Research in Sport Medicine and Technology

The aim of this study was to investigate the effect of functional fatigue on the dynamic and static balance of male students aged 15 to 18 with different plantar arch. To measure the subjects' foot arch, the Navicular Drop Test was used. The subjects were then randomly divided into three groups of 22 members with different foot arches. Later on, SEBT test, Modified Stork Balance, Fatigue Protocol and Borg (RPE) scale were run. Using SPSS (version 18), the data were analyzed (p< .05); in particular, dependent t-tests, One-way ANOVA and Scheffe's post hoc test were run. The results showed a significant difference between pre-test and post-test scores of dynamic and static balance in all three groups. Scheffe's post hoc test revealed that there was a significant difference between the mean difference of pre-test and post-test scores of the dynamic and static balance group of normal foot arch, the flat foot arch group and the cavus foot arch group. Meanwhile, the difference between flat and cavus foot group was not statistically significant. Due to the significant reduction in the balance of subjects with abnormal arch, the correction of the abnormality of the foot arch as well as the use of appropriate training courses are recommended to improve their physical fitness.

One of the factors affecting jump-landing patterns is fatigue. Fatigue is an inevitable component of physical
activity, hence the aim of the present study was to investigate the effect of functional fatigue on landing
mechanics through Landing Error Scoring System (LESS).Fourteen male college students with a mean age of
22±2 years, weight of 68.3±7.2 kg and height of 174±4 were randomly divided into two groups: experimental and
control. Effect of independent variable, fatigue, due to activities resembling athletic training or competition (6-
stations functional fatigue protocol) on dependent variable, landing mechanics, through pre test-post test was
investigated. The independent t-tests and non-parametric U-Mann Whitney test was used for statistical analysis
of data (P < 0.05). The results of the present study indicated the relationship between fatigue and attenuation of
landing mechanics (P=0.02), and therefore an increase in injury risk. Also it was shown that the effect of fatigue
on decreasing knee flexion angle at initial contact was significant (P=0.022). With regard to the results, it can be
concluded that functional fatigue induced by physical activities can alter landing mechanics, and increase loading
of lower extremity joints, particularly the knee. So the risk of injury in these joints may be increased.

The purpose of this study was to investigate the effect of soccer specific functional fatigue on hip and knee
joints angles during landing in professional players.15 soccer players with at least 2 years experience in
Kerman soccer clubs were selected randomly. To evaluate the lower extremity kinematics following
jumping and soccer specific- heading, three cameras (with50Hz) were used. To cause fatigue in subjects,
specific functional protocol similar to specific bangsbo soccer was used and Quantic sport v21 soft ware
was administrated for kinematic analysis of the recorded films. To statistical analyzing of data, descriptive
statistical methods, and paired-t test were administrated at α=0.05.Finding revealed that hip and knee
angles in sagittal and frontal plane in landing is influenced by functional fatigue. This results has been
reducing knee and hip flexion angles and increased varus in knee joint. Results demonstrated a more
erect landing posture due to a decrease in hip and knee flexion angles in the post fatigue condition.
However, functional fatigue significantly decrease lower extremity control ability in male soccer player
during landing.