The purpose of the current study was to examine motion enslaving characteristics of multiple fingers during isolated flexion of the distal interphalangeal joints. Because the distal interphalangeal joints are flexed by multiple tendons of the single flexor digitorum profundus, the current experimental design provided a unique advantage to understand inter-finger enslaving effects due to the flexor digitorum profundus. Eight subjects were instructed to flex the distal inter-phalangeal joint of each individual finger from the fully extended position to the fully flexed position as quickly as possible. Maximal angular displacements, velocities, or accelerations of individual fingers were used to calculate the enslaving effects. An independence index, defined as the ratio of the maximal displacement of a master finger to the sum of the maximal displacements of the master and slave fingers, was used to quantify relative independence of each finger. The angular displacements of the index, middle, ring, and little fingers were 68.6° (±7.7), 68.1° (±10.1), 68.1° (±9.7), and 74.7° (±13.3), respectively. The motion of a master finger was invariably accompanied by motion of 1 or 2 slave fingers. Angular displacements of master and slave fingers increased to maximum values with time monotonically. Velocity curves demonstrated bell-shaped profile, and the acceleration curves were sinusoidal. Enslaving effects were generated mainly on the neighboring fingers. The amount of enslaving on the middle and ring fingers exceeded more than 60% of their own maximum angular displacements when a single adjacent finger moved. The index finger had the highest level of independence as indicated by the lowest enslaving effects on other fingers or by other fingers. The independence indices of the index, middle, ring, and little fingers were 0.812 (±0.070), 0.530 (±0.051), 0.479 (±0.099), and 0.606 (±0.148), respectively. In all tasks, motion of slave fingers always lagged with respect to the master finger. Time delays, on average, ranged from 7.8 (±5.0) to 35.9 (±22.1) ms. Our results suggest that there exist relatively large enslaving effects among the compartments of the flexor digitorum profundus, and functional independence of fingers in daily activities is likely enhanced through synergistic activities of multiple muscles, including flexors and extensors.
Zong-Ming Li, Shouchen Dun, Daniel A. Harkness and Teresa L. Brininger
Edwin M. Robertson
The concept of canonical representations within the motor system has been both supported and refuted using a variety of behavioral studies. Here, based upon neurophysiological data, I discuss the relationship amongst those neuronal substrates of action and the behavioral components of a movement. A novel view of reaching and grasping has been proposed which predicts that movements with similar kinematic and dynamic properties have a similar representation within the nervous system (Smeets & Brenner, 1999). However this is broadly inconsistent with a variety of neurophysiological findings that emphasize the independence amongst representations of action.
Edward Archer, Amanda E. Paluch, Robin P. Shook and Steven N. Blair
Successful aging encompasses more than just the prevention of disease and disability; the truly well-lived life is demonstrated by a sense of vitality and independence, freedom from bodily pain, and the continued involvement in meaningful activities. While physical inactivity and sedentary behaviors accelerate the aging process, deliberate exercise and other forms of activity delay and/or prevent the onset of age-related pathologies such as frailty, osteoporosis, sarcopenia, and cardiovascular disease. This review surveys the evidence that supports the position that physical activity is a necessary component for the development and maintenance of the physiological resources that are foundational to physical and cognitive functioning and ‘living well’ in one's later years.
Linda C. Campanelli
Functional mobility is generally considered a major contributor to maintaining quality of life at any age. There are several overviews of physiological aging relative to physical functioning and/or mobility in the recent literature. This paper reiterates the need for continued exercise (at all levels) throughout one’s lifetime, specifically to enhance quality of life and functional independence. Implications for professionals and program development are included. Tailored exercises for both ambulatory and nonambulatory older adults to maintain flexibility, gait, and bed mobility are described.
Donna L. Goodwin, David A. Fitzpatrick, Robin Thurmeier and Carol Hall
This phenomenological study explored the decision-making experience of parents whose children joined Special Olympics programs. The experiences of 16 families with children 10-22 years old were gathered through interviews, artifacts, and field notes. Three themes emerged from the thematic analysis (a) thoughtful instruction, (b) finding the fit, and (c) security of acceptance. Parents sought instructors who were interested in building relationships with their children and creating anxiety-free instructional environments for them. A good program fit occurred when instructors had expectations for motor skill development and increased independence. Parents also preferred environments that encouraged meaningful peer interactions. The findings were interpreted within the context of self-determination theory.
Jacquelyn Cuneen and M. Joy Sidwell
Internships permit sport management students to link classroom learning to the professional environment. Since internships provide students with opportunities to learn on-the-job and test their skills in the marketplace, the experiences should be uniformly beneficial to all students regardless of gender. This study was conducted to describe internship work conditions (i.e., opportunities to perform in essential marketplace functions) for male and female sport management interns assigned to ‘Big Four’ professional sport organizations. Participants were 74 sport industry professionals who supervised a total of 103 interns over a one-year period. A X2 Test of Independence found that male and female interns working in professional sport had comparable opportunities to perform and learn on the job. Differences in opportunity, hiring practices, and on-the-job benefits emerged primarily as a function of job specialization (e.g., operations, marketing, venue management), league/association, or gender of the internship supervisor rather than gender of the interns.
Jae Kun Shim, Jeffrey Hsu, Sohit Karol and Ben F. Hurley
The purpose of the current study was to investigate the effects of finger strength training (ST) on finger strength, independence, force control, and adaptations in multifinger coordination. Thirty-three healthy, young (23.0 ± 2.9 years) subjects were randomly assigned into 4 groups. Group 1 (G1) trained all fingers together, Group 2 (G2) trained individual fingers without restricting movements of the non-training fingers, and Group 3 (G3) trained individual fingers while restricting the movement of the nontraining fingers. The control group (G0) did not undergo any training. A vertically hanging load was attached to a spring that passed through a pulley. The other end of the string extended to the horizontal plane and had thimbles attached to it. Subjects were asked to rest their forearm on the table and lift the load by inserting their fingers into the thimbles. The training protocol lasted 6 weeks. Identical experimental tests were conducted 4 times, biweekly, across the 6-week training. Force coordination and moment coordination, defined as synergies stabilizing the resultant force and the resultant moment of all finger forces, in a multifinger pressing task were quantified using the Uncontrolled Manifold (UCM) analysis. The UCM analysis allocates motor variability into two components, one in the null space of a motor task and the other perpendicular to the null space. During multifinger pressing tasks, multifinger coordination exists when the variability in the null space is greater than the variability in the subspace perpendicular to the null space. The multifinger coordination was quantified as the difference between the variance within the null space and that perpendicular to the null space, normalized by the total variance. Thus, the coordination measure in our analysis is a unitless variable. A greater coordination measure indicates better multifinger coordination. Moment-stabilizing multifinger coordination increased only in G1 (from 1.197 ± 0.004 to 1.323 ± 0.002, p < .01), and force-stabilizing coordination increased only in G3 (from 0.207 ± 0.106 to 0.727 ± 0.071, p < .01). Finger strength, measured by the maximal voluntary finger force of pressing 4 fingers, increased significantly in all training groups (from 103.7 ± 3.1 N to 144.0 ± 3.6 N for training groups, all p < .001). Finger-force errors, quantified by the deviations between the required force profiles (20% maximal voluntary force) presented to the subjects and the actual force produced, decreased significantly with ST for all the training groups (all p < .05). Finger independence also decreased significantly for all the training groups (p < .05). We conclude that the neuromuscular system adaptations to multifinger ST are specific to the training protocol being employed, yielding improvements in different types of multifinger coordination (i.e., coordination-specific ST), finger-force control, and finger strength and a decrease in finger independence. Finger independence, depending on the nature of the task, might or might not be favorable to certain task performances. We suggest that ST protocol should be carefully designed for the improvement of specific coordination of multieffector motor systems.
Janet B. Parks and Michael E. Bartley
Scholarship expectations of many universities in the United States are becoming more stringent. The purpose of this study was to examine variables associated with the scholarship of the sport management professoriate. The participants were 266 of the 422 academics in the NASPE-NASSM Sport Management Program List (1991). Chi-square tests of independence (alpha < .004) revealed slight tendencies for (a) younger faculty to have doctorates in areas such as sport management, psychology/sociology of sport, and legal aspects of sport rather than in physical education; (b) younger faculty to have more publications than older faculty; (c) women to be concentrated in the lower ranks and salary ranges; and (d) movement toward gender parity in rank and salary. This study should be replicated in 5 years to discover if these tendencies were precursors of trends.
Bonnie Field, Tom Cochrane, Rachel Davey and Yohannes Kinfu
The aim of this study was to identify determinants of walking and whether walking maintained mobility among women as they transition from their mid-70s to their late 80s. We used 12 years of follow-up data (baseline 1999) from the Australian Longitudinal Study on Women’s Health (n = 10,322). Fifteen determinants of walking were included in the analysis and three indicators of mobility. Longitudinal data analyses techniques were employed. Thirteen of the 15 determinants were significant predictors of walking. Women in their mid-70s who walked up to 1 hr per week were less likely to experience loss of mobility in very old age, including reduced likelihood of using a mobility aid. Hence, older women who do no walking should be encouraged to walk to maintain their mobility and their independence as they age, particularly women in their 70s and 80s who smoke, are overweight, have arthritis, or who have had a recent fall.
Joseph F. Signorile, David Sandler, Fangchao Ma, Steve Bamel, Damian Stanziano, Wes Smith, Bernard A. Roos and Lauran Sandals
This study examined the validity, reliability, and discriminatory capacity of the gallon-jug shelf-transfer (GJST) test. Six hundred fifty-three independent-living older adults (463 women age 72.9 ± 7.0 years, 190 men age 74.3 ± 6.7 years) participated. Participants moved five 1-gallon jugs (≈3.9 kg) from a knee-high to a shoulder-high shelf as quickly as possible. The GJST showed an exponential performance decline with age, and there were significant correlations between the GJST and common functional tests (p < .001). High within-day and between-days reliability was detected. The test also detected differences resulting from training status (p < .01) and training protocols (p < .05). The GJST is a valid, reliable, inexpensive, safe, and easily administered clinical test for identifying physically vulnerable elders who could benefit from interventions such as exercise to improve their physical capacities and maintain independence.