Association between toe flexor strength and spatiotemporal gait parameters in community-dwelling older people

Differences in muscle activity of extrinsic and intrinsic foot muscles in toe grip and push-down movements of the great toe

Toe flexor strength is generated primarily by the flexor hallucis longus (FHL) of the extrinsic foot muscles (EFMs) and the plantar intrinsic foot muscles (PIFMs) of the great toe. Toe flexion methods can be broadly classified into toe grip (TG) and toe push-down (TP). Additionally, TP's interphalangeal joint (IPJ) position may influence the FHL and PIFMs activity ratios. This study aimed to elucidate the differences in the muscle activity and muscle activity ratios of the FHL and AbdH during TG, TP with IPJ flexion (TPIF), and TP with IPJ extension (TPIE). Surface electromyography and a custom-made instrument were used to measure the FHL and AbdH muscle activity during TG, TPIF, and TPIE of the great toe in 28 healthy men. The muscle activity and AbdH/FHL muscle activity ratio in the three conditions were statistically compared. The FHL activity was significantly higher during TG and TPIF than during TPIE. The AbdH muscle activity was significantly higher during TPIF and TPIE than that during TG. The AbdH/FHL muscle activity ratio was significantly higher for TPIE, TPIF, and TG in that order. This study showed that the FHL and AbdH muscle activity differed depending on the TG and TP of the great toe, and that the AbdH/FHL muscle activity ratio was different in the IPJ position. These results suggest that selecting a toe flexion method according to the target muscle when measuring and training the great toe flexor strength is important.

A 3 month nutrition and exercise program improved hallux strength among senior daycare center users in Korea: a cluster randomized controlled trial

Introduction

With a growing aging population, the focus on the health and well-being of older adults, especially in preventing falls, becomes crucial. This 3 month study, initiated in July 2022, aimed to assess the impact of a nutrition and exercise program in senior daycare centers in Chuncheon, South Korea.

Methods

A 3 month study, beginning in July 2022, included 204 older adults from 10 senior daycare centers in Chuncheon, South Korea. Randomly assigned to intervention or control groups, the intervention involved nutrition, daily toe exercises, or both. Control centers received interventions post-measurements. Pre- and post-intervention analyses used paired t-tests and multiple linear regression, assessing metrics like toe grip strength for significance. While 204 were initially enrolled, the analysis included 151 participants due to dropouts.

Results

Participants, with a mean age of 83.3 years (43.1% aged ≥ 85 years), exhibited mild to moderate cognitive impairment and multiple chronic illnesses. Health data indicated that 37.3% were obese, and the average BMI was 24.0 kg/m2. Both the intervention and control groups showed significant improvements in toe grip strength post-intervention. Specifically, the exercise-only and combined exercise-nutrition groups demonstrated significant differences in hallux strength compared to the control group after adjusting for age and gender.

Conclusion

The study showed that a basic nutrition and exercise program increased toe strength in older adults with chronic diseases, including mild cognitive impairments. This intervention holds potential to prevent muscle strength decline and reduce fall risks in older individuals. As the first of its kind in Korean senior daycare centers, it emphasizes the need for future research and standardized programs for senior daycare users.

Age-Related Reduction of Foot Intrinsic Muscle Function and the Relationship with Postural Stability in Old Adults

Introduction

The risk of falls among the elderly significantly increases, which has become a serious public health concern. Falls can not only lead to serious complications such as fractures and brain injuries but also limit their mobility function, reducing quality of life. Foot intrinsic muscles (FIMs) are an essential part of foot core stability even overall postural stability. This study aimed to investigate the effects of aging on the function of FIMs and to explore the influence of FIMs on postural control in the elderly.

Materials and Methods

56 healthy old participants (60-75 years) and 57 healthy young participants (18-29 years) joined this study. An ergoFet dynamometer was used to determine foot muscle strength (Doming, T1, T23 and T2345), and ankle muscle strength (plantarflexion and dorsiflexion). The morphology of FIMs and extrinsic foot muscle was determined using a Doppler ultrasound system, whereas the postural stability was assessed through Limits of Stability test. Independent samples t-test was used to determine the differences in strength and morphological parameters and Spearman correlation analysis was used to determine whether an association existed between muscle strength and postural stability parameters in the elderly.

Results

Compared with young adults, foot muscle strength and ankle muscle strength (Doming, T1, T23, T2345, dorsiflexion, and plantarflexion, all p <0.05) and the morphology of foot muscles (all p <0.05) were significantly reduced in the elderly. The strength of FIMs and the limit of stability (r = 0.302-0.424, all p <0.05) were significantly correlated in the elderly.

Conclusion

Compared with young adults, the weakness of strength as well as the morphological decline of the intrinsic and extrinsic foot muscles were found in the elderly. In addition, a correlation was observed between FIM's strength and postural stability in the elderly, suggesting their potential role in posture stability.

Development of a frailty prevention program including nutrition and exercise interventions for older adults in senior daycare centers in South Korea using a mixed methods research design

BACKGROUND/OBJECTIVES

The growing aging population has led to an increased utilization of senior daycare centers. This study was conducted to design a program to enhance the health of older adults in senior daycare centers in Chuncheon City, South Korea.

SUBJECTS/METHODS

The study explored the health conditions and dietary patterns of older adults in senior daycare centers. Participants included staff and older adults from senior daycare centers in Chuncheon City. A mixed methods research design was used to obtain both qualitative and quantitative data. Qualitative insights were obtained through in-depth interviews with 26 staff members and older adults, coupled with observations made at 10 senior daycare centers. The quantitative component comprised structured questionnaires and physical measurements of 204 older adults at these centers.

RESULTS

Many of the older adults relied on the meals provided by the center due to their limited cooking abilities. Dental health issues and dysphagia were common. Interviews highlighted the budgetary constraints of the centers in providing wholesome meals and the need for government support to alleviate meal expenses and enhance quality. A structured survey of older adults showed that the average age was 83.3 yrs, with an average of 2 chronic conditions per participant. Frailty analysis of the participants revealed that 56.2% were prefrail and 32.0% were frail. Almost half of the participants (47.0%) used dentures. Based on these findings, a preventive intervention program was proposed, addressing the specific needs and challenges of older adults while promoting overall well-being and preventing frailty.

CONCLUSION

Tailored health promotion strategies are crucial in senior daycare centers. Recommended interventions include staff nutrition education, improved dietary plans, and cost-effective strength training programs. These interventions aim to reduce frailty and enhance the quality of life of older adults in the community via interventions in daycare centers.

Association between Toe Pressure Strength in the Standing Position and Maximum Walking Speed in Older Adults

BACKGROUND

Considering concerns about conventional toe grip strength, we devised a method to measure toe pressure strength in the standing position, which is close to the actual motion. This study examined the association between toe pressure strength in the standing position and walking speed among older adults.

METHODS

This cross-sectional study included 150 community-dwelling older adults (81±8 years, 73% female) who participated in the physical fitness test. We analyzed the correlation between the participants' maximum walking speed and physical function. Furthermore, we performed regression analysis with the maximum walking speed as the dependent variable to examine the association with toe pressure strength in the standing position. We also examined the association between maximum walking speed and toe pressure strength in the standing position by introducing a covariate.

RESULTS

Correlation analysis revealed a significant positive correlation between maximum walking speed and toe pressure strength in the standing position, with a moderate effect size (r=0.48, p<0.001). Moreover, multiple regression analysis with covariates showed an association between maximum walking speed and toe pressure strength in the standing position (standardization factor=0.13, p<0.026).

CONCLUSION

Toe pressure strength in the standing position was associated with maximum walking speed. This finding clarifies the significance of assessing toe pressure strength in the standing position and suggests that enhanced toe pressure strength in the standing position may increase maximum walking speed.

Difference in the recruitment of intrinsic foot muscles in the elderly under static and dynamic postural conditions

Background

The effect of foot, especially intrinsic muscles, on postural control and its related mechanisms remain unclear due to the complex structure. Therefore, this study aims to investigate the activation of intrinsic foot muscles in the elderly under static and dynamic postural tasks.

Methods

Twenty-one elderly participants were included to perform different postural tests (sensory organization test (SOT), motor control test (MCT), limit of stability test (LOS), and unilateral stance test) by a NeuroCom Balance Manager System. The participants were instructed to maintain postural stability under conditions with combined different sensory inputs (vision, vestibular, and proprioception) in SOT as well as conditions with translation disturbance in MCT, and to perform an active weight-shifting tasks in LOS. During these tasks, muscle activation were simultaneously acquired from intrinsic foot muscles (abductor halluces (AbH) and flexor digitorum brevis (FDB)) and ankle muscles (anterior tibialis, medial head of gastrocnemius, lateral head of gastrocnemius, and peroneus longus). The root-mean-square amplitude of these muscles in postural tasks was calculated and normalized with the EMG activity in unilateral stance task.

Results

The activation of intrinsic foot muscles significantly differed among different SOT tasks (p < 0.001). Post-hoc tests showed that compared with that under normal condition 1 without sensory interference, EMGs increased significantly under sensory disturbance (conditions 2-6). By contrast, compared with that under the single-sensory disturbed conditions (conditions 2-4; 2 for disturbed vision, 3 for disturbed vestibular sensation, 4 for disturbed proprioception), activation was significantly greater under the dual-sensory disturbed postural tasks (conditions 5 and 6; 5 for disturbed vision and proprioception, 6 for disturbed vestibular sensation and proprioception). In MCT, EMGs of foot muscles increased significantly under different translation speeds (p < 0.001). In LOS, moderate and significant correlations were found between muscle activations and postural stability parameters (AbH, r = 0. 355-0.636, p < 0.05; FDB, r = 0.336-0.622, p < 0.05).

Conclusion

Intrinsic foot muscles play a complementary role to regulate postural stability when disturbances occur. In addition, the recruitment magnitude of intrinsic foot muscles is positively correlated with the limit of stability, indicating their contribution to increasing the limits of stability in the elderly.

Functional relationship between the foot intrinsic and extrinsic muscles in walking

The intrinsic and extrinsic muscles are considered to stabilize the foot and contribute to propulsion during walking. This study aimed to clarify the functional relationship between intrinsic and extrinsic muscles during walking. Thirteen healthy men participated in this study. The muscle activities of the intrinsic muscles (quadratus plantae and abductor hallucis), and the extrinsic muscles (flexor hallucis longus, flexor digitorum longus, and tibialis posterior) were measured using fine-wire and surface electromyography during walking. The muscle onset timing after foot contact was calculated and compared among muscles using the one-way ANOVA. The stance phase was divided into early and late braking, and early and late propulsion phases. Muscle activity among phases was compared using repeated-measures ANOVA. The onset time of the abductor hallucis was significantly earlier than those of the flexor digitorum longus and tibialis posterior. The quadratus plantae demonstrated significantly earlier onset than that of the tibialis posterior. In the late propulsion phase, the activity of extrinsic muscles decreased, whereas intrinsic muscles were continuously active. Early activation of the intrinsic muscles may stabilize the foot for efficient torque production by the extrinsic muscles. Furthermore, the intrinsic muscles may contribute to the final push-off after the deactivation of extrinsic muscles.

Association between toe pressure strength in the standing position and postural control capability in healthy adults

BACKGROUND

A method has been developed to assess toe pressure strength in the standing position, taking into account concerns about toe grip strength.

RESEARCH QUESTION

Which is more associated to postural control capability, the conventional toe grip strength or the newly devised toe pressure strength in the standing position, which is close to the actual movement?

METHODS

This study is a cross-sectional study. This study included 67 healthy adults (mean age, 19 ± 1 years; 64% male). The postural control capability was measured using the center-of-pressure shift distance in the anterior-posterior axis. Toe pressure strength in the standing position was assessed using a toe pressure measuring device to evaluate the force of pressure on the floor surface by all toes. During measurement, care is taken to ensure that the toes do not flex. However, toe grip strength in the sitting position was measured using muscle strength for toe flexion in a conventional manner. Statistical analysis was conducted by performing a correlation analysis between each of the measured items. Additionally, multiple regression analysis was used to examine the functions associated with postural control capability.

RESULT

Pearson's correlation analysis revealed that the postural control capability was correlated with toe pressure strength in the standing position (r = 0.36, p = 0.003). Multiple regression analysis demonstrated that only toe pressure strength in the standing position was significantly associated with the postural control capability, even after adjusting for covariates (standard regression coefficient: 0.42, p = 0.005).

SIGNIFICANCE

The results of this study indicated that toe pressure strength in the standing position was more strongly associated with the postural control capability in healthy adults than toe grip strength in the sitting position. It has been suggested that a rehabilitation program for toe pressure strength in the standing position would help improve postural control capability.

Foot Problems and Their Associations with Toe Grip Strength and Walking Speed in Community-Dwelling Older Individuals Using Day Services: A Cross-Sectional Study

Foot disorders in older individuals compromise balance and contribute to postural and gait instabilities, causing a decrease in the activities of daily living and quality of life. In this cross-sectional study, we analyzed the foot-related data of 160 frail older participants who attended day service centers in A prefecture in Japan to determine the prevalence of foot problems and their associations with toe grip strength and walking speed in frail older people. Multiple regression analysis was used to identify foot-related variables that correlated with toe grip strength and walking speed. The prevalence rates of skin dryness (Support level 88.2%, Care level 85.2% for men; Support level 84.9%, Care level 93% for women) and suspected and existing fungal infections in nails (Support level 94.1%, Care level 92.6% for men; Support level 98.1%, Care level 95.2% for women) were high in both sexes regardless of the level of care required. Furthermore, in both sexes, the prevalence rates of toe and arch deformities were significantly increased in the people who required care. Regression analysis revealed that some right-sided foot-related problems were significantly associated with right toe grip strength and walking speed. The decrease in toe grip strength was significantly associated with walking speed. Our study provides evidence that some specific conditions were associated with toe grip force and walking speed. This finding can contribute to future strategies to protect foot health in community-dwelling older individuals.

Comparison of toe pressure strength in the standing position and toe grip strength in association with the presence of assistance in standing up: a cross-sectional study in community-dwelling older adults

PURPOSE

We believe that toe pressure strength in the standing position, which is closer to the actual movement, is more associated with standing up in the older adults than the conventional toe grip strength. Therefore, the purpose of this study is to examine the association between toe pressure strength in the standing position and the presence of assistance in standing up in the older adults.

METHODS

Ninety-five community-dwelling older adults (82 ± 8 years old, 72% female) were included in this study. The patients were evaluated based on their need for assistance in standing up. Physical functions, including toe pressure strength in the standing position, toe grip strength, hand grip strength, knee extension strength, one-leg standing time with eyes open, and maximal walking speed, were measured.

RESULTS

When compared with and without assistance to stand up, the group requiring assistance had weaker toe pressure strength in the standing position than the group without assistance (p = 0.015, ES = 0.53). After adjusting for confounding factors, the final model revealed that toe pressure strength in the standing position was associated with the use of assistance in standing up (odds ratio 0.94 [0.88-0.99, p = 0.025]).

CONCLUSION

Toe pressure strength in the standing position was associated with the use of assistance in standing up in older adults. Improving toe pressure strength in the standing position may facilitate the ability of older adults to stand up.

Relationship between fall history and toe grip strength in older adults with knee osteoarthritis in Japan: A cross-sectional study

BACKGROUND

Knee osteoarthritis (KOA), one of the most common musculoskeletal diseases in older adults, is associated with a high incidence of falls. Similarly, toe grip strength (TGS) is associated with a history of falls in older adults; however, the relationship between TGS and falls in older adults with KOA who are at risk of falling is not known. Therefore, this study aimed to determine if TGS is associated with a history of falls in older adults with KOA.

METHODS

The study participants, older adults with KOA scheduled to undergo unilateral total knee arthroplasty (TKA), were divided into two groups: non-fall (n = 256) and fall groups (n = 74). Descriptive data, fall-related assessments, modified Fall Efficacy Scale (mFES), radiographic data, pain, and physical function including TGS were evaluated. The assessment was conducted on the day before performing TKA. Mann-Whitney and chi-squared tests were performed to compare the two groups. Multiple logistic regression analysis was performed to determine the association of each outcome with the presence or absence of falls.

RESULTS

Mann-Whitney U test revealed that the fall group had statistically significantly lower height, TGS on the affected and unaffected sides, and mFES. Multiple logistic regression analysis revealed that the incidence of fall history is associated with TGS on the affected side; the weaker the affected TGS of the KOA, the more likely the individual is to fall.

CONCLUSIONS

Our results indicate that TGS on the affected side is related to a history of falls in older adults with KOA. The significance of evaluating TGS among patients with KOA in routine clinical practice was demonstrated.

Relationship between foot morphology, muscle strength, and physical performance test in women aged 65 years and older: a cross-sectional study

BACKGROUND

Hallux valgus is a foot deformity that may affect gait, thus increasing the risk of falls among older people. We investigated the relationship between foot morphology, muscle strength, and physical performance.

METHODS

In this study, community-dwelling older people aged ≥65 years were included. A three-dimensional footprint automatic measurement apparatus was used to measure the hallux valgus angle, arch height ratio, and heel-floor angle. Furthermore, the toe flexor strength and ankle plantar flexion strength were measured. Physical performance tests included the five-repetition sit-to-stand test, one-leg standing time, maximal step length, functional reach test, and 5-m fastest walking time (walking time). The relationship between the hallux valgus angle and foot morphology and muscle strength was examined. In addition, factors affecting physical performance testing were assessed. Two-group comparisons, correlation, and multiple comparisons were used for statistical analyses.

RESULTS

Of the 133 women (age 77.7 ± 6.2 years), 57 had hallux valgus and 76 had no hallux valgus. There was a significant difference in the arch height ratio and heel-floor angle between women with and without hallux valgus (p < 0.001). A correlation was found between the hallux valgus angle and the heel-floor angle (r = 0.468, p < 0.001) and arch height ratio (r = - 0.337, p < 0.001), respectively. Multiple regression analysis showed that the hallux valgus angle was related to functional reach (β = - 0.162, p = 0.042), and toe flexor strength was related to five-repetition sit-to-stand (β = - 0.182, p = 0.036), maximal step length (β = 0.328, p < 0.001), and walking time (β = - 0.219, p = 0.006).

CONCLUSIONS

A relationship was found between the hallux valgus angle, arch height rate, and inward inclination angle of the calcaneus. Functional reach was predicted based on the hallux valgus angle, whereas the five-repetition sit-to-stand, maximal step length, and walking time were predicted based on toe flexor strength. Hallux valgus predicted not only the forefoot but also the foot morphology and was related to physical performance. From the perspective of motor function and fall prevention, efforts should be made to better understand and prevent the onset and progression of hallux valgus.

Effects of Insole with Toe-Grip Bar on Barefoot Balance and Walking Function in Patients with Parkinson's Disease: A Randomized Controlled Trial

The maintenance and improvement of balance and walking function in patients with Parkinson’s disease (PD) is essential. Toe dysfunction in patients with PD is related to balance and walking. Recently, insoles have been developed to improve toe function, but their effects on the physical functions of patients with PD remain unclear. In this randomized controlled study, we investigated the effects of insoles with a toe-grip bar on balance and walking function in such patients. Twenty-nine patients with PD in Hoehn and Yahr stages II−IV were randomly assigned to an intervention or control group. Patients in the intervention and control groups wore shoes having insoles with and without a toe-grip bar for 4 weeks, respectively. The center of gravity sway of standing posture (total trajectory length, envelope area, and maximum anterior−posterior center of pressure [AP-COP] distance) and walking parameters at normal and fast speeds were measured pre- and post-intervention in the rehabilitation room. All measurements were performed with the participants being barefoot. The maximum AP-COP distance and step length of the fast-walking condition were significantly improved in the intervention compared to the control group (p < 0.05). Thus, insoles with a toe-grip bar may improve balance and walking function in patients with PD.

Associations between the size of individual plantar intrinsic and extrinsic foot muscles and toe flexor strength

Background

The size of the plantar intrinsic and extrinsic foot muscles has been shown to be associated with toe flexor strength (TFS). Previous studies adopted the size of limited plantar intrinsic foot muscles or a compartment containing several muscles as an independent variable for TFS. Among the plantar intrinsic and extrinsic foot muscles, therefore, it is unclear which muscle(s) primarily contributes to TFS production. The present study aimed to clarify this subject.

Methods

In 17 young adult men, a series of anatomical cross-sectional area of individual plantar intrinsic and extrinsic foot muscles was obtained along the foot length and the lower leg length, respectively, using magnetic resonance imaging. Maximal anatomical cross-sectional area (ACSA_max) and muscle volume (MV) for each constituent muscle of the plantar intrinsic foot muscles (flexor hallucis brevis; flexor digitorum brevis, FDB; abductor hallucis; adductor hallucis oblique head, ADDH-OH; adductor hallucis transverse head, ADDH-TH; abductor digiti minimi; quadratus plantae) and extrinsic foot muscles (flexor hallucis longus; flexor digitorum longus) were measured. TFS was measured with a toe grip dynamometry.

Results

TFS was significantly associated with the ACSA_max for each of the ADDH-OH (r = 0.674, p = 0.003), ADDH-TH (r = 0.523, p = 0.031), and FDB (r = 0.492, p = 0.045), and the MV of the ADDH-OH (r = 0.582, p = 0.014). As for the ADDH-OH, the correlation coefficient with TFS was not statistically different between ACSA_max and MV (p = 0.189). Stepwise multiple linear regression analysis indicated that ACSA_max and MV of the ADDH-OH alone explained 42 and 29%, respectively, of the variance in TFS.

Conclusion

The ADDH-OH is the primary contributor to TFS production among the plantar intrinsic and extrinsic foot muscles as the result of the stepwise multiple linear regression analysis.

A new simpler approach to measure the strength of toe plantar flexion requiring no mechanical restraint with a light-weight device

Conventionally, the strength of toe plantar flexion (STPF) is measured in a seated position, in which not only the target toe joints but also the knee and particularly ankle joints, are usually restrained. We have developed an approach for the measurement of STPF which does not involve restraint and considers the interactions of adjacent joints of the lower extremities. This study aimed to evaluate this new approach and comparing with the seated approach. A thin, light-weight, rigid plate was attached to the sole of the foot in order to immobilize the toe area. Participants were 13 healthy young women (mean age: 24 ± 4 years). For measurement of STPF with the new approach, participants were instructed to stand, raise the device-wearing leg slightly, plantar flex the ankle, and push the sensor sheet with the toes to exert STPF. The sensor sheet of the F-scan II system was inserted between the foot sole and the plate. For measurement with the seated approach, participants were instructed to sit and push the sensor with the toes. They were required to maintain the hip, knee, and ankle joints at 90°. The mean values of maximum STPF of the 13 participants obtained with each approach were compared. There was no significant difference in mean value of maximum STPF when the two approaches were compared (new: 59 ± 23 N, seated: 47 ± 33 N). The coefficient of variation of maximum STPF was smaller for data obtained with the new approach (new: 39%, seated: 70%). Our simple approach enables measurement of STPF without the need for the restraints that are required for the conventional seated approach. These results suggest that the new approach is a valid method for measurement of STPF.

Differences in toe flexor strength and foot morphology between wheelchair dependent and ambulant older people in long-term care: a cross-sectional study

BACKGROUND

Hallux valgus, lesser toe deformity, and muscle weakness of the toe flexors contribute to falls in older people. This study aimed to examine the differences in toe flexor strength and foot morphology in older people requiring long-term care due to changes in the way they mobilize in everyday life.

METHODS

This study included 84 people aged ≥70 years without motor paralysis who underwent rehabilitation. They were divided into those who could mobilize without a wheelchair (walking group, n = 54) and those who used a wheelchair to mobilize (wheelchair group, n = 30). The presence or absence of diseases was confirmed, and hand grip strength, toe flexor strength, and foot morphology using the foot printer were measured. The presence of diseases, hand grip strength, toe flexor strength, and foot morphology were compared between the two groups. Multiple logistic analysis was performed with wheelchair dependence as the dichotomous outcome variable, and the percentages of each strength measure observed in the wheelchair group to the average hand grip and toe flexor strength measures in the walking group were compared.

RESULTS

No significant between-group difference in foot morphology was found. The factors related to the differences in ways of ambulating in daily life were history of fracture, heart disease, and toe flexor strength. After comparing the muscle strength of the wheelchair group with the mean values of the walking group, we found that the toe flexor strength was significantly lower than the hand grip strength.

CONCLUSIONS

Older people who used a wheelchair to mobilize have significantly less toe flexor strength than those who do not despite no significant difference in foot morphology. Use of a wheelchair is associated with a reduction in toe flexor strength.

The correlation between toe flexor strength and performance-based measures of physical fitness in the elderly

[Purpose] To examine the correlation between toe flexor strength (TFS) and physical fitness performance measurements and their gender differences in the elderly. [Participants and Methods] Japanese males (n=50) and females (n=121), aged 65–88 years, participated in this study. We measured TFS, handgrip strength (HGS), knee extensor strength (KES), sit-and-reach distance (SR), and functional reach (FR). [Results] The female participants had significantly lower TFS, KES, and HGS than the male participants; however, the female participants had a significantly higher SR than that the male participants. FR was not significantly different between males and females. In males, TFS was significantly correlated with HGS, KES, SR, and FR. In females, TFS had correlations with HGS, KES, and FR; however, no correlation with SR was found. We could observe these correlations even after adjustment for age and body weight. [Conclusion] Elderly male had higher TFS than elderly females. In addition, TFS was correlated with all the physical fitness measurements in the male participants and all the measurements except for SR in the female participants. Gender and aging may explain the inconsistent results between SR and other physical fitness performance measurements.

Differences in Electromyographic Activities and Spatiotemporal Gait Parameters between General and Developed Insoles with a Toe-Grip Bar

The present study was aimed at comparing the muscle activities and gait parameters between the toe-grip bar insoles and general insoles during walking using randomized crossover design. Twelve healthy men participated in this study. Temporal and spatial gait parameters and electromyography (EMG) results were concurrently collected while the subjects walked along an 8 m walkway with the developed and general insoles. Developed insoles provide a three-dimensional mesh structure at the toe portion and a convex bulging structure (toe-grip bar) near the center of the proximal phalanx of the first to fifth toe. The linear mixed model was used to estimate the toe-grip bar insole effect. The results showed that there were no sequence or period effects for any of the examined parameters. During the stance phase, those wearing the developed insoles had significantly higher %IEMG for the TA, GM, and GL than those wearing the general insoles (TA: 5.03%IEMG, p = 0.005; GM: 4.65%IEMG, p = 0.046; and GL: 6.50%IEMG, p = 0.008). During the swing phase, those wearing the developed insoles had significantly higher activity for only the TA compared to those wearing the general insoles (5.54%IEMG, p = 0.011). With respect to gait parameters, those wearing the developed insoles had greater step length (2.81 cm, p = 0.038), longer stance time (0.03 s, p = 0.001), and shorter swing time (−0.02 s, p = 0.003) compared to those wearing the general insoles. The results suggest that walking with toe-grip bar insoles contributes to increased crural muscle activity and step length.

Toe flexor strength is associated with mobility in older adults with pronated and supinated feet but not with neutral feet

Background

Older adults are known to have more pronated foot posture and decreased toe flexor strength (TFS), as well as decreased mobility in daily life compared to young adults. Although foot posture is reported to be an influential factor for walking biomechanics in young adults, there is less information on this subject in older adults. Age-related reduction in TFS is shown to be associated with impairments of functional performance, but it is poorly understood whether foot posture influences the relationships between TFS and functional performances. Therefore, the present study aimed to elucidate this concern by examining older women.

Methods

Seventy community-dwelling older women (76.8 ± 4.4 years) voluntarily participated in this study. Foot posture was evaluated by the 6-item foot posture index (FPI). Based on the FPI score, participants were allocated to pronated, neutral, or supinated group (n = 33, 26, and 11, respectively). TFS was assessed using a toe grip dynamometer in a seated position. Scores of 30-s chair stand, timed up-and-go, 5-m comfortable-speed walking, and static balance tests were determined to evaluate functional performances. Pearson’s correlation coefficients were computed to examine the relationships between TFS and functional performances in each group.

Results

TFS positively correlated with comfortable walking speed in the pronated (r = 0.37, p = 0.03) and supinated (r = 0.76, p < 0.001) groups, but not in the neutral group (r = 0.17, p = 0.42). For the two significant relationships, an analysis of covariance showed that there was no significant difference between the pronated and supinated groups in the slopes of the regression lines, suggesting a similar relative contribution of TFS to comfortable walking speed between the two groups. In addition, TFS tended to negatively correlate with timed up-and-go time in the pronated (r = − 0.32, p = 0.07) and supinated (r = − 0.56, p = 0.08) groups, and positively correlate with 30-s chair stand score in the pronated group (r = 0.31, p = 0.08).

Conclusions

The present study indicates that TFS would be associated with mobility, walking performance in particular, in older women with pronated and supinated feet but not with neutral feet.

Correlation between functional ability, toe flexor strength, and plantar pressure of hallux valgus in young female adults: a cross-sectional study

Background

The prevalence of hallux valgus (HV) increases with age in females. Several studies have investigated the relationship between foot problems, including HV, and falls in older individuals. This study aimed to examine whether HV causes a decline in functional activity in young females and also evaluate the relationship between HV angle, functional activity, toe flexor strength, and plantar pressure.

Methods

We assessed 94 females (mean age, 19.6 ± 1.3 years; mean body mass index, 21.2 ± 2.0 kg/m²) not currently receiving treatment for lower limb disease. HV angle was determined using their footprint. Functional reach (FR) and maximum step length (MSL), toe flexor strength, and plantar pressure were measured. Plantar pressure was measured during walking. We also calculated FR and the pressure in eight regions (first toe, second through fifth toes, first metatarsal, second through fourth metatarsals, fifth metatarsal, midfoot, medial heel, and lateral heel).

Results

There were 39 and 55 participants in the HV and no HV groups, respectively. FR and MSL did not differ significantly between the HV and no HV groups. Toe flexor strength was significantly different between the HV and no HV groups (26.69 ± 9.68 vs. 32.19 ± 8.55, respectively) (p = 0.002, β = 0.206). During walking, plantar pressure was significantly lower in the second through fifth toes in the HV group (p = 0.005, β = 0.187). During FR, plantar pressure was significantly greater in the first metatarsal in the HV group (p = 0.016, β = 0.338). HV angle was negatively correlated with toe flexor strength (r = − 0.315, p = 0.002, β = 0.121) and plantar pressure during walking in the second through fifth toes (r = − 0.362, p < 0.001, β = 0.047), and positively correlated with plantar pressure during FR in the first metatarsal (r = 0.308, p = 0.002, β = 0.137). Toe flexor strength was negatively correlated with plantar pressure during FR in the second through fourth metatarsals (r = − 0.318, p = 0.002, β = 0.115), and there was a positive correlation with MSL (r = 0.330, p = 0.001, β = 0.092).

Conclusions

This study confirmed that HV reduces toe flexor strength and affects forefoot pressure during walking and FR in young females. Moreover, the toe flexor strength affects MSL. Efforts to prevent the onset and deterioration of HV from a young age might help reduce the risk of falling when older.

Association Between Toe Flexor Strength and Activity Levels in Community-Dwelling Japanese Older Women

This study aimed to explore the relationship between toe flexor strength and the daily activity levels in 56 Japanese older women aged between 70 and 88 years. The activity levels were measured as the average number of steps/day using a pedometer and the life space assessment (LSA) scores. The Mann-Whitney U test was used to compare toe flexor muscle strength and the LSA scores between those with fewer than and more than 6,000 steps/day. Spearman's correlation coefficient was used to investigate the relationship between toe grip strength according to age and each variable. The LSA scores were significantly higher in the group with >6,000 steps/day (β = 0.188, p < .05). A correlation was found between the number of steps/day and toe flexor strength (r = .424, β = 0.419, p < .05) and the LSA scores (r = .417, β = 0.435, p < .05) in the participants in their 80s. Increasing the number of steps/day may benefit women in their 80s.

VALIDITY OF A FBG-BASED SMART SOCK SYSTEM FOR MEASURING TOE GRIP FUNCTION IN HUMAN FOOT

This study developed a smart sock system using optical fiber technology to measure the toe grip function of individual toes. The system comprised Fiber Bragg grating (FBG) sensors incorporated into a sock garment for measuring maximum toe flexion displacements. Calibration equation of each FBG sensor was determined from 3D motion capture system on 10 female subjects. The validity of the smart sock system was checked by comparing maximum toe flexion displacement against the gold standard of 3D motion capture. The root mean squared error was 0.95 (0.57) cm across 10 toes. The magnitude of toe displacement and error was similar between the left and right feet. In conclusion, the FBG-based smart sock system can successfully measure maximum toe flexion displacements of individual toes simultaneously. This system can be developed to support the evaluation of toe grip function in clinical and field settings.

Effects of Long-Term Use of Insoles with a Toe-Grip Bar on the Balance, Walking, and Running of Preschool Children: A Randomized Controlled Trial

This randomized controlled study is aimed at investigating the effects of long-term use of insoles with a toe-grip bar on the balance, walking, and running of preschool children. Fifty-two preschool children were randomly assigned to an intervention group or control group. Children included in the intervention group wore shoes with insoles that had a toe-grip bar, and those in the control group wore shoes with regular insoles without a toe-grip bar for 4 weeks while they were at school. The center of gravity sway (total trajectory length and envelope area), walking parameters (walking speed, cadence, stride length, step length, stance time, and swing time), and time to run 25 m were measured before and after the intervention. The 25 m running time of the intervention group was significantly improved after the intervention (F = 5.66; p < 0.05). This study suggests that insoles with a toe-grip bar may contribute to improvements in the running of preschool children.

Effect of foot care interventions for older adults using day care services

AIM

This study explored the prevalence of foot problems among older adults and the effectiveness of foot care interventions for improving toe-gap force and foot flexibility. Foot problems are very common among people aged 65 years and older. However, the effects of foot care interventions on components underlying these issues (i.e., toe-gap force and foot flexibility) are unclear.

DESIGN

This was a quasi-experimental study.

METHODS

Eighteen older adults were divided into three groups: medical foot care intervention, combined intervention and control group. The combined intervention group received medical foot care, foot hygiene and five-toed socks. Toe-gap force and foot flexibility were measured.

RESULTS

The most common foot problems were hallux valgus, toe deformities, nail discoloration and thickness and dryness. Significant differences in right foot toe-gap force were observed between the combined intervention and control groups. There were no significant differences in foot flexibility between groups.

The effects of toe grip training on physical performance and cognitive function of nursing home residents

Background

Toe grip-related training requires individuals to actively exercise muscles that are not frequently used; therefore, it may improve not only toe grip strength but also cognitive function. The purpose of this study was to examine the effects of toe grip-related training on predictors of physical performance and cognitive function in nursing home residents.

Methods

A total of 35 nursing home residents (35 left and 35 right feet; mean age, 82.1 ± 7.9 years) were included in this study. The participants were divided into two groups: a training group and a control group. The Mini-Mental State Examination (MMSE) was used to assess the cognitive function of the participants, and the Fall Risk Index (FRI) was used to evaluate the risk of falls. Toe grip-related physical function was also assessed. Baseline endpoints were evaluated and the effects of toe grip-related training were examined following a 12-week training intervention.

Results

The training group showed significant improvements in MMSE score, FRI score, toe grip strength, and the toe skill (TS) test; however, the control group did not show these changes. The training group showed significant increases in Δ MMSE, Δ toe grip strength, and Δ TS (right foot) than the control group. Stepwise regression analysis revealed that Δ toe grip strength is an independent factor of Δ MMSE.

Conclusions

Toe grip training improves not only toe grip strength itself, but also cognitive function. Furthermore, change in toe grip strength was an independent factor of change in MMSE in those populations.

Trial registration

UMIN, UMIN000027437. Registered on 26 May 2017.

Poor toe flexor strength, but not handgrip strength, is associated with the prevalence of diabetes mellitus in middle-aged males

Previous studies suggested that reduced muscular strength was one of the potential predictor of prevalence of diabetes mellitus. The purpose of this study was to investigate the association between toe flexor strength (TFS) and handgrip strength (HGS) and the prevalence of diabetes mellitus. Cross-sectional analysis was conducted using data from 1,390 Japanese males (35-59 years). TFS and HGS were measured and medical examinations undertaken. The prevalence of diabetes mellitus was defined as fasting blood glucose ≥126 mg/dL, glycated hemoglobin ≥6.5% (48 mmol/mol), and/or current use of anti-diabetes mellitus drugs. A total of 114 participants had diabetes mellitus. TFS in participants with diabetes mellitus was significantly lower than that in persons not suffering from diabetes mellitus but HGS was not. Odds ratio (OR) and 95% confidence interval (CI) per 1-standard deviation-increase in muscular strength measurements for the prevalence of diabetes mellitus were obtained using a multiple logistic regression model. Prevalence of diabetes mellitus was inversely related to TFS (OR 0.769, 95% CI 0.614-0.963), TFS/body mass (BM) (0.696, 0.545-0.889) and TFS/body mass index (BMI) (0.690, 0.539-0.882) after adjustment of covariates. Such associations were not observed in HGS (OR 0.976, 95% CI 0.773-1.232), HGS/BM (0.868, 0.666-1.133) or HGS/BMI (0.826, 0.642-1.062). These results suggested that poor TFS was associated with an increased prevalence of diabetes mellitus independent of visceral fat accumulation, but HGS was not, in middle-aged males. TFS may be a better marker for the prevalence of diabetes mellitus than HGS.

Gender difference in factors affecting the medial longitudinal arch height of the foot in healthy young adults

[Purpose] Medial longitudinal arch (MLA) height is associated with various injuries and diseases and gender differences, if any. This study aimed to examine factors affecting the MLA height associated with gender differences in healthy subjects with no orthopedic disorders. [Subjects and Methods] This study included 36 healthy adults (19 males, 17 females; mean age, 21.8 ± 3.6 years; body mass index, 21.1 ± 2.0 kg/m²). Their height, body weight, foot length, muscle strength of the tibialis posterior muscle (TPM), toe-gripping strength, hallux valgus angle, inversion microdactylia angle, angle of leg-heel alignment, femoro-tibial angle, and navicular height were measured. Correlation between the ratio of arch height and other measurement parameters was examined. [Results] In females, the ratio of arch height was significantly positively correlated with muscle strength of the TPM and toe-gripping strength and negatively correlated with the hallux valgus angle and the leg-heel alignment, whereas in males, only a positive correlation between the ratio of arch height and muscle strength of the TPM was observed. [Conclusion] These results reveal that etiological mechanisms determining MLA height are different between males and females. Overall, the present results indicate that further studies identifying causes of MLA height variation must include gender-based analysis.

Effect of Insoles with a Toe-Grip Bar on Toe Function and Standing Balance in Healthy Young Women: A Randomized Controlled Trial

Objective

The aim of this randomized controlled study was to investigate the effects of insoles with a toe-grip bar on toe function and standing balance in healthy young women.

Methods

Thirty female subjects were randomly assigned to an intervention group or a control group. The intervention group wore shoes with insoles with a toe-grip bar. The control group wore shoes with general insoles. Both groups wore the shoes for 4 weeks, 5 times per week, 9 hours per day. Toe-grip strength, toe flexibility, static balance (total trajectory length and envelope area of the center of pressure), and dynamic balance (functional reach test) were measured before and after the intervention.

Results

Significant interactions were observed for toe-grip strength and toe flexibility (F = 12.53, p < 0.01; F = 5.84, p < 0.05, resp.), with significant improvement in the intervention group compared with that in the control group. Post hoc comparisons revealed that both groups showed significant improvement in toe-grip strength (p < 0.01 and p < 0.05, resp.), with higher benefits observed for the intervention group (p < 0.01). Conversely, no significant interaction was observed in the total trajectory length, envelope area, and functional reach test.

Conclusions

This study suggests that insoles with a toe-grip bar contribute to improvements in toe-grip strength and toe flexibility in healthy young women.

The association between toe grip strength and osteoarthritis of the knee in Japanese women: A multicenter cross-sectional study

We evaluated the relationship between altered foot function and knee osteoarthritis through a specific comparison of toe grip strength in older women with and without knee osteoarthritis. Participants were 120 women with knee osteoarthritis (OA group) and 108 healthy community-dwelling women with no history of knee pain and lower limb surgery (control group). The following factors and outcome variables were included in our analysis: measured toe grip strength, isometric knee extension strength, the timed Up-and-Go, and the WOMAC scale. Between-group differences were compared using unpaired t-tests for descriptive characteristics and outcome measures. Pearson’s correlation coefficients between toe grip strength and age, body mass index, and other outcome measures were calculated. Multiple logistic regression analysis was used to evaluate the independence of toe grip strength and knee osteoarthritis. Compared to the control group, participants in the OA group were older, heavier, and had a higher body mass index. Toe grip strength and isometric knee extension strength were lower and the timed Up-and-Go longer for the OA group than the control group. Toe grip strength was correlated with age negatively and isometric knee extension strength positively in the OA group and to age and the timed Up-and-Go negatively, and isometric knee extension strength positively in the control group. Multiple logistic regression analysis revealed that body mass index, isometric knee extensor strength, and toe grip strength were independently associated with knee osteoarthritis. Our findings indicate a probable association between altered forefoot function and the incidence or progression of knee osteoarthritis. Increasing toe grip strength might provide a practical intervention for patients with knee osteoarthritis.

Age-related reduction and independent predictors of toe flexor strength in middle-aged men

Background

Toe flexor muscles play an important role in posture and locomotion, and poor toe flexor strength is a risk factor for falls. In this cross-sectional study, we estimated the age-related change in toe flexor strength and compared it with that of handgrip strength. Independent factors predicting toe flexor and handgrip strength were also determined.

Methods

A total of 1401 male (aged 35–59 years) study participants were divided into five groups according to their chronological age; 35–39, 40–44, 45–49, 50–54, and 55–59 years. Toe flexor and handgrip strength, anthropometry, and resting blood pressure were measured. Fasting blood samples were collected to measure blood glucose, triglycerides, high- and low-density lipoprotein-cholesterols, and albumin. A self-administered lifestyle questionnaire was conducted.

Results

Decline in absolute toe flexor and handgrip strength began in the age groups 50–55 and 55–59 years, respectively. In comparison to the mean values of the youngest group, relative toe flexor strength (87.0 ± 26.6%) was significantly lower than handgrip strength (94.4 ± 13.1%) for the oldest group. Multiple regression analyses showed that independent factors predicting both toe flexor and handgrip strength were lean body mass, age, serum albumin, drinking habit, and fat mass. Additionally, fasting blood glucose, diastolic blood pressure, sleeping time and exercise habit were predicting factors of toe flexor strength but not of handgrip strength.

Conclusions

Age-related reduction in toe flexor strength was earlier and greater than handgrip strength, and toe flexor strength reflects body composition and metabolic status.

Anthropometric, functional and foot trajectory determinants of stride length in self-reliant community-dwelling elderly persons in Talca, Chile

Abstract Objective: To analyze anthropometric, muscle performance and foot trajectory determinants of stride length (SL) during walking at a comfortable pace among self-reliant community-dwelling elderly persons in Talca, Chile. Method: A total of 63 self-reliant elderly persons participated in this observational and cross-sectional study. They were characterized by the anthropometric measures of mass, height and body mass index. Dorsiflexor muscle strength performance (DF-MS) and rate of force development were quantified. Finally, the elderly persons were asked to walk comfortably around a 40 meter elliptical circuit, using determined SL and maximum foot clearance (MaxFC) and minimum foot clearance (MFC) trajectory parameters. The SL determinants were evaluated by calculating the coefficient of determination (r2) considering a level of significance of p≤0.05. Results: The anthropometric variables demonstrated significant correlations (r>0.41) with the explanation of SL remaining incipient (r2<0.20). Muscle performance, meanwhile, was significantly correlated (r>0.52), with DF-MS standing out (r2=0.342). MaxFC represented a significant explanation for the data (r2=0.396), while the low correlation of MFC was not significant (r=0.24, r2=0.058). Conclusion: MaxFC and DF-MS are determinants of SL in self-reliant elderly Chileans. It is proposed that gait parameters could be normalized in accordance with trajectory and muscular performance.

Early reduction in toe flexor strength is associated with physical activity in elderly men

[Purpose] To compare the toe flexor, hand grip and knee extensor strengths of young and elderly men, and to examine the association between toe flexor strength and physical activity or inactivity levels. [Subjects and Methods] Young (n=155, 18–23 years) and elderly (n=60, 65–88 years) men participated in this study. Toe flexor, hand grip, and knee extensor strength were measured. Physical activity (time spent standing/walking per day) and inactivity (time spent sitting per day) were assessed using a self-administered questionnaire. [Results] Toe flexor, hand grip, and knee extensor strength of the elderly men were significantly lower than those of the young men. Standing/walking and sitting times of the elderly men were lower than those of the young men. Toe flexor strength correlated with hand grip and knee extensor strength in both groups. In elderly men, toe flexor strength correlated with standing/walking time. In comparison to the young men’s mean values, toe flexor strength was significantly lower than knee extensor and hand grip strength in the elderly group. [Conclusion] The results suggest that age-related reduction in toe flexor strength is greater than those of hand grip and knee extensor strengths. An early loss of toe flexor strength is likely associated with reduced physical activity in elderly men.

Foot-related pain and disability and spatiotemporal parameters of gait during self-selected and fast walking speeds in people with gout: A two-arm cross sectional study

OBJECTIVES

To examine gait parameters in people with gout during different walking speeds while adjusting for body mass index (BMI) and foot-pain, and to determine the relationship between gait parameters and foot-pain and disability.

METHOD

Gait parameters were measured using the GAITRite™ walkway in 20 gout participants and 20 age- and sex-matched controls during self-selected and fast walking speeds. Foot-pain and disability was measured using the Manchester Foot Pain and Disability Index (MFPDI) which contains four domains relating to function, physical appearance, pain and work/leisure.

RESULTS

At the self-selected speed, gout participants demonstrated increased step time (p=0.017), and stance time (p=0.012), and reduced velocity (p=0.031) and cadence (p=0.013). At the fast speed, gout participants demonstrated increased step time (p=0.007), swing time (p=0.005) and stance time (p=0.019) and reduced velocity (p=0.036) and cadence (p=0.009). For participants with gout, step length was correlated with total MFPDI (r=-0.62, p=0.008), function (r=-0.65, p=0.005) and physical appearance (r=-0.50, p=0.041); stride length was correlated with total MFPDI (r=-0.62, p=0.008), function (r=-0.65, p=0.005) and physical appearance (r=-0.50, p=0.041); and velocity was correlated with total MFPDI (r=-0.60, p=0.011), function (r=-0.63, p=0.007) and work/leisure (r=-0.53, p=0.030).

CONCLUSION

Gait patterns exhibited by people with gout are different from controls during both self-selected and fast walking speeds, even after adjusting for BMI and foot-pain. Additionally, gait parameters were strongly correlated with patient-reported functional limitation, physical appearance and work/leisure difficulties, while pain did not significantly influence gait in people with gout.

Intra-rater reliability of hallux flexor strength measures using the Nintendo Wii Balance Board

Background

The purpose of this study was to investigate the intra-rater reliability of a new method in combination with the Nintendo Wii Balance Board (NWBB) to measure the strength of hallux flexor muscle.

Methods

Thirty healthy individuals (age: 34.9 ± 12.9 years, height: 170.4 ± 10.5 cm, weight: 69.3 ± 15.3 kg, female = 15) participated. Repeated testing was completed within 7 days. Participants performed strength testing in sitting using a wooden platform in combination with the NWBB. This new method was set up to selectively recruit an intrinsic muscle of the foot, specifically the flexor hallucis brevis muscle. Statistical analysis was performed using intra-class coefficients and ordinary least product analysis. To estimate measurement error, standard error of measurement (SEM), minimal detectable change (MDC) and percentage error were calculated.

Results

Results indicate excellent intra-rater reliability (ICC = 0.982, CI = 0.96-0.99) with an absence of systematic bias. SEM, MDC and percentage error value were 0.5, 1.4 and 12 % respectively.

Conclusions

This study demonstrates that a new method in combination with the NWBB application is reliable to measure hallux flexor strength and has potential to be used for future research and clinical application.