Unrestrained Versus Vertically Restrained Loaded Countermovement Jumps: Are There Any Differences in the Components of Force Application?

The objective of this study was to compare a number of variables derived from the vertical and horizontal force components between loaded countermovement jumps performed in a Smith machine (SM modality; vertically restrained jumps) and with free weights (FW modality; unrestrained jumps). Twenty-three recreationally trained individuals, 6 women and 17 men, performed on a 3D force platform 5 maximal countermovement jump trials against 3 external loads (30%, 50%, and 70% of the SM 1-repetition maximum) using the SM and FW jumping modalities on separate sessions. The SM modality promoted greater values for virtually all the variables derived from the vertical force component (maximal force, maximal and minimum velocity, and impulse) and also shorter durations of the braking and propulsive phases. Regardless of the countermovement jump phase (braking or propulsive), the impulse directed toward the backward direction was always considerably greater for the SM compared with the FW modality. These results evidence that for recreationally trained individuals, the SM modality could be more effective to increase the general force capacity of the leg muscles due to increased external stability, while the FW modality is preferable when the orientation of force application is a crucial consideration, as it reduces the horizontal force component.

Effectiveness of a Cognitive-Motor Training Program in Reducing Attentional Cost During Walking in Patients With Multiple Sclerosis.

The purpose of this study was to assess the efficacy of a combined training program (CTP) in reducing the effects of dual tasking on the temporal parameters and kinematics of gait, as compared with single-task gait. A controlled, randomized, intervention study was performed in an intervention group and a control group. The intervention group attended three weekly CTP sessions for 24 weeks. Gait pattern was evaluated prior to the baseline intervention, at 12 weeks, and at 24 weeks (Repost). The sample was composed of 22 subjects diagnosed with multiple sclerosis with an Expanded Disability Status Scale score of 0-5.5. A total of 12 patients were allocated to the intervention group and another 10 to the control group. A three-dimensional photogrammetry scanner was connected to a selective attention system designed to present a dual-task gait condition. Dual tasking had an impact on all spatiotemporal parameters of gait, and the most remarkable effect of dual tasking was on double-support time, which increased by 9% with respect to normal walking. In contrast, dual tasking had a trivial effect on single-support time. The CTP was effective in reducing the effects of dual tasking on stride length and velocity of the center of mass after Repost of training (p < .05). The CTP reduced time in double-support phase, whereas single-support time increased after Repost of intervention. The application of the CTP had no effect on the cost of the double task after 12 weeks of intervention. It is suggested to increase the application time over Repost.

Employability skills, quality of life, and body composition on employment modalities in individuals with mild and moderate intellectual disabilities.

Background: The inclusion of individuals with intellectual disabilities into the labour market is a challenge in advanced societies, with only a very reduced percentage of these individuals being able to access the free labour market. Whilst some progress has recently been made, there is still a need to further explore the different conditioning factors. Method: A total of 125 users belonging to the three employment modalities of Occupational Workshops (OW), Occupational Centers (OC) and Supported Employment (SE), participated in this study. Differences between modalities were determined for employability, quality of life, and body composition. Results: Employability skills were higher for SE compared to OW and OC; the index of quality of life was higher for OC and SE groups compared to OW; no differences were found in body composition between groups. Conclusions: The quality-of-life index was higher for participants performing remunerated employment modalities and employment skills increased when work was more inclusive.

The influence of meaningful activities in the quality of life and functional autonomy of adults with intellectual disability: A prospective study during the COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic might negatively impact the quality of life and functional autonomy of Spanish adults with intellectual disability, and meaningful activities could prevent this negative progression. METHODS: This is a prospective cohort study in Spanish adults with intellectual disability during the COVID-19 pandemic. Quality of life, functional autonomy and functional independence were measured. The meaningful activities studied were structured-leisure, community self-management, and occupational and physical activities. RESULTS: Seventy-three participants were included in the study. Quality of life and functional autonomy significantly deteriorated during the COVID-19 pandemic (all p > .001). Greater participation in community self-management activities before COVID-19 was associated with less detriment to quality of life (ß = -.312; p = .008), while greater participation in occupational and physical activities was associated with less detriment to the performance of instrumental activities (ß = -.317; p = .016; and ß = -.285; p = .030, respectively). CONCLUSION: People with intellectual disability living in residential homes experienced a decrease in their quality of life and functional autonomy during the COVID-19 pandemic. Their involvement in community self-management activities and physical and occupational activities before the pandemic had preventive effects on the detriment to the quality of life and functional autonomy.

Effect of the environmental factor of coexistence on the physical condition of people with mild and moderate intellectual disabilities.

BACKGROUND: The main objective of this study was to compare the physical condition of people with intellectual disabilities living in residential homes (RH; restricted residential environment) versus independent homes (IH; family houses while performing paid work). The effect of gender on physical condition was also evaluated separately for each group. METHOD: Sixty individuals with mild to moderate intellectual disability, 30 living in RH and 30 living in IH, participated in this study. The RH and IH groups were homogeneous in terms of gender distribution (17 males and 13 females) and intellectual disability level. Body composition, postural balance, and static and dynamic force were considered as dependent variables. RESULTS: The IH group performed better in the postural balance and dynamic force tests compared to the RH group, but no significant differences between the groups were observed for any body composition or static force variable. Women in both groups tended to have better postural balance than men, while men presented higher dynamic force. CONCLUSIONS: The IH group presented a higher physical fitness compared to RH group. This result emphasises the need to increase the frequency and intensity of the physical activity sessions commonly programed for individuals living in RH.

Effect of a Combined Program of Strength and Dual Cognitive-Motor Tasks in Multiple Sclerosis Subjects.

This study investigated the effects of a 24-week combined training program (CTP) based on strength exercises and cognitive-motor tasks performed concurrently in participants with multiple sclerosis. A randomized, controlled intervention study was carried out. In total, 31 subjects with a confirmed diagnosis of multiple sclerosis (14 men and 17 women) were stratified and randomized into an intervention group (17 subjects) and a control group (14 subjects). The intervention group completed three weekly training sessions for 24 weeks, while the control group pursued their normal daily activities. In this program, cognitive-motor tasks were completed at once (dual tasking). A 3D photogrammetry connected to a selective attention system designed for dual tasking while walking was used. Ground reaction forces were measured using two force plates, one for sit-to-stand testing, while the other was used for static force measurement. Postural equilibrium was examined using a stabilometric plate based for Romberg test assessment. The 24-week training program for multiple sclerosis patients improved their static peak force by 11% (p < 0 .05), their rate of force development by 36% (p < 0.05), and their balance (p < 0.05). Performance in daily activities such as walking or sitting-to-standing improved significantly in multiple sclerosis participants. CTP training was effective in reducing the dual-task costs of step length (48%) and walking velocity (54%), as compared to a matched control group.

Dual-Task Cost of Discrimination Tasks During Gait in People With Multiple Sclerosis.

PURPOSE: The aim of the study was to assess dual-task cost to spatio-temporal gait parameters in people with multiple sclerosis and a matched control group. METHOD: The multiple sclerosis group was composed of 17 participants with a diagnosis of multiple sclerosis and an Expanded Disability Status Scale score of less than 6. A total of 17 healthy participants were allocated to the control group by stratification. Controls were matched on the basis of age, sex, sociocultural habits, and body structure. Dual-task cost was determined by within-group repeated-measures analysis of variance. Participants were instructed to ambulate under normal conditions and perform a discrimination and decision-making task concurrently. Then, between-group analysis of variance was used to assess differences in mean dual-task cost between groups and determine dual-task cost differential. Testing was performed using three-dimensional photogrammetry and an electronic walkway. RESULTS: Based on dual-task cost differential, gait cycle time increase (-5.8%) and gait speed decrease (6.3%) because of multiple sclerosis-induced impairment. CONCLUSIONS: During single- and dual-task conditions, gait speed was lower in multiple sclerosis participants, because of a shorter step length and increased swing time. Increased gait time might be the result of compensatory mechanisms adopted to maintain stability while walking specially during the double-support phases.

Components of attack response inhibition in fencing: Components of attack response inhibition in fencing.

Applying the Go/No-Go paradigm to fencing, we investigated the relationship between the moment at which the No-Go signal appeared after a movement had been initiated and the time required by fencers to suppress the motor execution of a step-lunge. Secondarily, we determined a time threshold from which movement inhibition results in an error. The No-Go stimulus was represented by a real attack movement. 18 elite fencers and a fencing master were included in the study. Four force plates measured the horizontal components of the fencer's and master's reaction forces, which were used to calculate the time components of the attack and the response inhibition process. Also, the velocity and displacement of the master's and fencer's respective centres of mass were estimated using inverse dynamics. In all cases, cognitive inhibition processes were completed after the onset of movement. Movement time was calculated using four time components (muscle activation, muscle deactivation, transition and braking time). The results obtained revealed that cognitive processes were not significantly affected by the timing of the appearance of the No-Go signal. In contrast, movement time and its time components tended to decrease when the time delay between the No-Go stimulus and the onset of the fencer's movement increased. In conclusion, any attempt to withhold an attack movement when it has already started leads to an error that increases the risk of being hit by the opponent, especially when attack is inhibited within 150 ms after the movement has started.

Evaluación estabilométrica en personas con discapacidad intelectual / No disponible

El objeto de este trabajo ha sido realizar una evaluación sobre el control postural en personas con diferentes grados de discapacidad intelectual que facilite el diseño programas generales de actuación orientados a la mejora de las capacidades físicas y cognitivas. Han participado 45 personas de la Fundación Purísima Concepción de Granada con diferente nivel de discapacidad intelectual, a los que se le aplicaron las cuatro situaciones que describe el test de Romberg más una situación donde se pretende determinar el efecto de una tarea cognitiva sobre el control postural. Para el registro de las variables estabilométricas se ha utilizado una plataforma de fuerza Dinascan/IBV y una alfombrilla de gomaespuma sobre la superficie. Los resultados indican que las variables estabilométricas más sensibles a los cambios producidos por la manipulación de los estímulos vestibulares, visuales y somatosensoriales son: el desplazamiento total del CP y el área descrita por el CP en su recorrido por la base de sustentación. Han sido escasos los efectos producidos por la actividad dual. No se han constatado valores de significación estadística cuando se correlaciona el nivel de discapacidad intelectual con las diferentes variables estabilométricas registradas, lo que podría estar relacionado con la alta variabilidad registrada entre los participantes. Como conclusión general, se considera útil el análisis de las pruebas estabilométricas para la realización de un diseño individualizado de programas de rehabilitación e intervención deportiva en personas con discapacidad intelectual y de esta forma ayudar a la inclusión de personas con discapacidad intelectual

The aim of this project has been the realization of an evaluation about postural control in people with different degrees of intellectual disability which facilitates the design of general action programmes oriented to the improvement of physical and cognitive abilities. 45 people with different degrees of intellectual disability from Purísima Concepción de Granada Foundation have participated on it, who were applied the four situations that Romberg's test describes and also a situation where it is expected to determine the effect of a cognitive task on postural control. For the stabilometric variables register it has been used a Dinascan/IBV strength platform and a foam mat on the surface. The results indicate that the most sensitive stabilometric variables to the changes produced by the handling of vestibular, visual and somatosensory stimuli are: the CP total displacement and the area described by the CP on its walk through the sustenance base. The effects produced by dual activity have been scarce. It has not been confirmed meaning statistics values when it is correlated the level of intellectual disability with the different registered stabilometric variables, which could be related to the high variability registered among the participants. As a general conclusion, the analysis of stabilometric tests is considered useful for the realization of a personalized design of rehabilitation and sports intervention programme in people with intellectual disability and in this way it will help the inclusion of people with intellectual disability

Effect of dual-attention task on attack and defensive actions in fencing.

The objectives of this study were to investigate the effect that the presence of two stimuli that require two different responses (dual-attention) has both, on offensive reaction-response time to a light stimulus, and on defensive response time when the stimulus is a real fencing attack. Twenty-five elite fencers and a fencing master were included in the study. The equipment included four force plates adapted to a scaffold that served as a fencing piste. Two force plates were placed, at the start position, under the fencer's feet and another two plates were placed under the master's feet. The results demonstrate that choice reaction time to visual stimuli increases in dual-task conditions with respect to simple reaction time, whereas the mean horizontal force tends to decrease in dual-task. However, when the stimulus was an opponent's movement, dual-task conditions did not have any effect on the time required to initiate a defensive action. The changes in reaction time when real movements were used as stimuli challenge the validity of the reaction time to visual stimuli paradigm as a predictor of performance in fencing. Also, the results obtained demonstrate that perceptual and attentional processes play a major role in fencer performance in real competition.

Time Required to Initiate a Defensive Reaction to Direct and Feint Attacks in Fencing.

The two-fold purpose of this study was to analyze the time required by a fencer to initiate a defensive action in response to a direct attack, which involves identifying when the defending fencer detects the just-noticeable difference, and, secondly, to assess the effect that an attacker's rapid armed hand movement (feint attack) has on the time required to initiate a defensive move. Twenty-four elite fencers and a fencing master were included in the study. Four adapted force plates were installed on a scaffold used as a fencing piste. A 3D video analysis system recorded the location of 2 markers installed on the fencing master's shoulder and sword. The results confirm that the defending fencer has a mean movement time of 0.353 ± 0.028 s to perform the defensive action, which provides an advantage over the attacking fencer. The velocity of movement in the peripheral visual field has no influence on the time required by elite fencers to initiate a defensive action. This confirms the crucial role that response inhibition processes play when nonrelevant actions are perceived. Kinematic analysis of markers suggests that the eye movements of elite fencers are not the only source of information used while observing an attack.

Effect of dual-task-induced uncertainty on gait biomechanics in patients with multiple sclerosis with 2-6.5 EDSS grade.

The goal of this study was to assess the effect that uncertainty induced by dual task conditions has on reaction-response time parameters and gait patterns of patients with multiple sclerosis (MS) with a 2-6.5 EDSS grade. The study involved eleven patients - nine women and two men - diagnosed with multiple sclerosis (age, 48±10years; height, 1.65±0.1m; weight, 72±22kg) with capacity to walk five meters without any aid or assistance. We employed an intra-group repeated measures design. Each participant was asked to walk with and without task-related uncertainty. Reaction-response and gait cycle times, as well as center of mass (CM) dynamics were measured using three force plates synchronized with a video camera through an electronic device that also controlled the system of uncertainty. The results obtained reveal that uncertainty induced by dual tasking is related to a reduction in the mean stride length and mean displacement and horizontal velocity of the CM in patients with MS. The values obtained for CM parameters indicate that uncertainty affects balance, as compared to no-uncertainty situations. These results confirm the necessity of including controlled dual-task-induced uncertainty in physical training programs for MS patients.

Effect of defence response time during lunge in foil fencing.

The aim of this study was to analyse the effect of stimulus change timing on reaction response time parameters, horizontal velocity of the centre of mass (CM) and precision during offensive actions in fencing. Twelve fencers from the Spanish National Foil Team were included in the study. Two 500 Hz force plates were used to register the horizontal component of the reaction force while a 3D video camera set at 250 Hz recorded the spatial position of 11 body markers and a projector connected to a programmed stopwatch projected a moving target (stimulus) on a screen. When the circle (target) appeared in the centre of the plastron, fencers had to execute a step-forward-lunge as fast as possible, trying to touch the circle with the tip of the foil. During the lunge, the position of the target could randomly shift or not to three different positions. The stimulus change was performed randomly at four different times with a progressive delay. The results show that target changes did not have any effect when they occurred at the beginning of the movement sequence. However, when the target change was delayed, reaction and movement times increased and the technical execution of the lunge changed, leading to more errors.

Effect of uncertainty during the lunge in fencing.

The aim of this study is to determine the effect that uncertainty, in relation to the probability of error, exerts on the reaction response and speed during the lunge in fencing. The participants were 18 regional-level fencers with over five years' experience. Force platforms under the feet recorded the horizontal components of the reaction forces, from which the kinematic parameters of the center of mass were calculated. An electronic system to present stimuli, controlled by a programmable clock, projected a target onto a screen that represented a plastron. In situations without uncertainty, the fencers had to lunge as swiftly as possible when a circle (the target) appeared in the center of the plastron, trying to touch the center of the circle with the tip of the sword. In situations with uncertainty, the fencers had the same target as in the previous situation but they received the information that they had to change the lunge into a defensive move if the target disappeared from the plastron during the action. The results indicate that the reaction time and the movement time increased with uncertainty. Although there were no differences for the horizontal velocity of the center of mass at the end of the acceleration phase, the mean horizontal velocity of the lunge was reduced by the effect of the uncertainty. Prior knowledge of the opponent´s possible action implies a reduction in uncertainty, reducing movement time as well as meaning faster execution, thereby increasing the success of the lunge in fencing. Key PointsReaction time (RT) and the movement time (MT) increase when doubts arise about being able to reach the target as planned during the lunge.The horizontal velocity of the lunge decreases by the effect of uncertainty due to the possibility that the events might not occur as planned.These results highlight the importance that tactical intent has in fencing for successfully predicting the defensive movements of the opponent during the attack.

Efecto de la restricción segmentaria en los test de salto vertical CMJ / Effect of segmental restriction in the vertical jump test CMJ

En esta investigación se han pretendido tres objetivos: a) evaluarla contribución segmentaria en la altura alcanzada por el Centro de Masas (CM) en el salto vertical contramovimiento, b) proponer ecuaciones que nos permitan predecir la altura del salto a partir del protocolo propuesto en el test de Bosco CMJ y c) Investigar los efectos de diferentes métodos para el cálculo de la altura del salto vertical. Han participado 29 deportistas con experiencia en el salto vertical. Las fuerzas de reacción se obtuvieron a través de una plataforma de fuerza Dinascam/IBV a una frecuencia de 500 Hz, sincronizada temporalmente a una cámara de alta velocidad que registraba el plano sagital de los saltos realizados sobre la plataforma. Los sujetos realizaron dos tipos de saltos verticales máximos: con acción de brazos (CMJ+b) y usando el protocolo del test Bosco (CMJ). Los registros de las componentes rectangulares de la velocidad y la posición del CM, se determinaron mediante integración, a partir de las respectivas componentes de la fuerza de reacción. Los resultados han puesto de manifiesto que con acción de brazos, la altura alcanzada por el CM se incrementa un 12%.El 39% de este incremento se debió a la posición del CM en el despegue y el 61% restante al desplazamiento vertical del CM. El desplazamiento vertical del CM se debió al tiempo de impulso y no al incremento de la fuerza media. Cuando se incrementa el desplazamiento vertical del CM para los saltos sin acción de brazos, también se incrementa para los saltos realizados con acción de brazos (r =0.79; p<0.001). No se han encontrado diferencias entre los dos sistemas de registro para los saltos CMJ+ b, mientras que cuando se utiliza el "test de Bosco" (CMJ) han existido claras diferencias (p<0.001) (AU)

This research had three main goals: a) to assess the segmental contribution to the reached height by the center of mass (CM) during countermovement vertical jump, b) to propose equations that allow us to predict the height of the jump from the proposed protocol Bosco in the CMJ test and c) to investigate the effects of different methods to calculate vertical jump height. Twenty-nine athletes with experience in vertical jump took part on the study. Ground reaction forces were obtained from a Dinascam/IBV force platform at a sampling rate of 500 Hz, a time-synchronized to a high speed camera that recorded the sagittal plane of the jumps performed on the platform. The subjects performed maximum vertical jumps with arm action (CMJ + b) and using the test protocol Bosco (CMJ). The records of the rectangular components of the velocity and position of the CM were determined by integration, from the respective components of the reaction force. The results have shown that action of the arms, the height reached by the CM is increased by 12%. This increased was 39% due to the position of the CM at takeoff and 61% because of the vertical displacement of CM. The increase of the vertical displacement was due to the pulse time and the increase in average strength. When the vertical displacement of CM for action jumps without arms was increased, it was also increased for the action jumps performed with arms (r =0.79, p <0.001). No differences were found between the registration systems for jumps CMJ + b, whereas when there was used "test of Bosco" (CMJ) there were found clear differences (p <0.001) (AU)