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Background and Objective: 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.
Methods: 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.
Results: 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).
Conclusion: Knee brace did not change running economy. However, the using of brace 15 degree improved general knee joint co-contraction during loading phase.

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Background and Objective: Inactivity and physical inactivity can be one of the main causes of obesity, especially abdominal obesity, hypertension, cardiovascular disease. Abdominal obesity is a serious risk factor for cardiovascular disease which being inversely related to VO₂ max (maximal oxygen consumption). This study was done to determine the non-invasive monitoring of cardiorespiratory fitness and its association with abdominal obesity in men.
Methods: In this descriptive-analytical study, men aged 20-60 years were selected by cluster sampling from different areas of the centers of the three provinces including Qazvin, East Azarbajan and Hamedan in Iran. In accordance with Morgan method, the sample size was 384 men from all provinces which were divided into four age groups. Aerobic power of subjects was assessed by utilizing Bruce, Rockport, Pedometer and International Physical Activity Questionnaire (IPAQ). Waist-to-height ratio (WHtR), Waist-to-hip ratio (WHR), Body adiposity index (BAI), Surface-Based Body Shape Index (SBSI) and body mass index (BMI) was measured for each subject.
Results: Based on the results, in all three provinces as well as the provinces themselves, VO₂ max was significantly different between different age groups (P<0.05). Also, in abdominal obesity indices, a significant difference was in abdominal obesity indices BMI, WHR, WHtR and BAI (P<0.05). There was a significant inverse correlation of the VO₂ max with central obesity indices, except for the SBSI.
Conclusion: Reducing physical activity and consequent cardiorespiratory fitness led to an increase in abdominal obesity indices in different age groups that shows a significant inverse correlation of the VO₂ max with central obesity indices, except for the SBSI.