Differences related to aging in sensorimotor knowledge: Investigation of perceptual strength and body object interaction.

Embodied approach postulates that knowledge and conceptual representations are grounded in action and perception. In order to investigate the involvement of sensorimotor information in conceptual and cognitive processing, researchers have collected various norms in young adults. For instance, the perceptual strength (PS) assesses perceptual experience (i.e. visual, auditory, haptic, gustatory, olfactory) associated with a concept and the body-object-interaction (BOI) assesses the ease with which a human body can interact with the referent of a word. The importance of both BOI and PS in the multimodal composition of word meaning is today well recognized. However, given the sensorimotor development of the individual from childhood to later life, it is likely that different age periods are associated with different perceptual experience and capacity to interact with objects. The purpose of this research is to investigate exploratory the effect of age on PS and BOI by comparing the evaluation of 270 French language words by young adults and healthy older people. The results showed that older adults presented similar or even higher PS for some modalities (e.g. gustatory and olfactory) and in particular for certain categories of words, while the BOI decreases. In addition to the importance of adjusting the verbal stimuli used in aging studies when dealing with multimodal representations, our results will lead us to discuss the evolution of sensorimotor representations with age.

Test of Special Relativity Using a Fiber Network of Optical Clocks.

Phase compensated optical fiber links enable high accuracy atomic clocks separated by thousands of kilometers to be compared with unprecedented statistical resolution. By searching for a daily variation of the frequency difference between four strontium optical lattice clocks in different locations throughout Europe connected by such links, we improve upon previous tests of time dilation predicted by special relativity. We obtain a constraint on the Robertson-Mansouri-Sexl parameter |α|≲1.1×10^{-8}, quantifying a violation of time dilation, thus improving by a factor of around 2 the best known constraint obtained with Ives-Stilwell type experiments, and by 2 orders of magnitude the best constraint obtained by comparing atomic clocks. This work is the first of a new generation of tests of fundamental physics using optical clocks and fiber links. As clocks improve, and as fiber links are routinely operated, we expect that the tests initiated in this Letter will improve by orders of magnitude in the near future.

Improved skeletal muscle performance after individualized exercise training in patients with chronic obstructive pulmonary disease.

BACKGROUND: In addition to the respiratory limitation in patients with chronic obstructive pulmonary disease (COPD), skeletal muscle abnormalities may occur and contribute to the exercise intolerance. This study assessed the ability of the skeletal muscle of patients with COPD to adapt to individualized exercise training at the gas exchange threshold (GET) METHODS: Fourteen patients (8 in a training group and 6 controls) performed the following exercise tests before and after a 3-week training period: an incremental exercise test, maximal voluntary contraction of the quadriceps, and three endurance tests consisting of dynamic contractions of the quadriceps until exhaustion. These endurance tests, characterized by three different power outputs, were used to determine muscle limit times and critical power. RESULTS: The results showed that training increased exercise tolerance (+11% for symptom limited peak oxygen consumption (VO2 sl], P < 0.05), maximum voluntary contraction (+8%, P < 0.05), limit times (from +45% to +161%, P < 0.05) and critical power (+39%, P < 0.05). CONCLUSIONS: These findings indicate greater muscle strength and endurance after training in COPD patients and suggest better muscular recruitment and improved oxidative capacity in the exercising muscles. The sharp differences in the magnitude of VO2 sl and limit times suggest that the kinetics of peripheral and central changes in response to training are different. In conclusion, peripheral muscle performance can be increased rapidly in response to an individualized training program at the GET in COPD patients.

Comparison of two training programmes in chronic airway limitation patients: standardized versus individualized protocols.

This study tested the effect of two methods of training, one individualized at the heart rate corresponding to the gas exchange threshold (GET) and the other at the heart rate corresponding to 50% of maximal heart rate reserve, on maximal and submaximal cardiorespiratory response in 24 patients with chronic airway limitation (CAL). The patients were randomly assigned to either the individualized training group (IT; n = 12) or the standardized training group (ST; n = 12). The training programme consisted of 4 weeks of stationary bicycle exercise, 5 days.week-1. Before reconditioning began, the target level based on heart rate was not significantly different between groups (109 +/- 4 versus 110 +/- 3 beats.min-1, in IT and ST, respectively). Post-training, a significant increase in symptom-limited oxygen uptake (V'O2.sl) and maximal O2 pulse was found in IT, whereas ST exhibited no significant change. In each group, GET was statistically increased in much the same way as V'O2,sl, with a higher increase in IT (p < 0.01) than ST (p < 0.05). Nevertheless, IT exhibited a concomitant and gradual decrease in minute ventilation (V'E), carbon dioxide production (V'CO2), and venous lactate concentration ([La]), whereas ST presented no significant change in these parameters (intergroup p < 0.01). Breathing pattern was also altered after IT, at the same metabolic level and at the same ventilation level (intergroup p < 0.05). Cardiac responses were modified in the two groups. At the same metabolic level, a significantly lower cardiac frequency was found both for IT and ST (intragroup p < 0.05 after training). In contrast, the increase in O2 pulse was only significantly higher in It after training. These data show the greater efficiency of an individualized training protocol based on determination of gas exchange threshold as compared to a standardized protocol, in improving exercise performance, when applied to a patient group. Despite an apparently similar target training level, the individualized method clearly optimized the physiological training effects in patients with chronic airway limitation and, more particularly, decreased their ventilatory requirement.

[Value of individualized rehabilitation at the ventilatory threshold level in moderately severe chronic obstructive pulmonary disease]. / Intérêt du réentraînement à l'effort individualisé, au niveau du seuil ventilatoire, au cours de la bronchopneumopathie chronique obstructive de sévérité modérée.

In order to study the efficiency of individual training programs at the ventilatory threshold level, twenty COPD patients were randomized into two groups and studied over a two-month period. At the start, during, and at the end of the study all subjects performed incremental exercise tests. The trained group (59.60 SEM +/- 2.75 years) walked four times a week at the heart rate corresponding to the metabolic level of ventilatory threshold. The other group served as controls (58.2 +/- 1.80 years). A marked increase in the symptom-limited oxygen consumption (+/- 25%) (p < 0.01), the maximal ventilation (+20%) (p < 0.01), and the ventilatory threshold (+19%) (p < 0.05) was found in the trained group. No modification was recorded in the control group. The ventilatory pattern at submaximal intensities expressed in percentage of the initial oxygen consumption showed significant differences between groups, the trained-group ventilation decreased at 50% and 75% VO2 sl (p < 0.05). The breathing frequency also decreased at 50% and 75% VO2 sl (p > 0.05). Moreover, we observed an increase in the oxygen pulse at 50% VO2 sl (p < 0.05). In conclusion, this study demonstrates that individualized training at the ventilatory threshold level increases exercise tolerance and produces better ventilatory comfort in COPD patients.