Surface electromyographic activity of the erector spinae and multifidus during arm- and leg-ergometer exercises in young healthy men.

Objectives: Ergometer exercise was considered a new loading method that can be used for participants who are unable to assume the core strengthening exercise posture commonly used to strengthen the erector spinae and multifidus. This study aimed to investigate with healthy participants whether arm and leg ergometers could be used for core strengthening exercises and whether different exercise sites would affect the results. Methods: The study was conducted with 15 healthy adult male participants aged 20-35 years. The intervention consisted of arm- and leg-ergometer exercises performed by the participants. The exercise protocol consisted of three 1-min sessions (rest, 50W, and 100 W), which were measured consecutively. Surface electromyography (sEMG) was measured during the sessions. Maximal voluntary contraction (MVC) of the erector spinae and multifidus was also measured, during which sEMG was measured. The sEMG during ergometer exercise was calculated as a percentage of the MVC (calculated as % MVC). The root mean square (RMS) was recorded from the sEMG activity. Muscle activity of the erector spinae and multifidus was compared between ergometer exercises and between intensity levels. Heart rate (HR) was recorded by electrocardiogram. Results: In the arm-ergometer exercise, the % MVC values of the erector spinae were 6.3 ± 3.1, 10.9 ± 5.4, and 16.9 ± 8.3% at rest, 50 W, and 100 W conditions, respectively. The multifidus was 4.6 ± 2.9, 9.2 ± 5.6, and 12.6 ± 7.6% at rest, 50 W, and 100 W conditions, respectively. The respective % MVC values during the leg-ergometer exercise were 3.8 ± 1.7, 7.2 ± 3.8, and 10.4 ± 4.0% at rest, 50 W, and 100 W conditions, respectively. Leg-ergometer exercises were 2.6 ± 2.1, 6.9 ± 5.7, and 10.3 ± 6.8% at rest, 50 W, and 100 W conditions, respectively. The activities of the two muscles increased at comparable levels with increased workload in both types of exercises (p < 0.01, each). HR increased with the increased workload and the increase was larger during arm-than leg-ergometer exercises. Conclusion: These results demonstrate that both arm- and leg-ergometer exercises are potentially alternative methods for erector spinae and multifidus training for healthy participants. Further research is needed to target elderly.

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

Objectives: 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.

Comparison of erector spinae fatigability between female patients with Parkinson's disease and healthy individuals: a cross sectional pilot study.

BACKGROUND: Postural abnormality is one of the main symptoms of Parkinson's disease (PD). The erector spinae muscles play an important role in maintaining an upright posture, but the fatigability of the erector spinae in patients with PD is unknown. The purpose of this study was to compare the trunk extension maximum voluntary contraction (MVC) and the fatigability of the erector spinae between female patients with PD and healthy volunteers. METHODS: Th participants of this cross-sectional pilot study comprised 19 patients with PD and nine healthy volunteers matched for sex, age, and physical characteristics as a control group. The MVC of all participants was measured, and after sufficient rest, the Sørensen back endurance test was conducted to the point of exhaustion. The muscle activity of the erector spinae during the Sørensen back endurance test was measured using surface electromyography. The median frequency (MF) slope, which is an index of fatigability, was calculated from the recorded surface muscle activity by means of power spectrum analysis using a Fast Fourier transformation. RESULTS: Nine of the 19 patients with PD were unable to perform the Sørensen back endurance test, and a lower proportion of the PD group were able to perform it compared with the control group. The MVC of those patients with PD who were able to perform the Sørensen back endurance test was lower than that of the control group, and the time for which the pose could be maintained was shorter. There was no significant difference between the MF slope on the left and right side in the PD group, and it was higher on both sides than in the control group. CONCLUSION: This is the first study to demonstrate a reduction of maximum muscle strength and great fatigability of the erector spinae in patients with PD. This discovery strongly underlines the need for paraspinal muscle training from an early stage with the aim of preventing the progression of postural abnormality in patients with PD.

Case Report: A Rehabilitation Practice Report During ICU Management for a Patient With Multiple Disabilities Due to COVID-19 Pneumonia and COPD.

Patients with severe coronavirus disease (COVID-19) and admitted to the intensive care unit (ICU) are at high risk of developing ICU-acquired weakness and disuse syndrome. Although their medical management may include prolonged deep sedation for pulmonary protection and ventilator management, we aim for early mobilization of these patients with COVID-19. We present the case of a 71-year-old man with chronic obstructive pulmonary disease (COPD) and COVID-19 pneumonia. Passive range of motion training and sitting on the edge of the bed were started in the ICU while the patient was under deep sedation. His activities of daily living eventually improved to where he could independently walk to the toilet without respiratory distress. Patients with severe COVID-19 who require mechanical ventilation are at risk of muscle weakness and exercise intolerance. These patients require rehabilitation therapy, beginning in the acute phase of illness, to recover their physical function. Although validation with a larger cohort is necessary, our results suggest that patients with COPD and COVID-19 pneumonia should undergo rehabilitation concurrently with status-driven changes in respiratory management.

Differences in fatigability of vastus medialis muscle between patients with limb symmetry index of <90% and ≥90% after chronic anterior cruciate ligament reconstruction.

BACKGROUND: A limb symmetry index (LSI) of ≥90% for the quadriceps is recommended for return to sports activity after anterior cruciate ligament reconstruction (ACLR). However, there is no information on differences in muscle fatigability between patients with LSI of <90% and ≥90%. The aim of this study was to assess the difference in quadriceps muscle fatigability on the involved side between post-ACLR patients with LSI of <90% and ≥90%. We hypothesized that there were differences between the two groups in muscle fatigability on the involved side reflecting difference in muscle fiber composition in the vastus medialis (VM) muscle. METHODS: The study subjects were 18 adult men who had undergone ACLR followed by rehabilitation therapy. LSI was <90% in 10 and ≥90% in 8 adult men. Surface electromyography (EMG) of the VM muscle was recorded during sustained quadriceps muscle isometric contraction. The median frequency (MF) was computed from the raw EMG signal using fast Fourier transform spectrum analysis. The MF slope was also calculated. RESULTS: There were no differences in anthropometric characteristics, time since ACLR, anterior tibial translation and peak torque of knee extension on the involved side between the two groups. However, MF slope was significantly lower in the LSI ≥ 90% group than the <90% group. CONCLUSION: Our results demonstrated fatigue-resistant vastus medialis in post-ACLR patients with LSI ≥90% compared to those with LSI <90%. The finding adds support to the use of ≥90% as the cutoff value for LSI for return of post-ACLR patients to sports activity.