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Abstract Background Foot muscle weakness can produce foot deformity, pain and disability. Toe flexor and foot arch exercises focused on intrinsic foot muscle strength and functional control may mitigate the progression of foot deformity and disability. Ensuring correct exercise technique is challenging due to the specificity of muscle activation required to complete some foot exercises. Biofeedback has been used to improve adherence, muscle activity and movement patterns. We investigated the feasibility of using a novel medical device, known as “Archercise”, to provide real-time biofeedback of correct arch movement via pressure change in an inflatable bladder, and foot location adherence via sensors embedded in a footplate during four-foot exercises. Methods Thirty adults (63% female, aged 23–68 years) performed four-foot exercises twice on the Archercise sensor footplate alone and then with biofeedback. One-way repeated measures ANOVA with pairwise comparisons were computed to assess the consistency of the exercise protocol between trial 1 and trial 2 (prior to biofeedback), and the effectiveness of the Archercise biofeedback device between trial 2 and trial 3 (with biofeedback). Outcome measures were: Arch movement exercises of arch elevation and lowering speed, controlled arch elevation, controlled arch lowering, endurance of arch elevation; Foot location adherence was determined by percentage of time the great toe, fifth toe and heel contacted footplate sensors during testing and were analysed with paired sample t-tests. Participant survey comments on the use of Archercise with biofeedback were reported thematically. Results Seventeen (89%) arch movement and foot location variables were collected consistently with Archercise during the foot exercises. Archercise with biofeedback improved foot location adherence for all exercises (p = 0.003–0.008), coefficient of determination for controlled arch elevation (p

Despite the growing interest, information regarding the psychometric properties of maximal voluntary isometric toe plantarflexion force and rate of force development (RFD) is lacking. Hence, we investigate the test-retest reliability and measurement error of these outcome measurement instruments measured with a custom-built dynamometer. Twenty-six healthy adults participated in a crossed design with four sessions separated by 5–7 days. RFD was quantified using manual onset and calculating the impulse and the slope in the following time windows: 0–50 ms, 0–100 ms, 0–150 ms, 0–200 ms, 0–250 ms. We estimated the systematic bias of the mean, the intraclass correlation coefficient (ICC) and standard error of measurement (SEM) from the agreement and consistency models. The ICC and the SEM agreement for maximal voluntary isometric toe plantarflexion force along the perpendicular axis were respectively 0.87 (95%CI: 0.76, 0.93) and 27 N (22, 32), while along the resultant of the perpendicular and anterior posterior axis they were 0.85 (0.73, 0.92) and 29 N (23, 35). The results of the consistency model were similar as the estimated variance for session was closer to zero. A systematic bias of the mean between session 1 and 3 was found. For the RFD variables, the ICC agreement ranged from 0.35 to 0.65. The measurement process was found to be reliable to assess maximal voluntary isometric toe plantarflexion force but not RFD. However, a familiarization session is mandatory and these results need to be confirmed in less coordinated (e.g. aging population) individuals. • We measured maximum isometric toe plantarflexion force. • The measurement process is reliable with a small measurement error. • Rate of force development did not show equally promising properties. [ABSTRACT FROM AUTHOR]

Abstract Background Evaluating the strength of the small muscles of the foot may be useful in a variety of clinical applications but is challenging from a methodology standpoint. Previous efforts have focused primarily on the functional movement of toe flexion, but clear methodology guidelines are lacking. A novel foot doming test has also been proposed, but not fully evaluated. The purposes of the present study were to assess the repeatability and comparability of several functional foot strength assessment techniques. Methods Forty healthy volunteers were evaluated across two testing days, with a two-week doming motion practice period between them. Seven different measurements were taken using a custom toe flexion dynamometer (seated), custom doming dynamometer (standing), and a pressure mat (standing). Measurements from the doming dynamometer were evaluated for reliability (ICCs) and a learning effect (paired t-tests), while measurements from the toe flexion dynamometer and pressure mat were evaluated for reliability and comparability (correlations). Electromyography was also used to descriptively assess the extent of muscle isolation in all measurements. Results Doming showed excellent within-session reliability (ICCs > 0.944), but a clear learning effect was present, with strength (p 0.945). Seated toe flexion tests using the dynamometer were moderately correlated to standing toe flexion tests on a pressure mat (r > 0.54); however, there were some differences in muscle activity. The former may better isolate the toe flexors, while the latter appeared to be more functional for many pathologies. On the pressure mat, reciprocal motion appeared to display slightly greater forces and reliability than isolated toe flexion. Conclusions This study further refines potential methodology for foot strength testing. These devices and protocols can be duplicated in the clinic to evaluate and monitor rehabilitation progress in clinical populations associated with foot muscle weakness.

Background: Foot muscle weakness can produce foot deformity, pain and disability. Toe flexor and foot arch exercises focused on intrinsic foot muscle strength and functional control may mitigate the progression of foot deformity and disability. Ensuring correct exercise technique is challenging due to the specificity of muscle activation required to complete some foot exercises. Biofeedback has been used to improve adherence, muscle activity and movement patterns. We investigated the feasibility of using a novel medical device, known as "Archercise", to provide real-time biofeedback of correct arch movement via pressure change in an inflatable bladder, and foot location adherence via sensors embedded in a footplate during four-foot exercises. Methods: Thirty adults (63% female, aged 23–68 years) performed four-foot exercises twice on the Archercise sensor footplate alone and then with biofeedback. One-way repeated measures ANOVA with pairwise comparisons were computed to assess the consistency of the exercise protocol between trial 1 and trial 2 (prior to biofeedback), and the effectiveness of the Archercise biofeedback device between trial 2 and trial 3 (with biofeedback). Outcome measures were: Arch movement exercises of arch elevation and lowering speed, controlled arch elevation, controlled arch lowering, endurance of arch elevation; Foot location adherence was determined by percentage of time the great toe, fifth toe and heel contacted footplate sensors during testing and were analysed with paired sample t-tests. Participant survey comments on the use of Archercise with biofeedback were reported thematically. Results: Seventeen (89%) arch movement and foot location variables were collected consistently with Archercise during the foot exercises. Archercise with biofeedback improved foot location adherence for all exercises (p = 0.003–0.008), coefficient of determination for controlled arch elevation (p < 0.0001) and endurance area ratio (p = 0.001). Twenty-nine (97%) participants reported Archercise with biofeedback, helped correct exercise performance. Conclusions: Archercise is a feasible biofeedback device to assist healthy participants without foot pathologies perform foot doming exercises. Trial registration: Australian New Zealand Clinical Trials Registry (ANZCTR): 12616001559404. Registered 11 November 2016, http://www.ANZCTR.org.au/ACTRN12616001559404p.aspx [ABSTRACT FROM AUTHOR]

Abstract Background Quantifying the strength of the intrinsic foot muscles has been a challenge for clinicians and researchers. The reliable measurement of this strength is important in order to assess weakness, which may contribute to a variety of functional issues in the foot and lower leg, including plantar fasciitis and hallux valgus. This study reports 3 novel methods for measuring foot strength – doming (previously unmeasured), hallux flexion, and flexion of the lesser toes. Methods Twenty-one healthy volunteers performed the strength tests during two testing sessions which occurred one to five days apart. Each participant performed each series of strength tests (doming, hallux flexion, and lesser toe flexion) four times during the first testing session (twice with each of two raters) and two times during the second testing session (once with each rater). Intra-class correlation coefficients were calculated to test for reliability for the following comparisons: between raters during the same testing session on the same day (inter-rater, intra-day, intra-session), between raters on different days (inter-rater, inter-day, inter-session), between days for the same rater (intra-rater, inter-day, inter-session), and between sessions on the same day by the same rater (intra-rater, intra-day, inter-session). Results ICCs showed good to excellent reliability for all tests between days, raters, and sessions. Average doming strength was 99.96 ± 47.04 N. Average hallux flexion strength was 65.66 ± 24.5 N. Average lateral toe flexion was 50.96 ± 22.54 N. Conclusions These simple tests using relatively low cost equipment can be used for research or clinical purposes. If repeated testing will be conducted on the same participant, it is suggested that the same researcher or clinician perform the testing each time for optimal reliability.

Abstract 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.

Background: Evaluating the strength of the small muscles of the foot may be useful in a variety of clinical applications but is challenging from a methodology standpoint. Previous efforts have focused primarily on the functional movement of toe flexion, but clear methodology guidelines are lacking. A novel foot doming test has also been proposed, but not fully evaluated. The purposes of the present study were to assess the repeatability and comparability of several functional foot strength assessment techniques.Methods: Forty healthy volunteers were evaluated across two testing days, with a two-week doming motion practice period between them. Seven different measurements were taken using a custom toe flexion dynamometer (seated), custom doming dynamometer (standing), and a pressure mat (standing). Measurements from the doming dynamometer were evaluated for reliability (ICCs) and a learning effect (paired t-tests), while measurements from the toe flexion dynamometer and pressure mat were evaluated for reliability and comparability (correlations). Electromyography was also used to descriptively assess the extent of muscle isolation in all measurements.Results: Doming showed excellent within-session reliability (ICCs > 0.944), but a clear learning effect was present, with strength (p < 0.001) and muscle activity increasing between sessions. Both intrinsic and extrinsic muscles were engaged during this test. All toe flexion tests also showed excellent reliability (ICCs > 0.945). Seated toe flexion tests using the dynamometer were moderately correlated to standing toe flexion tests on a pressure mat (r > 0.54); however, there were some differences in muscle activity. The former may better isolate the toe flexors, while the latter appeared to be more functional for many pathologies. On the pressure mat, reciprocal motion appeared to display slightly greater forces and reliability than isolated toe flexion.Conclusions: This study further refines potential methodology for foot strength testing. These devices and protocols can be duplicated in the clinic to evaluate and monitor rehabilitation progress in clinical populations associated with foot muscle weakness. [ABSTRACT FROM AUTHOR]

Highlights What is already known • Quadratus plantae assists flexor digitorum longus in flexion of the lateral four toes and contributes to postural control. • A relationship between the evolutionary appearance of the medial head of quadratus plantae in humans and the demands of bipedalism has been suggested. • Ultrasound real-time elastography can assess the activities of regional deep-layer muscles. What this study adds • In the medial head of quadratus plantae, muscle hardness assessed by the strain ratio increased during second toe flexion movement. • In the lateral head of quadratus plantae, muscle hardness assessed by the strain ratio increased during second to fifth toe flexion movement. • Using ultrasound real-time elastography could differentiate the functions of the two heads of quadratus plantae. Abstract Quadratus plantae (QP), one of the plantar intrinsic foot muscles, assist plantarflexion of the lesser toes. QP has medial and lateral muscle heads with different anatomical structures. The two heads of this muscle may have different roles in foot function. Ultrasound real-time tissue elastography (RTE) measurements have allowed quantitative assessment of deep-layer muscle elasticity. The purpose of this study was to determine the activity of the QP in flexion movements of the lateral four toes using RTE. Thirteen healthy subjects performed maximal voluntary contractions using a hand-held dynamometer with external belt fixation for each toe flexion movement. The elasticity of the muscles were measured using RTE during rest and flexion of each toe. The strain ratio of the muscle to that in an acoustic coupler was calculated as an index of muscle elasticity. Higher strain ratio values imply lower elasticity. The strain ratio of the medial head of QP for second toe flexion (0.10 ± 0.11) was significantly stiffer than at rest (0.34 ± 0.33). The strain ratios of the lateral head of QP for flexion of the second (0.32 ± 0.19), third (0.41 ± 0.37), fourth (0.33 ± 0.26), and fifth (0.45 ± 0.39) toes were significantly stiffer than at rest (1.02 ± 0.68). These results suggest that the medial head of QP has a role in assisting second-toe flexion, and the lateral head has a role in assisting flexion of all four lateral toes. [ABSTRACT FROM AUTHOR]

Background: Quantifying the strength of the intrinsic foot muscles has been a challenge for clinicians and researchers. The reliable measurement of this strength is important in order to assess weakness, which may contribute to a variety of functional issues in the foot and lower leg, including plantar fasciitis and hallux valgus. This study reports 3 novel methods for measuring foot strength - doming (previously unmeasured), hallux flexion, and flexion of the lesser toes. Methods: Twenty-one healthy volunteers performed the strength tests during two testing sessions which occurred one to five days apart. Each participant performed each series of strength tests (doming, hallux flexion, and lesser toe flexion) four times during the first testing session (twice with each of two raters) and two times during the second testing session (once with each rater). Intra-class correlation coefficients were calculated to test for reliability for the following comparisons: between raters during the same testing session on the same day (inter-rater, intra-day, intra-session), between raters on different days (inter-rater, inter-day, inter-session), between days for the same rater (intra-rater, inter-day, inter-session), and between sessions on the same day by the same rater (intra-rater, intra-day, inter-session). Results: ICCs showed good to excellent reliability for all tests between days, raters, and sessions. Average doming strength was 99.96 ± 47.04 N. Average hallux flexion strength was 65.66 ± 24.5 N. Average lateral toe flexion was 50.96 ± 22.54 N. Conclusions: These simple tests using relatively low cost equipment can be used for research or clinical purposes. If repeated testing will be conducted on the same participant, it is suggested that the same researcher or clinician perform the testing each time for optimal reliability. [ABSTRACT FROM AUTHOR]

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.

As opposed to finger flexion response upon tapping the styloid process with absent brachioradialis reflex (inverted brachioradialis reflex), toe flexion response upon patellar percussion with absent quadriceps reflex is a quite underrecognized neurological sign, and has been reported only once in the literature. Similar to the inverted brachioradialis reflex, this sign can also be useful for neurological localization. We hereby report a patient presenting with signs and symptoms of lumbar radiculopathy in the setting of an anterior epidural mass compressing the cauda equina at L2-L4, without evidence of myelopathy. Upon examination, the patient had bilateral absent quadriceps reflexes with a right toe flexor response when the right patella was percussed. An absent quadriceps reflex with distant toe flexor response is proposed as a lower extremity equivalent of the inverted brachioradialis reflex, likely localizing to L3-L4 levels. Spindle hypersensitivity due to lack of reciprocal inhibition from antagonist muscles is hypothesized as a possible underlying mechanism. Further observations should help clarify the most common underlying etiology (radicular vs. radiculomyelopathy). Neurologists should be able to recognize this sign, as it can be helpful for neurological localization., (Copyright © 2016 Elsevier B.V. All rights reserved.)