Basic Science Poster Template

1
ABSTRACT
Figure 1. (A) Activity counts during walking (N
10) (means SE )(B) Activity counts during
running (means SE) (N10) (C) Energy
expenditure predicted from Actigraph GT1M-V3
activity counts using the ACSM equation and two
popular accelerometer regression equations.
METHODS

• Accelerometers
• Actigraph AM7164
• 37.8 gms, 5.1 x 4.1 x 1.5 cm
• Actgraph GT1M-V1
• 40.2 g, 5.1 x 4.1 x 1.8 cm
• Actigraph GT1M-V2 and GT1M-V3
• 26.7 g, 4.0 x 3.9 x 1.8cm
• Participants
• 10 Trained runners
• Average Age 23.6 2.8 yrs
• Able to run 1 mile under 5 min
• Treadmill Protocol
• Two trials, each consisting of
• Walking- 3, 5, and 7 km.hr-1
• Running- 8, 10, 12, 14, 16, 18, and 20 km.hr-1
• Speed monitored using a tachometer
• Duration of each stage- 3 min

Motion sensors from Actigraph are the most
commonly used accelerometers in physical activity
research. Currently, researchers can use the 7164
or one of three different versions of the GT1M to
objectively measure physical activity. Purpose
To determine if differences exist between outputs
from the 7164 and the three versions of the GT1M
at a given walking or running speed. Methods Ten
male participants (23.6 2.8 yrs) completed
treadmill walking and running at ten different
speeds (3-minute stages) while wearing either the
7164 and the latest GT1M (GT1M-V3) or GT1M
version one (GT1M-V1) and GT1M version two
(GT1M-V2). Participants walked at 3, 5, and 7
km.hr-1 followed by running at 8, 10, 12, 14, 16,
18, and 20 km.hr-1. The accelerometers were worn
on the left and right anterior axillary lines at
the waist. Testing was performed on different
days using a counterbalanced within-subjects
design to account for potential differences
attributable to accelerometer placement. One-way
repeated measures ANOVA at each speed followed by
post-hoc pairwise comparisons with Bonferroni
corrections as necessary were used to examine
differences between the four accelerometers.
Results There were no significant differences
between activity counts from the four
accelerometers at any given walking or running
speed (plt0.05). At all running speeds, activity
counts from the 7164 and GT1M-V2 displayed the
lowest and highest counts.min-1 (cpm),
respectively. Output from all accelerometers
peaked at 14 km.hr-1 (mean range 8974 677 to
9412 982 cpm) and then gradually declined with
increasing speed. The mean difference score at
peak output between the 7164 and GT1M-V2 was 439
565 cpm. Conclusions There were no
statistically significant differences between
outputs from all the accelerometers. Researchers
can select any of the four Actigraph
accelerometer during research.

(A)
(B)
INTRODUCTION

• Physical activity monitors that sense body
  accelerations, also known as accelerometers are
  often used to measure physical activity and
  energy expenditure.
• Monitors manufactured by Actigraph (Fort Walton
  Beach, Florida) are the most commonly used
  accelerometers in physical activity research.
• As a result of repeated modifications by
  Actigraph, currently there are 2 different models
  (7164 and GT1M) and 3 different versions of the
  GT1M being used in research today.
• Most energy expenditure equations and cut-points
  denoting light, moderate, and vigorous physical
  activity have been derived using the 7164
• Actigraph says that only a negligible difference
  in activity counts may exist while comparing
  inter-model or inter-version activity counts
• However, studies comparing activity counts from
  the 7164 and the GT1M have shown varying results
• It has not been established that activity counts
  from the three versions of the GT1M are
  comparable to each other and to those from the
  7164.

(C)
RESULTS

• Statistical analysis revealed no significant
  differences between devices (plt0.05)
• During walking activity counts increased
  linearly
• Maximum mean difference at 5 km.hr-1 (179 400
  cpm) between GT1M-V1 and GT1M-V2
• During running
• Curvilinear increase in activity counts
• Peak at 14 km.hr-1
• Curvilinear decrease in activity counts
• Maximum mean difference at 18 km.hr-1 (680 628
  cpm) between 7164 and GT1M-V2

CONCLUSIONS

Inverted-U-Phenemenon

• Researchers can use any of the above mentioned
  Actigraph accelerometers in a single study.
• Direct comparisons can be made with other
  investigations that used one or all of these
  devices.
• Actigraph monitors demonstrate an
  Inverted-U-phenomenon with increasing running
  speed.
• Hence, researches must be careful when estimating
  energy expenditure at speeds gt10 km.hr-1

PURPOSE
The purpose of our study was to determine if
activity counts obtained from the 7164, and the
three versions of the GT1M during various walking
and running speeds were different from each other.