Background: So far, there is much less information about the effects of urinary incontinence on postural control. Therefore the aim of this study is to investigate the differences in postural control using linear and non-linear analyses of the center of pressure (COP) time-series in anteroposterior (AP) and mediolateral (ML) directions between females with and without stress urinary incontinence (SUI). Methods: This case-control study included 22 continent females and 22 SUI females. In this study, static postural control during four different postural tasks was evaluated using a force plate. All participants performed separate 60-sec standing trials with eyes open in the empty bladder and full bladder conditions. Mean, range, velocity, area circle of COP displacements, and approximate entropy (ApEn) of COP time-series were calculated from the 60-sec standing trials for all participants. The independent sample t-test was also used to compare COP variables between the two groups and paired sample t-test was used to assess changes between the full bladder and empty bladder conditions within each group. The effect size of Cohen\'s d was used to assess the magnitude of the differences between the two groups. Results: The findings revealed a significant group × task interaction for the mean of ML displacement and ApEn of COP. SUI females showed more AP displacement range in the full bladder (pvalue= 0.020, effect size=0.74) and a higher velocity (empty bladder: p=0.040, effect size=0.63) (full bladder: p=0.020, effect size=0.75) than the continent group. Generally, the SUI females had lower ApEn than the continent females, although the differences were not significant. While the variables of COP were unaffected by bladder fullness in the continent group, the SUI group in full bladder condition experienced more AP range (p=0.030), and area circle (p=0.007) of COP sway in quiet standing. Conclusion: These results provide more support for the hypothesis that postural control can be impaired following SUI, although future investigations on this topic are recommended.

OBJECTIVE: In patients with Wallenberg\'s syndrome who present with body lateropulsion (BL), whether the center of pressure (COP) position and velocity characterize postural dysregulation is unknown. We measured time-course changes in COP parameters in three BL patients.
METHODS: Three patients with acute Wallenberg\'s syndrome presented with BL. COP was measured for time-course changes during first standing and every week thereafter. COP positions, which indicate the deviation in the center of gravity, were calculated. COP velocities associated with dynamic movements of the center of gravity were analyzed separately for the BL and non-BL sides.
RESULTS: All patients showed that COP position shifted to the BL side in first standing and changed to the center over time. COP velocities to the BL side were fast in first standing. Two of the three patients had significantly faster COP velocities to the BL side than to the non-BL side (p < .05), and one did not. In all three cases, the faster COP velocities to the BL side decreased significantly after 2 weeks compared to the initial standing position (p < .001). The change seemed to be related to the time when independent walking became possible.
CONCLUSIONS: Fast COP velocity to the BL side might reflect postural dysregulation in patients with BL. These findings might be useful information for devising effective rehabilitation in patients with BL.

The important role of postural stability in exercise performance has been determined by several authors. Despite this, few studies have analyzed the relationship between respiratory muscles\' strength and postural stability in athletes. For this reason, the aim of this study was to investigate the relationship between postural stability and respiratory muscles\' function in male soccer players. A case-control study was conducted over twenty-eight healthy men (18 soccer players; 10 non-athletes). Inspiratory muscle strength (MIP) and respiratory resistance (MVV) were obtained through a digital spirometer. Stability variables were obtained in standing position on a stabilometric platform and in open and closed eyes conditions. The area and length of the center of pressures and displacements in the X and Y range were analyzed. Pearson\'s coefficient was used to measure the linear correlation between MIP, MVV and stabilometric variables. In the soccer players\' group, MIP and MIP % predictive were inversely correlated with length (r = -0.535 and r = -0.585; p < 0.05) and X range (r = -0.527 and r = -0.560; p < 0.05), whereas MVV was directly correlated with length (r = 0.606; p < 0.01) and Y range (r = 0.558; p < 0.05). Our results show that the greater the inspiratory muscle strength, the less displacement of the pressure center, while at higher respiratory rates there is greater displacement.

This study aimed to analyze neuromuscular and postural control in visually and nonvisually impaired judo athletes. Two judo athletes, one visually impaired and the other nonvisually impaired, participated in the study. The athletes presented similar demographic, anthropometric, and judo-technical characteristics. They performed maximal isometric handgrip strength (dominant and nondominant hand), vertical jumps (countermovement jump [CMJ] and squat jump [SJ]), and center of pressure assessment in three positions: neutral, anteroposterior, and judo combat base (Migi-shizentai). The main findings showed that the visually impaired athlete presented higher standing balance in the neutral and anteroposterior positions than non-visually impaired athlete (effect size [ES]>2.0). In the Migi-shizentai position, the disparity between both athletes was reduced, particularly in the displacement area (ES=0.52). The visually impaired athlete showed higher performance in the SJ but lesser performance in CMJ and handgrip strength tests than nonimpaired athlete (ES>2.0). We concluded that the postural stability was higher in the visually impaired athlete in the neutral and anteroposterior position, but similar to the nonvisually impaired athlete in Migi-shizentai position, possible due to the influence of judo practice. Moreover, the visually impaired athlete showed higher performance in the SJ than nonvisually impaired.

BACKGROUND: Altered postural control represents one of the most common motor consequences following a concussion and there is a paucity of data monitoring the recovery trajectory that identifies the persistent changes of postural control.
OBJECTIVE: To determine whether the recovery trajectory of postural control was consistent across different measures of postural stability and whether increased postural challenge (ie, sloped surface) revealed subtle postural impairments.
METHODS: A single-subject case study.
METHODS: Research laboratory.
METHODS: One concussed individual with a cohort of healthy controls (n = 10) used for comparison.
METHODS: Center of pressure variability (linear-SD and nonlinear-multiscale entropy) was used to index postural sway preinjury and at periodic intervals following the concussion.
RESULTS: The concussed individuals displayed reduced amounts of sway during the initial recovery phase that failed to returned to preinjury levels but reached the level of healthy controls at 1-month postinjury. The multiscale entropy analysis revealed increased center of pressure irregularity throughout recovery that persisted up to 1-month post injury.
CONCLUSIONS: The findings identified subtle, persistent postural control impairments revealed through the nonlinear analysis of center of pressure and supports the notion that the consequences of a concussion (ie, impaired postural control) need to be considered beyond the resolution of behavioral symptoms.

For stroke survivors, balance deficits that persist after the completion of the rehabilitation process lead to a significant risk of falls. We have recently developed a balance-assessment robot (BAR-TM) that enables assessment of balancing abilities during walking. The purpose of this study was to test feasibility of using the BAR-TM in an experimental perturbed-balance training program with a selected high-functioning stroke survivor.
A control and an individual with right-side chronic hemiparesis post-stroke were studied. The individual post-stroke underwent thirty sessions of balance-perturbed training that involved walking on an instrumented treadmill while the BAR-TM delivered random pushes to the participant\'s pelvis; these pushes were in various directions, at various speeds, and had various perturbation amplitudes. We assessed kinematics, kinetics, electromyography, and spatio-temporal responses to outward-directed perturbations of amplitude 60 N (before training) and 60 N and 90 N (after training) commencing on contact of either the nonparetic-left foot (LL-NP/L perturbation) or the paretic-right foot (RR-P/R perturbation) while the treadmill was running at a speed of 0.4 m/s.
Before training, the individual post-stroke primarily responded to LL-NP/L perturbations with an in-stance response on the non-paretic leg in a similar way to the control participant. After training, the individual post-stroke added adequate stepping by making a cross-step with the paretic leg that enabled successful rejection of the perturbation at lower and higher amplitudes. Before training, the individual post-stroke primarily responded to RR-P/R perturbations with fast cross-stepping using the left, non-paretic leg while in-stance response was entirely missing. After training, the stepping with the non-paretic leg was supplemented by partially recovered ability to exercise in-stance responses on the paretic leg and this enabled successful rejection of the perturbation at lower and higher amplitudes. The assessed kinematics, kinetics, electromyography, and spatio-temporal responses provided insight into the relative share of each balancing strategy that the selected individual post-stroke used to counteract LL-NP/L and RR-P/R perturbations before and after the training.
The main finding of this case-control study is that robot-based perturbed-balance training may be a feasible approach. It resulted in an improvement the selected post-stroke participant\'s ability to counteract outward-directed perturbations.
ClinicalTrials.gov Identifier: NCT03285919 - retrospectively registered.

BACKGROUND: Postural instability is an important pathomarker in children with cerebral palsy (CP), and is often implicated in gait disturbance.
OBJECTIVE: The purpose of this study was to investigate the therapeutic effects of long-term robotic hippotherapy (HPOT) on postural muscles size and static and dynamic postural stability in a child with CP.
METHODS: Ultrasonography was used to measure postural muscles size. We also evaluated the magnitude of the separation between the center of pressure (COP) and center of mass (COM) during quiet stance and gait initiation (GI) using an eight-camera motion capture system and two force plates. Robotic HPOT was provided as a 45-minute session once per week for 12 weeks.
RESULTS: As transverse abdominal (12%) and lumbar multifidus (60%) muscles size improved, normalized sway area (16%) during the quiet stance decreased. Similarly, the maximal resultant COP-COM distance (12.84%) during the initial phase of GI increased.
CONCLUSIONS: In a child with CP, robotic HPOT may be an important treatment for improving postural muscles size and postural stability in static and dynamic states.

People are required to adapt their basic walking pattern to turn and change directions safely for activities of daily living. This case study describes the changes in neuromuscular control among individuals with stroke on walking paths of different curvatures. Two men with hemiparetic stroke and one control subject walked along a straight, wide curved, and tight curved pathway while muscle activation of the medial and lateral gastrocnemius was recorded, along with the trajectory of the center of pressure (COP) during the single support phase. Balance, sensorimotor control, and functional ambulation were also evaluated. The subject with greater lower-limb sensorimotor impairment displayed a larger difference in the anterior-posterior COP displacement between limbs, which exacerbated as the path curvature increased. In addition, while the control subject demonstrated a lateral shift in the medial-lateral COP position, this person was unable to adapt the COP position on the nonparetic side. The second participant with a stroke demonstrated better balance and lateral shifting of the COP position. Modulation of the COP trajectory is required to safely perform curved walking. Further study is required to confirm the role of stroke-related gait deficits in the ability to adapt to curved walking.

Stress fractures after total knee arthroplasty (TKA) occur mainly in patients with considerable deformity of the knee. In addition, the majority of these fractures after TKA involve the hip joint. We present two cases of stress fractures of the first metatarsal after TKA in patients with severe varus deformity. Correction of leg alignment and pain reduction obtained by TKA lead to stress fracture of the bone. Gait analysis was carried out for both cases in order to clarify the gait characteristics of the stress fracture. As a result, side-to-side differences of the distance between first metatarsal and foot center of pressure in the coronal plane were observed using gait analysis in these patients. Fortunately, conservative treatment was successful for these patients. Stress fractures should be considered when a patient who had a considerable severe deformity of the knee preoperatively complains of foot pain on the affected side. Contrary to stress fractures at the hip joint, patients with the fracture of the first metatarsal can be treated without surgery.