Original scientific paper
EMG AND GRF ANALYSIS OF STEP TOUCH PERFORMANCE AT DIFFERENT HEIGHTS OF STEP BENCH
Maja Horvatin-Fučkar
; Kineziološki fakultet Sveučilišta u Zagrebu, Hrvatska
Jadranka Vlašić
; Kineziološki fakultet Sveučilišta u Zagrebu, Hrvatska
Drena Trkulja-Petković
; Kineziološki fakultet Sveučilišta u Zagrebu, Hrvatska
Abstract
The main goal of this research was to establish some
predictive biomechanical performance indicators:
electromyographic activities (EMG) of leg muscles and
kinetics parameters of ground reaction force (GRF)
during dynamical movements stepping on and off at
different heights of step bench performing the step touch.
Measuring EMG signals was made by 8-channel
(TELEMG) system monitoring the dominant,
characteristic of both legs muscles: m. rectus femoris, m.
biceps (caput longum), m. gastrocnemius medialis, m.
gluteus maximus. Kinetics signals was measured by
Kistler platform for ground reaction force type 9281C,
with frequency of sampling 1000 Hz. The measuring
procedures included 9 examinees, long-time professional
step aerobics instructors. By analyzing the basic statistics
parameters from the processed EMG signals highest
energy consumption had: m. gastrocnemius medialis (L),
then m. biceps femoris (L), m. rectus femoris (R), and m
gastocnemius medialis (R). Wilcoxon matched pairs test
has proved that there are statistically significant
difference in muscle contraction intensity when
increasing the exertion intensity by increasing the height
of the step bench. The basic statistics parameters of the
ground reaction force (GRF) indicate the greatest values
in vectors Fz and Fy, as statistically significant differences
between different height of the step bench conditional
increasing the amplitude of movement and increasing the
intensity during stepping on and off at different heights of
step bench.
Keywords
electromyography (EMG); ground reaction force (GRF); step aerobics instructors
Hrčak ID:
106259
URI
Publication date:
1.7.2013.
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