2007 Bateman, Thomas D by wfq74180


									                          Bateman, Thomas D.
    A biomechanical evaluation of a novel mobile walking device
                     Faculty Mentor: Matthew K. Seeley, Exercise Sciences

 Many individuals rely on crutches to help them walk. Those relying on
traditional crutches often suffer from upper-extremity pathologies as well as
psychological detriments. 1 Additionally, those using crutches typically suffer
from increased energy expenditures during locomotion. 2 The Millennial
Crutch (Figure 1) is a proposed alternative to the traditional crutch. The
producers of the Millennial Crutch purport that Millennial Crutch use
eliminates many of the disadvantages of traditional crutch use.

The purpose of the research is to quantify and compare the energy that is
transferred from crutch to patient during the stance phase of locomotion in
patients using the traditional crutch and Millennial Crutch. Stance is defined
as the time in which the crutch is in direct contact with the ground. It has
been hypothesized that the Millennial Crutch will absorb more energy during
the first half of stance, and transfer more energy to the patient during the
second half of stance, in comparison to the traditional crutch.

Data collection involved ten males and ten females. Thirty-five small reflective markers were
placed on various anatomical landmarks, using adhesive tape, to facilitate 3-D motion analysis of
the entire body via high-speed video. After the reflective markers were applied, the participants
began the ambulation trials. Participants were required to complete five successful trials while
using the traditional crutch and five successful trials while using the Millennial Crutch. Each trial
was considered successful if: 1) the ambulation was subjectively considered representative by the
researcher and participant, and 2) the ambulation occurred within ± 2.5% of a pre-determined
standardized ambulation velocity. The order in which each crutch is utilized was randomized.
Video data was collected using high-speed video cameras.

The 3-D location of each body segment center of mass was derived from the spatial location of
each reflective marker. Next, the spatial location of the whole-body center of mass was derived
from the 3-D location of each body segment. Horizontal velocity, necessary for the
quantification of kinetic energy, of the whole-body center of mass was derived from the
aforementioned position data; this velocity was used to estimate the amount of kinetic energy
transferred to and from the body during stance. Vertical displacement of the whole-body center
of mass, necessary for the calculation of potential energy, was measured using similar means.

This study used one independent variable, comprised of two conditions: 1) traditional crutch
ambulation, and 2) Millennial Crutch ambulation. The two conditions were used to manipulate
three dependent variables: 1) change in kinetic energy during the second half of the stance phase;
2) change in kinetic energy during the first half of the stance phase; and 3) the total vertical
displacement of the center of mass during the entire stance phase (potential energy). The within-
subjects design required each participant to perform each condition. A multivariate statistic was
used to quantify the influence of the independent variable on the group of dependent variables (p
= 0.05). A paired t-test was used to examine the effect of the two conditions on each of the
dependent variables. The significance level (p = 0.05) for each of these post hoc comparisons
was adjusted using the false discovery rate procedure.3 We were able to determine that there was
a significant difference between the traditional crutch and the Millennial Crutch.

Although it is concluded that the Millennial Crutch does significantly decrease energy
expenditure during ambulation, there are other facets of the crutch that can be researched. It has
also been hypothesized that the angle and ergonomics of the hand grip provide decreased palmer
loading resulting in less wrist injuries. Data collection and analysis methods for this hypothesis
are currently being discussed.

The main problem that we faced was using the computer tracking system properly. It was new to
the college and took quite a bit of time to get familiar enough with it to collect and analyze data.
After comprehending what the program was doing, data collection was considerably easier and
more accurate.

This experience in research has been very valuable to me. I never realized all the details that had
to be considered and precautions taken to avoid inaccurate data. My future plans involve a
professional career that could very well incorporate daily research opportunities. This project has
helped me understand a little of what would be required if I chose to pursue that route in my
professional career. I would like to acknowledge the help of my mentor, Dr. Matthew Seeley,
and all of my colleagues involved in the research.4

1. Shortell, D. (2001). The design of a compliant composite crutch. Journal of Rehabilitation
   Research and Development, 38(1), 23-32.
2. Sala, D. (1998). Crutch Handle Design: Effect on Palmar Loads During Ambulation.
   Archives of Physical Medicine and Rehabilitation, 79(11), 1473-6.
3. Benjamini, Y. & Hochberg, Y. (1995). Controlling the false discovery rate: A practical and
   powerful approach to multiple testing. Journal of the Royal Statistical Society B, 57(1), 289-
4. Adam Roggia, Emily Stephens, Matthew Francis.

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