The objective of this work was to study the influence of movement strategy on fatigue
of elbow flexors during repeated flexion-extension cycles in order to enlighten the
fatigue process occurring during “pumping” in boardsailing. This dynamic exercise
was performed by six high-level Olympic boardsailors according to two movement strategies
with different amplitude and frequency. The parameters of the exercise were chosen
to result in similar mechanical work at every instant for both modalities. Isometric
evaluation was performed before and after dynamic exercise to quantify muscle fatigue.
Analysis of physical parameters (maximum voluntary contraction, endurance time) and
electromyographic parameters (in both temporal and frequency domains) emphasized the
peripheral origin of muscle fatigue at the level of the biceps brachii and the brachioradialis.
After considering the limitations of this type of study, the results are discussed
in terms of synergy and differentiation between muscles, peripheral fatigue and movement
strategy. Although the mechanical work and total physiological demands were similar
for the two movement modalities, analysis of electromyographic parameters suggests
that muscle fatigue mainly involves the biceps brachii when movements were slow and
wide, and the brachioradialis when they were rapid and short. This study makes it
possible to take these specificities into account in order to adjust the physical
training program.
Dynamic exercise, isometric evaluation, surface EMG, biceps brachii, brachioradialis.
