Journal of Sport Sciences and Health Research
Volume:6 Issue: 12, 2014

Low back injuries account for 10-15% of all athletic injuries. It is difficult to design an exercise program to prevent and rehabilitate low back injury without knowing the differences in the kinematics and spinal loads in the sports techniques and the physical characteristics associated with low back pain (LBP). The aim of this study was to compare strength، endurance and range of motion of lumbar spine in athletes with and without LBP. 15 male athletes (mean age 21. 35+3. 7 yr، height 177+8. 44 cm and weight 72. 8+6. 3 kg) without any history of LBP were matched by age and handicap to 15 male athletes (mean age 21. 8+2. 34 yr، height 173. 6+6. 38 cm and weight 70. 65+8. 18 kg) with a history of non-specific LBP. The subjects voluntarily participated in this study. An Oswestry and Quebec questionnaire was used to determine handicap and severity of low back pain. A spinal mouse device was used to determine lumbar range of motion، and Nicholas manual muscle tester (MMT) was used to assess muscular strength of lumbar muscles، and Ito endurance tests was used to measure lumbar muscular endurance. The LBP athletes significantly demonstrated less lumbar extension muscle endurance (P=0. 016) and less lumbar extension range of motion (P=0. 05). No significant differences were found in lumbar flexor endurance، lumbar flexors and extensors muscular strength and lumbar flexion range of motion (P>0. 05). Although differences found in this study cannot be determined as causes or results of low back injuries in athletes، clinicians may be able to design a more appropriate exercise program for athletes to prevent or rehabilitate low back injury based on these findings.

Anterior cruciate ligament (ACL) injury is one of the commonest injuries in athletes as about 80% of all surgeries performed on the knee ligaments are allocated to ACL. The aim of this study was to investigate the effect of a rehabilitation period on muscle torque، proprioception and range of motion after ACL reconstruction. 9 male athletes (mean age 28. 77±5. 2 years) who had ACL reconstruction surgery using a hamstring graft participated in this study as the sample. After physiotherapy، muscle torque and proprioception were measured using the Biodex isokinetic dynamometer (system 3) and range of motion was assessed by manual goniometer. Paired samples t test was used to analyze the data. The results of this study showed that the injured knee of patients had significantly lower mean torque in extensor than the uninjured knee (P≤0. 05). No significant difference was observed in range of motion between the injured and uninjured knee (P≥0. 05). Only one patient had higher error of proprioception in the injured knee than uninjured knee. Although the patients had lower error of proprioception in their injured knee، no significant difference was observed (P≥0. 05). It can be concluded that although rehabilitation after ACL surgery was not able to improve strength in the injured knee، it could improve range of motion and proprioception in knee joint.

The aim of this study was to assess the activity of scapular muscles in subjects with forward head posture. The statistical population consisted of female students living in University of Tehran dormitories. 14 healthy girls and 18 girls with forward head posture aged between 23 and 30 were selected. The electromyography activity of serratus anterior، upper trapezius and lower trapezius were recorded during arm abduction. To normalize the data، the mean square of level of electromyography of each muscle was divided by the mean square of level of isometric contraction. Independent t test was used to compare the results in the two groups. The results showed that the electric activity of upper trapezius (P=0. 002) in subjects with forward head posture was higher than the healthy group while lower trapezius and serratus anterior showed no difference between the groups. The results showed a difference in electromyography activity of upper trapezius during arm abduction between the healthy group and forward head group. Thus، it can be concluded that normal head posture during arm abduction can support the biomechanical head posture to reduce excessive activity of the upper trapezius.

The aim of the present study was to determine the effect of resistance training on static and dynamic balance in healthy elderly men. 24 healthy elderly men with no experience of falling were divided into resistance training (RT) group (n=12، mean age: 59. 2±6. 96 years، weight: 74. 5 ±5. 3 kg، height 172. 41±6. 2 cm) and control group (n=12، mean age: 63. 6±5. 68 years، weight: 77. 6±7 kg، height: 173. 4±7. 3 cm). Static balance was measured with open and closed eyes by Sharpened Romberg (reliability: open eyes 0. 90-0. 91 and closed eyes 0. 76-0. 77) and dynamic balance by timed get up and go test (reliability 0. 99) before and after the intervention. RT group performed strength training for 8 muscle groups twice a week for 8 weeks while control group had their daily routine. To determine the difference between pretest and posttest of the groups، ANOVA with repeated measures was used at P≤0. 05. Data analysis was completed using the statistical software SPSS v. 16. The results showed that although strength training changed static balance with open eyes (P=0. 06) but these changes were not significant at P≤0. 05. No significant changes were observed in static balance with closed eyes and dynamic balance (P=0. 287، P=0. 133). No significant changes were observed in static balance with open and closed eyes and dynamic balance in control group (P=0. 932، P=0. 237، P=0. 408). The results of this study demonstrated that 8 weeks of resistance training did not have a significant effect on static and dynamic balance in the elderly.

The aim of this study was to assess the relationship between kyphosis and lordosis and balance in students suffering from hyperkyphosis، hyperlordosis، hypokyphosis and hypolordosis and to compare balance between hyperkyphosis and hypokyphosis groups and also between hyperlordosis and hypolordosis groups. For this purpose، 350 students voluntarily participated in this study. Subjects'' scoliosis was screened by spinal mouse device and 20 subjects with hyperkyphosis (mean age 12. 7+0. 80 years، weight 50+1. 01 kg، height 156+0. 09 cm)، 20 subjects with hypokyphosis (mean age 12. 2±0. 89 years، weight 45±1. 11 kg، height 149±0. 11 cm)، 20 subjects with hyperlordosis (mean age 12. 75±0. 96 years، weight 50. 75 ±1. 17 kg، height 151± 0. 11 cm) and 20 subjects with hypolordosis (mean age 12. 1±0. 91 years، weight 48±1. 02 kg، height 153±0. 10 cm) were selected as the sample of this study. The single leg balance test، star excursion balance test and spinal mouse device were used to assess static and dynamic balance and scoliosis. To analyze the data، Pearson correlation and independent t test were used (P≤0. 05). Results showed a negative significant relationship between kyphosis and dynamic and static balance (P≤0. 05). Also، static and dynamic balance was significantly lower in subjects with hyperkyphosis than those with hypokyphosis. No significant difference was observed between lordosis and dynamic and static balance and also between static and dynamic balance in hyperlordosis and hypolordosis groups (P>0. 05). It seems necessary for sports coaches at schools and sport teams to periodically screen the subjects with these deformities especially hyperkyphosis and pay special attention to them as those prone to injury due to their decreased balance in preventive programs.

The aim of this study was to examine the effect of quadriceps fatigue on electromyographic parameters during stance phase of walking. For this purpose، 12 active men (age: 24. 5±2. 27 years، weight: 75. 8±4. 61 kg، height: 178. 6 ± 6. 46 cm) were selected. Leg extension machine was used to induce quadriceps fatigue with 50% of one – repetition maximum load. Surface electromyographic activity of rectus femoris، vastus medialis، vastus lateralis، biceps femoris، semitendinosus، medial gastrocnemius and tibialis anterior muscles were recorded during walking before and after fatigue protocol. Paired t test was used to analyze the data. The results showed a decrease in the activity of selected muscles after fatigue during stance phase of walking. It can be concluded that quadriceps fatigue was accompanied with lower activity of other muscles especially hamstring which can decrease knee joint stability during the stance phase of walking and consequently the probability of knee injury.