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Motor effort training with low exercise intensity improves muscle strength and descending command in aging

View Article: PubMed Central - PubMed

ABSTRACT

This study explored the effect of high mental effort training (MET) and conventional strength training (CST) on increasing voluntary muscle strength and brain signal associated with producing maximal muscle force in healthy aging. Twenty-seven older adults (age: 75 ± 7.9 yr, 8 women) were assigned into 1 of 3 groups: MET group—trained with low-intensity (30% maximal voluntary contraction [MVC]) physical exercise combined with MET, CST group—trained with high-intensity muscle contractions, or control (CTRL) group—no training of any kind. MET and CST lasted for 12 weeks (5 sessions/week). The participants’ elbow flexion strength of the right arm, electromyography (EMG), and motor activity-related cortical potential (MRCP) directly related to the strength production were measured before and after training. The CST group had the highest strength gain (17.6%, P <0.001), the MET group also had significant strength gain (13.8%, P <0.001), which was not statistically different from that of the CST group even though the exercise intensity for the MET group was only at 30% MVC level. The CTRL group did not have significant strength changes. Surprisingly, only the MET group demonstrated a significant augmentation in the MRCP (29.3%, P <0.001); the MRCP increase in CST group was at boarder-line significance level (12.11%, P = 0.061) and that for CTRL group was only 4.9% (P = 0.539). These results suggest that high mental effort training combined with low-intensity physical exercise is an effective method for voluntary muscle strengthening and this approach is especially beneficial for those who are physically weak and have difficulty undergoing conventional strength training.

No MeSH data available.


Experimental setup (A) and strength testing and training schedules (B). Vertical lines in (B) indicate time in weeks, with the thin lines representing odd numbers and thick lines even numbers in the training period. Each thick vertical line also indicates a strength measurement (during-training strength measures were used to adjust training intensity). Note there were 3 strength measuremnts in the 3 week-pretraining period to obtain a truce baseline strength value.
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Figure 1: Experimental setup (A) and strength testing and training schedules (B). Vertical lines in (B) indicate time in weeks, with the thin lines representing odd numbers and thick lines even numbers in the training period. Each thick vertical line also indicates a strength measurement (during-training strength measures were used to adjust training intensity). Note there were 3 strength measuremnts in the 3 week-pretraining period to obtain a truce baseline strength value.

Mentions: Elbow flexion force of the right arm was measured by a force transducer (JR3 Universal Force-Moment Sensor System, Woodland, CA) with subjects seated, their left hand placed in a wrist cuff, forearm in a neutral position, and an elbow joint angle of ∼100°.[11] The elbow was supported at hip height and the shoulders and torso were kept in position using restraints (Fig. 1). Three MVC trials were performed in each measurement session and the highest force among the trials was analyzed. In each trial, participants were verbally encouraged to exert maximal force. Strength measurements were made before training and after the 12-week training period. The strength measurement conditions (arm and body positions, joint angles, etc.) were maintained across the evaluation sessions. In addition, the verbal instruction and encouragement for maximal force production were similar for all measurement sessions. The strength was measured 3 times in 3 separate sessions before training to ensure the pretraining strength was true maximal at the time.[18] The elbow flexion force data collected during the strength measurements were digitized at 100 samples per second using a data acquisition system (Micro 1401; Cambridge Electronic Design, Ltd, Cambridge, UK) and recorded on hard disk of a personal computer (PC).


Motor effort training with low exercise intensity improves muscle strength and descending command in aging
Experimental setup (A) and strength testing and training schedules (B). Vertical lines in (B) indicate time in weeks, with the thin lines representing odd numbers and thick lines even numbers in the training period. Each thick vertical line also indicates a strength measurement (during-training strength measures were used to adjust training intensity). Note there were 3 strength measuremnts in the 3 week-pretraining period to obtain a truce baseline strength value.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4998428&req=5

Figure 1: Experimental setup (A) and strength testing and training schedules (B). Vertical lines in (B) indicate time in weeks, with the thin lines representing odd numbers and thick lines even numbers in the training period. Each thick vertical line also indicates a strength measurement (during-training strength measures were used to adjust training intensity). Note there were 3 strength measuremnts in the 3 week-pretraining period to obtain a truce baseline strength value.
Mentions: Elbow flexion force of the right arm was measured by a force transducer (JR3 Universal Force-Moment Sensor System, Woodland, CA) with subjects seated, their left hand placed in a wrist cuff, forearm in a neutral position, and an elbow joint angle of ∼100°.[11] The elbow was supported at hip height and the shoulders and torso were kept in position using restraints (Fig. 1). Three MVC trials were performed in each measurement session and the highest force among the trials was analyzed. In each trial, participants were verbally encouraged to exert maximal force. Strength measurements were made before training and after the 12-week training period. The strength measurement conditions (arm and body positions, joint angles, etc.) were maintained across the evaluation sessions. In addition, the verbal instruction and encouragement for maximal force production were similar for all measurement sessions. The strength was measured 3 times in 3 separate sessions before training to ensure the pretraining strength was true maximal at the time.[18] The elbow flexion force data collected during the strength measurements were digitized at 100 samples per second using a data acquisition system (Micro 1401; Cambridge Electronic Design, Ltd, Cambridge, UK) and recorded on hard disk of a personal computer (PC).

View Article: PubMed Central - PubMed

ABSTRACT

This study explored the effect of high mental effort training (MET) and conventional strength training (CST) on increasing voluntary muscle strength and brain signal associated with producing maximal muscle force in healthy aging. Twenty-seven older adults (age: 75 ± 7.9 yr, 8 women) were assigned into 1 of 3 groups: MET group—trained with low-intensity (30% maximal voluntary contraction [MVC]) physical exercise combined with MET, CST group—trained with high-intensity muscle contractions, or control (CTRL) group—no training of any kind. MET and CST lasted for 12 weeks (5 sessions/week). The participants’ elbow flexion strength of the right arm, electromyography (EMG), and motor activity-related cortical potential (MRCP) directly related to the strength production were measured before and after training. The CST group had the highest strength gain (17.6%, P <0.001), the MET group also had significant strength gain (13.8%, P <0.001), which was not statistically different from that of the CST group even though the exercise intensity for the MET group was only at 30% MVC level. The CTRL group did not have significant strength changes. Surprisingly, only the MET group demonstrated a significant augmentation in the MRCP (29.3%, P <0.001); the MRCP increase in CST group was at boarder-line significance level (12.11%, P = 0.061) and that for CTRL group was only 4.9% (P = 0.539). These results suggest that high mental effort training combined with low-intensity physical exercise is an effective method for voluntary muscle strengthening and this approach is especially beneficial for those who are physically weak and have difficulty undergoing conventional strength training.

No MeSH data available.