In this paper, I argue that physical activity in the form of exercise provides wonderful health benefits for individuals with chronic stroke but fails to also reduce the wider effects of disability for these individuals. The argument proceeds first with a definition of terms, including the classification framework of health and disability according to the World Health Organization. Next follows a section on stroke, its prevalence, and major motor symptoms, including health status. The subsequent two sections include evidence for the health benefits of exercise and lack of evidence for the reduction of disability. The penultimate section expands upon the direction of research that should move us toward reducing disability. The final section concludes on how kinesiology fits into a model for improving both health and reducing disability for chronic stroke survivors.
Larry Forrester and Jill Whitall
The effects of directional and postural constraints on preferred speed quadrupedal gait patterns were studied by comparing responses to four hand-foot crawling tasks: forward and backward prone (FP and BP) and forward and backward supine (FS and BS). A central question was whether the task dynamics evident at the end-effector level also appear at the joint effector system level. Timing of reversals in each limb's proximal effector system joints was shown to be related to the functional role (propulsion or reaching) of the limb. Within joints, task constraint changes strongly tended to affect reversal times, and time-reversed directional comparisons tended to show “mirroring” responses. Peak reaching positions were also closely associated with forelimb touchdowns and interlimb coordination. Discussion centers on task function, task dynamics, and their influence on effector system behavior.
Nancy Getchell, Susan McMenamin and Jill Whitall
This study examines gross motor coordination in children with and without learning disabilities using a dynamical systems perspective. In a dual motor task paradigm (walk/clap, gallop/clap), we measured and compared frequency and phase locking and consistency within and across trials in 12 children with learning disabilities and 12 age-matched typically developing children. In the walk/clap condition, groups differed in consistency and in entrainment (increased frequency of 4 limb coupling) over short-term practice. In the gallop/clap condition, groups differed in consistency; neither group showed entrainment. Comparisons within the LD group of participants with and without diagnosed visual-motor problems showed differences in classification, consistency, and entrainment. These results suggest that gross motor coordination tasks provide information about as well as a novel opportunity for early identification of learning disabilities.
Wei Liu, Jill Whitall and Thomas M. Kepple
Functional arm reaching involves multilinked joints: shoulder, elbow, and wrist. We propose that induced position analysis is a useful analytical tool for multijoint coordination of arm reaching. This method was used to compute the contributions of the net joint moment to the hand position when reaching forward. We describe the method and give examples of validating this model with motion capture data. The shoulder and elbow were prime movers of the arm: both acted together with an “overshoot” and “undershoot” pattern respectively to move the hand forward into the final position.
Jill Whitall, Larry Forrester and Nancy Getchell
The present study examined the effect of nonspecific task constraints on the multilimb coordination task of preferred-speed crawling. Adult subjects undertook three trials each of the following randomly ordered conditions: forward prone (FP), backward supine (BS), backward prone (BP) and forward supine (FS). Subjects adopted specific coordinative solutions consistent with task-related function rather than anatomical specification. The patterns were relatively stable, with BP being least stable. Across conditions, subjects changed their velocity in a predictable order that corresponded to the various constraints. These velocity changes were largely attributable to stride length adjustments and not limb frequency. Within a condition, neither velocity nor anthropometrics appeared to influence the coordinative solution. Overall, rather large differences were found in coordinative solutions, possibly owing to the nature of the tasks and/or individual searching strategies. The results were interpretable within a dynamic approach to coordination and support the idea that coordination is functionally rather than anatomically determined.
Kimberly B. Harbst, Jo-Anne C. Lazarus and Jill Whitall
The purpose of this study was to investigate how children and adults control bimanual activities with the influence of kinematic variables minimized. Force and timing measures were analyzed in self-paced, isometric bimanual pinch tasks performed by 6-, 8-, 10-, 12-year-old, and adult subjects. Subjects (n = 84) performed four tasks (inphase symmetrical, antiphase reciprocal, inphase asymmetrical force-right high, inphase asymmetrical force-left high) cycling between low levels (10-30%) of maximal volitional force during three 15-s trials. Bimanual tasks requiring similar activation between the hands were performed more accurately, more quickly, and with less force and timing variability than tasks requiring different actions and/or levels of force to be produced simultaneously. Evidence of force entrainment between the hands was exhibited when force direction (increasing vs. decreasing) was similar between hands but greater relative force was required of the left hand. Lower accuracy and greater variability resulted when controlled decrement of force was required to reach the lower force targets as opposed to the upper force targets which required subjects to increase force. Subjects in the two youngest age groups exhibited lower force accuracy and greater force and timing variability relative to older children and adults. Twelve-year-old subjects approximated adults' performance in all variables.
Kevin McQuade, Michelle L. Harris-Love and Jill Whitall
The purpose of this study was to determine whether the phenomenon of bilateral deficit in muscular force production observed in healthy subjects and mildly impaired stroke patients also exists in patients with more chronic and greater levels of stroke impairment. Ten patients with chronic hemiparesis resulting from stroke performed unilateral and bilateral maximal voluntary isometric contractions of the elbow flexors. When the total force produced by both arms was compared, 12% less force was produced in the bilateral compared with unilateral condition (p = 0.01). However, studying the effect of task conditions on each arm separately revealed a significant decline in nonparetic (p = 0.01) but not paretic elbow flexor force in the bilateral compared with unilateral condition. Results suggest that a significant bilateral force deficit exists in the nonparetic but not the paretic arm in individuals with chronic stroke. Bilateral task conditions do not seem to benefit or impair paretic arm maximal isometric force production in individuals with moderate-severity chronic stroke.
Margaret A. Finley, Laura Dipietro, Jill Ohlhoff, Jill Whitall, Hermano I. Krebs and Christopher T. Bever
We are expanding the use of the MIT-MANUS robotics to persons with impairments due exclusively to orthopedic disorders, with no neurological deficits. To understand the reliability of repeated measurements of the robotic tasks and the potential for registering changes due to learning is critical. Purposes of this study were to assess the learning effect of repeated exposure to robotic evaluations and to demonstrate the ability to detect a change in protocol in outcome measurements. Ten healthy, unimpaired subjects (mean age = 54.1 ± 6.4 years) performed six repeated evaluations consisting of unconstrained reaching movements to targets and circle drawing (with and without a visual template) on the MIT-MANUS. Reaching outcomes were aiming error, mean and peak speed, movement smoothness and duration. Outcomes for circle drawing were axis ratio metric and shoulder–elbow joint angles correlation metric (was based on a two-link model of the human arm and calculated hand path during the motions). Repeated-measures ANOVA (p ≤ .05) determined if difference existed between the sessions. Intraclass correlations (R) were calculated. All variables were reliable, without learning across testing sessions. Intraclass correlation values were good to high (reaching, R ≥ .80; circle drawing, R ≥ .90). Robotic measurement ability to differentiate between similar but distinct tasks was demonstrated as measured by axis ratio metric (p < .001) and joint correlation metric (p = .001). Outcome measures of the MIT-MANUS proved to be reliable yet sensitive to change in healthy adults without motor learning over the course of repeated measurements.
Jane E. Clark, Farid Bardid, Nancy Getchell, Leah E. Robinson, Nadja Schott and Jill Whitall
Motor development research has had a rich history over the 20th century with a wide array of scientists contributing to a broad and deep body of literature. Just like the process of development, progress within the field has been non-linear, with rapid periods of growth occurring after the publication of key research articles that changed how we conceptualized and explored motor development. These publications provided new ways to consider developmental issues and, as a result, ignited change in our theoretical and empirical approaches within the field of motor development and the broader field of developmental psychology. In this paper, we outline and discuss six pioneering studies that we consider significant in their impact and in the field’s evolution, in order of publication: Halverson, 1931; Wild, 1938; Gibson & Walk, 1960; Connolly, Brown, & Bassett, 1968; Thelen & Fisher, 1982; Thelen & Ulrich, 1991. We have limited this review to empirical papers only. Together, they offer insight into what motor development research is, where it came from, why it matters, and what it has achieved.