Search Results

You are looking at 141 - 150 of 906 items for :

Clear All
Restricted access

Oliver Gonzalo-Skok, Julio Tous-Fajardo, Carlos Valero-Campo, César Berzosa, Ana Vanessa Bataller, José Luis Arjol-Serrano, Gerard Moras and Alberto Mendez-Villanueva


To analyze the effects of 2 different eccentric-overload training (EOT) programs, using a rotational conical pulley, on functional performance in team-sport players. A traditional movement paradigm (ie, squat) including several sets of 1 bilateral and vertical movement was compared with a novel paradigm including a different exercise in each set of unilateral and multi-directional movements.


Forty-eight amateur or semiprofessional team-sport players were randomly assigned to an EOT program including either the same bilateral vertical (CBV, n = 24) movement (squat) or different unilateral multidirectional (VUMD, n = 24) movements. Training programs consisted of 6 sets of 1 exercise (CBV) or 1 set of 6 exercises (VUMD) × 6–10 repetitions with 3 min of passive recovery between sets and exercises, biweekly for 8 wk. Functional-performance assessment included several change-of-direction (COD) tests, a 25-m linear-sprint test, unilateral multidirectional jumping tests (ie, lateral, horizontal, and vertical), and a bilateral vertical-jump test.


Within-group analysis showed substantial improvements in all tests in both groups, with VUMD showing more robust adaptations in pooled COD tests and lateral/horizontal jumping, whereas the opposite occurred in CBV respecting linear sprinting and vertical jumping. Between-groups analyses showed substantially better results in lateral jumps (ES = 0.21), left-leg horizontal jump (ES = 0.35), and 10-m COD with right leg (ES = 0.42) in VUMD than in CBV. In contrast, left-leg countermovement jump (ES = 0.26) was possibly better in CBV than in VUMD.


Eight weeks of EOT induced substantial improvements in functional-performance tests, although the force-vector application may play a key role to develop different and specific functional adaptations.

Restricted access

Arend W. A. Van Gemmert and Hans-Leo Teulings

The term graphonomics refers to the scientific and technological effort involved in identifying relationships between the planning and generation of handwriting and drawing movements, the resulting spatial traces of writing and drawing instruments (either conventional or electronic), and the dynamic features of these traces (International Graphonomics Society, 1987). Since the term graphonomics was coined in 1982, the multidisciplinary nature of graphonomic research has attracted scientists in several fundamental and applied areas, including motor control, motor learning, motor development, movement disorders, neuropsychology, biophysics, forensic science, computer science, cognitive science, artificial intelligence, among others. The many different research areas that are represented at the biennial conferences of the International Graphonomic Society (IGS) are exemplified by the variety of research papers published in special issues and books resulting from these conferences (cf. Meulenbroek & Van Gemmert, 2003; Simner & Girouard, 2000; Van Galen & Morasso, 1998; Simner, Leedham, & Thomassen, 1996; Faure, Keuss, Lorette, & Vinter, 1994; Simner, Hulstijn, & Girouard, 1994; Plamondon, 1993; Van Galen & Stelmach, 1993; Van Galen, Thomassen, & Wing, 1991; Wann, Wing, & Søvik, 1991; Plamondon & Leedham, 1990; Plamondon, Suen, & Simner, 1989; Kao, Van Galen, & Hoosain, 1986; Thomassen, Keuss, Van Galen, & Grootveld, 1983). Starting at the 10th IGS conference in Nijmegen, 2001, the influence of multidisciplinary collaborations and technical advancements expanded the scope of paradigms of researchers interested in graphonomics (e.g., finger control, isometric force control, brain imaging). This expansion of paradigms and the multidisciplinary nature of graphonomic research was pushed further into the center of fine motor control at the 11th IGS conference held in Scottsdale, 2003. This special issue of Motor Control, containing papers from this conference, exemplifies this progress.

Restricted access

Dana Maslovat, Shannon S.D. Bredin, Romeo Chua and Ian M. Franks

A major component of a dynamical paradigm involves a “scanning” procedure in an attempt to determine an individual’s intrinsic coordination tendencies before learning, as well as subsequent changes in the coordination landscape after practice. The purpose of the present study was to evaluate two methods of the scanning procedure. Scans were performed before and after 75 trials of a 90° bimanual-coordination pattern and were compared with early and late acquisition trials. Four groups of participants performed scanning and acquisition trials using a combination of either concurrent visual feedback in the form of Lissajous figures, paced by an auditory metronome, or visual metronomes in the form of flashing stimuli. Analyses revealed that all groups improved performance of the 90° pattern with practice. As predicted by the theory of practice specificity, scanning via the same method as acquisition appears to be valid. Scanning via Lissajous figures when the acquisition procedure was flashing squares was also found to be valid, but not the opposite condition. Reasons for this unidirectional transfer are given with these results suggesting that the sensitivity of a given scanning method might be influenced by the method of acquiring the coordination pattern.

Restricted access

Stephanie M. Mazerolle, Thomas G. Bowman and Jessica L. Barrett

The commissioners of the Commission on Accreditation of Athletic Training Education (CAATE) and the Board of Directors of the National Athletic Trainers’ Association (NATA) have acted to move the professional degree in athletic training from a bachelor’s degree to a graduate degree. The decision was largely based upon growth of the profession and aligning with the face of healthcare education. Therefore, we wanted to understand the perceived benefits of the graduate model. Using a qualitative paradigm, we electronically interviewed 29 students and faculty members (13 athletic training faculty and program directors, 16 students) currently in Professional Masters Athletic Training Programs (PM ATP). These represented 13 of the 29 (45%) CAATE-accredited PM ATPs. Five themes emerged from the data: (1) engagement and time spent in clinical education allows students to prepare for their roles as athletic trainers, (2) faculty stress the importance of interprofessional education, (3) expecting prior foundational knowledge allows focused education training at the graduate level, (4) increased professional commitment to stay in athletic training rather than use the training/education as a stepping-stone to other career paths, and (5) higher student maturity facilitates deeper learning. Based on these results, the perceived benefits of the PM ATP model are multifactorial.

Restricted access

Cyril Burdet and Patrice Rougier

To question the relation between uni- and bipedal postural skills, 21 subjects were required to stand on a force platform through uni- and bipedal conditions. These two protocols are commonly used paradigms to assess the balance capacities of healthy and disabled patients. The recorded displacements of the center of pressure (CP) were decomposed along mediolateral and anteroposterior axes and assessed through variance positions and parameters obtained from fractional Brownian motion (fBm) modeling to determine the nature and the spatiotemporal organization of the successive controlling mechanisms. The variances underline the relative independence of the two tasks. Nevertheless, as highlighted by the fBm framework, postural correction is initiated for the unipedal stance after shorter time delays and longer covered distances. When compared to bipedal standing, one of the main characteristics of unipedal standing is to induce better-controlled CP trajectories, as deduced from the scaling regimes computed from the fBm modeling. Lastly, the control of the CP trajectories during the shortest time intervals along the anteroposterior axis appears identical for both uni- and bipedal conditions. Unipedal and bipedal standing controls should thus be viewed as two complementary tasks, each providing specific and complementary insights into the postural control organization.

Restricted access

E. Paul Zehr, Sandra R. Hundza, Jaclyn E. Balter and Pamela M. Loadman

We used amplitude modulation of cutaneous reflexes during leg cycling as a paradigm to investigate neural control mechanisms regulating forward (FWD) and backward (BWD) rhythmic limb movement. Our prediction was a simple reversal of reflex modulation during BWD leg cycling and context-dependent reflex modulation. Cutaneous reflexes were evoked by electrical stimulation delivered to the superficial peroneal (SP) and distal tibial (TIB) nerves at the ankle. EMG recordings were collected from muscles acting at the hip, knee, and ankle. Kinematic data were also collected at these joints. Cutaneous reflexes were analyzed according to the phase of movement in which they were evoked. When functional phases (i.e., flexion or extension) of cycling were matched between FWD and BWD, background EMG and reflex modulation patterns were generally similar. The reflex patterns when compared at similar functional phases presented as a simple reversal suggesting FWD and BWD cycling are regulated by similar neural mechanisms. The general reflex regulation of limb trajectory was maintained between cycling directions in accordance with the task requirements of the movement direction.

Restricted access

Shannon D.R. Ringenbach, Kristina Zimmerman, Chih Chia Chen, Genna M. Mulvey, Simon D. Holzapfel, Daniel J. Weeks and Michael H. Thaut

The present study used a synchronization-continuation paradigm during continuous bimanual drumming with different cues in 17 persons with Down syndrome, eight typical persons with similar mental age and eight typical persons with similar chronological age. The task required participants to hit two drums with their hands at the same time following music (e.g., a tune with various decibel drum beats), auditory (e.g., sound of drumbeat), verbal (e.g., voice saying “drum”), and visual (e.g., video of both hands moving up and down and hitting the drums together) cues for 10 seconds, then continue drumming in the absence of cues for another 10 seconds. In general, when all groups were following the music cues their movements were faster as compared with their movements in the auditory, verbal, and visual conditions. In addition, when following visual cues all groups produced more accurate and consistently coordinated movements than with the other cue types. Further, participants with Down syndrome often stopped moving when the pacing cues were eliminated indicating a need for continuous cues for continuous movements.

Restricted access

Ann L. Smiley-Oyen, Sonja A. Hall, Kristin A. Lowry and John P. Kerr

We investigated the effects of extensive practice of rapid aiming on bradykinesia and, more specifically, generation of peak velocity, in discrete rapid aiming and in transfer to reach-to-grasp. Twenty-one participants (seven young adults, seven older adults, and seven adults with mild to moderate Parkinson’s disease (PD) while on medication) engaged in eight practice periods per week for three weeks (> 700 trials), with changes in performance measured weekly. Retention was measured weekly for three weeks postpractice. Movement time decreased with one week of practice, primarily due to a decrease in time-to-peak velocity. With practice and after retention, the PD group generated peak velocity as consistently as both neurologically healthy groups, but remained more variable in time-to-peak velocity. Transfer was observed in the neurologically healthy groups, but not in the PD group. We concluded that short-term practice (one week in our paradigm) is sufficient for decreasing movement time, but more extensive practice is needed to improve consistency of rapid aiming performance for people with mild to moderate PD.

Restricted access

Tsung-Yu Hsieh, Matheus M. Pacheco and Karl M. Newell

The goal of present experiment was to test whether different speed-accuracy paradigms outcomes (time minimization and time matching) were due to different temporal and spatial task constraints. Fifteen participants twice performed 100 trials of time minimization and time matching tasks with the yoked temporal and spatial requirements (criterion time and target width). The results showed that performing an aiming movement under the same spatial and temporal constraints resulted in similar outcomes with distributional properties (skewness and kurtosis) being slightly affected by practice effects. There was a trade-off in the information entropy for space and time (temporal information entropy decreased as spatial information entropy increased) with practice. Nevertheless, the joint space-time entropy of outcome did not change across tasks and conditions—revealing a common level of space-time entropy between these two categories of aiming tasks. These findings support the hypothesis that under the same spatial and temporal constraints the movement speed-accuracy function shares the same properties independent of task category.

Restricted access

Clayton L. Van Doren

The purpose of this study was to determine whether direct measurements of grasp stiffness agreed with stiffness inferred from the slopes of isovolitional force-span characteristics derived from previous grasp-effort matching data. Grasp stiffness for three-finger pinch was measured as a function of initial force and finger span using step displacements applied in a do-not-intervene paradigm. Subjects pinched a free-floating, motorized manipulandum in each hand and squeezed both with equal effort; one of the hands was perturbed at random. Stiffness was calculated from the initial and final steady-state values of force and span. The effects of step amplitude, rise-time, and initial load stiffness were investigated; grasp stiffness decreased significantly for larger steps, increased slightly for longer rise-times, and was unaffected by load stiffness. Grasp stiffness then was measured as a function of initial force and span using a single set of step parameters. Stiffness increased significantly in proportion to force but was changed only slightly by span. It was concluded that the perturbation and effort-matching measures of stiffness are not equivalent and represent different components of motor behavior.