The effect of different subtalar joint pronation amounts on postural stability, function and lower extremity alignment in healthy individuals.

INTRODUCTION: The prone foot posture has a negative effect on postural stability, function, and knee valgus, but to our knowledge, the contribution of the degree of pronation has not been examined. METHODS: 39 participants aged 18-40, with Foot Posture Index (FPI) scores between 6-12 and without any pain complaints were included. Participants with 6-9 points were included in the pronation group (PG) (n = 19), and participants with 10-12 points were included in the hyperpronation group (HPG) (n = 20). Static and dynamic postural stability, Foot and Ankle Ability Measure (FAAM), and frontal plane projection angles (FPPA) were measured for all participants. RESULTS: The initial data of the participants are distributed homogeneously. In the intergroup evaluation only FPI-1 (p = 0.001; p < 0.05), FPI-4 (p = 0.00; p < 0.05), FPI-5 (p = 0.00; p < 0.05) and FPI-T (p = 0.000; p < 0.05) scores were found significantly different. CONCLUSION: Pronation and hyperpronation of the subtalar joint did not lead to a difference in postural stability, function, and knee valgus in healthy individuals. It may be more beneficial to focus on the prone posture rather than the degree of pronation.

The effect of surface on knee landing mechanics and muscle activity during a single-leg landing task in recreationally active females.

OBJECTIVE: Investigate the effect of surface on frontal plane knee angle, knee moment and muscle activity. DESIGN: Randomised cross over. SETTING: University Laboratory. METHODS: Twenty females performed single-leg hop-landings onto sand, grass and firm surfaces. Kinematic, kinetic and muscle activity data were obtained. Compatibility curves were used to visualise parameter estimates alongside P- values, and S-value transforms. RESULTS: Knee angle for firm-sand (mean difference (d)‾ = -2.2°; 95% compatibility interval (CI): -4.6 to 0.28, p = 0.083, s = 3.6) and firm-grass (d‾ = -1.9; 95% CI: -4.3 to 0.5, p = 0.125, S = 3) yielded <4 bits of reputational information against the null hypothesis (H). 5 bits (p = 0.025) of information against H were observed for knee moment between firm-sand (d‾ = 0.17 N m/kg-1. m-1; 95% CI: 0.02 to 0.31) with similar effects for firm-grass (d‾ = 0.14 N m/kg-1. m-1; 95% CI: -0.02 to 0.29, p = 0.055, S = 4). Muscle activity across surfaces ranged from almost no (S = 1) reputational evidence against H (Quadriceps and Hamstrings) to 10-13 'bits' against H for lateral gastrocnemius (lower on sand). CONCLUSIONS: Our study provides valuable information for practitioners of the observed effect sizes for lower-limb landing mechanics across surfaces in asymptomatic females.

How is visual separation assessed? By counting distance units.

How does the human visual system assess the separation between pairs of stimuli in a frontal plane? According to the direct (or subtractive) view the system finds the difference between the positions of the stimuli in a localization system. According to the indirect (or additive) view the system finds the number of instances of a distance unit lying between representations of the stimuli. Critically, position is explicitly represented under the direct view, with separation being derived from position. Position is not explicitly represented under the indirect view; separation is consequently inferred by counting an internal unit of distance. Recent results favor the indirect over the direct view of separation assessment. Dissociations between assessments of separation and position, various context effects in the assessment of separation, and suggestions that position information is not cleanly accessed argue against the direct view. At the same time, various context effects in separation assessment argue for the indirect view. Recent findings regarding the brain bases of vision are consistent with the indirect view. In short, recent results suggest that assessing the separation between two frontal stimuli involves integrating distance units between representations of the stimuli.

Heel-to-toe drop effects on biomechanical and muscle synergy responses during uphill walking.

Uphill walking is a common task encountered in daily life, with steeper inclines potentially imposing greater biomechanical and neuromuscular demands on the human body. The heel-to-toe drop (HTD) in footwear may influence the biomechanical and neuromuscular pattern of uphill walking; but the impact remains unclear. Adjustments in HTD can modulate biomechanical and neuromuscular patterns, mitigating the demands and optimizing the body's response to different inclinations. We hypothesize that adjustments in HTD can modulate biomechanical and neuromuscular patterns, mitigating the demands and optimizing the body's response to different inclinations. Nineteen healthy men walked on an adjustable slope walkway, with varied inclinations (6°, 12°, 20°) and HTD shoes (10mm, 25mm, 40 mm), while the marker positions, ground reaction forces and electromyography data were collected. Our study reveals that gait temporo-spatial parameters are predominantly affected by inclination over HTD. Inclination has a more pronounced effect on kinematic variables, while both inclination and HTD significantly modulate kinetic and muscle synergy parameters. This study demonstrates that an increase in the inclination leads to changes in biomechanical and neuromuscular responses during uphill walking and the adjustment of HTD can modulate these responses during uphill walking. However, the present study suggests that an increased HTD may lead to elevated loads on the knee joint and these adverse effects need more attention.

Empagliflozin and Dapagliflozin Therapies Favorably Alter QRS-T Angle and Cardiac Repolarization Parameters in Patients with Heart Failure.

Recent randomized clinical trials demonstrated that treatment with sodium-glucose cotransporter-2 inhibitors (SGLT2is) reduces the risk of cardiac mortality due to sudden cardiac death and progressive pump failure in patients with heart failure (HF). Mechanisms underlying the potential anti-arrhythmic effects of SGLT2is are not well understood. We aimed to examine the effect of SGLT2i treatment on the frontal-plane QRS-T (f[QRS-T]) angle, a novel marker of myocardial repolarization and an independent predictor of adverse cardiac outcomes. The study included 106 patients with HF with reduced ejection fraction (HFrEF) who received an SGLT2i, empagliflozin, or dapagliflozin. All study participants underwent screening 12-lead electrocardiography (ECG) before and ∼90 days after treatment. We compared ECG repolarization parameters before and after treatment. During study enrollment, there were statistically significant decreases in the Tp-e/QT ratio (P ≤ .0001), Tp-e/corrected QT ratio (P = .0002), Tp-e interval (P < .0001), and f(QRS-T) angle (P = .04) in response to SGLT2i therapy. In addition, study participants experienced an improvement in functional capacity (2.06 ± 0.6 vs. 1.82 ± 0.6, P = .0001) and reduced N-terminal pro-b-type natriuretic peptide values. In this retrospective cohort study, SGLT2i therapy was associated with improved cardiac repolarization parameters in patients with HFrEF. More comprehensive studies are needed to evaluate the impact of SGLT2i on cardiac repolarization and its potential relation to cardiac arrhythmia and sudden cardiac death risk.

Joint line and knee osteotomy.

This review explores the intricate relationship between knee osteotomy and frontal plane joint line orientation, emphasizing the dynamic nature of the joint line's influence on knee forces and kinematics. Consideration of coronal alignments, knee phenotypes, and associated angles (medial proximal tibial angle (MTPA), lateral distal femoral angle (LDFA), joint line convergence angle (JLCA)) becomes crucial in surgical planning to avoid joint line deformities. The double-level osteotomy is to be considered a valid option, especially for severe deformities; however, the target patient cannot be selected solely based on high predicted postoperative joint line obliquity (JLO) and MPTA.

Musculoskeletal model degrees of Freedom: Frontal plane constraints are hindering our understanding of human movement.

Induced acceleration analyses have expanded our understanding on the contributions of muscle forces to center of mass and segmental kinematics during a myriad of tasks. While these techniques have identified a subset of major muscle that contribute to locomotion, most analyses have included models with only one frontal plane degree of freedom (dof) actuated by the hip joint. The purpose of this study was to define the impact of including knee and subtalar joint frontal plane dof on model superposition accuracy and muscle specific contributions to mediolateral accelerations. Induced acceleration analyses were performed using OpenSim with the Lai model on a freely available dataset of one subject running at 4 m/s. Analyses were performed on four models (standard, with subtalar joint, with frontal plane knee, and combined frontal plane knee with subtalar) with the kinematic constraint and perturbation analyses. Root mean square error and correlations were computed against experimental kinematics. Adding frontal plane dofs improved mediolateral acceleration correlations on average by > 0.25 while only minimally impacting errors. The constraints method performed better than the perturbation method for mediolateral accelerations. Including frontal plane knee dof resulted in muscle and method specific responses. All muscles presented with a complete flip of polarity for constraint method, imparted by allowing the medial/lateral muscles to contribute according to their anatomical function. Only the gluteus medius flipped for the perturbation method. This study provides significant support for the inclusion of frontal plane knee and subtalar dof and the need for reevaluation of muscle contributions via induced acceleration.

Frontal Plane Correction of Hallux Valgus Deformity With a Minimally Invasive Third Generation Tecnique: Short-Term Radiographic Outcomes of a Prospective Case Series.

A number of minimally invasive osteotomies have been described for the repair of hallux abducto valgus (HAV) deformities. However, there are no known published studies that evaluate the effects of minimally invasive surgery techniques on the reduction of frontal plane rotation in patients with HAV. The purpose of this study was to assess correction in the transverse and frontal planes in patients undergoing surgical repair of HAV deformity utilizing a modified percutaneous technique. One hundred and five feet in 105 patients with HAV deformity were treated with a third generation minimally invasive technique using a first metatarsal osteotomy that allowed for frontal plane correction in conjunction with an Akin osteotomy. The minimum follow-up time was 12 months. Preoperative and postoperative anteroposterior weightbearing x-ray images were assessed and four measurements were evaluated: hallux abductus angle (HAA), intermetatarsal angle (IMA), tibial sesamoid position and frontal plane rotation of the first metatarsal. There were statistically significant differences for each of the assessments between the preoperative and postoperative radiographs (p < .001). There was a mean reduction in the HAA of 23.5° ± 9.6°, in the IMA, 7.0° ± 3.5°, in the tibial sesamoid position, 2.6 ± 1.3, and an improvement in the assessment of first metatarsal pronation (1.4 ± 0.9). The overall complication rate was 18.1%, with 5.7% of the feet requiring reoperation. The minimally invasive procedure employed by the authors demonstrated suitable outcomes in reducing deformity in both the transverse and frontal planes.

Design, Characterization, and Preliminary Assessment of a Two-Degree-of-Freedom Powered Ankle-Foot Prosthesis.

Powered ankle prostheses have been proven to improve the walking economy of people with transtibial amputation. All commercial powered ankle prostheses that are currently available can only perform one-degree-of-freedom motion in a limited range. However, studies have shown that the frontal plane motion during ambulation is associated with balancing. In addition, as more advanced neural interfaces have become available for people with amputation, it is possible to fully recover ankle function by combining neural signals and a robotic ankle. Accordingly, there is a need for a powered ankle prosthesis that can have active control on not only plantarflexion and dorsiflexion but also eversion and inversion. We designed, built, and evaluated a two-degree-of-freedom (2-DoF) powered ankle-foot prosthesis that is untethered and can support level-ground walking. Benchtop tests were conducted to characterize the dynamics of the system. Walking trials were performed with a 77 kg subject that has unilateral transtibial amputation to evaluate system performance under realistic conditions. Benchtop tests demonstrated a step response rise time of less than 50 milliseconds for a torque of 40 N·m on each actuator. The closed-loop torque bandwidth of the actuator is 9.74 Hz. Walking trials demonstrated torque tracking errors (root mean square) of less than 7 N·m. These results suggested that the device can perform adequate torque control and support level-ground walking. This prosthesis can serve as a platform for studying biomechanics related to balance and has the possibility of further recovering the biological function of the ankle-subtalar-foot complex beyond the existing powered ankles.

Combined use of frontal plane QRS-T angle and platelet-to-lymphocyte ratio in the risk prediction of ischemic cardiomyopathy in STEMI.

BACKGROUND: Frontal plane QRS-T angle (fQRS-T) and platelet-to-lymphocyte ratio (PLR) are highly important parameters that well-predict unfavorable outcomes in patients with ST-elevated myocardial infarction (STEMI).There are limited data on the predictive significance of ischemic cardiomyopathy (I-CMP) from the combination of fQRS-T and PLR in STEMI, compared to using fQRS-T and PLR alone. AIM: We aimed to evaluate the ability of the combination of fQRS-T and PLR routinely obtained on admission to identify STEMI patients at risk of I-CMP. METHOD: Six hundred and thirty-eight consecutive patients with STEMI who underwent primary percutaneous coronary intervention between 2018 and 2021 were included. The assessment of I-CMP was conducted through two-dimentional (2D)-echocardiography 6 weeks post-STEMI and I-CMP was defined as a left ventricular ejection fraction (LVEF) of 50% or less. Multivariate logistic regression analysis and receiver operating curve (ROC) analysis were performed to predict the development of I-CMP. RESULTS: In ROC analysis, the cut-off values of fQRS-T and PLR for best predicting I-CMP were 66.72° and 101.23, respectively. The model using the combination of two markers was the most powerful predictor of I-CMP risk (OR: 3.183, 95% CI: 1.971-5.139, p = .001) when included in a single variable such as high fQRS-T or high PLR (OR: 1.422, 95% CI: 0.870-0.232, p = .160). Additionally, the concomitant presence of high fQRS-T and high PLR exhibited the highest specificity (77%) for I-CMP relative to the individual presence of high fQRS-T (66%) or PLR (49%). CONCLUSION: The combination of fQRS-T and PLR, which is a simple and cost-effective risk assessment, may serve as a more reliable prognosticator for I-CMP as opposed to the use of fQRS-T and PLR alone for STEMI.

Thorax, pelvis and hip pattern in the frontal plane during walking in unilateral transtibial amputees: biomechanical analysis

Background: Lower limb amputees exhibit postural control deficits during standing which can affect their walking ability. Objectives: The primary purpose of the present study was to analyze the thorax, pelvis, and hip kinematics and the hip internal moment in the frontal plane during gait in subjects with Unilateral Transtibial Amputation (UTA). Method: The participants included 25 people with UTA and 25 non-amputees as control subjects. Gait analysis was performed using the Vicon(r) Motion System. We analyzed the motion of the thorax, pelvis, and hip (kinematics) as well as the hip internal moment in the frontal plane. Results: The second peak of the hip abductor moment was significantly lower on the prosthetic side than on the sound side (p=.01) and the control side (right: p=.01; left: p=.01). During middle stance, the opposite side of the pelvis was higher on the prosthetic side compared to the control side (right: p=.01: left: p=.01). Conclusions: The joint internal moment at the hip in the frontal plane was lower on the prosthetic side than on the sound side or the control side. Thorax and pelvis kinematics were altered during the stance phase on the prosthetic side, presumably because there are mechanisms which affect postural control during walking. .