Biomechanics and Medicine in Swimming XI

legs than they could float motionless on their front or back. Despite
Harrod’s findings, the Red Cross never did introduce gliding skills prior
to floating in their learn-to-swim program (American Red Cross, 1992).
At least with adults, it appears that floating probably can be taught prior
to introducing the gliding skills. Interestingly, the two gliding skill items
were as difficult for the current sample to perform as were the elementary
backstroke and sidestroke. This difficulty is somewhat surprising
since both front and back gliding nominally would appear to be much
less complicated and difficult items than the two resting strokes.
Based upon these results, the authors could not suggest to the American
Red Cross that there was any evidence-based support to alter the
order in which the thirteen selected skill items ought to be presented
in the revised 2009 American Red Cross learn-to-swim program. The
study obviously did not test all pertinent skill items involved in the Red
Cross’ learn-to-swim program and therefore the results should not be
interpreted to apply to the validity of the order for skills in the entire
learn-to-swim program. Because the current sample was limited to a relatively
small convenience sample of normally-abled young adult college
students, it also is not possible to suggest that even the order of these
items with the strong coefficient of reproducibility actually applies to
other individuals such as preschool or elementary-age children or to individuals
who may be differently-abled. Samples drawn from other specific
populations would be required to understand whether this order of
acquisition, and by extension, instructional order, should be considered
to be universal or whether the order is unique to different age and ability
groups. Understanding how much variability in order is associated with
different ages and ability groups would be crucial pieces of information
to support future evidence-based revisions to learn-to-swim programs
such as the American Red Cross.
The study and its results have some very definite limitations. A sample
size of thirty-one was relatively small which limited the statistical
power with which the descriptive scalogram could identify variability
in the order of item difficulty. We initially had intended to test all sixty
class participants, but some students did not volunteer while others were
absent some days and did not complete all items. The sample was definitely
a convenience sample which meant that some of the less skilled
individuals opted not to participate, skewing the participant skill levels
as evidenced by the high average number of successful item completions.
A scalogram relies upon testing a truly heterogeneous sample that
should include persons who are capable of passing few if any of the
items. The current sample of young adults was definitely skewed toward
a more homogeneous and skilled sample which is not surprising given
that they were recruited from instructional swimming classes of college
students.
Because the testing occurred during the middle instead of the beginning
of the semester of study, it is probable that previous instruction
biased the sample toward greater skillfulness. It also appears that the
individual swim instructor who was an assistant swim coach emphasized
learning and practice of the competitive swim strokes of front and back
crawl, breaststroke, and butterfly and not resting strokes of elementary
backstroke and sidestroke. Presumably this explains the lower success
rate observed in performance of the elementary backstroke and sidestroke
items. Many students appeared puzzled and had never heard of
these two strokes when presented with them as test items in the study.
The instructional bias also presents a challenge to the potential utility
of the scalogram and interpretation of the robustness of the coefficient
of reproducibility. It was generally presumed by Guttman (1950)
that item difficulty possessed some inherently invariant task qualities
and characteristics not substantively influenced by intervention and instruction.
In the current sample, it appeared fairly clear that familiarity
with competitive strokes and lack of familiarity with resting strokes
influenced the degree of success demonstrated by some participants.
This definitely could have influenced the order of item acquisition. The
authors have personal instructional experience that both the elementary
backstroke and sidestroke can be effectively introduced prior to front
chaPter5.education,adviceandBiofeedBack
and back crawl strokes. The current results tend to negate those personal
observations.
The observation of potential instruction or intervention bias means
that further studies using a scalogram should be conducted under experimental
conditions. Samples with well defined differences in experiences
and instruction need to be compared to clarify the degree to which the
coefficient of reproducibility is altered. For example if the first author
and the assistant coach instructor of the classes in the current study
both taught similar groups of young adults, one emphasizing acquisition
of resting strokes and the other focusing on the competitive strokes,
would different orders and coefficients of reproducibility result? There
are definitely pedagogical and methodological questions that should and
could be addressed.
conclusIon
The current study employed Guttman’s (1950) descriptive scalogram
technique to examine the validity of swim skill item order of acquisition
in a small convenience sample of young adults. The instructional order of
thirteen swimming skills used by the 2004 American Red Cross learnto-swim
program was tested using a scalogram. The Red Cross order
of the thirteen swimming items produced a very strong coefficient of
reproducibility (CR = 0.93) and provided some evidence-based support
for the Red Cross to continue presenting those swimming items in a
similar order in their learn-to-swim programs. The results of the study
revealed several limitations in the conduct of the study (e.g., relatively
small convenience sample, limited skill and age range of participants) as
well as raised questions about the robustness of the scalogram technique
itself and the interpretation of the coefficient of reproducibility. The authors
have proposed several subsequent studies to clarify the technique
and interpretation of the results.
reFerences
American National Red Cross. (1981). Swimming and aquatics safety.
Washington, D.C.
American Red Cross. (1992). Water Safety Instructor Manual. St. Louis:
Mosby Year Book.
American Red Cross. (2004). Water Safety Instructor’s Manual. Yardley,
PA: StayWell.
American Red Cross. (2009). Water Safety Instructor’s Manual (r.09).
Yardley, PA: StayWell.
Darwin, C. (1877, July). A biographical sketch of an infant. Mind, 285-
294.
DeOreo, K. (1976). Dynamic balance in preschool children: Quantifying
qualitative data. Research Quarterly, 47, 526-531.
Erbaugh, S.J. (1978). Assessment of swimming performance of preschool
children. Perceptual and Motor Skills, 47, 1179-1182.
Erbaugh, S. (1980). The development of swimming skills of preschool
children. In C. Nadeau, K. Newell, G. Roberts, & W. Halliwell (Eds.),
Psychology of motor behavior and sport-1979 (pp. 324-335). Champaign,
IL: Human Kinetics.
Gesell, A. (1940). The first five years of life. New York: Harper and Row.
Guttman, L.L. (1950). The basis for scalogram analysis. In S.A. Stouffer,
L. Guttman, E. Suchman, P. Lazerfeld, S. Star, & J. Clausen (Eds.),
Measurement and prediction (pp. 60-90). Princeton, NJ: Princeton
University Press.
Harrod, D. (1990). A scalogram analysis of the American Red Cross Beginner
swimming skill items. Unpublished Master’s thesis, Kent State
University, Kent, OH.
Harrod, D., & Langendorfer, S.J. (1991). A scalogram analysis of American
Red Cross Beginner swimming skill items. National Aquatics
Journal, 6, 10-16.
Haywood, K.M., & Getchell, N. (2009). LifeSpan Motor Development
(5 th Ed.). Champaign, IL: Human Kinetics.
Herkowitz, J. (1978). Developmental task analysis: The design of movement
experiences and evaluation of motor development status. In
335