Trunk muscle activation during dynamic weight-training exercises and isometric instability activities
- Hamlyn, Nicole, Behm, David, Young, Warren
- Authors: Hamlyn, Nicole , Behm, David , Young, Warren
- Date: 2007
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 21, no. 4 (2007), p. 1108-1112
- Full Text:
- Reviewed:
- Description: The purpose of this study was to examine the extent of activation in various trunk muscles during dynamic weight-training and isometric instability exercises. Sixteen subjects performed squats and deadlifts with 80% 1 repetition maximum (IRM), as well as with body weight as resistance and 2 unstable calisthenic-type exercises (superman and sidebridge). Electromyographic (EMG) activity was measured from the lower abdominals (LA), external obliques (EO), upper lumbar erector spinae (ULES), and lumbar-sacral erector spinae (LSES) muscle groups. Results indicated that the LSES EMG activity during the 80% IRM squat significantly exceeded 80% IRM deadlift LSES EMG activity by 34.5%. The LSES EMG activity of the 80% IRM squat also exceeded the body weight squat, deadlift, superman, and sidebridge by 56, 56.6, 65.5, and 53.1%, respectively. The 80% IRM deadlift ULES EMG activity significantly exceeded the 80% IRM squat exercise by 12.9%. In addition, the 80% IRM deadlift ULES EMG activity also exceeded the body weight squat, deadlift, superman, and sidebridge exercises by 66.7, 65.5, 69.3, and 68.6%, respectively. There were no significant changes in EO or LA activity. Therefore, the augmented activity of the LSES and ULES during 80% IRM squat and deadlift resistance exercises exceeded the activation levels achieved with the same exercises performed with body weight and selected instability exercises. Individuals performing upright, resisted, dynamic exercises can achieve high trunk muscle activation and thus may not need to add instability device exercises to augment core stability training. © 2007 National Strength & Conditioning Association.
- Description: C1
- Description: 2003005669
- Authors: Hamlyn, Nicole , Behm, David , Young, Warren
- Date: 2007
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 21, no. 4 (2007), p. 1108-1112
- Full Text:
- Reviewed:
- Description: The purpose of this study was to examine the extent of activation in various trunk muscles during dynamic weight-training and isometric instability exercises. Sixteen subjects performed squats and deadlifts with 80% 1 repetition maximum (IRM), as well as with body weight as resistance and 2 unstable calisthenic-type exercises (superman and sidebridge). Electromyographic (EMG) activity was measured from the lower abdominals (LA), external obliques (EO), upper lumbar erector spinae (ULES), and lumbar-sacral erector spinae (LSES) muscle groups. Results indicated that the LSES EMG activity during the 80% IRM squat significantly exceeded 80% IRM deadlift LSES EMG activity by 34.5%. The LSES EMG activity of the 80% IRM squat also exceeded the body weight squat, deadlift, superman, and sidebridge by 56, 56.6, 65.5, and 53.1%, respectively. The 80% IRM deadlift ULES EMG activity significantly exceeded the 80% IRM squat exercise by 12.9%. In addition, the 80% IRM deadlift ULES EMG activity also exceeded the body weight squat, deadlift, superman, and sidebridge exercises by 66.7, 65.5, 69.3, and 68.6%, respectively. There were no significant changes in EO or LA activity. Therefore, the augmented activity of the LSES and ULES during 80% IRM squat and deadlift resistance exercises exceeded the activation levels achieved with the same exercises performed with body weight and selected instability exercises. Individuals performing upright, resisted, dynamic exercises can achieve high trunk muscle activation and thus may not need to add instability device exercises to augment core stability training. © 2007 National Strength & Conditioning Association.
- Description: C1
- Description: 2003005669
Trunk muscle electromyographic activity with unstable and unilateral exercises
- Behm, David, Leonard, Allison, Young, Warren, Bonsey, Andrew, MacKinnon, Scott N.
- Authors: Behm, David , Leonard, Allison , Young, Warren , Bonsey, Andrew , MacKinnon, Scott N.
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 19, no. 1 (2005), p. 193-201
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- Reviewed:
- Description: The purpose of this cross-sectional study was to evaluate the effect of unstable and unilateral resistance exercises on trunk muscle activation. Eleven subjects (6 men and 5 women) between 20 and 45 years of age participated. Six trunk exercises, as well as unilateral and bilateral shoulder and chest presses against resistance, were performed on stable (bench) and unstable (Swiss ball) bases. Electromyographic activity of the upper lumbar, lumbosacral erector spinae, and lower-abdominal muscles were monitored. Instability generated greater activation of the lower-abdominal stabilizer musculature (27.9%) with the trunk exercises and all trunk stabilizers (37.7-54.3%) with the chest press. There was no effect of instability on the shoulder press. Unilateral shoulder press produced greater activation of the back stabilizers, and unilateral chest press resulted in higher activation of all trunk stabilizers, when compared with bilateral presses. Regardless of stability, the superman exercise was the most effective trunk-stabilizer exercise for back-stabilizer activation, whereas the side bridge was the optimal exercise for lower-abdominal muscle activation. Thus, the most effective means for trunk strengthening should involve back or abdominal exercises with unstable bases. Furthermore, trunk strengthening can also occur when performing resistance exercises for the limbs, if the exercises are performed unilaterally. © 2005 National Strength & Conditioning Association.
- Description: C1
- Description: 2003001184
- Authors: Behm, David , Leonard, Allison , Young, Warren , Bonsey, Andrew , MacKinnon, Scott N.
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 19, no. 1 (2005), p. 193-201
- Full Text:
- Reviewed:
- Description: The purpose of this cross-sectional study was to evaluate the effect of unstable and unilateral resistance exercises on trunk muscle activation. Eleven subjects (6 men and 5 women) between 20 and 45 years of age participated. Six trunk exercises, as well as unilateral and bilateral shoulder and chest presses against resistance, were performed on stable (bench) and unstable (Swiss ball) bases. Electromyographic activity of the upper lumbar, lumbosacral erector spinae, and lower-abdominal muscles were monitored. Instability generated greater activation of the lower-abdominal stabilizer musculature (27.9%) with the trunk exercises and all trunk stabilizers (37.7-54.3%) with the chest press. There was no effect of instability on the shoulder press. Unilateral shoulder press produced greater activation of the back stabilizers, and unilateral chest press resulted in higher activation of all trunk stabilizers, when compared with bilateral presses. Regardless of stability, the superman exercise was the most effective trunk-stabilizer exercise for back-stabilizer activation, whereas the side bridge was the optimal exercise for lower-abdominal muscle activation. Thus, the most effective means for trunk strengthening should involve back or abdominal exercises with unstable bases. Furthermore, trunk strengthening can also occur when performing resistance exercises for the limbs, if the exercises are performed unilaterally. © 2005 National Strength & Conditioning Association.
- Description: C1
- Description: 2003001184
Conflicting effects of fatigue and potentiation on voluntary force
- Behm, David, Button, Duane, Barbour, Glen, Butt, Jeremy, Young, Warren
- Authors: Behm, David , Button, Duane , Barbour, Glen , Butt, Jeremy , Young, Warren
- Date: 2004
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 18, no. 2 (2004), p. 365-372
- Full Text:
- Reviewed:
- Description: The objective of this study was to investigate whether a warm-up consisting of a series of maximal contractions would augment the force and activation of subsequent leg extensor contractions. Both voluntary and evoked isometric contractions were tested to determine the mechanisms underlying the response. Nine subjects were tested for twitch, tetanic, submaximal (30%), and maximal voluntary contractile (MVC) properties before and after (1, 5, 10, and 15 minutes) one to three 10-second MVCs. MVC force either did not change following 1-2 MVCs or was depressed at 10 and 15 minutes after 3 MVCs. MVC activation was decreased (4.4-6.9%) throughout recovery, whereas submaximal contractions were minimally affected. Although overall, twitches were potentiated (15.5-19.8%) posttest, 3 MVCs had significantly greater twitch potentiation than 1 or 2 MVCs at 5 and 10 minutes. Results suggest that voluntary and evoked contractions respond differently to prior 10-second MVCs. In the present study, a warm-up routine of 1-3 MVCs of a 10-second duration did not enhance subsequent voluntary performance.
- Description: C1
- Description: 2003001186
- Authors: Behm, David , Button, Duane , Barbour, Glen , Butt, Jeremy , Young, Warren
- Date: 2004
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 18, no. 2 (2004), p. 365-372
- Full Text:
- Reviewed:
- Description: The objective of this study was to investigate whether a warm-up consisting of a series of maximal contractions would augment the force and activation of subsequent leg extensor contractions. Both voluntary and evoked isometric contractions were tested to determine the mechanisms underlying the response. Nine subjects were tested for twitch, tetanic, submaximal (30%), and maximal voluntary contractile (MVC) properties before and after (1, 5, 10, and 15 minutes) one to three 10-second MVCs. MVC force either did not change following 1-2 MVCs or was depressed at 10 and 15 minutes after 3 MVCs. MVC activation was decreased (4.4-6.9%) throughout recovery, whereas submaximal contractions were minimally affected. Although overall, twitches were potentiated (15.5-19.8%) posttest, 3 MVCs had significantly greater twitch potentiation than 1 or 2 MVCs at 5 and 10 minutes. Results suggest that voluntary and evoked contractions respond differently to prior 10-second MVCs. In the present study, a warm-up routine of 1-3 MVCs of a 10-second duration did not enhance subsequent voluntary performance.
- Description: C1
- Description: 2003001186
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