european college of sport science

OP-ST09 Sports 9
RESPONSES TO FOUR ECCENTRIC EXERCISE BOUTS OF THE ELBOW FLEXORS PERFORMED EVERY FOUR WEEKS
NOSAKA, K., CHEN, T.C., CHEN, H.L., LIN, M.R., WU, C.J.
EDITH COWAN UNIVERSITY
INTRODUCTION: An initial eccentric exercise confers protective adaptation to a subsequent bout of the same or more demanding eccentric
exercise, which is known as the repeated bout effect. Although many studies exist concerning the repeated bout effect, most of them
investigated the effect based on two bouts of eccentric exercise. Only two previous studies (1,2) examined the repeated bout effect of
more than three eccentric exercise bouts, but the repeated bouts were performed before full recovery from the initial bout. It is not clear
what happens if the same exercise is repeated more than three times after a full recovery. This study compared responses to four bouts
of maximal eccentric exercise performed every 4 weeks to examine if additional protective adaptation is induced by the additional bouts.
METHODS: Fifteen untrained men (21.8 ± 1.9 yrs) performed four bouts of 30 maximal isokinetic (90°/s) eccentric contractions of the elbow
flexors for the range of 90° by the non-dominant arm every 4 weeks. Measurements of maximal isometric and concentric isokinetic
strength, optimum angle (OA), range of motion (ROM), upper arm circumference, plasma creatine kinase and lactate dehydrogenase
activities, myoglobin concentration, muscle soreness, and B-mode ultrasound images were taken before, immediately after and for 5
days following each bout. Changes in the variables over time were compared amongst the four exercise bouts by a two-way (bouts x
time) repeated measures ANOVA with a Scheffé’s post-hoc test. A significant level was set at P