Age and gender related neuromuscular changes in trunk flexion-extension

Age-dependent flexion relaxation phenomenon in chronic low back pain patients

Background

The flexion relaxation phenomenon (FRP) is characterized by suddenly reduced paraspinal muscle activity during full flexion. Previous studies showed significant differences in FRP and flexion angles in chronic low back pain (cLBP) patients compared to individuals without back pain (no-BP). However, the relationship between FRP and flexion angles remains insufficiently understood in older populations. Thus, this study investigated the relationship between FRP and flexion angles concerning to the age and presence of cLBP.

Methods

Forty no-BP subjects (20m/20f; mean age 41.5 years) and thirty-eight cLBP patients (19m/19f; mean age 43.52 years) performed maximum full upper body flexion task. Electromyographic (EMG) measurements were conducted to assess the activity of lumbar erector spinae (ESL), thoracic erector spinae (EST), and multifidus (MF). Lumbar, thoracic, and pelvic angles at the onset (OnsetL/T/P) and offset of the FRP (OffsetL/T/P) and maximum trunk inclination (MaxL/T/P) were calculated. The FRP was evaluated using a flexion relaxation ratio (FRR).

Results

cLBP patients showed smaller FRR in MF and right ESL compared to no-BP individuals (p < 0.05), while no differences were found in flexion angles between two groups. Subjects over 40 showed smaller FRR in MF and ESL, and smaller flexion angles on OffsetL and MaxL (p < 0.05). Age-related analysis in the cLBP group revealed that patients over 40, compared to younger ones, had smaller FRR in MF and ESL, and smaller values in all thoracic and lumbar flexion angles (p < 0.05). While in no-BP group, significant larger flexion angles in OnsetL and OffsetT (p < 0.05) were observed in participants over 40. Pain-related analysis in the older group revealed that the cLBP patients, compared to no-BP individuals, had smaller FRR in right MF and right ESL, and smaller values in all lumbar and thoracic flexion angles (p < 0.05), while in younger group, there were no significant pain-related differences in FRR, with larger values in all lumbar flexion angles (p < 0.05).

Conclusion

Our findings indicate a reduction or absence of FRP in cLBP patients compared to no-BP individuals, with age being a significant factor as those over 40 showed smaller FRP and flexion angles compared to younger individuals.

Application of restorative neurostimulation for chronic mechanical low back pain in an older population with 2-year follow up

INTRODUCTION

Data on the Medicare-aged population show that older patients are major consumers of low back pain (LBP) interventions. An effective approach for patients with mechanical LBP that has been refractory to conservative management is restorative neurostimulation. The efficacy of restorative neurostimulation has been demonstrated in multiple prospective studies, with published follow-up over 4 years, showing a consistent durable effect.

METHODS

To further examine the effect of restorative neurostimulation in an older demographic, data from three clinical studies were aggregated: ReActiv8-B prospectively followed 204 patients, ReActiv8-C study prospectively followed 87 patients and ReActiv8-PMCF prospectively followed 42 patients.Two hundred and sixty-one patients were identified with complete 2-year follow-up and divided into cohorts of equal size based of age quartiles.At 2 years from device activation, patients in either cohort were classified by change in disability (Oswestry Disability Index (ODI)) or change in pain score(NRS/VAS) and assessed as proportion of patients per group at each time point. Additionally, health-related quality of life (HRQoL) (EQ5D-5L) was longitudinally compared with baseline. Differences in proportions were assessed using χ2 and continuous variables by repeated measures analysis of variance.

RESULTS

The oldest quartile (n=65) had a median age of 60 (56-82) years compared with the entire population (n=261) who had a median age of 49 (22-82) years. The completer analysis on patients with 2 years of continuous data showed improvement of a 50% in pain was achieved by 62% and 65% and a 15-point ODI improvement in 48% and 60% in the oldest quartile and entire population, respectively. HRQoL (EuroQol 5-Dimension) improved from baselines of 0.568 and 0.544 to 0.763 and 0.769 in the oldest quartile and entire population respectively. All age quartiles improved statistically and clinically over baseline.

CONCLUSIONS

This aggregate analysis of three independent studies provides insight into the performance of restorative neurostimulation in an older population. Patients derived significant and clinically meaningful benefit in disability, pain and HRQoL. When compared with a similarly indicated cohort of younger patients, there were no statistically or clinically significant differences.

Non-Specific Low Back Pain: An Inductive Exploratory Analysis through Factor Analysis and Deep Learning for Better Clustering

Non-specific low back pain (NSLBP) is a significant and pervasive public health issue in contemporary society. Despite the widespread prevalence of NSLBP, our understanding of its underlying causes, as well as our capacity to provide effective treatments, remains limited due to the high diversity in the population that does not respond to generic treatments. Clustering the NSLBP population based on shared characteristics offers a potential solution for developing personalized interventions. However, the complexity of NSLBP and the reliance on subjective categorical data in previous attempts present challenges in achieving reliable and clinically meaningful clusters. This study aims to explore the influence and importance of objective, continuous variables related to NSLBP and how to use these variables effectively to facilitate the clustering of NSLBP patients into meaningful subgroups. Data were acquired from 46 subjects who performed six simple movement tasks (back extension, back flexion, lateral trunk flexion right, lateral trunk flexion left, trunk rotation right, and trunk rotation left) at two different speeds (maximum and preferred). High-density electromyography (HD EMG) data from the lower back region were acquired, jointly with motion capture data, using passive reflective markers on the subject's body and clusters of markers on the subject's spine. An exploratory analysis was conducted using a deep neural network and factor analysis. Based on selected variables, various models were trained to classify individuals as healthy or having NSLBP in order to assess the importance of different variables. The models were trained using different subsets of data, including all variables, only anthropometric data (e.g., age, BMI, height, weight, and sex), only biomechanical data (e.g., shoulder and lower back movement), only neuromuscular data (e.g., HD EMG activity), or only balance-related data. The models achieved high accuracy in categorizing individuals as healthy or having NSLBP (full model: 93.30%, anthropometric model: 94.40%, biomechanical model: 84.47%, neuromuscular model: 88.07%, and balance model: 74.73%). Factor analysis revealed that individuals with NSLBP exhibited different movement patterns to healthy individuals, characterized by slower and more rigid movements. Anthropometric variables (age, sex, and BMI) were significantly correlated with NSLBP components. In conclusion, different data types, such as body measurements, movement patterns, and neuromuscular activity, can provide valuable information for identifying individuals with NSLBP. To gain a comprehensive understanding of NSLBP, it is crucial to investigate the main domains influencing its prognosis as a cohesive unit rather than studying them in isolation. Simplifying the conditions for acquiring dynamic data is recommended to reduce data complexity, and using back flexion and trunk rotation as effective options should be further explored.

Modified lumbo-pelvic exercise to alleviate mild stress urinary incontinence in middle-aged females

Urinary incontinence is one of the common clinical problems of females passing middle age. Traditional pelvic floor muscle training to alleviate urinary incontinence is too dull and unpleasant. Therefore, we were motivated to purpose a modified lumbo-pelvic exercise training incorporating simplified dancing components with pelvic floor muscle training. The objective of this study was to evaluate the 16-week modified lumbo-pelvic exercise program that incorporated dance and abdominal drawing-in maneuvers. Middle-aged females were randomly assigned into the experimental (n = 13) and control (n = 11) groups. Compared to the control group, the exercise group significantly reduced body fat, visceral fat index, waistline, waist-hip ratio, perceived incontinence score, frequency of urine leakage, and pad testing index (p < 0.05). In addition, there were significant improvements in pelvic floor function, vital capacity, and muscle activity of the right rectus abdominis (p < 0.05). This indicated that the modified lumbo-pelvic exercise program can promote benefits of physical training and alleviate urinary incontinence in middle-aged females.

The association between different physical activity levels and flexion-relaxation phenomenon in women: a cross-sectional study

BACKGROUND

To investigate whether the flexion-relaxation phenomenon differs in women with different physical activity levels.

METHODS

Seventy-two subjects were recruited for this study. The electromyographic activity of the erector spinae and multifidus muscles was recorded during a flexion task using a surface electromyographic device. The flexion-relaxation and extension-relaxation ratios were calculated. Participants were classified into different physical activity level groups based on their responses to the International Physical Activity Questionnaire. A Welch analysis of variance was conducted to compare the flexion-relaxation ratio and extension-relaxation ratio between groups.

RESULTS

A significant difference in the flexion-relaxation and extension-relaxation ratio was observed in both the erector spinae and multifidus muscles between different levels of physical activity.

CONCLUSIONS

In this study, we observed that female participants with high levels of physical activity showed a more pronounced flexion-relaxation phenomenon compared to those with moderate and low levels of physical activity. No significant difference was found between moderate and low physical activity levels. The findings of our study highlight the association between physical activity and the mechanics of the spinal stabilising muscles.

Analysis of Trunk Neuromuscular Activation During Equine-Assisted Therapy in Older Adults

The three-dimensional movement of the horse in physical therapy is a valuable kinesio-therapeutic phenomenon that simultaneously affects several body systems, including particularly the neuromuscular system. However, the effects of equine-assisted services (EAS) on neuromuscular activation patterns in older adults have not been thoroughly investigated. In this study, we evaluated the impact of a 10-weeks EAS program on trunk muscles in older adults who used a saddle and placed their feet in stirrups for the first 15 minutes and out of stirrups for the remaining 15 minutes of 30-minute EAS sessions. We gathered electromyographic (EMG) data of the trunk muscles five times each on the first, fifth, and 10th sessions: pre-EAS and post-EAS on a stationary horse and at 1-minute, 15-minutes, and 30-minutes on a horse in motion. Participants were 20 adults, aged 60-79 years. We analyzed normalized EMG data with 5 (session time) by 3 (session number) analyses of variance (ANOVAs) with repeated measures and with Bonferroni's testing (p ≤ .05). There was a significant difference over the number of interventions for the right thoracic paravertebral muscle (p = .025) and session time effect for the left trapezius (p = .042), right thoracic paravertebral (p < .001), right and left multifidus (p < .001), and right and left rectus abdominis muscles (p < .001). Thus, trunk muscles in older adults showed complex neuromuscular activation synchronized with the horse's movement, which was influenced by session time and number of interventions. The practical implication of these findings is that EAS can reduce fall risk among elderly adults of both sexes.

Immediate Effect of Lumbosacral Orthosis and Abdominal Drawing-In Maneuver on Postural Control in Adults With Nonspecific Chronic Low Back Pain

OBJECTIVE

The purpose of this study was to examine the immediate effects of lumbosacral orthosis and the abdominal drawing-in maneuver on the trunk postural control of adults with chronic low back pain compared with asymptomatic controls during 1-legged and semi-tandem stances.

METHODS

An experimental and comparative study (cross-sectional design) was conducted in a laboratory setting. Twenty adults with chronic low back pain and 20 asymptomatic controls randomly performed 2 postural balance tasks over a force platform, considering 3 experimental conditions: (1) natural posture (baseline-control), (2) lumbosacral orthosis, and (3) abdominal drawing-in maneuver. Linear variables (mean amplitude, ellipse area, and sway velocity) derived from the center of pressure were computed, and 2-way analysis of variance (group × condition) for repeated measures were conducted.

RESULTS

No group × condition interactions (.139 ≤ P ≤.938) were detected in any center of pressure parameters. No condition effect was detected, but a group effect (P = .042) was observed for 1 center of pressure parameter. The chronic low back pain group presented with a lower mean anteroposterior center of pressure amplitude than asymptomatic controls (∆ = 0.31 ± 0.66 cm [95% confidence interval, 0.05-0.56], P = .019) during the semi-tandem stance balance task.

CONCLUSION

Neither lumbosacral orthosis nor the abdominal drawing-in maneuver showed immediate improvement in trunk postural control in any group. Thus, clinicians should not expect immediate benefits or improvements yielded by lumbosacral orthosis or the abdominal drawing-in maneuver when patients with chronic low back pain undergo these interventions.

Effect of Age on Thoracic, Lumbar, and Pelvis Coordination During Trunk Flexion and Extension

The purpose of this study was to investigate normative and age-related differences in trunk and pelvis kinematics and intersegmental coordination during sagittal plane flexion–extension. Trunk and pelvis kinematics were recorded while 76 participants performed a maximal range of motion task in the sagittal plane. Cross-correlation was calculated to determine the phase lag between adjacent segment motion, and coupling angles were calculated using vector coding and classified into one of 4 coordination patterns: in-phase, antiphase, superior, and inferior phase. A 2-way mixed-model multivariate analysis of variance was used to compare lumbar spine and pelvis angular kinematics, phase lags, and cross-correlation coefficients between groups. Young participants exhibited greater trunk range of motion compared with middle-aged participants. The lumbar spine and pelvis were predominantly rotating with minimum phase lag during flexion and extension movement for both age groups, and differences in coordination between the groups were seen during hyperextension and return to upright position. In conclusion, middle-aged adults displayed lower range of motion but maintained similar movement patterns to young adults, which could be attributed to protective mechanisms. Healthy lumbar and pelvis movement patterns are important to understand and need to be quantified as a baseline, which can be used to develop rehabilitation protocols for individuals with spinal ailments.

Characteristics of Forces at the Clinician–Patient and Patient–Table Interfaces During Thoracic Spinal Manipulation in Asymptomatic Adults Are Consistent With Deformable Body Models

Investigating all forces exerted on the patient’s body during high-velocity, low-amplitude spinal manipulative therapy (SMT) remains fundamental to elucidate how these may contribute to SMT’s effects. Previous conflicting findings preclude our understanding of the relationship between SMT forces acting at the clinician–patient and patient–table interfaces. This study aimed to quantify forces at the clinician–participant and participant–table interfaces during thoracic SMT in asymptnomatic adults. An experienced clinician provided a posterior to anterior SMT centered to T7 transverse processes using predetermined force–time characteristics to 40 asymptomatic volunteers (20 females; average age = 27.2 [4.9] y). Forces at the clinician–participant interface were recorded by triaxial load cells; whereas, forces at the participant–table interface were recorded by the force-sensing table technology. Preload force, total peak force, time to peak, and loading rate at each interface were analyzed descriptively. Total peak vertical forces at the clinician–participant interface averaged 532 (71) N while total peak forces at the participant–table interface averaged 658 (33) N. Forces at the participant–table interface were, on average, 1.27 (0.25) times larger than the ones at the clinician–participant interface. Larger forces at the participant–table interface compared with the ones at the clinician–participant interface during thoracic SMT are consistent with mathematical models developed to investigate thoracic impact simulating a dynamic force-deflection response.

Relationship between low back pain and lumbar and hip joint movement in desk workers

[Purpose] The study aimed to determine the relationship between low back pain and lumbar and hip movement in desk workers with chronic non-specific low back pain, in order to obtain basic data regarding measures for preventing low back pain in desk workers. [Participants and Methods] The study included 10 desk workers (all female, age: 47.1 ± 6.0 years). The following measurements were recorded: numerical rating scale score for pain assessment at the time of maximum forward and backward bending of the trunk while standing, and the amount of movement of the trunk and the lumbar and hip joint. The ratio of the lumbar and hip joint movements during maximum forward and backward bending of the trunk was calculated. [Results] For maximum forward and backward bending of the trunk, a positive correlation between the numerical rating scale score and the ratio of movement for the lumbar and a negative correlation with that of the hip joint were noted. [Conclusion] Moving the hip joint while suppressing excessive lumbar movement is one of the measures for preventing low back pain in desk workers.

Association between the trunk muscle function performance and the presence of vertebral fracture in older women with low bone mass

BACKGROUND

Despite the clinical importance, it has remained unclear which changes in the trunk muscle function parameters are more associated with the presence of vertebral fracture (VF).

AIMS

The aim of this study was to verify the association between the trunk muscle function performance and the presence of VF in older women with low bone mass. The secondary aim was to evaluate the correlation between trunk muscle function and both fall history and muscle mass.

METHODS

This cross-sectional study was composed by 94 women over 60 years within value of T-Score lumbar spine BMD  <- 1.0 DP. Multidimensional evaluations were performed: appendicular skeletal muscle mass index (ASMI) was determined by the total body DEXA; the radiographic evaluations measured the degree of thoracic kyphosis and classification of VF. The trunk muscle function parameters, such as peak torque (PT), rate of torque development (RTD) and torque steadiness (TS) were evaluated by isokinetic dynamometer. The trunk muscle endurance was evaluated by the timed loaded standing test. The adjusted multivariate logistic regression model and multivariate linear regression were performed to verify the association between the variables studied.

RESULTS

The results showed that the trunk muscle function parameter with greater association with the presence of VF is TS extensors (OR = 1.70; p < 0.001). The other two significant muscle parameters were: RTD₃₀ flexors (OR = 0.31; p = 0.033) and PT extensors (OR = 0.13; p = 0.009). No statistical association was found between the presence of VF and the ASMI and trunk muscle endurance. No correlation between trunk muscle function and fall history was observed. There was a weak correlation between ASMI and extensor PT (R² = 0.21; p = 0.027) and extensor RTD₃₀ (R² = 0.21; p = 0.026).

CONCLUSIONS

This study demonstrated that deficit in trunk muscle function has shown a strong association with the presence of VF, highlighting issues heretofore unexplored regarding the association between VF with muscle power and motor control.

Flexion-Relaxation Ratio Asymmetry and Its Relation With Trunk Lateral ROM in Individuals With and Without Chronic Nonspecific Low Back Pain

STUDY DESIGN

A cross-sectional comparative study.

OBJECTIVE

The present study aimed to investigate the relationship between the FR phenomenon asymmetry of lumbar muscles and trunk lateral range of motion (ROM) asymmetry in nonspecific chronic low back pain (NSCLBP) patients.

SUMMARY OF BACKGROUND DATA

Imbalance in trunk muscle activation between right and left sides can induce pain by loading the spine incorrectly, especially in patients with NSCLBP. A previous study reported a greater asymmetry in the FR phenomenon of the erector spinae in NSCLBP patients than in asymptomatic participants (APs). Imbalance of muscle properties, such as trunk ROM, has been suggested as a possible cause of this observed asymmetry.

METHODS

Twenty-eight NSCLBP patients and 22 AP performed 3 standing maximal trunk flexions. Surface electromyography was recorded bilaterally for erector spinae longissimus and lumbar multifidus. A FR ratio was calculated for each muscle. The fingertip-to-thigh test was performed to assess trunk lateral ROM. Each parameter's asymmetry was calculated as the absolute difference between right and left sides.

RESULTS

NSCLBP patients present a significantly lower trunk lateral ROM than AP. FR ratio asymmetry of the erector spinae was significantly greater in NSCLBP patients than in AP (P < 0.05). FR ratio asymmetry of the multifidus and trunk lateral ROM asymmetry were not significantly different between groups. Significant correlation (r = 0.49) between FR ratio asymmetry of erector spinae and trunk lateral ROM asymmetry was observed only for patients with NSCLBP.

CONCLUSION

The present findings showed that FR ratio asymmetry of erector spinae longissimus is moderately correlated with trunk lateral ROM asymmetry. In addition, the results confirmed that patients with NSCLBP present a reduced trunk lateral ROM, a FR ratio asymmetry of the erector spinae which is correlated with trunk rotation. These findings suggested an imbalance spine loading which can contribute to the persistence of pain.

LEVEL OF EVIDENCE

3.

Characteristic Movement of the Ribs, Thoracic Vertebrae while Elevating the Upper Limbs - Influences of Age and Gender on Movements

Background:

The rib cage, such as the thoracic spine and ribs, influences glenohumeral mobility and the development of shoulder disorders.

Objective:

To evaluate movements of the ribs, thoracic vertebrae during bilateral arm elevation and to clarify the characteristic influences of age and gender.

Methods:

Subjects comprised 33 healthy individuals divided into a young group (10 males, 7 females; mean age, 25 years) and a middle-aged group (8 males, 8 females; mean age, 52 years). Chest CT was performed with two arm positions: arms hanging downwards; and arms elevated at 160°. Images were three-dimensionally reconstructed to evaluate rib movement, extension angle of thoracic vertebrae.

Results:

Maximal movement was observed at the fifth rib, and rib movement decreased with increasing distance from the fifth rib in both the groups. In males, movement of the second to fourth ribs was smaller in the middle-aged group than in the young group (p < 0.05). Movement of the first to ninth ribs was smaller in females than in males (p < 0.05). No significant difference in the extension angle of the thoracic vertebrae was found.

Conclusion:

Fifth rib movement is the largest among all ribs during bilateral arm elevation. Reduction of upper rib movement initially arises as an age-related degradation in males. Women exhibit less rib movement during bilateral arm elevation.

Heel-Raised Foot Posture Does Not Affect Trunk and Lower Extremity Biomechanics During a Barbell Back Squat in Recreational Weight lifters

Lee, S-P, Gillis, CB, Ibarra, JJ, Oldroyd, DF, and Zane, RS. Heel-raised foot posture does not affect trunk and lower extremity biomechanics during a barbell back squat in recreational weight lifters. J Strength Cond Res 33(3): 606-614, 2019-It is claimed that weightlifting shoes with a raised heel may lead to a more upright trunk posture, and thus reduce the risk of back injuries during a barbell back squat. These proclaimed biomechanical effects have not been thoroughly investigated. The purpose of this study was to compare trunk and lower extremity biomechanics during barbell back squats in three foot postures. Fourteen recreational weight lifters (7 men and 7 women) between the ages of 18 and 50 years performed barbell back squats in three conditions (barefoot on a flat surface, barefoot on a heel-raised platform, and wearing heel-raised weightlifting shoes) at 80% of their 1 repetition maximum. Surface electromyography was used to assess the activation of the knee extensors and paraspinal muscles at L3 and T12 spinal levels. A 3D motion capture system and an electrogoniometer recorded the kinematics of the thoracic spine, lumbar spine, and knee during the back squat to a depth where the hip was at least at the same level to the knee. Results indicated that none of the heel-raised foot postures significantly affected trunk and lower extremity muscle activation (thoracolumbar paraspinal [p = 0.52], lumbar paraspinal [p = 0.179], knee extensor [p = 0.507]) or the trunk angles (thoracolumbar spine [p = 0.348], lumbar spine [p = 0.283]) during the squat. Our results demonstrated that during barbell back squats, heel-raised foot postures do not significantly affect spinal and knee extensor muscle activations, and trunk and knee kinematics. Heel-raised weightlifting shoes are unlikely to provide significant protection against back injuries for recreational weight lifters during the barbell back squat.

Effect of age and sex on lumbar lordosis and the range of motion. A systematic review and meta-analysis

Lumbar lordosis (LL) and the range of motion (RoM) are important physiological measurements when initiating any diagnosis and treatment plan for patients with low back pain. Numerous studies reported differences in LL and the RoM due to age and sex. However, these findings remain contradictory. A systematic review and meta-analysis were performed to synthesize mean values and the differences in LL and the RoM because of age and sex. The quality assessment tool for quantitative studies was applied to assess the methodological quality of the studies included. We identified 2372 papers through electronic (2309) and physical (63) searches. We assessed 218 full-text studies reporting measurements of LL or the RoM. In total, 65 studies were included, and a normative database for LL and the RoM is provided as supplementary material. Among these, 11 were included in the meta-analysis. LL and the RoM displayed non-monotonic variations with significant age and sex differences. Young females showed a significantly greater LL and the range of extension (RoE), whereas young males exhibited a greater range of flexion (RoF). Sex differences in the range of lateral bending (RoLB) were small but were significant for the axial rotation (RoAR). For the RoF, RoE and RoLB, differences because of age were significant among most of the age groups in both sexes, whereas for the RoAR, differences were significant only between the 20s vs the 30s-40s (males) and 40s vs 50s (females). Significant differences because of age/sex were identified. However, the age-dependent reduction in LL and the RoM was non-monotonic and differed in both sexes. These findings will help to better distinguish between functional deficits caused by spinal disorders and natural factors/conditions related to age and sex.

Standard reference values of the upper body posture in healthy young female adults in Germany: an observational study

OBJECTIVE

Classifications of posture deviations are only possible compared with standard values. However, standard values have been published for healthy male adults but not for female adults.

DESIGN

Observational study.

SETTING

Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University Frankfurt/Main.

PARTICIPANTS

106healthy female volunteers (21-30 years old; 25.1±2.7 years) were included. Their body weight ranged from 46 to 106 kg (60.3±7.9 kg), the heights from 1.53 to 1.82 m (1.69±0.06 m) and the body mass index from 16.9 kg/m² to 37.6 kg/m² (21.1±2.6 kg/m²).

OUTCOME MEASURES

A three-dimensional back scan was performed to measure the upper back posture in habitual standing. The tolerance ranges and CI were calculated. Group differences were tested by the Wilcoxon Mann-Whitney U test.

RESULTS

In normal posture, the spinal column was marginally twisted to the left, and the vertebrae were marginally rotated to the right. The kyphosis angle is larger than the lumbar angle. Consequently, a more kyphotic posture is observed in the sagittal plane. The habitual posture is slightly scoliotic with a rotational component (scapular depression right, right scapula marginally more dorsally, high state of pelvic right, iliac right further rotated anteriorly).

CONCLUSIONS

Healthy young women have an almost ideally balanced posture with minimal ventral body inclination and a marginal scoliotic deviation. Compared with young males, women show only marginal differences in the upper body posture. These values allow a comparison to other studies, both for control and patient data, and may serve as guideline in both clinical practice and scientific studies.

Multi-segmental thoracic spine kinematics measured dynamically in the young and elderly during flexion

In contrast to the cervical and lumbar region, the normal kinematics of the thoracic spine have not been thoroughly investigated. The aim of this study was to characterize normal multi-segmental continuous motion of the whole thoracolumbar spine, during a flexion maneuver, in young and elderly subjects. Forty-two healthy volunteers were analyzed: 21 young (age=27.00±3.96) and 21 elderly (age=70.1±3.85). Spinal motion was recorded with a motion-capture system and analyzed using a 3rd order polynomial function to approximate spinal curvature throughout the motion sequence. The average motion profiles of the two age groups were characterized. Flexion timing of the thoracic region of the spine, as compared to the lumbar spine and hips, was found to be different in the two age groups (p=0.011): a delayed/sequential motion type was observed in most of the young, whereas mostly a simultaneous motion pattern was observed in the elderly subjects. A similar trend was observed in flexion of the lower thoracic segments (p=0.017). Differences between age groups were also found for regional and segmental displacements and velocities. The reported characterization of the thoracic spine kinematics may in the future support identification of abnormal movement or be used to improve biomechanical models of the spine.

Activity of Erector Spinae During Trunk Forward Bending and Backward Return: The Effects of Age

Electromyography (EMG)-based measures of the trunk muscles behavior have been used for objective assessment of biomechanical impairments in patients with low back pain (LBP); yet the literature on normal age-related differences in such measures is scant. A cross-sectional study was designed to assess age-related differences in activity of trunk extensors during forward bending and backward return. Sixty asymptomatic individuals were recruited to form five gender-balanced age groups between 20 and 70 years old. Participants completed two sets of trunk forward bending and backward return task using self-selected and fast motion paces. For bending and return phases of each task, the normalized lumbar flexion angles corresponding to different event times of erector spinae activity along with the peak normalized and non-normalized EMG activities of erector spinae were calculated. The mean normalized and non-normalized EMG activities of erector spinae during the entire task also were calculated. There was no age-related difference in normalized lumbar flexion angles corresponding to different event times of erector spinae activity. However, the peak normalized EMG activity during forward bending and backward return as well as the mean normalized EMG activity during the entire task were found to be larger in older vs. younger individuals. Given the suggested unreliability of normalized EMG in elders and considering that we did not find any age-related differences in non-normalized EMG activity of erector spinae, our results do not strongly support the existence of normal age-related differences in EMG profile of erector spinae during forward bending and backward return. Therefore, when interpreting EMG-based measures of trunk muscles behavior for identification of biomechanical impairment in patients with LBP, potential abnormalities in EMG activity of trunk muscles may not be attributed to patient's age.

The Role of Trunk Musculature in Osteoporotic Vertebral Fractures: Implications for Prediction, Prevention, and Management

This review examines the current evidence for associations between vertebral fractures (VFx), the most common type of fracture in older adults, and trunk muscles, which are intimately tied to spinal loading and function. Individuals with prevalent VFxs have more fat infiltration in the trunk muscles, lower trunk extension strength, and altered muscle activation patterns. However, no longitudinal studies have examined whether assessment of trunk muscle can contribute to prediction of fracture risk. A few studies report that exercise interventions targeting the trunk muscles can reduce the risk of VFx, improve trunk strength and endurance in patients who have had a VFx, and reduce the risk of falling, a common cause of VFx, but the quality of evidence is low. Trunk muscles likely have an important role to play in prediction, prevention, and management of VFx, but additional longitudinal studies and randomized controlled trials are needed to clarify this role.

Age and gender related neuromuscular pattern during trunk flexion-extension in chronic low back pain patients

BACKGROUND

The root mean square surface electromyographic activity of lumbar extensor muscles during dynamic trunk flexion and extension from standing has repeatedly been recommended to objectively assess muscle function in chronic low back pain patients. However, literature addressing older patients is sparse. This cross sectional study sought to examine differences in neuromuscular activation between age groups (>60 versus 40-60 versus <40 years) and sexes during a standardized trunk flexion-extension task.

METHODS

A total of 216 patients (62 older, 84 middle-aged, 70 younger) performed maximum trunk extensions followed by trunk flexion extension testing thereby holding static positions at standing, half, and full trunk flexion. The lumbar extensor muscle activity and 3d-accelerometric signals intended to monitor hip and trunk position angles were recorded from the L5 (multifidus) and T4 (semispinalis thoracis) levels. Permutation ANOVA with bootstrapped confidence intervals were performed to examine for age and gender related differences. Ridge-regressions investigated the impact of physical-functional and psychological variables to the half flexion relaxation ratio (i.e. muscle activity at the half divided by that in maximum flexion position).

RESULTS

Maximum back extension torque was slightly but significantly higher in youngest compared to oldest patients if male and females were pooled. Normalized RMS-SEMG revealed highest lumbar extensor muscle activity at standing in the oldest and the female groups. Patients over 60 years showed lowest activity changes from standing to half (increments) and from half to the maximum flexion position (decrements) leading to a significantly lower half flexion relaxation ratio compared to the youngest patients. These oldest patients demonstrated the highest hip and lowest lumbothoracic changes of position angles. Females had higher regional hip and gross trunk ranges of movement compared to males. Lumbothoracic flexion and the muscle activity at standing had a significant impact on the half flexion relaxation ratio.

CONCLUSIONS

The neuromuscular activation pattern and the kinematics in this trunk flexion-extension task involving static half flexion position changed according to age and sex. The test has a good potential to discriminate between impaired and unimpaired neuromuscular regulation of back extensors in cLBP patients, thereby allowing the design of more individualized exercise programs.

Effect of short-term application of kinesio tape on the flexion-relaxation phenomenon, trunk postural control and trunk repositioning in healthy females

This study was designed to investigate the potential effects of kinesio tape on the flexion-relaxation phenomenon, trunk postural control and trunk position sense when applied for a short period (30 min) to the low back of healthy female participants. Twenty-four participants were assigned to one of two groups: kinesio tape applied in either the recommended stretched or non-stretched (control) manner over the low back. Tests were performed at three time points (pre-tape, with tape, post-tape) to assess low-back muscle flexion-relaxation, position sense during active trunk repositioning and trunk postural control during seated balance. Results demonstrated that wearing kinesio tape did not affect the angle at which the erector spinae muscles became silent during trunk flexion (flexion-relaxation). Trunk repositioning error increased when wearing kinesio tape in both the stretched and non-stretched manner, and this increased error persisted after the tape was removed. Seated balance control improved when wearing kinesio tape in both the stretched and non-stretched manner, and these improvements persisted after the tape was removed. In conclusion, these findings do not support the general suggestions that short-term use of kinesio tape on the low-back region alter low-back muscle activation and enhance tasks related to proprioception, at least under these taping conditions in a group of healthy females.