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Muscle Function Obtained with Motion Mode Ultrasound and Surface Electromyography during Core Endurance Exercise
Published on: August 25, 2022
Trunk muscle activation during dynamic weight-training exercises and isometric instability activities
Nicolle Hamlyn1, David G Behm, Warren B Young
1School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.
Journal of Strength and Conditioning Research
|December 14, 2007
Summary
High-intensity resistance exercises like squats and deadlifts significantly activate trunk muscles more than instability exercises. This suggests traditional weight training may be sufficient for core stability, potentially negating the need for added instability devices.
Area of Science:
- Biomechanics and Exercise Physiology
- Muscle Activation Studies
- Strength and Conditioning Research
Background:
- Core stability training is crucial for athletic performance and injury prevention.
- The effectiveness of instability exercises for augmenting trunk muscle activation is debated.
- Understanding muscle activation patterns during different resistance exercises is essential for program design.
Purpose of the Study:
- To compare trunk muscle activation during dynamic weight-training versus isometric instability exercises.
- To quantify electromyographic (EMG) activity in specific trunk muscles (lower abdominals, obliques, erector spinae).
- To determine if instability exercises offer superior core activation compared to traditional resistance exercises.
Main Methods:
- Sixteen subjects performed squats and deadlifts at 80% of 1 repetition maximum (1RM) and with body weight.
- Subjects also performed two instability exercises: superman and sidebridge.
- EMG activity was recorded from lower abdominals (LA), external obliques (EO), upper lumbar erector spinae (ULES), and lumbar-sacral erector spinae (LSES).
Main Results:
- Lumbar-sacral erector spinae (LSES) EMG activity was significantly higher during 80% 1RM squats compared to 80% 1RM deadlifts.
- Both 80% 1RM squat and deadlift exercises elicited greater LSES and upper lumbar erector spinae (ULES) activation than body weight exercises and instability exercises.
- No significant differences in external oblique (EO) or lower abdominal (LA) muscle activation were observed across exercises.
Conclusions:
- High-load dynamic exercises (80% 1RM squat and deadlift) provide superior activation of the lumbar erector spinae muscles compared to body weight or instability exercises.
- Traditional resistance exercises like squats and deadlifts may be sufficient for developing trunk muscle strength and stability.
- Adding instability devices may not be necessary to augment core stability training when performing effective dynamic resistance exercises.
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