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BACKGROUND: Gait asymmetry is often accompanied by the bilateral asymmetry of the lower limbs. The transcranial direct current stimulation (tDCS) technique is widely used in different populations and scenarios as a potential tool to improve lower limb postural control. However, whether cerebral cortex bilateral tDCS has an interventional effect on postural control as well as bilateral symmetry when crossing obstacles in healthy female remains unknown. METHODS: Twenty healthy females were recruited in this prospective study. Each participant walked and crossed a height-adjustable obstacle. Two-way repeated ANOVA was used to evaluate the effect of group (tDCS and sham-tDCS) and height (30%, 20%, and 10% leg length) on the spatiotemporal and maximum joint angle parameters for lower limb crossing obstacles. The Bonferroni post-hoc test and paired t-test were used to determine the significance of the interaction effect or main effect. The statistically significant differences were set at p < 0.05. RESULTS: The Swing time (SW) gait asymmetry (GA), Stance time (ST) GA, leading limb hip-knee-ankle maximum joint angles and trailing limb hip-knee maximum joint angles decreased in the tDCS condition compared to the sham-tDCS condition at 30%, 20% leg's length crossing height except for 10% leg's length, whereas there was a significant decrease in SW/ST GA between the tDCS condition and the sham-tDCS condition at 30%, 20%, 10% leg's length crossing height (P < 0.05). CONCLUSION: We conclude that tDCS intervention is effective to reduce bilateral asymmetry in spatio-temporal parameters and enhance dynamic balance in female participants during obstacle crossing when the heights of the obstacles were above 10% of the leg's length. TRIAL REGISTRATION NO: ChiCTR2100053942 (date of registration on December 04, 2021). Prospectively registered in the Chinese Clinical Trial Registry.

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Maintaining sufficient muscle strength is fundamental to prevent a decline in basic physical functions such as gait, and is therefore a prerequisite for a healthy independent life in older people. However, the relationship between gait parameters and the strength of single muscle groups is reported with inconclusive results. The objective of this study was to analyze the relationship of strength of nine single muscle groups of lower and upper leg muscles as well as handgrip strength for gait parameters in older adults. Sixty-nine independently living older adults participated in the study. Maximum ankle plantar- and dorsiflexion, knee flexion and extension, as well as hip abduction, adduction, flexion, and extension strength, were measured using an isokinetic dynamometer. Additionally, hand grip strength measured via a hand dynamometer was obtained. Walking gait parameters were recorded with a 3D motion capture system on an instrumented treadmill. The relationships between multiple strength and gait variables were analyzed by Pearson's correlation coefficient. Linear regression analyses were performed to identify the predictive ability of muscle strength (normalized to body weight) for gait speed, stride time, stance time, stride length and step width. Multiple significant weak to moderate positive ([r = 0.343, p = 0.047]-[r = 0.538, p = 0.002]) and negative ([r = -0.340, p = 0.046]-[r = 0.593, p = 0.001]) correlations that were unequally distributed between both sexes were detected. Significant regression models explained ([r2 = 16.6%, p = 0.015]-[r2 = 44.3 %, p = 0.003]) and ([r2 = 21.8%, p = 0.022]-[r2 = 36.1%, p = 0.044]) of the gait parameter variations for men and women, respectively. The results suggest a sex-specific relevance of single muscle groups for all gait parameters. This may be attributed to anatomical differences and it is important to prevent strength-related changes in gait parameters.

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Force plate analysis assesses gait symmetry and limb loading. However, as previously described, individual and breed variability (body size and conformation) is related to breeding, body conformation, and size. This prospective study aimed to evaluate the influence of morphometric measures on the speed (V), peak of vertical force (PVF), vertical impulse (VI), and stance time (ST) in healthy dolichomorph and mesomorph dogs and their combined effect on and interactions with V, PVF, VI, and ST in the same morphological types. Fifty dogs were enrolled in the current study, and specific morphometric measurements were recorded for each dog. A force platform was used to record the ground reaction forces (GFRs), including PVF and VI. Multiple linear regression models were used for the study purposes. According to our results, GFRs are influenced by morphometric measures (body weight, withers height, and speed) not so much as a single contribution, but by the interaction between them. It is not possible to compare GFRs in dogs that do not belong to the same breed. However, the subjective variabilities make this comparison difficult and poorly reliable. According to the author, the comparison should be made between canine morphological types rather than breeds.

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Instrumented earbuds equipped with accelerometers were developed in response to limitations of currently used running wearables regarding sensor location and feedback delivery. The aim of this study was to assess test-retest reliability, face validity and concurrent validity for cadence and stance time in running. Participants wore an instrumented earbud (new method) while running on a treadmill with embedded force-plates (well-established method). They ran at a range of running speeds and performed several instructed head movements while running at a comfortable speed. Cadence and stance time were derived from raw earbud and force-plate data and compared within and between both methods using t-tests, ICC and Bland-Altman analysis. Test-retest reliability was good-to-excellent for both methods. Face validity was demonstrated for both methods, with cadence and stance time varying with speed in to-be-expected directions. Between-methods agreement for cadence was excellent for all speeds and instructed head movements. For stance time, agreement was good-to-excellent for all conditions, except while running at 13 km/h and shaking the head. Overall, the measurement of cadence and stance time using an accelerometer embedded in a wireless earbud showed good test-retest reliability, face validity and concurrent validity, indicating that instrumented earbuds may provide a promising alternative to currently used wearable systems.

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Prior researchers have observed the effect of simulated reduced-gravity exercise. However, the extent to which lower-body positive-pressure treadmill (LBPPT) walking alters kinematic gait characteristics is not well understood. The purpose of the study was to investigate the effect of LBPPT walking on selected gait parameters in simulated reduced-gravity conditions. Twenty-nine college-aged volunteers participated in this cross-sectional study. Participants wore pressure-measuring insoles (Medilogic GmBH, Schönefeld, Germany) and completed three 3.5-min walking trials on the LBPPT (AlterG, Inc., Fremont, CA, USA) at 100% (normal gravity) as well as reduced-gravity conditions of 40% and 20% body weight (BW). The resulting insole data were analyzed to calculate center of pressure (COP) variables: COP path length and width and stance time. The results showed that 100% BW condition was significantly different from both the 40% and 20% BW conditions, p < 0.05. There were no significant differences observed between the 40% and 20% BW conditions for COP path length and width. Conversely, stance time significantly differed between the 40% and 20% BW conditions. The findings of this study may prove beneficial for clinicians as they develop rehabilitation strategies to effectively unload the individual's body weight to perform safe exercises.

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OBJECTIVES: To determine the most important motor impairments that are predictors of gait velocity and spatiotemporal symmetrical ratio in patients with stroke. DESIGN: Cross-sectional, descriptive analysis study. SETTING: Human performance laboratory of the University of Santo Tomas. PARTICIPANTS: Individuals with chronic stroke (N=55; 34 men, 21 women) who are community dwellers. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The gait velocity and spatiotemporal symmetrical ratio (step length; step, stance, swing, single-leg support, and double-leg support stance times) was determined using Vicon motion capture. We also calculated motor impairment of the leg and foot using Brunnstrom's stages of motor recovery, evaluated muscle strength using the scoring system described by Collin and Wade, and assessed spasticity using by the modified Ashworth Scale. RESULTS: Regression analysis showed that plantarflexor strength is a predictor of gait velocity and all temporospatial symmetry ratio. Knee flexor and extensor strength are predictors in single-leg support time and double-leg support time symmetry ratio, respectively. On the other hand, hip adductor and quadriceps spasticity are predictors of swing time and step length symmetry ratio. CONCLUSION: Different motor impairments are predictors of stroke gait abnormality. Interventions should be focused on these motor impairments to allow for optimal gait rehabilitation results.

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The World Health Organization has recommended 5 g/day as dietary reference intakes for salt. In Japan, the averages for men and women were 11.0 g/day and 9.3 g/day, respectively. Recently, it was reported that amounts of sodium accumulation in skeletal muscles of older people were significantly higher than those in younger people. The purpose of this study was to investigate whether the risk of sarcopenia with decreased muscle mass and strength was related to the amount of salt intake. In addition, we investigated its involvement with renalase. Four groups based on age and salt intake ("younger low-salt," "younger high-salt," "older low-salt," and "older high-salt") were compared. Stratifying by age category, body fat percentage significantly increased in high-salt groups in both younger and older people. Handgrip strength/body weight and chair rise tests of the older high-salt group showed significant reduction compared to the older low-salt group. However, there was no significant difference in renalase concentrations in plasma. The results suggest that high-salt intake may lead to fat accumulation and muscle weakness associated with sarcopenia. Therefore, efforts to reduce salt intake may prevent sarcopenia.

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[Purpose] This study aimed to examine the impact of changing the drop vertical jump stance time on kinematic and kinetic parameters by ordering to high jump or quick jump for consistent stance time and a more accurate assessment of anterior cruciate ligament injury risk. [Participants and Methods] The participants were 20 healthy female students. The drop vertical jump was started by instructing the participants to stand on a 30-cm platform with both legs stationary. The task was performed while the participants were instructed to perform high jump or quick jump. [Results] Stance time was significantly shorter with quick jump than with high jump. Quick jump showed significantly higher knee abduction angles at initial contact and peak vertical ground reaction force, and lower hip flexion, knee flexion, and ankle dorsiflexion angles at the lowest point of the center of mass. Quick jump showed a significantly higher peak vertical ground reaction force. The knee abduction moment at initial contact was not significantly different between the 2 conditions. [Conclusion] Quick jump was better than high jump for making stance time consistent, and the differences in kinematic and kinetic characteristics by oral instructions should be considered when using drop vertical jump.

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INTRODUCTION: Pressure-measuring insoles can provide a portable alternative to existing gait analysis tools. However, there is disagreement among researchers on their accuracy and the appropriate calibration methods. The purposes of this study were to (1) determine the validity of pressure-measuring insoles for calculating stance time and support-phase impulse during walking using two calibration procedures, and (2) examine the effect of insole size on the results. METHODS: Data were collected from 39 participants (23.5 ± 3.24 yrs, 66.7 ± 17.5 kg, 1.64 ± 0.09 m), each wearing appropriately sized insoles as they walked over two consecutive force platforms. Two calibration methods were evaluated: (1) manufacturer's recommendation, and (2) a participant weight-based approach. Qualitative and quantitative evaluations were conducted. RESULTS: The results indicated that the insoles measured longer stance times than the force platform (differences are less than 10%). Both calibration methods resulted in inaccurate impulse values (differences are 30 and 50% for the two calibration methods, respectively). The results showed that when using the first calibration method, impulse values depended on insole size. The second calibration consistently underestimated the impulse. CONCLUSIONS: It was concluded that while the insoles provide acceptable qualitative representation of the gait, the two studied calibration methods may lead to a misleading quantitative assessment.

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Inertial measurement units (IMUs) have been extensively used to detect gait events. Various methods have been proposed for detecting initial contact (IC) and toe-off (TO) using IMUs affixed at various anatomical locations. However, the accuracy of such methods has yet to be compared. This study evaluated the accuracy of three common methods used for detecting gait events during jogging and running: (1) S-method, in which IC is identified as the instant of peak foot-resultant acceleration and TO is identified when the acceleration exceeds a threshold of 2g in the region of interest; (2) M-method, in which IC and TO are defined as the minimum before the positive peak shank vertical acceleration and the minimum in the region of interest, respectively; and (3) L-method, in which IC is indicated by the instant of peak pelvis anteroposterior acceleration and TO is identified by the maximum in the region of interest. The performance of the IMU-based methods in detecting IC and TO and estimating stance time (ST) were tested on 11 participants at jogging and running speeds against a reference provided by a force-platform method. The S-method was the most accurate for IC detection (overall mean absolute difference (MAD): 4.7±4.1ms). The M-method was the most accurate for TO detection (overall MAD: 7.0±3.5ms). A combination of M- and S-methods, called the MS-method, was the most accurate for ST estimation (overall MAD: 9.0±3.9ms). Thus, the MS-method is recommended for ST estimation; however, this method requires four IMUs for bilateral estimation.

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Poor traction on slick surfaces is difficult for dogs with neurologic deficits, osteoarthritis, or recovering from injury or surgery. Many dogs respond inappropriately to slick surfaces by decreasing digital pad-floor contact and extending their toenails. A device marketed to increase paw-floor friction in dogs was evaluated. Fifteen normal dogs underwent kinetic gait analysis before and after application of Dr. Buzby's ToeGrips®. Ground reaction forces, including vertical peak force (VPF) and impulse for each limb, were measured and compared between pre- and post-application values. Stance time was significantly increased in all limbs after toe grip application. Stride velocity was slower in all limbs but significantly slower only in the left forelimb. VPF was significantly deceased in both hindlimbs after toe grip application, but the decrease was within the group SDs. Vertical impulse was significantly increased in both forelimbs and in the right hindlimb. Dr. Buzby's ToeGrips® result in a slower gait, with slightly decreased VPF in the hindlimbs and increased effort for propulsion kinetic changes were of minor magnitude and unlikely to be clinically relevant.

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The purpose of this study was to investigate the effect of load carriage on the kinematics and kinetics of the ankle and knee joints during uphill walking, including joint work, range of motion (ROM), and stance time. Fourteen males walked at a self-selected speed on an uphill (15°) slope wearing military boots and carrying a rifle in hand without a backpack (control condition) and with a backpack. The results showed that the stance time significantly decreased with backpack carriage (p < .05). The mediolateral impulse significantly increased with backpack carriage (p < .05). In the ankle joints, the inversion-eversion, and dorsi-plantar flexion ROM in the ankle joints increased with backpack carriage (p < .05). The greater dorsi-plantar flexion ROM with backpack carriage suggested 1 strategy for obtaining high plantar flexor power during uphill walking. The result of the increased mediolateral impulse and inversion-eversion ROM in the ankle joints indicated an increase in body instability caused by an elevated center of mass with backpack carriage during uphill walking. The decreased stance time indicated that an increase in walking speed could be a compensatory mechanism for reducing the instability of the body during uphill walking while carrying a heavy backpack.

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BACKGROUND AND OBJECTIVE: The purpose of this study was to find "Effect of lower extremity stretching exercises on balance in the geriatric population. METHOD: 60 subjects (30 male and 30 female) participated in the study. The subjects underwent 10 weeks of lower limb stretching exercise program. Pre and post 10 weeks stretching exercise program, the subjects were assessed for balance, using single limb stance time in seconds and berg balance score. These outcome measures were analyzed. RESULTS: Pre and post lower extremity stretching on balance was analyzed using paired t test. Of 60 subjects 50 subjects completed the stretching exercise program. Paired sample t test analysis showed a significant improvement in single limb stance time (eyes open and eyes closed) (p<0.001) and berg balance score (p<0.001). CONCLUSION: Lower extremity stretching exercises enhances balance in the geriatric population and thereby reduction in the number of falls.

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This study quantified how body borne load impacts hip and knee biomechanics during anticipated and unanticipated single-leg cutting maneuvers. Fifteen male military personnel performed a series of single-leg cutting maneuvers with three different load configurations (light, ~6 kg, medium, ~20 kg, and heavy, ~40 kg). Subject-based means of the specific lower limb biomechanical variables were submitted to repeated measures ANOVA to test the main and interaction effects of body borne load and movement type. With body borne load, stance time (P<0.001) increased, while larger hip (P=0.027) and knee flexion (P=0.004), and hip adduction (P<0.001) moments, and decreased hip (P=0.002) and knee flexion (P<0.001), and hip adduction (P=0.003) postures were evident. Further, the hip (P<0.001) and ankle (P=0.024) increased energy absorption, while the knee (P=0.020) increased energy generation with body borne load. During the unanticipated maneuvers, the hip (P=0.009) and knee (P=0.032) increased energy generation, and peak hip flexion moment (P=0.002) increased relative to the anticipated movements. With the body borne load, participants adopted biomechanical patterns that decreased their locomotive ability including larger moments and reduced flexion postures of the lower limb. During the single-leg cut, participants used greater energy absorption from the large, proximal muscles of the hip and greater energy generation from the knee with the addition of load. Participant's performance when carrying a range of loads was not compromised by anticipation, as they did not exhibit the hip and knee kinetic and kinematic adaptations previously demonstrated when reacting to an unplanned stimulus.

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