The Effect of the Fatigue in Lower Extremity Proximal and Distal Muscles on Dynamic Balance in Male Soccer Players

Regarding the relationship between muscle fatigue resulted from sport activities and
dynamic balance, the purpose of this study was to examine the effect of proximal and
distal muscle fatigue of lower extremity on dynamic balance of male soccer players. 20
male physical education students (the mean and standard deviation of age: 20.24?0.73
yrs, height 170.27?4.28 cm, weight 67.38?9.24 kg and body mass index (BMI)
23.22?2.02 kg/m2, without any lower extremity injury or orthopedic problem) from
Tehran Tarbiat Moallem University who participated three times per week in the
exercise program of the university soccer team voluntarily participated in this study. In
order to estimate the participants’ dynamic balance, after a short warm-up (5-10 minutes
of stretching and slow running), (SEBT) balance test was applied. Dynamometer
Isokinetic Biodex System was used to execute proximal and distal muscle fatigue in lower
extremity. Each subject participated in four muscle fatigue sessions. The fatigue program
was randomly executed with respect to location and plane motion to one of the muscle
groups of plantar/dorsiflexors and evertor/inventors of ankle joint and flexor/extensors
and abductor/adductors of hip joint. Repeated contractions until reaching 50% of
primary maximum torque with an interval of 72 hours and in the same situation as far as
possible were performed. After fatigue program, SEBT posttest was applied. Descriptive
statistics, correlated t test and analysis of variance (repeated measures) were used for
statistical analysis (P?0.05). The results showed that the isokinetic fatigue of proximal
and distal muscles of lower extremity significantly decreased accessible distance in SEBT
test. Furthermore, fatigue in the muscles of hip joints significantly decreased accessible
distance compared to the muscles of ankle joints. It can be concluded that the fatigue of
proximal muscles in lower extremity was more effective in the dynamic balance of soccer
players compared to the distal muscles.