1. Introduction
ostural control is defined as the control of body position in space to maintain body stability and orientation. Postural orientation is the ability to maintain a proper connection between body segments as well as between the body and the environment to perform a task. In many functional tasks, body alignment is vertical.
Furthermore, to maintain this state, it applies various sensory stimuli, such as gravity (vestibular system), the base of support (somatosensory system), and the body’s relationship to objects in the environment (visual system). The lower extremity, due to its significant role in enduring weight, absorbing and modifying the pressures and kicks during dynamic activities (e.g. walking, running, jumping), and maintaining the postural control in standing and moving positions, is of particular importance [2]. The knee joint plays a significant role in supporting the body and transmitting its weight during static and dynamic activities; however, since it has almost no bone component to stabilize it, it is one of the most vulnerable joints in the lower extremity [3].
Genu varum is among the knee deformities [4]. Such changes in the lower limb can disturb the center of gravity relative to the base of support; they might ultimately cause significant changes in individuals’ balance. The mechanical axis of the knee usually passes through the center of the knee joint, i.e. from the tubercle between the tibial condyle, and when standing on two legs, the force is equally distributed between the inner and outer knee parts [5]. Genu varum deformity affects the mechanical axis deviation of the knee joint. Moreover, internal and external ankle rotation influences the mechanical axis deviation of the ankle joint. Therefore, the mechanical axis deviation of the lower extremity joints could significantly impact on the forces exerted by the ground as well as balance disturbance [6]. Researchers disregarded investigating the effects of genu varum deformity on the balance of athletes at younger ages. Thus, this study aimed to investigate the static and dynamic balance of adolescent athletes with and without genu varum deformity.
2. Participants and Methods
A total of 580 adolescent male athletes aged 11-14 years in Marivan County, Iran, were screened for genu varum deformity using a caliper. Of them, 42 with and without genu varum were purposively selected as the study samples. The study participants were divided into 2 groups of 21.
To detect genu varum, the subject stood bare feet on both legs without any contractions and abnormal tonicity in the thigh muscles. The knees were in full extension and the ankles stick together where the patella bones were facing forward. In this state, the distance between the two medial femoral condyles was measured by a caliper. A distance of ˃3 cm between the two condyles was considered as a genu varum [5]. The Bass Stick test was used to measure the static balance of the study subjects [14]. Besides, the Y Balance Test (YBT) was used to evaluate the dynamic balance [15, 16].
3. Results
Table 1 presents Mean±SD values of the study variables. The t-test results (Table 2) suggested no significant difference in static balance between the study subjects with and without genu varum. Moreover, the results dynamic balance test in anterior direction revealed no significant difference between the study groups; however, group differences were significant in posterolateral (t=3.15, P=0.004) and posteromedial (t=3.17, P=0.003) directions. In other words, the study subjects with genu varum had less dynamic balance in lateral posterior and medial posterior directions, compared to their healthy counterparts.
4. Discussion
In this study, no statistically significant difference was found in the static balance between the study subjects with genu varum and healthy controls. This could be because the sport has a dynamic nature, rather than a static one; thus, it did not affect the static balance of subjects. In dynamic balance, the difference between the two study groups was only significant in the anterior direction. In other words, athletes with genu varum had less dynamic balance than their healthy peers in lateral posterior and medial posterior directions. The obtained static balance test data was in line with some other studies. Shojaedin et al. [10] investigated the relationship between varus knee deformity and dynamic and static postural control in 10-12-year-old boys. Their results indicated that varus knee deformity did not affect the samples’ static balance.
5. Conclusion
Varus knee deformity could affect the dynamic balance of athletes compared to their healthy counterparts. The adverse effects of such deformities on balance increases with aging. It is recommended that this study be conducted with a larger sample size as well as a more extensive age population range to be able to generalize the findings to different groups.
Ethical Considerations
Compliance with ethical guidelines
Prior to the study, a brief explanation of the tests and methods were given to the participants. Then, a written informed consent was obtained from their parents and they were told that they were to leave the study at any time. Moreover, permissions were obtained from the Department of Youth Affairs and Sports in Marivan, Iran.
Funding
This research did not receive any financial support from funding agencies in the public, commercial, or not-for-profit organizations.
Authors' contributions
Investigation and draft preparation: Reza Hosseini; review and editing: Ali Asghar Norasteh and Nezam Nemati.
Conflicts of interest
The authors declare no conflict of interest.

References