Effects of intrinsic foot muscle strengthening on the medial longitudinal arch mobility and function: A systematic review.

OBJECTIVE: To Investigate the effects of intrinsic foot muscle (IFM) strengthening on foot's medial longitudinal arch (MLA) mobility and function in healthy individuals. We also identified exercise type and resistance training characteristics (series and repetitions). METHODS: Eight databases were searched, between October 2020 and February 2021 and updated in May 2021. We included randomized controlled trials involving IFM strengthening exercises compared with controls (no exercise or exercises not involving isolated intrinsic foot muscle strengthening). Methodological quality of the studies was assessed using PEDro scale and Cochrane Risk of Bias tool. Quality of evidence was evaluated using GRADE model (Grading of Recommendations, Assessment, Development and Evaluations). RESULTS: Four randomized controlled trials (RCT) were included. IFM strengthening did not change MLA mobility in the short-term (4 weeks); however, it promoted medium-term effects (8 weeks - low quality of evidence). IFM exercises improved function in the short and medium-term (low quality of evidence). Most studies used the short-foot exercise and the toe-towel curl exercise with contractions of 5 s and load progression from sitting to standing. CONCLUSION: IFM strengthening exercises change MLA mobility in the medium-term (8 weeks) and improve the dynamic balance of healthy individuals in short- (4 weeks) and medium-terms.

Attenuation of foot pressure during running on four different surfaces: asphalt, concrete, rubber, and natural grass.

The practice of running has consistently increased worldwide, and with it, related lower limb injuries. The type of running surface has been associated with running injury etiology, in addition other factors, such as the relationship between the amount and intensity of training. There is still controversy in the literature regarding the biomechanical effects of different types of running surfaces on foot-floor interaction. The aim of this study was to investigate the influence of running on asphalt, concrete, natural grass, and rubber on in-shoe pressure patterns in adult recreational runners. Forty-seven adult recreational runners ran twice for 40 m on all four different surfaces at 12 ± 5% km · h(-1). Peak pressure, pressure-time integral, and contact time were recorded by Pedar X insoles. Asphalt and concrete were similar for all plantar variables and pressure zones. Running on grass produced peak pressures 9.3% to 16.6% lower (P < 0.001) than the other surfaces in the rearfoot and 4.7% to 12.3% (P < 0.05) lower in the forefoot. The contact time on rubber was greater than on concrete for the rearfoot and midfoot. The behaviour of rubber was similar to that obtained for the rigid surfaces - concrete and asphalt - possibly because of its time of usage (five years). Running on natural grass attenuates in-shoe plantar pressures in recreational runners. If a runner controls the amount and intensity of practice, running on grass may reduce the total stress on the musculoskeletal system compared with the total musculoskeletal stress when running on more rigid surfaces, such as asphalt and concrete.

Identification of muscle fatigue by tracking facial expressions.

Resistance training (RT) is performed at distinct levels of intensity from the beginning to the end of exercise sets, increasing the sensation of effort as the exercise progress to more vigorous levels, commonly leading to changes on the facial expression of RT practitioners. The objective of this study is to evaluate changes in facial expressions using the Facial Action Coding System(FACS) and the activation of facial muscles by surface electromyography(sEMG) at two different levels of effort during resistance exercise and to investigate the correlation between facial expression and exercise intensity and fatigue. Eleven healthy male participants [23±6years; 1.77±6 m; 78±10kg] performed a set of arm curl exercise at 50% and 85% 1RM until muscle fatigue. The Surface electromyography (sEMG activity was recorded simultaneously in areas of the epicranius muscle (EM) and zygomatic major muscle (ZM). Facial expression was recorded and blindly scored by five experienced examiners. Scores (0-5) were based on the level of activity of the ZM (lip corner puller-Action Unit 12-FACS) during exercise. Facial expression and sEMG data were obtained during the exercise at the first repetition and at muscle failure. The root mean square (RMS) of the sEMG amplitude of the EM was significantly increased between the first and last repetition (50%1RM:p = 0.002,d = 1.75; and 85%1RM:p = 0.002,d = 1.54). The RMS values for the ZM were significantly increased between the first and last repetition (50%1RM:p<0.001,d = 2.67; 85%1RM:p<0.001,d = 0.50). The RMS values for the ZM were also increased in 85%1RM compared to values obtained from 50%1RM (p = 0.001,d = 1.12) at the first repetition. AU12 scores and RMS values were not statistically different between 85%1RM and 50%1RM at the last repetition. Furthermore, there was a strong correlation (r = 0.61;p = 0.045) between AU12 scores and the sEMG peak for the ZM. In conclusion, changes in facial expression may be directly correlated with different resistance exercise intensities and fatigue.

Assessing experience in the deliberate practice of running using a fuzzy decision-support system.

The judgement of skill experience and its levels is ambiguous though it is crucial for decision-making in sport sciences studies. We developed a fuzzy decision support system to classify experience of non-elite distance runners. Two Mamdani subsystems were developed based on expert running coaches' knowledge. In the first subsystem, the linguistic variables of training frequency and volume were combined and the output defined the quality of running practice. The second subsystem yielded the level of running experience from the combination of the first subsystem output with the number of competitions and practice time. The model results were highly consistent with the judgment of three expert running coaches (r>0.88, p<0.001) and also with five other expert running coaches (r>0.86, p<0.001). From the expert's knowledge and the fuzzy model, running experience is beyond the so-called "10-year rule" and depends not only on practice time, but on the quality of practice (training volume and frequency) and participation in competitions. The fuzzy rule-based model was very reliable, valid, deals with the marked ambiguities inherent in the judgment of experience and has potential applications in research, sports training, and clinical settings.

Differences in lifestyle, physical performance and quality of life between frail and robust Brazilian community-dwelling elderly women.

AIM: To investigate the lifestyles, physical performance and quality of life (QOL) of frail and robust Brazilian community-dwelling older women, and to identify risk factors for frailty. METHODS: Frailty was assessed using the Kihon Checklist. Lifestyles were assessed using a questionnaire. Physical performance was assessed by measuring walking speeds, performance on the one-leg stand test and the five-times chair stand test and handgrip strength. QOL was assessed using the Short Form-8 questionnaire. Participants were divided into frail and robust groups based on their total Kihon Checklist scores. RESULTS: A total of 109 participants (age 70.8 ± 6.87 years) were included in this study (robust n = 85, frail n = 24). Differences in living structures (P < 0.001), financial satisfaction (P = 0.004) and the frequencies with which participants leave the house (P < 0.001) were found between groups. The frail group had more fallers (P = 0.047), and lower engagement in physical activity (P = 0.044), lower body mass indices (P = 0.043) and poorer nutritional status (P = 0.002), whereas robust older people showed better physical performance (walking speed P < 0.001, one-leg stand P = 0.021, handgrip strength P = 0.002) and higher QOL scores (general health P = 0.005, role-physical P = 0.013, bodily pain P = 0.002, vitality P = 0.001, social functioning P = 0.001, role-emotional P = 0.008). Multivariate regression analysis identified a slow usual walking speed and bodily pain as risk factors for frailty. CONCLUSIONS: Frail participants had higher indices for being housebound, and having financial dissatisfaction, a sedentary lifestyle, falls, and malnutrition. Furthermore, they showed poorer physical performance and QOL. An early, well-focused approach is crucial, especially for older adults who walk slowly and have bodily pain to preserve health and QOL. Geriatr Gerontol Int 2016; 16: 829-835.

Dynamic Patterns of Forces and Loading Rate in Runners with Unilateral Plantar Fasciitis: A Cross-Sectional Study.

AIM/HYPOTHESIS: The etiology of plantar fasciitis (PF) has been related to several risk factors, but the magnitude of the plantar load is the most commonly described factor. Although PF is the third most-common injury in runners, only two studies have investigated this factor in runners, and their results are still inconclusive regarding the injury stage. OBJECTIVE: Analyze and compare the plantar loads and vertical loading rate during running of runners in the acute stage of PF to those in the chronic stage of the injury in relation to healthy runners. METHODS: Forty-five runners with unilateral PF (30 acute and 15 chronic) and 30 healthy control runners were evaluated while running at 12 km/h for 40 meters wearing standardized running shoes and Pedar-X insoles. The contact area and time, maximum force, and force-time integral over the rearfoot, midfoot, and forefoot were recorded and the loading rate (20-80% of the first vertical peak) was calculated. Groups were compared by ANOVAs (p<0.05). RESULTS: Maximum force and force-time integral over the rearfoot and the loading rate was higher in runners with PF (acute and chronic) compared with controls (p<0.01). Runners with PF in the acute stage showed lower loading rate and maximum force over the rearfoot compared to runners in the chronic stage (p<0.01). CONCLUSION: Runners with PF showed different dynamic patterns of plantar loads during running over the rearfoot area depending on the injury stage (acute or chronic). In the acute stage of PF, runners presented lower loading rate and forces over the rearfoot, possibly due to dynamic mechanisms related to pain protection of the calcaneal area.

The effects of plantar fasciitis and pain on plantar pressure distribution of recreational runners.

BACKGROUND: Plantar fasciitis is the third most frequent injury in runners. Despite its high prevalence, its pathogenesis remains inconclusive. The literature reports overload as the basic mechanism for its development. However, the way that these plantar loads are distributed on the foot surface of runners with plantar fasciitis and the effects of pain on this mechanical factor has not yet been investigated. Therefore, the aim of this study was to evaluate and compare the plantar pressure distributions during running in runners with symptom or history of plantar fasciitis and runners without the disease. METHODS: Forty-five recreational runners with plantar fasciitis (30 symptomatic and 15 with previous history of the disease) and 60 runners without plantar fasciitis (control group) were evaluated. Pain was assessed by a visual analogue scale. All runners were evaluated by means of the Pedar system insoles during running forty meters at a speed of 12(5%) km/h, using standard sport footwear. Two-way ANOVAS were employed to investigate the main and interaction effects between groups and plantar areas. FINDINGS: No interaction effects were found for any of the investigated variables: peak pressure (P = 0.61), contact area (P = 0.38), contact time (P = 0.91), and the pressure-time integral (P = 0.50). INTERPRETATION: These findings indicated that the patterns of plantar pressure distribution were not affected in recreational runners with plantar fasciitis when compared to control runners. Pain also did not interfere with the dynamic patterns of the plantar pressure distributions.

Rearfoot alignment and medial longitudinal arch configurations of runners with symptoms and histories of plantar fasciitis.

OBJECTIVE: To evaluate and compare rearfoot alignment and medial longitudinal arch index during static postures in runners, with and without symptoms and histories of plantar fasciitis (PF). INTRODUCTION: PF is the third most common injury in runners but, so far, its etiology remains unclear. In the literature, rearfoot misalignment and conformations of the longitudinal plantar arch have been described as risk factors for the development of PF. However, in most of the investigated literature, the results are still controversial, mainly regarding athletic individuals and the effects of pain associated with these injuries. METHODS: Forty-five runners with plantar fasciitis (30 symptomatic and 15 with previous histories of injuries) and 60 controls were evaluated. Pain was assessed by a visual analogue scale. The assessment of rearfoot alignment and the calculations of the arch index were performed by digital photographic images. RESULTS: There were observed similarities between the three groups regarding the misalignments of the rearfoot valgus. The medial longitudinal arches were more elevated in the group with symptoms and histories of PF, compared to the control runners. CONCLUSIONS: Runners with symptoms or histories of PF did not differ in rearfoot valgus misalignments, but showed increases in the longitudinal plantar arch during bipedal static stance, regardless of the presence of pain symptoms.

In-shoe plantar pressure distribution during running on natural grass and asphalt in recreational runners.

The type of surface used for running can influence the load that the locomotor apparatus will absorb and the load distribution could be related to the incidence of chronic injuries. As there is no consensus on how the locomotor apparatus adapts to loads originating from running surfaces with different compliance, the objective of this study was to investigate how loads are distributed over the plantar surface while running on natural grass and on a rigid surface--asphalt. Forty-four adult runners with 4+/-3 years of running experience were evaluated while running at 12 km/h for 40 m wearing standardised running shoes and Pedar insoles (Novel). Peak pressure, contact time and contact area were measured in six regions: lateral, central and medial rearfoot, midfoot, lateral and medial forefoot. The surfaces and regions were compared by three ANOVAS (2 x 6). Asphalt and natural grass were statistically different in all variables. Higher peak pressures were observed on asphalt at the central (p<0.001) [grass: 303.8(66.7)kPa; asphalt: 342.3(76.3)kPa] and lateral rearfoot (p<0.001) [grass: 312.7(75.8)kPa; asphalt: 350.9(98.3)kPa] and lateral forefoot (p<0.001) [grass: 221.5(42.9)kPa; asphalt: 245.3(55.5)kPa]. For natural grass, contact time and contact area were significantly greater at the central rearfoot (p<0.001). These results suggest that natural grass may be a surface that provokes lighter loads on the rearfoot and forefoot in recreational runners.

Rearfoot alignment and medial longitudinal arch configurations of runners with symptoms and histories of plantar fasciitis

OBJECTIVE: To evaluate and compare rearfoot alignment and medial longitudinal arch index during static postures in runners, with and without symptoms and histories of plantar fasciitis (PF). INTRODUCTION: PF is the third most common injury in runners but, so far, its etiology remains unclear. In the literature, rearfoot misalignment and conformations of the longitudinal plantar arch have been described as risk factors for the development of PF. However, in most of the investigated literature, the results are still controversial, mainly regarding athletic individuals and the effects of pain associated with these injuries. METHODS: Forty-five runners with plantar fasciitis (30 symptomatic and 15 with previous histories of injuries) and 60 controls were evaluated. Pain was assessed by a visual analogue scale. The assessment of rearfoot alignment and the calculations of the arch index were performed by digital photographic images. RESULTS: There were observed similarities between the three groups regarding the misalignments of the rearfoot valgus. The medial longitudinal arches were more elevated in the group with symptoms and histories of PF, compared to the control runners. CONCLUSIONS: Runners with symptoms or histories of PF did not differ in rearfoot valgus misalignments, but showed increases in the longitudinal plantar arch during bipedal static stance, regardless of the presence of pain symptoms.

Efeito de diferentes protocolos de treinamento de força sobre parâmetros morfofuncionais, hormonais e imunológicos / Effects of different resistance training protocols over the morphofunctional, hormonal and immunological parameters

O objetivo do estudo foi examinar a influência de dois diferentes protocolos de treinamento de força sobre parâmetros antropométricos (peso, IMC, massa gorda), funcionais (teste de 1-RM e teste de repetições máximas) e relacionados ao sistema endócrino (concentração de testosterona e de cortisol) e ao sistema imunológico (concentração de glutamina e de IgG). Participaram do estudo 12 homens treinados (27,4 ± 4,8 anos). Esses indivíduos foram aleatoriamente divididos em dois grupos, que posteriormente foram submetidos a dois protocolos de treinamento distintos: Múltiplas séries (MS) e Tri-set (TS). Amostras de sangue foram coletadas antes e depois de uma sessão de exercício de força, no início e no final do período de oito semanas de treinamento. Não foram observadas alterações nos parâmetros morfo-funcionais (com exceção do teste de repetições máximas para o agachamento). Com relação aos parâmetros endócrinos, foi observado que o TS provocou aumento significativo do cortisol, imediatamente após a sessão de treino, tanto no início como no final das oito semanas (p < 0,05). Ao observar o comportamento da relação testosterona para cortisol (T:C), pode-se notar um marcante aumento no grupo submetido ao protocolo MS após oito semanas de treinamento (p < 0,05). Com relação aos parâmetros imunológicos, não foi observada alteração na concentração de imunoglobulina G. A concentração de glutamina sofreu decréscimo após oito semanas em ambos os grupos. Esse decréscimo foi mais acentuado no grupo TS (p < 0,05). Os resultados obtidos sugerem que o método TS impôs maior estresse ao organismo. Além disso, os dados também indicam que o protocolo MS promove um ambiente mais propício ao anabolismo, após oito semanas de treinamento. Entretanto, ambos os métodos falharam em promover alterações significativas nos parâmetros morfofuncionais.

The purpose of this study was to assess the influence of two different resistance training protocols on the anthropometric (weight, BMI, fat mass), functional parameters (1-MR test, and maximal repetition test) and the parameters related to the endocrine system (testosterone and cortisol concentrations), as well as to the immunological system (glutamine and IgC concentrations). The study was composed by twelve trained men (27.4 ± 4.8 years), who were randomly divided in two groups that later were submitted to two different training protocols: the Multiple Series (MS), and Tri-set (TS). Blood samplings were collected before and after an resistance training session in the beginning and the end of the 8 weeks training period. It was observed no alterations in the morphofunctional parameters (except as to the maximal repetition test for the squat). As to the endocrine parameters, it was observed that the TS caused a significant increase in the cortisol immediately after the training session both in the beginning and in the end of the eight weeks (p < 0.05) period. Upon the observation of the testosterone vs. cortisol ratio (T:C) behavior, it can be observed a noticeable increase in the group submitted to the MS protocol after the 8 weeks training period (p < 0.05). As to the immunological parameters, it was observed no alterations in the concentration of the immunoglobulin G. The concentration of the glutamine suffered a decrease after 8 weeks in both groups. That decrease had a higher accentuation in the TS group (p < 0.05). Results attained suggest that the TS method imposed a higher stress to the body. Furthermore, these data also indicate that the MS protocol promotes a more propitious environment to the anabolism after the 8 weeks training period. However, both methods did not succeed in promoting significant changes in the morphofunctional parameters.

El objetivo del estudio fué examinar la influencia de 2 protocolos diferentes de entrenamiento de fuerza sobre parámetros antropométricos (peso, IMC, masa grasa), funcionales (prueba de 1-RM y prueba de repeticiones máximas) y los parámetros relacionados al sistema endocrino (concentraciones de testosterona y de cortisol) y al sistema inmunológico (la concentración del glutamina y de IgG). Participaron en el estudio 12 hombres entrenados (27,4 ± 4,8 años). Estos individuos fueron aleatoriamente divididos en 2 grupos que después se sometieron a 2 protocolos de entrenamiento en dos series diferentes, Múltiple (MS) y Tri-juego (TS). Las muestras de sangre eran reunidos antes y después de una sesión de ejercicio de fuerza, al principio y en el fin del período de 8 semanas de entrenar. No se observaron alteraciones en los parámetros morfo-funcionales (salvo la prueba de repeticiones máximas para el agachamiento). Con respecto a los parámetros endócrinos, se observó que TS provocó un aumento significante del cortisol, inmediatamente después de la sesión de entrenamiento, al principio y en el fin de las 8 semanas (p < 0,05). Al observar la conducta de la testosterona en relación con el cortisol (T:C), puede notarse un aumento excelente en el grupo sometido al MS protocolar después de 8 semanas de entrenar (p < 0,05). Con respecto a los parámetros inmunológicos, no se observó alteración en la concentración de la imunoglobulina G; la concentración del glutamina sufrió una disminución después de 8 semanas en ambos grupos. Esta disminución se acentuó más en el TS de grupo (p < 0,05). Los resultados obtenidos sugieren que el método TS impuso una tensión más grande al organismo. Además, los datos también indican que el MS protocolar promueve una atmósfera más favorable al anabolismo, después de 8 semanas de entrenar. Sin embargo, ambos métodos fallaron promoviendo las alteraciones significantes en los parámetros morfo-funcionales.

Força reação do solo durante a marcha com uso do tênis e sandália plataforma / Ground reaction force during gait with shoes and high-heel sandal

O objetivo deste estudo foi analisar a força reação do solo durante a marcha em cadência auto-selecionada, comparando as características entre a marcha descalça e com o uso de sandálias de salto plataforma e tênis esportivo. A amostra constituiu-se de 8 mulheres com média de idade de 22,9 (4,1) anos. A força reação do dolo foi adquirida com uma plataforma de força da AMTI e analisada no Origin v 6..0. Os resultados demonstraram um aumento do primeiro e do segundo picos verticais de força com o uso de sandália em relação à marcha descalça de 1,09 (0,06) PC para 1,18 (0,07) PC, diminuição do pico passivo de 0,61 (0,12) PC para 0,40 (0,16) PC e sua taxa de crescimento de 33,64 (16,91) PC/s para 16,19 (4,93) PC/s. A taxa de crescimento do primeiro pico de força diminuiu, mas não apresentou diferenças significativas de 7,98 (1,78) PC/s para 7,86 (3,82) PC/s. Essa diminuição das taxas de crescimento e aumento dos picos de força com o uso de sandália sugerem aumento de sobrecarga nas articulações dos membros inferiores, resultado principalmente da rigidez do solado e da instabilidade provocada pela elevação do centro de gravidade, justificando a diminuição de velocidade verificada. A menor magnitude do primeiro pico da FRS vertical de 1,14 (0,05) PC, com a utilização do tênis demonstra que na comparação com a sandália cujo primeiro pico foi de 1,18 (0,07) PC/s, a rigidez do solado é fator determinante para a magnitude desta variável. Esses resultados deveriam ser considerados para o desenvolvimento e a produção de sandálias com salto que promovessem maior conforto aos usuários

The purpose of this study was to analyze the ground reaction force during gait in auto-selected cadence, comparing the characteristic of barefoot gait between wearing of high-heel sandal and the wearing of sport shoes. The sample was constituted with 8 women with average age of 22,9(4,1) years old. The ground reaction force was acquired with a force platform by AMTI and analyzed with the Origin v 6.0. The results showed an increase of the first and second force vertical peaks with the wearing of sandal comparing to barefoot gait of 1,09 (0,06)BW to 1,18(0,07)BW, reduction of passive peak from 0,61(0,12)BW to 0,40(0,16)BW and it’s growth rate from 33,64(16,91)BW/ s to 16,19(4,93)BW/s. The growth rate of the first force peak decreased, but didn’t show significant differences from 7,98 (1,78)BW/s to 7,86 (3,82)BW/s. This reduction of the growth rate and increase of the force peaks on the wearing sandals situation suggests an increase on overload of the lower extremities, mainly caused by rigid-soled and instability generated by gravity center raise, justifying the decrease of speed encountered. The first peak’s minor magnitude of the vertical GRF of 1,14(0,05)BW verified on the sport shoes situation when comparing to the first peak’s when wearing the sandals 1,18(0,07)BW suggests that the rigid-soled is determinant factor for this variable magnitude. These results should be considered for development and production of high-heel sandals that would promote more comfort for the users.