The coordination of upper and lower limbs in curve-turning walking of healthy preschoolers: Viewed in continuous relative phase

Coordination strategies of lower limb muscles during curve-turning tasks in preschool children

BACKGROUND

Preschoolers are within their critical time in motion development; while muscles are the fundamental units in motion control and by monitoring activated intensity and duration of muscles, preschooler's motor ability which would disclose their potential pathogenesis quality can be objectively and quantitatively assessed. Although a large number of studies were available on this issue, questions still being there: what are the patterns and characteristics of lower limb muscles when they are facing with the curve walking(CW) tasks; and then how individual muscle or muscle groups coordinated while turning curves. Our purpose of this study is first to portray the patterns and characteristics of lower limb muscles of healthy preschoolers while CW and then to insight their muscles' coordination mechanism and "neuro-musculo-skeletal" feedback during motion.

METHOD

35 healthy preschoolers and 35 healthy adults' lower limbs surface electromyography (sEMG) were collected while left and right CW and four muscle groups (Tibialis Anterior, Lateral Gastrocnemius, Rectus Femoris, and Biceps Femoris) were recorded. sEMG variables such as Muscle Activation Time, Total Duration of Activity Time, Average Muscle Activation Rate and Average Rate of Change were calculated. Paired sample t-test was used to explore the differences of sEMG variables between preschoolers and adults when turning curves.

RESULTS

Preschoolers would adjust the gait by changing the activation time and activation rate to fulfill the curve turning tasks; but they also showed variations in coordination mechanism when contrasting with the adults group. Those findings in preschoolers would support to build muscles' coordination mechanism and further insight to neuro-muscular skeletal feedback regulation.

CONCLUSION

Although preschoolers performed good enough to switching gait from normal walking to CW, but gaps in their abilities were still apparent when compared to adults. Hence, with the help of highly recognizable muscle coordination mechanism in CW, motor dysfunction in lower limbs of preschool children can be effectively identified.

Acute effects of Kinesio Taping on lower-limb coordination of gait in hemiplegic patients

BACKGROUND

Kinesio taping can effectively strengthen weakened muscles, increase walking speed, and improve dynamic balance in hemiplegic patients, but its effect on lower-limb coordination is not clear. Improving lower-limb coordination in hemiplegic patients can decrease risk of fall during walking.

RESEARCH QUESTION

This study utilized continuous relative phase to depict the pattern and variability of lower-limb coordination in hemiplegic patients and healthy subjects during walking, and investigate whether it has the acute effect of Kinesio Taping on lower-limb coordination in hemiplegic patients during walking.

METHODS

Gait was measured by a three-dimensional motion capture system for 29 hemiplegic patients (KT group) and 15 healthy subjects (control group). Mean continuous relative phase (MCRP) and mean continuous relative phase variability (MCRPV) were calculated to describe and evaluate lower-limb coordination.

RESULTS

KT intervention only changed the coordination between the bilateral ankle joints in hemiplegic patients. Before the intervention, the MCRP of the two ankles (AA-MCRP) in the stance period of the control group was greater than the KT group (P < 0.001), the MCRPV of the two ankles (AA-MCRPV) in the swing period was lower than that in KT group (P < 0.001). After the intervention, the AA-MCRP in the stance period of the KT group increased (P < 0.001), the AA-MRPV in the swing period of KT group significantly decreased (P = 0.001).

SIGNIFICANCE

Immediate ankle KT intervention can result in the in-phase or anti-phase coordination between the two ankles developing to out-of-phase coordination during the stance period of the affected limb during walking, and increase the stability of the out-of-phase coordination between the two ankles during the swing period of the affected limb. KT can be used in rehabilitation treatment for hemiplegic patients to improve acute coordination between the patients' ankles.

Lower limbs inter-joint coordination and variability during typical Tai Chi movement in older female adults

Purpose: This study aimed to investigate the lower limb inter-joint coordination and variability during Tai Chi movements compared with normal walking in older adults. Methods: A total of 30 female Tai Chi practitioners (70.9 ± 5.2 years) were recruited in this study. Herein, each participant performed three trials of the normal walking and Tai Chi movements. The lower limb kinematics data were collected with Vicon 3D motion capture system. The continuous relative phase (CRP) includes both spatial and temporal information of two adjacent joints, which was calculated to assess the inter-joint coordination of lower limbs. Coordination amplitude and coordination variability were assessed with mean absolute relative phase (MARP) and deviation phase (DP). MANOVOA was used to analyze inter-joint coordination parameters between different movements. Results: The CRP values of hip-knee and knee-ankle segments in the sagittal plane of the Tai Chi movements changed frequently. The MARP values of the hip-knee (p < 0.001) and knee-ankle segments (p = 0.032) as well as the DP values of the hip-knee segment (p < 0.001) were significantly lower in Tai Chi than in normal walking. Conclusion: More consistent and stable inter-joint coordination patterns of Tai Chi movements found in this study may be one of the critical factors that Tai Chi could be a suitable coordinated exercise for older adults.

PORTRAIT AND HILBERT TRANSFORM METHODS FOR EVALUATING CONTINUOUS RELATIVE PHASE BETWEEN LOWER-LIMB JOINTS IN THE ELDERLY DURING WALKING

In order to calculate the continuous relative phase (CRP) between joints, the portrait method based on the joint angle and angular velocity and the Hilbert transform method based on the analytical signal have been widely used. However, there are few comparisons of these methods. Therefore, the aim of this study is to quantitatively compare these methods by calculating the CRP in the lower-limb joints of the elderly during level free walking. Eighteen elderly female adults ([Formula: see text] year-old, [Formula: see text][Formula: see text]cm, [Formula: see text][Formula: see text]kg) wearing a Helen Hayes full-body marker set walked 10[Formula: see text]m on level ground at a self-selected velocity. The angles of the hip, knee, and ankle were measured. To calculate the CRP using the portrait method, the angular velocities were measured. Then, the phases between the angle and the angular velocity were calculated. To calculate the CRP using the Hilbert transform method, analytical signals were acquired. Then, the phases between the real and imaginary parts were calculated. A CRP was calculated as the difference between the phase in the proximal joint and the phase in the distal joint. To evaluate the similarity in the shape between the portrait and Hilbert transform methods, the cross-correlation was calculated. Bland–Altman plot analyses were performed to assess the agreement between these methods. For the root mean squares (RMSs) and standard deviations (SDs), a paired [Formula: see text]-test and the Pearson correlation between methods were evaluated. There were similarities in the in-phase or out-of-phase features and in the RMS and SD between the methods. Additionally, a higher cross-correlation and agreement between them were found. These results indicated the similarity between the portrait and Hilbert transform methods for the calculation of the CRP. Therefore, either method can be used to evaluate joint coordination.

Coordination of lower limbs in patients with knee osteoarthritis during walking

BACKGROUND

The movement coordination in patients with knee osteoarthritis may be impaired and the identification of the deficits in lower limb inter-segmental coordination is crucial to understand the effect of knee osteoarthritis on knee function.

RESEARCH QUESTION

This study utilizes continuous relative phase to investigate the pattern and variability of lower limb inter-segmental coordination in patients with knee osteoarthritis and in healthy subjects during walking, and to evaluate inter-segmental coordination alterations in patients.

METHODS

Gait was measured by a three-dimensional motion capture system for 44 patients with late-stage knee osteoarthritis and 22 healthy subjects. Segmental kinematic parameters, continuous relative phase and its variability were calculated. Independent samples t-tests were used to detect differences between patients and healthy subjects.

RESULTS

Thigh-shank continuous relative phase of patients is significantly decreased by 16.04° and 16.18° during late stance and swing phase as compared with healthy subjects (P < 0.05). Shank-foot continuous relative phase of patients is significantly decreased by 6.89° during early stance and significantly increased by 5.49° and 6.39° during late stance and swing phase (P < 0.05). Patients also exhibit increased variability of thigh-shank continuous relative phase during late stance and swing phase by 1.90° and 1.65° respectively, and increased variability of shank-foot continuous relative phase during early stance and swing phase by 0.83° and 0.88° respectively as compared to healthy subjects (P < 0.05).

SIGNIFICANCE

Patients with knee osteoarthritis exhibit altered coordination patterns and increased coordination variability of thigh-shank and shank-foot. Knee dysfunction results in altered lower limbs coordination and unstable motor control during walking. Investigation of inter-segmental coordination could therefore provide insights into changes in neuromuscular control of gait in patients with knee osteoarthritis.