Bilateral Muscle Strength Research Articles

Application of cross-migration theory in limb rehabilitation of stroke patients with hemiplegia.

Stroke is a common cause of neurological dysfunction, often resulting in hemiplegia. Thus, rehabilitation of limb function in stroke patients is an important step towards accelerating recovery and improving quality of life. To investigate whether unilateral strength training in hemiplegic stroke patients could lead to cross-migration, an increase in bilateral muscle strength, and an improvement in lower limb motor function. We randomly divided 120 patients with hemiplegic stroke into two groups: Eexperimental and control groups, with 60 patients in each group. Both groups received routine rehabilitation treatment, while the experimental group additionally received ankle dorsiflexion resistance training on the healthy side for 6 wk. We measured the maximum voluntary contract (MVC), changes in surface electromyography (EMG), and the lower limb motor function using the simplified Fugl Meyer Motor Function Assessment Scale (FMA) before and within 1 wk after training. The FMA score in the experimental group improved significantly compared to both their pre-training score and the control group's post-training score (P < 0.05). The integrated EMG of the anterior tibialis muscle and pulmonary intestine muscle in the experimental group were significantly different after training than before (P < 0.05). Furthermore, the MVC of the anterior tibialis muscle on both the healthy and affected sides and the MVC of the pulmonary intestine muscle on both sides showed significant improvement compared with before training and the control group (P < 0.05). Our findings suggest that ankle dorsiflexion resistance training on the healthy side in hemiplegic stroke patients can increase strength in the opposite tibialis anterior muscle and antagonist's muscle, indicating a cross-migration phenomenon of strength training. Furthermore, this type of training can also improve lower limb motor function, providing a new exercise method for improving early ankle dorsiflexion dysfunction.

Aicardi-Goutières syndrome type 7 in a Chinese child: A case report

IFIH1 is a protein-coding gene. Disorders associated with IFIH1 include Aicardi-Goutières syndrome (AGS) type 7 and Singleton-Merten syndrome type 1. Related pathways include RIG-I/MDA5-mediated induction of the interferon (IFN)-α/β pathway and the innate immune system. AGS type 7 is an autosomal dominant inflammatory disorder characterized by severe neurological impairment. In infancy, most patients present with psychomotor retardation, axial hypotonia, spasticity, and brain imaging changes Laboratory assessments showed increased IFN-α activity with upregulation of IFN signaling and IFN-stimulated gene expression. Some patients develop normally in the early stage, and then have episodic neurological deficits. The 5-year-old girl presented with postpartum height and weight growth retardation, language retardation, brain atrophy, convulsions, and growth hormone deficiency. DNA samples were obtained from peripheral blood from the child and her parents for whole-exome sequencing and test of genome-wide copy number variation. Heterozygous mutations in the IFIH1 gene were found. Physical examination at admission found that language development was delayed, the reaction to name calling was average, there was no communication with people, but there was eye contact, no social smile, and no autonomous language. However, the child had rich gesture language and body language, could understand instructions, had bad temper. When she wants to achieve something, she starts crying or shouting. Cardiopulmonary examination showed no obvious abnormality, and abdominal examination was normal. Bilateral muscle strength and muscle tone were symmetrical and slightly decreased. Physiological reflexes exist, but pathological reflexes were not elicited. We reported the clinical characteristics of a Chinese child with a clinical diagnosis of AGS type 7, which expanded the mutational spectrum of the IFIH1 gene.

중학교 축구선수의 BMI 수준에 따른 기능 체력과 등속성 근기능의 비교

The purpose of this investigation was to compare functional fitness and isokinetic muscle function according to BMI (body mass index) in middle school soccer player. For this purpose, 34 male middle school soccer players[underweight group(n=12), BMI18.5 kg/㎡; normal weight group(n=15), BMI 18.5~23.0 kg/㎡; overweight group(n=7), BMI 23.0~25.0 kg/㎡] participated in this study. Measurement items were BMI, functional fitness (sargent jump, trunk flexion, eyes one leg standing, semo agility test), and isokinetic muscle function (peak torque, peak torque per body weight, hamstrings/quadriceps ratio, bilateral ratio). The results of our study are as follows: 1) The low BMI group showed excellent flexibility and agility than the high BMI group. 2) In the isokinetic muscle function according to the BMI level, peak torque was higher in the normal weight group than in the underweight group, and peak torque per body weight was lower in the overweight group than in the normal and underweight group. 3) The ipsilateral and bilateral muscle strength ratios were within the normal range for all groups. Therefore, in the case of male middle school soccer players, it was found that overweight had a more negative effect on functional fitness and isokinetic muscle function. Soccer players should try to maintain a normal weight for the best performance.

Performance-based physical function correlates with walking speed and distance at 3 months post unilateral total knee arthroplasty.

After total knee arthroplasty (TKA), walking speed and distance are main concerns of patients. Which physical functions affect walking speed and distance after TKA? Cross-sectional data from 149 patients who underwent unilateral primary TKA and completed performance-based physical function tests. Instrumental gait evaluation for spatiotemporal parameters, isometric knee extensor and flexor strength of both knees, 6-minute walk test (6MWT), timed up-and-go (TUG) test, timed stair climbing test (SCT), and knee flexion and extension range of motion (ROM) of surgical knee were examined. Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) and EuroQol five dimensions (EQ-5D) questionnaires were also performed. Univariate analyses revealed that post-operative walking speed showed significant positive correlations with cadence, stride length, propulsion index of surgical and non-surgical knee, peak torque (PT) of the extensor of surgical and non-surgical knee and flexor of surgical and non-surgical knee, 6MWT, EQ-5D, and significant negative correlations with gait cycle duration, TUG, SCT-ascent and descent, and WOMAC-pain scores. Post-operative walking distance had significant positive correlations with walking speed, cadence, stride length, swing phase duration, propulsion index of surgical and non-surgical knee, PT of the extensor of surgical and non-surgical knee, EQ-5D, and significant negative correlation with gait cycle duration, double support duration, TUG, SCT-ascent and descent. In the multivariate linear regression analyses, TUG, cadence, stride length and propulsion index of non-surgical knee were factor correlated with post-operative walking speed. The SCT-ascent and descent, TUG and propulsion index of surgical knee were factor correlated with post-operative walking distance. Physical performance factors correlated with walking speed and distance at 3 months after surgery. Based on these observations, rehabilitation of bilateral muscle strength and functional mobility would be important for functional recovery after unilateral TKA.

BMI 수준별 노인여성의 무릎관절 등속성 근력의 비교

The purpose of this study was to investigate the characteristic analysis of knee joint isokinetic muscular strength according to BMI (body mass index) in elderly women. The eighty-six elderly women over 65 ages involved voluntary in this study. They were separated normal (18.5~22.9 ㎏/㎡, n=14), overweight (23~24.9 ㎏/㎡, n=16), class 1 obesity (25~29.9 ㎏/㎡, n=34), class 2 obesity group (30~34.9 ㎏/㎡, n=22) by BMI. The data was analyzed by using descriptive statistics, one-way ANOVA, and Scheffe post-hoc. The results of our study are as follows : 1) Peak torque at 60°/sec was the highest in the overweight group and the lowest in the class 2 obesity group. Peak torque % body weight showed similar trends in the normal and overweight groups, followed by the class 1 obesity group and the class 2 obesity group. 2) Peak torque at 180°/sec was higher in the class 1 obesity group than the class 2 obesity group in the left extensor and right flexors. Peak torque % body weight was found to be higher in the normal weight group, the overweight group, and the class 1 obesity group than in the class 2 obesity group in all variables. 3) The hamstrings/quadriceps ratio showed significant differences between groups in all variables, and the bilateral muscle strength ratio did not show any significant difference between groups. In conclusion, It was found that if the WHO obesity standard of 30 ㎏/㎡, not the Asian obesity standard of 25 ㎏/㎡, had a negative effect on the lower limb muscle strength.

Normalized Hip and Knee Strength in Two Age Groups of Adolescent Female Soccer Players

Hannon, JP, Wang-Price, S, Garrison, JC, Goto, S, Bothwell, JM, and Bush, CA. Normalized hip and knee strength in two age groups of adolescent female soccer players. J Strength Cond Res 36(1): 207-211, 2022-Limb symmetry strength measures are used for clinical decision-making considering when an athlete is ready to return to sport after anterior cruciate ligament (ACL) injuries. However, changes in bilateral muscle strength occur after ACL injury resulting in potentially altered limb symmetry calculations. Adolescent female soccer players are at increased risk of sustaining ACL injuries. Published age and sex-matched strength values in this population may be of benefit to clinicians to improve clinical decision-making. The purpose of this study was to establish normative hip and knee strength data of both the dominant and nondominant limbs in adolescent female soccer players. Sixty-four female soccer players (ages 10-18) were enrolled in this study. Subjects were divided by age into 2 groups (group 1: 10-14 years; group 2: 15-18 years). Subjects underwent Biodex isokinetic strength testing at 60°·s-1 and 180°·s-1 to assess quadriceps and hamstring strength. Isometric hip strength (abduction and external rotation) was measured using a hand-held dynamometer. No significant differences were found between groups on either limb in regards to quadriceps or hamstring strength. No significant differences were found between groups on either limb for hip external rotation strength. Significant differences in hip abduction strength were found between groups on the dominant (group 1: 0.21 ± 0.04; group 2: 0.18 ± 0.04; p = 0.014) and nondominant (group 1: 0.21 ± 0.05; group 2: 0.18 ± 0.05; p = 0.019) limbs. The results of this study shed light on normative strength values for a high-risk injury population.

Effects of motor imagery combined with action observation training on the lateral specificity of muscle strength in healthy subjects.

Unilateral training of both lateral limbs increases unilateral muscle strength, whereas bilateral training increases bilateral muscle strength, a phenomenon known as lateral specificity in resistance training. Although motor imagery (MI) combined with action observation (AO) (i.e., MI + AO) training increases muscle strength, it is not completely understood whether such training increases the lateral specificity of muscle strength in a way resistance training does. To investigate whether MI + AO induces lateral specificity of muscle strength increase, 18 healthy subjects were divided into groups: MI + AO and the control groups. The control group watched a movie of natural sceneries for ten minutes per day five times a week for three weeks, whereas the MI + AO group imagined bilateral shoulder flexion while watching a movie of athletes performing bilateral shoulder flexion with barbells or dumbbells, with the same time schedule. The MI + AO group alone showed a significant increase in bilateral shoulder strength at three weeks after the intervention compared with the baseline. Unilateral shoulder strength was not significantly altered. These results suggest that MI + AO training increases muscle strength, providing evidence that similar to resistance training, lateral specificity also exists in MI + AO training.

Neuromuscular Adaptations to Unilateral vs. Bilateral Strength Training in Women.

Botton, CE, Radaelli, R, Wilhelm, EN, Rech, A, Brown, LE, and Pinto, RS. Neuromuscular adaptations to unilateral vs. bilateral strength training in women. J Strength Cond Res 30(7): 1924-1932, 2016-Considering the bilateral deficit, the sum of forces produced by each limb in a unilateral condition is generally greater than that produced by them in a bilateral condition. Therefore, it can be speculated that performing unilateral strength exercises may allow greater training workloads and subsequently greater neuromuscular adaptations when compared with bilateral training. Hence, the purpose of this study was to compare neuromuscular adaptations with unilateral vs. bilateral training in the knee extensor muscles. Forty-three recreationally active young women were allocated to a control, unilateral (UG) or bilateral (BG) training group, which performed 2 times strength training sessions a week for 12 weeks. Knee extension one repetition maximum (1RM), maximal isometric strength, muscle electrical activity, and muscle thickness were obtained before and after the study period. Muscle strength was measured in unilateral (right + left) and bilateral tests. Both UG and BG increased similarly their unilateral 1RM (33.3 ± 14.3% vs. 24.6 ± 11.9%, respectively), bilateral 1RM (20.3 ± 6.8% vs. 28.5 ± 12.3%, respectively), and isometric strength (14.7 ± 11.3% vs. 13.1 ± 12.5%, respectively). The UG demonstrated greater unilateral isometric strength increase than the BG (21.4 ± 10.5% vs. 10.3 ± 11.1%, respectively) and only the UG increased muscle electrical activity. Muscle thickness increased similarly for both training groups. Neither group exhibited pretesting 1RM bilateral deficit values, but at post-testing, UG showed a significant bilateral deficit (-6.5 ± 7.8%) whereas BG showed a significant bilateral facilitation (5.9 ± 9.0%). Thus, performing unilateral or bilateral exercises was not a decisive factor for improving morphological adaptations and bilateral muscle strength in untrained women. Unilateral training, however, potentiate unilateral specific strength gains.

Bilateral muscle strength symmetry and performance are improved following walk training with restricted blood flow in an elite paralympic sprint runner: Case study

ObjectivesInvestigate the influence of 4 weeks of walk training with blood flow restriction (BFR) on muscle strength, metabolic responses, 100-m and 400-m performances in an athlete with cerebral palsy. MethodsAn elite Paralympic sprinter (20 years, 176 cm, 64.8 kg) who presented with moderate hemiplegic cerebral palsy (right side impaired) completed four visits before and after 4 weeks of the BFR training: 1) anthropometric measurements, familiarization of maximal voluntary contraction (MVC), and an incremental test; 2) MVC measurements; 3) 400-m performance, and 4) 100-m performance. The walk training with BFR consisted of four bouts of 5 min at 40% of maximal aerobic speed with 1 min of passive rest with complete reperfusion. ResultsAll performance times were lower with training (100-m: 1%; 400-m: 10%), accompanied by adaptations in aerobic variables (V˙O2max: 6%; OBLA: 24%) and running economy (9–10%). Lactic acid energy metabolism was reduced (25–27%), even in the presence of a higher lactate efflux from the previously active muscles after training. MVC (right leg: 19%; left leg: 9%) increased in both legs unevenly, decreasing the muscle strength asymmetry between limbs. ConclusionsThese results indicate that cardiovascular and neuromuscular adaptations can be simultaneously induced following BFR training in a paralympic sprinter.

Spontaneous cervicothoracic epidural hematoma

Spontaneous spinal epidural hematoma is a quite rare emergency situation. It is usually seen on cervical and thoracic levels and is one of the rarest causes of spinal cord compression. It usually necessitates emergency intervention because of neurologic deficit caused by cord compression. Delay of diagnosis and treatment can cause irreversible neurologic deficit and even death [1,2]. A 19-year-old male patient admitted to the emergency service with weakness in his arms and legs. Bilateral muscle strength of upper extremities was 4 of 5, and lower extremities were paraplegic at neurologic examination. Magnetic resonance imaging revealed a nonenhancing lesion compressing the cord on posterior epidural space at C7–T2 level, iso/hyperintense on T1-weighted images, and iso/hypointense on T2-weighted images (Figs. 1 and 2). It was considered to be an acute epidural hematoma. Surgery was planned because clinical findings did not regressed in 1 day. C6, C7, and T1 laminectomy confirmed the lesion as epidural hematoma. The spinal cord was decompressed by draining the hematoma. No neurologic deficit and clinical symptom were observed at postoperative second week.

The influence of Nordic walking exercise on upper extremity strength and the volume of lymphoedema in women following breast cancer treatment

The aim of this study was to examine the effect of Nordic walking on upper extremity strength and the level of lymphoedema in women following treatment for breast cancer (BC). A group of 38 women with treated BC were assigned to two groups: a study group of 23 women taking part in 8 weeks of Nordic walking and a control group of 15 women. Each participant was assessed for bilateral muscle strength using an upper limb push-pull attachment. Circumference measurement served for determination of the volume of the lymphoedema. In women after the surgical procedure on the right side statistically significant changes in the strength of pushing motion of both the right and the left were observed. In women after the surgical procedure on the left side these values were statistically significant only for the left extremity. No significant changes were demonstrated for the treated side; we did not record either the occurrence or the intensification of lymphoedema in women after BC treatment. So, Nordic walking can be considered as safe form of rehabilitation for this group of patients.

The effect of bilateral asymmetry of muscle strength on the height of a squat jump: A computer simulation study

The aim of this study was to examine the effect of bilateral asymmetry of muscle strength on maximal height of the squat jump. A computer simulation technique was used to develop two kinds of 3D human lower limb musculoskeletal model (model-symmetry and model-asymmetry). The total muscle strength of the two models was set to be identical. Bilateral muscle strength was equal in the model-symmetry simulation, while the model-asymmetry simulation was performed with a 10% bilateral strength asymmetry. A forward dynamics approach was used to simulate squat jumps. The squat jumps were successfully generated, producing jump heights of 0.389 m for model-symmetry and 0.387 m for model-asymmetry. The small difference in height (0.5%) indicated that the effect of the 10% bilateral asymmetry of muscle strength on jump height is negligible. With model-asymmetry, the strong leg compensated for the muscle strength deficit of the weak leg. Importantly, the mono-articular and large extensor muscles of the hip and knee joint of the strong leg, including the gluteus maximus, adductor magnus, and vasti, compensated for the muscle strength deficit of the weak leg.

Does the eccentric Nordic Hamstring exercise have an effect on isokinetic muscle strength imbalance and dynamic jumping performance in female rugby union players

The aim of this study was to evaluate the effect of an eccentric hamstring specific training programme on the percentage of bilateral muscle strength imbalance and maximal vertical jump height. Twenty-four, injury free female rugby union players took part in this study. Participants were split into two groups; intervention group (Nordic Hamstring (NH) (n = 13) and control group (n = 11)). Both groups completed normal training; the NH group completed a concurrent NH programme for 10 weeks. Pre and post-training concentric/concentric isokinetic testing of peak torque was performed for hamstrings of both legs at 60 ◦ /s. Vertical jump height was also assessed. In the NH group, there was a significant decrease in mean percentage bilateral hamstring strength imbalance (pre = 10.39 ± 3.53, post = 4.63 ± 2.81, p< 0.05). There was also a significant increase in vertical jump height for the NH group (pre = 31.22 ± 4.8 cm, post = 35.93 ± 4.5 cm, p< 0.05). The NH programme caused favourable adaptations to bilateral hamstring strength imbalance and dynamic lower body performance. A programme based on NH exercise is potentially an effective preventive and rehabilitation tool for hamstring injury.

The effect of bilateral asymmetry of muscle strength on jumping height of the countermovement jump: A computer simulation study

The purpose of the current study was to examine the effect of bilateral asymmetry of muscle strength on performance (maximal jumping height) of the countermovement jump. In experimental studies, it is impossible to control for muscle strength asymmetry, since it varies widely among individuals. In the current study, we used computer simulation. Two three-dimensional human lower limb neuromusculoskeletal models (model-symmetry and model-asymmetry) were developed. The total muscle strength of the two models was set to be identical. Bilateral muscle strength was set equal in the model-symmetry simulation, while the model-asymmetry simulation was set with a 10% bilateral strength asymmetry. The countermovement jumps were generated successfully, producing jumping heights of 0.416 m for model-symmetry and 0.419 m for model-asymmetry. The small difference in height (0.7%) indicates that bilateral asymmetry by itself does not have a significant effect on jumping performance. With model-asymmetry, the strong leg compensated for the muscle strength deficit of the weak leg by lateral movement of the body to distribute the load proportional to the muscle strength of each leg.