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The feasibility of measuring the activation of the trunk muscles in healthy older adults during trunk stability exercises.

Hanada EY, Hubley-Kozey CL, McKeon MD, Gordon SA - BMC Geriatr (2008)

Bottom Line: As the older adult population increases, the potential functional and clinical burden of trunk muscle dysfunction may be significant.Older adults were able to successfully complete the trunk stability protocol that was developed for younger adults with some minor modifications.The temporal waveforms for the abdominal muscles showed a degree of synchrony among muscles, except for the early activation from the internal oblique prior to lifting the leg off the table.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Physiotherapy, Dalhousie University, Halifax, Canada. Edwin.Hanada@cdha.nshealth.ca

ABSTRACT

Background: As the older adult population increases, the potential functional and clinical burden of trunk muscle dysfunction may be significant. An evaluation of risk factors including the impact of the trunk muscles in terms of their temporal firing patterns, amplitudes of activation, and contribution to spinal stability is required. Therefore, the specific purpose of this study was to assess the feasibility of measuring the activation of trunk muscles in healthy older adults during specific leg exercises with trunk stabilization.

Methods: 12 asymptomatic adults 65 to 75 years of age were included in the study. Participants performed a series of trunk stability exercises, while bilateral activation of abdominal and back extensor muscles was recorded by 24 pairs of Meditrace surface electrodes. Maximal voluntary isometric contractions (MVIC) were performed for electromyographic (EMG) normalization purposes. EMG waveforms were generated and amplitude measures as a percentage of MVIC were calculated along with ensemble average profiles. 3D kinematics data were also recorded, using an electromagnetic sensor placed at the left lateral iliac crest. Furthermore, a qualitative assessment was conducted to establish the participant's ability to complete all experimental tasks.

Results: Excellent quality abdominal muscle activation data were recorded during the tasks. Participants performed the trunk stability exercises with an unsteady, intermittent motion, but were able to keep pelvic motion to less than 10 degrees . The EMG amplitudes showed that during these exercises, on average, the older adults recruited their abdominal muscles from 15-34% of MVIC and back extensors to less than 10% of MVIC. There were similarities among the abdominal muscle profiles. No participants reported pain during the testing session, although 3 (25%) of the participants reported delayed onset muscle soreness during follow up that was not functionally limiting.

Conclusion: Older adults were able to successfully complete the trunk stability protocol that was developed for younger adults with some minor modifications. The collected EMG amplitudes were higher than those reported in the literature for young healthy adults. The temporal waveforms for the abdominal muscles showed a degree of synchrony among muscles, except for the early activation from the internal oblique prior to lifting the leg off the table.

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Sample ensemble average waveforms. Sample ensemble average waveforms normalized to %MVIC for the 6 abdominal muscles during 3 levels of the exercise progression. [A] Level 1 [B] Level 2 [C] Level 3. Note that three participants did not produce maximal activations during normalization exercises. Coefficients of variation are in Table 4.
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Figure 4: Sample ensemble average waveforms. Sample ensemble average waveforms normalized to %MVIC for the 6 abdominal muscles during 3 levels of the exercise progression. [A] Level 1 [B] Level 2 [C] Level 3. Note that three participants did not produce maximal activations during normalization exercises. Coefficients of variation are in Table 4.

Mentions: Although there were some challenges to the fixation of the electrodes to the participants' skin that included: 1) difficulty in locating landmarks for EMG electrode placement because of loose skin and excess adipose tissue, and 2) electrode adherence to the skin during movement, all EMG signals were of high quality, with excellent signal to noise ratios. Examples of the abdominal signals are illustrated in Figure 3. There was low amplitude noise from the magnetic motion sensors, but this had no affect on the abdominal muscles and had no visible effect on the back extensor muscles. Pilot work showed that the low level noise decreased the further the sensor was from the transmitter, and that it was negligible when at a distance greater than 60 cm. For the exercise tasks, this distance was greater than 60 cm. The mean amplitude for all 24 muscle sites is presented in Table 3. As expected, participants activated back extensor muscles to low amplitudes, with all sites less than 10% MVIC. The abdominal muscles were recruited to amplitudes from 15% to 35% MVIC (lower amplitudes for level 1, higher amplitudes for level 3). The ensemble average profiles are in Figure 4 for levels 1–3. The coefficients of variation for these waveforms are found in Table 4. These profiles illustrate how the muscles respond to the changes in loading throughout the trunk stability tasks. Of note is the higher bilateral internal oblique amplitude initially for all exercise levels.


The feasibility of measuring the activation of the trunk muscles in healthy older adults during trunk stability exercises.

Hanada EY, Hubley-Kozey CL, McKeon MD, Gordon SA - BMC Geriatr (2008)

Sample ensemble average waveforms. Sample ensemble average waveforms normalized to %MVIC for the 6 abdominal muscles during 3 levels of the exercise progression. [A] Level 1 [B] Level 2 [C] Level 3. Note that three participants did not produce maximal activations during normalization exercises. Coefficients of variation are in Table 4.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2651173&req=5

Figure 4: Sample ensemble average waveforms. Sample ensemble average waveforms normalized to %MVIC for the 6 abdominal muscles during 3 levels of the exercise progression. [A] Level 1 [B] Level 2 [C] Level 3. Note that three participants did not produce maximal activations during normalization exercises. Coefficients of variation are in Table 4.
Mentions: Although there were some challenges to the fixation of the electrodes to the participants' skin that included: 1) difficulty in locating landmarks for EMG electrode placement because of loose skin and excess adipose tissue, and 2) electrode adherence to the skin during movement, all EMG signals were of high quality, with excellent signal to noise ratios. Examples of the abdominal signals are illustrated in Figure 3. There was low amplitude noise from the magnetic motion sensors, but this had no affect on the abdominal muscles and had no visible effect on the back extensor muscles. Pilot work showed that the low level noise decreased the further the sensor was from the transmitter, and that it was negligible when at a distance greater than 60 cm. For the exercise tasks, this distance was greater than 60 cm. The mean amplitude for all 24 muscle sites is presented in Table 3. As expected, participants activated back extensor muscles to low amplitudes, with all sites less than 10% MVIC. The abdominal muscles were recruited to amplitudes from 15% to 35% MVIC (lower amplitudes for level 1, higher amplitudes for level 3). The ensemble average profiles are in Figure 4 for levels 1–3. The coefficients of variation for these waveforms are found in Table 4. These profiles illustrate how the muscles respond to the changes in loading throughout the trunk stability tasks. Of note is the higher bilateral internal oblique amplitude initially for all exercise levels.

Bottom Line: As the older adult population increases, the potential functional and clinical burden of trunk muscle dysfunction may be significant.Older adults were able to successfully complete the trunk stability protocol that was developed for younger adults with some minor modifications.The temporal waveforms for the abdominal muscles showed a degree of synchrony among muscles, except for the early activation from the internal oblique prior to lifting the leg off the table.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Physiotherapy, Dalhousie University, Halifax, Canada. Edwin.Hanada@cdha.nshealth.ca

ABSTRACT

Background: As the older adult population increases, the potential functional and clinical burden of trunk muscle dysfunction may be significant. An evaluation of risk factors including the impact of the trunk muscles in terms of their temporal firing patterns, amplitudes of activation, and contribution to spinal stability is required. Therefore, the specific purpose of this study was to assess the feasibility of measuring the activation of trunk muscles in healthy older adults during specific leg exercises with trunk stabilization.

Methods: 12 asymptomatic adults 65 to 75 years of age were included in the study. Participants performed a series of trunk stability exercises, while bilateral activation of abdominal and back extensor muscles was recorded by 24 pairs of Meditrace surface electrodes. Maximal voluntary isometric contractions (MVIC) were performed for electromyographic (EMG) normalization purposes. EMG waveforms were generated and amplitude measures as a percentage of MVIC were calculated along with ensemble average profiles. 3D kinematics data were also recorded, using an electromagnetic sensor placed at the left lateral iliac crest. Furthermore, a qualitative assessment was conducted to establish the participant's ability to complete all experimental tasks.

Results: Excellent quality abdominal muscle activation data were recorded during the tasks. Participants performed the trunk stability exercises with an unsteady, intermittent motion, but were able to keep pelvic motion to less than 10 degrees . The EMG amplitudes showed that during these exercises, on average, the older adults recruited their abdominal muscles from 15-34% of MVIC and back extensors to less than 10% of MVIC. There were similarities among the abdominal muscle profiles. No participants reported pain during the testing session, although 3 (25%) of the participants reported delayed onset muscle soreness during follow up that was not functionally limiting.

Conclusion: Older adults were able to successfully complete the trunk stability protocol that was developed for younger adults with some minor modifications. The collected EMG amplitudes were higher than those reported in the literature for young healthy adults. The temporal waveforms for the abdominal muscles showed a degree of synchrony among muscles, except for the early activation from the internal oblique prior to lifting the leg off the table.

Show MeSH
Related in: MedlinePlus