Impact of lower muscle stiffness on ankle dorsiflexion restriction in children with cerebral palsy evaluated using ultrasound elastography.

BACKGROUND: Plantar flexor muscles always contribute to limiting the range of motion of ankle dorsiflexion in children with spastic cerebral palsy, but the individual contributions of these muscles are not well defined. This study aimed to identify which muscles' stiffness impacts the dorsiflexion range of motion in children with cerebral palsy. METHODS: Twenty-five children with cerebral palsy were included. The maximum passive dorsiflexion range of motion was measured in two positions: hip and knee joints in flexion, and both joints in full extension. Strain ratios indicating muscle stiffness were measured using strain elastography of the lateral and medial gastrocnemius, soleus, flexor hallucis longus, peroneus longus, peroneus brevis, and tibialis posterior muscles. To analyze which muscles impact the limitation of the dorsiflexion range, multiple regression analyses were conducted. The values of muscle stiffness were included as independent valuables, and the values of the dorsiflexion range were included as dependent valuables. A p-value <0.05 was considered statistically significant. FINDINGS: In the analyses, the soleus and flexor hallucis longus muscle stiffness were significant independent factors for the dorsiflexion range of motion of hip and knee flexion (adjusted R2: 0.50). The lateral gastrocnemius muscle stiffness was a significant independent factor for the dorsiflexion range of motion with both joints in full extension (adjusted R2: 0.61). INTERPRETATION: Flexor hallucis longus muscle stiffness, in addition to triceps surae muscle stiffness, was shown to impact dorsiflexion range; attention should be paid to muscle stiffness in children with cerebral palsy.

Gait velocity control using projection mapping for children with spastic diplegia cerebral palsy.

BACKGROUND: Gait characteristics in children with cerebral palsy vary according to their individual walking speed. As such, establishing methods to maintain a consistent gait velocity are necessary to evaluate specific intervention effects in this clinical population. Our study aim was to validate the accuracy of projection mapping for guiding gait velocity to a control gait velocity. METHODS: This was a cross-sectional study of 13 children with cerebral palsy (mean age [standard deviation] of 12.42 [2.31] years). The target velocity was calculated from the average speed obtained across three trials of self-selected walking speed. A virtual reality system with four projectors was used to project an image onto the floor to guide children to match two gait conditions: 100% and 125% velocity of the average speed. Participants completed three gait trials at each velocity under image guidance. Gait velocity was quantified using a 3-dimensional motion capture system. Bland-Altman plots were used to analyze systematic errors and the limits of agreement calculated. FINDINGS: The results indicated the limits of agreement were acceptable for 0.10 m/s for 100% velocity and 0.12 m/s for 125% velocity. Therefore, projection mapping was effective in guiding children to adjust their gait to the intended velocity. INTERPRETATION: Projection mapping is a novel method for guiding children with cerebral palsy to walk at a controlled target velocity that may improve the reliability of gait analysis.

Relationship between the knee valgus moment and the hip abductor and adductor activity during single-leg landing.

OBJECTIVES: To reveal the relationship between the knee valgus moment (KVM) and the hip abductor and adductor activity during single-leg landing. DESIGN: A cross-sectional study. SETTING: Laboratory-based, between April 2020 and May 2021. PARTICIPANTS: Thirty female collegiate athletes. MAIN OUTCOME MEASURES: KVM, hip adduction angle, hip internal rotation angle, knee valgus angle (KVA), gluteus medius muscle activity, adductor longus muscle activity, adductor longus to gluteus medius activity ratio (ADD/GMED), and vertical component of the ground reaction force (vGRF). RESULTS: Stepwise multiple regression analysis was performed. KVM was significantly positively associated with KVA (ß = 0.613, p < 0.001), vGRF (ß = 0.367, p = 0.010), and ADD/GMED (ß = 0.289, p = 0.038). CONCLUSIONS: Increased KVA, vGRF, and ADD/GMED were the independent factors that contributed to increased KVM during single-leg landing, and only ADD/GMED was found among the muscle activity values. The relative muscle activity of the gluteus medius and adductor longus, rather than those of the gluteus medius or adductor longus alone, may be useful in preventing anterior cruciate ligament injury during single-leg landing.

Foot pressure-based analysis of gait while using a smartphone.

BACKGROUND: The number of incidents related to walking while using smartphones is rising. However, it is not clear how smartphone usage might affect a gait pattern in terms of the foot pressure, and this may address the mechanism leading to incidents while using smartphones. RESEARCH QUESTION: How do the characteristics of walking while using a smartphone affect foot pressure patterns? METHODS: In this cross-sectional study, we recruited 40 healthy young participants and investigated the walking speed, step length, coefficient of variance of the walking cycle (CV), anteroposterior length of the center of pressure (COP) trajectory (%Long), partial foot pressure ratios (% partial foot pressure [%PFP]), and COP existence time (COPexT) under the following four conditions: normal walking, screen gazing, while using social networking services (SNS), and while using a cognitive application. Parameters were compared among the four conditions using a repeated-measures ANOVA. Further, according to the presence or absence of an incident history (e.g. stumbles, collisions), participants were divided into either the incident or non-incident group. Parameters were compared between the two groups using a two-way repeated-measures ANOVA. RESULTS: Under the SNS and cognitive application conditions, the walking speed, step length, %Long, %PFP, and COPexT in the heel were significantly lower, and the CV and %PFP in the metatarsal region were higher than those under normal walking or screen gazing. %PFP in the heel and metatarsal regions showed a significant group-by-condition interaction; the incident group had lower %PFP in the heel region and higher %PFP in the metatarsal region than the non-incident group. SIGNIFICANCE: These findings indicate a trend of loading more pressure on the forefoot than on the heel. This pattern was markedly evident in individuals with a history of incidents related to the smartphone usage and may be one of the factors causing stumbles and collisions.

Gait-related self-efficacy is directly associated with daily step counts in individuals with knee osteoarthritis.

BACKGROUND: In addition to physical factors, psychological factors such as self-efficacy (SE) reportedly affect physical activity (PA) levels in individuals with knee osteoarthritis (OA). However, the relationship between PA and SE for walking tasks in patients with knee OA remains unclear. The present study aimed to investigate the direct and indirect pathways of SE for walking tasks and the influence of previously reported factors on PA level in individuals with knee OA. METHODS: A cross-sectional design was employed. Eighty-five individuals with knee OA were enrolled. The daily step count (Steps) was considered an objective level of PA. The SE for the walking task was assessed using a modified Gait Efficacy Scale (mGES). Data on gait speed (GS), the visual analog scale (VAS) score for knee pain, Kellgren-Lawrence (K-L) grade of radiographic severity of knee OA, age, and body mass index were collected. Path analysis was performed to investigate the direct and indirect effects of these variables on Steps. RESULTS: After exclusion, 70 participants were included. The alternative model, which included Steps, mGES, GS, VAS, K-L grade, and age, showed a good fit. mGES and age had a direct effect on Steps (standardized path coefficients: 0.337 and -0.542, respectively), while the other variables had indirect effects. CONCLUSIONS: The SE for walking tasks was directly associated with Steps representative of the PA level. This finding suggests that SE for the walking task may be important in improving PA levels in individuals with knee OA.

Assessment of central aponeurosis curvature as an index of rectus femoris muscle overstrain in individuals with knee osteoarthritis.

BACKGROUND: In medial knee osteoarthritis (knee OA), compensatory overstrain of the rectus femoris (RF) muscle leads to its hypertrophy. We hypothesize that besides hypertrophy of the RF, a prominent flattening of the central aponeurosis (CA) curvature is also indicative of RF. This study aims to evaluate the structural changes in the CA and clarify the conditions associated with RF overstrain in knee OA. OBJECTIVE: Twenty-three legs of 20 elderly without knee OA (elderly group) and 26 legs of 20 individuals with K-L grade II knee OA (knee OA group) with typical "comma"-shaped CA participated in this study. METHODS: The knee extension torque (Nm/kg) in the sitting position, the thickness of the RF and vastus intermedius (VI) muscles (VI), and change in CA curvature (%Curvature) were measured at the mid-thigh by ultrasonography. RESULTS: The knee extension torque was not significantly different between the two groups. Compared to the elderly group, the knee OA group had significantly thicker RF at rest, while the VI thickness during contraction was significantly smaller. The %Curvature was significantly higher in the knee OA group than in the elderly group. CONCLUSIONS: In the knee OA group, the RF was hypertrophic with a more pronounced CA flattening during muscle contraction, although the other quadriceps muscles were atrophic, suggesting an overstrained RF. Assessing thickness and CA curvature of the RF is, therefore, useful and simple for evaluating overstrain caused by RF compensation.

Changes to foot pressure pattern in post-stroke individuals who have started to walk independently during the convalescent phase.

BACKGROUND: Abnormal foot contact patterns following stroke affect functional gait; however, objective analysis targeting independent walking is lacking. RESEARCH QUESTION: How do walking abilities and foot pressure patterns differ between post-stroke individuals who achieved independent walking and healthy controls? Secondarily, how do the abilities and patterns in post-stroke individuals change before and after achieving independent walking? Can these changes become criteria for permitting independent walking? METHODS: Twenty-eight individuals with hemiplegia and 32 controls were enrolled. Motor dysfunction score (MDScore), walking speed (WSpeed), and foot pressure patterns were measured when they were first able to walk without orthosis or physical assistance (1st assessment) and when they achieved independent walking around discharge (2nd assessment). Foot pressure patterns were measured using insole-type foot pressure-measuring system. Ratios of partial foot pressure to body weight (%PFP), ratios of anteroposterior length of center of pressure (COP; %Long), and backward moving distance of COP to the foot length (%Backward) were calculated. Parameters during the 2nd assessment were compared with those of controls and those during the 1st assessment. During the 2nd assessment, relationships among the parameters, MDScore, and WSpeed were analyzed. RESULTS: During the 2nd assessment, no difference was observed in both %Long and %Backward between the non-paretic limbs and the controls. While the %Backward was higher, the %PFP of toes and %Long were lower in the paretic limb than in the controls. Although the %Backward was lower, both %PFP of toes and %Long of the paretic limb were higher in the 2nd assessment than in the 1st assessment. During the 2nd assessment, both %Long and % Backward values of the paretic limb moderately correlated with MDScore and WSpeed. SIGNIFICANCE: After improvement of foot pressure in toes, both an increase in anteroposterior length and a decrease in backward moving of COP path were objective signs permitting independent walking.

Hyperechoic and Low Morphological Changes in the Prefemoral Fat Pad in Individuals with Knee Osteoarthritis Based on Ultrasonographic Findings.

BACKGROUND: To clarify the changes in the echo intensity (EI) in the prefemoral fat pad (PFP) and identify the relationship between the PFP and clinical features of knee osteoarthritis (OA). METHODS: Twenty-six women with knee OA (mean age: 76 years) and 17 healthy women (mean age: 73 years) were enrolled. The Kellgren and Lawrence grading scale was used for the radiographic evaluation of knee OA. The EI of the PFP was measured as grayscale values. The change ratio of the anteroposterior PFP length during quadriceps contraction was measured. Knee range of motion and pain (100-mm visual analog scale) were evaluated. RESULTS: The EI was significantly higher in the OA group than in the healthy group (P < 0.001). The change ratio of the PFP in the OA group was significantly lower than that in the healthy group (P < 0.001). The ranges of knee flexion and extension were correlated with the EI of the PFP (both P < 0.01) and the change ratio of the PFP (both P < 0.01). There was no significant correlation observed with knee pain. CONCLUSION: Hyperechoic changes and a decreased change ratio of the PFP were observed in the patients with knee OA. High EI and decreased morphological PFP changes were associated with decreased ranges of motion.

Analysis of center of mass and center of pressure displacement in the transverse plane during gait termination in children with cerebral palsy.

BACKGROUND: While gait termination is challenging for children with spastic cerebral palsy (CCP), few studies have quantitatively assessed this issue. RESEARCH QUESTION: What are the characteristics of center of mass (COM) and center of pressure (COP) displacement during gait termination in CCP, and how do they compare with those in children with typical development (CTD)? METHODS: This cross-sectional study included 13 adults with typical development (19.85 ± 0.52 years), 12 CTD (10.41 ± 2.98 years), and 16 CCP (11.15 ± 2.71 years). Participants were instructed to immediately stop walking when a stop sign appeared on a screen, which was placed at the end of an 8-m walkway. COM and COP were determined via 3-dimensional motion analysis and force plate data. Differences between the groups were assessed using the two sample t-test or Wilcoxon rank sum test. The level of statistical significance was set at P < 0.05. RESULTS: The normalized time for stopping in CCP (4.556 ± 0.602) was higher than that in CTD (3.617 ± 0.545, P < 0.001). The normalized COP displacement (P < 0.001) and divergence between COM and COP (P < 0.001) in the mediolateral (ML) direction were significantly higher in CCP than CTD. However, the normalized divergence between COM and COP in the anteroposterior (AP) direction in CCP was lower than that in CTD (P = 0.034). SIGNIFICANCE: The more minor divergence between COM and COP in the AP direction and the more significant COP displacement in the ML direction cause difficulty to exert braking force during gait termination. Thus, CCP require a longer time for gait termination. This finding may facilitate the development of interventions for improving gait in CCP.

Effect of heel lifts in elderly individuals with spinal kyphosis.

BACKGROUND: The present study aimed to elucidate the effects of heel lifts on spinal alignment, walking, and foot pressure pattern in elderly individuals with spinal kyphosis. METHODS: The spinal alignment, walking speed, step length and foot pressure of 33 community-dwelling elderly individuals with spinal kyphosis (3 men, 30 women; mean age 77.3 years) were examined before and after the application of 10-mm moderately elastic heel lifts. FINDINGS: Spinal alignment of total inclination (mean value 6.9°vs 4.5°) and thoracic angle (43.6°vs 36.2°) were significantly lower after the application of heel lifts than before the application. The lumbar angle (7.3°vs 10.0°) was significantly higher after the application than before the application. Walking speed (0.78 vs 0.88 m/s) and step length (0.42 m vs 0.45 m) were significantly higher after the application. The partial foot pressure as a percentage of body weight of the hallux (6.7% vs 9.0%) and lateral toes (6.5% vs 9.0%) was significantly higher after the application of heel lifts than before the application. The partial foot pressure as a percentage of body weight of the heel (68.9% vs 57.5%) was significantly lower after the application than before the application. INTERPRETATION: In conclusion, heel lifts influenced the sagittal spinal alignment of elderly individuals. Walking speed and step length increased after the application of these devices. Increase in foot pressure in the hallux and lateral toe areas was probably related to these improvements in walking parameters.

Alignment of the rearfoot and foot pressure patterns of individuals with medial tibial stress syndrome: A cross-sectional study.

OBJECTIVE: To compare the rearfoot alignment (leg-heel angle, LHA) during standing and walking, and foot pressure during walking between individuals with medial tibial stress syndrome (MTSS) and asymptomatic individuals participating in daily sports. DESIGN: A cross-sectional study. SETTING: Research laboratory. PARTICIPANTS: MTSS (18 legs) and control (15 legs) participants. MAIN OUTCOME MEASURES: The LHA in the frontal plane during walking and standing; partial foot pressures expressed as the percentage of body weight (%PFP); and transverse width of the center of pressure (COP) path expressed as the percentage of foot width (%Trans) on walking. RESULTS: The LHA while walking was significantly higher in MTSS individuals, whereas the LHA while standing was not significantly different. The %PFPs of medial metatarsal areas were significantly higher in MTSS patients, whereas the %Trans was significantly lower. CONCLUSIONS: In individuals with MTSS, the LHA is similar to controls while standing but higher (more everted) while walking while there is higher pressure under the medial metatarsal areas and the COP is more medial. Rearfoot malalignment in individuals with mild to moderate MTSS can be detected on walking, even if the alignment on standing is normal.

In Vivo Flattening of the Central Aponeurosis of the Rectus Femoris Due to Knee Extension Torque in Healthy Young and Elderly Individuals With Knee Osteoarthritis.

ABSTRACT: We aimed to elucidate the relationship between active force production and the curvature of the central aponeurosis (CA) of the rectus femoris in young healthy participants as fundamental data and compare the muscle CA curvature before and after straight leg raising (SLR) training in participants with knee osteoarthritis (OA). Central aponeurosis curvature was determined during submaximal and maximal voluntary contractions (MVCs) using ultrasonography. Twenty-five young healthy female volunteers underwent ultrasonographic measurements under conditions of isometric MVC. They were divided into a flat shaped CA group (flat) and an incompletely flat shaped CA group (remnant). Central aponeurosis curvature was calculated as the ratio of CA height and length in the axial view. Central aponeurosis shape and muscular strength before and after muscle training were measured in 11 participants with knee OA. In the young healthy individuals, maximal voluntary torque and changes in CA curvature were significantly higher in the flat group than in the remnant group (2.15 Nm/kg and - 17.7% vs 1.75 Nm/kg and -9.8%, respectively; P = 0.005). The rate of change of the CA curvature during contraction was significantly correlated with maximal voluntary torque corrected for body mass (r = 0.512). The CA curvature progressively decreased as %MVC increased. In the OA group, CA curvature during MVC after SLR training was significantly lower than that before SLR training (3.2% vs 7.2%; P = 0.031). Central aponeurosis curvature was associated with muscle strength, and the results supported our hypothesis that geometric observation of CA changes during contractions may reflect muscle fiber function. We aim to develop a new ultrasonographic skeletal muscle evaluation method based on our present findings.

Relationship between walking efficiency and muscular strength of the lower limbs in children with cerebral palsy.

[Purpose] In children with cerebral palsy, despite increases in muscle strength after strengthening, improvements in walking efficiency are inconsistent in previous studies. The purpose of this study was to analyze the relationship between walking efficiency and muscle strength in children with cerebral palsy. [Participants and Methods] Twenty-six children with cerebral palsy participated in this study. Isometric muscle strength in the lower extremities and the Total Heart Beat Index were measured. Participants were divided into the high and low walking efficiency groups based on the median Total Heart Beat Index value (2.06 beats/m). [Results] For all participants, all isometric muscle strength values were significantly correlated with the Total Heart Beat Index. In the high walking efficiency group, there was no significant correlation. All isometric muscle strength values in the low walking efficiency group were significantly correlated with the Total Heart Beat Index, except for that of the hip extensors. [Conclusion] The influence of muscular strength on walking efficiency in children with cerebral palsy varied. Significant correlations were observed only for those in the low walking efficiency group. The walking efficiency level should be confirmed before planning muscle strength training to improve walking efficiency.

Age-related changes in muscle elasticity and thickness of the lower extremities are associated with physical functions among community-dwelling older women.

AIM: To clarify the age-related changes in muscle elasticity or thickness of the lower extremities in older women, and to analyze their relationship with physical functions. METHODS: The muscle elasticity and thickness of the rectus femoris and medial head of the gastrocnemius of 102 young women (young group) and 221 elderly women (elderly group) were measured using ultrasonography. In the elderly group, physical functions, including knee extension strength, Timed Up and Go test, single-leg standing, maximum gait speed and Four Square Step Test were also measured. RESULTS: The elasticity of the rectus femoris and medial head of the gastrocnemius were significantly higher, but the muscle thickness of both muscles was significantly lower in the elderly group than in the young group (both P < 0.001). In the elderly group, the elasticity of the rectus femoris was significantly correlated with Timed Up and Go test, maximum gait speed and Four Square Step Test (ρ = 0.481, r = -0.387 and ρ = 0.401, respectively, all P < 0.001), and the medial head of the gastrocnemius was similar (ρ = 0.471, r = -0.489 and ρ = 0.422, respectively, all P < 0.001). The muscle thickness of the rectus femoris was significantly associated with knee extension strength (r = 0.444, P < 0.001). CONCLUSIONS: Older women showed age-related changes in high elasticity and atrophy of the rectus femoris and medial head of the gastrocnemius. The high elasticity of both muscles, not muscle thickness, was associated with dynamic balance and walking ability. Geriatr Gerontol Int 2019; 19: 61-65.

The association between the maximum step length test and the walking efficiency in children with cerebral palsy.

[Purpose] To improve walking efficiency could be useful for reducing fatigue and extending possible period of walking in children with cerebral palsy (CP). For this purpose, current study compared conventional parameters of gross motor performance, step length, and cadence in the evaluation of walking efficiency in children with CP. [Subjects and Methods] Thirty-one children with CP (21 boys, 10 girls; mean age, 12.3 ± 2.7 years) participated. Parameters of gross motor performance, including the maximum step length (MSL), maximum side step length, step number, lateral step up number, and single leg standing time, were measured in both dominant and non-dominant sides. Spatio-temporal parameters of walking, including speed, step length, and cadence, were calculated. Total heart beat index (THBI), a parameter of walking efficiency, was also calculated from heartbeats and walking distance in 10 minutes of walking. To analyze the relationships between these parameters and the THBI, the coefficients of determination were calculated using stepwise analysis. [Results] The MSL of the dominant side best accounted for the THBI (R2=0.759). [Conclusion] The MSL of the dominant side was the best explanatory parameter for walking efficiency in children with CP.