The Differences of Rectus Abdominis Muscle Activation between
Volleyball and Hockey Player while Performing Abdominal Crunches
Asha Hasnimy Mohd Hashim, Mohd Shafie Abdul Rahman, Halijah Ibrahim and Zainal Abidin Zainuddin
Faculty of Education
Universiti Teknologi Malaysia
Introduction
Results
Abdominal crunches is widely known as one method of exercise to strengthen rectus
abdominus muscle. However, the effectiveness of this exercise to strengthen all subunit of rectus abdominis muscle has been questioned. It is reported that, only a part of
rectus abdominis been activated while performing abdominal crunches. This may due to
the nature of sports which require different sub-unit of rectus abdominis to activate
although performing the same task. Therefore, a research has been conducted to
identify and analyse the rectus abdominis sub-unit activation while performing
abdominal crunches between a volleyball and a hockey player.
The mean value (mV) of rectus abdominis sub-unit contraction between hockey and
volleyball players is shown in Table 1 and been translated in graph 1 for comparison.
In general, there are large differences in mean values of rectus abdominis sub-unit
contraction between hockey and volleyball players except in sub-unit right 3 and right
4.
Method
Table 1: Mean value (mV) of rectus abdominis sub-unit contraction between
hockey and volleyball players
Right 1 Right 2 Right 3 Right 4
Left 1
Left 2
Left 3
Left 4
0.1108
0.1286 0.1923 0.1519
0.1011 0.0963 0.2481 0.1944
0.2058
0.2144 0.1934 0.1552
0.2551 0.2278 0.1860 0.1260
Subjects: Chosen from university’s volleyball and hockey team.
Procedure: Subjects are required to perform abdominal crunches (lie on back with knee
bend, lift shoulders off the floor, concentrating on moving ribs towards hips. Hands on
chest. Go slow and keep breathing - 2 seconds up, hold for 2 seconds, then 2 seconds
going down.). While performing abdominal crunches, subjects are required to wear
electrode on their rectus abdominis (divided into 8 sub-unit). The rectus abdominis subunit activation were recorded using Biopac Student Lab: (Electromyography) software
and was analysed using Statistical Packages for Social Science version 14.0 (SPSS
14.0).
Hockey
Volleyball
Graph 1: Mean value (mV) of rectus abdominis sub-unit contraction between
hockey and volleyball players
Figure 1: Illustration on performing abdominal crunches
However, T-test analysis shows that there are significant differences in all rectus
abdominis sub-unit activation while performing abdominal crunches (right1, t= 179.507, p=0.000; right 2, t= -110.299, p=0.000; right 4, t= -3.058, p=0.007; left
1, t= -181.037; p=0.000; left 2, t= -162.662, p=0.000; left 3, t= -48.997, p= 0.000
and left 4, t= -75.264, p= 0.000) between hockey and volleyball player except for
sub-unit right 3, t= -1.199; p=0.246.
Regardless to the type of sports, it is shown that the right side of rectus
abdominis is less activated compared to left side, where left 1 and left 3 are more
activated when compared to the other two (right 1 – left 1, t= -2.918, p =0.009;
right 2 – left 2, t=1.799, p=0.088; right 3 – left 3, t= -3.319, p=0.004 and right 4 –
left 4, t= -0.809, p= 0.429).
Discussion
Figure 2: Subunit of muscle activitation
Figure 2: EMG wave during muscle contraction
Other researchers have noted differences in muscle activity between the upper
and lower halves of the rectus abdominis while performing specific abdominal
exercises (Basmajian & Deluca, 1985). This is attributed to the fact that the other
studies divided the muscle in half and compared the electrical activity between
the upper and lower halves while we divided the muscle into its anatomical units
and compared the electrical activity across quadrants.
The present study found that right and left side of rectus abdominis are activated
differently and it contradicts the findings Furlani & Bankoff (1987) and Piering et.
al. (1993). This may due to the nature of sports or human habit that tends to
activate only one side of body or certain unit of muscles compared to the other.
For example, a hockey player tends to flex their trunk on the right side of body
meanwhile for volleyball player repetitive trunk flexion and extension is the
nature of the game. Thus it shown that abdominal crunches exercise alone will
not activate all sub-unit of the rectus abdominis and therefore, other abdominal
exercises are needed to activate other rectus abdominis sub-unit.
References
Basmajian, J.V. and Deluca, C.J. (1985). Muscles Alive: Their Functions Revealed by Electromyography. Williams & Wilkins: Baltimore.
Furlani J. and Bankoff A.D. (1987) Electromyographic analysis of the rectus abdominis and external oblique muscles during exercises in lateral decubence. sitting and kneeling
positions. Electromyography Clinical Neurophysiology, 7(27), 265-272.
Piering, A.W., Janowski, A.P., Moore,M.T, Snyder,A.C. and Wehrenberg, W.B. (1993). Electromyographic analysis of four popular abdominal exercises. Journal of Athletic
Training, 28 (2), 120-126.
Sternlicht E., Rugg, S.G., Bernstein, M.D. and Armstrong, S.D. (2005). Electromyographical analysis and comparison of selected abdominal training devices with a traditional
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