motor control

Aims :

Pain and altered motor control are consequences of chronic low back pain (LBP). The present study aimed to assess the effects of a six-week Swiss ball core stabilization program on pain levels and lumbopelvic motor control in patients suffering from nonspecific LBP.

Materials & Methods :

This randomized clinical pilot study involved 24 participants (12 females and 12 males) who were diagnosed with nonspecific chronic LBP (mean age=42.08±7.05 years). Participants were randomly assigned to two groups: experimental (n=12) and control (n=12). The experimental group underwent a six-week intervention of core stability exercises, while the control group received routine physical therapy. The primary outcome measured was pain intensity using a visual analog scale ranging from 0-10. Secondary outcomes included lumbopelvic motor control, which was assessed using various tests, such as the knee lift abdominal test, bent knee fall-out test, Waiter's Bow test, sitting knee extension test, and transversus abdominis test. Evaluations were conducted at three time points: baseline, the end of a six-week intervention, and after one month of follow-up.

Findings :

The core intervention resulted in a significant increase in motor control during the post-test (P<.001; Cohen's d=6.04), although this effect did not persist in the follow-up assessment. Moreover, a significant decrease in pain intensity was observed both during the post-test (P<.001; Cohen's d=3.31) and follow-up (P<.001; Cohen's d=2.98) periods. Furthermore, significant differences were identified between the two groups in all outcome measures following the intervention (P<.05).

Compared to routine physical therapy, the six-week core stability exercises on the Swiss ball resulted in marked improvements in pain intensity and lumbopelvic motor control in patients with nonspecific chronic LBP.

 Surface electromyography (sEMG) represents a widely utilized technique in medical research. The voluntary response index (VRI) introduces a novel method for analyzing the motor control of voluntary movements via sEMG. This study aimed to assess the reliability of VRI and breakpoint angles (BPA) among professional football players during the Nordic Hamstring test (NHT).

 This study included 24 healthy professional football players. Through the use of sEMG, two aspects of VRI [magnitude (MAG) and similarity index (SI)] were evaluated during the NHT. Additionally, BPAs were determined by capturing slow-motion videos of functional tasks. The test-retest reliability across three trials was determined using the intra-class correlation coefficient (ICC).

 The reliability of the VRI components during the NHT was found to be excellent. The ICC for MAG was 0.9 and 0.81 for the SI. Breakpoint angles exhibited moderate reliability (ICC = 0.65) during a functional task. The SI displayed a lower standard error of measurement (SEM = 0.07). The MAG’s SEM was 0.25, while BPA’s SEM was 17.8.

 The analysis of the VRI via sEMG showed nearly perfect reliability in professional football players during the NHT, a functional task. Breakpoint angles demonstrated significant reliability. The findings of this study indicate that both VRI and BPA are reliable methods for estimating motor control during dynamic movement tasks in professional athletes.

Dynamic balance monitoring involves the assessment of the muscular control during changes of the centre of gravity location in space above the supporting plane. We aimed to determine the structure of the Y-Balance Test and its accuracy based on measurements of strength and resistance to fatigue of muscles acting on the knee joint under static conditions, as well as joint motion ranges and static balance in girls aged 14 years.

The study included 40 girls aged 14, who attended Gymnasium No. 2 in Cracow (Poland). The re-search was conducted in October 2020. Postural stability was examined with the use of the YBT. The measure-ments of muscle strength and knee joint extensor and flexor resistance to fatigue during an isometric contrac-tion were performed in a standard position on the test bench. The measurements of lower extremity joint range of motion were performed in accordance with the SFTR methodology. Static balance was assessed with the use of the modified FBT.

The factor structure obtained for both lower extremities has satisfactorily explained the common vari-ance (about 70%) and showed slight differences between the left and right extremities.

The factor structure in the group of examined girls suggests a highly hybrid nature of the Y-Balance Test with a wide spectrum of biomechanical variables that have little influence on the measurement results.

Unusual gaze behavior in children with autism spectrum disorder (ASD) was reported very early in the literature.

The current study examined gaze behavior in children with ASD and typically developing (TD) children while performing an active balance task on the Wii balance board.

8 children (male) diagnosed with high-functioning ASD and 9 TD children (3 female, 6 male) were recruited for the study. Eye movements were recorded at 60 Hz during the soccer game on Wii balance board.

There was no significant difference in the game scores between the two groups (p > 0.05). However, evidence indicates differences in gaze behavior, particularly total fixation durations on the main area of interest (center AOI) (p < 0.05). While performing the active balance task, children with ASD spent less time looking at the center of the screen than typically developing children. Shorter fixation durations in ASD compared to the TD group could indicate how our ASD group had enhanced perceptual processing. The second possibility for shorter total fixation duration in ASD is that they are more scattered in their fixations.

Shorter fixation durations in children with ASD while performing the active balance task could be because of enhanced perceptual processing or a deficiency in their ability to plan. However, no advantage or disadvantage was observed in the Wii-fit game’s performance.

One of the most complex problems of elders is the balance problem and the increased risk of falling. Body percussion is an effective treatment for various diseases with cognitive, physical, and psychological deficits and improves the memory, motor, and coordination skills, as well as the social interaction of patients with neurological diseases. One of the problems in the elderly is the weakness in balance skills and falling. This study aimed to investigate the effect of body percussion exercises (BPE) on the balance of the elderly.

This study was carried out as pretest-posttest research with two experimental and control groups. A 12-session therapeutic program was implemented 3 days a week each for 45-60 minutes. The subjects were evaluated using the Berg balance scale, functional reach, and timed up and go (TUG) tests. Data were analyzed by paired and independent t tests.

The results of the treatment group showed a significant effect of BPE on the balance (P<0.005). A comparison of post-treatment results showed that the Berg balance scale (P=0.00), and timed up and go (P=0.023) were significantly different. The functional reach test (P=0.174) was not significantly different.

This study showed that BPE had a significant effect on the elderly`s balance.

Nonlinear dynamics, especially the chaos characteristics, are useful in analyzing bio‑potentials with many complexities. In this study, the evaluation of arm‑tip force estimation method from the electroencephalography (EEG) signal in the vertical plane has been studied and chaos characteristics, including fractal dimension, Lyapunov exponent, entropy, and correlation dimension characteristics of EEG signals have been measured and analyzed at different levels of forces.

Electromyography signal was recorded with the help of the BIOPEC device (the Mp‑100 model) and from the forearm muscle with surface electrodes, and the EEG signals were recorded from five major motor‑related cortical areas according to 10–20 standard three times in a normal healthy 33‑year‑old male, athlete and right handed simultaneously with importing a force to 10 sinkers weighing from 10 to 100 Newton with step 10 Newton.

The findings confirm that force estimation through EEG signals is feasible, especially using fractal dimension feature. The R‑squared values for Fractal dimension, Lyapunov exponent, and entropy and correlation dimension features for linear trend line were 0.93, 0.7, 0.86, and 0.41, respectively.

The linear increase of characteristics especially fractal dimension and entropy, together with the results from other EEG and neuroimaging studies, suggests that under normal conditions, brain recruits motor neurons at a linear progress when increasing the force.

There is conflicting evidence in favor of the hemispheric distribution of motor planning. Some studies supported the left-hemisphere-dominance hypothesis for motor planning and claimed that the left-hemisphere has a crucial function in motor control even in left-handers. The present study aimed to compare the right- and left-handed participants on motor planning ability and to investigate the performance of their dominant hands in a specific action selection task. Also, the effect of task complexity was assessed.

Twenty right-handers and 20 left-handers performed an action selection task. The participants had to grasp a hexagonal knob with their dominant hand and consequently rotated it 60° or 180 ° clockwise or counterclockwise. Depending on our objects, we used mixed factorial ANOVA and the groups were examined in terms of the planning time, grasping time, releasing time and planning pattern for initial grip selection. The SPSS 19 was used for analyzing the data and p≤0.05 was considered as the significant level.

No significant differences were observed between the two groups. The movement-related measures revealed a main effect of rotation (p˂0.001). However, a significant interaction between direction × planning pattern × group (p˂0.001) indicated a preferential bias for rotatory movements in the medial direction which is consistent with the “medial over lateral advantage”.

Both left- and right-handed participants had a similar motor planning ability while performing a planning task with their dominant hands. Because our study was behavioral, it only provided a test of the left-hemisphere hypothesis of motor planning.

In recent years, galvanic vestibular stimulation (GVS) has been used as an effective method in rehabilitation and treatment of psychological disorders in children and adults. This study was designed to evaluate the effect of GVS on response inhibition and susta ined attention in children with attention-deficit/hyperactivity disorder (ADHD).

Seventeen children with ADHD, within the age range of 9−12 years, participated in this study. All participants were exposed to the go/no-go task. The behavioral outcomes and event-related potentials were recorded at baseline status, in sham condition, and after 20 minutes of exposure to GVS polarities, with an anode on the right mastoid region and a cathode on the left mastoid region.

The results showed that there was a significant difference in reducing the behavioral response of the commission error (p < 0.05). But the reduction in behavioral responses to omission error and reaction time were not significant (p > 0.05). However, regarding ERPs, reduced latencies and increased amplitudes of N2 and P3 waves were observed in GVS intervention, compared to the baseline and sham conditions (p < 0.05).

The present results indicated the potential of GVS in improving of cognition function in children with ADHD and could help us develop a new strategy for rehabilitation of response inhibition disorders in the future.

The main aim of this study was to determine and compare the effects of innovative aquatic proprioceptive training plus conventional rehabilitation with conventional rehabilitation alone on voluntary response index (VRI) components in athletes with anterior cruciate ligament reconstruction (ACLR).

Forty male athletes with ACLR (18 - 35 years of age) voluntarily participated in this study. They were randomly allocated into two groups. The conventional therapy group (n = 20) underwent conventional rehabilitation for ten weeks, three sessions a week. The aquatic proprioceptive training plus conventional rehabilitation (n = 20) group received the same conventional rehabilitation plus 30 sessions of innovative hydrotherapy exercises. Voluntary response index analysis was carried out to determine changes in motor control and muscle activation patterns based on electromyographic (EMG) outcome measures.

There was a significant difference in the magnitude (MAG) and similarity index (SI) between the two groups at all phases of the functional task (sit-stand-sit) (P < 0.05). Also, both groups showed a significant change in MAG and SI at all phases of the functional task (sit-stand-sit) after the intervention (P < 0.05). Effect size in both groups for MAG and SI at all phases of the functional task (sit-stand-sit) ranged from 2.5 to 4.61 and from 0.29 to 1.7, respectively.

The incorporation of innovative aquatic proprioceptive training into conventional accelerated rehabilitation protocol leads to changes in motor control due to changes in the muscle activation pattern after the intervention.

To identify the effect of imagery exercises on activity of the shoulder muscles.

A sample of 23 healthy participants (17 females and 6 males), with no history of shoulder injury, participated in the present study. Surface bipolar electrodes were applied over the supraspinatus, infraspinatus, posterior deltoid, middle deltoid, anterior deltoid, and pectoralis major. Participants performed six imagery exercises: flexion, extension, abduction, adduction, external rotation, and internal rotation. Root mean square of myoelectric activity of shoulder muscles was calculated for statistical analysis. The RMS during rest was used as an offset and also to normalize the activity of each muscle during imagery exercises.

Performing the imagery exercises resulted in significant activation of the shoulder muscles (P < 0.01). In the case of the supraspinatus muscle, significant difference (P< 0.05) was found among exercise types but no significant value was seen for infraspinatus muscle. In flexion, abduction, adduction, and internal rotation imagery exercises, the correlation observed between muscles activation was significant (P<0.01).

Supraspinatus highly activated in exercises including elevation of the arm. Activation of infraspinatus in all exercises suggest its important stability role in glenohumeral joint.

Voluntary Response Index (VRI) is used as a measure of motor control to study abnormalities of voluntary movements. This study aimed to evaluate the reliability of voluntary response index analysis in subjects with Anterior Cruciate Ligament Reconstruction (ACLR).

Using surface electromyography, the VRI components of both groups of 15 ACLR and 15 healthy controls were assessed during the functional task (sit-stand-sit). The outcome variables of VRI included the magnitude and similarity index.

In sit to stand phase, high reliability was found (ICC=0.80-0.89) for the magnitude and similarity index in both groups. In the standing phase, high to very high reliability was found for the magnitude and similarity index in both groups (ICC=0.75-0.91). In stand to sit phase, high to very high reliability was found (ICC=0.78-0.92) for the magnitude and similarity index in both groups.

Surface electromyographic measurements of VRI analysis demonstrated high to very high reliability in athletes with ACLR during the functional task (sit-stand-sit). The results of the current study showed that the VRI analysis in athletes after ACLR was a reliable method and can be used to evaluate motor control before and after ligament injury in these patients.

Onset and offset activation of lower limb and trunk muscles may change the knee with genu varum during landing. These motor control strategies can be different from those in healthy subjects and contribute to more injuries in lower extremities. This study aimed to compare the delay time of the onset activity of the abdominal and lower limb muscles in the specific landing task.

Ten females with genu varum deformity and ten females with normal knee participated in this case-control study. Genu varum deformity was measured by a camera capturing goniometer. The subjects were informed to land by preferred lower limb from a table (30 cm high) on a force plate. Vertical Ground Reaction Force (VGRF) was measured to clarify the onset of the landing task. Surface Electromyography (sEMG) of transverse abdominal/int. oblique (TA/IO), Vastus Medialis (VM), Vastus Lateralis (VL), Lateral Gastrocnemius (LG), and medial gastrocnemius (MG) muscles were recorded during landing. The difference between the onset activity of the above muscles and onset of VGRF was calculated as delay times and compared between muscles and between two groups. Also, the offset of activities and the intensity of muscle activation (normalized RMS) were compared between the two groups.

Lower limb and trunk muscles showed significantly different onset of activities in the genu varum group (P<0.05), whereas there was no significant difference in the onset of muscle activities in the healthy group. Results indicated significant differences between two groups in TA/IO, LG, and MG muscles and the genu varum group had longer delay time for motor control strategy (especially ankle strategy) in the landing task. Offset time of all muscles in the genu varum and healthy subjects had a significant difference between muscles, especially in gastrocnemius muscles (P<0.05). Also, there were significant changes between the two groups in LG and MG muscles (P<0.05). Normalized muscle activities (nRMS) generally indicated an increase in muscle activation of genu varum subjects (TA/IO, LG, MG) compared with the normal subjects (P<0.05).

Motor control strategies in landing task is different in the genu varum group due to changes in biomechanics and properties of the knee joint. This variation may be due to changes in proprioception afferent pathways around the knee joint. An increase in muscle activation, delay, and offset time of muscle activities in these subjects, indicated that an increase in the degree of freedom may change motor control strategies. Internal anticipation and postural adjustment of the landing task in these subjects need more motor unit recruitment (an increase in nRMS). This deformity in the knee joint might affect some activities and possibly cause knee changes such as osteoarthritis.

Patients with non-specific low back pain (NSLBP) and movement control dysfunction demonstrate alternation in hip muscles flexibility and spinal movement patterns. Therapeutic modalities that augment hip muscles flexibility could help these patients. The aim of this study was to investigate the effect of global postural reeducation (GPR) on pain and hip muscle flexibility in patients with NSLBP and movement control dysfunction.

A total of 27 men with a mean age of 31.21 ± 2.5147 years, height of 166.44 ± 6.11 cm, and weight of 64.21 ± 5.25 kg participated in this study. The visual analogue scale (VAS) was used to evaluate pain. The flexibility of hip muscles (rectus femoris, tensor fasciae latae, external rotators and hamstring) was measured using universal goniometer. All data were assessed at baseline and after the intervention. The Shapiro-Wilk test and paired t test were used for statistical analysis at significance level of P = 0.05.

Our results revealed a decline in pain (P < 0.004) and an increase in the flexibility of the hamstring muscles in the right (P < 0.003) and left (P < 0.003) legs. There were no statistically significant differences in the flexibility of rectus femoris muscle, external rotators, and tensor fasciae latae.

The results suggest that GPR had a significant effect on the level of pain. Further, it affected the flexibility of hamstring muscles in legs. Using GPR is recommended for pain relief and improving the flexibility of hamstring muscles in patients with NSLBP.