Matching Items (75)
Description
During the downswing all golfers must roll their forearms and twist the club handle in order to square the club face into impact. Anecdotally some instructors say that rapidly twisting the handle and quickly closing the club face is the best technique while others disagree and suggest the opposite. World class golfers have swings with a range of club handle twist velocities (HTV) from very slow to very fast and either method appears to create a successful swing. The purpose of this research was to discover the relationship between HTV at impact and selected body and club biomechanical characteristics during a driver swing. Three-dimensional motion analysis methods were used to capture the swings of 94 tour professionals. Pearson product-moment correlation was used to determine if a correlation existed between HTV and selected biomechanical characteristics. The total group was also divided into two sub-groups of 32, one group with the fastest HTV (Hi-HTV) and the other with the slowest HTV (Lo-HTV). Single factor ANOVAs were completed for HTV and each selected biomechanical parameter. No significant differences were found between the Hi-HTV and Lo-HTV groups for both clubhead speed and driving accuracy. Lead forearm supination velocity at impact was found to be significantly different between groups with the Hi-HTV group having a higher velocity. Lead wrist extension velocity at impact, while not being significantly different between groups was found to be positive in both groups, meaning that the lead wrist is extending at impact. Lead wrist ulnar deviation, lead wrist release and trail elbow extension velocities at maximum were not significantly different between groups. Pelvis rotation, thorax rotation, pelvis side bend and pelvis rotation at impact were all significantly different between groups, with the Lo-HTV group being more side bent tor the trail side and more open at impact. These results suggest that world class golfers can successfully use either the low or high HTV technique for a successful swing. From an instructional perspective it is important to be aware of the body posture and wrist/forearm motion differences between the two techniques so as to be consistent when teaching either method.
ContributorsCheetham, Phillip (Author) / Hinrichs, Richard (Thesis advisor) / Ringenbach, Shannon (Committee member) / Dounskaia, Natalia (Committee member) / Crews, Debra (Committee member) / Arizona State University (Publisher)
Created2014
Description
Dexterous manipulation is a representative task that involves sensorimotor integration underlying a fine control of movements. Over the past 30 years, research has provided significant insight, including the control mechanisms of force coordination during manipulation tasks. Successful dexterous manipulation is thought to rely on the ability to integrate the sense of digit position with motor commands responsible for generating digit forces and placement. However, the mechanisms underlying the phenomenon of digit position-force coordination are not well understood. This dissertation addresses this question through three experiments that are based on psychophysics and object lifting tasks. It was found in psychophysics tasks that sensed relative digit position was accurately reproduced when sensorimotor transformations occurred with larger vertical fingertip separations, within the same hand, and at the same hand posture. The results from a follow-up experiment conducted in the same digit position-matching task while generating forces in different directions reveal a biased relative digit position toward the direction of force production. Specifically, subjects reproduced the thumb CoP higher than the index finger CoP when vertical digit forces were directed upward and downward, respectively, and vice versa. It was also found in lifting tasks that the ability to discriminate the relative digit position prior to lifting an object and modulate digit forces to minimize object roll as a function of digit position are robust regardless of whether motor commands for positioning the digits on the object are involved. These results indicate that the erroneous sensorimotor transformations of relative digit position reported here must be compensated during dexterous manipulation by other mechanisms, e.g., visual feedback of fingertip position. Furthermore, predicted sensory consequences derived from the efference copy of voluntary motor commands to generate vertical digit forces may override haptic sensory feedback for the estimation of relative digit position. Lastly, the sensorimotor transformations from haptic feedback to digit force modulation to position appear to be facilitated by motor commands for active digit placement in manipulation.
ContributorsShibata, Daisuke (Author) / Santello, Marco (Thesis advisor) / Dounskaia, Natalia (Committee member) / Kleim, Jeffrey (Committee member) / Helms Tillery, Stephen (Committee member) / McBeath, Michael (Committee member) / Arizona State University (Publisher)
Created2014
Description
Voluntary exercise has been shown to generate post exercise improvements in executive function within the attention-deficit hyperactivity disorder (ADHD) population. Research is limited on the link between exercise and motor function in this population. Whether or not changes in executive and motor function are observed under assisted exercise conditions is unknown. This study examined the effect of a six-week cycling intervention on executive and motor-function responses in young adult females with ADHD. Participants were randomized to either a voluntary exercise (VE) or an assisted exercise (AE) group. Both groups performed 30 minute cycling sessions, three times per week, at either a voluntary or assisted rate, on a modified Theracycle Model 200 motorized stationary cycle ergometer. The Mann-Whitney U tests were used to detect median differences between groups, and the Wilcoxon signed-rank tests were used to test median differences within groups. Executive function improvements were greater for AE compared to VE in activation (MDNAE = 162 vs. MDNVE = 308, U = .00, p = .076, ES = .79); planning (MDNAE = 51.0 vs. MDNAE = 40.5, U = .00, p = .083, ES = .77); attention (MDNAE = 13.0 vs. MDNVE = 10.0, U = .00, p = .083, ES = .77); and working memory (MDNAE = 10.0 vs. MDNVE = 6.5, U = .00, p = .076, ES = .79). Motor function improvements were greater for AE compared to VE in manual dexterity (MDNAE = 18 vs. MDNVE = 15.8, U = .00, p = .083, ES = .77); bimanual coordination (MDNAE = 28.0 vs. MDNVE = 25.3, U = .00, p = .083, ES = .77); and gross motor movements of the fingers, hands, and arms (MDNAE = 61.7 vs. MDNVE = 56.0, U = .00, p = .083, ES = .77). Deficits in executive and motor functioning have been linked to lifelong social and psychological impairments in individuals with ADHD. Finding ways to improve functioning in these areas is important for cognitive, emotional and social stability. Compared to VE, AE is a more effective strategy for improving executive and motor functioning in young adult females with ADHD.
ContributorsBirchfield, Natasha (Author) / Ringenbach, Shannon (Thesis advisor) / Lee, Chong (Committee member) / Chisum, Jack (Committee member) / Campbell, Kathyrn (Committee member) / Arizona State University (Publisher)
Created2014
Description
Humans moving in the environment must frequently change walking speed and direction to negotiate obstacles and maintain balance. Maneuverability and stability requirements account for a significant part of daily life. While constant-average-velocity (CAV) human locomotion in walking and running has been studied extensively unsteady locomotion has received far less attention. Although some studies have described the biomechanics and neurophysiology of maneuvers, the underlying mechanisms that humans employ to control unsteady running are still not clear. My dissertation research investigated some of the biomechanical and behavioral strategies used for stable unsteady locomotion. First, I studied the behavioral level control of human sagittal plane running. I tested whether humans could control running using strategies consistent with simple and independent control laws that have been successfully used to control monopod robots. I found that humans use strategies that are consistent with the distributed feedback control strategies used by bouncing robots. Humans changed leg force rather than stance duration to control center of mass (COM) height. Humans adjusted foot placement relative to a "neutral point" to change running speed increment between consecutive flight phases, i.e. a "pogo-stick" rather than a "unicycle" strategy was adopted to change running speed. Body pitch angle was correlated by hip moments if a proportional-derivative relationship with time lags corresponding to pre-programmed reaction (87 ± 19 ms) was assumed. To better understand the mechanisms of performing successful maneuvers, I studied the functions of joints in the lower extremities to control COM speed and height. I found that during stance, the hip functioned as a power generator to change speed. The ankle switched between roles as a damper and torsional spring to contributing both to speed and elevation changes. The knee facilitated both speed and elevation control by absorbing mechanical energy, although its contribution was less than hip or ankle. Finally, I studied human turning in the horizontal plane. I used a morphological perturbation (increased body rotational inertia) to elicit compensational strategies used to control sidestep cutting turns. Humans use changes to initial body angular speed and body pre-rotation to prevent changes in braking forces.
ContributorsQiao, Mu, 1981- (Author) / Jindrich, Devin L (Thesis advisor) / Dounskaia, Natalia (Committee member) / Abbas, James (Committee member) / Hinrichs, Richard (Committee member) / Santello, Marco (Committee member) / Arizona State University (Publisher)
Created2012
Description
The ultimate goal of human movement control research is to understand how natural movements performed in daily activities, are controlled. Natural movements require coordination of multiple degrees of freedom (DOF) of the arm. Here, patterns of arm joint control during daily functional tasks were examined, which are performed through rotation of the shoulder, elbow, and wrist with the use of seven DOF: shoulder flexion/extension, abduction/adduction, and internal/external rotation; elbow flexion/extension and pronation/supination; wrist flexion/extension and radial/ulnar deviation. Analyzed movements imitated two activities of daily living: combing the hair and turning the page in a book. Kinematic and kinetic analyses were conducted. The studied kinematic characteristics were displacements of the 7 DOF and contribution of each DOF to hand velocity. The kinetic analysis involved computation of 3-dimensional vectors of muscle torque (MT), interaction torque (IT), gravity torque (GT), and net torque (NT) at the shoulder, elbow, and wrist. Using a relationship NT = MT + GT + IT, the role of active control and the passive factors (gravitation and inter-segmental dynamics) in rotation of each joint was assessed by computing MT contribution (MTC) to NT. MTC was computed using the ratio of the signed MT projection on NT to NT magnitude. Despite the variety of joint movements required across the different tasks, 3 patterns of shoulder and elbow coordination prevailed in each movement: 1) active rotation of the shoulder and predominantly passive rotation of the elbow; 2) active rotation of the elbow and predominantly passive rotation of the shoulder; and 3) passive rotation of both joints. Analysis of wrist control suggested that MT mainly compensates for passive torque and provides adjustment of wrist motion according to requirements of both tasks. The 3 shoulder-elbow coordination patterns during which at least one joint moves largely passively represent joint control primitives underlying performance of well-learned arm movements, although these patterns may be less prevalent during non-habitual movements. The advantage of these control primitives is that they require minimal neural effort for joint coordination, and thus increase neural resources that can be used for cognitive tasks.
ContributorsMarshall, Dirk (Author) / Dounskaia, Natalia (Thesis advisor) / Schaefer, Sydney (Thesis advisor) / Buneo, Christopher (Committee member) / Arizona State University (Publisher)
Created2018
Description
The ultimate goal of human movement control research is to understand how natural movements performed in daily reaching activities, are controlled. Natural movements require coordination of multiple degrees of freedom (DOF) of the arm. Patterns of arm joint control were studied during daily functional tasks, which were performed through the rotation of seven DOF in the arm. Analyzed movements which imitated the following 3 activities of daily living: moving an empty soda can from a table and placing it on a further position; placing the empty soda can from initial position at table to a position at shoulder level on a shelf; and placing the empty soda can from initial position at table to a position at eye level on a shelf. Kinematic and kinetic analyses were conducted for these three movements. The studied kinematic characteristics were: hand trajectory in the sagittal plane, displacements of the 7 DOF, and contribution of each DOF to hand velocity. The kinetic analysis involved computation of 3-dimensional vectors of muscle torque (MT), interaction torque (IT), gravity torque (GT), and net torque (NT) at the shoulder, elbow, and wrist. Using the relationship NT = MT + GT + IT, the role of active control and passive factors (gravitation and inter-segmental dynamics) in rotation of each joint by computing MT contribution (MTC) to NT was assessed. MTC was computed using the ratio of the signed MT projection on NT to NT magnitude. Despite a variety of joint movements available across the different tasks, 3 patterns of shoulder and elbow coordination prevailed in each movement: 1) active rotation of the shoulder and predominantly passive rotation of the elbow; 2) active rotation of the elbow and predominantly passive rotation of the shoulder; and 3) passive rotation of both joints. Analysis of wrist control suggested that MT mainly compensates for passive torque and provides adjustment of wrist motion according to requirements of each task. In conclusion, it was observed that the 3 shoulder-elbow coordination patterns (during which at least one joint moved) passively represented joint control primitives, underlying the performance of well-learned arm movements, although these patterns may be less prevalent during non-habitual movements.
ContributorsSansgiri, Dattaraj (Author) / Dounskaia, Natalia (Thesis advisor) / Schaefer, Sydney (Thesis advisor) / Buneo, Christopher (Committee member) / Arizona State University (Publisher)
Created2018
Description
This study investigated the effect of a small added load on postural stability in older adults. Sixteen healthy older adults (6 male, 10 female, age=72 ± 3.2y, height=172± 9.3 cm, weight=84± 7.6 kg) performed clinical measures of postural control with different loads placed on the shoulders (0%, 1% and 3% bodyweight). The functional reach test, comprising a forward, right and left lateral reach, along with COP data measured through the use of a force plate were the postural control measures utilized in this study. COP data used were COP sway velocity and COP mean sway area, in the form of a 95% confidence ellipse. During the COP trials, visual input (eyes open and eyes closed) and surface conditions (firm and foam) were varied to evaluate the effect of the loads under different conditions. Two trials of each measurement were performed for all tests, and participants were allowed rest intervals as needed. Anticipated results show a decreased reach distance of 8% in the forward direction, and a 7% decrease in the left and right lateral directions under a 1% bodyweight load. For expected results of COP velocity, there will be a 12% increase from baseline COP sway velocity in the 1% bodyweight condition. Anticipated results for COP sway area show a 39% increase in the eyes open firm surface, under a 1% bodyweight load, and a 40% increase under the 3% load. These expected results show a significant effect on postural control with a 1% and 3% bodyweight load placed on the shoulders of older adults. This information may be valuable in combatting the epidemic of falls seen among the elderly population, as part of an exercise program for improving balance and postural stability.
ContributorsScherwinski, Eric (Author) / Dounskaia, Natalia (Thesis director) / Vidt, Meghan (Committee member) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Previous research has found improvements in motor and cognitive measures following Assisted Cycle Therapy (AC) in adolescence with Down syndrome (DS). Our study investigated whether we would find improvements in mental health in older adults with DS as measured from the Adapted Behavior Dementia Questionnaire (ABDQ), Physical Activity Self Efficacy Scales (PACES), Children's Depressive inventory, which are early indicators of Alzheimer's disease (AD) in persons with Down syndrome. This study consisted of seven participants with Down syndrome between the ages of 31 and 54, inclusive, that cycled for 30 minutes 3 x/week for eight weeks either at their voluntary cycling rate (VC) or approximately 35% faster with the help of a mechanical motor (ACT). Our results were consistent with our prediction that self efficacy improved following ACT, but not VC. However, our results were not consistent with our prediction that dementia and depression were improved following ACT more than VC. These results were interpreted with respect to the effects of exercise in older adults with DS. Future research should focus on recruiting more participants, especially those with deficits in mental health.
ContributorsPandya, Sachin (Author) / Ringenbach, Shannon (Thesis director) / Coon, David (Committee member) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
This study examines the effect of exercise therapy on a stationary bike on cognitive function, specifically inhibition and set-switching, in adolescents with Down syndrome. 44 participants were randomly divided between the voluntary cycling therapy group (VCT) (i.e., self-selected cadence), assisted cycling therapy group (ACT) (i.e., 30% faster than self-selected cadence accomplished by a motor), and a control group (NC) in which the participants did not undergo any exercise therapy. Both cycling groups rode a stationary bicycle, for 30 minutes, three times a week, for eight-weeks. At the beginning (i.e., pretest) and end (i.e., posttest) of the eight-week session the participants completed tasks to evaluate their cognitive function. They completed three trials of the card sort test (i.e., set-switching) and three trials of the knock-tap test (i.e, inhibition) before and after eight-weeks of cycling therapy. The scores of these tests were analyzed using one-way ANOVA between groups and paired samples t-tests. The results showed that after eight-weeks of cycling therapy the participants in the VCT group performed worse in the knock-tap test, but improved in two trials of the card sort test. The results also showed that the participants in the ACT group performed worse after eight-weeks of exercise therapy in one trial of the card sort test. No significant changes were seen for the control group. Due to the fact that on average the participants in the VCT group cycled with a higher heart rate, our results suggest exercise that significantly elevates heart rate can improve cognitive function, specifically set-switching, in adolescents with Down syndrome.
ContributorsBenson, Alicia Meigh (Author) / Ringenbach, Shannon (Thesis director) / Amazeen, Eric (Committee member) / Maraj, Brian (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
This study examines cognitive planning in adolescents with Down syndrome (DS) following an 8-week assisted cycling therapy intervention. Forty-three participants were randomly assigned to assisted cycling (AC) (i.e., at least 30% faster than self-selected cadence accomplished by a motor), voluntary cycling (VC) (self-selected cadence), and no cycling (NC) control group. Both AC and VC rode a stationary bicycle three times/week, 30 minutes/session, for eight weeks in duration. Participants completed cognitive testing that assessed cognitive planning at the beginning (i.e., pretest) and end (i.e., posttest) of the 8-week intervention. Consistent with our hypothesis, the results showed that cognitive planning improved following eight weeks of cycling for the AC group. The same results were not seen for individuals in the VC or NC groups. Our results suggest that assisted cycling therapy may induce permanent changes in the prefrontal cortex in adolescents with DS.
ContributorsMillar, Kelsey Leann (Author) / Ringenbach, Shannon (Thesis director) / Amazeen, Eric (Committee member) / Barrett, The Honors College (Contributor) / School of Nutrition and Health Promotion (Contributor)
Created2015-05