Search results for "hand"
showing 10 items of 1364 documents
Effects of combined hand-arm vibration and cold on skin temperature
1989
Under laboratory conditions 14 healthy male subjects were exposed to hand-arm vibration (ahzw = 6.3 m/s2) at different air temperatures (5 degrees, 12 degrees, 18 degrees and 25 degrees C). Static load (grip force 15 N, push force 40 N) was kept constant. Finger tip temperature as an indirect criterion of the peripheral blood circulation was measured. As expected, low air temperatures (5 degrees, 12 degrees and 18 degrees C) cause a strong decrease of skin temperature. Under additional stress of vibration connected with static load, a further decrease of the mean skin temperature was noted. At this, static load proved to have a predominant influence on the acute diminution of skin temperatu…
Handgrip strength: a predictive indicator of upper body maximal strength?
2013
In the last few years, Handgrip strength has been widely recognized as a relevant indicator of physical function, nutritional status and quality of life in a clinical population. The validity of this indicator has been reported in many experimental and epidemiological investigations, showing a significant association of this value with several physiological and not physiological parameters. Bone health, functional capacity, nutritional status as well as postoperative complications, increased length of hospitalization and higher rehospitalisation rate are all elements found to be strongly associated with an acceptable or with an impaired grip strength. These outcomes, as well as the possibil…
Object-Guided Spatial Selection in Touch Without Concurrent Changes in the Perceived Location of the Hands
2012
In an endogenous cueing paradigm with central visual cues, observers made speeded responses to tactile targets at the hands, which were either close together or far apart, and holding either two separate objects or one common object between them. When the hands were far apart, the response time costs associated with attending to the wrong hand were reduced when attention had to be shifted along one object jointly held by both hands compared to when it was shifted over the same distance but across separate objects. Similar reductions in attentional costs were observed when the hands were placed closer together, suggesting that processing at one hand is less prioritized over that at another …
Eye-Hand Coordination in Rhythmical Pointing
2009
International audience; The authors investigated the relation between hand kinematics and eye movements in 2 variants of a rhythmical Fitts's task in which eye movements were necessary or not necessary. P. M. Fitts's (1954) law held in both conditions with similar slope and marginal differences in hand-kinematic patterns and movement continuity. Movement continuity and eye-hand synchronization were more directly related to movement time than to task index of difficulty. When movement time was decreased to fewer than 350 ms, eye-hand synchronization switched from continuous monitoring to intermittent control. The 1:1 frequency ratio with stable pi/6 relative phase changed for 1:3 and 1:5 fre…
Changes of electrically elicited reflexes in hand and forearm muscles in man.
1987
Cutaneo-muscular reflexes with short and long latency excitatory phases following digital nerve stimulation were observed in the first dorsal interosseus muscle of the hand in healthy subjects. The short latency reflex was obtained also with the H-reflex method in the flexor carpi radialis muscle, stimulating the median nerve, with a mean latency (+/- SE) of 15.4 +/- 0.5 ms. The height of the subject correlated with the H-reflex latency. The amplitudes of maximal M-response and maximal H-reflex were higher in athletes than in normals. During weak voluntary contraction of the muscle studied the 50% H-reflex amplitude increased and during passive stretching of wrist flexors the resting amplit…
Long-Term Determinants of Muscle Strength Decline: Prospective Evidence from the 22-Year Mini-Finland Follow-Up Survey
2012
Objectives: To examine long-term changes in handgrip strength and the factors predicting handgrip strength decline. Design: Longitudinal cohort study with 22 years of follow-up. Setting: Population-based Mini-Finland Health Examination Survey in Finland. Participants: Nine hundred sixty-three men and women aged 30 to 73 at baseline. Measurements: Handgrip strength was measured using a handheld dynamometer at baseline and follow-up. Information on potential risk factors, namely lifestyle and chronic conditions, and their changes throughout the follow-up were based on health interviews. Results: Based on linear mixed-effect models, midlife physically strenuous work, excess body weight, smokin…
Task-Modulated Corticocortical Synchrony in the Cognitive-Motor Network Supporting Handwriting
2019
Abstract Both motor and cognitive aspects of behavior depend on dynamic, accurately timed neural processes in large-scale brain networks. Here, we studied synchronous interplay between cortical regions during production of cognitive-motor sequences in humans. Specifically, variants of handwriting that differed in motor variability, linguistic content, and memorization of movement cues were contrasted to unveil functional sensitivity of corticocortical connections. Data-driven magnetoencephalography mapping (n = 10) uncovered modulation of mostly left-hemispheric corticocortical interactions, as quantified by relative changes in phase synchronization. At low frequencies (~2–13 Hz), enhanced …
Does order and timing in performance of imagined and actual movements affect the motor imagery process? The duration of walking and writing task.
2002
The purpose of the present study was to investigate the effects on the duration of imagined movements of changes in timing and order of performance of actual and imagined movement. Two groups of subjects had to actually execute and imagine a walking and a writing task. The first group first executed 10 trials of the actual movements (block A) and then imagined the same movements at different intervals: immediately after actual movements (block I-1) and after 25 min (I-2), 50 min (I-3) and 75 min (I-4) interval. The second group first imagined and then actually executed the tasks. The duration of actual and imagined movements, recorded by means of an electronic stopwatch operated by the subj…
Intermittent cooling during judo training in a warm/humid environment reduces autonomic and hormonal impact
2018
Carballeira, E, Morales, J, Fukuda, DH, Granada, ML, Carratalá-Deval, V, López Díaz de Durana, A, and Stout, JR. Intermittent cooling during Judo training in a warm/humid environment reduces autonomic and hormonal impact. J Strength Cond Res 33(8): 2241-2250, 2019-The purpose of this study was to identify the effects of superficial cooling on physiological responses while training in a warm, humid environment during an international Judo training camp. Sixteen judokas (8 women and 8 men) participated in the experiment. Four high-level women and 4 men were randomly assigned to wear a cooling vest (vest group [VG]) during the recovery periods within a training session (i.e., 8 bouts of 5-minu…
Influence of stimulus color on the control of reaching-grasping movements.
2001
This kinematic study aimed to determine whether color is a stimulus property involved in the control of reaching-grasping movements. Subjects reached and grasped a target-object, located either on the right or on the left of the subject's midline. A distractor, placed along the subject's midline, could be randomly presented. The colors, i.e., both chromaticity (red and green stimuli were presented) and lightness, of the target and distractor were varied in experiment 1. Only stimulus lightness and only stimulus chromaticity were varied in experiments 2 and 3, respectively. In experiment 4 subjects matched with their thumb and index finger the size of the target-stimuli presented in experime…