Force, Power, and Velocity during Bench Press Movement ... - myotest

Force, Power, and Velocity during
Bench Press Movement on Stable
and Unstable Base
Hiroshima University Graduate School
Sentaro Koshida, Yukio Urabe, Koji Miyashita, Kosuke Tanaka,
and Aya Kagimori
Department of Sport Rehabilitation

Question about Conventional Strength Training
Conventional strength training may not always
improve the sports performance
Actual Sports Movement
Strength Training
The strength training may not require stabilizing
the body during movements

Importance of Trunk Stability during Movements
Trunk muscle activation initiates before upper arm
movements Aruin and Latash 1995; Hodge, et al. 1997
Trunk stability is an important component for force
production on upper body in sports performance

Trunk Activity on Unstable Base
Trunk EMG activity was significantlyincreased on unstable
base
Vera-Garcia et al. 2000;
Anderson and Behm 2003
Conventional strength training may not improve
neuromuscular control of trunk during movements

Applicability of Strength Training on Unstable Base
Isometric force maneuver on unstable condition was
decreased by 60% during the chest press
Anderson and Behm 2003
Effect of unstable base on force, power, velocity
during dynamic upper-body movement is unclear

Objective
To compare force, power, and velocity during
bench press movement between stable and
unstable base
Clinical Significance
The result will provide us scientific foundation on
applicability of the strength training on unstable
base for the improvement of sports performance

P articipants
20 Competitive male athletes with experience in
resistance training 1year-5years
Age (year)
Height cm
Body Weight kg
1RM kg
Mean ± SD
021.3±01.5
167.7±07.7
075.9±17.5
080.1±21.1
No complaint or pain was reported during the testing

Instrumentation
Mono-AxisAccelerometer
Myotest ® , Acceltec, Inc., Switzerland
Attached to the center of
the barbell shaft
Sampling rate: 500Hz
Myotest®

Testing Protocol and Data Analysis
Test: Three sets of Single Bench press movement
at maximum efforts
Starting position:2-3 cm above the chest
Load: 50%RM
Flat BaseB Swiss Ball Base
SB
Statisticalanalysis: Paired-t test was performed to compare
maximum force, power,and velocity (p

Results
Maximum force output
N
800
700
594.6±150.8
559.9±148.0
600
500
0
400
FB
SB
N=20
p

Discussion
The maximum force, power, velocity were
significantly decreased on the unstable base
compared to the stable base
Unstable condition negatively affected on the
force performance during the dynamic movement

Discussion Cont’
Current study
The maximum force, power, and velocity were
decreased by approximately 10%
Previous studies
Isometric force maneuver on unstable condition was
decreased by 60% during the chest press
Anderson and Behm 2003

Future orientation of the research
Trunk stability and EMG activity need to be
quantified during the movement
Short and long term effect of strength training on
unstable surface need to be investigated

Summary
Force, power, and velocity were measured
during bench press movement on stable and
unstable base
Maximum force, power, and velocity were
significantly decreased by less than 10% on the
unstable base compared to the stable base