The International Paralympic Committee required the development of a new
evidence-based classification system, by developing measures of performance
and measures of impairment. In cross-country (XC) sit skiing, athletes compete
sitting on a ski-ski and generate propulsion with upper limbs and, when
possible, trunk movements. The purpose of this thesis was to develop a
measure of performance and a measure of impairment of trunk that can be used
for classification purposes. Firstly, biomechanics (maximal speed, generated
force, cycle characteristics, and muscle activation) of skiing on snow and on an
ergometer was compared (article I). The assessment of biomechanics and of
trunk kinematics on the ergometer was used to develop a measure of
performance (article III). Secondly, trunk kinematics during balance test
performed with personal sit-ski was used to propose a measure of impairment
(article II). During the process, a need for a new specific testing device was
identified. A new mecha
nical system was designed to quantify trunk
kinematics and strength respectively during balance and strength tests.
Collected results allowed developing a measure of trunk impairment that can
be used for classification purposes (article IV). A total of 24 elite XC sit skiers
were recruited. Two separate investigations were completed during the World
Cup: (1) performance tests were conducted on snow and in a laboratory
(articles I, III) and balance tests with personal sit-ski were performed in the
laboratory (article II); (2) strength and balance tests with the new testing device
were performed in the laboratory (article IV). In addition, a cluster analysis was
applied to divide athletes according to their performance and impairment and
to identify the minimum set of parameters that allowed for athletes’ clustering.
Pushing cycle results showed that generated force or maximal speed, together
with cycle time, trunk maximal backward inclination, and trunk range of
motion allowed clustering athletes according to their performance (articles I, III).
Results of balance test and strength test respectively showed that trunk range of
motion and generated force with and without a backrest allowed clustering
athletes according to their impairment (articles II, IV). In conclusion, the
proposed tests and the identified set of parameters may be considered for the
XC sit skiing new evidence-based classification system.
Keywords: performance, adapted ergometer, impairment, strength, trunk
control, spinal cord injury
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