Differences and relationships between weightbearing and non-weightbearing dorsiflexion range of motion in foot and ankle injuries.

Background: This study aimed to: (1) identify assessment methods that can detect greater ankle dorsiflexion range of motion (DROM) limitation in the injured limb; (2) determine whether differences in weightbearing measurements exist even in the absence of DROM limitations in the injured limb according to non-weightbearing measurements; and (3) examine associations between DROM in the weightbearing and non-weightbearing positions and compare those between a patient group with foot and ankle injuries and a healthy group.

Methods: Eighty-two patients with foot and ankle injuries (e.g.

Differences in abductor hallucis activity during running in individuals with chronic ankle instability and copers.

Background: Assessment of neuromuscular dysfunction following a lateral ankle sprain during running typically focuses on the activities of the extrinsic foot muscles. Although the interaction between intrinsic and extrinsic foot muscles has been reported, there are no studies on the activities of intrinsic foot muscles in individuals with chronic ankle instability and ankle sprain copers.

Research Question: Do copers and individuals with chronic ankle instability (CAI) have different abductor hallucis activity?

Methods: This study included 11 controls, 11 copers, and 16 CAI participants.

Lower-limb sagittal joint angles during gait can be predicted based on foot acceleration and angular velocity.

Background And Purpose: Continuous monitoring of lower-limb movement may help in the early detection and control/reduction of diseases (such as the progression of orthopedic diseases) by applying suitable interventions. Therefore, it is invaluable to calculate the lower-limb movement (sagittal joint angles) while walking daily for continuous evaluation of such risks. Although cameras in a motion capture system are necessary for calculating lower-limb sagittal joint angles during gait, the method is unrealistic considering the setting is difficult to achieve in daily life.

Center of Pressure Deviation during Posture Transition in Athletes with Chronic Ankle Instability.

Center of pressure (COP) tracking during posture transition is an ideal scale for determining the recurrence of an ankle injury, thereby preventing chronic ankle instability (CAI). However, the same is difficult to determine because the reduced ability of certain patients (who experienced sprain) to control posture at the ankle joint is masked by the chain of hip and ankle joint motion. Thus, we observed the effects of knee joint immobilization/non-immobilization on postural control strategies during the posture transition task and attempted to evaluate the detailed pathophysiology of CAI.

Relationship between Changes in Foot Arch and Sex Differences during the Menstrual Cycle.

This study investigated the relationship between changes in foot characteristics and sex differences during the menstrual cycle in healthy male and female university students. We examined 10 female subjects and 14 male subjects. The menstrual cycle was divided into the three phases: the early follicular phase, ovulatory phase, and luteal phase via basal body temperature, an ovulation kit, and salivary estradiol and progesterone concentration measurements.

Effect of change in patellofemoral joint contact area by the decrease in vastus medialis muscle activation on joint stress.

Purpose: Patellofemoral pain syndrome is a common orthopedic trauma among runners. It is unclear whether patellofemoral joint stress (PFJS) is the highest (or lowest) when the knee joint flexion angle and extension moment are in combination under the condition that vastus medialis (VM) activation decreases. This study aimed to investigate the effects of changes in the PFJ contact area by decreasing the activation of the VM muscle on PFJS.

Estimation of lower-limb sagittal joint moments during gait using vertical ground reaction force.

Lower-limb sagittal joint moments during gait are important variables for evaluating the risk of disease progression, such as that of orthopedic diseases. Therefore, quantifying lower-limb sagittal joint moments during walking is important to continuously evaluate the risk of disease progression. A motion capture system and force plate are employed in the calculation of lower-limb sagittal joint moments during gait.

Differences in the coordination and its variability among foot joints during running in neutral foot and flatfoot.

Flatfoot is a well-known foot deformity, with a prevalence of 11.2%-29.0% among adults.

Coper has altered foot joint coordination pattern compared to individuals with chronic ankle instability during running.

Background: There is limited information regarding the cause for the different etiologies in individuals with initial lateral ankle sprains (LAS) who have chronic ankle instability (CAI) and no recurrence or instability for > 12 months (copers) following initial LAS. Assessing the movement patterns of copers and individuals with CAI and LAS recurrence is essential for identifying the mechanical factors that affect patient outcomes.

Research Question: Does coordination and coordination variability of rearfoot, midfoot, and forefoot present a potentially causative pattern for CAI or coper?

Methods: This cross-sectional study included 35 males who were divided into the CAI (n = 13), coper (n = 12), and control group (n = 10).

Immediate Effects of Stabilization Exercises on Trunk Muscle Activity during Jump Header Shooting: A Pilot Study.

This study aimed to clarify trunk muscle activity during jump header shooting and examine the immediate effects of trunk stabilization exercises on trunk muscle activity. Nineteen males who had played soccer for over 5 years were assigned to either the trunk stabilization exercise group or the control group. Muscle activity during jump header shooting was measured before and after intervention.

Effect of Arch Height Flexibility in Individuals With Flatfoot on Abductor Hallucis Muscle Activity and Medial Longitudinal Arch Angle During Short Foot Exercises.

Flatfoot presents decreased medial longitudinal arch (MLA), and such foot deformity involves intrinsic foot muscles dysfunction. Flatfoot can be classified into flexible and stiff types according to arch height flexibility (AHF). Short foot exercise (SFE) is an intrinsic foot muscle strengthening exercise, which is reportedly effective against flatfoot.

Copers exhibit altered ankle and trunk kinematics compared to the individuals with chronic ankle instability during single-leg landing.

Copers are individuals who have had a lateral ankle sprain but have no history of recurrent lateral ankle sprain, residual symptoms, or functional disability. Copers have shown no significant difference in lower limb kinematics in landing for proactive conditions compared with a control (CTR) group. However, the copers (CPR) group has shown differences compared to CTR and chronic ankle instability (CAI) groups for dynamic balance conditions, suggesting that the trunk may compensate for foot instability during shock absorption.

Influence of sex and knee joint rotation on patellofemoral joint stress.

Purpose: Females are two times as likely to experience patellofemoral pain syndrome (PFPS) than males, however, the reason for this difference between sexes remains unclear. Patellofemoral joint (PFJ) stress is believed to contribute to PFPS alterations through knee joint rotation alignment, but the influence of knee joint rotation conditions on PFJ stress is unclear. We aimed to investigate the influence of sex and knee joint rotation alignment on PFJ stress.

Copers adopt an altered dynamic postural control compared to individuals with chronic ankle instability and controls in unanticipated single-leg landing.

Background: Several prior studies involving "expected" single-leg landings have not succeeded in establishing a difference between copers and a control group.

Research Question: Does expected and unanticipated single-leg landing affect dynamic postural stability in lateral ankle sprain individuals with chronic ankle instability (CAI), copers, and controls?

Methods: In this prospective cross-sectional study, physically active adults with CAI (n = 12), copers (n = 12), and controls (n = 12) were included. Participants performed expected single-leg landing by stepping off a 30-cm box.

Effects of step length and cadence on hip moment impulse in the frontal plane during the stance phase.

Background: An excessive daily cumulative hip moment in the frontal plane (determined as the product of hip moment impulse in the frontal plane during the stance phase and mean number of steps per day) is a risk factor for the progression of hip osteoarthritis. Moreover, walking speed and step length decrease, whereas cadence increases in patients with hip osteoarthritis. However, the effects of step length and cadence on hip moment impulse in the frontal plane during the stance phase are not known.

Number of fiber bundles in the fetal anterior talofibular ligament.

Purpose: For the anterior talofibular ligament (ATFL), a three-fiber bundle has recently been suggested to be weaker than a single or double fiber bundle in terms of ankle plantarflexion and inversion braking function. However, the studies leading to those results all used elderly specimens. Whether the difference in fiber bundles is a congenital or an acquired morphology is important when considering methods to prevent ATFL damage.

Classification by degree of twisted structure of the fetal Achilles tendon.

Background: The purpose of this study was to classify the twisted structure of the fetal Achilles tendon.

Methods: The study was conducted using 30 legs from 15 Japanese fetuses (mean weight, 1764.6 ± 616.

Individuals with chronic ankle instability exhibit altered ankle kinematics and neuromuscular control compared to copers during inversion single-leg landing.

Objectives: This study compares the ankle kinematics and muscle activities of the individuals with chronic ankle instability (CAI), coper, and control groups in normal and inversion single-leg landings.

Design: cross-sectional study; SETTING: Biomechanics laboratory.

Participants: Physically active adults with CAI (N = 12); and coper (N = 12) and control (N = 12) groups.

Copers adopt an altered movement pattern compared to individuals with chronic ankle instability and control groups in unexpected single-leg landing and cutting task.

Individuals with chronic ankle instability (CAI) demonstrate altered ankle kinematics during landing compared to uninjured individuals. However, if copers may have adopted unique movement strategy to prevent repeated ankle sprains is unclear. The purpose of this study compares the lower-extremity joint kinematics and muscle activities of CAI (N = 8), coper (COP) (N = 8), and control (CON) (N = 8) groups in unexpected single-leg landing and cutting.

Morphological characteristics of the plantar calcaneocuboid ligaments.

Background: The aim of this study was to clarify the differences in morphological features between the long plantar ligament (LPL) and the short plantar ligament (SPL).

Methods: This investigation examined 50 legs from 25 Japanese cadavers. The LPL and SPL of each leg were classified into one of three types based on the shape and number of fiber bundles.

Shank and rearfoot coordination and its variability during running in flatfoot.

Flatfoot is a risk factor for patellofemoral pain syndrome (PFPS), and excessive rearfoot eversion occurring in flatfoot has been associated with the development and progression of PFPS; however, the mechanism remains unclear. This study aimed to investigate transverse shank and frontal rearfoot coordination patterns and variability when running with normal foot and flatfoot. Participants with normal foot (n = 13) and flatfoot (n = 13) were asked to run at their preferred speed.

Differences in rearfoot, midfoot, and forefoot kinematics of normal foot and flatfoot during running.

Flatfoot is a common foot deformity, which could contribute to running injuries such as medial tibial stress syndrome. Intrafoot kinematics of flatfoot during walking have often been documented using multisegment foot models. However, the intrafoot kinematics of flatfoot during running remains unclear, despite the possible relationship between flatfoot and running injuries.