Hugo M. Pereira

Comparing the Pilates method with no exercise or lumbar stabilization for pain and functionality in patients with chronic low back pain: Systematic review and meta-analysis

Objective: To perform a systematic review with meta-analyses that evaluates the effectiveness of the Pilates method on the pain and functionality outcome in adults with non-specific chronic low back pain. Data sources: The search was performed in the following databases: Medline, Embase, AMED, Cinahl, Lilacs, Scielo, SportDiscus, ProQuest, Web of Science, PEDro, Academic Search Premier and the Cochrane Central Register of Controlled Trials from 1950 to 2011; the following keywords were used: ‘Pilates’, ‘Pilates-based’, ‘back exercises’, ‘exercise therapy’, ‘low back pain’, ‘back pain’ and ‘backache.’ Review methods: The inclusion criteria were studies that assessed the effects of the Pilates method on patients with chronic low back pain. Results: Five studies met the inclusion criteria. The total number of patients was 71 in the Pilates group and 68 in the control group. Pilates exercise did not improve functionality (standardized mean difference (SMD = –1.34; 95% confidence interval (CI) −2.80, 0.11; P = 0.07) or pain between Pilates and control groups (SMD = –1.99; 95% CI −4.35, 0.37; P = 0.10). Pilates and lumbar stabilization exercises presented no significant difference in functionality (mean difference (MD) = –0.31; 95% CI −1.02, 0.40; P = 0.39) or pain (MD = –0.31; 95% CI −1.02, 0.40; P = 0.39). Conclusion: The Pilates method did not improve functionality and pain in patients who have low back pain when compared with control and lumbar stabilization exercise groups.

The aging neuromuscular system and motor performance

Age-related changes in the basic functional unit of the neuromuscular system, the motor unit, and its neural inputs have a profound effect on motor function, especially among the expanding number of old (older than ∼60 yr) and very old (older than ∼80 yr) adults. This review presents evidence that age-related changes in motor unit morphology and properties lead to impaired motor performance that includes 1) reduced maximal strength and power, slower contractile velocity, and increased fatigability; and 2) increased variability during and between motor tasks, including decreased force steadiness and increased variability of contraction velocity and torque over repeat contractions. The age-related increase in variability of motor performance with aging appears to involve reduced and more variable synaptic inputs that drive motor neuron activation, fewer and larger motor units, less stable neuromuscular junctions, lower and more variable motor unit action potential discharge rates, and smaller and slower skeletal muscle fibers that coexpress different myosin heavy chain isoforms in the muscle of older adults. Physical activity may modify motor unit properties and function in old men and women, although the effects on variability of motor performance are largely unknown. Many studies are of cross-sectional design, so there is a tremendous opportunity to perform high-impact and longitudinal studies along the continuum of aging that determine 1) the influence and cause of the increased variability with aging on functional performance tasks, and 2) whether lifestyle factors such as physical exercise can minimize this age-related variability in motor performance in the rapidly expanding numbers of very old adults.

Stressor-induced increase in muscle fatigability of young men and women is predicted by strength but not voluntary activation

This study investigated mechanisms for the stressor-induced changes in muscle fatigability in men and women. Participants performed an isometric-fatiguing contraction at 20% maximal voluntary contraction (MVC) until failure with the elbow flexor muscles. Study one (n = 55; 29 women) involved two experimental sessions: 1) a high-stressor session that required a difficult mental-math task before and during a fatiguing contraction and 2) a control session with no mental math. For some participants (n = 28; 14 women), cortical stimulation was used to examine mechanisms that contributed to muscle fatigability during the high-stressor and control sessions. Study two (n = 23; nine women) determined the influence of a low stressor, i.e., a simple mental-math task, on muscle fatigability. In study one, the time-to-task failure was less for the high-stressor session than control (P < 0.05) for women (19.4%) and men (9.5%): the sex difference response disappeared when covaried for initial strength (MVC). MVC force, voluntary activation, and peak-twitch amplitude decreased similarly for the control and high-stressor sessions (P < 0.05). In study two, the time-to-task failure of men or women was not influenced by the low stressor (P > 0.05). The greater fatigability, when exposed to a high stressor during a low-force task, was not exclusive to women but involved a strength-related mechanism in both weaker men and women that accelerated declines in voluntary activation and slowing of contractile properties.

Motor Variability during Sustained Contractions Increases with Cognitive Demand in Older Adults

To expose cortical involvement in age-related changes in motor performance, we compared steadiness (force fluctuations) and fatigability of submaximal isometric contractions with the ankle dorsiflexor muscles in older and young adults and with varying levels of cognitive demand imposed. Sixteen young (20.4 ± 2.1 year: 8 men, 9 women) and 17 older adults (68.8 ± 4.4 years: 9 men, 8 women) attended three sessions and performed a 40 s isometric contraction at 5% maximal voluntary contraction (MVC) force followed by an isometric contraction at 30% MVC until task failure. The cognitive demand required during the submaximal contractions in each session differed as follows: (1) high-cognitive demand session where difficult mental math was imposed (counting backward by 13 from a 4-digit number); (2) low-cognitive demand session which involved simple mental math (counting backward by 1); and (3) control session with no mental math. Anxiety was elevated during the high-cognitive demand session compared with other sessions for both age groups but more so for the older adults than young adults (p  < 0.05). Older adults had larger force fluctuations than young adults during: (1) the 5% MVC task as cognitive demand increased (p  = 0.007), and (2) the fatiguing contraction for all sessions (p  = 0.002). Time to task failure did not differ between sessions or age groups (p  > 0.05), but the variability between sessions (standard deviation of three sessions) was greater for older adults than young (2.02 ± 1.05 vs. 1.25 ± 0.51 min, p  < 0.05). Thus, variability in lower limb motor performance for low- and moderate-force isometric tasks increased with age and was exacerbated when cognitive demand was imposed, and may be related to modulation of synergist and antagonist muscles and an altered neural strategy with age originating from central sources. These data have significant implications for cognitively demanding low-force motor tasks that are relevant to functional and ergonomic in an aging workforce.

Avaliação da confiabilidade e usabilidade de três diferentes programas computacionais para a análise fotogramétrica do ângulo de flexão de quadril

A analise fotogrametrica pode ser feita por meio de diferentes programas computacionais. Assim, o objetivo do presente estudo foi avaliar a confiabilidade e usabilidade de tres diferentes programas em uma analise fotogrametrica durante a flexao do quadril e discutir aspectos qualitativos e quantitativos de cada um deles. Participaram do estudo 26 voluntarios do genero masculino, com idade entre 19 e 30 anos (x=25,4 anos, DP=2,5) que realizaram o teste do sentar e alcancar por meio do banco de Wells adaptado. Marcadores cutâneos foram posicionados nos processos osseos: trocânter maior do femur e espinha iliaca anterossuperior. A aquisicao da imagem foi realizada no limite maximo da execucao do teste. Todos os programas apresentaram uma alta confiabilidade entre as medidas, alem disso, foram apresentadas vantagens e desvantagens especificas na adocao de cada um deles. O programa SAPO foi considerado com maiores vantagens para utilizacao na pratica profissional, no entanto, para realizacao de analises em pesquisas cientificas todos os programas apresentam pontos que devem ser considerados antes da sua adocao.

Time-of-Day Effect on Hip Flexibility Associated with the Modified Sit-and- Reach Test in Males

Flexibility is a key component of physical fitness. It has been suggested that measures of physical fitness components may vary throughout the day. The aim of this study was to analyse the effects of the time of day on flexibility performance. 26 men (mean age=25.4 years, SD=2.5) were evaluated by hip flexion on kinematic analysis and also by an absolute score in the modified Sit-and-Reach test during a repeated measure design. This was done during 3 experimental sessions, which took place at 8:00 a.m., 1:00 p.m. and 6:00 p.m., in random order. All subjects were previously familiarized with the test parameters. There was a diurnal variation only in the modified Sit-and-Reach test score between 8:00 a.m and 6:00 p.m. (P=0.01). There was no significant difference in the hip kinematic analysis between hours. These findings suggest that flexibility performance in the modified Sit-and-Reach test, in absolute scores, is affected by the time of day, with higher performance in the evening.

Comparison of the electrical activity in upper trapezius and wrist extensor muscles during two typewriting conditions

Introduction The proper use of the position of the arm and wrist while typing may reduce muscle overload and prevent musculoskeletal disorders.Objective To evaluate the electromyographic activity of upper trapezius and wrist extensor muscles during two typewriting conditions.Materials and methods : Six healthy females (Xage = 42 years,SD= 10), (Xheight = 1.65m, SD = 0.05) and (Xweight = 71kg, SD = 16) participated in this study. The task was performed with a newly developed arm support and without the support. A perceived exertion scale was used with all subjects. An ANOVA with repeated measures was used to verify differences in perceived exertion and root mean square (RMS).Results There were no statistically significant differences for the RMS between the typewriting tasks. The condition without arm support presented a significantly greater mean velocity and amount of words typed (P= 0.02; P= 0.03) and there was a significant difference in perceived exertion during the condition without arm support (P= 0.03). Electromyographic activity did not present differences.Conclusion The muscle electrical activity was not altered regardless the arm support and occurred the improvement of the perceived exertion after 10 minutes of typing without support. Long-term studies are needed.

Força de preensão manual de atletas tenistas avaliada por diferentes recomendações de teste

It is important to assess the handgrip strength (HS) in competitive tennis players due to asymmetry between the dominant and contra lateral hands that players might develop. In order to assess HS, clinicians can use two protocols already established that are different from each other (from European Test of Physical Fitness Handbook [Eurofit] or American Society of Hand Therapists [ASHT]. The objective of this study was threefold: Firstly to compare the HS using the Eurofit and ASHT technique; secondly to compare HS between dominant/nondominant hands, and last, to compare the handgrip between ages of juvenile tennis player athletes. 137 male and 45 female tennis players (aged between 8 and 18 years) participated in the study. In order to assess HS following the Eurofit and ASHT recommendations, a Jamar dynamometer was used. None of the athletes had any injury that could compromise tests. There was no difference in handgrip strength between Eurofit and ASHT recommendations regardless of sex. The best curve to describe the regression of HS and age for both genders was a sigmoid function. Males presented a higher slope at 11 years and females had a higher slope at 10 years. Moreover, in male athletes dominant HS presented higher values than non-dominant HS beginning at 14 years. However, for the females the asymmetry in HS did not occur for any age until 18 years.

Force Steadiness During a Cognitively Challenging Motor Task Is Predicted by Executive Function in Older Adults

Motor performance and cognitive function both decline with aging. Older adults for example are usually less steady for a constant-force task than young adults when performing low-intensity contractions with limb muscles. Healthy older adults can also show varying degrees of cognitive decline, particularly in executive function skills. It is not known, however, whether age-related changes in steadiness of low-force tasks and cognitive function are independent of one another. In this study, we determined if executive function skills in aging are associated with the steadiness during a low-force muscle contraction performed with and without the imposition of a cognitive challenge. We recruited 60 older adults (60–85 years old, 34 women, 26 men) and 48 young adults (19–30 years old, 24 women, 24 men) to perform elbow flexor muscle contractions at 5% of maximal voluntary contraction (MVC) force in the presence and absence of a difficult mental-math task (counting backward by 13 from a four-digit number). Force steadiness was quantified as the coefficient of variation (CV) of force and executive function was estimated with the Trail-making Test part A and B. The cognitive challenge increased the CV of force (i.e., decreased force steadiness) with greater changes in older adults than young adults (5.2 vs. 1.3%, respectively, cognitive challenge × age: P < 0.001). Older adults were 35% slower in both parts A and B of the Trail-making Test (P < 0.001), and to eliminate the effects of age and education on this variable, all further analyses were performed with the age-corrected z-scores for each individual using established normative values. Hierarchical regression models indicated that decreased force steadiness during a cognitive challenge trial was in part, explained by the performance in the Trail-making Test part A and B in older (r = 0.53 and 0.50, respectively, P < 0.05), but not in young adults (P > 0.05). Thus, healthy community-dwelling older adults, who have poorer executive function skills, exhibit reduced force steadiness during tasks when also required to perform a high cognitive demand task, and are likely at risk of reduced capacity to perform daily activities that involve cognitively challenging motor tasks.

Understanding the mechanisms of neuromuscular fatigue with paired-pulse stimulation

Transcranial magnetic stimulation (TMS), using both single and paired-pulse techniques, has provided insight in understanding the balance of excitation and inhibition within the corticomotor system during maximal and submaximal exercise. A single pulse of TMS produces a short-latency motor-evoked potential (MEP), indicating the net excitation of the motor pathway which includes the balance within supraspinal (cortical) and spinal sources. The MEP is followed by an interruption of ongoing electromyographic (EMG) activity known as the silent period. Classically, the silent period has been interpreted to represent the inhibition within the motor cortex (i.e. intracortical inhibition) which probably involves γ-aminobutyric acid (GABAB) receptors. Intracortical inhibition is clinically important to understand because chronic pain disorders (migraines) and psychiatric disorders (post-traumatic stress disorder) have demonstrated less cortical inhibition during a voluntary contraction while other disorders such as Parkinsons and Alzheimers diseases have demonstrated abnormal corticospinal excitatory circuits at rest. Additionally, the fatigue-induced reduction in cortical inhibition may be related to the motor impairments during exercise. The alterations in the MEP and silent period during exercise indicate that the central nervous system (CNS) may necessitate increases in both excitatory and inhibitory activity during fatiguing contractions; however, the mechanisms underlying these effects are yet to be completely understood.