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Frequently we find that orthotic shoe inserts are prescribed for athletes allegedly suffering from some sort of muscle imbalance, skeletal imbalance or faulty running mechanics. Are such devices always helpful and rarely harmful to the non-pathological athlete? The following studies address these issues. Any comments about the use of orthotics in non-pathological situations? ----------------- Clin Biomech (Bristol, Avon) 2000 Jan;15(1):54-64 Effects of foot orthoses on skeletal motion during running. Stacoff A, Reinschmidt C, Nigg BM, van den Bogert AJ, Lundberg A, Denoth J, Stussi E. 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 (up to 10 degrees) than between the orthotic conditions (1-4 degrees ). Significant orthotic effects across subjects were found only for total internal tibial rotation). 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. -------------- Arch Phys Med Rehabil 1999 May; 80(5):540-4 Electromyographic effects of foot orthotics on selected lower extremity muscles during running. Nawoczenski DA, Ludewig PM. 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 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' EMG 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. ------------- J Orthop Sports Phys Ther 1993 Oct;18(4):532-6 The effects of foot orthotics on the EMG activity of selected leg muscles during gait. Tomaro J, Burdett RG. 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 non-independent 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. ----------------- Phys Ther 1994 Sep;74(9):836-44 The effect of soft foot orthotics on three-dimensional lower-limb kinematics during walking and running. Eng JJ, Pierrynowski MR. BACKGROUND AND PURPOSE. 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. SUBJECTS. 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. METHODS. 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). RESULTS. 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. CONCLUSIONS AND DISCUSSION. 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. --------------- J Orthop Sports Phys Ther 2000 Nov;30(11):664-75 Effect of foot orthotics on calcaneal eversion during standing and treadmill walking for subjects with abnormal pronation. Genova JM, Gross MT. STUDY DESIGN: Repeated measures analysis of intervention. OBJECTIVES: To de termine the effects of foot orthotics and shoewear on calcaneal eversion for standing and treadmill walking. BACKGROUND: Foot orthotics are commonly used as an intervention for treating lower extremity musculoskeletal pathology. Qualitative research regarding the benefit of foot orthotics tends to be favorable, while the results of quantitative studies often conflict. METHODS AND MEASURES: Eight men (mean age = 35.8 +/- 12.7 years) and 5 women (mean age = 30.4 +/- 10.6 years), who demonstrated abnormal pronation, walked quickly (average velocity = 1.9 m/s) on a treadmill with and without foot orthotics. Subjects were filmed using a 2-dimensional video system and plastic molds designed to indicate calcaneal position inside the shoe during static standing and treadmill walking. RESULTS: Paired t tests indicated that foot orthotics significantly reduced the mean maximum calcaneal eversion angle by 2.2 degrees and the mean calcaneal eversion angle at heel rise by 2.1 degrees during fast walking. Orthotic and nonorthotic conditions did not differ significantly for the remaining kinematic variables. A one-way ANOVA indicated that calcaneal eversion in standing was significantly greater for barefoot standing compared with standing in shoes with or without orthotics. ANOVA also indicated that the plastic molds provided reliable measures of calcaneal position. CONCLUSIONS: Foot orthotics have a significant effect on calcaneal eversion and shoes also should be considered in conjunction with foot orthotic prescription. ------------ Dr Mel C Siff Denver, USA http://groups.yahoo.com/group/Supertraining/