post-test than pre-test; however, in the EF training group, walking velocity improved more than that in the CDT group. Therefore, because of improvements in both walking velocity and muscle activities after EF training, this training mode is suggested for older adults.

Influence of Ligament Properties on Tibiofemoral Mechanics in Walking.

Computational knee models provide a powerful platform to investigate the effects of injury and surgery on functional knee behavior. The objective of this study was to use a multibody knee model to investigate the influence of ligament properties on tibiofemoral kinematics and cartilage contact pressures in the stance phase of walking. The knee model included 14 ligament bundles and articular cartilage contact acting across the tibiofemoral and patellofemoral joints. The knee was incorporated into a lower extremity musculoskeletal model and was used to simulate knee mechanics during the stance phase of normal walking. A Monte Carlo approach was employed to assess the influence of ligament stiffness and reference strain on knee mechanics. The anterior cruciate ligament (ACL), medial collateral ligament (MCL), and posterior capsule properties exhibited significant influence on anterior tibial translation at heel strike, with the ACL acting as the primary restraint to anterior translation in mid-stance. The MCL and lateral collateral ligament (LCL) exhibited the greatest influence on tibial rotation from heel strike through mid-stance. Simulated tibial plateau contact location was dependent on the ACL, MCL, and LCL properties, while pressure magnitudes were most dependent on the ACL. A decrease in ACL stiffness or reference strain significantly increased the average contact pressure in mid-stance, with the pressure migrating posteriorly on the medial tibial plateau. These ligament-dependent shifts in tibiofemoral cartilage contact during walking are potentially relevant to consider when investigating the causes of early-onset osteoarthritis following knee ligament injury and surgical treatment.

A study of foot and ankle kinematics during stance phase of normal walking

The study of foot and ankle kinematics is important in clinical cases such as abnormal foot functions and foot deformities. The objective of this study is to investigate kinematics of foot and ankle during stance phase of normal walking. This kinematic study includes joint motions between five rigid foot segments with new reference positions, and four new functional angles for describing physical features of walking. The results show that time-histories of the five joint motions present good agreement with previous literature. The new reference positions perform well for reducing variance among subjects. The results of four functional angles are consistent with gait and can more intuitively describe foot function features with good intra-subject repeatability. This study provides a comprehensive understanding of foot and ankle motions during stance phase of normal walking.

Temporal couplings between rearfoot–shank complex and hip joint during walking

Background Rearfoot pronation–supination and hip internal–external rotation are commonly assumed to be temporally coupled. Many mechanisms of musculoskeletal injury are proposed based on this assumption. Previous studies suggested that this theoretical coupling does not exist. However, recent experimental studies observed relationships consistent with foot–hip mechanical interdependence. Methods Three-dimensional kinematics of the lower extremity of 18 healthy subjects, wearing flat trekking sandals, was measured during the stance phase of normal walking. Rearfoot–shank complex motion in the transverse plane (shank internal–external rotation) and frontal plane (rearfoot eversion–inversion) and hip motion in the transverse plane were analyzed. Cross-correlation coefficients were calculated to investigate temporal similarities between curves of rearfoot–shank and hip motions. Pearson correlations were used to investigate relationships between the timings of the peaks of these motions. Findings Cross-correlations revealed a strong mean temporal coupling (mean r = 0.77, range 0.56 to 0.92) between shank internal–external rotation and hip internal–external rotation and a moderate mean temporal coupling (mean r = 0.56, range 0.37 to 0.78) between rearfoot eversion–inversion and hip internal–external rotation. Pearson correlations revealed significant ( P ≤ 0.031) moderate relationships of timing of peak shank internal rotation ( r = 0.45) and timing of peak rearfoot eversion ( r = 0.62) with timing of peak hip internal rotation. Interpretation The findings suggest a temporal coupling of rearfoot pronation with hip internal rotation and rearfoot supination with hip external rotation during walking stance. The between-subjects variability of curves' temporal similarities and the moderate relationships between timings of motion peaks indicate that coupling strength should be clinically addressed on an individual basis.

The impact of adding trunk motion to the interpretation of the role of joint moments during normal walking

Biomechanical model assumptions affect the interpretation of the role of the muscle or joint moments to the segmental power estimated by induced acceleration analysis (IAA). We evaluated the effect of modeling the pelvis and trunk segments as two separate segments (8 SM) versus as a single segment (7 SM) on the segmental power, support of the body, knee and hip extension acceleration produced by the joint moments during the stance phase of normal walking. Significant differences were observed in the contribution of the stance hip abductor and extensor moments to support, ipsilateral knee and hip acceleration, and ipsilateral thigh and upper body power. The primary finding was that the role of the stance hip moment in generating ipsilateral thigh and upper body power differed based on degrees of freedom in the model. Secondarily, the magnitude of contributions also differed. For example, the hip abductor and extensor moments showed greater contribution to support, hip and knee acceleration in the 8 SM. IAA and segment power analysis are sensitive to the degrees of freedom between the pelvis and trunk. There is currently no gold standard by which to evaluate the accuracy of IAA predictions. However, modeling the pelvis and trunk as separate segments is closer to the anatomical architecture of the body. An 8 SM appears to be more appropriate for estimating the role of joint moments, particularly to motion of more proximal segments during normal walking.

VELOCITY OF PLANTAR PRESSURE TRAJECTORY - A USEFUL TOOL TO DIFFER PROFESSIONAL BALLET DANCER

INTRODUCTION Foot disorders are common among ballet dancers, and these problems may alter gait patterns during level walking. Clinical gait analysis aims to quantify and assess walking mechanics, and facilitates identification of deviations from normal movement patterns. However, there are relatively few studies where quantitative gait analysis has been used to investigate the relationship between professional ballet training and walking patterns. The velocity of the center of pressure (CoP) can be computed and follows a predictable pattern during the stance phase of normal walking [1].The purpose of this study is to investigate the differences of CoP velocity duirng normal walking between dancers and non-dancers. The results of this study may provide useful suggestions for accommodating the gait pattern in dancers and reducing the possibility of foot injury in daily situations.

Muscle activation profiles about the knee during Tai-Chi stepping movement compared to the normal gait step

The purpose of this study was to investigate knee muscle activity patterns in experienced Tai-Chi (TC) practitioners during normal walking and TC stepping. The electromyographic (EMG) activity of vastus lateralis (VL), vastus medialis (VM), bicep femoris (BF), and gastrocnemius (GS) muscles of 11 subjects (five females and six males) during the stance phase of normal walking was compared to stance phase of a TC step. Knee joint motion was also monitored by using an Optotrak™motion analysis system. Raw EMG was processed by root-mean-square (RMS) technique using a time constant of 50 ms, and normalized to maximum of voluntary contraction for each muscle, referred to as normalized RMS (nRMS). Peak nRMS and co-contraction (quantified by co-contraction index) during stance phase of a gait cycle and a TC step were calculated. Paired t-tests were used to compare the difference for each muscle group peak and co-contraction pair between the tasks. The results showed that only peak values of nRMS in quadriceps and co-contraction were significantly greater in TC stepping compared to normal walking (Peak values of nRMS for VL were 26.93% for normal walking and 52.14% for TC step, p = 0.001; VM are 29.12% for normal walking and 51.93% for TC stepping, p = 0.028). Mean co-contraction index for VL–BF muscle pairs was 13.24 ± 11.02% during TC stepping and 9.47 ± 7.77% in stance phase of normal walking ( p = 0.023). There was no significant difference in peak values of nRMS in the other two muscles during TC stepping compared to normal walking. Preliminary EMG profiles in this study demonstrated that experienced TC practitioners used relatively higher levels of knee muscle activation patterns with greater co-contraction during TC exercise compared to normal walking.

Relative movement of the navicular bone during normal walking.

The purpose of this study was to determine the pattern and magnitude of navicular bone (NB) movement during walking as well as the relationship between dynamic NB and rearfoot movement. The angle of rearfoot and displacement of the NB was recorded in 106 subjects using the 6D Research electromagnetic tracking system. The relative change in the height of the NB between foot flat and heel-off was 7.9 mm. The NB seems to undergo significant vertical as well as medial displacement during the stance phase of normal walking. This motion is also correlated with rearfoot motion during walking.

Footwear and foot orthotic effectiveness research: a new approach.

Measurement of calcaneal inversion and eversion during walking is limited when subjects wear shoes. The authors of this study propose the use of transverse tibial rotation as a viable alternative measurement when barefoot assessment is not possible. The purpose of this study, therefore, was to: 1) determine the relationship between transverse tibial rotation and rearfoot motion during the stance phase of normal walking and 2) demonstrate the usefulness of measuring transverse tibial rotation when evaluating the effect of footwear and insole foot orthotic devices. Part 1 consisted of eight volunteers (five women, three men) whose rearfoot and transverse tibial motion was videotaped while they walked along a 12-m walkway. The results of this study showed that although absolute values were not comparable, the two motion patterns are related to each other. The correlation between the mean rearfoot and tibial motion patterns of all 16 feet was r = .953. Part 2 investigated the effect of footwear and orthotics on transverse tibial rotation using two case presentations. A video camera was positioned in front of each subject as they walked at a self-selected speed under various footwear or orthotic conditions. The results of the case studies revealed that footwear or foot orthotics decrease maximum tibial internal rotation compared with barefoot walking. In addition, internal tibial rotation velocity and acceleration were decreased by the use of shoes, an accommodative orthosis, and an inflatable medial longitudinal arch support. A rigid orthotic produced a slight increase in transverse tibial rotation and a dramatic increase in transverse tibial acceleration.(ABSTRACT TRUNCATED AT 250 WORDS)

Performance objectives in human movement: A review and application to the stance phase of normal walking

That some form of optimisation takes place in skilled human movements may be inferred from metabolic, electromyographic and perceptual experimental results. However, the parameter(s) or function(s) minimised in activities such as walking has not been satisfactorily identified. This work used non-linear optimal control and multiple-segment simulation software to evaluate the predictive ability of seven performance objective functions. The results indicated that minimisation of the time integrals of the sums of the joint torques, the segmental angular accelerations, or the segmental mechanical energies produced the best simulations of the single stance phase of walking. Strong support was also provided for the existence of simultaneous multiple performance objectives in complex movements.