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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.


An example of time–frequency–power plots for a subject in the CST group before (top) and after (bottom) training at C3 (left) and Cz (right) recording locations. In each plot, the y-axis indicates EEG frequency and x-axis time points during the MVC trial with time 0 (not shown) depicting beginning of the trial, and color bar on right represents the power scales (red = greater power). Note a clear increase in power at high theta (7–8 Hz) frequency after training.
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Figure 6: An example of time–frequency–power plots for a subject in the CST group before (top) and after (bottom) training at C3 (left) and Cz (right) recording locations. In each plot, the y-axis indicates EEG frequency and x-axis time points during the MVC trial with time 0 (not shown) depicting beginning of the trial, and color bar on right represents the power scales (red = greater power). Note a clear increase in power at high theta (7–8 Hz) frequency after training.

Mentions: EEG frequency power has previously been shown to be related to motor activities.[30] In particular, EEG frequency power has been found to be proportionally related to muscle contraction force.[31] In this study, we found that power of EEG frequency increased significantly in both the CST and MET groups. However, only the MET group had significant power increases at both alpha (8–14 Hz, Fig. 4) and beta (14–35 Hz, Fig. 5) bands at the Cz (over supplementary motor area, Fig. 4) location. The CST group showed a significant power elevation (54.61 ± 29.39%, P <0.05) at theta band (4–8 Hz) at Cz location (not shown). The CTL group experienced no significant EEG frequency power alterations. Fig. 6 shows an example of enhanced EEG power of frequency at high theta or low alpha (7–8 Hz) as a function of time for the strength measurement MVC trials of a subject in CST group before and after training. For each plot in Fig. 6 the y-axis indicates EEG frequency and x-axis time points during the MVC trial with time 0 (not shown) depicting beginning of the trial, and color bar on right represents the power scales (red = greater power). It is clear that in this individual, the theta (4–8 Hz) frequency power increased substantially after the MET training at both C3 (left) and Cz (right) locations.


Motor effort training with low exercise intensity improves muscle strength and descending command in aging
An example of time–frequency–power plots for a subject in the CST group before (top) and after (bottom) training at C3 (left) and Cz (right) recording locations. In each plot, the y-axis indicates EEG frequency and x-axis time points during the MVC trial with time 0 (not shown) depicting beginning of the trial, and color bar on right represents the power scales (red = greater power). Note a clear increase in power at high theta (7–8 Hz) frequency after training.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC4998428&req=5

Figure 6: An example of time–frequency–power plots for a subject in the CST group before (top) and after (bottom) training at C3 (left) and Cz (right) recording locations. In each plot, the y-axis indicates EEG frequency and x-axis time points during the MVC trial with time 0 (not shown) depicting beginning of the trial, and color bar on right represents the power scales (red = greater power). Note a clear increase in power at high theta (7–8 Hz) frequency after training.
Mentions: EEG frequency power has previously been shown to be related to motor activities.[30] In particular, EEG frequency power has been found to be proportionally related to muscle contraction force.[31] In this study, we found that power of EEG frequency increased significantly in both the CST and MET groups. However, only the MET group had significant power increases at both alpha (8–14 Hz, Fig. 4) and beta (14–35 Hz, Fig. 5) bands at the Cz (over supplementary motor area, Fig. 4) location. The CST group showed a significant power elevation (54.61 ± 29.39%, P <0.05) at theta band (4–8 Hz) at Cz location (not shown). The CTL group experienced no significant EEG frequency power alterations. Fig. 6 shows an example of enhanced EEG power of frequency at high theta or low alpha (7–8 Hz) as a function of time for the strength measurement MVC trials of a subject in CST group before and after training. For each plot in Fig. 6 the y-axis indicates EEG frequency and x-axis time points during the MVC trial with time 0 (not shown) depicting beginning of the trial, and color bar on right represents the power scales (red = greater power). It is clear that in this individual, the theta (4–8 Hz) frequency power increased substantially after the MET training at both C3 (left) and Cz (right) locations.

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&#8202;&plusmn;&#8202;7.9 yr, 8 women) were assigned into 1 of 3 groups: MET group&mdash;trained with low-intensity (30% maximal voluntary contraction [MVC]) physical exercise combined with MET, CST group&mdash;trained with high-intensity muscle contractions, or control (CTRL) group&mdash;no training of any kind. MET and CST lasted for 12 weeks (5&#8202;sessions/week). The participants&rsquo; 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&#8202;&lt;0.001), the MET group also had significant strength gain (13.8%, P&#8202;&lt;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&#8202;&lt;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.