Electromyographic Power Spectral Analysis Research Articles

Differences in Muscle Fatigability of Vastus Medialis between Sexes Using Surface Electromyographic Power Spectral Analysis in Healthy Adults.

ABSTRACTObjectives:With a relatively high percentage of type I fibers in the vastus medialis (VM), its fatigability may be more sensitive to the effects of muscle activity in the quadriceps. However, sex-related differences in the muscle fatigability of the VM remain unknown. The purpose of the present study was to assess the differences in fatigability of the VM between healthy adult men and women.Methods:Surface electromyographic (EMG) activities of VM oblique (VMO) and VM long (VML) were recorded during sustained isometric contraction on a leg press machine. The results of EMG power spectral analysis were compared between healthy adult men and women. The decline in the median frequency (MF), defined as MF slope, was calculated using spectrum analysis after fast Fourier transform of the raw EMG signals of VMO and VML.Results:The endurance time and the MF slopes of the VMO and VML were significantly longer and lower, respectively, in women than in men. The present results demonstrated that both VMO and VML are more fatigue-resistant in women than in men.Conclusions:Understanding the sex differences in fatigability could help to design more effective exercise regimens for VMO and VML in healthy individuals. A similar approach should be considered when prescribing practical exercise regimens for patients with muscle atrophy.

Fatigue-related differences in erector spinae between adult spinal deformity patients and healthy individuals using surface electromyographic power spectral analysis

Fatigue-related differences in erector spinae between adult spinal deformity patients and healthy individuals using surface electromyographic power spectral analysis

Properties of Paraspinal Muscles in Japanese High School Baseball Players With Terminal-Stage Lumbar Spondylolysis

BackgroundLumbar spondylolysis is a defect in the pars interarticularis that is common in young athletes; the stress distribution at the pars interarticularis is the highest in extension and rotation movements. The paraspinal muscles play an important role in stabilization of the lumbar spine; however, no study has assessed the properties of paraspinal muscles in athletes with lumbar spondylolysis. ObjectiveTo evaluate the properties of paraspinal muscles in athletes with lumbar spondylolysis. DesignCross-sectional study. SettingLaboratory. ParticipantsSix high school baseball players with terminal-stage lumbar spondylolysis and 11 high school baseball players without organic lumbar lesions of similar anthropometric characteristics. MethodsAll subjects performed the unsupported trunk holding test combined with surface electromyographic (EMG) power spectral analysis until exhaustion. The results of EMG power spectral analysis were compared between the spondylolysis and control groups. Main Outcome MeasurementsThe median frequency (MF) was computed from the raw EMG signal of the erector spinae and multifidus during trunk holding test using fast Fourier transform spectrum analysis. The initial MF and MF slope were calculated. ResultsNo significant differences in endurance time were found between the spondylolysis and control groups. The initial MF and the MF slopes of the erector spinae and multifidus were significantly lower in the spondylolysis group than in the control group. ConclusionsThe results suggest lower fast-twitch motor unit recruitment in the erector spinae and multifidus of high school baseball players with terminal-stage lumbar spondylolysis compared with the control. Level of EvidenceIV

Fatigue-related differences in erector spinae between prepubertal children and young adults using surface electromyographic power spectral analysis.

The erector spinae is more resistant to fatigue in adult women than men. However, no study has reported the sex differences in back muscle fatigue in children. The aim of this study was to evaluate the fatigability of erector spinae in prepubertal children and adults, in both males and females. Fourteen prepubertal boys, 13 prepubertal girls, 14 adult men, and 13 adult women performed the Sørensen back isometric endurance test until exhaustion. The results of electromyographic (EMG) power spectral analysis of erector spinae were compared between both age groups and sexes. The slopes of EMG power spectral median and mean power frequency were significantly higher in males than in females, in both age groups. Furthermore, the slopes were significantly lower in prepubertal children than in adults, in both males and females. Our results showed major differences in the fatigue threshold of the erector spinae between boys and girls and children and adults. The muscle fatigued faster in prepubertal boys and adult men than in prepubertal girls and adult women. In both sexes, a lower slope of EMG power spectrum parameters of the erector spinae was noted during endurance test in prepubertal children compared to adults.

Age-related sex differences in erector spinae muscle endurance using surface electromyographic power spectral analysis in healthy humans

Background contextPrevious studies reported that the erector spinae muscle is more resistant to fatigue in healthy adult women than in men. However, no study has reported changes in back muscle fatigue with aging in healthy men and women. PurposeThe aim of this study was to evaluate age-related changes in muscle fatigue of erector spinae muscle in men and women. Study design/settingThis cross-sectional study was conducted in a laboratory. Patient sampleFifty-three healthy subjects (11 elderly men, 11 elderly women, 17 young men, and 14 young women) without low back pain history. Outcome measuresThe median frequency (MF) and mean power frequency (MPF) during trunk holding test were derived from the raw electromyographic (EMG) signal using Fast Fourier Transform spectrum analysis program. The rates of changes in MF and MPF were calculated. MethodsSubjects performed the unsupported trunk holding test until exhaustion. The results of power spectral analysis of the EMG activity of the left erector spinae muscle were compared in both age groups and sexes. ResultsThe endurance time in young men was significantly shorter than in young women. The slopes of MF and MPF in young men were significantly higher than in young women. There were no significant differences in MF and MPF slopes of elderly men and elderly women. Furthermore, the MF and MPF slopes were significantly lower in elderly men than young men but similar in the two women groups. ConclusionsAge-related changes in the slopes of MF and MPF of erector spinae muscle occur in healthy men but not in healthy women.

Gender differences in spectral and entropic measures of erector spinae muscle fatigue.

Electromyographic power spectral analysis is a valuable measurement; however, conflicting results have been reported for amplitude and frequency changes during a fatiguing submaximal muscle contraction. This study compared gender differences for two analyses in subjects with low back pain (LBP). Distinct gender differences are found in musculoskeletal illness/dysfunction, and we examined the effect of gender on entropy and median frequency (MF) slope in a cohort of subjects with LBP. A total of 44 subjects (24 female and 20 male) completed the modified Sorenson test. These subjects ranged in age from 26 to 64 years old, with an average age of 49.9 +/- 9.4 years. Overall, a significant fatigability difference was found based on MF slope (F = 21.33, p = 0.001) and entropy measures (F = 68.26, p = 0.001) of the back muscles. While the MF slope was not different (F = 0.44, p = 0.51) between genders, the entropy values were higher for the male subjects than for the female subjects (F = 6.70, p = 0.01). These results indicate that the Shannon entropy measure differentiates between genders. Further studies are needed to evaluate the effectiveness of using nonlinear analysis as a measurement tool.

Electromyographic Power Spectral Analysis of the Paraspinal Muscles: Reliability study

Summary Background and Purpose Despite previous studies on the reliability of median frequency (MF) and median frequency slope (MFS) as specific surface electromyography (SEMG) measures of back muscle function, there is still no general consensus regarding the results. A reliability study was carried out to determine the test-retest reliability (within and between-days) of SEMG power spectral analysis of paraspinal muscle activity in healthy subjects. Methods Fifteen volunteer subjects with no history of low back pain were tested. The unsupported trunk holding position was used to measure initial MF and MFS three times. Two measurements were taken on the same day with five minutes interval and the third was taken one week later. Results For initial MF, the high ICC values (0.82-0.92) and high level of agreement between measurements for multifidus and iliocostalis indicated high within and between-days reliability. For MFS, the ICC values (0.65-0.82) and high (for multifidus) to moderate (for iliocostalis) level of agreement between measurements demonstrated high within-day reliability for multifidus and moderate for iliocostalis. Between-days reliability of MFS was found to be good for multifidus and moderately good for iliocostalis with ICC values of 0.60-0.85 and high to moderate level of agreement. Conclusion In this study the SEMG power spectral analysis was shown to be a reliable method of measuring back muscle activity in an unsupported trunk holding test, when measurements are taken in healthy subjects by the same investigator.

Spectral electromyographic fatigue analysis of back muscles in healthy adult women compared with men

Objective and Design: To investigate the difference in back muscle endurance between normal adult women and men using surface electromyographic (EMG) power spectral analyses. Methods: Forty-five healthy subjects (22 men and 23 women) were studied during an unsupported trunk holding test for 120 seconds. Recording surface electrodes were placed over each erector spinae muscle at L1 level. Outcome Measures: Median frequency (MF), mean power frequency (MPF), and zero crossing rate (ZCR) were evaluated using the ME3000P Fast Fourier Transform spectrum analysis program. The rate of change was determined for each parameter during the test, and correlation was examined by Pearson's correlation. Results: The negative slopes of all indices of back muscle fatigue were significantly steeper in men than in women. Conclusion: Our results indicated that the trunk holding test combined with EMG power spectral analysis of lumbosacral muscles is useful for the evaluation of fatigue performance of these muscles. Our results also showed a higher muscle endurance in healthy adult women than in men.

Electromyographic power spectral analysis of sternocleidomastoid muscle during sustained voluntary clenching

The purpose of this study was to investigate the changes of the activity of the sternocleidomastoid (SCM) muscles during sustained voluntary clenching. Ten healthy male subjects without any occlusal functional problems were asked to clench as long as possible in the intercuspal position while keeping the electromyographic activity of the masseter muscle at the 50% maximum voluntary contraction. Frequency analysis was carried out by computer using a fast Fourier transform algorithm to obtain the power spectrum of the SCM muscle during the fatiguing process and the recovery process. The results were as follows: 1. Sustained activities of the SCM muscles were observed during sustained voluntary clenching. 2. The power spectra of the SCM muscles significantly shifted to a lower frequency as time elapsed. 3. The power spectra of the SCM muscles obtained three minutes after relaxation recovered to those of the beginning of clenching. These findings indicated that muscle fatigue may be induced in the SCM muscle during sustained voluntary clenching and that electromyographic power spectral analysis can be used as a noninvasive, objective, and quantitative index of SCM muscle fatigue.

Reliability of electromyographic power spectral analysis of back muscle endurance in healthy subjects

Objective and Design: To investigate the reliability (within-day and between-days) of measurements of electromyographic (EMG) power spectral values in measurement of the fatigue rate of the back muscles. Methods: Twelve healthy male subjects were tested in the unsupported trunk holding position for 60 seconds. Two trials were performed on each of two separate sessions 3 days apart. Surface recording electrodes were placed over the iliocostalis lumborum and multifidus and a branched electrode technique was used to decrease cross-talk. Outcome Measures: Median frequency (MF) was extracted from the EMG signals by fast Fourier transform. Initial MF and the MF slope over time were computed from linear regression analysis. The reliability of the initial MF and the MF slope of the iliocostalis lumborum and multifidus was examined by Pearson's product moment correlation coefficients (Pearson's r), paired t tests, and a one-way analysis of variance (ANOVA) from which intrasubject coefficients of variation (CV intra and intraclass correlation coefficients (ICC) were derived. Results: For the initial MF, within-day and between-days reliability of the iliocostalis lumborum and multifidus were good (Pearson/s r = .79–.94 nonsignificant paired t test, CV intra = 6.5% to 8.5%, ICC = .79–.93). The MF slope showed moderate variability for the iliocostalis lumborum (Pearson's r = .39–.55, nonsignificant paired t test, CV intra = 33.0% to 48.7%, ICC = .37–.56) while better reliability was found for the multifidus (Pearson's r = .77–.87, nonsignificant paired t test, CV intra = 25.8% to 27.5%, ICC = .78–.82). Conclusion: The present study indicated that the trunk holding test with the use of EMG power spectral analysis can be a reliable method to measure the fatigue rate of the back muscles if adequate measures are employed to minimize cross-talk. The better reliability of monitoring the fatigue rate of the multifidus may lead to its future use as a clinical measure.

Electromyographic Power Spectrum Analysis of the Paraspinal Muscles

As a prerequisite to the use of electromyographic power spectral analysis of the paraspinal muscles as a low-back pain treatment outcome measure, the long-term reliability of the technique was assessed. The myoelectric signals of the multifidus and iliocostalis lumborum muscles of healthy sedentary women were analyzed with regard to spectral parameters during a constant-force contraction, before and after a 3-month period. Results indicated that for both muscles, estimates of initial median frequency and amplitude had high test/retest reliability, but that the recovery and left-right difference parameters were not stable. Using a confidence interval method, test/retest variation for the fatigue parameter was found to be within the range of variability of potentially underlying metabolic processes.

咬みしめ時の咀嚼筋筋電図の周波数分析―顎間垂直距離を増加させた場合―

咬みしめ時の咀嚼筋筋電図の周波数分析―顎間垂直距離を増加させた場合―

下顎偏心位咬みしめ時における咀嚼筋筋電図の周波数分析

下顎偏心位咬みしめ時における咀嚼筋筋電図の周波数分析

咬みしめ時の咀嚼筋筋電図の周波数分析

咬みしめ時の咀嚼筋筋電図の周波数分析

Electromyographic power spectral analysis of jaw opening and closing muscles during fatigue.

Electromyographic power spectral analysis of jaw opening and closing muscles during fatigue.