Abdominal bracing during lifting alters trunk muscle activity and body kinematics

Multi-joint protective effects of lumbar brace on lumbar, hip, knee, and ankle in parachute landing with backpack load

There were high injury risks on lumbar and lower limb joints in parachuting landing, and the lumbar brace could protect lumbar. Besides, a backpack load was necessary in parachute landing and increased the injury risk. This study aimed to evaluate multi-joints protective effects of the lumbar brace on lumbar and lower limb joints in parachuting landing with the backpack load. Seven participants landed from a 120 cm height platform without and with a lumbar brace and without and with a 5-kg backpack load, respectively. Infrared makers were pasted on trunk, pelvis, and lower limb in order to build a multi-rigid-body model for calculating kinematic and kinetic parameters. The joint angular displacements of lumbar and ankle and the peak vertical ground reaction force were significantly decreased from 29.2 ± 9.2°, 45.2 ± 7.8°, and 14.7 ± 2.0 bodyweight to 21.6 ± 4.9° (p < 0.05), 39.0 ± 10.1° (p < 0.05) and 10.7 ± 1.3 bodyweight (p < 0.05) respectively by the lumbar brace with no backpack load, and the joint angular displacement of hip was significantly increased from 52.6 ± 7.2° to 68.3 ± 12.5° (p < 0.05). The joint angular displacement of lumbar and ankle were significantly decreased from 29.0 ± 5.0° and 53.8 ± 5.1° to 25.1 ± 5.2° (p < 0.05) and 48.5 ± 2.5° (p < 0.05) respectively by the lumbar brace with the backpack load, and the joint angular displacement of hip and knee were significantly increased from 60.1 ± 8.2° and 110.1 ± 9.3° to 69.7 ± 13.2° (p < 0.05) and 116.8 ± 5.8° (p < 0.05), respectively. The lumbar brace could provide the multi-joint protective effect by decreasing injuries of lumbar and ankle in landing both without and with the backpack load.

The effect of abdominal bracing on respiration during a lifting task: a cross-sectional study

BACKGROUND

Abdominal bracing is a maneuver widely used by rehabilitation specialists and sports trainers to improve spinal stability. This study aimed to investigate how lifting tasks with and without abdominal bracing affect the respiratory function of the diaphragm.

METHODS

M-mode ultrasonographic assessment of diaphragmatic motion combined with spirometry was performed on 31 healthy adults. Participants were asked to breathe continuously whilst lifting a load with spontaneous abdominal muscle contraction (natural loaded breathing) and abdominal bracing (AB loaded breathing).

RESULTS

Pearson's correlations revealed strong correlations between ultrasonography and spirometry measures (p < 0.001) for all types of breathing: tidal breathing (r = 0.709, r2 = 0.503), natural loaded breathing (r = 0.731, r2 = 0.534) and AB loaded breathing (r = 0.795, r2 = 0.632). Using paired-samples t-tests, the natural loaded breathing ultrasonography revealed more caudal diaphragm positions during inspiration (p < 0.001) but not during expiration (p = .101). Spirometry demonstrated lower lung volumes (L) at the end of inspiration and expiration (p < 0.001), with no changes in total lung volume (p = 0.06). The AB loaded breathing ultrasonography revealed more caudal diaphragm positions during inspiration (p = 0.002) but not during expiration (p = 0.05). Spirometry demonstrated lower lung volumes at the end of inspiration (p < 0.001), expiration (p = 0.002), and total lung volumes (p = 0.019).

CONCLUSION

This study demonstrated that abdominal bracing performed during a lifting task reduces lung volume despite an increase in diaphragmatic motion. Diaphragm excursions strongly correlate with lung volumes even under postural loading.

TRIAL REGISTRATION

The study was prospectively registered on 8 April 2021 at ClinicalTrials.gov with identification number NCT04841109.

Education to keep the abdomen relaxed versus contracted during pilates in patients with chronic low back pain: study protocol for a randomised controlled trial

BACKGROUND

Low back pain is a very common symptom frequently characterized as a biopsychosocial problem. This study aims to investigate the effectiveness of education to keep the abdomen relaxed versus contracted during Pilates exercises in patients with primary chronic low back pain.

METHODS

Two-group randomised controlled trial with allocation of parallel groups and intention-to-treat-analysis. This study will be conducted in Lavras, MG, Brazil. A total of 152 participants will be randomised into two groups that will be treated with Pilates exercises for 12 weeks (twice a week for 60 minutes). Recruitment began in May 2022. The control group will receive guidance on the specific activation of the center of strength (the powerhouse), while the experimental group will receive guidance to perform the exercises in a relaxed and smooth way. Primary outcomes will be pain intensity (Numeric Pain Rating Scale) and disability (Rolland-Morris Questionnaire) 12 weeks post randomisation. Secondary outcomes will be global improvement (Perception of Global Effect Scale) and specific functionality (Patient-specific Functional Scale). The outcomes will be analyzed using repeated-measure linear mixed models. The assessors were not considered blinded because the participants were not blinded, and outcomes were self-reported.

DISCUSSION

The findings of this study will help in clinical decision-making concerning the need to demand abdominal contraction during the exercises, understanding if it's a fundamental component for the effectiveness of the Pilates method for this population.

TRIAL REGISTRATION

This trial was prospectively registered in the Clinical Trials (NCT05336500) in April 2022.

Reliability of high-density surface electromyography for assessing characteristics of the thoracic erector spinae during static and dynamic tasks

PURPOSE

To establish intra- and inter-session reliability of high-density surface electromyography (HDEMG)-derived parameters from the thoracic erector spinae (ES) during static and dynamic goal-directed voluntary movements of the trunk, and during functional reaching tasks.

METHODS

Twenty participants performed: 1) static trunk extension, 2) dynamic trunk forward and lateral flexion, and 3) multidirectional functional reaching tasks on two occasions separated by 7.5 ± 1.2 days. Muscle activity was recorded bilaterally from the thoracic ES. Root mean square (RMS), coordinates of the barycentre, mean frequency (MNF), and entropy were derived from the HDEMG signals. Reliability was determined with intraclass correlation coefficient (ICC), coefficient of variation, and standard error of measurement.

RESULTS

Good-to-excellent intra-session reliability was found for all parameters and tasks (ICC: 0.79-0.99), whereas inter-session reliability varied across tasks. Static tasks demonstrated higher reliability in most parameters compared to functional and dynamic tasks. Absolute RMS and MNF showed the highest overall reliability across tasks (ICC: 0.66-0.98), while reliability of the barycentre was influenced by the direction of the movements.

CONCLUSION

RMS and MNF derived from HDEMG show consistent inter-session reliability in goal-directed voluntary movements of the trunk and reaching tasks, whereas the measures of the barycentre and entropy demonstrate task-dependent reliability.

NEUROMUSCULAR MECHANISMS AND EFFECTS OF CORE STABILIZATIONS ON TRUNK AND HIP MUSCLE ACTIVITY DURING LIFTING MOVEMENT

While the presence of lumbopelvic-hip stabilization has been provided as an importance component of the intra-abdominal pressure and dynamic spinal stabilization prior to movement, no previous study has investigated the effects in nonsymptomatic adults. This study investigated neuromuscular mechanisms and effects by comparing the natural core stabilization (NCS), abdominal bracing stabilization (ABS), and coordinated core stabilization (CCS) techniques in nonsymptomatic adults during lifting movement. A convenience sample of 40 nonsymptomatic adults (mean [Formula: see text] standard deviation, [Formula: see text]; 27 males, 13 females) were randomized into the NCS, ABS, and CCS techniques during lifting movement. The clinical outcomes included the deep and local (transverse abdominis (TrA), internal oblique (IO), and gluteus maximus (Gmax)) and superficial and global muscle (thoracic erector spinae (TES), lumbar erector spinae (LES), and external oblique (EO)) activation and balance ratios (IO/LES and Gmax/LES) and onset time co-activation ratios (IO/LES and Gmax/LES). One-way repeated-measures analysis of variance (ANOVA) and Bonferroni correction revealed that the IO/LES and Gmax/LES balance and activation ratios were greater in CCS than in NCS and ABS. The onset time co-activation ratio was improved in CCS as compared with NCS and ABS, and ABS dropped equally inversely to NCS. Our results provide novel therapeutic evidence that CCS-based lifting movement is more balanced or coordinated in terms of neuromuscular control than the other techniques and may be used as an alternative exercise for core stabilization.

Flexed lumbar spine postures are associated with greater strength and efficiency than lordotic postures during a maximal lift in pain-free individuals

BACKGROUND

Inspite of common lifting advice to maintain a lordotic posture, there is debate regarding optimal lumbar spine posture during lifting. To date, the influence of lumbar posture on trunk muscle recruitment, strength and efficiency during high intensity lifting has not been fully explored.

RESEARCH QUESTION

How do differences in lumbar posture influence trunk extensor strength (moment), trunk muscle activity, and neuromuscular efficiency during maximal lifting?

METHODS

Twenty-six healthy participants adopted three lumbar postures (maximal extension (lordotic), mid-range (flat-back), and fully flexed) in a free lifting position. Motion analysis and force measurements were used to determine the back extensor, hip and knee moments. Surface electromyography (EMG) of three trunk extensors and the internal obliques were recorded. Neuromuscular efficiency (NME) was expressed as a ratio of normalised extensor moment to normalised EMG.

RESULTS

Significantly higher back extensor moments were exerted when moving from an extended to mid-range, and from a mid-range to fully flexed lumbar posture. This was accompanied by a decrease in activity across all three back extensor muscles (P < 0.001) resulting in a higher NME of these muscles in more flexed postures. Change in lumbar posture did not influence hip or knee moments or internal oblique activation.

SIGNIFICANCE

A flexed-back posture is associated with increased strength and efficiency of the back muscles compared to a lordotic posture. These findings further question the manual handling advice to lift with a lordotic lumbar spine.

The Effectiveness of Lumbar Supports

Nonspecific back pain is a common complaint, especially among older people. Traditionally, nonspecific back pain has been associated with heavy physical activities. However, static activities such as prolonged sitting and standing are contributing factors to nonspecific lumbar pain as well. Lumbar orthoses, such as belts, have been used for heavy physical activity to alleviate or even prevent back pain; however, studies have been inconclusive as to their effectiveness. Furthermore, the use of lumbar orthosis for prolonged sitting and standing is questionable. This case study and review examines the general effectiveness of lumbar orthosis for a variety of activities, including prolonged standing and sitting. The findings provide implications for orthopaedic nurses in occupational settings.

Trunk muscle function and pelvic alignment associated with the presence of pain in higher education students: a cross-sectional study

Abstract Introduction: The protective role of muscles in the passive structures of the spine means that their stability and consequent maintenance are associated with pain, especially in the region of the lumbo-pelvic-hip complex. Objective: To determine the prevalence of pain and its association with muscle deficits in higher education students. Method: Descriptive, observational, cross-sectional study that evaluated 120 university students through questionnaires (sample characterization, Nordic musculoskeletal symptoms, pain visual analogue scale and international physical activity). Trunk muscle strength and bridge tests with unilateral knee extension (pelvic alignment) were performed. Results: A high prevalence of pain was found in the lower back (58.41%). There was no association between the presence of pain, muscle strength and pelvic alignment (p> 0.05). There was an association between the trunk extension and pelvic tilt tests (p = 0.009). Conclusion: A high prevalence of low back pain, poor performance in the trunk muscle endurance tests and mild and moderate pelvic misalignment were identified. There was no association between pain, trunk muscle weakness and pelvic misalignment. There was an association between pelvic misalignment and trunk extensor muscle weakness.

Maintaining Lumbar Spine Stability: A Study of the Specific and Combined Effects of Abdominal Activation and Lumbosacral Orthosis on Lumbar Intrinsic Stiffness

BACKGROUND

Two potential interventions for enhancing lumbar stability are to actively increase abdominal muscle activity, either through the abdominal drawing-in maneuver (ADIM) or bracing, and passively increase lumbar stiffness using a lumbosacral orthosis (LSO).

OBJECTIVE

To compare the increase in lumbar stiffness after 2 active interventions (ADIM versus bracing) and 1 passive intervention (LSO), and to evaluate the combined effect of active (abdominal bracing) and passive interventions.

METHODS

In this experimental and comparative study, lumbar stiffness, a surrogate measure of lumbar stability, was estimated in 25 healthy individuals during 7 trunk perturbation conditions: (1) control, (2) ADIM, (3) bracing at 5% of right external oblique maximal voluntary activation (5% bracing), (4) bracing at 10% of right external oblique maximal voluntary activation (10% bracing), (5) LSO, (6) LSO plus 5% bracing, and (7) LSO plus 10% bracing. Electromyographic biofeedback of the external oblique was provided on a monitor, while ultrasound was used for the ADIM to ensure a sustained contraction of the transversus abdominis.

RESULTS

The ADIM, 5% bracing, and 10% bracing active interventions generated comparable lumbar stiffness. However, considering that bracing can range from 10% to 20%, it may be superior to hollowing, as further estimated with a mixed-effect statistical model. Combining bracing and an LSO resulted in an additive effect on lumbar stiffness.

CONCLUSION

Bracing and ADIM produced comparable lumbar stiffness, as they were performed at the same overall abdominal activation levels (5% and 10% maximal voluntary activation). The independent effects of bracing and LSO raises the possibility of combining these interventions in some circumstances. J Orthop Sports Phys Ther 2019;49(4):262-271. Epub 18 Jan 2019. doi:10.2519/jospt.2019.8565.