ABSTRACT
The reliability of surface electromyographic [sEMG] variables during swallowing determines the potential usefulness of these measures in swallowing assessment and treatment. This study aimed to establish the reliability of the sEMG measures of the swallowing function of muscles during different swallowing conditions in healthy young and old volunteers. Two groups of volunteers [24 older adults, 10 younger adults] participated in this cross-sectional study during 2014. The activity of masseter, submental, and infrahyoid groups were measured using sEMG during three repetitions of different swallowing tasks. Both the relative and absolute reliability [characterized respectively by ICC, SEM%, and SRD%] were calculated for the sEMG indices of muscle activity during swallowing events. Statistical analyses were performed by the SPSS 19.0 and Microsoft Excel 2007 software packages. Statistical significance was set at P
ABSTRACT
Purpose: In approaching full trunk flexion [75%-80% of full flexion], myoelectric activity of lumbar erector spinae muscles is reduced or silenced; this response is known as flexion-relaxation phenomenon [FRP]. FRP is a shift in load sharing and spinal stabilization from active structures [erector spinae muscles] to passive ligamentous and articular structures. Static lumbar flexion under constant displacement or load, within the physiological range, elicits creep in lumbar viscoelastic tissues. During a short static lumbar flexion, significant changes are elicited in the muscular activity pattern of the FRP. Laxity in the passive tissues of the spine during prolonged spinal flexion disturbs the spinal stability. This study investigated the effects of Kinesio taping [KT] before and after periods of the static lumbar flexion on the timing of FRP for the erector spinae muscles
Methods: The research was conducted on 22 healthy female college students. The surface electromyographic silence and onset of the erector spinae muscle activities were measured in two states; before the static lumbar flexion and 10 minutes after the static lumbar flexion in two conditions [with and without KT]
Results: The results indicate that KT causes erector spinae muscles relaxation earlier in the flexion and later reactivated in the extension. In other words, KT increased flexion relaxation time in erector spinae muscles [P<0.05]. The results also indicate that 10 minutes static lumbar flexion will produce relaxation of the erector spinae muscles later during the forward bending activity and earlier reactivation during the extension [P<0.05]. Application of KT cannot compensate the effects of 10 minutes static flexion at the onset and the silence of flexion relaxation and over again creep causes FRP occurs later
Conclusion: According to the effects of KT before the creep in reducing the duration of the muscles activity, kinesio tape may be used in reducing muscle spasms and duration of erector spinae muscles activity. It may also improve FRP in the back and the people who are predisposed to the back pain and FRP has not seen in them. Therefore, the need for research on these subjects and other factors, such as the electrical activity of muscles is essential. Although the application of KT cannot substitute the effects of 10 minutes static flexion on the onset and the silence of flexion relaxation, it could be used for protection and reduction of using strained viscoelastic structures
ABSTRACT
Purpose: The purpose of this study was to investigate the kinematic and kinetic variables, which predict anterior tibia shear force during single-leg landing in female athletes
Methods: Forty-three subjects [mean and standard deviation for age 21.12 +/- 2.00 y, height 168.58 +/- 7.62 cm, and weight 60.27 +/- 7.80 kg] participated in this study. Kinematic and kinetic variables of lower extremity and trunk during single-leg landing were collected by 5 Vicon cameras and Kistler force plate. Stepwise multiple regression and Pearson correlation were used to identify predictor variables of anterior shear force [P
Results: Peak of extensor moment [P = 0.004, r = -0.394] and maximum knee flexion [P = 0.007, r = -0.370] were the best predictors that explained 30% of the variance of the shear force data. Therefore, rise in maximum extensors moment of knee and knee maximum flexion causes increase and decrease in anterior shear force, respectively. In addition, a significant relationship between trunk flexion [P = 0.039] and knee flexion angular velocity [P = 0.048] at the moment of initial contact with the anterior shear force
Conclusion: On the basis of previous research, and the relationship between clinical findings, the noncontact of anterior cruciate ligament injury during landing was confirmed. These results can be used in prospective studies examining modifiable noncontact risk factors of ACL injury
ABSTRACT
Purpose: Mechanical loading is said to be an important factor in the development of low back pain [LBP]. One of the main concerns in manual material handling [MMH] tasks is lifting loads, as this activity is present in most jobs. Despite the controversy about their effectiveness, belts are used in industry as either protective or assistive devices in manual load handling. The present investigation aimed to determine whether a commonly used back belt could improve maximum center of pressure displacement [COPMD] and center of pressure velocity [COPV] as the balance parameters during each of three common styles of lifting [squat, semi-squat, stoop]
Methods: Twenty healthy female subjects participated in this study who were selected by non-probability convenience sampling. The participants stood barefoot on the force plate. They lifted a box, weighting 4.53 kg [10 pound]. The subjects were instructed to bend their knees [squat] or their lumbar [stoop] or both their knees and lumbar [semi-squat], to grasp the box handles, and to lift the load to the level of greater trochanter height. Half of the subjects performed the 3 trials with wearing belt at first try and the other half performed the trials without wearing the belt at first try
Results: The mean of maximum displacement and velocity showed that there was a trend of increase in these variables in all 3 styles of lifting [squat, semi-squat and stoop] after wearing belt. One-way ANOVA with repeated measures results for COPMD and COPV showed that 'Belt condition' significantly affected the dependent variables
Conclusion: Wearing belt may decrease stability caused by increased COPMD and COPV
ABSTRACT
A number of studies have investigated the effect of age, trauma, disease and fatigue on cervical joint position sense. However, there is an absence in data regarding the role of posture on proprioception. The aim of the current study was to investigate the effect of Forward Head Posture [FHP] on cervical joint position sense. Twenty Forward Head Posture volunteers [14 women, 6 men], with the mean age of 23.94 [SD=3.26] years, and 17 normal head posture volunteers [8 women, 9 men] with the mean age of 23.50 [SD=2.68] years were asked to perform the Cervicocephalic relocation test [CRT] to the neutral head position [NHP]. The aim of this test was to evaluate the participants' ability to relocate the head to neutral position after they actively rotated it to left and right sides. Three trials were performed for each rotation to the left and right. In order to assess cervical joint repositioning accuracy, Absolute, Constant and Variable errors were used. No significant difference in repositioning errors was observed between experimental and control group in absolute and constant errors [P>0.05]; however, compared to normal group, Forward Head Posture subjects manifested significantly higher levels of variable errors [P<0.05]. Forward Head Posture can significantly affect the positioning consistency of cervical proprioception. Nonetheless, further investigation on the effect of Forward Head Posture on cervical proprioception in altered situations is recommended
ABSTRACT
Delayed onset muscle soreness [DOMS], which occurs after eccentric exercises, may cause some reduction in ability in sport activities. For this reason, numerous recovery strategies have been used in an attempt to control the inflammatory-type response. Physical modalities have demonstrated no effect on the alleviation of muscle soreness or other DOMS symptoms. Whole-body vibration [WBV] has been suggested as a viable warm-up in sport fields. However, there is a lack of scientific evidence to support the protective effects of WBV-Training [WBVT] on muscle damage. Thirty-two healthy untrained volunteers randomly assigned into two groups: WBVT [n=15] and control [n=17]. Subjects performed 6 sets of 10 maximal isokinetic [60[degree sign].s-1] eccentric contractions of knee extensors with dominant limb on a dynamometer. In the WBVT group before eccentric exercise, whole body vibration was applied using a vibratory platform [Power Plate, 35 Hz, 5 mm peak-to-peak amplitude], with 100 [degree sign] knee flexion for 60 seconds while no vibration was applied in the control group. DOMS criteria [serum creatine kinase [CK], pressure pain threshold [PPT], muscle soreness, thigh circumference and maximal voluntary isometric exertion] were recorded at baseline, immediately after, 1to 14 days postexercise. WBVT group showed significant reduction of DOMS symptoms in terms of lower CK levels, less PPT, less muscle soreness and lower maximal isometric voluntary strength loss compared to the control group [P< 0.05] However, no significant effect on thigh circumference was evident [P> 0.05]. The findings of this study showed that WBVT administered before eccentric exercise may control and prevent DOMS and enhance the quadriceps muscle activity. Further investigation should be undertaken to ascertain the effectiveness of WBVT in athletes
ABSTRACT
Shoulder muscle timing is very important, however, study on the shoulder muscle timing and recruitment patterns is limited. Thus, the aim of the study was to determine and compare the timing and recruitment order of the shoulder muscles in subjects with and without Shoulder Impingement Syndrome [SIS]. In this case-control study, 9 female subjects with shoulder impingement syndrome and 13 matched healthy female volunteer subjects selected by simple-non random sampling participated. Surface electromyography of serratus anterior, pectoralis major, upper trapezium, lower trapezium, posterior deltoid, and anterior deltoid muscles of dominant side were recorded during D1flex movement. Muscle latency time, relative muscle latency time and recruitment order were processed and compared in subjects with and without SIS. Non parametric test [2 independent samples [Mann-Whitney U]] was used for data analysis In patient group some muscles showed a greater latency time than healthy group but this increase wasn't statistically significant. Also, in patient group recruitment order of shoulder muscles was changed. Altered recruitment patterns of one or more muscles in the patient group as compared to healthy group indicate neuromuscular control has changed. Thus rehabilitation programs should be designed to restore and optimize the activation sequences and motor control of these muscles
ABSTRACT
Conventional balance test such as electronystagmography and videonystagmography, which are vision-dependant, are not practical in blind patients. Instead, vestibular evoked myogenic potential, not needing any vision, seems to be a more appropriate test for evaluating the vestibular system, in these patients. This study aimed to assess the prevalence and the latencies of p13 and n23 waves among congenitally blind and sighted participants evaluated by vestibular evoked myogenic potential. In a cross-sectional study, vestibular evoked myogenic potential was recorded for 20 slighted and 20 congenitally blind subjects, aged 18 to 30 years old, using 500 Hz-tone bursts [95 dBnHL]. Vestibular evoked myogenic potentials responses were present in all [100%] of the participants. Considering the results of the both ears, there was no significant difference between mean p13 and n23 latencies of the two groups [p>0.05]. Formation of vestibular evoked myogenic potentials reflex arc and neural pathway in congenitally blind patients is similar to slighted individuals; hence, the development of this pathway is independent of the visual system. Vestibular evoked myogenic potentials test is a useful test to assess vestibular function of the blinds
ABSTRACT
The use of back support is one of the common methods aimed to prevent low back pain. The purpose of the present study was to investigate the effect of wearing a lumbosacral support on lumbar spine velocity and torque in six directions during combined trunk motion. In this interventional study, 30 young healthy men were selected simply from convenient samples. They were asked to stand in Isostation B200 system and perform three-dimensional trunk motion against a resistance of 50% of maximal voluntary contraction torque while wearing or not wearing a lumbosacral support. Under each condition of test, five successive motions of trunk were performed in downward direction [as flexion, right lateral flexion, and right rotation] and upward direction [as extension, left lateral flexion, and left rotation], and the variables of average velocity and average torque were recorded during motion. With the use of a lumbosacral support, average velocity was significantly increased in flexion [P=0.015] and extension [P=0.005], but no significant changes were found in other directions [P>0/05]. Back support decreased average torque of right rotation significantly [P=0.006], but did not significantly changed this variable in other directions [P>0/05]. Wearing a lumbosacral support can increase velocity in sagittal plane. Decreased rotation torque of trunk, as a result of using a back support, may reduce the twisting forces on lumbar spine joints