Chronic Ankle Instability (CAI) is a common musculoskeletal condition characterized by recurring ankle sprains and impaired postural control (PC). Understanding the relationship between ankle muscle ...strength, PC, and the role of pain is essential for effective management.
This prospective cross sectional study aimed to 1. Compare ankle isometric muscle strength (IMS) and PC between CAI and asymptomatic sides. 2. Assess the correlations between ankle IMS and PC and explore the potential mediating effect of pain in individuals with CAI.
A total of 44 individuals with CAI, were enrolled in the study. Ankle IMS (dorsiflexors, plantar flexors, invertors, and evertors) was measured using a dynamometer, while PC was evaluated using sway parameters (anterior-posterior and medial-lateral sway, ellipse area). Pain levels were reported using a Visual Analog Scale.
The CAI ankles exhibited significantly lower ankle IMS in all muscle groups compared to the asymptomatic ankles (p < 0.001). Additionally, the CAI side showed increased postural sway and a larger ellipse area (p < 0.001), indicating reduced PC. Negative correlations were observed between ankle IMS and PC parameters on the CAI side, with dorsiflexor strength showing correlations ranging from −0.423 to −0.387, plantar flexor strength ranging from −0.423 to −0.371, invertor strength ranging from −0.412 to −0.238, and evertor strength ranging from −0.451 to −0.365 (p < 0.001). Mediation analysis revealed that pain played a significant mediating role in connecting ankle IMS and PC parameters among individuals with CAI, with statistical significance (p < 0.05).
Individuals with CAI exhibit weaker ankle IMS and diminished PC in comparison to their healthy side. Moreover, pain was identified as a mediator in the relationship between ankle IMS and PC in CAI. These findings underscore the importance of addressing both ankle IMS and pain in the rehabilitation and management of CAI.
•Chronic ankle instability (CAI) Weakens Ankle Strength and Control.•Pain Mediates Ankle Health in CAI.•Integrated study informs rehabilitation.•Effective strategies for CAI care.
Greater peak torque and higher myotendinous density at the ankle are associated with a more plate-like architecture at the distal tibia.
In this cross-sectional study, women and men ≥ 50 years old ...with no metal implants, reconstructive surgery, muscular dystrophies, or tendinopathies in any leg were recruited by convenience. Isometric ankle dorsi-plantar flexion and inversion-eversion peak torques were measured using dynamometry. HR-pQCT distal tibia scans were completed. Both assessments were completed on the same day on the non-dominant leg. Integral and trabecular vBMD were derived from standard analyses, failure load (FL) was obtained from finite element analysis, plate-specific parameters were computed from individual trabecula segmentation (ITS) analysis, myotendinous density (MyD) and volume fraction (MyV/TV) were computed from soft tissue analysis. pQCT scans of the 66 % mid-leg were performed (500 μm at 15 mm/s) to obtain muscle density (MD) and muscle cross-sectional area (MCSA).
General linear models estimated how ankle muscle group torque and muscle size and density differentially related, both separately and together, to whole-bone properties (integral vBMD, FL) and trabecular morphometry (ITS plate parameters). Models were adjusted for age, sex, BMI, use of glucocorticoids, current osteoarthritis, and participation in moderate to vigorous recreational or sport activities.
Among 105 participants (77 % female, mean age: 63 (10) years, BMI: 25.8 (5.4) kg/m2, 25 % with OA, 17 % fracture history, 42 % falls history), all torque measures, particularly ankle dorsiflexion and eversion, were correlates of plate-plate/rod junction density and failure load. However, muscle size and density measures were further associated with vBMD. The effect of greater ankle flexor-extensor torque on more connected bone was stronger when MyD was higher (interaction p < 0.001).
Strength of muscles around the ankle are correlates of plate-like trabeculae at the distal tibia, while leaner muscle and myotendinous tissues facilitates better quality bone for stronger ankle muscle torque.
•Higher myotendinous tissue density is related to more intact plate-plate/rod connectivity.•Greater ankle flexor torque is a strong correlate of trabecular connectivity but not vBMD.•Myotendinous tissue and torque together explain greater variance in trabecular connectivity.•Stronger torque is better associated with failure load when myotendinous tissues are leaner.•Strengthening ankle flexors may help bone integrity if also reducing myotendinous tissue fat.
Much remains unclear about how chronic ankle instability (CAI) could affect knee muscle activations and interact with knee biomechanics. Therefore, the purpose of this study was to assess the ...influence of CAI on the lower extremity muscle activation at the ankle and knee joints during landings on a tilted surface. A surface electromyography system and two force plates were used to collect lower extremity muscle activation of 21 young female individuals with CAI and 21 pair-matched controls during a double-leg landing with test limb landing on the tilted surface. In the pre-landing phase, compared to controls, CAI participants displayed a reduced ankle evertor activation that could place CAI at a high risk of giving way or sprain injury. In the landing phase, an increased tibialis anterior activation of CAI led to increased co-contraction of ankle muscles in the sagittal and frontal plane. A greater ankle muscle co-contraction could increase the ankle stability during landings but may adversely influence the knee muscle activations (e.g., a greater co-contraction ratio of quadriceps to hamstrings). Relevant training programs (e.g., increasing pre-landing peroneal activation, and optimizing activation ratio of quadriceps to hamstrings) may help individuals with CAI improving ankle stability and reduce atypical knee loading during landings.
PURPOSE The purpose of this study is to analyze the biomechanical variables involved in ballet dancers’ ankle muscle imbalance when performing relevé movements. METHODS The subjects of this study ...(n=14, age: 22.29±1.73 years old, height: 161.4±5.06cm, weight: 51.88±7.51kg) were 14 ballet dancers with 9 years of experience. Based on the reciprocal muscle strength ratio, the dancers were divided into the following groups: Close to the normal value (RMIS) and far from the normal value (RMIB) using the maximum values of plantar flexion and dorsiflexion of the ankle joint using an isokinetic measurement equipment (60°/sec). RMIB). The biomechanical variables, namely the ankle joint movement and ground reaction force, were subsequently measured. SPSS 26.0 was used for data analysis and independent t-test was used for statistical verification. RESULTS The ground reaction force in the Z (vertical) direction based on the ankle joint muscle strength imbalance of ballet dancers was significantly lower in the RMIB group. In addition, although it was not a statistically significant difference, the plantar flexion movement was lower in the RMIB group, and there was a significant difference in the generation of ankle joint movement in the Z direction. CONCLUSIONS In conclusion, in order for a ballet dancer to efficiently utilize the force generated from the supporting leg when performing a movement, ankle imbalance must be taken into consideration when training.
Purpose The purpose of this study was to examine the effects of increasing physical activity on foot structure and ankle muscle strength in adults with obesity and to verify whether the rate of ...change in foot structure is related to that in ankle muscle strength. Subjects and Methods Twenty-seven adults with obesity completed a 12-week program in which the intensity of physical activity performed was gradually increased. Physical activity was monitored using a three-axis accelerometer. Foot structure was assessed using a three-dimensional foot scanner, while ankle muscle strength was measured using a dynamometry. Results With the increasing physical activity, the participants’ feet became thinner (the rearfoot width, instep height, and girth decreased) and the arch became higher (the arch height index increased) and stiffer (the arch stiffness index increased); the ankle muscle strength also increased after the intervention. Additionally, the changes in the arch height index and arch stiffness index were not associated with changes in ankle muscle strength. Conclusion Increasing physical activity may be one possible approach to improve foot structure and function in individuals with obesity.
ADJUST, a novel ankle-foot orthosis (AFO) that we have developed, allows the ankle a normal range of motion (ROM) while providing support for flaccid ankle-muscle paresis. It consists of two ...leaf-spring hinges that independently control plantarflexion and dorsiflexion stiffness. To evaluate whether ADJUST meets the minimum mechanical requirements, we quantified its ankle ROM and stiffness. To evaluate whether it meets the minimum ankle kinematic and kinetic goals for normal gait, a patient with both plantarflexor and dorsiflexor paralysis used it, and his own AFO, to walk. When fitted with stiff springs, ADJUST met all requirements and goals. During the stance and the swing phases, ankle ROM was within the normal range when ADJUST was fitted with stiff springs. Ankle ROM during stance was outside the normal range both with the patient's own AFO and with ADJUST when it was fitted with flexible springs. Power at the ankle met the minimum goal but was lower with ADJUST than with the patient's own AFO. The optimal stiffness configuration that would result in a higher power at the ankle with a normal ankle ROM was not reached for this patient. Walking with ADJUST seems feasible and could be profitable in patients with flaccid ankle muscle paresis.
Purpose To examine the influence of dorsolateral prefrontal cortex (DLPFC) activation, ankle muscle activities, and coactivation on postural steadiness during dual-tasks. Participants and Methods A ...total of 14 participants (8 males, 6 females) were included. The participants stood straight on the force plate, and performed 3 different tasks: 1) a quiet standing (single-task), 2) a repetition of a number (dual-task 1: DT1), and 3) a serial subtraction (dual-task 2: DT2). We divided the participants into 2 groups (S and L group) according to whether their center of pressure paths in the dual-tasks were shorter or longer than those in the single-task. The EMG activity of the gastrocnemius lateralis and tibialis anterior were measured; the oxygenated hemoglobin (oxy-Hb) level in the DLPFC were measured using fNIRS. Results The results revealed that oxy-Hb in the left DLPFC increased significantly in all participants during DT2 compared to a single-task. Further, we found that the S group exhibited a higher rate of tibialis anterior activity and ankle muscle coactivation than the L group during DT2. Conclusion We concluded that the increase of the DLPFC activation varied with the dual-tasks; moreover, younger individuals modulate their standing posture using different strategies for posture steadiness during posture-calculating task.
목적 본 연구의 목적은 발레 무용수의 발목 근육 불균형에 따른 를르베 동작 수행 시 운동 역학적 변인을 분석하는 것이다.
방법 본 연구의 대상자(n=14, 나이: 22.29±1.73세, 신장: 161.4±5.06cm, 체중: 51.88±7.51kg)는 경력 9년의 발레 무용수 14명이다. 동측 근력비는 등속성 측정기(60°/sec)를 이용하여 발목관절의 ...족저 굴곡과 배측 굴곡의 최대값을 이용하여 정상치에 가까운 그룹(RMIS)과 먼 그룹(RMIS)으로 집단을 구분하였다. 운동 역학적 변인으로는 발목관절 모멘트와 지면반력을 측정하였다. 데이터 분석은 SPSS 26.0을 사용하였고 통계적 검증은 독립 t-검정을 사용하였다.
결과 발레 무용수의 발목관절 근력 불균형에 따른 Z(수직)방향 지면반력은 RMIB군에서 유의하게 낮게 나타났다. 또한, 통계적으로 유의한 차이는 아니었지만 족저굴곡 모멘트는 RMIB군에서 더 낮게 나타났고, Z방향 발목관절 모멘트 발생에서도 유의한 차이가 나타났다.
결론 발레 무용수가 동작을 수행할 때 지지 다리 측에서 발생한 힘을 효율적으로 활용하기 위해서는 발목 불균형을 고려한 훈련이 필요하다.
PURPOSE The purpose of this study is to analyze the biomechanical variables involved in ballet dancers’ ankle muscle imbalance when performing relevé movements. METHODS The subjects of this study (n=14, age: 22.29±1.73 years old, height: 161.4±5.06cm, weight: 51.88±7.51kg) were 14 ballet dancers with 9 years of experience. Based on the reciprocal muscle strength ratio, the dancers were divided into the following groups: Close to the normal value (RMIS) and far from the normal value (RMIB) using the maximum values of plantar flexion and dorsiflexion of the ankle joint using an isokinetic measurement equipment (60°/sec). RMIB). The biomechanical variables, namely the ankle joint movement and ground reaction force, were subsequently measured. SPSS 26.0 was used for data analysis and independent t-test was used for statistical verification. RESULTS The ground reaction force in the Z (vertical) direction based on the ankle joint muscle strength imbalance of ballet dancers was significantly lower in the RMIB group. In addition, although it was not a statistically significant difference, the plantar flexion movement was lower in the RMIB group, and there was a significant difference in the generation of ankle joint movement in the Z direction. CONCLUSIONS In conclusion, in order for a ballet dancer to efficiently utilize the force generated from the supporting leg when performing a movement, ankle imbalance must be taken into consideration when training.
BACKGROUND: There continues to be ongoing debates among researchers as to the positive or negative effects of short-term wearing of high heeled shoes (HH) on ankle muscles. OBJECTIVE: To investigate ...ankle functions among people wearing low-, mid-, and high-heel shoes as well as the effects different heel measurement heights have among the groups. METHODS: Seventy-eight female college students who habitually wore heeled shoes at various heights from 2.71 to 10.15 cm for approximately one academic year (40.10 ± 10.13 weeks) took part in this study. Participants were grouped according to their heel heights: low-, mid- and high-heels. Body composition was measured as well as the isokinetic strength of ankle muscles at three different heights: 0 cm, 5 cm and 10 cm, relating to the distance between the standard foot attachment and the foot supporting plate. The isokinetic strength (in Nm) of the ankle dorsiflexor (DF), plantarflexor (PF), evertor (EV), and invertor (IV) muscle groups was recorded for the dominant and non-dominant sides. The total strength of ankle muscles (TSAM), which is the sum of the peak moment of all 4 muscle groups was calculated for both sides for all groups. RESULTS: The wearing of HH shoes significantly enhanced the isokinetic strength of all ankle muscles when measured at a height of 0 cm, and some ankle muscles (PF and EV) when measured at a height of 5 cm. However, these effects decreased as the measurement height increased for DF, PF, EV and IV (P< 0.05) for both sides. Moreover, there were no significant differences between high- and low-heels groups at the measurement height of 10 cm. The TSAM for both sides also showed no significant differences between groups when measuring at 10 cm. CONCLUSIONS: Wearing of HH shoes for one year may contribute to enhancing the isokinetic strength of ankle muscles when wearing flat or mid-heeled shoes. However, the positive effects that were measured in lower height conditions (0 cm and 5 cm) disappeared when measured using higher heights, indicating that wearing HH shoes yields no benefits for building ankle muscle strength.
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