Lifting tasks are manual material-handling activities and are commonly associated with work-related low back disorders. Instrument-based assessment tools are used to quantitatively assess the ...biomechanical risk associated with lifting activities. This study aims at highlighting different motor strategies in people with and without low back pain (LBP) during fatiguing frequency-dependent lifting tasks by using parameters of muscle coactivation. A total of 15 healthy controls (HC) and eight people with LBP performed three lifting tasks with a progressively increasing lifting index (LI), each lasting 15 min. Bilaterally erector spinae longissimus (ESL) activity and rectus abdominis superior (RAS) were recorded using bipolar surface electromyography systems (sEMG), and the time-varying multi-muscle coactivation function (TMCf) was computed. The TMCf can significantly discriminate each pair of LI and it is higher in LBP than HC. Collectively, our findings suggest that it is possible to identify different motor strategies between people with and without LBP. The main finding shows that LBP, to counteract pain, coactivates the trunk muscles more than HC, thereby adopting a strategy that is stiffer and more fatiguing.
•The trunk muscle mass of stroke patients is related to the discharge Functional Independence Measure-motor score.•This association is stronger than that between the Functional Independence ...Measure-motor score and the appendicular skeletal muscle mass index.•Self-care and locomotion are associated with trunk muscle mass in stroke patients.•Transfer and locomotion are associated with appendicular skeletal muscle mass.
The aim of this study was to evaluate the effects of trunk muscle mass on functional prognosis, including activities of daily living (ADLs), at hospital discharge in patients with acute stroke.
This retrospective cohort study included hospitalized patients with acute stroke. Trunk muscle mass was measured using bioelectrical impedance analysis within 5 d of admission. The primary outcome was ADLs at hospital discharge, assessed using the Functional Independence Measure-motor items (FIM-motor). The secondary outcomes were hospital length of stay and discharge to home. Multivariate analyses were performed to determine the association between trunk muscle mass and FIM subitems.
Data from 212 patients (mean age 72.7 y; 143 men) were included in the analysis. The median trunk muscle mass index (TMI) was 8.2 kg/m2 in men and 6.7 kg/m2 in women. Patients in the high TMI group were younger and had a higher FIM-motor score at discharge (P < 0.001). In multivariate analyses, TMI was positively associated with the FIM-motor score at discharge (β = 0.240, P < 0.001). FIM-self-care (β = 0.351, P < 0.001) and locomotion (β = 0.331, P < 0.001) were positively associated with the TMI.
Trunk muscle mass is associated with ADLs at hospital discharge after acute stroke. TMI is important for evaluating functional prognosis in patients with acute stroke.
Many studies have measured stature change arising from loads imposed on the spine during sitting. To improve stature recovery, it is important to stabilise the lumbar spine and compensate forces from ...the upper body. The abdominal drawing-in maneuver (ADIM) technique has been found to mainly activate deep trunk muscles. The purpose of this study was to determine whether activation of deep trunk muscles by the ADIM technique could immediately improve stature recovery during prolonged sitting. Twenty-four patients with chronic low back pain (CLBP) were randomly allocated into different orders of experimental conditions: control (sitting without ADIM technique) and intervention conditions (sitting with ADIM technique). The latter condition required participants to complete ADIM technique for 1 min and repeat it three times throughout 41 min prolonged sitting time. Stature recovery was improved by 3.292 mm in the intervention condition compared with control condition (p-value = 0.001). Our finding demonstrated that ADIM technique improved stature recovery.
Practitioner Summary: Prolonged sitting seemingly harms sedentary workers' health, particularly affecting the lower back. Activation of deep trunk muscles using abdominal drawing-in maneuver technique can promote spinal recovery. Clinicians can teach abdominal drawing-in maneuver technique to activate deep trunk muscles in chronic low back pain, thereby promoting self-management of seated stature recovery.
Abbrevations: ADIM: abdominal drawing-in maneuver; RA: rectus abdominis; ICLT: iliocostalis lumborum pars thoracis; LM: lumbar multifidus; TrA: transversus abdominis; IO: internal oblique; CLBP: chronic low back pain; LBP: low back pain; RMDQ: Roland Morris disability questionnaire; NRS: numerical rating scale.
Whole-body vibration and muscle fatigue have both been shown to delay the trunk muscle reflex response and increase trunk muscle activation, leading to an increased risk of low back injuries. ...However, the effects of whole-body vibration on previously fatigued trunk muscles have never been tested, despite studies showing that prolonged exposure to whole-body vibration can lead to muscle fatigue. The purpose of this research was to investigate the effects of muscle fatigue on muscle latency, muscle activation and perceived discomfort when exposed to whole-body vibration. The results showed that a fatigued muscle state resulted in increased muscle latency, muscle activation and perceived discomfort, which all escalate the risk of low back injuries. Additionally, the ISO 2631-1 comfort ratings did not increase with fatigue, showing a disconnect between these comfort ratings and the perceived discomfort ratings in a fatigued muscle state.
Practitioner summary: When exposed to whole-body vibration, fatigued back muscles result in delayed muscle contraction, higher overall muscle activation and increased perceived discomfort, all of which are known to increase low back injury risk. ISO 2631-1 comfort ratings are unable to increase with fatigue, showing a disconnect with perceived discomfort ratings.
Abbreviations: EMG: electromyography; EO: external oblique; IO: internal oblique; LE: lumbar erector spinae; LEO: left externaloblique; LIO: left internal oblique; LLE: left lumbar erector spinae; LTE: left thoracic erector spinae; MVC: maximum voluntarycontraction; REO: right external oblique; RIO: right internal oblique; RLE: right lumbar erector spinae; RTE: right thoracicerector spinae; SEAT: Seat Effective Amplitude Transmissibility; TE: thoracic erector spinae; WBV: whole body vibration
Natural rubber is considered an economic plant in Thailand and is used to manufacture many products. Foam back pillows have proven to have various benefits for the lower back. However, no study has ...compared the effects of foam and rubber pillows. Therefore, the current study aimed to compare the efficacy of foam and rubber pillows on transversus abdominis and internal oblique muscle fatigue, patient satisfaction, and discomfort scores during 60 min of prolonged sitting. Thirty healthy participants were invited to the study and randomized into three sitting conditions over three consecutive days. The three groups were as follows: control, foam pillow, and rubber pillow. Our results revealed that the discomfort score increased with the sitting time in all three groups (
< 0.05). The control group had the highest discomfort when compared to the rubber pillow group at 30 min (T4;
= 0.007) and 60 min (T7;
= 0.0001), as well as the foam pillow group at 60 min (T7;
= 0.0001). Participants were more satisfied sitting with the two types of back pillows at the initial time (T1;
= 0.0001) and at 60 min (T7;
= 0.0001) when compared with the control group. Furthermore, the participants were more satisfied with using rubber pillows rather than foam pillows throughout the sitting period (
= 0.0001). The control group experienced more transversus abdominis and internal oblique muscle fatigue at 60 min (T7) of sitting compared to the initial time (T1) (
= 0.038). Thus, sitting with pillow support can decrease deep trunk muscle fatigue, and using a pillow made from natural rubber may ensure greater satisfaction and less discomfort for the user.
Abstract. Purpose The external and internal abdominal muscles may be related to gait speed; however, this has not yet been elucidated. In this study, we aimed to clarify the relationship between gait ...speed and trunk muscle thickness in elderly individuals. Participants and Methods The participants were 12 elderly individuals (4 males and 8 females, mean age 83.4 years old, SD +- 0.5) that attend a day service center. We measured the 5 m free gait speed, the 5 m fastest gait speed, and the thickness of five trunk muscles (the rectus abdominis divided into three parts: upper, central, and lower, external oblique, internal oblique, transverse abdominis, and iliopsoas muscles). Results There were positive correlations between the free gait speed and the thickness of the lower rectus abdominis, internal oblique, and transverse abdominis muscles. There were also positive correlations between the fastest gait speed and the thickness of the lower rectus abdominis, internal oblique, and transverse abdominis muscles. Conclusion Incorporating muscle strength training of the lower rectus abdominis, internal oblique, and transverse abdominis muscles into existing lower limb muscle training protocols is important to effectively maintain the gait speed of elderly individuals.
Chronic low back pain (CLBP) is a highly prevalent disease with poorly understood underlying mechanisms. In particular, altered trunk muscle coordination in response to specific trunk tasks remains ...largely unknown.
We investigated the muscle synergies during 11 trunk movement and stability tasks in 15 healthy individuals (8 females and 7 males, aged 21. 3 (20.1-22.8) ± 0.6 years) and in 15 CLBP participants (8 females and 7 males, aged 20. 9 (20.2-22.6) ± 0.7 years) by recording the surface electromyographic activities of 12 back and abdominal muscles (six muscles unilaterally). Non-negative matrix factorization was performed to extract the muscle synergies.
We found six trunk muscle synergies and temporal patterns in both groups. The high similarity of the trunk synergies and temporal patterns in the groups suggests that both groups share the common feature of the trunk coordination strategy. We also found that trunk synergies related to the lumbar erector spinae showed lower variability in the CLBP group. This may reflect the impaired back muscles that reshape the trunk synergies in the fixed structure of CLBP. Furthermore, the higher variability of trunk synergies in the other muscle regions such as in the latissimus dorsi and oblique externus, which were activated in trunk stability tasks in the CLBP group, represented more individual motor strategies when the trunk tasks were highly demanding.
Our work provides the first demonstration that individual modular organization is fine-tuned while preserving the overall structures of trunk synergies and temporal patterns in the presence of persistent CLBP.
During level walking, lumbar spine is subjected to cyclic movements and intricate loading of the spinal discs and trunk musculature. This study aimed to estimate the spinal loads (T12–S1) and trunk ...muscles forces during a complete gait cycle.
Six men, 24–33years walk barefoot at self-selected speed (4–5km/h). 3D kinematics and ground reaction forces were recorded using a motion capturing system and two force plates, implemented in an inverse dynamic musculoskeletal model to predict the spinal loads and trunk muscles forces. Additionally, the sensitivity of the intra-abdominal pressure and lumbar segment rotational stiffness was investigated.
Peak spinal loads and trunk muscle forces were between the gait instances of heel strike and toe off. In L4–L5 segment, sensitivity analysis showed that average peak compressive, antero-posterior and medio-lateral shear forces were 130–179%, 2–15% and 1–6%, with max standard deviation (±STD) of 40%, 6% and 3% of the body weight. Average peak global muscles forces were 24–55% (longissimus thoracis), 11–23% (iliocostalis thoracis), 12–16% (external oblique), 17–25% (internal oblique) and 0–8% (rectus abdominus) of body weight whereas, the average peak local muscles forces were 11–19% (longissimus lumborum), 14–31% (iliocostalis lumborum) and 12–17% (multifidus). Maximum±STD of the global and local muscles forces were 13% and 8% of the body weight.
Large inter-individual differences were found in peak compressive and trunk muscles forces whereas the sensitivity analysis also showed a substantial variation.
Abdominal Hypopressive Training (AHT) provides postural improvement, and enhances deep trunk muscle activation. However, until recently, there was a lack of scientific literature supporting these ...statements. The major purpose of this study was to investigate the effect of AHT on posture control and deep trunk muscle function.
125 female participants aged 18-60 were randomly allocated to the Experimental Group (EG), consisting of two sessions of 30 min per week for 8 weeks of AHT, or the Control Group (CG), who did not receive any treatment. Postural control was measured with a stabilometric platform to assess the static balance and the activation of deep trunk muscles (specifically the Transverse Abdominal muscle (TrA)), which was measured by real-time ultrasound imaging.
The groups were homogeneous at baseline. Statistical differences were identified between both groups after intervention in the Surface of the Center of Pressure (CoP) Open-Eyes (S-OE) (
= 0.001, Cohen's d = 0.60) and the Velocity of CoP under both conditions; Open-Eyes (V-OE) (
= 0.001, Cohen´s d = 0.63) and Close-Eyes (V-CE) (
= 0.016, Cohen´s d = 0.016), with the EG achieving substantial improvements. Likewise, there were statistically significant differences between measurements over time for the EG on S-OE (
< 0.001, Cohen´s d = 0.99); V-OE (
= 0.038, Cohen´s d = 0.27); V-CE (
= 0.006, Cohen´s d = 0.39), anteroposterior movements of CoP with Open-Eyes (RMSY-OE) (
= 0.038, Cohen´s d = 0.60) and activity of TrA under contraction conditions (
< 0.001, Cohen´s d = 0.53).
The application of eight weeks of AHT leads to positive outcomes in posture control, as well as an improvement in the deep trunk muscle contraction in the female population.
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