Dr , Dr ,
Volume 0, Issue 0 (11-2019)
Abstract
Abstract
Introduction and purpose: Jumping motor tasks in people with motor control defects are probably associated with incomplete movement patterns, which can be related to non-collision injuries of the lower limbs. In relation to these people, it has been recommended that the design of exercise protocols should also be done with the aim of controlling and improving functional defects. Therefore, the aim of the present study is to investigate the eight-week training program of feedback on the biomechanical variables of athletes with selected motor control defects in landing jump tasks.
Materials and methods: The present study is a randomized clinical trial study before and after the intervention. 34 male recreational athletes with movement control defects (dynamic knee valgus and quadriceps dominance) were selected based on the study criteria and then randomly assigned to control groups with a ratio of 1:1 (age range, 28.10±4.70years; height, 171±5.49cm; mass, 76.83±5.81kg; and BMI, 22.12± 1.54kg/m² ) and feedback group (age range, 29.80±3.61years; height, 173.80 ± 4.70cm; mass, 78.33±4.64kg; and BMI, 21.40±1.77 kg/m² ).Electromyography data (vastus medialis, vastus lateralis, gluteus medius, Tensor fasciae latae and biceps femoris) and lower limb kinematics (knee valgus angle) were recorded while the participants performed the landing jump movement tasks (vertical jump, tuck and countermovement) in the two previous stages. From the protocol and after the protocol, they performed jumping exercises for two months. In addition, external feedback (first by using educational videos and then verbally while doing the task (place the knee in line with the toes, press the knee towards the wall (external source)) during the two months of the training program and during Performance of movement tasks was presented to the feedback group. To analyze the data, two-way analysis of variance and Bonferroni statistical tests were used for each movement task at a significance level of P < 0.05.
Findings: The results of the study indicated an increase in the electrical activity of the VM and GM muscles and a decrease in the electrical activity of theVL, BF and TF muscles in different phases of jumping in the feedback group. As an example, the results of the Bonferroni post hoc test showed a significant improvement in the feedback group in the amount of electrical activity of the VM muscle (effect size = 0.57, p = 0.001) and GM(effect size = 0.53, p = 0.002). In the eccentric phase, there was a significant improvement in the amount of electrical activity of the VM muscle (effect size = 1.05, p = 0.001) and GM(effect size = 0.77, p = 0.001) in the maximum knee flexion phase and improvement The electrical activity of VM muscle (effect size = 1.71, p = 0.001) and GM (effect size = 1.19, p = 0.001) had significance in the landing moment phase during vine jump. Also, the feedback group showed a decrease in knee valgus angle in the frontal plane (P < 0.05).
Conclusion: The results of the present study showed that feedback has an effect on kinematic and electromyographic parameters and improves the jump-landing biomechanics of the lower limbs in people with knee motor control defects and can be used to correct incomplete movement patterns in jump-landing tasks. be used However, for a general conclusion, more studies are needed in different groups and different sports levels, as well as more samples.
N Jamali, Kh Khayambashi, Sh Lenjannejadian, H Esmaeili,
Volume 18, Issue 19 (7-2020)
Abstract
Although hip muscle strengthening has been reported as an effective way to decrease PFPS symptoms, however its effect on lower extremity kinematics is less clear. The current study was done with the aim of investigating the effect of hip abductor and external rotator muscles strengthening exercises on lower extremity kinematics in static and dynamic states. In a randomized controlled trial, 33 patients with patellofemoral pain (PFP) were randomly assigned into exercise (8 female, 30±6.8 y/o, 23.8±2.6 BMI and 8 male, 31.2±7 y/o, 25.6±1.5 BMI) and control (9 female, 29.9±7.3 y/o, 23.2±3.2 BMI and 8 male, 32±6 y/o, 25.5±1.9 BMI) groups. In exercise group they received hip abductor and external rotator strengthening exercises by thera-band 3 times per week for 12 weeks under supervision by a physiotherapist. The control group did not receive any training intervention. Hip muscles strength and kinematics in static and dynamic states, were assessed at baseline and post-intervention. Repeated measures ANOVA by using SPSS were applied to assess the effects of the exercise on measured variables (α=0/05). After 12 weeks of strengthening program, by an increase in abductor muscle strength in women from 19.6 to 26.4 %BW (P=0.000) and in men from 29.9 to 38.1 %BW (P=0.003), and in hip external rotator muscles in women from 13.2 to 16.9 %BW (P=0.024) and in men from 26.3 to 34.9 %BW (P=0.000), dynamic knee valgus angle during single-legged squat improved in women from 170 to 174.6 degrees (P=0.018) and in men from 171.8 to 176.8 degrees (P=0.017) and contralateral pelvic drop angle during stair descending improved only in women from 7.9 to 6 degrees (P=0.04) in the exercise group. No significant difference was observed at quadriceps angle (P≥0.05). The findings suggest that hip muscles strengthening can alter the lower extremity kinematics, in dynamic state, at the frontal plane, and it might be said that due to these changes following hip abductor and external rotator muscles strengthening exercises by thera-band, the symptoms of PFP improve more consistent.
