Impact of two different dual tasks on obstacle crossing in elderly

O desempenho de uma dupla tarefa pode aumentar o risco de quedas durante a marcha em idosos. O impacto de uma dupla tarefa pode depender de sua complexidade em relação ao processamento de informação. Diferentes configurações de duplas tarefas deduzem diferentes demandas para o processamento de informação. Neste estudo investigamos se diferentes configurações de duplas tarefas podem afetar o desempenho da transposição de obstáculo na marcha de idosos. Dez idosos independentes foram avaliados durante a marcha cruzando um obstáculo vertical enquanto desempenhando duas duplas tarefas: (a) com input auditório (variação da tarefa de Stroop), e (b) sem imput auditório (falar os dias da semana em ordem reversa). Nós hipotetizamos que um efeito da dupla tarefa seria relacionado com o tipo de seu input, e o input auditório requereria maior processamento de informação; portanto, poderia ter maior impacto na marcha. Nós encontramos que o desempanho de transpor obstáculo foi similar nas duas condições de dupla tarefa. Sendo assim, ambas duplas tarefas testadas afetam a transposição de obstáculo na mesma medida em idosos.El desempeño de una doble tarea puede aumentar el riesgo de caídas durante la marcha en personas mayores. El impacto de una doble tarea puede depender de su complejidad en cuanto al procesamiento de información. Las distintas configuraciones de dobles tareas infieren distintas demandas para dicho procesamiento. En este estudio se investigó si las distintas configuraciones de dobles tareas pueden afectar el rendimiento de la transposición de obstáculo en la marcha de personas mayores. Han participado diez personas mayores independientes y evaluadas durante la marcha cruzando un obstáculo vertical mientras hacían dos dobles tareas: (a) con input auditorio (variación de la tarea de Stroop) y (b) sin input auditorio (hablar los días de semana en orden reverso). Se dedujo que el rendimiento de la doble tarea estaría relacionado con el tipo de su input, y el input auditorio exigía un mayor procesamiento de información; por lo tanto, podría tener un mayor impacto en la marcha. Se encontró que el rendimiento en la superación de obstáculos fue semejante en las dos condiciones de doble tarea evaluadas. Así, ambas afectan a la superación del obstáculo en igual medida en personas mayores.The performance of a dual task increases risk of falling during walking in the elderly. Such impact of a dual task may depend on its complexity regarding information processing. Therefore, different dual task configurations may elicit different demands for information processing. We investigated whether different dual task configurations can differently affect the performance of obstacle crossing in the gait of elderly. Ten independent elderly performed vertical obstacle crossing while performing two dual tasks during walking: (a) with auditory input (variation of Stroop task), and (b) without auditory input (report the days of the week in reverse sequence). We hypothesized that a dual task effect would be related with the type of dual task input, and the auditory input would require further information processing and therefore could have larger impact on gait. We found that performance of obstacle crossing was similar regardless of the dual task configuration. Both dual task conditions affect the obstacle crossing in the same extent in the elderly

EXTERNAL WORK BILATERAL SYMMETRY DURING INCREMENTAL CYCLING EXERCISE

The aim of the present study was to compare the bilateral external work and torque at four stages of an incremental maximal cycling. Eleven cyclists were evaluated on a cycle ergometer. Four stages of the incremental cycling workload were defined as 60, 75, 90 and 100% of maximal oxygen uptake (VO2Max). Pedal forces and kinematics variables were measured through each stage. Crank torque and external work were computed (both sides). Crank work and torque increased throughout the incremental test. There were no differences between legs in relation to work and torque at the crank. The high variability of force symmetry between subjects, and between days may indicate the difference of our results compared to previous studies

COMBINATIONS OF CLINICAL TESTS PREDICT FRONTAL PLANE KNEE ANGLE AND MOMENT IN BILATERAL DROP JUMP

This project investigates whether performance in clinical tests can predict frontal plane knee angle and moment during bilateral drop jumps. Fifty-one recreational male athletes were assessed during clinical tests [lunge, star excursion balance test (SEBT), lateral step down (LSD), hop tests, and knee and hip isometric strength] and biomechanical assessment (3D kinematics and kinetics of bilateral drop jump). Linear regression models determined the predictive capacity of clinical tests to predict biomechanical outcomes. SEBT, triple hop test, LSD and lunge predicted frontal plane knee angle and moment with predictive power from 26 to 45%. A combination of at least two clinical tests significantly improves prediction of frontal plane knee angle and moment during bilateral drop jump. LSD, triple hop test and SEBT provide prediction for frontal plane knee angle and moment

BIOMECHANICAL DIFFERENCES DURING LANDING BETWEEN INDIVIDUALS WITH PROXIMAL AND COMBINED DEVIATIONS DURING LATERAL STEP DOWN

We investigated the 3D biomechanical differences during landing between those who have proximal (PRO) only (frontal pelvis drop down) and combined (COM) proximal and distal (frontal pelvis drop down and medial knee displacement to 2nd toe) deviations during the lateral step down (LSD) test. Sixty-one recreational male athletes were assessed and those who met the criteria for the groups were tested in a 3D biomechanical laboratory (bilateral drop jump, unilateral forward and drop jump). We found higher hip abduction in the COM group during bilateral drop landings. The COM group also showed lower peak ground reaction force, higher impact absorption rate and higher knee frontal angular velocity during unilateral landings. Participants with LSD proximal and combined deviations differ on key kinetics during unilateral drop landings and hip kinematics during bilateral drop landings

ANALYSIS OF PEDALING TECHNIQUE DURING A MAXIMAL CYCLING EXERCISE

The purpose of this study was to analyze the effects of the fatigue process during a maximal cycling exercise on the pedaling technique. Eight elite competitive male cyclists were evaluated in a two days protocol. On day 1, the cyclists were submitted to a VO2MAX test, and on day 2, they cycled to exhaustion on a cycle ergometer equipped with two 2-D pedals dynamometer to measure the forces applied on the pedals. The workload was set at 100% of their VO2MAX, as measured on day 1. The resultant and effective forces were calculated from normal and tangential forces to obtain the index of effectiveness (IE). No differences were observed in the IE throughout the entire test. This study suggests that under a fatigue protocol, elite cyclists are able to sustain the IE, which can be an important strategy in order to sustain the power output

IMPLICAÇÕES DO EXERCÍCIO REGULAR SOBRE O CONTROLE POSTURAL EM IDOSOS

Objetivo: identificar as implicações do exercício regular sobre o controle postural em idosos. Método: revisão integrativa da literatura desenvolvida nas bases de dados SCOPUS e SciELO, utilizando os descritores “postural balance” or “postural control” or “balance” and “aged”, nos últimos cinco anos e nos idiomas português ou inglês. Resultados: dos 23 estudos selecionados, identificou-se uma prevalência de estudos no ano de 2012 e nos periódicos Brazilian Journal of Physical Therapy e Revista Brasileira de Geriatria e Gerontologia. Os estudos foram agrupados em duas categorias: 1) Implicações da prática de atividade física sobre o controle postural; e 2) Exercícios físicos capazes de atuar sobre o controle postural. Conclusões: o exercício implica de maneira positiva sobre o controle postural, atuando em múltiplos aspectos motores e cognitivos, desde que seja realizado de maneira regular e com intensidade adequada para que a fadiga muscular não acarrete aumento no risco de quedas

PEDALLING KINEMATICS OF CYCLING WITH ROTOR® CRANKS

The purpose of this study was to investigate the 3-D pedaling kinematics of cycling using a Rotor RSIV and a conventional crank system. Five trained cyclists cycled at their preferred cadence and power output of 300 W using Rotor (ROT) and conventional (CON) cranks. The hip, knee and ankle flexion/extension, shank rotation, foot adduction/abduction, and pedal angle were analyzed employing 3-D kinematics. The range of motion (ROM) using the two crank systems were compared by the Student ttest. The ROM was statistically different (

Spectral properties of muscle activation during incremental cycling test

It is uncertain whether fatigue and workload would affect muscle recruitment during cycling. To infer on changes in priority for recruitment of motor units, we assessed the combined effects of fatigue and workload during an incremental cycling test to exhaustion on frequency components of lower limbs muscle activation. Competitive cyclists performed an incremental maximal cycling test while muscle activations were recorded from the right and left vastus lateralis, biceps femoris and gastrocnemius medialis. Muscle activation signals were assessed using frequency band analyses and decomposed into overall, high and low frequency bands. Combined effects from workload/fatigue were assessed using t tests and Cohen¿s effect sizes (ES). There were increases in the overall muscle activation due to increased workload/fatigue for biceps femoris (40% vs. 90%, p<0.01 and ES = 1.85) and vastus lateralis (40% vs. 70%, p=0.01 and ES = 0.96, and 40% vs. 90%, p<0.01 and ES = 2.03, and 70% vs. 90%, p<0.01 and ES = 0.96), but not for gastrocnemius medialis. There was also greater contribution from low frequency component for biceps femoris (40% vs. 90%, p = 0.01 and ES = 1.12). Similar workload/fatigue effects have been observed between lower limbs. In conclusion, incremental cycling test lead to an increase in activation of main knee joint flexors and extensors but not in plantar flexors during cycling. Biceps femoris changes its recruitment profile due to increases in low frequency content

Neuromuscular and functional responses to concentric and eccentric strength training in older adults: A systematic review

The type of muscle action is important when designing exercise interventions for older individuals and may result in different effects. In this study we performed a systematic review of controlled trials comparing the effects of concentric and eccentric resistance training, performed on isokinetic dynamometers, on lower extremity muscular and functional performance in older adults (CDR42017075316). Six databases (Pubmed, CINAHL, SPORTDiscus, PEDro, Cochrane Central, and Embase) were searched. Outcomes of interest concerned neuromuscular and functional performance. Trials should consider 65 years or older individuals participating in concentric and/or eccentric training on isokinetic dynamometers, at least twice a week, during at least four weeks. Results should be compared to a control group or between different contraction types. A qualitative analysis of data was done. Quality assessment considered the Cochrane Risk of Bias Tool. The initial search returned 10376 studies and four trials were considered for inclusion. Three trials compared the effects of concentric training with the ones of control groups, and one compared the effects of concentric with the ones of eccentric training. All trials focused on knee extensor and flexor muscles, and one also focused on ankle dorsiflexors and plantarflexors. Training programs included three sessions/week lasting 8-12 weeks. Concentric training improved strength, power, and muscle antagonist coactivation compared to the control. Concentric and eccentric training improved knee isometric, concentric and eccentric strength and scores on self-paced step test, with no effect on gait speed. They did not consider muscle structural parameters. The findings of beneficial effects of isokinetic concentric and eccentric resistance training on muscle strength and power in older adults were consistent. However, there is a lack of trials addressing the effects of isokinetic strength training on muscle structure and functionality

Importance of static adjustment of knee angle to determine saddle height in cycling

Knee flexion angle is used to determine saddle height during pedaling. However, it is unclear if knee flexion angle at upright standing posture affects measures and interpretation of knee flexion angle during cycling. The objective of this study was to assess the importance of adjusting knee angle during pedaling according to the knee angle at upright posture. Seventeen cyclists performed three 10 min cycling trials at different saddle heights to induce knee flexion angles (40º, 30º or 20º when crank was at the 6 o'clock position). Knee flexion angle was determined at the sagittal plane during cycling using a 2D motion analysis system. Alteration of saddle height was performed by subtracting the knee flexion angle determined during an upright standing posture from the observed knee flexion angle during cycling. Repeatability of knee angles at upright posture in the three trials was very good (ICC=0.73). A reduction in knee flexion angle of 10.6° (95%CI [8.6, 12.6º]) during cycling was found using the adjustment for upright standing posture (p3.0). As a result, saddle height is affected by adjustments based on knee angle measured in upright standing posture. Determining saddle height without adjusting knee angle for upright standing posture could lead to errors with possible effects on performance and/or injury risk