Orthotic Conditions Research Articles

Effects of foot orthoses on skeletal motion during running

Objective. To quantify the effects of medial foot orthoses on skeletal movements of the calcaneus and tibia during the stance phase in running. Design. Kinematic effects of medial foot orthoses (anterior, posterior, no support) were tested using skeletal (and shoe) markers at the calcaneus and tibia. Background. Previous studies using shoe and skin markers concluded that medially placed orthoses control/reduce foot eversion and tibial rotation. However, it is currently unknown if such orthoses also affect skeletal motion at the lower extremities. Methods. Intracortical Hofman pins with reflective marker triads were inserted under standard local anesthetic into the calcaneus and tibia of five healthy male subjects. The three-dimensional tibiocalcaneal rotations were determined using a joint coordinate system approach. Eversion (skeletal and shoe) and tibial rotation were calculated to study the foot orthoses effects. Results. Orthotic effects on eversion and tibial rotations were found to be small and unsystematic over all subjects. Differences between the subjects were significantly larger ( p < 0.01; up to 10°) than between the orthotic conditions (1–4°). Significant orthotic effects across subjects were found only for total internal tibial rotation; p < 0.05). Conclusions. This in vivo study showed that medially placed foot orthoses did not change tibiocalcaneal movement patterns substantially during the stance phase of running. Relevance Orthoses may have only small kinematic effects on the calcaneus and tibia (measured with bone pins) as well as on the shoes (measured with shoe markers) during running of normal subjects. Present results showed that orthotic effects were subject specific and unsystematic across conditions. It is speculated that orthotic effects during the stance phase of running may be mechanical as well as proprioceptive.

Stance balance control with orthoses in a group of children with spastic cerebral palsy

Although ankle‐foot orthoses (AFOs) are frequently prescribed to correct skeletal malalignment in children with spastic diplegia, their effect on standing balance abilities has not been documented. This study investigated balance differences related to the presence of pathology and orthotic conditions during conditions of unexpected stance perturbation by comparing four children aged between 3 and 15 years with spastic cerebral palsy and four control children matched for years of independent walking experience. Electromyographic and kinematic data were collected and compared between groups and in three orthotic conditions (no AFOs, solid AFOs, dynamic AFOs). Results revealed that balance responses of children with spasticity were characterized by: increased coactivation of muscles as opposed to distal to proximal recruitment, decreased presence of upright posture in stance, increased use of‘on‐toes’strategies, and different sway characteristics compared with the typically developing children. In both groups of children, the use of solid AFOs during perturbed stance resulted in: decreased activation of gastrocnemius muscles, disorganized muscle‐response patterns, decreased use of ankle strategies, and increased joint angular velocities at the knee compared with conditions without AFOs or with dynamic AFOs. These preliminary results support the use of dynamic AFOs to correct skeletal malalignment in children with spastic diplegia.

Electromyographic effects of foot orthotics on selected lower extremity muscles during running

Objective: To study the effects of foot orthotics on the mean electromyographic amplitude of proximal and distal lower extremity muscle groups during the first 50% of the stance phase during treadmill running. Design: Repeated measures. Setting: Subjects were recruited from the general community. Participants: Twelve recreational runners who were symptomatic for lower extremity pain. Clinical and radiographic findings confirmed the presence of structural malalignment of the foot. Intervention: Semirigid orthotics were fabricated for each subject, and like footwear provided. Main Outcome Measures: Surface electromyogram activity from the tibialis anterior, medial gastrocnemius, vastus medialis, vastus lateralis, and biceps femoris was collected during treadmill running at self-selected speeds for orthotic and nonorthotic conditions. Root mean square values were averaged across 10 cycles, normalized to time and expressed as a percentage of the nonorthotic condition. Results: Paired t test results showed statistically significant changes ( p < .05) for the biceps femoris (−11.1%) and tibialis anterior (+37.5%) muscle groups during the orthotic condition. Electromyographic activity in the medial gastrocnemius, vastus medialis, and vastus lateralis with orthotic use was not significantly different from the nonorthotic condition. Conclusion: Although subjects' electromyographic responses to orthotic use were highly individualized, the findings of this study may enhance our understanding of muscle activity changes associated with positive outcomes from orthotic use.

The effect of use of a wrist orthosis during functional activities on surface electromyography of the wrist extensors in normal subjects

Wrist orthoses are advocated for patients with lateral epicondylitis on the assumption that use of the orthosis decreases muscle activity of the wrist extensors during activities. The purpose of this study was to compare the amount of electrical activity, root mean square (RMS) calculated from surface EMG recorded over the wrist extensors, during activities when applying four conditions of wrist orthoses: dorsal; volar; semicircular; and no orthosis. Thirteen normal subjects (mean age 27.7 years) performed three lifting and two gripping tasks, repeated on three consecutive days under four orthotic conditions. Measured were RMS and maximum voluntary grip strength. Repeated measures ANOVA's indicated a significant decrease of RMS using the semicircular design during lifting (p < .0005). Grip strength decreased significantly using all three orthotic designs, but RMS recorded during gripping did not. It was concluded that application of a wrist orthosis reduces electrical activity of the wrist extensors less than anticipated and only during lifting.

The effect of foot orthotics on the initiation of plantar surface loading

INTRODUCTION:: Little information exits concerning the effect, if any, foot orthoses have upon how the foot is loaded during normal walking. The purpose of this study was to determine if there was a difference in the initiation of forefoot loading with different densities of foot orthoses. METHODS:: Ten volunteers (5 men, 5 women) between the age of 23 and 43 years (mean=30.3 yrs) participated in this study. None of the subjects had a history of congenital deformity, hallux valgus, malleolar torsion or a history of injury or pain to either lower extremity 12 months prior to the start of the investigation. Two different pair of foot orthoses were provided to each subject in the study. One pair consisted of UCO-BKS medium width foot orthoses with a durometer rating of 55-60 (Shore A gauge). Forefoot and/or rearfoot wedging was applied to these orthoses if indicated from a physical examination. This orthotic condition was labeled RIGID. The second pair consisted of UCO-BF foot orthoses with a durometer rating of 30-35 (Shore A gauge). This orthotic condition was labeled SOFT. In addition to the foot orthoses, each of the 10 subjects were fitted with the same type of footwear (Reebok Boston Road). Following a 'break-in' period for the footwear and orthotics, each subject walked along a 12 m walkway with the EMED PEDAR insole placed inside their shoes. A total of 10 consecutive walking trials were collected at each subject's self-selected speed. Using the NOVELWin MASKS program, the plantar surface of the forefoot was divided into 3 different areas, Lateral, Central and Medial. The time of initiation of loading for each of these masks was then determined. Reliability of the loading initiation times was determined using type (2,1) intraclass correlation coefficients. Differences between the three forefoot areas were determined using a one-way, repeated measuresANOVA and Tukey's post hoc analysis, if indicated. An alpha level of 0.05 was used for all tests of statistical significance. RESULTS:: The ICC values for the initiation of loading in the forefoot were in excess of.936. The result of theANOVA test revealed that the medial forefoot is loaded significantly earlier with a RIGID foot orthotic compared to either the SHOE ONLY or SOFT foot orthotic condition. This earlier loading caused a reversal of the normal loading sequence of plantar pressure in the forefoot during walking. DISCUSSION:: Previous studies have reported that approximately 10 degrees of forefoot movement, independent to hindfoot motion occurs during the loading response of walking. An additional 3 degrees has been shown to occur from the end of the loading response to mid-stance. It would appear from the findings of this study that rigid orthoses prevent this normal independent movement between the forefoot and hindfoot, since the rigid orthoses cause earlier loading of the medial forefoot. The soft orthoses permitted the same lateral to medial forefoot loading pattern also observed in barefoot walking. CONCLUSION:: The results of this study indicate that the use of a rigid foot orthosis inside a shoe, alters the timing of forefoot loading during walking. These findings suggest that the use of soft orthoses permit a more normal forefoot to hindfoot movement pattern during the loading phase of walking.

Footwear and foot orthotic effectiveness research: a new approach.

Measurement of calcaneal inversion and eversion during walking is limited when subjects wear shoes. The authors of this study propose the use of transverse tibial rotation as a viable alternative measurement when barefoot assessment is not possible. The purpose of this study, therefore, was to: 1) determine the relationship between transverse tibial rotation and rearfoot motion during the stance phase of normal walking and 2) demonstrate the usefulness of measuring transverse tibial rotation when evaluating the effect of footwear and insole foot orthotic devices. Part 1 consisted of eight volunteers (five women, three men) whose rearfoot and transverse tibial motion was videotaped while they walked along a 12-m walkway. The results of this study showed that although absolute values were not comparable, the two motion patterns are related to each other. The correlation between the mean rearfoot and tibial motion patterns of all 16 feet was r = .953. Part 2 investigated the effect of footwear and orthotics on transverse tibial rotation using two case presentations. A video camera was positioned in front of each subject as they walked at a self-selected speed under various footwear or orthotic conditions. The results of the case studies revealed that footwear or foot orthotics decrease maximum tibial internal rotation compared with barefoot walking. In addition, internal tibial rotation velocity and acceleration were decreased by the use of shoes, an accommodative orthosis, and an inflatable medial longitudinal arch support. A rigid orthotic produced a slight increase in transverse tibial rotation and a dramatic increase in transverse tibial acceleration.(ABSTRACT TRUNCATED AT 250 WORDS)

The Effect of Soft Foot Orthotics on Three-dimensional Lower-Limb Kinematics During Walking and Running

Although foot orthotics are often prescribed to alter the lower-extremity mechanics during the stance period of gait, there is little documentation of the actual effect of foot orthotics on the movement of the lower-extremity joints during walking and running. This study examined the effect of foot orthotics on the range of motion of the talocrural/subtalar joint and the knee joint in three dimensions during walking and running. Ten female adolescent subjects, aged 13 to 17 years (X = 14.4, SD = 1.1) who were diagnosed with patellofemoral pain syndrome and exhibited forefoot varus greater than 6 degrees and/or calcaneal valgus greater than 6 degrees participated in the study. Thirty strides of walking and running on a treadmill were recorded for each of the orthotic and nonorthotic conditions for each subject using an optoelectronic recording technique. Analyses of variance for repeated measures were performed on the range of motion of the talocrural/subtalar joint and knee joint for each plane of motion (ie, six separate analyses). The main factors of each analysis were the effect of the orthotic (orthotic condition versus nonorthotic condition), mode of ambulation (walking and running), and phase of the stance period (contact, mid-stance, and propulsion). No differences were found in sagittal-plane movements. Reductions of 1 to 3 degrees occurred with orthotic use for the talocrural/subtalar joint during walking and running in the frontal and transverse planes. The orthotics reduced knee motion in the frontal plane during the contact and mid-stance phases of walking, but increased the motion during the contact and mid-stance phases of running. This study shows that corrections to the static position of forefoot varus and calcaneal valgus can result in changes in transverse- and frontal-plane motion of the foot and knee during walking and running.

The effects of foot orthotics on the EMG activity of selected leg muscles during gait.

Foot orthotics have been successfully used to treat muscular overuse leg injuries in athletes. The purpose of this study was to examine the effects of foot orthotics on the electromyographic (EMG) activity of the tibialis anterior, peroneus longus, and gastrocnemius muscles during walking. Ten volunteers with leg symptoms resulting from compensatory subtalar joint pronation were fitted with foot orthotics. The duration of tibialis anterior EMG activity following heel strike and the average EMG activity of the tibialis anterior, peroneus longus, and gastrocnemius muscles were collected with surface electrodes. Comparisons were made between the orthotic and nonorthotic conditions. A t-test for nonindependent samples with a significance level of p < 0.05 was used for data analysis. There was a statistically significant increase in the duration of tibialis anterior activity following heel strike in the orthotic condition. There were no significant differences in the average EMG activity for any of the three muscles between the orthotic and the nonorthotic conditions. This study suggests that foot orthotics had minimal effects on the muscles studied and that further research is necessary to determine the effectiveness of orthotics on the EMG activity of other leg muscles.

A 3-D model of the lower limb in a cycling movement

Objective. To investigate the influence of a custom foot orthotic intervention on the lower extremity dynamics in healthy runners.Design. Three-dimensional kinematics and kinetics were collected on 15 female runners (>15 miles per week) while each performed the over-ground running trials in either a shoe only or a shoe + custom foot orthotic condition. Kinematic and kinetic variables were analyzed using Paired Sample t-tests.Background. Custom foot orthotics are frequently prescribed treatment modality for the management of overuse running injuries. Although it is generally accepted that a custom foot orthotic intervention produces positive clinical outcomes, it remains unclear what influence this therapeutic modality has on the dynamics of the lower extremity.Methods. Each subject performed five acceptable over-ground running trials (3.6 m s−1 ±5%) with and without the custom foot orthotic intervention in a running shoe. Selected maximum ankle and knee joint angles and moments were measured during the stance phase.Results. While wearing the custom foot orthotic, subjects exhibited significantly decreased maximum values in rearfoot eversion angle, rearfoot eversion velocity and internal ankle inversion moment.Conclusions. In this sample of healthy female runners, the custom foot orthotic intervention led to significant decreases in maximum values for ankle dynamics in the frontal plane and in the sagittal plane of the knee joint.Relevance It remains unclear how a custom foot orthotic intervention influences lower extremity dynamics to produce positive clinical outcomes. Furthering our understanding of the dynamic influence will not only inform improved prescription and manufacturing practices but may provide insight into the mechanisms that cause overuse injuries.