Effects of Resistance Training of Upper Limb and Trunk Muscles on Soccer Instep Kick Kinematics.

The upper body and trunk muscles are crucial to perform soccer kicks. Resistance training targeting these muscles may modify the pattern adopted during kicking. This study aimed to investigate the effect of resistance training of the arm and anterior trunk muscles on instep kicking kinematics. Twenty-six male participants were randomly allocated into a training group or control group. The training group underwent resistance training of arm and trunk muscles and practiced the instep kick for 8 weeks. The control group only practiced kicking during the same period. The trunk, hip, and knee kinematics were assessed during the instep kick before and after the intervention. Kinematics were analyzed according to their data distribution with statistical parametric or nonparametric mapping. The effect of the training on the 1-repetition maximum test was analyzed using a repeated-measures multivariate analysis of variance. The training group showed greater hip extension after the training during the backswing phase (Hedge g effect size of 0.316-0.321) and increased 1-repetition maximum for all exercises. There were no other differences. The present study documented the nonlocal effect of strengthening training in which arm and trunk muscle training resulted in changes in hip kinematics during the backswing phase of the instep kick.

Vertical stiffness and lower limb inter-joint coordination in older versus younger runners.

Older runners (OR) are increasing their participation in races. Aging may impact the adopted running pattern. Hence, the analysis of stiffness and the inter-joint lower limb coordination in the sagittal plane could contribute to investigating this impact. This study aimed to compare the vertical stiffness (Kvert) and the inter-joint lower limb coordination in the sagittal plane between younger runners (YR) and OR. This cross-sectional study recruited 15 YR males and 15 OR males. The pelvis and lower limb motions were assessed while running on a treadmill at self-selected (range OR: 1.94-3.75 m.s-1, YR: 2.08-4.17 m.s-1) and fixed speeds (3.33 m.s-1). Hip-ankle, knee-ankle, and hip-knee coupling angle (CA) and its variability (CAV) were extracted using the vector coding method. Mann-Whitney U tests compared Kvert between groups at each running speed. Watson's U2 tests compared the mean CA between groups in three intervals of the contact phase at each running speed. Statistical Parametric Mapping independent t-test compared the CAV curve between groups at each running speed. OR showed greater Kvert than YR at both speeds. Hip-ankle CA pattern differed between groups during the early stance at both speed conditions. OR showed in-phase, distal dominancy in hip-ankle CA, whereas YR showed anti-phase, proximal dominancy. Knee-ankle CA was distinct only at self-selected speed, in which OR showed in-phase, proximal dominancy, while YR exhibited anti-phase, proximal dominancy. CAV did not differ between groups. The findings showed that OR adopted a stiffer pattern characterized by distinct inter-joint lower limb CA, at early stance, during self-selected and fixed speeds.

Runners with a history of shank and foot injury: Interactions among local musculoskeletal factors, age, and running experience.

OBJECTIVE: To identify subgroups of runners' profiles who had or did not have a History of Running-Related Injury in the Shank and Foot (HRRI-SF). DESIGN: Cross-sectional. METHODS: Clinical measures of passive ankle stiffness (measured as ankle position (compliance) to index passive joint stiffness), forefoot-shank alignment, peak torque of ankle plantar flexors, years of running experience, and age were analyzed through Classification and Regression Tree (CART). RESULTS: The CART identified four subgroups of runners with a greater prevalence of HRRI-SF: (1) ankle stiffness ≤0.42°; (2) ankle stiffness >0.42°, age ≤23.5 years, and forefoot varus >19,64°; (3) ankle stiffness >0.42°, age >62.5 years, and forefoot varus ≤19.70°; (4) ankle stiffness >42°, age >62.5 years, forefoot varus >19.70°, and running experience ≤7 years. Three subgroups had a lower prevalence of HRRI-SF: (1) ankle stiffness >0.42° and age between 23.5 and 62.5 years; (2) ankle stiffness >0.42°, age ≤23.5 years, and forefoot varus ≤14.64°; (3) ankle stiffness >0.42°, age >62.5 years, forefoot varus >19.7°, and running experience >7 years. CONCLUSION: One runner profile subgroup showed that higher ankle stiffness could predict HRRI-SF without association with other variables. Distinct interactions among variables characterized the other subgroups' profiles. The identified interactions among the predictors used to characterize the runners' profiles could be used in clinical decision-making.

Biofeedback interventions for short term upper limb function following stroke: A systematic review with meta-analysis.

BACKGROUND: Biofeedback has been used by rehabilitation professionals in the treatment of poststroke function impairments. PURPOSE: Investigate the efficacy of any type of biofeedback intervention for the treatment of upper limb function in individuals following stroke. STUDY DESIGN: Systematic review of literature with meta-analysis. METHODS: Literature searches were conducted using MESH terms and text words in PubMed, Lilacs, Scielo, Scopus, PEDro, and Web of Science databases. The main outcome was improvement in upper limb's motor function and motor function in activities of daily living. We calculated the Mean Difference and Standardized Mean Difference for the assessment scales reported as primary outcome. The methodological quality of included studies was assessed using PEDro scale. The overall quality of the evidence was assessed using GRADE system. RESULTS: From 1360 articles identified, 16 were included in the review (09 in the meta-analysis). Three forest plots of hemiparesis and one of hemiplegia showed that biofeedback therapy associated with conventional therapy has a greater improvement in participants upper limb motor function when compared to isolated conventional therapy. Two forest plots of hemiparesis and one of hemiplegia showed no superiority in participants improvement for biofeedback associated with conventional therapy when compared to isolated conventional therapy. CONCLUSION: Biofeedback therapy associated with conventional therapy showed a small clinical effect when associated to conventional therapy and very low quality of evidence. Although further research with higher quality evidence is needed.

Lower limb inter-joint coordination patterns are associated with walking experience in toddlers according to limb and stance periods.

Walking experience is crucial for inter-joint coordination during gait acquisition. Toddlers show asymmetrical lower limb function during early locomotion for transferring body weight (regulatory limb) and steering the direction of walking (impulse limb). This study aimed to investigate the association between coordination patterns and walking experience, and between coordination variability and walking experience according to healthy toddlers' lower limb function and stance periods. Typically developing toddlers (n = 22; 17.27 ± 3.13 months) were distributed into two groups: up to (LWE) and greater than (GWE) three months of walking experience. The lower limbs were classified as regulatory or impulse limb and analyzed during the onset (SO), mid (MS), and late (LS) stance intervals. Hip-ankle, knee-ankle, and hip-knee coupling angle (CA) and its variability (CAV) were assessed. A relationship was found between inter-joint coordination pattern and groups, which was distinct according to stance period and lower limb function: (a) hip-ankle CA: at SO for both limbs, MS for the regulatory limb, and LS for the impulse limb; (b) knee-ankle CA: at SO for both limbs and MS for the regulatory limb; (c) hip-knee CA: at SO for both limbs, at MS for the regulatory limb, and LS for the impulse limb. These findings were linked to differences observed in distal joints between groups, mainly at the ankle during stance onset. The CAV was negatively associated with walking experience only in the regulatory limb in the following variables: hip-ankle at MS, knee-ankle at SO, and hip-knee at LS. Findings showed different functional roles of the lower limbs in dealing with the demands of balance and propulsion during early walking.

The Influence of the Shoe over the Medial Foot Arch and the Lower Limbs Kinematics in Toddlers.

Objective To evaluate the biomechanical behavior of the medial longitudinal arch (MLA) of the foot and the kinematic parameters of the lower limbs with biomimetic footwear (BF) and non-biomimetic (NB1, NB2, NB3 and NB4) footwear in children at the beginning of the gait acquisition phase. Methods Four toddlers were evaluated at the beginning of the gait acquisition phase under the following conditions: walking barefoot, ambulation with BF and NB1, NB2, NB3 and NB4 footwear in hard floor. BF is described as biomimetic because of its property of emulating natural and irregular floors through a dynamic internal insole. The MLA and kinematics of the hip, knee, and ankle during gait were evaluated by three-dimensional motion analysis system. The similarity between the kinematic curves of barefoot and footwear conditions was analyzed by root mean square error (RMSE). Results The use of BF presented the highest magnitude of MLA and the greatest difference in relation to barefoot condition (higher RMSE). The BF showed less difference in the kinematics of the knee and ankle joints during gait when compared to barefoot condition (lower RMSE). NB2 footwear presented hip kinematics more similar to barefoot condition (lower RMSE). Conclusion Biomimetics footwear and NB2 shoes (both with wider forefoot region) generated smaller differences in lower limbs compared to barefoot. In addition, the MLA was higher in the BF, probably because different design from other shoes.

The Influence of the Shoe over the Medial Foot Arch and the Lower Limbs Kinematics in Toddlers / A influência de calçados no arco longitudinal medial do pé e na cinemática dos membros inferiores de crianças no início da fase de aquisição de marcha

Abstract Objective To evaluate the biomechanical behavior of the medial longitudinal arch (MLA) of the foot and the kinematic parameters of the lower limbs with biomimetic footwear (BF) and non-biomimetic (NB1, NB2, NB3 and NB4) footwear in children at the beginning of the gait acquisition phase. Methods Four toddlers were evaluated at the beginning of the gait acquisition phase under the following conditions: walking barefoot, ambulation with BF and NB1, NB2, NB3 and NB4 footwear in hard floor. BF is described as biomimetic because of its property of emulating natural and irregular floors through a dynamic internal insole. The MLA and kinematics of the hip, knee, and ankle during gait were evaluated by three-dimensional motion analysis system. The similarity between the kinematic curves of barefoot and footwear conditions was analyzed by root mean square error (RMSE). Results The use of BF presented the highest magnitude of MLA and the greatest difference in relation to barefoot condition (higher RMSE). The BF showed less difference in the kinematics of the knee and ankle joints during gait when compared to barefoot condition (lower RMSE). NB2 footwear presented hip kinematics more similar to barefoot condition (lower RMSE). Conclusion Biomimetics footwear and NB2 shoes (both with wider forefoot region) generated smaller differences in lower limbs compared to barefoot. In addition, the MLA was higher in the BF, probably because different design from other shoes.

Resumo Objetivo Avaliar o comportamento do arco longitudinal medial do pé (ALM) e os parâmetros cinemáticos dos membros inferiores durante a deambulação com calçados biomiméticos (CBs) e não biomiméticos (NB1, NB2, NB3 e NB4) em crianças no início da fase de aquisição da marcha. Métodos Foram avaliadas quatro crianças no início da fase de aquisição da marcha nas seguintes condições: andar descalço, andar com CBs e calçados NB1, NB2, NB3 e NB4 em solo plano. O calçado biomimético é descrito como biomimético por emular pisos naturais e irregulares por meio de uma palmilha interna dinâmica. O ALM e a cinemática do quadril, joelho e tornozelo durante a marcha foram avaliados por meio de sistema de análise do movimento tridimensional. A similaridade entre as curvas cinemáticas das condições descalça e com calçado foi analisada por meio do cálculo de root mean square error (RMSE). Resultados O CB foi o que apresentou maior magnitude do ALM e maior diferença do ALM em relação à condição descalça (maior RMSE). O CB apresentou ainda menor diferença na cinemática das articulações do joelho e tornozelo durante a marcha quando comparado à condição descalça (menor RMSE). O calçado NB2 apresentou a cinemática do quadril mais semelhante à condição descalça (menor RMSE). Conclusão Os calçados CB e NB2 que apresentam a região do antepé mais larga geraram menores diferenças na cinemática dos membros inferiores. Além disso, o ALM foi maior no CB provavelmente devido a seu design ser diferente daquele dos demais calçados.

The use of Horizon graphs to visualize bilateral biomechanical time-series of multiple joints.

Movement analysis provides a vast amount of data, which, frequently, are not used in the clinical decision-making process. For example, traditional gait data visualization is based on a time-based display of joint angles, but part of the information is lost when these time-series are averaged across different gait strides. Horizon graph is a data display method that increases the density of time-series data by horizontally dividing and layering multiple filled line graphs. This higher data density increases the amount of information displayed in the same graph and, consequently, enables visual data comparisons between multiple time series. Horizon graph of kinematic data allows displaying several cycles of different joints and their respective continuous symmetry ratio between sides. The aim of this work is to introduce the Horizon graph as a method to analyze kinematic gait data and help to characterize its symmetry. Examples of Horizon graph application to running is offered. Horizon graph may prove to be a useful clinical tool to visualize kinematic time-series and facilitate their clinical interpretation.•Continuous gait time series is a powerful tool for clinical analysis.•Horizon graph, higher data density graph, increases the information displayed.•Horizon graph is a clinical tool to visualize kinematic curves.

Runners with a history of injury have greater lower limb movement regularity than runners without a history of injury.

This study aimed to investigate the regularity of the lower limb joint kinematics in runners with and without a history of running-related injuries. The second aim was to verify if the movement pattern regularities are different among the lower limb joints. Eighteen asymptomatic recreational runners with and without a history of running-related injury participated in this study. Lower limb kinematics in the sagittal plane were recorded during running on a treadmill at a self-selected speed. The regularities of the time series of hip, knee, and ankle were analysed using sample entropy (SampEn). A mixed analysis of variance was used to investigate differences between groups and among joints. Runners with a history of injury had lower SampEn values than runners without a history of injury. Ankle kinematics SampEn was higher than that of the knee and hip. Knee kinematics had higher values of SampEn than that of the hip. Runners with a history of running-related injury had greater joint kinematic's regularity. This result suggests that, even in asymptomatic runners, previous injuries could influence the movement pattern regularity. Also, the regularity was different among joints. The ankle demonstrated the lowest regularity, reinforcing the different functions that lower limb joints perform during running.

Foot pronation affects pelvic motion during the loading response phase of gait.

BACKGROUND: Increased foot pronation during walking has been associated with low back pain. This association may be due to the impact of increased pronation on pelvic motion. OBJECTIVE: To investigate the effects of increased bilateral foot pronation on pelvic kinematic in frontal and transverse planes during the loading response phase of gait. METHODS: Pelvic, hip, and foot angular positions of 20 participants were collected while they walked at fast speed wearing flat and medially inclined insoles inserted in the shoes. Pelvic motion in frontal and transverse planes was analyzed during the loading response phase. Foot eversion-inversion was analyzed during the complete stance phase to verify the insoles effectiveness in inducing increased pronation and to exclude excessive pronators. RESULTS: Inclined insoles were effective in inducing increased foot pronation. Pelvic and hip motion were altered in the increased pronation condition compared to the control condition. In the frontal plane, mean pelvic position was more inclined to the contralateral side (mean difference [MD]: 0.54°; 95%CI: 0.23, 0.86) and its range of motion (ROM) was reduced (MD: 0.50°; 95%CI: 0.20, 0.79). In the transverse plane, mean pelvic position was less rotated toward the contralateral leg (MD: 1.03°; 95%CI: 0.65, 1.60) without changes in ROM (MD: 0.04°; 95%CI: -0.17, 0.25). The hip was more internally rotated (MD: 1.37°; 95%CI: 0.76, 1.98) without changes in ROM (MD: 0.10°; 95%CI: -1.02, 1.23). CONCLUSION: Increased bilateral foot pronation changes pelvic motion during walking and should be assessed, as a contributing factor to possible pelvic and lower back disorders.

The trunk is exploited for energy transfers of maximal instep soccer kick: A power flow study.

The purpose of this study was to investigate the angular kinetic energy transfers and expenditure among the trunk (bisegmented), the pelvis and the kick limb during maximal soccer instep kicking, and to characterize kicking kinetics and kinematics. Eighteen adult male amateur soccer players (24.0 ± 4.1 years old) were assessed. Three-dimensional kinematics and ground reaction force were measured. A 6-degrees-of-freedom model was assumed, comprising the upper trunk, lower trunk, pelvis, thigh, shank and foot, and the thoraco-lumbar, lumbo-pelvic, hip, knee, and ankle joints. Angular kinematics and joint moments were computed. Power flow analysis was done by calculating the joint powers (to describe joint-to-segments energy transfers) and the proximal and distal segment powers (to describe segment-to-segment transfers). Power, kinematic and kinetic time series were presented to describe the energy flows' directions. The total mechanical energy expenditure (TMEE) at each joint was also calculated. The TMEEs pointed to substantial energy expenditure at the trunk (27% of the summed work produced by the analyzed joints). In the initial phases of kicking, the trunk generates downward energy flows from the upper to the lower trunk and from the lower trunk to the pelvis, and then to the lower limb, sequentially, which favors angular motions for ball contact. There is a formation and release of a tension arc only at the hip joint, and deceleration of the segments slightly sooner than ball contact, differently from theoretical accounts. There are energy flows, hitherto unknown, among the trunk, pelvis and kick limb, revealing mechanical strategies of kicking.

Hip passive stiffness is associated with midfoot passive stiffness.

BACKGROUND: Hip motion in the transverse plane is coupled with foot motion in the frontal plane during closed kinematic activities, such as gait. Considering that movement patterns and bone alignment might influence passive mechanical properties of joints in the long term, it is possible that hip passive stiffness and foot complex stiffness and alignment are related to each other. OBJECTIVES: To investigate whether hip passive stiffness, midfoot passive stiffness and shank-forefoot alignment are related to each other. METHOD: Thirty healthy adult individuals with a mean age of 25.4 years participated (18 women and 12 men). The Foot Torsimeter was used to measure midfoot stiffness, and hip stiffness and foot alignment were measured using clinical measures. Pearson and Spearman correlation coefficients were calculated to test the associations between each pair of variables, with α = 0.05. RESULTS: Hip stiffness was positively correlated with midfoot absolute stiffness (r = 0.41, p = 0.02), indicating that increased hip stiffness is associated with increased midfoot stiffness. There were no associations between shank-forefoot alignment and the other variables. CONCLUSIONS: In clinical settings, individuals with reduced hip passive stiffness may also have reduced midfoot passive stiffness, and vice versa. Shank-forefoot alignment is not linearly associated with hip or midfoot passive stiffness.

Midfoot passive stiffness affects foot and ankle kinematics and kinetics during the propulsive phase of walking.

The midfoot joint complex (MFJC) is related to the mechanics and efficiency of the walking propulsive phase and low midfoot passive stiffness may require compensatory foot and ankle joint moments to avoid excessive pronation and inefficient propulsion. This study aimed to investigate the kinematics and kinetics of the MFJC and ankle during the propulsive phase of walking in subjects with larger and smaller midfoot passive stiffness. MFJC passive stiffness of 20 healthy adult participants, and the kinematics and kinetics of the MFJC (forefoot-rearfoot) and ankle (rearfoot-shank) during the stance phase of walking were measured. The participants were divided equally into two groups according to the MFJC passive stiffness. Ranges of motion (ROM) and mean joint moments were computed for the late stance. Independent t-tests (α = 0.05) revealed that subjects with lower midfoot passive stiffness showed an increased MFJC sagittal ROM (flattened longitudinal arch) (p = 0.002), increased ankle frontal ROM (more everted positions) (p = 0.002), increased MFJC frontal ROM (more inverted positions) (p = 0.019), as well as a tendency for larger ankle sagittal ROM (p = 0.056). They also showed increased MFJC (p = 0.021) and ankle (p = 0.018) moments in the sagittal plane, increased MFJC moment in the frontal plane (p = 0.047) and a tendency for a predominant ankle moment in the frontal (p = 0.058). Foot and ankle joint moments are possible strategies to reduce pronation and improve propulsion, but not sufficient to prevent the altered kinematics related to low midfoot stiffness. Therefore, midfoot passive stiffness is critical for foot and ankle kinematics and kinetics during walking propulsive phase and is a potential target of interventions.

Current clinical practice and return-to-sport criteria after anterior cruciate ligament reconstruction: a survey of Brazilian physical therapists.

BACKGROUND: Adherence to the use of recommended measures/criteria for return to sport clearance after anterior cruciate ligament reconstruction is crucial for successful rehabilitation. OBJECTIVES: The purpose of this study was to describe the current clinical practice of Brazilian physical therapists that treat patients after anterior cruciate ligament reconstruction, including the measures/criteria used to support the decision-making process regarding return to sport. The secondary aim was to investigate factors associated with the use of the most recommended measures/criteria for return to sport. METHODS: An electronic survey questionnaire was sent to Brazilian physical therapists. The survey consisted of questions about demographics and professional and clinical practice data related to anterior cruciate ligament reconstruction postoperative rehabilitation and return to sport criteria. Descriptive statistics and chi-square tests were used for analyses. RESULTS: A sample of 439 professionals participated in the survey. Only 6.4% of the physical therapists use the most recommended measures/criteria for return to sport after anterior cruciate ligament reconstruction. Professional certification in Sports Physical Therapy was the only factor associated with the use of these recommended measures/criteria (p=0.02). The measures most used for return to sport clearance were related to physical factors (65.3% to 75.1%), such as range of motion and muscle strength. A small number of professionals use questionnaires to assess functional (16.6%) and psychological (19.1%) aspects of their patients to support the decision-making process. CONCLUSION: In their clinical practice, most Brazilian physical therapists do not use the recommended measures/criteria for return to sport after anterior cruciate ligament reconstruction.

Linking Tensegrity to Sports Team Collective Behaviors: Towards the Group-Tensegrity Hypothesis.

Collective behaviors in sports teams emerge from the coordination between players formed from their perception of shared affordances. Recent studies based on the theoretical framework of ecological dynamics reported new analytical tools to capture collective behavior variables that describe team synergies. Here, we introduce a novel hypothesis based on the principles of tensegrity to describe collective behavior. Tensegrity principles operate in the human body at different size scales, from molecular to organism levels, in structures connected physically (biotensegrity). Thus, we propose that a group of individuals connected by information can exhibit synergies based on the same principles (group-tensegrity), and we provide an empirical example based on the dynamics of a volleyball team sub-phase of defense.

Reliability and sensitivity of an instrument for measuring the midfoot passive mechanical properties.

To assess the test - retest reliability and sensitivity of an instrument developed to measure the passive mechanical properties of the midfoot joint complex (MFJC), nine female and three male healthy young adults were evaluated in two different days by two experienced examiners. After proper participant positioning on the instrument, the left forefoot was passively moved from eversion (20°) to inversion (45°) at 2°/s, while the rearfoot and shank were kept immobile. From the instrument's sensing units (torque meter and potentiometer at 100 Hz), passive torque and angle data were registered. Passive stiffness was calculated as the instantaneous slope of the torque vs. angle curve. Therefore, the variables analyzed were resting angle, passive torques and stiffnesses during inversion and eversion through the intraclass correlation coefficient (ICC3,3), standard error of measurement (SEM) and minimal detectable change (MDC95). For the resting angle, ICC3,3 ranged from 0.85 to 0.91, SEM ranged from 1.54° to 1.95° and MDC95 ranged from 4.26° to 5.41°. For the torques, ICC3,3 ranged from 0.85 to 0.97, SEM ranged from 0.09Nm to 0.42Nm and MDC95 ranged from 0.26Nm to 1.16Nm. Finally, for the stiffnesses, ICC3,3 ranged from 0.79 to 0.98, SEM ranged from 0.01Nm/° to 0.04Nm/° and MDC95 ranged from 0.01Nm/° to 0.10 Nm/°. It can be concluded that most of the measurements presented good to excellent reliability with low measurement error. Hence, clinicians and researchers may benefit from the reliable and stable measures provided by the Foot Torsimeter when assessing patients and planning interventions.

Comparison of the rigidity and forefoot - Rearfoot kinematics from three forefoot tracking marker clusters during walking and weight-bearing foot pronation-supination.

Due to the relative motion among the foot rays, the present study aimed to compare the rigidity as well as the forefoot - rearfoot kinematics obtained from three forefoot tracking marker clusters during walking and foot pronation-supination (PROSUP). Nineteen healthy adults performed six walking trials and ten cycles of foot PROSUP movements recorded by an optoelectronic system. Rearfoot's and forefoot's coordinate system were equal for all setups, only the forefoot's tracking markers locations varied among them, which were: (1st) a typical cluster, focusing on the proximal forefoot, (2nd) a second typical cluster, focusing on the distal forefoot and outer metatarsals, and (3rd) a new cluster proposition, focusing on the distal forefoot and central metatarsals. Cluster rigidity was the normalized intra-markers residual, and forefoot - rearfoot angles were the forefoot motion relative to the rearfoot at the peak of each plane of motion. Repeated-measures ANOVA with pairwise comparisons (α=0.05) revealed that the 3rd cluster had the smallest residual (p < 0.001) in comparison with the other clusters for both walking and PROSUP. Differences between forefoot - rearfoot angles were found in the sagittal plane for walking (p < 0.001), but not for PROSUP (p > 0.686). In the frontal and transverse planes, all clusters showed different forefoot - rearfoot angles (p < 0.001) for both walking and PROSUP. The 1st cluster showed smaller ROM in the three planes during walking, and the 3rd cluster was the only that showed forefoot - rearfoot inversion during maximum pronation. Therefore, the new forefoot tracking marker cluster proposition (3rd cluster) captured different forefoot - rearfoot kinematics and can be recommended when the objective is to maximize the cluster rigidity.

Identification of gait events in children with spastic cerebral palsy: comparison between the force plate and algorithms.

OBJECTIVE: To compare the gait event identification of five algorithms recommended in the literature with those provided by force plate (gold standard) in children with unilateral or bilateral spastic cerebral palsy (SCP). METHODS: This was a cross-sectional study of the gait of three girls and four boys with a mean age of 8.6±4.7 years. Four children had unilateral SCP with an equinus gait pattern, and the remaining three children exhibited bilateral SCP with a slide/drag gait pattern. Kinematic and kinetic gait data were collected during barefoot walking at a comfortable speed. From a total of 202 steps, the detection of 202 foot-strike (FS) and 194 toe-off (TO) events by each algorithm was compared with the detection of these same events by the force plate. The error between the events detected by the algorithms and those detected by the force plate was determined in milliseconds. Repeated measures ANOVA was used to compare the errors among the algorithms. RESULTS: The algorithm reported by Ghoussayni et al. showed the best performance in all situations, except for the identification of FS events on the unaffected side in children with unilateral SCP. For these events, the algorithms reported by Desailly et al. and Zeni et al. showed the best performance. CONCLUSION: Ghoussayni et al.'s algorithm can be used to detect gait events in children with SCP when a force plate is not available.

Pelvic Drop Changes due to Proximal Muscle Strengthening Depend on Foot-Ankle Varus Alignment.

BACKGROUND: Strengthening of hip and trunk muscles can modify pelvis and hip movements. However, the varus alignment of the foot-ankle complex (FAC) may influence the effects of muscle strengthening, due to the relationship of FAC alignment with pelvic and hip kinematics. This study evaluated the effects of hip and trunk muscle strengthening on pelvis and hip kinematics during walking, in subgroups with larger and smaller values of FAC varus alignment. In addition, this study evaluated the effects of hip and trunk muscle strengthening on hip passive and active properties, in the same subgroups. METHODS: Fifty-three women, who were divided into intervention and control groups, participated in this nonrandomized controlled trial. Each group was split into two subgroups with larger and smaller values of FAC varus alignment. Hip and trunk muscle strengthening was performed three times a week for two months, with a load of 70% to 80% of one repetition maximum. Before and after strengthening, we evaluated (1) pelvis and hip excursions in the frontal and transverse planes during walking, (2) isokinetic hip passive external rotator torque, and (3) isokinetic concentric and eccentric peak torques of the hip external rotator muscles. Mixed analyses of variance (ANOVAs) were carried out for each dependent variable related to walking kinematics and isokinetic measurements (α = 0.05). RESULTS: The subgroup with smaller varus alignment, of the intervention group, presented a reduction in pelvic drop after strengthening (P = 0.03). The subgroup with larger varus alignment increased pelvic drop after strengthening, with a marginal significance (P = 0.06). The other kinematic excursions did not change (pelvic anterior rotation P = 0.30, hip internal rotation P = 0.54, and hip adduction P = 0.43). The intervention group showed increases in passive torque (P = 0.002), peak concentric torque (P < 0.001), and peak eccentric torque (P < 0.001), independently of FAC alignment. These results suggest that FAC varus alignment influences the effects of strengthening and should be considered when hip and trunk muscle strengthening is used to reduce pelvic drop during walking.

The clinical measure of forefoot-shank alignment partially reflects mechanical properties of the midfoot joint complex.

BACKGROUND: The clinical measure of forefoot-shank alignment (FSA) predicts the amount of foot pronation during weight-bearing tasks. This may be mediated by a relationship between FSA and the mechanical resistance of the midfoot joint complex (MFJC) to forefoot inversion, which is a component of weight-bearing foot pronation. OBJECTIVE: To investigate if the clinical measure of FSA is associated with MFJC mechanical resistance to inversion. DESIGN: Cross-sectional observational study. METHOD: Forty-six healthy individuals (27 males; 19 females) with mean age of 26.4 years (SD 5.3) participated in this study. FSA was measured with photographs. The resistance torque of the MFJC against inversion was measured with a specially designed device. Mean torque, mean torque normalized by body mass, and joint resting position were calculated as variables related to MFJC mechanical resistance. Correlation analyses were carried out to test the association between each MFJC resistance variable and the FSA (α = 0.05). RESULTS: /findings: There were significant moderate correlations of FSA with mean torque (r = -0.44, p = 0.002), mean normalized torque (r = -0.42, p = 0.004) and resting position (r = 0.39, p = 0.007). The clinical measure of FSA is associated to the mechanical resistance of the MFJC: (a) the greater the FSA, the smaller the resistance torques; (b) the greater the FSA, the more inverted the forefoot resting position. CONCLUSIONS: These results showed that the clinical measure of FSA is moderately related to mechanical properties of the MFJC.