The electromyographic (EMC) activity of seven muscles of the trunk and lower extremity
in five male masters level ski racers during a slalom turn in both alpine skiing and
in-line skating was recorded using a telemetry system. Measurements were made on separate
testing days using slopes commonly used in each activity (24 slope alpine skiing,
5 in-line skating). Qualitative video recorded at 60 Hz was analyzed to partition
the turning cycle in both slalom skiing and in-line skating into initiation and turning
phases. The EMC data from each turning cycle were normalized to standard isometric
contractions (SIC's) for each muscle in order to quantitatively compare the amplitude
characteristics of each phase of the turning cycle in both slalom skiing and in-line
skating. The turning phase of in-line skating was found to be significantly longer
(55 %) than in slalom skiing, most likely due to significantly lower subject velocities
recorded during in-line skating (8.5 m/s vs 10.2 m/s). All muscles were active at
moderate to high levels (48 - 172 % of SIC) during each phase of the turning cycle
in both slalom skiing and in-line skating. The EMC amplitude characteristics were
similar for six of the muscles in both slalom skiing and inline skating for each of
the turning phases. Only the erector spinae displayed significantly higher average
and peak amplitudes in slalom skiing for both phases. It is concluded that the muscle
activity patterns associated with the slalom turn of in-line skating are similar but
notably more quasi-static than in slalom skiing.
Key words
Electromyography - dry-land training - in-line skating - slalom skiing
