european college of sport science

MUSCLE ACTIVITY DOES NOT CHANGE IN RESPONSE TO DIFFERENT LOADS DURING BENCH PRESS
KIN ISLER, A., ASCI, A., ARITAN, S.
1. BASKENT UNIVERSITY, 2. HACETTEPE UNIVERSITY
PP-BM05 Biomechanics 5
Introduction: Among the exercises used in heavy-resistance training programs, bench press is one of the most popular upper body lifts.
Myoelectrical activity of upper-body muscles during bench press exercise has attracted a great deal of interest (Clemons & Aaron, 1997;
Welsch et al. 2005) however limited research have been found related with the effects of different loads on electromyographical activity of
upper body muscles during the bench press. Therefore the aim of this study was to determine if muscle activation changes in response to
different loads during non-bar release concentric bench press motion.
Methods: Seventeen male handball players volunteered to participate in this study. Subjects performed five explosive non-bar release
concentric bench press motions at 50, 60, 70, 80 and 100 % of their 1-RM at 200 % of their biacromial distance (BAD). The EMG activity of
clavicular pectoralis major (CPM), sternocostal pectoralis major (SPM), anterior deltoid (AD) and triceps muscles of dominant side were
recorded by using surface electrodes. For each muscle at each different loads, root mean squares of EMG signals were calculated spontaneously
from the beginning of the lift until the maximum force formation and all root mean squares values were summed to get a total
muscle activation value. Maximum force for each lift at different loads was calculated by inverse dynamics Methods: Results: Results of
one way ANOVA with repeated measures did not indicate any significant differences in muscle activation at different loads in non-bar
release concentric bench press motion (p>.05).
Discussion: The present study suggested that different loads did not result in differences in muscles’ activation patterns during non-bar
release concentric bench press motion at 200 % BAD. This implicates that CPM, SPM, AD and triceps muscles are similarly activated
during the bench press at different loads.
References
Clemons JM, Aaron C. (1997) J Strength and Cond Res, 11(2), 82-87.
Welsch AE, Bird M, Mayhew JL (2005) J Strength and Cond Res, 19 (2), 449-452
MUSCLE ACTIVATION AND LOADING OF THE SHOULDER JOINT IN HUMERAL EXTERNAL ROTATION BY PULLEY AND
VARIABLE RESISTANCE
PELTONEN, H., AROKOSKI, J., KALLINEN, M., PULLINEN, T.
UNIVERSITY OF JYVÄSKYLÄ
Introduction: Free weights, such as dumbbells and rubber bands and cable pulley devices are traditionally used for rehabilitation of
shoulder disorders (Reinhold et al. 2007). Also the weight of the arm itself has been used as resistance. The aim of the study was to
evaluate the differences in the loading of the muscles and the glenohumeral joint between a cable pulley machine (CP) and variable
resistance machine (VR) during axial humeral external rotation.
Methods: Eleven healthy male subjects took part in the study. Intramuscular electromyography from five muscles of the shoulder (medial
and posterior parts of deltoideus, supraspinatus, upper part of trapezius and infraspinatus), torque and power output were measured
with different rotation angles and different loads (10%, 50% and 100% of 1RM). Also the compressive and shear force in the glenohumeral
joint was analysed (Harms-Ringdahl et al. 1985) at the horizontal level at particular angles of rotation. External rotation was self-paced
and performed in the scapular plane.
Results: The range of the movement (ROM) when using the CP reduced compared to the VR along with the increasing workload (P