The relationship between trunk control, spinal posture, and spinal mobility in patients with multiple sclerosis: a cross-sectional study.

Background/aim: Trunk control, which plays a key role in balance and mobility, decreases in patients with multiple sclerosis (PwMS) and many parameters such as sensory, motor, and musculoskeletal systems affect trunk control. The aim of this study was to compare trunk control, spinal mobility, and spinal posture in PwMS with healthy controls and investigate the relationship between trunk control with spinal posture and spinal mobility in PwMS. Materials and methods: The study was completed with 38 PwMS and 38 healthy controls with matched age and sex. Trunk control was evaluated with the Trunk Impairment Scale (TIS). Spinal posture and mobility were evaluated in sagittal and frontal planes using an IDIAG M360 Spinal Mouse. Spinal posture was evaluated in upright, maximum flexion, extension, left and right lateral flexion positions, and spinal mobility was evaluated from upright to flexion, extension, right and left flexion positions in sagittal and frontal planes. Results: TIS scores, thoracic mobility angles (from upright to flexion and left lateral flexion), lumbar mobility angles (from upright to extension and right lateral flexion) and lumbar posture angle (maximum right lateral flexion) were lower, and thoracic posture angles (upright and maximum extension) were higher in PwMS than healthy controls (p < 0.05). No significant difference was found between other spinal postures and mobility values. In addition, there was only a negative relationship between thoracic spinal mobility from upright to extension and trunk control in PwMS (r = -0.349; p = 0.032). Conclusion: These findings indicate the importance of early detection of trunk disturbances in PwMS. Thus, even in the early stages of multiple sclerosis, detailed trunk assessment will guide the implementation of comprehensive exercise programs.

An investigation of neck pain in older adults, and its relation with shoulder position sense and upper extremity function.

PURPOSE: Neck pain is a musculoskeletal problem increasing with age. The disorders that occurs in the neck region may also affect the upper extremity due to its close anatomical relationships. The aim of this study was to determine whether neck pain affects shoulder position sense and upper extremity function in the older adults. METHODS: This cross-sectional study was carried out in nursing homes. The older adults over 65 years of age with chronic neck pain for the last 6 months were included. Pain intensity was evaluated with a Visual Analog Scale. Acumar dual digital inclinometer was used for the evaluation of shoulder position sense. 9-Hole Peg Test was used for the measure of upper extremity function. RESULTS: It was found dominant side shoulder position sense and the function of both upper extremities were different between the three groups (p < 0.05). Pain was correlated with dominant and non-dominant 60ᵒ flexion shoulder position sense and 60ᵒ abduction shoulder position sense (p < 0.05). Additionally, a relationship was found only between pain and non-dominant side upper extremity function (p < 0.05). CONCLUSION: In conclusion, we found that in older adults with neck pain, position sense and function decreased in upper extremities. The findings from this study support that detailed evaluation of anatomically related regions as well as the cervical region where pain is felt is important in creating a more effective rehabilitation program.

Effects of cadence-compatible melodic rhythmic auditory stimulation implementation on gait in patients with Parkinson's disease.

PURPOSE: Progressive loss of dopaminergic neurons in basal ganglia is blamed as the main source of gait disturbance in Parkinson's disease (PD). It is known that the normal step pattern does not disappear in PD, but there is a problem in activating the correct step response. The aim of this study was to investigate the effect of Rhythmic Auditory Stimulation (RAS), which is an external stimulus, on gait in individuals with PD. MATERIALS AND METHODS: Twenty-six individuals, 13 in the PD group and 13 in the control group, participated in the study. All individuals were asked to walk under four different RAS conditions configured with beat frequency and melodic variations. Time-distance parameters and gait performance of the individuals were evaluated. RESULTS: RAS significantly increased the gait speed of the individuals with PD compared to the control group. RAS set to 10% increase in the cadence of the patient with melody (10 M+) was found to be more effective than the RAS set to normal cadence of the patient without melody (0 M-) (p < 0.05). While all RAS implementations increased the stride length of the individuals with PD (p < 0.05), there was no change in the control group. RAS did not affect the return time in both groups. CONCLUSIONS: Our study has shown that RAS implementation improves gait in individuals with PD both in terms of time-distance parameters and performance, especially when set to 10% more than the patient's gait cadence. It was concluded that cadence-compatible melodic RAS can be safely included in PD rehabilitation programs.

Investigation of non-motor symptoms, balance, muscle strength, and functional mobility in patients with parkinson's disease.

PURPOSE: Although both motor symptoms and non-motor symptoms (NMSs) occur in patients with Parkinson's disease (PD), clinical practice focuses more on motor symptoms. The aim of this study was to examine balance, muscle strength, and mobility in relation with NMSs in patients with PD. The other aim of this study was to investigate the relationship between NMSs and muscle strength, balance, and functional mobility in PD. MATERIALS AND METHODS: The study included 24 patients with PD (between Hoehn & Yahr Stage 1 and 3) and 20 healthy individuals of similar age and sex. The participants' balance was assessed with the Biodex Balance System (Biodex Medical Systems, Shirley, NY, USA), muscle strength assessments were conducted with a Biodex® System 4 Dynamometer device, and functional mobility was assessed with the Timed Up and Go test (TUG). The non-motor symptoms scale was used for NMSs. RESULTS: We found that lower extremity strength scores were lower and NMSs, balance, and mobility scores were greater in patients with PD in comparison to healthy controls (p < 0.05). The correlation analysis revealed that higher NMSs were related to reduced knee extension strength and cognitive dual task performance. CONCLUSION: Although no relationship between NMSs and balance was observed, the relationship between the TUG + cognitive task and muscle strength suggests that NMSs should be carefully evaluated along with the motor symptoms, which deteriorate beginning with the early period.

The relationship of pain, anxiety, and fatigue with knee position sense, balance, and dual task performance during menstrual cycle in females with multiple sclerosis.

PURPOSE: This study was carried out to investigate the relationship of pain, anxiety, and fatigue with position sense, balance, and dual task performance during the menstrual cycle in females with multiple sclerosis. METHODS: This study included 14 females with multiple sclerosis with regular menstrual cycles. The individuals' position sense, balance, and dual task performance were evaluated with a digital inclinometer, Biodex Balance System, and the Time Up and Go Test, respectively. Pain, anxiety, and fatigue were assessed with the Visual Analogue Scale, State-Trait Anxiety Inventory, and Fatigue Severity Scale, respectively. The study protocol was registered at http://clinicaltrials.gov (NCT04408742). RESULTS: In the early follicular phase, the pain was correlated with right knee position sense, and pain + activity was correlated with right knee position sense and dual task performance (p < .05). The correlation analysis revealed that no correlation was found between pain, pain + activity, anxiety, and fatigue, and position sense, balance, and dual task performance in the ovulation phase. In the luteal phase, the right knee position sense was correlated with pain, pain + activity, and fatigue (p < .05). Similarly, the left knee position sense was correlated with pain, pain + activity, and fatigue (p < .05). CONCLUSIONS: As a result, there may be a relationship between pain and position sense in the early follicular phase and luteal phase, and a relationship between pain and motor dual task performance in the early follicular phase. Considering these changes occurring in different phases of the menstrual cycle, we think that each phase of the menstrual cycle should be taken into consideration in the follow-up of physiotherapy evaluations in females with multiple sclerosis. Abbreviations: MS: multiple sclerosis; CNS: central nervous system; FwMS: females with multiple sclerosis; eFP: early follicular phase; OP: ovulation phase; LP: luteal phase.

An investigation of upper extremity function in patients with multiple sclerosis, and its relation with shoulder position sense and disability level.

Purpose: The purposes of this study were to investigate upper extremity function and shoulder position sense in patients with multiple sclerosis and its relation with disability level. Materials and methods: In this study, 20 multiple sclerosis and 20 healthy subjects participated. The disability level was determined by the Expanded Disability Status Scale. Mental state was assessed using the Mini-Mental State Examination. Upper extremity function was measured with the 9-Hole Peg Test and shoulder position sense was evaluated with a Dualer IQTM digital inclinometer. The study protocol was also registered at http://clinicaltrials.gov (NCT03846336). Results: Upper extremity function scores were lower and shoulder position sense error scores were greater in patients with multiple sclerosis in comparison to healthy controls (p < .05). While disability level was associated with dominant and non-dominant upper extremity function, no relationship was found between the disability level and shoulder position sense (p < .05). Only the dominant side shoulder position senses at 30° and 60° abduction were found to be associated with upper extremity function (p < .05). Conclusions: These results indicate that shoulder position sense and upper extremity function were affected in patients with multiple sclerosis with mild to moderate disability. Upper extremity functions were associated with shoulder abduction joint sense in patients with multiple sclerosis. In the assessment of upper extremity functions, joint position sense should be taken into account even at early stages of multiple sclerosis, so it may provide guidance in planning rehabilitation programs.

Effects of Low-Frequency Repetitive Transcranial Magnetic Stimulation on Swallowing Function and Quality of Life of Post-stroke Patients.

Repetitive transcranial magnetic stimulation (rTMS) is one of the non-invasive techniques, which is used to modulate cortical regions in patients with stroke. The aim of this single blind, controlled study was to investigate the effect of rTMS on swallowing function and quality of life of mono-hemispheric post-stroke patients with dysphagia. Twenty-eight patients were randomized and split between study and control group. Each group received conventional dysphagia rehabilitation 3 days a week for 4 weeks, and study group also received 1 Hz rTMS to unaffected hemisphere in the final week. The descriptive information was noted. The clinical and radiological swallowing evaluation and quality of life assessment have been performed at four different times including before and after the treatment, 1 month and 3 months after the treatment. At baseline, no significant differences were observed between groups in terms of demographic and clinical features (p > 0.05). Swallowing function and quality of life of the patients were statistically improved in both groups towards the third month (p < 0.05). Swallowing function was comparable between two groups. However, a significant improvement was observed on appetite, fear of eating, and mental health parameters of quality of life assessment in the study group compared to the control group (p < 0.05). In conclusion, despite positive changes in some aspects of quality of life, rTMS did not enhance the swallowing function when compared conventional dysphagia rehabilitation. Therefore, the application of 1 Hz rTMS should be reconsidered to improve swallowing function in the chronic period.

Three different points of view in stroke rehabilitation: patient, caregiver, and physiotherapist.

BACKGROUND: The similarities or differences of the three some (physiotherapists, patients, and caregivers) thought about the process of stroke rehabilitation can play a key role in the success of rehabilitation. OBJECTIVE: The aim of this qualitative study was to investigate the perspectives of the three some, with regard to the two themes of the study: (1) What are the problems faced by the patients after stroke?; and (2) What does recovery after stroke mean to you? METHODS: The qualitative questions and possible answers were prepared by four physiotherapists. The answers were matched to International Classification of Functioning (ICF) components. Seventy patients who were having treatment as in-patient rehabilitation centers, their caregivers, and physiotherapists were invited to the study. After the questions were asked and the possible response choices were presented, subjects were asked to prioritize these response choices. RESULTS: One hundred and fifty-nine subjects, including 53 patients, 53 caregivers, and 53 physiotherapists, were included to the study. When the theme 1 were examined, we found that the patients' first priority was functional abilities (ICF: body function and structure) such as using the hands and feet while the caregivers and physiotherapists prioritized self-care problems (ICF: activity and participation). The most common response to the theme 2 was "being in same health condition before the disease" (ICF: activity and participation) among the patients and caregivers and "being able to move arm and leg on the affected side" (body function and structure) among the physiotherapists. CONCLUSION: As a conclusion, problems faced by the patients, caregivers, and physiotherapists were perceived under the same ICF domain and that caregivers' and physiotherapists' priorities were the same.

Reliability and validity of the 4-meter walk test in patients with multiple sclerosis.

BACKGROUND: Walking speed is considered a vital sign of health and better functional outcomes. It is important to assess walking speed both for disease monitoring and before starting rehabilitation. The aim of this study was to examine the reliability, validity, minimal detectable change, and the ideal cutoff time for differentiating patients with multiple sclerosis (PwMS) who fall from PwMS who do not. METHODS: This study included 43 PwMS (26 female and 17 male) and 36 healthy controls (23 female and 13 male). The 4-meter walk test (4-MWT) was conducted with the 10-meter walk test (10-MWT), timed up and go (TUG) test, dynamic gait index (DGI), timed 25-foot walk (T25-FW), multiple sclerosis walking scale-12 (MSWS-12), and the expanded disability status scale (EDSS). RESULTS: Excellent test-retest reliability (ICC = 0.971) was found for the 4-MWT. The SEM value was 0.38 and MDC value was 1.05. The correlations with 4-MWT, 10-MWT, TUG, DGI, T25-FW, MSWS-12, and EDSS were found to be statistically significant (p < 0.001). PwMS had longer 4-MWT times than healthy controls, and PwMS fallers had longer 4-MWT times than non-fallers with PwMS (r between 0.668 and -0.858; p < 0.05 for all). In order to distinguish fallers from non-fallers with PwMS, a 4-MWT cutoff time of 4.14 s was shown to be optimal. CONCLUSION: The 4-MWT was found to be valid and reliable for PwMS. It is concluded that the 4-MWT is a feasible assessment method for clinical and methodological studies of PwMS with mild to moderate disability.

An investigation of upper extremity function, sleep quality, and functional independence in patients with poststroke shoulder pain: a cross-sectional study.

BACKGROUND: Poststroke shoulder pain (PSSP) is a common poststroke complication. Even though it is a common phenomenon, it is unclear how it impacts the patient's life. OBJECTIVE: To investigate the differences in upper extremity function, sleep quality, and functional independence between patients with and without PSSP. METHODS: This cross-sectional study included 63 participants with stroke (32 patients with PSSP and 31 patients without PSSP). Shoulder pain was evaluated with a Visual Analog Scale and the participants were divided into two groups as those with and without PSSP. The upper extremity function was assessed with the Disabilities of the Arm, Shoulder, and Hand Questionnaire, the Arm Motor Ability Test, and the Nine Hole Peg Test. Sleep quality was assessed with Pittsburgh Sleep Quality Index and the functional independence was assessed with the Functional Independence Measure. All data were analyzed using the program IBM SPSS Statistics 22.0. The Mann-Whitney U test was used to compare the non-normally distributed parameters, and the Chi-square test was used to compare the ordinal variables. The Spearman correlation test was used for the relationship and a linear regression test was used for regression. RESULTS: Upper extremity function decreased (p < .05), only the sleep disturbance sub-parameter of sleep quality increased (p = .01), and functional independence increased in patients with PSSP (p < .001). There was a moderate relationship between pain and upper extremity function and a fair relationship between pain and sleep quality (use of sleep medications, daytime dysfunction sub-parameters) (p < .05). CONCLUSIONS: PSSP impairs upper extremity functions, which play an important role in activities of daily living, and reduces functional independence. These results suggest that it is important to evaluate shoulder pain and examine the factors affecting pain in the rehabilitation of patients with stroke.

Investigation of the relationship between trunk position sense and balance, functional mobility, fear of falling, and disease stage in Parkinson's disease.

INTRODUCTION: Parameters related to trunk control such as balance disorders, mobility problems, and falling are frequently observed in patients with Parkinson's disease (PD). However, to provide a stable foundation for movement, trunk stability requires appropriate adequate position sense. The aim of the study was to examine the relationship between trunk position sense, balance, functional mobility, fear of falling, and disease stage in patients with PD. METHODS: The study was conducted in 41 patients with PD (16 female and 25 male). Trunk position sense was assessed with a digital inclinometer, balance with functional reach test, Berg balance scale and one-leg stand test, functional mobility with timed up and go test, fear of falling with activity-specific balance confidence scale, and disease stage with Modified Hoehn and Yahr Scale (MHYS). All patients were tested during the "on" phase following drug therapy. RESULTS: Repositioning error degree was related with MHYS, Berg balance scale, right and left one-leg stand test, forward functional reach test, timed up and go test, timed up and go test-cognitive and activity-specific balance confidence scale results in patients with PD (r = - 0.363/ - 0.609, p < 0.05 for all). CONCLUSION: It was shown in the study that trunk position sense was associated with disease stage, balance level, functional mobility, and fear of falling in patients with PD. These results suggest that trunk position sense is more important to plan effective rehabilitation program for development and protection of disease stage, balance level, functional mobility, and fear of falling in patients with PD.

Investigation of parameters related to lower extremity muscle strength and proprioception in Patients with Multiple Sclerosis: a cross-sectional study.

BACKGROUND: Patients with Multiple Sclerosis (PwMS) may experience a decline in balance, gait, and mobility as well as an increase in fear of falling (FoF) and fatigue due to weaker muscles and proprioceptive loss in their lower limbs. The study aimed to compare lower extremity muscle strength and proprioception, balance, functional mobility, gait, FoF, and fatigue between PwMS and healthy controls and to investigate the relationship between lower extremity muscle strength and proprioception and balance, functional mobility, gait, FoF, and fatigue in PwMS. METHODS: The study was completed with 35 PwMS and 35 healthy controls with matching age and gender. The 5 Repetition Sit-to Stand Test (5-STS-test), knee and ankle reposition tests (using a digital inclinometer), the Berg Balance Scale (BBS), the Timed Up and Go (TUG) test, the Dynamic Gait Index (DGI), the Falls Efficacy-International (FES-I), and the Fatigue Severity Scale (FSS) were used for evaluations. RESULTS: The 5-STS test, knee and ankle reposition tests, TUG, FES-I, and FSS Test scores were higher and BBS and DGI scores were lower in PwMS compared to healthy controls (p < 0.05). BBS, DGI, TUG, FES-I, and FSS were associated with 5-STS test and knee and ankle reposition tests except for some nondominant reposition tests in PwMS (r between 0.342 and -0.714; p < 0.05 for all). CONCLUSION: Lower extremity muscle strength and proprioception were associated with balance, functional mobility, gait, FoF, and fatigue in PwMS. These results suggested that detailed assessment of neuromuscular parameters in lower extremity function is important in determining the appropriate rehabilitation programs.

Core stability-based balance training and kinesio taping for balance, trunk control, fear of falling and walking capacity in patients with multiple sclerosis: A randomized single-blinded study.

BACKGROUND: Trunk performance-based therapies are important in the Multiple Sclerosis (MS) rehabilitation process since they have been associated with balance, trunk performance, fall prevention, and walking capacity. Kinesio taping (KT) is a popular approach that has recently been used to treat a variety of musculoskeletal and neuromuscular impairments. Therefore, the aim of this single-blind, randomized controlled study was to investigate the effects of KT combined trunk stabilization-based balance training on balance, trunk control, walking capacity, and fear of falling in patients with MS. MATERIAL AND METHODS: Thirty patients diagnosed with MS were randomly assigned to the KT group or the control group. The control group received core stability-based balance training and the KT group was treated with KT applied on global trunk muscles in addition to core stability-based balance training. Balance was measured with the Mini BESTest, trunk control with the Trunk Impairment Scale, fear of falling with the Falls Efficacy Scale and walking capacity with the 2-minute walk test. RESULTS: Balance, trunk control, fear of falling, and walking capacity of all the patients improved after treatment (p < 0.05). No superiority was found between the groups in terms of treatment efficacy (p > 0.05). CONCLUSION: In conclusion, core stability-based balance training was effective in patients with MS, and the addition of KT had no additional effect in terms of balance, trunk control, fear of falling, and walking capacity.

An Investigation of temporomandibular pain, headache, and fatigue in relation with long-term mask use during the COVID-19 pandemic period.

OBJECTIVE: To investigate the effects of long-term mask use on temporomandibular pain, headache, and fatigue during the COVID-19 pandemic period via a survey. METHODS: The survey was sent online, and symptoms associated with mask use, perception of mask discomfort, temporomandibular dysfunction, fatigue, headache, and trigger points of temporomandibular joint were evaluated. RESULTS: For the study, 909 people were screened. Head, neck, face, throat, ear, and jaw pain, cheek tension, teeth clamping, acne, mask trace, palpitation, and voice and sleep disorders were different between groups (p < 0.05). The individuals' temporomandibular dysfunction and fatigue were different between groups (p < 0.05). CONCLUSION: Long-term mask use can cause many symptoms, such as headache, jaw pain, and fatigue. Furthermore, increased mask-wearing time can trigger all these symptoms. The authors recommend relaxing breaks and exercises for neck, jaw, and face muscles along with the use of appropriate masks to minimize negative symptoms.

An investigation of biomechanics, muscle performance, and disability level of craniocervical region of individuals with temporomandibular disorder.

OBJECTIVE: To investigate biomechanics, muscle performance, and disability of the craniocervical region in temporomandibular disorder (TMD) patients and compare them with controls. METHODS: Craniocervical posture was evaluated using lateral photography and radiography. Range of motion, muscle performance, disability, and TMD severity were assessed using an inclinometer, Functional Strength Testing of Cervical Spine, Neck Disability Index, and Fonseca Anamnestic Index, respectively. RESULTS: Compared to the control group, the TMD group demonstrated higher cervical flexion angle (p=0.005) and neck disability (p<0.001) as well as lower cervical extension (p=0.040), right cervical rotation (p=0.005), left cervical rotation (p<0.001), and tragus-C7-horizontal (p=0.048) angles, and reduced muscle performances (p≤0.001). Most patients had higher than normal craniocervical angle (p<0.001). Muscle performance in each cervical motion (p<0.005) and disability (p<0.001) were associated with TMD severity in the TMD group. CONCLUSION: Biomechanics, muscle performance, and disability of craniocervical region were altered in the TMD group.

An investigation of knee position sense, balance, and dual task performance in different phases of menstrual cycle in females with multiple sclerosis: a pilot study.

BACKGROUND: Sex hormones have been thought to play an important role in disease progression and inflammatory activity in females with multiple sclerosis. The aim of this study was to investigate knee position sense, balance, and dual task performance in different phases of menstrual cycle in females with multiple sclerosis. METHODS: The study included 14 females diagnosed with MS and 13 healthy females with regular menstrual cycles who did not use oral contraceptives. The disability level was determined using the Expanded Disability Status Scale. The mental state was assessed using the Mini-Mental State Examination. Knee position sense was evaluated with an Acumar dual digital inclinometer (Acu360, Acumar, Lafayette, IN, USA). The balance was measured with the Biodex Balance System (Biodex Medical Systems, Shirley, NY, USA). Time taken to complete the Timed Up and Go test (TUG) under 3 conditions (TUG without task, TUG with counting backward from 100 by 3s or listing the names starting with the letter "A" [TUGcognitive], and TUG while carrying three glasses of water on a tray [TUGmotor]) was measured. Measurements were conducted in the early follicular, ovulation, and luteal phases. RESULTS: As a result, it was found that knee position sense, dynamic balance, and dual task performance decreased in the early follicular phase in both the group of females with multiple sclerosis and the control group (p<0.05). The change of dynamic balance and gait performance in the three phases of the menstrual cycle were different between the groups (p<0.05). CONCLUSION: As a result, it was found that knee position sense, dynamic balance, and dual task performance in females with multiple sclerosis changed throughout the menstrual cycle. The change in dynamic balance and gait performance differed from the control group during the menstrual cycle. Therefore, we think that each phase of the menstrual cycle should be taken into consideration in the follow-up of physiotherapy evaluations in females with multiple sclerosis.

Thickness, cross-sectional area, and stiffness of intrinsic foot muscles affect performance in single-leg stance balance tests in healthy sedentary young females.

The purpose of this study was to investigate the effect of thickness, cross-sectional area and stiffness of intrinsic foot muscles on performance in single-leg stance balance tasks in healthy sedentary young females. This study included a total of 40 healthy sedentary young females between the ages of 19 and 35 years. Single-leg stance balance assessments were carried out using Biodex Balance Systems (Biodex Medical Systems, Shirley, NY, USA). Performance in the single-leg stance balance tests was assessed using the overall stability index (OSI), mediolateral stability index (MLSI) and the anteroposterior stability index (APSI). Lower scores indicated better postural stability. Stiffness, thickness and cross-sectional area measurements of the abductor hallucis (AbH), flexor digitorum brevis (FDB) and flexor hallucis brevis (FHB) muscles were performed using an ultrasonography device. Larger AbH and FHB muscles were correlated with higher OSI, APSI, and MLSI (r = 0.31-0.46, p < 0.05), whereas larger FDB muscle was correlated with higher OSI and MLSI (r = 0.28-0.38, p < 0.05). Higher stiffness of the AbH and FHB muscles were correlated with lower OSI, APSI, and MLSI (r = -0.32 to 0.58, p < 0.05), but stiffness of the FDB muscle was not significantly correlated with OSI, APSI, and MLSI (r = 0.03-0.22, p Ëƒ 0.05). These results suggest that larger AbH, FDB and FHB muscles are related to reduced performance in single-leg stance balance tests, whereas higher AbH and FHB stiffness are related to better performance in single-leg stance balance tests in healthy sedentary young females.

Morphological and mechanical properties of plantar fascia and intrinsic foot muscles in individuals with and without flat foot.

PURPOSE: Many musculoskeletal disorders are associated with over-pronated foot and decreased medial longitudinal arch (MLA) height. Foot intrinsic muscles and plantar fascia (PF) are the primary structures that support MLA. An important reason for the over-pronated foot and the reduction in the MLA height may be the morphological characteristics of the foot intrinsic muscles and PF as well as changes in their mechanical properties. The aim of the present study is to investigate the morphologic structure and mechanical properties of PF, flexor hallucis brevis (FHB), flexor digitorum brevis (FDB), and abductor hallucis (AbH) muscles in individuals with flat foot and to compare the results with those of healthy individuals. METHODS: The study included 80 participants, 40 with flat foot and 40 with normal foot posture. The foot posture of the participants was assessed using the Foot Posture Index. PF, FHB, FDB, and AbH thickness and stiffness were measured with an ultrasonography device using a linear ultrasonography probe. RESULTS: Individuals with flat foot had higher AbH thickness compared to individuals with normal foot posture ( p < 0.001), whereas both groups were similar in terms of PF ( p = 0.188), FHB ( p = 0.627), and FDB ( p = 0.212) thickness. Stiffness values of the assessed tissues were similar in both groups ( p > 0.05). CONCLUSION: AbH thickness was higher in individuals with flat foot; however, PF, FHB, and FDB thickness were similar in both groups. In addition, our results suggest that foot posture is not related to the stiffness of the assessed tissues.