Synergic control of the minimum toe clearance in young and older adults during foot swing on treadmill walking in different speeds.

BACKGROUND: The vertical toe position at minimum toe clearance (MTC) in the swing phase is critical for walking safety. Consequently, the joints involved should be strictly controlled and coordinated to stabilize the foot at MTC. The uncontrolled manifold (UCM) hypothesis framework has been used to determine the existence of synergies that stabilize relevant performance variables during walking. However, no study investigated the presence of a multi-joint synergy stabilizing the foot position at MTC and the effects of age and walking speed on this synergy. RESEARCH QUESTIONS: Is there a multi-joint synergy stabilizing MTC during treadmill walking? Does it depend on the persons' age and walking speed? METHODS: Kinematic data from 23 young and 15 older adults were analyzed using the UCM approach. The participants walked on a treadmill at three speeds: slow, self-selected, and fast. The sagittal and frontal joint angles from the swing and stance legs and pelvis obliquity were used as motor elements and the vertical toe position at MTC was the performance variable. The variances in the joint space that affected (VORT, 'bad' variance) and did not affect (VUCM, 'good' variance) the toe position at MTC and the synergy index (ΔV) were computed. RESULTS: The ΔV>0 was revealed for all subjects. Walking speed did not affect ΔV in older adults, whereas ΔV reduced with speed in young adults. ΔV was higher for older than for young adults at self-selected and fast speeds, owing to a lower VORT in the older group. SIGNIFICANCE: The vertical toe position at MTC was stabilized by a strong multi-joint synergy. In older adults, this synergy was stronger, as they were better at limiting VORT than young adults. Reduced VORT in older adults could be caused by more constrained walking, which may be associated with anxiety due to walking on a treadmill.

Effects of walking speeds on lower extremity kinematic synergy in toe vertical position control: An experimental study.

BACKGROUND: This study aimed to investigate whether lower limb joints mutually compensate for each other, resulting in motor synergy that suppresses toe vertical position fluctuation, and whether walking speeds affect lower limb synergy. METHODS: Seventeen male university students walked at slow (0.85 ±â€…0.04 m/s), medium (1.43 ±â€…0.05 m/s) and fast (1.99 ±â€…0.06 m/s) speeds on a 15-m walkway while lower limb kinematic data were collected. Uncontrolled manifold analysis was used to quantify the strength of synergy. Two-way (speed × phase) repeated-measures analysis of variance was used to analyze all dependent variables. RESULTS: A significant speed-by-phase interaction was observed in the synergy index (SI) (P  < .001). At slow walking speeds, subjects had greater SI during mid-swing (P  < .001), while at fast walking speeds, they had greater SI during early-swing (P  < .001). During the entire swing phase, fast walking exhibited lower SI values than medium (P  = .005) and slow walking (P  = .027). CONCLUSION: Kinematic synergy plays a crucial role in controlling toe vertical position during the swing phase, and fast walking exhibits less synergy than medium and slow walking. These findings contribute to a better understanding of the role of kinematic synergy in gait stability and have implications for the development of interventions aimed at improving gait stability and reducing the risk of falls.

A toe-inspired rigid-flexible coupling wheel design method for improving the terrain adaptability of a sewer robot.

The human toe, characterized by its rigid-flexible structure comprising hard bones and flexible joints, facilitates adaptive and stable movement across varied terrains. In this paper, we utilized a motion capture system to study the adaptive adjustments of toe joints when encountering obstacles. Inspired by the mechanics of toe joints, we proposed a novel design method for a rigid-flexible coupled wheel. The wheel comprises multiple elements: a rigid skeleton, supporting toes, connecting shafts, torsion springs, soft tendons, and damping pads. The torsion springs connect the rigid frame to the supporting toes, enabling them to adapt to uneven terrains and pipes with different diameters. The design was validated through kinematic and dynamic modeling, rigid-flexible coupled dynamics simulation, and stress analysis. Different stiffness coefficients of torsion springs were compared for optimal wheel design. Then, the wheel was applied to a sewer robot, and its performance was evaluated and compared with a pneumatic rubber tire in various experiments, including movement on flat surfaces, overcoming small obstacles, adaptability tests in different terrains, and active driving force tests in dry and wet pipelines. The results prove that the designed wheel showed better stability and anti-slip properties than conventional tires, making it suitable for diverse applications such as pipeline robots, desert vehicles, and lunar rovers.

Relationship between the strength of the ankle and toe muscles and functional stability in young, healthy adults.

This study investigates the relationship between ankle and toe strength and functional stability in young adults, with a sample comprising sixteen females and fourteen males. The research employed force platform data to determine the center of foot pressure (COP) and calculated the forward functional stability index (FFSI) through foot anthropometric measurements. Strength measurements of toe and ankle muscles, during maximal isometric flexion and extension, were conducted using force transducers. Notable positive correlations were found between toe flexor strength and FFSI (left flexor: r = 0.4, right flexor: r = 0.38, p < 0.05), not influenced by foot anthropometry. Contrarily, no significant correlation was observed between ankle muscle strength and FFSI, despite a positive correlation with the COP range. The moderate correlation coefficients suggest that while toe flexor strength is a contributing factor to functional stability, it does not solely determine functional stability. These findings highlight the critical role of muscle strength in maintaining functional stability, particularly during forward movements and emphasize the utility of FFSI alongside traditional COP measures in balance assessment. It is recommended to employ a multifaceted approach is required in balance training programs.

The Effects of Pointe Shoes on Ballet Dancers' Biomechanics, Muscle Activity, Movement and Symptoms: A Scoping Review.

Introduction: Dancing en pointe requires ballet dancers to stand on the tips of their toes while wearing a structured pointe shoe. Understanding the effect of pointe shoes on ballet dancers' biomechanics, function, symptoms and skin health is essential to guide shoe development and ultimately improve dancer performance. Therefore, the purpose of this scoping review was to map the evidence and identify knowledge gaps related to the effect of wearing pointe shoes on professional and recreational ballet dancers. Method: A scoping review was conducted by searching 6 electronic databases and the International Association for Dance Medicine and Science Bibliography. Results: Thirty-five studies were grouped into 5 categories: pointe shoe factors (eg, toe box and shank, pointe shoe status; 9 studies), shoe types (eg, flat shoes vs demi pointe vs pointe; 10 studies), ballet movements (11 studies), symptoms (5 studies), and intrinsic dancer factors (eg, foot type/toe length; 7 studies). Studies were published between 1979 and 2023, with 72% (n = 23) published between 2006 and 2020. Most (86%) of the studies were cross-sectional. Most studies explored biomechanical outcomes and the most common data collection device was force plates (19 studies). Overall, there was an insufficient volume of evidence for specific research aims. Significant gaps in knowledge exist regarding functional and performance-based outcomes, injury outcomes including exploration of factors such as shoe age/usage, and pointe shoe treatment factors. Conclusions: Currently the field of research suffers from threats to ecological validity, with many study methods not reflecting ballet-specific demands or environments. The impact of pointe shoes on ballet dancers is a developing research area, and this scoping review can help guide future research decisions. Studies need to target the knowledge gaps and employ rigorous ecologically valid study designs and ensure that findings inform shoe design and dancer education to minimize injury and maximize comfort and performance.

Predictive simulations identify potential neuromuscular contributors to idiopathic toe walking.

BACKGROUND: Most cases of toe walking in children are idiopathic. We used pathology-specific neuromusculoskeletal predictive simulations to identify potential underlying neural and muscular mechanisms contributing to idiopathic toe walking. METHODS: A musculotendon contracture was added to the ankle plantarflexors of a generic musculoskeletal model to represent a pathology-specific contracture model, matching the reduced ankle dorsiflexion range-of-motion in a cohort of children with idiopathic toe walking. This model was employed in a forward dynamic simulation controlled by reflexes and supraspinal drive, governed by a multi-objective cost function to predict gait patterns with the contracture model. We validated the predicted gait using experimental gait data from children with idiopathic toe walking with ankle contracture, by calculating the root mean square errors averaged over all biomechanical variables. FINDINGS: A predictive simulation with the pathology-specific model with contracture approached experimental ITW data (root mean square error = 1.37SD). Gastrocnemius activation was doubled from typical gait simulations, but lacked a peak in early stance as present in electromyography. This synthesised idiopathic toe walking was more costly for all cost function criteria than typical gait simulation. Also, it employed a different neural control strategy, with increased length- and velocity-based reflex gains to the plantarflexors in early stance and swing than typical gait simulations. INTERPRETATION: The simulations provide insights into how a musculotendon contracture combined with altered neural control could contribute to idiopathic toe walking. Insights into these neuromuscular mechanisms could guide future computational and experimental studies to gain improved insight into the cause of idiopathic toe walking.

Three-dimensional motion of the toes with simulated contraction of individual toe flexors and extensors: A cadaver study.

BACKGROUND: The primary motion of the toes is flexion and extension. The motion results from activity of multiple muscles, and toe disorders may result from muscle dysfunction. The relationships of specific muscles related to toe function is underreported. The purpose of this study was to quantitatively evaluate three-dimensional toe motion resulting from specific muscle contraction using cadavers. METHODS: Three-dimensional joint movements of the 1st, 2nd, and 5th toe were produced by applying traction of individual muscles using six Thiel-embalmed cadaver legs. The traction increments were 3 mm, 6 mm, and 9 mm, during which the angle of the distal bone with respect to the proximal bone of each toe joint was measured using a magnetic tracking system. RESULTS: As tendon traction distance increased, the angular measure of the distal bone with respect to the proximal bone at each toe joint increased linearly and three-dimensionally. The flexor hallucis brevis significantly pronated and abducted the 1st toe compared to the extensor hallucis longus and brevis. The flexor digitorum brevis significantly supinated and adducted the 2nd toe compared to the flexor digitorum longus and quadratus plantae, while the extensor digitorum brevis demonstrated significant pronation and abduction compared to the extensor digitorum longus. CONCLUSIONS: Three intrinsic muscles produced significant toe motion in frontal and horizontal planes. Our results revealed that there was a proportional relationship between tendon excursion and joint angle, and an antagonistic relationship of muscles acting on the toes. These results can be considered regarding pathogenesis of toe disorders or deformity and regarding treatment such as exercise therapy or tendon transfer. LEVEL OF EVIDENCE: V, cadaveric study.

Functional Bandaging in Children with Idiopathic Toe-Walking.

BACKGROUND: Idiopathic toe-walking (ITW) is a persistent gait pattern with no known etiology characterized as premature heel rise or no heel contact. We investigated the effects of functional bandaging in children with ITW on heel contact during stance phase and on gait quality. METHODS: Nineteen children aged 4 to 16 years with ITW and ten age-matched healthy children were included in the study. Elastic adhesive bandages were applied to children with ITW to assist with dorsiflexion. Before bandaging (T0) and immediately (T1) and 1 week (T2) after initial bandaging, the initial contact, loading response, and midstance subphases of gait were analyzed using light pressure sensors and the Edinburgh Visual Gait Score (EVGS). Ten age-matched children with typical gait participated for comparison in T0. The data were analyzed with Friedman and Wilcoxon signed rank tests for within-group comparisons and Mann-Whitney U tests for between-group comparisons. RESULTS: In T0, for the ITW group, no heel contact was observed during stance. In T1, all of the participants achieved heel contact at initial contact and loading response and 56.8% at midstance. In T2, all of the heels continued contact at initial contact and loading response and 54.3% at midstance. The EVGS significantly improved. The Friedman test showed that there were noteworthy improvements between T0-T1 and T0-T2 in video-based observational gait analysis and EVGSs (P < .001), although no difference was found between T1-T2 in video-based observational gait analysis (P = .913) and EVGSs (P = .450). CONCLUSIONS: In children with ITW, dorsiflexion assistive functional bandaging was an effective tool to help achieve heel contact on the ground and improve walking quality for a short period after application. Further studies with longer follow-up and larger sample sizes are required to confirm the long-term therapeutic effects of this promising functional bandaging.

Effects of diabetes mellitus on step length and minimum toe clearance adaptation.

BACKGROUND: Adaptive gait involves the ability to adjust the leading foot in response to the requirement of dynamic environments during walking. Accurate adjustments of the minimum toe clearance (MTC) height and step length can prevent older people from falling when walking and responding to hazards. Although older people with diabetes fall more frequently than healthy older adults, no previous studies have quantified their adaptive gait abilities. This study aimed to investigate the effects of diabetes mellitus on step length and MTC height adjustments using a non-immersive virtual-reality system. METHODS: Sixteen young adults (26 ± 5 years, 7 females), 16 healthy older adults (68 ± 5 years, 6 females), and 16 older adults with diabetes (70 ± 5 years, 6 females) completed adaptability tests while walking on a treadmill. A computer system visualised a continuous real-time signal of absolute step length and MTC on a monitor. Each person responded to four discrete participant-specific step length and MTC visual targets that were presented on the same signal. Tasks were to match the peaks of interest on each signal to presented targets. Targets were 10% longer or shorter than the mean baseline step length, and 2.5 cm, and 3.5 cm higher than the mean baseline MTC. When a target was displayed, it remained unchanged for 10 consecutive foot displacement adaptation attempts. Then, the target was removed and a new target or the same target was present after 10 consecutive steps and remained for 10 steps. Each target was randomly presented three times (3 × 10). Step length and MTC height adjustments in response to targets were measured and compared among groups. RESULTS: Mean preferred walking speeds were not different among groups significantly when no targets were presented on the monitor in baseline walking. However, when participants walked on a treadmill while attempting to match step lengths or MTC heights to displayed targets on the monitor, the group with diabetes had reduced step length and MTC adjustments compared with other groups significantly. They showed greater errors (differences between their step lengths/MTC heights and presented targets) on the monitor. CONCLUSIONS: This study quantified reduced abilities for older individuals with diabetes to adjust both step length and MTC in response to stimuli compared to healthy older counterparts. Reduced step length and MTC height adjustments can increase falls in at risk populations. The presented virtual-reality system has merits for assessing and training step and MTC adaptation.

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.

Central versus peripheral mechanisms of cold-induced vasodilation: a study in the fingers and toes of people with paraplegia.

PURPOSE: This study examined physiological and perceptual parameters related to cold-induced vasodilation (CIVD) in the fingers and toes of people with paraplegia and compared them with responses observed in able-bodied individuals. METHODS: Seven participants with paraplegia and seven able-bodied individuals participated in a randomized matched-controlled study involving left-hand and -foot immersion in cold water (8 ± 1 °C) for 40 min during exposure to cool (16 ± 1 °C), thermoneutral (23 ± 1 °C), and hot (34 ± 1 °C) ambient conditions. RESULTS: Similar CIVD occurrence was observed in the fingers in the two groups. In toes, three of the seven participants with paraplegia revealed CIVDs: one in cool, two in thermoneutral, and three in hot conditions. No able-bodied participants revealed CIVDs in cool and thermoneutral conditions, while four revealed CIVDs in hot conditions. The toe CIVDs of paraplegic participants were counterintuitive in several respects: they were more frequent in cool and thermoneutral conditions (compared to the able-bodied participants), emerged in these conditions despite lower core and skin temperatures of these participants, and were evident only in cases of thoracic level lesions (instead of lesions at lower spinal levels). CONCLUSION: Our findings demonstrated considerable inter-individual variability in CIVD responses in both the paraplegic and able-bodied groups. While we observed vasodilatory responses in the toes of participants with paraplegia that technically fulfilled the criteria for CIVD, it is unlikely that they reflect the CIVD phenomenon observed in able-bodied individuals. Taken together, our findings favor the contribution of central over peripheral factors in relation to the origin and/or control of CIVD.

Modification of the locomotor pattern when deviating from the characteristic heel-to-toe rolling pattern during walking.

PURPOSE: Humans are amongst few animals that step first on the heel, and then roll on the ball of the foot and toes. While this heel-to-toe rolling pattern has been shown to render an energetic advantage during walking, the effect of different foot contact strategies, on the neuromuscular control of adult walking gaits has received less attention. We hypothesised that deviating from heel-to-toe rolling pattern affects the energy transduction and weight acceptance and re-propulsive phases in gait along with the modification of spinal motor activity. METHODS: Ten subjects walked on a treadmill normally, then placed their feet flat on the ground at each step and finally walked on the balls of the feet. RESULTS: Our results show that when participants deviate from heel-to-toe rolling pattern strategy, the mechanical work increases on average 85% higher (F = 15.5; p < 0.001), mainly linked to a lack of propulsion at late stance. This modification of the mechanical power is related to a differential involvement of lumbar and sacral segment activation. Particularly, the delay between the major bursts of activation is on average 65% smaller, as compared to normal walking (F = 43.2; p < 0.001). CONCLUSION: Similar results are observable in walking plantigrade animals, but also at the onset of independent stepping in toddlers, where the heel-to-toe rolling pattern is not yet established. These indications seem to bring arguments to the fact that the rolling of the foot during human locomotion has evolved to optimise gait, following selective pressures from the evolution of bipedal posture.

Effect of postural differences on the activation of intrinsic foot muscles during ramp-up toe flexion in young men.

BACKGROUND: Intrinsic foot muscle exercises are used in clinical and sports practice to improve performance. Force generation during toe flexion is greater in the standing posture than in the sitting posture; nonetheless, the mechanism underlying the activation of intrinsic foot muscles during force generation and whether there exists a difference between these two postures still remain unclear. RESEARCH QUESTION: Are the activities of intrinsic foot muscles affected by standing and sitting postures during gradual force generation? METHODS: Seventeen men participated in the laboratory based cross-sectional study. Each participant performed a force ramp-up toe flexion task from 0% to 80% of the maximal toe flexor strength (MTFS) in sitting and standing postures. High-density surface electromyography signals obtained during the task were determined by calculating the root mean square (RMS). Additionally, modified entropy and coefficient of variation (CoV) were calculated at 20-80 % MTFS for each 10 % MTFS. RESULTS: The RMS between the two postures indicated an interaction effect (p < 0.01). Post-hoc analyses revealed that intrinsic foot muscle activity during the ramp-up task was significantly higher in the standing posture than in the sitting posture at 60 % MTFS (67.53 ± 15.91 vs 54.64 ± 19.28 % maximal voluntary contraction [MVC], p = 0.03), 70 % MTFS (78.11 ± 12.93 vs 63.28 ± 18.65 % MVC, p = 0.01), and 80 % MTFS (81.78 ± 14.07 vs 66.90 ± 20.32 % MVC, p = 0.02). In the standing posture, the modified entropy at 80 % MTFS was lower than that at 20 % MTFS (p = 0.03), and the CoV at 80 % MTFS was higher than that at 20 % MTFS (p = 0.03). SIGNIFICANCE: These results indicated that posture selection is important for high-intensity exercises of the intrinsic foot muscles, such as resistance training. Thus, improving performance related to toe flexor strength might be more effective when conducted under adequate weight-bearing situations, such as in the standing posture.

Development of the Idiopathic Toe Walking Outcome (iTWO) proforma: A modified delphi study and online parent survey for measurement consensus.

BACKGROUND: Idiopathic toe walking (ITW) is an exclusionary diagnosis given when children toe walk without a medical reason. Treatment effectiveness studies rarely collect data other than ankle range of motion or presence of toe walking. RESEARCH QUESTION: To develop a set of outcome measures identified by health professionals for use when providing treatment with children who have ITW, to understand if parents agreed with this set, and if parents believed they could perform these measures in clinician absence. METHODS: Study 1 developed consensus and agreement on outcome measures for children receiving treatment for ITW through the modified Delphi technique with 10 expert health professionals. Parents of children who toe walked were invited to participate in an online survey for the second study, in which they were asked to rate the importance of these measures and if they believed they may be able to collect the data about their child without the health professional being present. RESULTS: Ten health professionals developed nine questions and assessments through consensus and agreement over the three rounds. There were 34 parents providing information about satisfaction with toe walking assessments and treatments. Of these, 27 provide detailed responses about the outcome questions and assessments. The majority (91 % of 24 parents) in support of the outcome measures identified by experts. Parents expressed a willingness to self-complete questions or be taught assessments to monitor their child's progress. SIGNIFICANCE: Use of these clinically based measures may enable consistent data collection regardless of the setting and provide the foundation for large data pooling in future treatment research.

Assessing sensory processing differences in children with idiopathic toe walking: A pilot study.

Idiopathic toe-walking (ITW) refers to persistent walking without heel contact for unknown reasons. An underexplored area is the relationship of sensory processing to ITW. This study presents methods to assess sensory differences in individuals with ITW and summarizes results from a pilot testing of the measures. This pilot study included nine children and one young adult with ITW. Ten age-matched controls were recruited to provide a comparison group when norms were not available in the literature. The measures included in this study were as follows: sensory questionnaires; electrodermal activity response to sensory stimuli; monofilaments; biothesiometer; gait on different surfaces; NeuroCom® SMART Balance Master® Sensory Organization Test and Adaptation Test; and ankle position matching. All study procedures were completed in about 3 hours. Children as young as 4 years were able to complete the measures. We observed overall differences in sensory processing, specifically, higher Sensory Processing Measure scores (p = .011), higher resting electrodermal activity (p = .012), increases in heel-toe walking on novel surfaces (p = .034), and more falls with balance perturbation (p = .007) in individuals with ITW. A subset of individuals also showed tactile hyposensitivity (5 out of 10 in the ITW group) and poor equilibrium scores in the Sensory Organization Test (4 out of 9 in the ITW group, 1 unable to complete the test). Our results confirmed the heterogeneity in the etiology of ITW. We propose that further testing in sensory modulation, tactile processing, and vestibular processing is needed to fully explore the impact of sensory processing on children with ITW.

Increased toe flexor strength does not relate to altered postural sway during static upright standing after 12 weeks of multicomponent exercise training.

This study investigated whether an increase in toe flexor strength influenced postural control during static upright standing after 12 weeks of multicomponent exercise training in healthy young men. Twelve men (18-23 yrs) performed multicomponent exercise 3 days per week for 12 weeks. Twelve additional age-matched men were recruited for the untrained control group. The multicomponent exercise training consisted of strengthening and balance exercises for the foot and leg muscles. Toe flexor strength, foot arch height and postural control were assessed before, during, and after exercise training. Postural control was evaluated using the path of the centre of pressure, which was obtained with a force plate under three standing conditions: double-leg standing with eyes open, double-leg standing with eyes closed, and single-leg standing with eyes open. The dominant leg was used for single-leg standing. After exercise training, toe flexor strength increased by approximately 32% (p < 0.01), whereas the foot arch height did not change. The centre of pressure variables during double-leg standing did not change after exercise training; however, these variables decreased during single-leg standing. None of the variables in the control group changed after exercise training. The relative increase in toe flexor strength was not correlated with the relative improvement in the centre of pressure variables during single-leg standing after 12 weeks of exercise training (total length, r = 0.1734; mean velocity, r = 0.1734; sway area, r = -0.1372). These findings suggest that increased toe flexor strength has no significant effect on static postural control ability after exercise training in young men.HighlightsTwelve weeks of multicomponent exercise training aimed at strengthening foot and leg muscles increased toe flexor strength.Multicomponent exercise training did not alter postural stability during double-leg standing, but improved postural stability during single-leg standing.Increased toe flexor strength did not relate to altered postural stability during static upright standings after 12 weeks of exercise training.

Two-point discrimination responses in children with idiopathic toe walking: A feasibility fMRI study.

Idiopathic toe walking (ITW) is a diagnosis given to children who walk with an absence or limitation of heel strike in the contact phase of the gait cycle, that are otherwise typically developing. There is emerging evidence that this gait pattern may occur in children who experience tactile sensory processing challenges. This feasibility study aimed to determine if children were able to respond to a sensory stimulus during a fMRI. Children aged between 8-16 years of age, with and without idiopathic toe walking were recruited from general public advertising. Participants were required to perform a two-point discrimination test (task block) and press a button without being tested (control block) during an fMRI using a standard block design. Activation differences were examined in the left frontal pole, left supramarginal gyrus, left parahippocampal gyrus, left paracingulate gyrus and the right superior temporal. Five children were in the typically developing (TD) group and three were in the ITW group. There were between-group activation differences in the decision-making block compared to the control block in the left frontal lobe, parahippocampal gyrus and the right superior temporal gyrus. There was greater variation in activation in the left supramarginal gyrus and the left paracingulate gyrus in the ITW group compared to the typically developing group. Based on this study a future sample size of 15 children per group will be required to detect an adequate effect across chosen regions of interest Conducting fMRI using two-point discrimination testing on this population is feasible. Further research is required with larger population sizes to determine if brain activation patterns during the sensory input decision-making process are different in this population.

Toe Grip strength declines earlier than hand grip strength and knee extension strength in community-dwelling older men: a cross sectional study.

BACKGROUND: The aim of this study is to examine the age-related changes in the toe grip strength and its differences from hand grip strength and knee extension strength using cross-sectional data. METHODS: Of participants aged 65 years over who underwent health checkups for lifestyle-related diseases in 2018, 307 men and women met the criteria. Toe grip strength, hand grip strength, and knee extension strength were also measured as optional tests. The participants were divided into five groups categorized by every 5 years of age (Group 65-85). The data were analyzed with multiple comparisons using the linear mixed multilevel model to examine the following categories: association between age and muscle strength, differences in the pattern of change, and gender, using the 65-69 years group as a reference. RESULTS: In men, there were interaction effects between the factors of age and muscle, but in women there were not. Toe grip strength was significantly lower in Group 70, 75, 80, and 85 in men, lower in Group 85 than in 65 in women. Hand grip strength was significantly lower in Group 85 than in 65 in both men and women. There was no significant difference in knee extension strength among the age groups for both men and women. CONCLUSIONS: The decline in toe grip strength may occur earlier and in a different pattern from hand grip strength and knee extension strength in men.

Investigation of the Relationship Between the Morphology of the Toe Flexor Muscles in Ballet Dancers and the Postural Stability During Standing on Demi-Pointe: A Cross-Sectional Study.

INTRODUCTION: This study investigated how toe flexor muscles are related to postural stability in 11 ballet dancers and 12 non-dancers.
Methods: Toe flexor strength (TFS), cross-sectional areas (CSA) of the abductor hallucis, flexor hallucis brevis, flexor digitorum brevis, flexor hallucis longus (FHL), and flexor digitorum longus, and center of pressure (COP) displacement during single-leg demi-pointe were measured. Correlations between toe flexor strength and COP displacement and between CSA and COP displacement within each group were calculated using Pearson's correlation coefficient or Spearman's correlation coefficient.
Results: The dancers showed smaller COP displacement than the non-dancers (p < 0.05). Toe flexor strength in dancers was moderately negatively correlated with COP displacement in the anterior-pos- terior direction (r = -0.54, p < 0.01) and total COP displacement (r = -0.57, p < 0.01). Only the CSA of the FHL in dancers exhibited a significant negative correlation with COP displacement in the anterior-posterior direction (r = -0.42, p < 0.05) and total COP displacement (r = -0.52, p < 0.01).
Conclusion: The present study found a relationship between the toe flexor strength and COP displacement and CSA of toe flexor muscles and COP displacement during one-legged demi-pointe standing. These results suggest that the development of the toe flexor muscles may be involved in the balance control of dancers.