فهرست مطالب سعید نوری نسب

Genu valgus malalignment is associated with altered lower limb muscular activities during running. The study aimed to evaluate the effect of using a brace in three different knee flexion angles on the frequency of muscular activity during running in people with genu varus.

The statistical sample of this study consisted of 30 soccer students. Fifteen persons with genu varus and 15 healthy persons were selected to participate in this study. The electrical activity of the muscles, including medial gastrocnemius, tibialis anterior, vastus medialis, rectus femoris, vastus lateralis, biceps femoris, and semitendinosus, were recorded by electromyography system during running with four brace conditions (without a brace, knee brace at 15˚, 30˚, and 60˚ knee flexion).

The results showed that the main effect of “brace” on the frequency spectrum of the biceps femoris during the loading phase was increased statistically. During the loading phase, the most significant median frequency of the biceps femoris was running with a brace with 30˚ knee flexion. The main effect of “brace” on the frequency spectrum of semitendinosus during the push-off phase was statistically significant. The lowest value of semitendinosus muscle was during running with a brace with 15˚ knee flexion.

The most significant effect of a knee flexor brace is on the frequency content of biceps femoris and semitendinosus muscles with a mount at 30˚ knee flexion. This may be due to the passive support role of the brace and possibly could prevent biceps femoris and semitendinosus injuries.

Genu varus is a deformity in frontal plane that in weight bearing position whiles the medial malleolus’s touch each other, the medial knee epicondyles far from each other. Genu varus is very prevalent in soccer players. This study was done to evaluate the effect of using knee brace and lateral wedge on muscular activity amplitude in male soccer players with genu varus during running.

This quasi-experimental study was done on 15 right-footed male soccer players with genu varus and 15 healthy soccer players. A wireless electromyography system with eight pairs of bipolar Ag/AgCl surface electrodes (20 mm center-to-center distance; input impedance of 100 MΩ; and common-mode rejection ratio of >110 dB) was used to record the activity of the tibialis anterior, gastrocnemius medialis, biceps femoris, semitendinosus, vastus lateralis, vastus medialis, and rectus femoris, and gluteus medius muscles of the right leg. Electromyography data were recorded by sampling rate of 1000 Hz in selected muscles during running at five conditions including: control, 10 degrees lateral wedge, 15 degrees lateral wedge, simultaneous using 30 degrees brace and 10 degrees lateral wedge, and simultaneous using 30 degree brace and 15 degrees lateral wedge.

Treatment intervention had reduction effect on muscular amplitude of biceps femoris and vastus lateralis during push-off phase (P<0.05). Muscular amplitude of biceps femoris and vastus lateralis during loading phase was reduced due to Treatment intervention (P<0.05).

Simultaneous using of lateral wedge and knee brace reduce the electromyography activity of vastus lateralis and biceps femoris muscles. This reduction may be associated with passive support of knee brace that in result could decrease the external knee adductor mowment.

Genu varus deformity is associated with changes of lower limb muscle co-contraction and running economy. This study was done to evaluate the effect of using of brace in three different knee flexion angles on running economy and lower limb muscular co-contraction in individuals with genu varus.

This quasi-experimental study was done on active soccer male students including 15 healthy subjects (average age of 22.86±1.55 years) and 15 subjects with genu varus (average age of 22.13±1.80 years). The amount of electrical activity of the muscles (tibialis anterior, medial gastrocnemius, vastus medialis, vastus lateralis, rectus femoris, biceps femoris, semi-tendinosus) were recorded by electromyography system during four conditions of with and without using knee brace. After that, directed and general co-contraction was computed during running. The angles of brace were 15, 30, and 60 degrees. The values of VO2 max were recorded using of gas analyzer system to compute running economy.

The ratio of respiratory exchange was significantly more in the genu varus group than healthy group (P<0.05). However, the acute effect of brace was not significant on running economy and ratio of respiratory exchange. The main effect of brace was significant for general co-contraction of knee joint during the loading phase (P<0.05). Paired wise comparison revealed significant greater general knee co-contraction during brace conditions (P<0.05). However, the general knee co-contraction during loading phase reduced while using brace 15 degree. The main effect of “brace” for ankle joint general co-contraction during the push-off phase was significant (P<0.05). Paired wise comparison revealed significant greater general ankle co-contraction during brace conditions at push-off phase (P<0.05).

Knee brace did not change running economy. However, the using of brace 15 degree improved general knee joint co-contraction during loading phase.