The Quick Step measures reaction time and lateral stepping velocity. Upon a visual cue, participants step to the side as quickly as possible. Instrumentation includes floor pads with pressure-sensitive switches and two timers. In all, 109 older adults who had experienced a recent fall, 46 older adult nonfallers, and 24 young adults volunteered for testing. Reliability for reaction time and stepping velocity was good to excellent (intraclass correlation = 0.69–0.85). Multivariate analysis of variance revealed a significant difference between groups, p < 0.01, but not between stepping directions, p = 0.62–0.72, for both reaction time and stepping velocity. Reaction times were different among the three groups, p < 0.01, with the young adults having the fastest times and the older adult fallers having the slowest times. Lateral stepping velocity was faster among the young adults than for the two older groups, p < 0.01, but did not differ between the older adults, p = 0.29. It is concluded that the Quick Step is a simple and reliable tool for determining reaction time and lateral stepping velocity, and that this test can be used to detect a significant difference in reaction time between older adult fallers and nonfallers.
Karen N. White, Katherine B. Gunter, Christine M. Snow, and Wilson C. Hayes
Timothy A. Hanke, Bruce Kay, Michael Turvey, and David Tiberio
important factor in whether or not the step serves its functional purpose ( Rogers, Johnson, Martinez, Mille, & Hedman, 2003 ; Sparto, Jennings, Furman, & Redfern, 2014 ). It has become increasingly apparent that there is a relationship between lateral stability, advancing age, and falls ( Mille et
David Rhodes, Mark Leather, Daniel Birdsall, and Jill Alexander
.21), 8% 1.45 (0.17), 19% M–L 1.54 (0.25), 1% 1.39 (0.21), 4% 1.14 (0.18), 11% 0.99 (0.10), 20% 1.89 (0.31), +21% 1.56 (0.19), +17% 1.37 (0.22), +6% 1.22 (0.19), 18% Abbreviations: A–P, anterior–posterior stability; M–L, medial–lateral stability; OSI, overall stability index. All values in the table are
David Rhodes, Jill Alexander, and Matt Greig
anterior–posterior stability; M-L, medial–lateral stability; OSI, Overall Stability Index. With the data set collapsed to consider the temporal pattern of recovery for each direction of stability, all directions displayed a significant effect of time (OSI: F = 3.98, P = .005, η 2 = .16; A-P: F = 2
Benno M. Nigg, Edward C. Frederick, Michael R. Hawes, and Simon M. Luethi
Pain, discomfort, and/or injuries in tennis can be influenced by the individual movement pattern and the external and/or internal boundary conditions. The influence of external boundary conditions on the occurrence of short-term pain was studied in a prospective study with 229 subjects. The boundary conditions investigated were shoe, temperature, type and length of game and subjective assessment of comfort, sole grip, and lateral stability Pain was reported by 40% of the 171 subjects included in the final analysis. It was frequently reported in the first two playing sessions but less frequently afterward. Discomfort was the dominant type of pain, accounting for 71.6% of all reported cases. The foot was the major site of pain (85%). The boundary conditions influencing pain were found to be the shoe (the more flexible shoe 1 had less pain than the suffer shoe 2), the type of game (competitive more than recreational), and the length of the game (longer playing sessions with more pain). Subjective assessment of comfort, sole grip, and lateral support also showed differences for the pain/no pain groups. Subjects who complained about these aspects were more frequently in the pain groups. The results show that the occurrence of pain in tennis can be influenced by various external boundary conditions.
Jebb G. Remelius, Joseph Hamill, Jane Kent-Braun, and Richard E.A. Van Emmerik
Individuals with multiple sclerosis (MS) often have poor balance control that is especially apparent during dynamic tasks such as gait initiation (GI). The purpose of this study was to investigate how balance symptoms due to MS alter spatiotemporal variables, coordination, and temporal margins within the stability boundary during gait initiation. Twelve women with MS (Expanded Disability Status Scale [EDSS] mean = 4.0, SD = 1.4) and 12 women without MS (control group) initiated gait at their preferred speed. MS participants attained a slower anterior velocity because of smaller anterior center of mass displacements and took longer to complete the initiation of gait than the control group. MS participants exhibited a smaller posterior shift in center of pressure during GI and stepped with a longer dual support time than the control group. However, these changes may be due to differences in initiation velocity. Relative timing analysis showed invariance in postural and locomotor phases of gait initiation between groups. The MS group showed different coordination between anterior-posterior and medio-lateral center of pressure components while increasing temporal margins to the posterior and lateral stability boundaries in comparison with the control group. Overall, during gait initiation at their preferred speed the MS participants adopted a functional strategy that produces lower speed and reduced proximity to the stability boundaries prior to stepping.
Nooranida Arifin, Noor Azuan Abu Osman, and Wan Abu Bakar Wan Abas
The measurements of postural balance often involve measurement error, which affects the analysis and interpretation of the outcomes. In most of the existing clinical rehabilitation research, the ability to produce reliable measures is a prerequisite for an accurate assessment of an intervention after a period of time. Although clinical balance assessment has been performed in previous study, none has determined the intrarater test-retest reliability of static and dynamic stability indexes during dominant single stance. In this study, one rater examined 20 healthy university students (female = 12, male = 8) in two sessions separated by 7 day intervals. Three stability indexes—the overall stability index (OSI), anterior/posterior stability index (APSI), and medial/lateral stability index (MLSI) in static and dynamic conditions—were measured during single dominant stance. Intraclass correlation coefficient (ICC), standard error measurement (SEM) and 95% confidence interval (95% CI) were calculated. Test-retest ICCs for OSI, APSI, and MLSI were 0.85, 0.78, and 0.84 during static condition and were 0.77, 0.77, and 0.65 during dynamic condition, respectively. We concluded that the postural stability assessment using Biodex stability system demonstrates good-to-excellent test-retest reliability over a 1 week time interval.
Alison C. Novak and Brenda Brouwer
This study describes and contrasts the kinematics and kinetics of stair ambulation in people with chronic stroke and healthy control subjects. Three-dimensional motion data were collected from 10 persons with stroke (7 males) and 10 sex and age-matched older adults as they ascended and descended an instrumented staircase at self-selected speed with and without a handrail. Ankle, knee and hip joint angle and moment profiles were generated during stance and range of motion and peak moments were contrasted between groups, sides (stroke only) and condition. Cadence was lower in stroke than controls, although the kinematic profiles appeared similar during ascent and decent. Notable differences in joint kinetics were evident as the peak extensor moments were typically lower on the affected side in stroke compared with controls and the less affected side. These differences accounted for the lower magnitude net extensor support moment. The lower affected side hip abductor moments likely limited lateral stability. Handrail use tended to reduce the peak moments on the affected side only leading to more side-to-side differences than occurred without the handrail. The findings reveal differences in task performance between stroke and healthy groups that help inform rehabilitation practice.
Alice D. LaGoy, Caleb Johnson, Katelyn F. Allison, Shawn D. Flanagan, Mita T. Lovalekar, Takashi Nagai, and Chris Connaboy
the first 3 seconds after initial contact, defined as when vertical ground reaction forces exceeded 5% body mass, were used to calculate dynamic postural stability index. 27 Anterior–posterior stability index = ∑ ( 0 − y ) 2 number of data points ÷ BW , Medial–lateral stability index = ∑ ( 0 − x ) 2
Renato Claudino, Marcio José dos Santos, and Giovana Zarpellon Mazo
, Hayes, & McMahon, 2001 ). Lateral stability in older populations has been studied in investigations by Rogers and Mille (see Rogers & Mille, 2003 for review). These investigations involved analyzing the protective stepping strategy that has been altered in the older adults. They usually take a