Modeling heart rate of individual and team manual handling with one hand using generalized additive mixed models.

OBJECTIVES: Despite the fact that team manual handling is common in different working environments, the previous studies in this regard, particularly those with a physiological approach are quite limited. The present study is an attempt to model the heart rate (HR) of individual and team manual handling with one hand. METHODS: Twenty-five young men (aged 21.24±1.42 year) volunteered for this study. The experiments included individual and two-person handling of the load with three different weights with and without height difference. The participants' HR was registered at the end of the route by a chest-strap pulse monitor and a polar watch according to the manufacturer's recommendation. A multivariate Generalized Additive Mixed Model (MGAMM) was used for modeling heart rate based on explanatory variables of workload, carry method, HRrest, body weight, height, knee height, shoulder height, elbow height, and hand height. The significance level of the tests was considered as <0.05. RESULTS: Based on the MGAMM, the average HR (bpm) of participants increased as the workload increased (P<0.001). Handling the load with a taller person increased the HR compared to shorter partner (P<0.001). Moreover, the nonlinear associations of the resting HR (P<0.001), body weight (P<0.001), height (P<0.001), and the height of elbow, hand and knee (P<0.001) were statistically significant. The adjusted R2 of the model was 0.89 indicating that about 90 percent of the variations observed in HR could be explained by the variables in the model. This was greater than the model considering only linear effects (R2 =0.60). CONCLUSION: The model obtained in this study can predict the heart rate of individual and team one-handed handling with high validity. The MGAMM can be used in modeling heart rate in manual handling.

Team manual handling: a systematic review for identifying research gaps.

Objectives. Team manual handling, a process still common in many jobs, can affect the safety and health of employees. A systematic review of the literature was conducted to identify the research gaps in this area for future studies. Methods. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was followed. Related papers were searched on PubMed, Web of Science, ProQuest and Scopus electronic databases until September 2020. Results. A total of 300 papers were identified, of which 28 were selected for final review based on the respective criteria. The findings of these studies were classified and evaluated based on biomechanical, physiological and psychophysical approaches. No study was found for the epidemiological approach. Only three papers mentioned the body physiological responses in team manual handling. The focus of the related studies found in this field was team lifting. No study was found on team pulling and pushing. Most studies were performed in a laboratory setting using young students who had no experience of team manual handling. Conclusion. The results of this study emphasize the need for further research, especially using the epidemiological and physiological approaches in different tasks of team manual handling in real work environments using experienced workers.

Immediate effects of using insoles with various wedges on activation and co-contraction indices of selected trunk muscles during load lifting.

Trunk muscles play an important role during load lifting and contract to control trunk stability. The aim of present study was to investigate immediate effects of using various insole wedges on activation and co-contraction indices of selected trunk muscles during load lifting. Thirty able-bodied males completed load lifting task using nine various insole wedges. The results showed these significant differences: for normalized mean amplitude of RA muscle between posterior and anterior-medial wedges and for QL muscle between posterior and lateral wedges, for normalized peak amplitude of RA muscle between posterior and anterior-medial wedges, for median frequency of LES muscle between anterior-medial and anterior-lateral wedges, and for co-contraction of RA/TES, RA/LES and RA/MU between posterior and anterior-medial wedges (P = 0.001). These findings should be considered during designation of shoe or insole for work environments. Future studies need to assess other biomechanical aspects of using various insole wedges during work-related tasks.

Design and evaluation of an ergonomic chair for near-ground welding based on muscle activity and usability.

BACKGROUND: Work-related musculoskeletal disorders (WMSDs) are one of the major problems in industrial societies. Awkward postures in theworkplace are considered as a main reasons for these disorders. Therefore, the study and investigation of postures to improve them (in the workplace) have a significant role in appropriate intervention. OBJECTIVE: This study aimed to design an ergonomic chair for near-ground welding operations and evaluate its impact on the electromyography (EMG) activity of a select group of lower limb muscles. METHODS: The EMG activity of lower limb muscles was measured in eight postures consisting of three postures identified via observing welders at work, and five on-chair postures suggested for chair use during welding. The usability of the designed chair was evaluated through the use of the System Usability Scale (SUS). RESULTS: The results showed that the suggested on-chair postures had significantly lower mean muscle activity compared with the identified postures (p < 0.001). Among the identified postures, kneeling posture had the lowest mean muscle activity (p < 0.01), still significantly higher than the mean activity of the on-chair postures (p < 0.001). Applying a 15° slope to the seat pad led to a decrease in muscle activity and an increase in usability score. The usability score of the chair was acceptable in all postures except KCC-90 posture. CONCLUSIONS: Using a suitable chair or support for different work postures can prevent detrimental muscle activities during work and the development of musculoskeletal disorders caused by intense muscle activity due to awkward postures.

The effects of fatigue on synergy of selected lower limb muscles during running.

The purpose of this study was to investigate the effect of fatigue on selected lower extremity muscles synergy during running using non-negative matrix factorization algorithm method. Sixteen male recreational runners participated in this study. The surface electromyographic activity of rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), semitendinosus, gastrocnemius medialis (GM), soleus (SO) and tibialis anterior (TA) were recorded on treadmill at 3.3 m s-1 before and after the fatigue protocol. Synergy pattern and relative muscle weight were calculated by non-negative matrix factorization (NNMF) algorithm method. The results showed that using the VAF method, five muscle synergies were extracted from the emg data during running. After the fatigue, the number of muscular synergies did not show a change, but relative weight of the muscles changed. Fatigue did not have any effect on the structure of muscular synergy, but changed the relative weight of muscles. These changes could be the strategy of the central nervous system to maintain optimal function of the motor system.

Validity and reliability of the Persian version of the Dutch musculoskeletal questionnaire.

Background: Dutch Musculoskeletal Questionnaire (DMQ) is used to examine physical and environmental risk factors and to identify high-risk groups for exposure to the risk factors of musculoskeletal disorders at workplace. The aim of this study was to develop the Persian version of the DMQ and to assess its psychometric properties. Methods: This study was conducted on 212 employees of Gas Transmission Company. Using a standard forward-backward translation procedure, the English version of the questionnaire was translated into Persian and culturally adapted. Content validity was established by 10 expert opinions. The intraclass correlation coefficient (ICC) was used for the statistical analysis of reproducibility. Kuder-Richardson-20 was used for internal consistency and confirmatory factor analysis for structural validity. Results: This study revealed high internal consistency and good test-retest reliability for the Persian version of the questionnaire. The means of the content validity ratio (CVR) and content validity index (CVI) for the total 35 items of the questionnaire were 0.96 and 0.91, respectively. The internal consistency of the factors was satisfactory, ranging from 0.83 to 0.88. Confirmatory factor analysis confirmed the existence of 7 factors in the questionnaire and an acceptable fit for the Persian version of the DMQ. Conclusion: The Persian version of the DMQ has acceptable psychometric properties. Thus, it can be used as a valid instrument to assess workload and to identify high-risk groups of musculoskeletal disorders at workplace.

Effect of Lower Limb Muscle Fatigue on Ground Reaction Force Components During Landing in People With Nonspecific Chronic Low Back Pain.

CONTEXT: The link between landing parameters and lower limb muscle fatigue in association with chronic low back pain (CLBP) is not well understood. OBJECTIVE: To examine the effects of fatigue on the ground reaction force components during landing in people with nonspecific CLBP. DESIGN: Quasi-experimental study. SETTING: Clinical biomechanics laboratory. PARTICIPANTS: A total of 44 subjects were equally divided into a healthy group and a group with CLBP. MAIN OUTCOME MEASURES: The ground reaction force along anterior-posterior (y) and medial-lateral (x) and vertical (z) axes, time to peak (TTP), the rate of force development, and impulses for all axes were calculated. A repeated-measures analysis of variance (group × fatigue) was used to compare the data among groups. RESULTS: In the unfatigued conditions, the amplitudes of Fy3, Fz2, and TTP of Fy1, Fy2, Fz1, Fz2, Fz3, Fz4, rate of force development in Y in the CLBP subjects are significantly different than those in the healthy subjects (P < .05). In the fatigued conditions, the amplitudes of Fz2, Fz3, Fz4, and TTP of Fy2, Fy3, Fy4, Fz2, impulses of X2, Z in the CLBP group were significantly different than those in the healthy subjects (P < .05). Within-group comparisons of measured Fx1, Fy1, Fy2, Fz2, Fz4 and TTP of Fx1, Fy1, Fy2, Fz2, Fz3, Fz4, impulses of X2, z were significantly different from prefatigue to postfatigue in the healthy group (P < .05). Within-group comparisons of measured Fx1, Fy1, Fz1, Fz2 and TTP of Fx5, Fz1, impulses of X2 were significantly differed from prefatigue to postfatigue in the CLBP group (P < .05). CONCLUSIONS: It seems that TTP of ground reaction force variables in CLBP may have clinical values for rehabilitation. Muscle fatigue altered landing performance. However, patients with CLBP will respond differently to lower-extremity fatigue. These altered variables in patients with low back pain are the cause of future injuries or lower-extremity injuries that need to be addressed in further studies.

Patellar bracing affects sEMG activity of leg and thigh muscles during stance phase in patellofemoral pain syndrome.

BACKGROUND: Decreases in patellofemoral pain symptoms with bracing treatment have been established; but, the mechanisms remain unclear. The purpose of this study was to determine the immediate and long-term effects of the patellar bracing on electromyography (EMG) activity of the Vastus Medialis (VM) and Lateralis (VL), Rectus Femoris, lateral Gastrocnemius, Biceps Femoris and Semitendinosus (ST) muscles during level walking. METHODS: 12 eligible women aged 20-30 years with diagnosis of patellofemoral pain participated in the before and after study. Intervention consisted of 8 weeks of patellar bracing. First, patients were tested without brace, then with a brace, and finally eight weeks later without a brace. Surface EMG activation of the selected muscles during level walking was recorded. RESULTS: After eight weeks of patellar bracing, EMG activity of VM muscle was significantly higher when compared to first session without brace (p=0.011) at mid-stance sub-phase. Additionally, EMG activity of ST muscle during first session with brace was significantly lower when compared to first session without brace at mid-stance sub-phase (without brace) (p=0.012). EMG activity of VM muscle after eight weeks of patellar bracing was significantly higher than the first session without brace at late stance and preswing sub-phase (p=0.013). CONCLUSION: Long-term wearing of patellar bracing increases EMG activity of VM during mid-stance and late stance and preswing sub-phases of gait and immediate effect of patellar brace is decrease of EMG activity of ST muscle during mid-stance.

Effects of running-induced fatigue on plantar pressure distribution in novice runners with different foot types.

This study aimed to assess the effects of running-induced fatigue on plantar pressure parameters in novice runners with low and high medial longitudinal arch. Plantar pressure data from 42 novice runners (21 with high, and 21 with low arch) were collected before and after running-induced fatigue protocol during running at 3.3m/s along the Footscan(®) platform. Peak plantar pressure, peak force and force-time integral (impulse) were measured in ten anatomical zones. Relative time for foot roll-over phases and medio-lateral force ratio were calculated before and after the fatigue protocol. After the fatigue protocol, increases in the peak pressure under the first-third metatarsal zones and reduction under the fourth-fifth metatarsal regions were observed in the low arch individuals. In the high arch group, increases in peak pressure under the fourth-fifth metatarsal zones after the running-induced fatigue was observed. It could be concluded that running-induced fatigue had different effects on plantar pressure distribution pattern among novice runners with low and high medial longitudinal foot arch. These findings could provide some information related to several running injuries among individuals with different foot types.

Comparación de la actividad muscular seleccionada del tronco y las extremidades inferiores en la forma de caminar de las mujeres jóvenes con pies supinadores, pronadores y neutros / Comparison of selected muscular activity of trunk and lower extremities in young women’s walking on supinated, pronated and normal foot

Los cambios en la estructura anatómica del pie reducen su capacidad de rendimiento normal. Este estudio trató de comparar los músculos seleccionados del tronco y las extremidades inferiores al caminar, en personas con diferentes tipos de pie. Se clasificó a 45 estudiantes femeninas en tres grupos, dependiendo de la estructura de sus pies, es decir, pronadora, supinadora y neutra. El médico especialista definió los tipos de pie mediante el índice postural del pie y rayos X. Se registraron las actividades electromiográficas de los músculos tibial anterior, peroneo lateral largo, gemelo interno, bíceps femoral, glúteo medio, externo oblicuo y erector de la columna en los tres grupos, al realizar un recorrido determinado, con una velocidad de marcha auto-seleccionada. Se grabó con una cámara cada esfuerzo simultáneo al registro electromiográfico. Se utilizó el test ANOVA con un factor para comparar los grupos, con un nivel de significación de 0,05. La actividad de los músculos tibial anterior y gemelo interno fue superior en el grupo de pie pronador que en los grupos de pie supinador y neutro, durante la fase de contacto del talón de la marcha (p = 0,001). El grupo de pie supinador reflejó una activación superior del músculo peroneo lateral largo que el resto de los grupos (p = 0,001). No se observaron diferencias significativas en los cuatro músculos restantes (p > 0,05). Durante la fase de media distancia, para el peroneo lateral largo, el grupo de pie supinador reflejó una mayor actividad en comparación a los demás grupos, mientras que el grupo de pie pronador reflejó una mayor actividad muscular para el glúteo medio que los demás grupos (p = 0,001). Se produjo una diferencia significativa entre los grupos de pie pronador y pie neutro para el externo oblicuo (p = 0,001). Con arreglo a los hallazgos de este estudio, los cambios en el desempeño muscular en los grupos de pies pronadores y supinadores son más notorios que en el grupo de pie neutro

Changes in anatomical structure of the foot reduce the foot ability for normal performance. This study aimed to compare selected muscles of trunk and lower extremities during walking in individuals with different foot types. Forty-five female students were categorized into three groups depending on their foot structures namely, pronated, supinated and normal feet. Foot types defined by foot posture index and X-ray under the specialist physician. Electromyography activities were recorded from muscles of tibialis anterior, peroneus longus, medial gastrocnemius, biceps femoris, gluteus medius, external oblique and erector spinae in three groups while walking in determined path with self-selected gait speed. Each effort simultaneous with electromyography registration was recorded with camera. One-way ANOVA test was used to compare the groups at significance level of 0.05. The activity of muscle of tibialis anterior and medial gastrocnemius was greater in pronated foot group than that in supinated and normal groups during heel contact phase of gait (p = 0.001). Supinated foot group exhibited a greater peroneus longus activation than the other groups (p = 0.001). No significant differences were observed for remaining four muscles (p > 0.05). During midstance phase, peroneus longus, supinated foot group exhibited a greater activity compared to other groups while pronated foot group exhibited a greater muscle activity for gluteus medius than others (p = 0.001). There was a significant difference between normal and pronated foot groups for external oblique (p = 0.001). Regarding the findings of this study, the muscular performance changes in pronated and supinated foot groups are more noticeable than that in normal foot type

The comparison of scapular upward rotation and scapulohumeral rhythm between dominant and non-dominant shoulder in male overhead athletes and non-athletes.

Previous studies have stated that the scapulohumeral rhythm dysfunction can make person prone to glenohumeral joint pathologies. The purpose of this study was to compare scapular upward rotation and scapulohumeral rhythm between dominant and non-dominant shoulder in male overhead athletes and non-athletes. Seventeen overhead athletes and seventeen non-athletes volunteered for this study. Two inclinometers were used to measure humeral abduction and scapular upward rotation in rest position, 45°, 90° and 135° humeral abduction in frontal plane. Findings indicated there was no significant asymmetry in scapular upward rotation and scapulohumeral rhythm in different abduction angles between dominant and non-dominant shoulder in non-athletes. In contrast, overhead athletes' dominant shoulders have more downward rotation in scapular rest position and more upward rotation in 90° and 135° shoulder abduction than non-dominant shoulders. Also, overhead athletes presented scapulohumeral rhythm asymmetry between dominant and non-dominant shoulder in 90° and 135° humeral abduction as dominant shoulders have less scapulohumeral rhythm ratio than non-dominant shoulders. Furthermore, overhead athletes dominant shoulders have more scapular downward rotation in scapular rest position, more scapular upward rotation in 90° and 135° humeral abduction and less scapulohumeral rhythm ratio in 45°, 90° and 135° humeral abduction than non-athletes in dominant shoulders. We suggest that clinicians should be aware that some scapular asymmetry may be common in some athletes. It should not be considered as a pathological sign but rather an adaptation to extensive use of upper limb.

A comparison of linear and nonlinear stability parameters in different clinical forms of multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is one of the neurological diseases that affect the ability of subjects to stand and walk. The stability of MS subjects has been evaluated in various studies, mostly based on linear approach. Based on this approach it is controversial weather stability of MS subjects differ from normal or not. Therefore, the aim of this study was to evaluate stability in three groups of MS subjects (spastic, ataxic and ataxic-spastic) using both linear and non-linear approaches. METHOD: Seventeen healthy and 36 subjects with MS participated in this study. The MS group presenting with spastic, ataxic and ataxic-spastic (each group consisted of 12 subjects) participated in the study. The stability of the subjects was evaluated using Kistler force plate. The difference between stability of the subjects was evaluated using the Multi Analysis of Variance and significant value was set at P < 0.05. RESULT: There was a significant difference in the mean value of Approximate Entropy (ApEn) in anterior-posterior direction between normal (0.66 ± 0.13) and ataxic (0.85 ± 0.12) and ataxic-spastic (0.90 ± 0.12) subjects (P < 0.05) and no difference between normal and spastic groups (0.76 ± 0.13). The results of both linear and nonlinear approaches confirmed that both ataxic and ataxic-spastic subjects had more instability than normal subjects. Although, the mean values of stability parameters increased in spastic compared to normal, the difference was not statistically significant. CONCLUSION: Subjects with ataxic and ataxic-spastic MS disorder had difficulty in controlling their stability during quiet standing. The results of this study also confirmed that spasticity of muscles surrounding the hip and knee joints did not influence standing stability in patients with spastic MS.

Efeitos de um tratamento combinado (vitamina C pré-exercício e alongamento FNP, tratamento com ultrassom pós-exercício) sobre marcadores de dano muscular induzido por exercício / The effects of a combination treatment (pre-exercise vitamin C & PNF stretching, post-exercise ultrasound treatment) on markers of exercise-induced muscle damage

CONTEXTO: Várias estratégias de recuperação têm sido utilizadas na tentativa de minimizar os sintomas da dor muscular de início tardio (DMIT). Contudo, evidências científicas que apoiem este efeito profilático (pré-exercício) e terapêutico (pós-exercício) de um tratamento combinado (FNP e vitamina C, ultrassom) no dano muscular são inexistentes. OBJETIVO: Investigar os efeitos de um tratamento combinado (FNP e vitamina C, ultrassom) nos marcadores bioquímicos (níveis enzimáticos) e funcionais (ângulo do cotovelo, circunferência de braço, taxa de dor) de dano muscular induzido por exercício. MÉTODO: Amostra randomizada controlada. LOCAL: Laboratório da Universidade. PARTICIPANTES: Alunos universitários masculinos participaram voluntariamente do estudo, o qual não reportou nenhuma dor muscular de início tardio por no mínimo seis meses antes do estudo. Posteriormente, os sujeitos foram agrupados aleatoriamente em subgrupos com mão controle e mão experimental. INTERVENÇÃO(ÕES): Programa de exercício para indução de dano muscular induzido por exercício envolvendo o teste de bíceps Scott (contração excêntrica com duas mãos). PROCEDIMENTO(S) PRINCIPAL(IS): Circunferência de braço relaxado, circunferência de braço flexionado, ângulo de cotovelo em descanso, circunferência de antebraço, amplitude de movimento de cotovelo flexionado, amplitude de movimento de cotovelo estendido, dano muscular induzido por exercício, força máxima voluntária isométrica e isocinética foram registrados basal, imediatamente após exercício e 24, 48, 72 e 96 horas após exercício. RESULTADOS: O subgrupo experimental manifestou redução de sintomas de DMIT em menor amplitude de movimento de cotovelo flexionado e amplitude de movimento de cotovelo estendido, menor perda de força isométrica e isocinética voluntária máxima (P < 0,05) em comparação com o subgrupo controle. Contudo, nenhum efeito na circunferência de braço relaxado, circunferência de braço flexionado, ângulo de cotovelo em descanso ou circunferência de antebraço foi observado (P >0,05). CONCLUSÃO: Este tratamento combinado foi eficiente em contração máxima voluntária isométrica, dor muscular de início tardio e taxa de intensidade de dor ao longo do tempo. Finalmente, os resultados sugerem que os tratamentos combinados são eficientes na manutenção de força isométrica e diminuição de dor muscular de início tardio e taxa de intensidade de dor.

CONTEXT: Numerous recovery strategies have been used in an attempt to minimize the symptoms of delayed-onset muscle soreness (DOMS). However, scientific evidence to support the effect of prophylactic (prior to exercise) and therapeutic (post-exercise) effects of a Combination Treatment (PNF & vitamin C, Ultrasound) on muscle damage is lacking. OBJECTIVE: To investigate the effects of a Combination Treatment (PNF& vitamin C, Ultrasound) on biochemical (enzymatic levels) and functional (elbow angle, arm circumference, pain rate, etc) markers of exercise-induced muscle damage. DESIGN: Randomized controlled trial. SETTING: University laboratory. PARTICIPANTS: non-athletic college-age men participated voluntary in this study, which reported no delayed onset muscle soreness for at least 6 months before, then subjects were randomly assigned to subgroups with control hand and experimental hand. INTERVENTION(S): Exercise program was used for induce exercise-induced muscle damage involved Preacher curl test (eccentric contraction in two hands). MAIN OUTCOME MEASURE(S): Relaxed arm circumference, flexed arm circumference, elbow resting angel, forearm circumference, range of motion flexed elbow, range of motion extended elbow, exercise-induced muscle damage, maximal voluntary isometric and isokinetic strength were recorded at baseline, immediately after exercise, and at 24, 48, 72 and 96 hours after post-exercise. Serum creatine kinase was measured at baseline, immediately after exercise, and at 24, 48, 72 and 96 hours post-exercise. RESULTS: The experimental subgroup showed a reduction in DOMS symptoms in the form of less range of motion flexed elbow and range of motion extended elbow, less maximal isometric and isokinetic voluntary strength loss(P <.05) compared with the control subgroup. However, no effect on relaxed arm circumference, flexed arm circumference, elbow resting angle, forearm circumference was evident (P >.05). CONCLUSION: This Combination Treatment on maximal voluntary isometric strength, delayed onset of muscle soreness and pain intensity rate during timing was effective. Eventually, results suggest that combination treatments are effective treatment on maintenance isometric strength and decrease of delayed onset of muscle soreness and pain intensity rate.

Acute effect of orthoses on foot orientation and perceived comfort in individuals with pes cavus during standing.

BACKGROUND: Changes in foot orientation due to orthoses and the relationship with perceived comfort are still unclear in pes cavus. The purpose of this study was to determine the acute changes of fore-foot angles due to the use of custom-made orthoses and their relationship with perceived comfort during standing. METHODS: Two photographs were taken using a color-coded camera-based system from the posterior and medial views of 20 subjects with bilateral pes cavus under barefoot and with orthoses conditions during standing. Djian-Annonier, calcaneal inclination, 1st metatarsal declination and rearfoot angles were measured and perceived comfort in the forefoot, midfoot and rearfoot was estimated using an adapted Visual Analogue Scale-type questionnaire. RESULTS: In comparison with the barefoot condition, orthoses increased significantly the 1st metatarsal declination angle by 1.9 degrees (p<0.01), and the Djian-Annonier angle by 1.1 degrees (p=0.02). The calcaneal inclination angle decreased significantly by an average of 3.0 degrees (p<0.01). Wearing orthoses significantly improved perceived comfort in forefoot, midfoot and rearfoot when compared to barefoot condition (p<0.01). A significant correlation was observed between variation of calcaneal inclination angle and the perceived comfort at the midfoot (r=-0.44; p=0.04). CONCLUSION: Flattening of foot arch and improvement of midfoot perceived comfort in pes cavus could be attributed to the reduction of the calcaneal inclination angle in the sagittal plane by using orthoses during standing.

Reliability of a computer-aided color-coded video-based system for clinical assessment of the foot.

UNLABELLED: There is a need for a user-friendly system that can provide quick and reliable assessment of foot disorders. The study described in this report was undertaken to determine the inter-rater and intra-rater reliability of a computer-aided, color-coded, video-based system developed for the assessment of foot alignment in patients with and without pes cavus deformity. Initially, 15 pedal angles were repetitively measured 7 times on 6 color-coded images of both feet, in 20 healthy adults. From the 7 repetitive measurements, the intra-class correlation was calculated and analysis of variance was used to estimate the minimum number of trials that would be necessary to identify a statistically significant difference in the measurements. To determine intra-rater reliability, 5 examiners evaluated a single set of data taken from 10 subjects. Additionally, data were obtained for 20 subjects with pes cavus deformity. The average intra-class correlation coefficient (ICC) for the anglular measurements for 2 to 7 trials was 0.98 +/- 0.06, while the intra-rater reliability was 0.90 +/- 0.14. No statistically significant differences were observed between right and left foot angles in able-bodied subjects; whereas, in the pes cavus group, 8 different angular measurements were observed to be statistically significantly different. The results of this investigation indicate that a computer-aided, color-coded, video-based system can be used to make reliable measurements of postural alignment in patients with and without pes cavus. LEVEL OF CLINICAL EVIDENCE: 5.