Journal of Sport Sciences and Health Research
Volume:2 Issue: 5, 2012

Balance is a key component of motor skills ranging from maintaining posture to executing complex sport skills. The aim of this study was to compare static and dynamic balance in athletes of gymnastic, soccer, basketball, swimming and nonathletes. 40 female athletes with five years of athletic experience (gymnasts: n=10, age 14.50±0.31 years, height 155.20±7.75 cm, mass 49.70±3.91 kg, soccer players: n=10, age 22.80±1.45 years, height 160.60±5.12cm, mass 52.95±4.87kg, basketball players: n=10, age 21.60±1.07 years, height 165.5± 6.75 cm, mass 57.43±6.27 kg), swimmers: n=10, age 23.30±1.63 years, height 163.5±5.46 cm, mass 55.50±4.42 kg) and 10 female non-athletes (n = 10, age 23.70±0.94 years, height 161.40±3.27 cm, mass 54.60±3.54 kg and without athletic experience) participated in this study. Static balance was assessed using the balance error scoring system (BESS) and dynamic balance was assessed using the star excursion balance test (SEBT). Data were analyzed by ANOVA test (p≤0.05). BESS error scores for the gymnastics group were significantly lower than the swimming group and nonathlete group. These scores in the soccer group were lower than swimming group (p≤0.05). Star excursion balance test scores were higher in the gymnastics group than the basketball group and non-athlete group and in the soccer group than nonathlete group (p≤0.05). It was observed that swimmers enjoyed lower static balance and basketball players enjoyed lower dynamic balance; this may be a strong predictor of future ankle sprains. Therefore, athletic trainers and coaches are advised to perform regular screening programs using balance test of BESS and SEBT, and to assess the athletes’ balance so that they can recognize those with poor balance.

Patellofemoral pain syndrome (PFPS) is one of the anatomical abnormalities and one of the most common knee problems, which causes anterior knee pain. Vastus medialis oblique (VMO) weakness and contracture of plantar flexors are among the most important factors to cause this syndrome. The purpose of the present study was to investigate the effect of concurrent planter flexor stretching and VMO strengthening in females with PFPS. 30 females (age 38.4±3.48 years, weight 70.5±2.89 kg) with PFPS participated in this study. Participants were randomly assigned to control and experimental groups. Experimental group received common medical treatment in addition to eight weeks of concurrent plantar flexor stretching and VMO strengthening exercises, while control group received only common medical treatment. The WOMAC questionnaire was administered to assess pain, physical dysfunction and stiffness. Also, range of motion of dorsiflexion, knee extension and Q angle were measured before and after the treatment. ANOVA with repeated measures was administered to analyze the data (P<0.05). The results after eight weeks of treatment showed a significant decrease in WOMAC score in both groups (compared to pretest) while the experimental group showed greater improvement. In the experimental group, range of motion of dorsiflexion increased significantly after eight weeks (P<0.05) (compared to pretest and control group). Also, Q angle decreased significantly in both groups (compared to pretest). Range of motion of knee extension increased significantly in both groups (compared to pretest) while experimental group gained more range of motion than control group. It can be concluded that concurrent planter flexor stretching and VMO strengthening may increase the efficiency of treatment of patients with PFPS.

Control of posture means to maintain limbs and body parts biomechanically which exists in static and dynamic forms. Dynamic posture is a condition in which body and its parts move during walking or running. Fatigue is one of the factors that influence posture control. Muscle fatigue can disturb sensory information received by brain and cause balance disorder. The purpose of the present investigation was to study the effect of quadriceps fatigue on dynamic balance control during walking. 30 volleyball players (15 males, 15 females, age 22.46+4.12 years, height 198.5+5.9cm, weight 60.2+9.7kg) participated in this study. Digital dynamometer was used to induce isometric quadriceps fatigue. Force platform was used to measure balance, displacement alteration, and the velocity of center of pressure as the balance parameters before and after the fatigue. ANOVA was administered to analyze the data (P<0.05). The results of this study showed that although the displacement of center of pressure in the frontal and sagittal planes increased after the fatigue, this difference was not statistically significant compared with pretest (P>0.05). After fatigue, the alteration of velocity of center of pressure decreased in frontal plane while it increased in sagittal plane, but the differences were not statistically significant (P<0.05). It can be concluded that no significant relationship existed between quadriceps fatigue with displacement alteration and velocity of center of pressure in frontal and sagittal planes; thus, quadriceps fatigue did not affect dynamic balance during walking.

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.

Down syndrome is most common genetic disorder with mild to moderate mental retardation and also a prevalence of 1 per 800-1000 births. The aim of this study was to assess static and dynamic balance in female students with and without Down syndrome and the relationship between balance with IQ and age. 30 mentally retarded students with Down syndrome (age 13.96±1.77 years, height 135.40±8.19cm, weight 42.86±9.21 kg, IQ 59.12±3.73) and 30 mentally retarded students without Down syndrome (age 14.30±1.96 years, height 136.30±8.07 cm, weight 41.46±8.67 kg, IQ 61.73±5.02) were selected randomly to participate in this study. Demographic data, height, weight and medical records of Down syndrome were collected from medical files. Modified single balance test to evaluate static balance and heel-to-toe test to evaluate dynamic balance were used. The result showed a significant difference between static and dynamic balance in two groups (p≤0.05). Also, a significant relationship was observed between dynamic and static balance with IQ and age in girls with Down syndrome (P≤0.05). People with Down syndrome have lower levels of kinetic growth in comparison with normal subjects and the mentally retarded people without Down syndrome and this fact causes weakness in their balance. Due to the weakness of balance in people with Down syndrome and also the importance of balance in daily activities and sport skills, it seems essential to design and perform physical programs to improve their balance.