Thursday-Abstracts

Thursday, May 30, 2013
S298 Vol. 45 No. 5 Supplement
1529 Board #121 May 30, 2:00 PM - 3:30 PM
Examination of sustained Gait speed in Individuals with
Chronic stroke
Tracy A. Dierks1 , Peter A. Altenburger1 , Kristine K. Miller2 ,
Rebecca L. Phipps3 , Arlene A. Schmid2 . 1Indiana University,
Indianapolis, IN. 2Roudebush VA Medical Center, Indianapolis,
IN. 3Indiana University Health, Indianapolis, IN. (Sponsor:
Stuart J. Warden, FACSM)
(No relationships reported)
While improvements in gait speed are commonly achieved following therapy for
individuals with stroke, many in the chronic stages still experience gait deficits,
causing declines in community ambulation. This may be associated with an inability to
sustain gait speed for an extended period of walking, yet little is known regarding gait
speed sustainability.
PurPOsE: To determine if individuals with chronic stroke have the ability to sustain
gait speed for 6 minutes of walking.
METhOds: Forty-five individuals with chronic stroke completed a 10 meter walk
test (10MWT) and 6 minute walk test (6MWT) over a gait mat. For the 10MWT,
subjects walked at the fastest pace possible that felt safe. For the 6MWT, subjects
walked at a comfortable pace for 6 minutes while traversing a 30-meter walkway,
allowing for multiple passes over the gait mat. Gait speed sustainability was measured
as the difference between the peak speed during the 6MWT and the speed at the end.
rEsuLTs: The 6MWT peak speed (0.89 m/s ±0.38) was significantly slower than the
10MWT speed (1.06 m/s ±0.51), suggesting subjects were capable of selecting a fast
pace versus one for extended walking. Yet, there was a significant gait speed reduction
of 0.07 m/s (±0.09) from peak to end (0.82 m/s ±0.36) during the 6MWT, indicating an
inability to sustain speed. These findings were most evident in Unlimited Community
Ambulators (CA) (10MWT 1.38 m/s; 6MWT peak 1.15, end 1.07), followed by
Limited CA (10MWT 0.71 m/s; 6MWT peak 0.61, end 0.55), while Household
Ambulators showed no differences (10MWT 0.34 m/s; 6MWT peak 0.30, end 0.28).
The total distance walked during the 6MWT (277.7 m ±135.5) was significantly less
than the estimated distance (320.9 m ±138.2) based on peak speed. Subjects also
displayed a significant increase in Rating of Perceived Exertion at the end (8 ±3 to 12
±4) of the 6MWT. These indicate that the declining gait speed occurred with increased
exertion and a reduction in total distance walked.
CONCLusION: Individuals with chronic stroke could not sustain their gait speed
for extended walking, which was associated with increased exertion and a reduction
in estimated total distance walked. As these differences were primarily observed in
Unlimited and Limited CA subgroups, community ambulation potential might be
incomplete without assessing gait speed sustainability.
1530 Board #122 May 30, 2:00 PM - 3:30 PM
Investigating The Walking ability Of Patients With
Parkinson’s disease Via Non-motorized Treadmills
Han-Wen Chang1 , Wen-Hsu Sung1 , Tien-Yow Chuang2 .
1 2 National Yang-Ming University, Taipei, Taiwan. Taipei Veterans
General Hospital, Taipei, Taiwan.
(No relationships reported)
Decreased walking ability of patients with Parkinson’s disease (PD) may result in the
limitations of activity of daily living. Non-motorized treadmills (NMTs) can provide
active walking training. Subjects need to exert force from lower limbs to drive the belt
forward to walk on it. Currently there are still few studies on the application of NMTs,
especially on patients with PD.
PurPOsE: The purpose of this study is to investigate the walking ability of patients
with PD and to compare the walking ability between healthy adults and the patients
with PD via NMTs.
METhOd: Six healthy adults (group A) and six patients with PD (group B) were
recruited. Group B was assessed during on-period (in 2 hours after taking medicine).
Subjects were asked to walk on the NMT at self-paced speed and at as fast as possible
speed for 1 minute respectively. We acquired the data of walking velocity, cadence,
step length, and ground reaction force (GRF, which was normalized to body weight
and conveyed to %BW). Independent sample t-test was used to analyze the data.
Statistical significance was set at level of 0.05.
rEsuLT: The mean age (y/o) (70.83±3.60 vs. 72.08±5.55; p=.654), height (cm)
(161.33±11.27 vs. 161.83±8.86; p=.934), and weight (kgw) (61.67 ±11.48 vs.
68.67±11.22; p=.311) between two groups were shown no significant difference.
At self-paced speed, parameters of group A & group B: walking velocity (m/sec) is
0.58±0.13 vs. 0.47±0.25 (p=.395); cadence (step/min) is 98.00±18.85 vs.100.50±18.76
(p=.823); step length (m) is 0.36±0.10 vs. 0.28±0.10 (p=.185); GRF (%BW) is
1.16±0.36 vs. 1.02±0.03 (p=.381). At fast speed, parameters of the two groups:
walking velocity (m/sec) is 0.86±0.12 vs. 0.60±0.31 (p=.101); cadence (step/min) is
122.00±17.66 vs. 124.50±20.50 (p=.826); step length (m) is 0.43±0.11 vs. 0.29±0.12
(p=.054); GRF (%BW) is 1.16±0.34 vs. 1.03±0.02 (p=.401). There was no significant
difference in these parameters between two groups.
CONCLusION: The parameters revealed no significant difference between groups.
However, the walking velocity of group B was slower than group A (self-paced
MEDICINE & SCIENCE IN SPORTS & EXERCISE ®
speed & as fast as possible speed: 82.32% & 69.50% respectively); step length was
decreased (76.85% & 65.77% resp.); GRF is decreased (87.94% & 88.91% resp.).
Our preliminary results may be a reference for the further NMT training on patients
with PD.
1531 Board #123 May 30, 2:00 PM - 3:30 PM
Validity of handgrip Exercise to study Vascular Function in
Parkinson’s disease
Kylene Peroutky, Brandon Pollock, Keith Burns, John
McDaniel, Angela Ridgel. Kent State University, Kent, OH.
(Sponsor: Ellen L Glickman, FACSM)
(No relationships reported)
BaCKGrOuNd: Parkinson’s disease (PD) is a degenerative disorder of the central
nervous system characterized by symptoms of motor dysfunction including tremors,
impaired gait, and rigidity. Although autonomic dysfunction impairs the regulation
of the cardiovascular system and oxidative stress may be associated with peripheral
vascular dysfunction in this population, blood flow limitations during exercise and the
extent of vascular dysfunction has yet to be established. Although handgrip exercise is
a common modality used to evaluate blood flow and vascular function during exercise,
the impaired motor control of this population may prevent from being a valid testing
modality. PUPROSE: This study was used to validate whether the PD group was
capable of performing consistent handgrip contractions over a prolonged duration and
across various intensities.
METhOds: Ten volunteers, 5 with PD and 5 controls matched for age performed a
four stage handgrip protocol. Each participant was instructed to squeeze a handgrip
dynamometer once per second for 3 minutes at 4 different intensities (30, 60, 90, and
120 N). The subjects had real-time visual feedback of the force tracings during the
entire protocol as well as a horizontal guideline which represented the target force.
rEsuLTs: Statistical analysis indicated that across the entire protocol there was
no difference in the percentage of contractions between the control (63.3±7.8%) and
PD (69.7±9.9%) groups that were within 10% of the target force. There was also no
statistical significance in the absolute error between the control (3.6±1.4 N, 5.6±0.84
N, 7.7±0.90 N, 10.8±3.4 N) and PD (2.9±0.79 N, 5.3±1.03 N, 7.2±1.5 N, 8.2±1.3
N) groups for the 4 levels of increasing intensity, respectively. In addition, although
the duration of the contraction increased from Stage 1 to Stage 4 for both groups
(approximately 298 ms to 534 ms) there was no statistical difference between the
healthy controls and PD.
CONCLusION: The results of this study indicate that the PD patients are capable
of performing the handgrip exercise to the same aptitude as the control group. This
suggests that the handgrip protocol is a valid method that can be used to evaluate
vascular health and blood flow in PD patients compared to controls.
1532 Board #124 May 30, 2:00 PM - 3:30 PM
Loading asymmetry during the sit to stand in People with
Multiples sclerosis
Bradley J. Bowser 1 , Cathleen N. Brown 2 , Lesley J. White,
FACSM 2 , Simpson J. Simpson, FACSM 2 . 1 South Dakota State
University, Brookings, SD. 2 University of Georgia, Athens, GA.
(No relationships reported)
Mediolateral (ML) postural instability for people with multiple sclerosis (MS) is
largely influenced by interlimb loading asymmetries. During quiet standing, people
with MS favor their stronger limb by shifting their center of pressure towards the
stronger leg side and simultaneously increasing the vertical ground reaction forces
(GRF) to that leg. While ML postural stability and loading asymmetries have been
examined during quiet standing, no research has examined these two variables during a
sit to stand (STS) movement.
PurPOsE: To compare ML stability and loading asymmetry between MS and non-
MS persons during a STS movement.
METhOds: Participants were divided into three groups: an MS group with leg
weakness, less than 1.4 BW on 1RM leg press (MS-LW; n = 10; 49 ± 10 yr), an MS
group with comparable strength to controls, greater than 1.4 BW on 1RM leg press
(MS-CS; n = 11; 40 ± 12 yr), and a non-MS control group (CON; n = 12; 43 ± 12 yr).
GRFs were captured bilaterally during five STS trials. ANOVAs followed by post-hoc
testing (α = 0.05) were used to determine group differences for the variables of interest
displayed in Table 1.
rEsuLTs: Significant group differences for 1RM leg press, RLA, and ML stability
were revealed (Table 1). Post-hoc comparisons indicate lower 1RM leg press and
increased ML instability for MS-LW compared to both CON and MS-CS (Table 1).
RLA was also higher in MS-LW compared to CON (Table 1).
CONCLusION: During the STS, persons with MS who have leg weakness display
greater ML instability that is likely due to greater vertical loading occurring on the
dominant/stronger limb. MS training protocols that emphasize both strength and
symmetry training may be needed in order to improve ML stability during dynamic
movements such as the STS.
ACSM May 28 - June 1, 2013 Indianapolis, Indiana