Influence of aging on isometric muscle strength,fat-free mass and electromyographic signal power of the upper and lower limbs in women

Background

Aging is a multifactorial process that leads to changes in the quantity and quality of skeletal muscle and contributes to decreased levels of muscle strength.

Objective

This study sought to investigate whether the isometric muscle strength, fat-free mass (FFM) and power of the electromyographic (EMG) signal of the upper and lower limbs of women are similarly affected by aging.

Method

The sample consisted of 63 women, who were subdivided into three groups (young (YO) n=33, 24.7±3.5 years; middle age (MA) n=15, 58.6±4.2 years; and older adults (OA). n=15, 72.0±4.2 years). Isometric strength was recorded simultaneously with the capture of the electrical activity of the flexor muscles of the fingers and the vastus lateralis during handgrip and knee extension tests, respectively. FFM was assessed using dual-energy X-ray absorptiometry.

Results

The handgrip strength measurements were similar among groups (p=0.523), whereas the FFM of the upper limbs was lower in group OA compared to group YO (p=0.108). The RMSn values of the hand flexors were similar among groups (p=0.754). However, the strength of the knee extensors, the FFM of the lower limbs and the RMSn values of the vastus lateralis were lower in groups MA (p=0.014, p=0.006 and p=0.013, respectively) and OA (p=0.000, p=0.000 and p<0.000, respectively) compared to group YO.

Conclusions

The results of this study demonstrate that changes in isometric muscle strength in MLG and electromyographic activity of the lower limbs are more pronounced with the aging process of the upper limb.     

Lower limb muscle strength is associated with functional performance and quality of life in patients with systemic sclerosis

Background:

Complaints of peripheral muscle weakness are quite common in patients with systemic sclerosis (SSc). It is likely that the muscle impairments may reduce the patients'' exercise performance, which in turn may decrease their functional capacity and exert a direct impact on their quality of life.

Objectives:

To assess the peripheral and respiratory muscle strength in individuals with SSc and to investigate their correlation with the 6-min walk distance (6MWD) and quality of life measurements. Moreover, we aimed to characterize their nutritional status, pulmonary function, functional capacity, and quality of life compared to the controls.

Method:

The present cross-sectional study included 20 patients with SSc and 20 control subjects. All of the participants were subjected to isometric dynamometry, surface electromyography, bioelectrical impedance analysis, pulmonary function testing, and the 6-min walk test. Patients with SSc also responded to the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and the Health Assessment Questionnaire Disability Index (HAQ-DI).

Results:

The individuals with SSc exhibited a reduction in quadriceps strength (p=0.0001), increased quadriceps fatigability (p=0.034), impaired pulmonary function, and a reduced 6MWD (p=0.0001) compared to the controls. Quadriceps strength was significantly correlated with the 6MWD (Rho=0.719; p=0.0004) and the HAQ-DI (Rho=-0.622; p=0.003). We also found significant correlations between quadriceps fatigability and maximal inspiratory (Rho=0.684; p=0.0009) and maximal expiratory (Rho=0.472; p=0.035) pressure.

Conclusions:

Patients with SSc exhibited reduced respiratory muscle and quadriceps strength and an increase in its fatigability. In these individuals, there was a relationship between quadriceps strength, functional capacity, and quality of life.     

Relationship between static postural control and the level of functional abilities in children with cerebral palsy

Background:

Postural control deficits can impair functional performance in children with cerebral palsy (CP) in daily living activities.

Objective:

To verify the relationship between standing static postural control and the functional ability level in children with CP.

Method:

The postural control of 10 children with CP (gross motor function levels I and II) was evaluated during static standing on a force platform for 30 seconds. The analyzed variables were the anteroposterior (AP) and mediolateral (ML) displacement of the center of pressure (CoP) and the area and velocity of the CoP oscillation. The functional abilities were evaluated using the mean Pediatric Evaluation of Disability Inventory (PEDI) scores, which evaluated self-care, mobility and social function in the domains of functional abilities and caregiver assistance.

Results:

Spearman''s correlation test found a relationship between postural control and functional abilities. The results showed a strong negative correlation between the variables of ML displacement of CoP, the area and velocity of the CoP oscillation and the PEDI scores in the self-care and caregiver assistance domains. Additionally, a moderate negative correlation was found between the area of the CoP oscillation and the mobility scores in the caregiver assistance domain. We used a significance level of 5% (p <0.05).

Conclusions:

We observed that children with cerebral palsy with high CoP oscillation values had lower caregiver assistance scores for activities of daily living (ADL) and consequently higher levels of caregiver dependence. These results demonstrate the repercussions of impairments to the body structure and function in terms of the activity levels of children with CP such that postural control impairments in these children lead to higher requirements for caregiver assistance.     

Postural alignment in children with Duchenne muscular dystrophy and its relationship with balance

Background

In Duchenne muscular dystrophy, functional deficits seem to arise from body misalignment, deconditioning, and obesity secondary to weakness and immobility. The question remains about the effects of postural deviations on the functional balance of these children.

Objectives

To identify and quantify postural deviations in children with DMD in comparison to non-affected children (eutrophic and overweight/obese), exploring relationships between posture and function.

Method

This case-control study evaluated 29 participants aged 6 to 11 years: 10 DMD (DG), 10 eutrophic (EG), and 9 overweight/obese (OG). Digital photogrammetry and SAPo program were used to measure postural alignment and the Pediatric Balance Scale (PBS) was used to measure balance. The Kruskall-Wallis and Dunn post-hoc tests were used for inter-group comparison of posture and balance. Spearman''s coefficient tested the correlation between postural and balance variables.

Results

The horizontal pelvic alignment data indicated that the anteversion of the DG was similar to that of the OG and twice that of the EG (p<0.05). Compared to the EG, the DG and OG showed an increased forward position of the center of mass (p<0.05). There was a moderate and weak correlation between the PBS score and horizontal pelvic alignment (0.58 and 0.47-left/right). The PBS showed a weak correlation with asymmetries in the sagittal plane (-0.39). The PBS scores for the OG and EG suggest that obesity did not have a deleterious effect on balance.

Conclusions

The balance deficit in children with DMD was accompanied by an increased forward position of the center of mass and significant pelvic anteversion that constitutes a compensatory strategy to guarantee similar performance to the children not affected by the disease.     

Influence of mental practice and movement observation on motor memory,cognitive function and motor performance in the elderly

Background

With aging, it is important to maintain cognitive and motor functions to ensure autonomy and quality of life. During the acquisition of motor skills, it is necessary for the elderly to understand the purpose of the proposed activities. Physical and mental practice, as well as demonstrations, are strategies used to learn movements.

Objectives

To investigate the influence of mental practice and the observation of movement on motor memory and to understand the relationship between cognitive function and motor performance in the execution of a sequence of digital movements in the elderly.

Method

This was a cross-sectional study conducted with 45 young and 45 aged subjects. The instruments used were Mini-Mental State Examination (MMSE), Manual Preference Inventory and a Digital Motor Task (composed of a training of a sequence of movements, an interval and a test phase). The subjects were divided into three subgroups: control, mental practice and observation of movement.

Results

The elderly depend more strongly on mental practice for the acquisition of a motor memory. In comparing the performances of people in different age groups, we found that in the elderly, there was a negative correlation between the MMSE score and the execution time as well as the number of errors in the motor task.

Conclusions

For the elderly, mental practice can advantage motor performance. Also, there is a significant relationship between cognitive function, learning and the execution of new motor skills.     

Comparison of functional exercise capacity,quality of life and respiratory and peripheral muscle strength between patients with stable angina and healthy controls

ObjectiveWe aimed to compare functional exercise capacity, respiratory and peripheral muscle strength, pulmonary function and quality of life between patients with stable angina and healthy controls.MethodsWe compared 33 patients with stable angina (55.21 ± 6.12 years old, Canada Class II–III, left ventricular ejection fraction: 61.92 ± 7.55) and 30 healthy controls (52.70 ± 4.22 years old). Functional capacity (6-minute walk test (6-MWT)), respiratory muscle strength (mouth pressure device), peripheral muscle strength (dynamometer), pulmonary function (spirometer) and quality of life (Short Form 36 (SF-36)) were evaluated.Results6-MWT distance (499.20 ± 51.91 m versus 633.05 ± 57.62 m), maximal inspiratory pressure (85.42 ± 20.52 cmH₂O versus 110.44 ± 32.95 cmH₂O), maximal expiratory pressure (83.33 ± 19.05 cmH₂O versus 147.96 ± 54.80 cmH₂O) and peripheral muscle strength, pulmonary function and SF-36 sub-scores were lower in the angina group versus the healthy controls, respectively.ConclusionImpaired peripheral and respiratory muscle strength, reduction in exercise capacity and quality of life are obvious in patients with stable angina. Therefore, these parameters should be considered in stable angina physiotherapy programmes to improve impairments.     

Cervical and shoulder postural assessment of adolescents between 15 and 17 years old and association with upper quadrant pain

Background:

There is sparse literature that provides evidence of cervical and shoulder postural alignment of 15 to 17-year-old adolescents and that analyzes sex differences.

Objectives:

To characterize the postural alignment of the head and shoulder in the sagittal plane of 15 to 17-year-old Portuguese adolescents in natural erect standing and explore the relationships between three postural angles and presence of neck and shoulder pain.

Method:

This cross-sectional study was conducted in two secondary schools in Portugal. 275 adolescent students (153 females and 122 males) aged 15 to 17 were evaluated. Sagittal head, cervical, and shoulder angles were measured with photogrammetry and PAS software. The American Shoulder and Elbow Surgeons Shoulder Assessment (ASES) was used to assess shoulder pain, whereas neck pain was self-reported with a single question.

Results:

Mean values of sagittal head, cervical, and shoulder angles were 17.2±5.7, 47.4±5.2, and 51.4±8.5º, respectively. 68% of the participants revealed protraction of the head, whereas 58% of them had protraction of the shoulder. The boys showed a significantly higher mean cervical angle, and adolescents with neck pain revealed lower mean cervical angle than adolescents without neck pain. 53% of the girls self-reported regular neck pain, contrasting with 19% of the boys.

Conclusions:

This data shows that forward head and protracted shoulder are common postural disorders in adolescents, especially in girls. Neck pain is prevalent in adolescents, especially girls, and it is associated with forward head posture.     

Influence of obstructive sleep apnea syndrome in the fluctuation of the submaximal isometric torque of knee extensors in patients with early-grade osteoarthritis

OBJECTIVE:

The aim of this study was to investigate whether obstructive sleep apnea (OSA) alters the fluctuation of submaximal isometric torque of the knee extensors in patients with early-grade osteoarthritis (OA).

METHOD:

The study included 60 male volunteers, aged 40 to 70 years, divided into four groups: Group 1 (G1) - Control (n=15): without OA and without OSA; Group 2 (G2) (n=15): with OA and without OSA; Group 3 (G3) (n=15): without OA and with OSA; and Group 4 (G4) (n=15) with OA and with OSA. Five patients underwent maximal isometric contractions of 10 seconds duration each, with the knee at 60° of flexion to determine peak torque at 60°. To evaluate the fluctuation of torque, 5 submaximal isometric contractions (50% of maximum peak torque) of 10 seconds each, which were calculated from the standard deviation of torque and coefficient of variation, were performed.

RESULTS:

Significant differences were observed between groups for maximum peak torque, while G4 showed a lower value compared with G1 (p=0.005). Additionally, for the average torque exerted, G4 showed a lower value compared to the G1 (p=0.036). However, no differences were found between the groups for the standard deviation (p=0.844) and the coefficient of variation (p=0.143).

CONCLUSION:

The authors concluded that OSA did not change the parameters of the fluctuation of isometric submaximal torque of knee extensors in patients with early-grade OA.     

Effect of postural insoles on static and functional balance in children with cerebral palsy: A randomized controlled study

BACKGROUND:

Improved gait efficiency is one of the goals of therapy for children with cerebral palsy (CP). Postural insoles can allow more efficient gait by improving biomechanical alignment.

OBJECTIVE:

The aim of the present study was to determine the effect of the combination of postural insoles and ankle-foot orthoses on static and functional balance in children with CP.

METHOD:

A randomized, controlled, double-blind, clinical trial. After meeting legal requirements and the eligibility criteria, 20 children between four and 12 years of age were randomly allocated either to the control group (CG) (n=10) or the experimental group (EG) (n=10). The CG used placebo insoles and the EG used postural insoles. The Berg Balance Scale, Timed Up-and-Go Test, Six-Minute Walk Test, and Gross Motor Function Measure-88 were used to assess balance as well as the determination of oscillations from the center of pressure in the anteroposterior and mediolateral directions with eyes open and closed. Three evaluations were carried out: 1) immediately following placement of the insoles; 2) after three months of insole use; and 3) one month after suspending insole use.

RESULTS:

The EG achieved significantly better results in comparison to the CG on the Timed Up-and-Go Test as well as body sway in the anteroposterior and mediolateral directions.

CONCLUSION:

Postural insoles led to an improvement in static balance among children with cerebral palsy, as demonstrated by the reduction in body sway in the anteroposterior and mediolateral directions. Postural insole use also led to a better performance on the Timed Up-and-Go Test.     

绝经妇女下肢肌力与平衡功能的相关性研究

目的:研究绝经后妇女膝关节肌力与静态平衡之间的相关性。方法:60例绝经后妇女,分别用PJ-I型电脑平衡功能检测仪测定静态平衡功能,Cybex-330等速肌力测试仪测试膝关节肌力,将所测定的平衡功能参数与肌力参数做相关性分析,按年龄分为65岁以下(含65岁)以及65岁以上年龄组,每组组内进行肌力与平衡功能相关性分析。结果:总体上静态平衡功能与下肢肌力之间无直线相关,按年龄分组后,65岁以上年龄组平衡功能与下肢肌力间存在相关性。结论:年龄相关的平衡功能减退涉及的因素繁杂,单纯膝关节肌力下降一般不至于引起显著的静态平衡功能低下。     

Difference in postural stability between STarT Back Tool subgroups of patients with low back pain under conditions of sensory deprivation and cognitive load

ObjectiveWe explored differences in postural stability between subgroups of patients with low back pain (LBP) and varying risk levels for developing chronicity measured using the Subgroups for Targeted Treatment (STarT) Back Tool.MethodsThis was a cross-sectional, single-session, double-blind experimental study among 65 participants who had LBP for more than 14 days. Postural stability was assessed by measuring the center of pressure (COP) range, displacement area, and velocity in anterior–posterior and mediolateral directions under four sensory and cognitive conditions: (i) eyes open and counting forward, (ii) eyes closed and counting forward, (iii) eyes closed and counting forward in multiples of seven, and (iv) eyes closed and counting backward in multiples of seven. The participants were stratified into low-/medium- (n = 53) and high-risk (n = 9) subgroups.ResultsThere were no significant between-group differences among patients with LBP stratified as having a low/medium or high risk of chronicity in postural stability and sensory and cognitive conditions.ConclusionsImpaired postural stability is important to consider when treating patients with LBP. However, we found that these impairments were not strongly aggravated in groups with a higher risk of chronicity, as measured using the STarT Back Tool.     

Prospective monitoring and self-report of previous falls among older women at high risk of falls and fractures: a study of comparison and agreement

Background:

The identification of the occurrence of falls is an important step for screening and for rehabilitation processes for the elderly. The methods of monitoring these events are susceptible to recording biases, and the choice of the most accurate method remains challenging.

Objectives:

(i) To investigate the agreement between retrospective self-reporting and prospective monitoring of methods of recording falls, and (ii) to compare the retrospective self-reporting of falls and the prospective monitoring of falls and recurrent falls over a 12-month period among older women at high risk of falls and fractures.

Method:

A total of 118 community-dwelling older women with low bone density were recruited. The incidence of falls was monitored prospectively in 116 older women (2 losses) via monthly phone calls over the course of a year. At the end of this monitoring period, the older women were asked about their recall of falls in the same 12-month period. The agreement between the two methods was analyzed, and the sensitivity and specificity of self-reported previous falls in relation to the prospective monitoring were calculated.

Results:

There was moderate agreement between the prospective monitoring and the retrospective self-reporting of falls in classifying fallers (Kappa=0.595) and recurrent fallers (Kappa=0.589). The limits of agreement were 0.35±1.66 falls. The self-reporting of prior falls had a 67.2% sensitivity and a 94.2% specificity in classifying fallers among older women and a 50% sensitivity and a 98.9% specificity in classifying recurrent fallers.

Conclusion:

Self-reporting of falls over a 12-month period underestimated 32.8% of falls and 50% of recurrent falls. The findings recommend caution if one is considering replacing monthly monitoring with annual retrospective questioning.     

Effect of two different kinesio taping techniques on knee kinematics and kinetics in young females

[Purpose] The application of kinesio taping may improve strength and performance, inhibit and facilitate motor activity, and increase range of motion. The aim of this study was to compare the effects of kinesio taping facilitation and inhibition applications on spatiotemporal knee kinematics and kinetics during walking activity in healthy subjects. [Subjects and Methods] A three-dimensional quantitative gait evaluation was performed without tape and with, facilitation and inhibition kinesio taping application on the knee. Sixteen healthy female college students (age, 19.7 ± 0.4 years; height, 1.64 ± 3.4 cm; body mass, 51.5 ± 4.8 kg) participated in the study. [Results] Spatiotemporal parameters (cadence, walking speed, stride length) were significantly different among the trials. Knee joint sagittal plane range of motion was not different with either kinesio taping application. Knee external flexion moment during the early stance phase decreased significantly with facilitation kinesio taping and increased with the inhibition kinesio taping. Knee external extension moment during the mid-stance phase increased with facilitation kinesio taping. Knee power parameters, eccentric activity in the rectus femoris during the pre-swing phase was significantly increased with inhibition kinesio taping application, while eccentric activity of the hamstrings during the terminal swing of gait was decreased. [Conclusion] These findings showed that facilitation kinesio taping application affected the terminal stance phase and that inhibition kinesio taping influenced the terminal swing phase compared with the no tape condition.Key words: Kinesio tape, Knee joint, Gait analysis     

Pelvic floor muscle training and postural balance in elderly women: An exploratory single arm trial

IntroductionTo investigate the influence of a training of mobility, gait speed and postural balance of pelvic floor muscles (PFM).MethodsA single-arm clinical trial study was approved and registered at the Brazilian Clinical Trials Registry (RBR-4rxhd4). Eighteen women over the age of 60 with pelvic floor dysfunction complaints were subjected to 10 sessions of functional electrical stimulation and digital palpation of PFM. Mobility and gait speed were evaluated by the Timed up and Go and the 10-m walk tests respectively. Standing balance was evaluated using a force plate.ResultsNo significant differences were found in mobility, gait speed, and standing balance. PFM contraction worsened mobility, gait speed, and standing balance performance.ConclusionsThe training protocol enhanced PFM strength and endurance, but the improved ability to recruit PFM did not positively affect balance, mobility, and gait speed.     

Interval and continuous exercise enhances aerobic capacity and hemodynamic function in CHF rats

OBJECTIVE:

The aim of the present study was to compare the effects of continuous versus interval aerobic exercise training on hemodynamic parameters, cardiac remodeling, and maximal exercise capacity (MEC) in chronic heart failure (CHF) rats.

METHOD:

Twenty-four male Wistar rats were subjected to myocardial infarction (MI) surgery. Five weeks post MI, the animals were assigned to one of three groups: sedentary group (CHF-Sed, n=8), aerobic continuous training group (CHF-ACT, n=8), and aerobic interval training group (CHF-AIT, n=8). Treadmill training was performed five times a week for 8 weeks (ACT: 50 min/day at 15 m/min and AIT: 40 min/day with 8 min of warm-up at 10 m/min and exercise at 15 m/min 4×4 min interspersed with 4×4 min at 23 m/min). MEC was evaluated pre and post exercise program.

RESULTS:

Left ventricular end-diastolic pressure (LVEDP), left ventricular mass/body mass ratio (LVM:BM), and total collagen volume fraction were lower in the trained groups compared with the sedentary group, but no difference was found between the trained groups. Systolic ventricular pressure (SVP) and maximum positive derivative of LV pressure (+dP/dt_max) were higher in the trained groups, but CHF-ACT showed higher +dP/dt_max compared to CHF-AIT. Both training regimens were able to increase MEC. However, the aerobic interval training was superior for improving MEC.

CONCLUSION:

Aerobic training is an important intervention to improve cardiac function and remodeling and physical capacity in CHF rats. Interval training is a potential strategy to maximize the results, but exercise type and intensity are still topics to be explored.     

Joint positioning sense,perceived force level and two-point discrimination tests of young and active elderly adults

Background:

Changes in the proprioceptive system are associated with aging. Proprioception is important to maintaining and/or recovering balance and to reducing the risk of falls.

Objective:

To compare the performance of young and active elderly adults in three proprioceptive tests.

Method:

Twenty-one active elderly participants (66.9±5.5 years) and 21 healthy young participants (24.6±3.9 years) were evaluated in the following tests: perception of position of the ankle and hip joints, perceived force level of the ankle joint, and two-point discrimination of the sole of the foot.

Results:

No differences (p>0.05) were found between groups for the joint position and perceived force level. On the other hand, the elderly participants showed lower sensitivity in the two-point discrimination (higher threshold) when compared to the young participants (p < 0.01).

Conclusion:

Except for the cutaneous plantar sensitivity, the active elderly participants had maintained proprioception. Their physical activity status may explain similarities between groups for the joint position sense and perceived force level, however it may not be sufficient to prevent sensory degeneration with aging.