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Weiyun Chen, Inez Rovegno, John Todorovich and Matt Babiarz

The purpose of this study was to describe third grade children’s movement responses to dribbling tasks taught by four accomplished teachers and how children’s dribbling varied with changes in task constraints. Children in four intact classes were videotaped during three dribbling lessons as part of their physical education program. Videotapes were analyzed to provide descriptions of children’s movement responses. Typically, when children dribbled while walking or jogging they controlled the ball, pushed with finger pads, and looked at the ball. When dribbling tasks were more difficult, in general, there was less ball control and more slapping with palms (less mature patterns) while at the same time more instances of children lifting their heads to look up (a more mature pattern). Task constraints had differential impacts on different dribbling elements. One implication is that teachers need to consider this differential impact in designing practice conditions and in selecting assessment tasks.

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Blanka Hejduková, Nasser Hosseini, Bo Johnels, Pall E. Ingvarsson, Goran Steg and Torsten Olsson

During transport of an object using the precision grip with thumb and index finger, a modulation of the grip force is needed in response to the forces evoked by the movement. We measured the grip force (GF) and the load force (LF) in 10 healthy participants moving a 640-g object forward and upward. The task was repeated with various speeds. There were considerable changes with speed of the LF trajectory but not of the GF trajectory. A loss of synergy between GF and LF appeared in fast lifts. This is in contrast to the close coupling between load force and grip force repeatedly demonstrated during simple lifts. We suggest that (a) speed should be considered as an input parameter for movement planning, and (b) regulation of GF and of LF are independent under certain conditions. We discuss whether the grip-load force synergy should be considered a special case rather than a more general principle.

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Claudia Voelcker-Rehage and Ben Godde

We examined the effect of high frequency tactile stimulation (tHFS) on tactile and motor performance as well as tactile-motor interactions. Seventeen right-handed participants (66–78 years) underwent a pretest (tactile frequency and spatial discrimination task, manual dexterity test, and precision grip task) with their left hand, received 30 min of tHFS on the tips of their left index finger and thumb, and performed a posttest (control group: no stimulation). Results indicated an improvement in frequency and spatial discrimination in the experimental but not the control group. In the precision grip task, however, training effects as found for the control group seem to be blocked in the experimental group. For the manual dexterity task no effect was found. Our data indicate that tHFS positively influences tactile performance. Assuming tHFS-induced plastic reorganization in somatosensory cortex our results give further evidence to the notion of an interrelation between sensory and motor performance.

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Justin W.L. Keogh, Steve Morrison and Rod Barrett

The current study investigated the effect of 2 different types of unilateral resistance training on the postural tremor output of 19 neurologically healthy men age 70–80 yr. The strength- (n = 7) and coordination-training (n = 7) groups trained twice a week for 6 wk, performing dumbbell biceps curls, wrist flexions, and wrist extensions, while the control group (n = 5) maintained their normal activities. Changes in index-finger tremor (RMS amplitude, peak, and proportional power) and upper limb muscle coactivation were assessed during 4 postural conditions that were performed separately with the trained and untrained limbs. The 2 training groups experienced significantly greater reductions in mean RMS tremor amplitude, peak, and proportional tremor power 8–12 Hz and upper limb muscle coactivation, as well as greater increases in strength, than the control group. These results further demonstrate the benefits of resistance training for improving function in older adults.

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Eric G. James

The HKB model and its variants characterize bimanual coordination with fixedpoint dynamics and predict stationarity of the mean and variance of relative phase in stable coordinative states. In the current study, participants performed in-phase and antiphase coordination modes in rhythmic bimanual finger and elbow flexionextension tasks. The results of runs tests revealed that discrete relative phase was nonstationary in 49.25%, 50.25%, and 54% of time-series in the 10, 20, and 30 box runs tests, respectively. In all individual Task conditions >38% of time-series were nonstationary. These findings contradicted model predictions that the mean and variance of relative phase are stationary in bimanual coordination and distinguish the concept of dynamical stability from statistical stationarity. The findings indicated that relative phase was not attracted to a stationary fixed-point and that fluctuations in relative phase are not Gaussian white noise as in existing models of bimanual coordination.

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Bouwien C. M. Smits-Engelsman, Stephan P. Swinnen and Jacques Duysens

It has been shown that crossing the midline affects the performance of fine motor skills but the underlying mechanisms are not well understood. This issue is particularly important with respect to the development of motor activities such as writing or pointing in children. Forty-eight right-handed children performed goal-directed movements toward targets positioned either at the midline, or in the left (contralateral side), or right (ipsilateral) hemispace. Findings revealed that movements were more accurate in ipsilateral than in contralateral space and their overall accuracy increased by 42% between 6 and 10 years of age. Differences in movement time among hemispaces depended on the joints predominantly involved in producing the movements (wrist versus fingers). Lower accuracy of movements in contralateral workspace is also present when participants do not have to cross the midline but only move within this workspace. In motor proficient children, no developmental trends were found for these hemispace effects.

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Werner W.K. Hoeger, David R. Hopkins, Sherman Button and Troy A. Palmer

This study compared the proposed modified sit and reach test (MSR) and the commonly administered sit and reach test (SR) to determine if the MSR can administratively control possible limb-length biases. Subjects (N=258) were administered two trials of each test. The MSR test incorporates a finger-to-box distance (FBD) to account for proportional differences between legs and arms. Individuals with high FBD measurements demonstrated a poorer performance on the SR test. An analysis of the subjects failing to meet the Physical Best standard (25 cm) indicated a higher probability of failure for those with larger FBD scores. The subjects were subsequently separated into three groups: high, medium, and low FBD. There were no significant difference among the groups on MSR performance but a significant difference was found on SR performance. The MSR test appears to eliminate the concern of disproportionate limb-length bias expressed by many practitioners.

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Marco Rathschlag and Daniel Memmert

The present study examined the relationship between self-generated emotions and physical performance. All participants took part in five emotion induction conditions (happiness, anger, anxiety, sadness, and an emotion-neutral state) and we investigated their influence on the force of the finger musculature (Experiment 1), the jump height of a counter-movement jump (Experiment 2), and the velocity of a thrown ball (Experiment 3). All experiments showed that participants could produce significantly better physical performances when recalling anger or happiness emotions in contrast to the emotion-neutral state. Experiments 1 and 2 also revealed that physical performance in the anger and the happiness conditions was significantly enhanced compared with the anxiety and the sadness conditions. Results are discussed in relation to the Lazarus (1991a, 2000a) cognitive-motivational-relational (CMR) theory framework.

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Michael S. Ferrara and William E. Buckley

The Athletes With Disabilities Injury Registry (ADIR) was designed to collect and analyze injury data from 1990 to 1992. Three hundred nineteen athletes from different disability organizations participated, and 128 reportable injuries were recorded. The injury rate during the study period was 9.45/1,000 athlete-exposures. Overall, 52% of the reported injuries were minor (0–7 days missed), 29% were moderate (8–21 days missed), and 19% were major (22 or more days missed). The shoulder and forearm/wrist accounted for the most days lost, followed by the hand/fingers and the upper arm/elbow. Musculoskeletal injuries accounted for 81 % of the reported injuries, and illness or disability-related problems accounted for 19%. Fifteen percent of the moderate and major injuries were not medically evaluated. This raises questions about access to medical care and the appropriate recognition of an injury. Injury prevention programs should focus on reducing the number of major injuries and educating athletes and coaches about appropriate medical referrals.

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Maria W.G. Nijhuis-Van der Sanden, Edwin H.F. Van Asseldonk, Paul A.T.M. Eling and Gerard P. Van Galen

This study examined the relationship between decreased speed-accuracy tradeoff and increased neuromotor noise in girls with Turner Syndrome (TS). Fifteen girls with TS and 15 age-matched controls performed isometric force contractions with both index fingers separately at 5 force levels, based on their maximum voluntary contraction. The results revealed that (a) groups did not differ in speed-accuracy tradeoff or neuromotor noise, (b) output-variability increased linearly with force level, (c) signal-to-noise ratio changed according to an inverted U-shaped function, (d) broadening in the frequency profile is highest at the lower force levels, (e) with increasing force level, the power peak in the 0–4 Hz domain dominates, (f) frequency profile broadens more in the dominant hand. These findings suggest that, in girls with TS, motor performance is not diminished in an isometric force task, that motor recruitment is intact, and that neuromotor noise is not increased. The findings are discussed with respect to motor control and neuromotor noise.