Back Extensor Research Articles

Reliability and Validity of the Trunk Control Measurement Scale in Children With Duchenne Muscular Dystrophy

While trunk control is essential for daily activities and motor function, there is currently sparse information regarding the psychometric properties of the outcome measures used for assessing trunk control in Duchenne muscular dystrophy (DMD), characterized by proximal muscle weakness. The Trunk Control Measurement Scale (TCMS) was developed to assess trunk control in children with cerebral palsy. We aimed to examine the reliability and validity of the Turkish version of the TCMS for children with DMD. We determined the functional level of 52 children with DMD (median age: 8.83 years) with the Vignos Scale, and we further evaluated them with the Motor Function Measure (MFM), a gold standard for determining the validity of the TCMS. Internal consistency of the Turkish TCMS was excellent with a Cronbach’s alpha of .95. Intraclass correlation coefficient (ICC) values for intra-rater reliability were between 0.90–0.96 and for inter-rater reliability were between 0.91–0.95. We reported positive moderate to strong correlations between the TCMS and trunk flexors strength ( p < .001, r = 0.77), back extensors strength ( p < .001, r = 0.68) and MFM ( p < .001, r = 0.85). Thus, we found the Turkish version of TCMS to be a reliable and valid instrument for assessing trunk control of children with DMD in clinical and research settings.

Musculoskeletal models determine the effect of a soft active exosuit on muscle activations and forces during lifting and lowering tasks

Exosuits have the potential to mitigate musculoskeletal stress and prevent back injuries during industrial tasks. This study aimed to 1) validate the implementation of a soft active exosuit into a musculoskeletal model of the spine by comparing model predicted muscle activations versus corresponding surface EMG measurements, and 2) evaluate the effect of the exosuit on peak back and hip muscle forces. Fourteen healthy participants performed squat and stoop lift and lower tasks with boxes of 6 and 10 kg, with and without wearing a 2.7 kg soft active exosuit. Participant-specific musculoskeletal models, which included the exosuit, were created in OpenSim. Model validation focused on the back and hip extensors, where temporal agreement between EMG and model estimated muscle activity was generally strong to excellent (average cross-correlation coefficients ranging from 0.84 to 0.98). Root mean square errors of muscle activity (0.05–0.10) were similar with and without the exosuit, and compared well to prior model validation studies without the exosuit (average root mean square errors ranging from 0.05 to 0.19). In terms of performance, the exosuit reduced the estimated peak erector spinae forces during lifting and lowering phases across all lifting tasks but reduced peak hip extensor muscles forces only in a squat lift task of 10 kg. These reductions in total peak muscle forces were approximately 1.7–4.2 times greater than the corresponding exosuit assistance force, which were 146 ± 19 N and 102 ± 14 N at the times of peak erector spinae forces in lifting and lowering, respectively. Overall, the results support the hypothesis that exosuits reduce soft tissue loading, and thereby potentially reduce fatigue and injury risk during manual materials handling tasks. Incorporating exosuits into musculoskeletal models is a valid approach to understand the impact of exosuit assistance on muscle activity and forces.

Effects of track-based stair climbing robot on muscle activity, usability, and psychological anxiety: a preliminary study

This study investigated the effects of using the LiftCar-150 track-based stair-climbing robot on muscle activity, usability, and psychological anxiety. While stair-climbing robots enhance mobility for individuals with physical disabilities, existing research has predominantly focused on engineering perspectives, with limited attention to user-centered outcomes. Ten healthy participants and an 80 kg dummy rider completed stair-climbing tasks at slow (5 m/min) and fast (7 m/min) speeds. Muscle activity in the middle trapezius (MT), erector spinae (ES), multifidus (MF), gluteus maximus (Gmax), gluteus medius (Gmed), and anterior deltoid (AD) muscles was recorded by electromyography. Usability was evaluated in terms of safety, efficiency, and satisfaction using a 5-point Likert scale, while psychological anxiety was assessed with a visual analog scale (VAS) ranging from 0 to 10. Results showed that during stair ascent, activities of the back extensors (ES and MF) and gluteus muscles (Gmax and Gmed) significantly increased compared to descent, while anterior deltoid activity was higher during descent. Usability scores averaged 4.05 for stability, 4.1 for efficiency, and 3.7 for satisfaction. Perceived psychological anxiety scores were 4.2 ± 0.3 and 5.4 ± 0.5 at slow speed, and 3.5 ± 0.2 and 5.7 ± 0.4 at fast speed during ascent and descent, respectively. While operators recognized the robot’s stability and efficiency, satisfaction levels were neutral, and specific muscle activation was increased. These findings provide essential insights into optimizing the design and usability of stair-climbing robots to better address user needs.

Effects of unstable load and unstable surface ontrunk muscles activation and postural control in healthy subjects

Exercise with an unstable load is considered a new training method to activate the core muscles. Research has shown consistency regarding an unstable surface but has not provided comprehensive findings about the effect of an unstable load. The study aimed to examine the impact of an unstable load and unstable surfaces on core muscle activation and postural control during lifting. Thirty-eight participants lifted a load equivalent to 10 % of their body weight under three conditions: a stable load on an unstable surface, a stable load on a stable surface, and an unstable load on a stable surface. The center of pressure (COP) displacement and electromyography activity of abdominal and back extensor muscles were measured during lifting. The results indicated that lifting on an unstable surface activated the lumbar erector spinae and multifidus muscles more than in a stable condition (P<0.05). However, there was no significant difference in the level of thoracic erector spinae muscle activity between the unstable load and unstable surface conditions. The stable condition increased activity in the internal oblique muscle (1.37 times) compared to the unstable conditions. The analysis of postural control revealed that lifting the load on an unstable surface significantly decreased COP displacement in the anteroposterior direction (P<0.05), while holding the load on the unstable surface significantly increased COP displacement in the anteroposterior direction compared to the other conditions. These findings could be valuable for future rehabilitation research, learning appropriate lifting techniques, and setting specific training goals in sports.

Bilateral Back Extensor Exosuit for multidimensional assistance and prevention of spinal injuries.

Lumbar spine injuries resulting from heavy or repetitive lifting remain a prevalent concern in workplaces. Back-support devices have been developed to mitigate these injuries by aiding workers during lifting tasks. However, existing devices often fall short in providing multidimensional force assistance for asymmetric lifting, an essential feature for practical workplace use. In addition, validation of device safety across the entire human spine has been lacking. This paper introduces the Bilateral Back Extensor Exosuit (BBEX), a robotic back-support device designed to address both functionality and safety concerns. The design of the BBEX draws inspiration from the anatomical characteristics of the human spine and back extensor muscles. Using a multi-degree-of-freedom architecture and serially connected linear actuators, the device's components are strategically arranged to closely mimic the biomechanics of the human spine and back extensor muscles. To establish the efficacy and safety of the BBEX, a series of experiments with human participants was conducted. Eleven healthy male participants engaged in symmetric and asymmetric lifting tasks while wearing the BBEX. The results confirm the ability of the BBEX to provide effective multidimensional force assistance. Moreover, comprehensive safety validation was achieved through analyses of muscle fatigue in the upper and the lower erector spinae muscles, as well as mechanical loading on spinal joints during both lifting scenarios. By seamlessly integrating functionality inspired by human biomechanics with a focus on safety, this study offers a promising solution to address the persistent challenge of preventing lumbar spine injuries in demanding work environments.

Comparison of resistance training vs static stretching on flexibility and maximal strength in healthy physically active adults, a randomized controlled trial

BackgroundThe aim of the present study was to compare the effects of resistance training through full range of motion and static stretching (SS) of the hip and lower back extensors on flexibility and strength in healthy, physically active, adults.MethodsEighteen participants (age: 24.2 ± 3.0 years, body mass: 71.3 ± 8.9 kg, height: 172.8 ± 7.5 cm) were randomly assigned to either a Resistance Training (RT) (n = 6), SS (n = 6), or control (CON) group (n = 6). The sit & reach (S&R) flexibility test and maximum isometric straight legged deadlift (ISLDL) at 95% and 50% range of motion (ROM) were tested pre- and post-intervention with significance set at p < 0.05. Both groups conducted four to eight sets per session. Within each set, the RT group performed eight repetitions each lasting four seconds, while the SS group stretched continuously for 32 s. The rest periods between each set were 60–90 s. Consequently training volume and rest times were matched between the groups.ResultsThe RT and SS groups achieved significant, large magnitude improvements in the S&R test compared to the CON group (p < 0.01 g = 2.53 and p = 0.01, g = 2.44), but no differences were observed between the RT and SS groups (p = 1.00). Furthermore, the RT group demonstrated a larger improvement in 50% and 95% ROM ISLDL compared to SS (p < 0.01, g = 2.69–3.36) and CON (p < 0.01, g = 2.44–2.57).ConclusionResistance training through a full ROM was equally effective as SS for improving S&R flexibility, but improved hip- and lower back extensor strength more than SS and the CON. The authors recommend using large ROM resistance training to improve hip and lower back extensor flexibility and muscle strength.Trial registrationISRCTN88839251, registered 24. April 2024, Retrospectively registered.

Effects of Gluteal Muscles Isometrics on Abdominals, Back Extensors and Quadriceps Strength

Background: Weakness of the gluteus muscle is associated with multiple types of injuries such as low back, hip and knee pathology. However, there is no research regarding the effect of gluteal isometric exercises on abdominals, back extensors and quadriceps muscles strength. Hence, this study aimed to demonstrate the effect of gluteal isometric exercises on abdominals, back extensors and quadriceps strength. Methods: A total of 100 healthy students aged between 18 and 25 years were recruited to participate in an 8-week program of gluteal muscle isometric exercises. The strength of the abdominal, back extensor, and quadriceps muscles was assessed both at baseline and after the 8-week intervention period. Results: A paired sample t-test revealed significant improvements in abdominal muscles, back extensor muscle strength (p&lt;0.001), and quadriceps muscle strength (p=0.037) after an 8-week intervention. The greatest increases were observed in the abdominals (59.05%), back extensors (46.78%), and quadriceps (7.13%). Conclusion: This study demonstrates that gluteal isometric exercises had a significant positive effect on the strength of abdominals, back extensors and quadriceps muscles.

Age-related changes in reticulospinal contributions to anticipatory postural adjustments between back extensors and abdominal muscles.

Anticipatory postural adjustments (APAs) give feedforward postural control of the trunk, but they are delayed with ageing, affecting balance and mobility in older individuals. The reticulospinal tract contributes to postural control of the trunk; however, the extent to which age-related changes affect the reticulospinal contributions to APAs of the trunk remains unknown in humans. Here, we tested the hypothesis that a startling acoustic sound, which activates the reticulospinal tract, improves delayed APAs in older individuals. Twenty-two old (75±6years) and 20 healthy young adults (21±4years) performed a self-initiated fast bilateral shoulder flexion or shoulder extension task in response to visual, visual and auditory (80dB), or visual and startling (115dB) cues. Electromyography (EMG) was recorded from bilateral anterior deltoid (AD) and erector spinae (ES) during shoulder flexion and from bilateral posterior deltoid (PD) and rectus abdominis (RA) during shoulder extension. EMG onset of all muscles shortened during the startling cue in both age groups, suggesting a non-specific modulation of the reticulospinal tract on prime movers (AD or PD) and non-prime movers (ES or RA). Interestingly, APAs of the ES were accelerated in older participants to a similar degree as in younger participants during the startling cue. Conversely, APAs of the RA were not influenced by the startling cue in older participants. Our results suggest differential effects of ageing on functional contributions of the reticulospinal tract to APAs between back extensors and abdominal muscles.

Biomechanical analysis of different back-supporting exoskeletons regarding musculoskeletal loading during lifting and holding

Industrial back support exoskeletons (BSEs) are a promising approach to addressing low back pain (LBP) which still affect a significant proportion of the workforce. They aim to reduce lumbar loading, the main biomechanical risk factor for LBP, by providing external support to the lumbar spine. The aim of this study was to determine the supporting effect of one active (A1) and two passive (P1 and P2) BSEs during different manual material handling tasks. Kinematic data and back muscle activity were collected from 12 subjects during dynamic lifting and static holding of 10 kg. Mean and peak L5/S1 extension moments, L5/S1 compression forces and muscle activation were included in the analysis. During dynamic lifting all BSEs reduced peak (12–26 %) and mean (4–17 %) extension moments and peak (10–22 %) and mean (4–15 %) compression forces in the lumbar spine. The peak (13–28 %) and mean (4–32 %) activity of the back extensor muscles was reduced accordingly. In the static holding task, analogous mean reductions for P1 and P2 of L5/S1 extension moments (12–20 %), compression forces (13–23 %) and muscular activity (16–23 %) were found. A1 showed a greater reduction during static holding for extension moments (46 %), compression forces (41 %) and muscular activity (54 %). This pronounced difference in the performance of the BSEs between tasks was attributed to the actuators used by the different BSEs.

The effects of back extensor strength in different body positions on health-related quality of life in patients with degenerative spinal deformity.

Degenerative spinal deformity (DSD) is believed to originate from degeneration of the discs and facet joints and vertebral wedging. Currently, the nosogeny of DSD is not yet fully clarified and there has been no systematic study on the impact of their lower back muscle strength on quality of life. To determine the characteristics of back extensor strength (BES) in different body positions and examine their correlations with health-related quality of life (HQOL) in degenerative spinal deformity (DSD) patients. Participants comprised 60 DSD patients and 40 healthy volunteers. Maximal isometric BES was evaluated by dynamometers with the subject in three different positions (standing, prone, sitting). The visual analogue scale (VAS) score, Oswestry Disability Index (ODI), Roland-Morris Disability Questionnaire (RMQ), and 36-item Short Form Health Survey (SF-36) score were used to evaluate patient HQOL. Correlations between the BES in different body positions and HQOL wereanalysed. The BES values in three body positions were significantly smaller in DSD patients than healthy subjects (P< 0.05). The standing BES was found to be negatively associated with ODI and RMQ (R= 0.313, p< 0.05 and R= 0.422, p< 0.01, respectively). A negative relationship between sitting BES and RMQ was also seen (R= 0.271, p< 0.05). In addition, the standing and prone BES were positively correlated with the physical functioning score of the SF-36 (R= 0.471, p< 0.01 and R= 0.289, p< 0.05, respectively), and the sitting BES was positively correlated with the role-physical score of the SF-36 (R= 0.436, p< 0.01). The results indicate that the back extensor muscle is compromised in DSD patients and there are differences in predicting the severity of disability and physical HQOL scores with BES in different positions. Standing BES was the most reliable contributor to HQOL among three body positions.

INSIGHTS INTO HUMAN LOCOMOTION STRATEGIES AND MOTOR LEARNING FOR AN AGEING POPULATION USING TRANSFER TESTING AND COUPLED SIMULATIONS

The elucidation of human locomotion strategies has potential applications in the prevention of sarcopenia and in the reduction of falls. Given the diverse biochemical, mechanical and functional age-related changes seen in the neuro-musculoskeletal system, the decline in motor function is difficult to study experimentally. In this study, we use transfer testing and coupled simulation strategies within a deep reinforcement learning environment to better understand the complex problem of motor control adaptation to age-related changes. Using transfer testing, a 3D musculoskeletal model is separately trained on parameters of the young adult model (Y) for either forward or backward falls after completing two steps forward, and tested using a 30% age-related reduction for all parameters (M_all). This strategy produces a backward fall for a forwardly trained simulation, showing potential sensitivity of these parameters to a given fall direction. Second, a coupled simulation solution is used to simulate recovery from falls by considering the center-of-mass position relative to the base of support. Results for the M_all trained model showed a longer simulation time and a greater vertical pelvis velocity with a maximal value of 4.26[Formula: see text]m/s. In particular, the results of the coupled simulations clearly show that both the young and M_all condition models respond with a step back and stronger leg extensor activations to propel the model forward to recover from the simulated fall. We developed a novel coupling between transfer testing and coupled simulation strategies to improve upon muscle models for characterizing muscle function, and also to begin testing different hypotheses, such as the strategy and force required to avoid a fall at different limits. This opens new avenues for precision rehabilitation with patient-specific muscle-driven recovery exercises.

Determining whether biomechanical variables that describe common ‘safe lifting’ cues are associated with low back loads

Lift technique training programs have been implemented to help reduce injury risk, but the underlying content validity of cues used within these programs is not clear. The objective of this study was to determine whether biomechanical variables, that commonly used lifting cues aim to elicit, are associated with resultant low back extensor moment exposures. A sample of 72 participants were recruited to perform 10 repetitions of a floor-to-waist height barbell lift while whole-body kinematics and ground reaction forces were collected. Kinematic, kinetic, and energetic variables representative of characteristics commonly targeted by lifting cues were calculated as predictor variables, while peak and cumulative low back moments were calculated as dependent measures. Multiple regression revealed that 56.6–59.2% of variance in low back moments was explained by predictor variables. From these regression models, generating motion with the legs (both greater hip and knee work), minimizing the horizontal distance of the body to the load, maintaining a stable body position, and minimizing lift time were associated with lower magnitudes of low back moments. These data support that using cues targeting these identified variables may be more effective at reducing peak low back moment exposures via lift training.

Effect of aerobic exercises on patients with chronic mechanical low back pain: A randomized controlled clinical trial

BackgroundChronic mechanical low back pain (CMLBP) is one of the most prevalent and costly disorders. Determining its most effective treatment approach is a priority for researchers. PurposeTo examine the effects of including aerobic exercise within a conventional therapy regimen for young adults with CMLBP. MethodsFifty CMLBP patients (22 males and 28 females) were randomly and equally assigned to one of two groups to receive the prescribed treatment for 8 weeks. The control group received the traditional program only (infrared, ultrasound, burst TENS, and exercises); for the experimental group, an aerobic training program using a stationary bicycle was added. Back pain intensity was the primary outcome. Secondary outcomes included the Oswestry disability index, back extensor endurance measured by the Sorensen test, and physical performance indicated by the back performance scale and the 6-min walk test. A Two-way MANOVA was used for data analysis. ResultsMultivariate tests revealed statistically significant effects of group (p = 0.002, partial η2 = 0.182), time (p < 0.001, partial η2 = 0.928), and group-by-time interaction (p = 0.01, partial η2 = 0.149). Univariate group-by-time interactions were significant for back disability (p = 0.043), extensor endurance (p = 0.023) and results of the 6-min walk test (p = 0.023) showing greater improvement in the experimental group. However, back pain intensity and the back performance scale revealed no significant group-by-time interactions. Within-group comparisons were significant for all measured variables in both groups (p < 0.001). ConclusionAlthough a traditional program of infrared, ultrasound, TENS, and exercises is beneficial for CMLBP treatment, adding aerobic exercises to the program leads to more beneficial outcomes.

Physical relief potential through robot-assisted mobilization in nursing care: an exploratory study

PurposePhysically demanding activities at the nursing bed are a key factor in the overwork of nursing staff and play a major role in the development of musculoskeletal disorders. The heavy back strain plays a significant part in this. Technical aids such as robotic assistance systems have the potential to minimize this overload during nursing activities. In the present work, we have investigated the relief potential of a supporting robotic assistance system developed in the AdaMeKoR project. An exploratory study design was developed to assess the relief potential of the robotic system for nurses during the care action of repositioning from the supine position to the sitting position at the edge of a nursing bed under kinaesthetic principles.MethodsThe study was conducted in March 2022 with a total of 21 nursing professionals participating. Safety precautions at this stage of the robot’s development made it necessary to use a 40 kg patient simulator instead of having a human act as the patient. Each participant performed the repositioning three times in the conventional manner and three times with the robotic-assistance. The conventional and the robotic-assisted task execution was compared using different perspectives of analysis. From a sensory perspective, ground reaction forces and electromyography data were collected and analyzed. A kinaesthetic perspective was added using 3D-video data which was analyzed by professional kinaesthetics trainers. A third perspective was added by collecting the subjective workload experiences of the participants.ResultsWhile participants’ self-assessment based on a NASA-TLX questionnaire suggests more of a physical and psychological strain from using the robot, electromyography shows a 24.41% reduction in muscle activity for left back extensors and 7.99% for right back extensors. The kinaesthetic visual inspection of the study participants also allows conclusions to be made that the robot assistance system has a relieving effect when performing the nursing task.ConclusionsThe conducted study suggests that overall the robotic-assistance has the potential of relieving nurses of partial physical exertion during mobilization. However, the different focuses of analysis show varying results in regard to external, i.e. sensor data and expert analysis, compared to internal, i.e. the nurses, perspectives. Going forward, these results have to be further expanded to get more robust analyses and insights on the interdependencies of subjective factors contributing to the experience of workload. In view of the fact that robotics for nursing is still a relatively new field and there are various lessons to be learned regarding the conceptualization of studies and corresponding evaluations, our approach of combining perspectives of analysis allows for a more differentiated view of the subject at hand.

Trunk muscle dysfunction in patients with myotonic dystrophy type 2 and its contribution to chronic low back pain.

Myotonic dystrophy type 2 (MD2) presents with a varied manifestation. Even though the myopathy in these patients is more widespread, axial musculature involvement is one of the most prominent conditions. MD2 patients also often report chronic low back pain (CLBP). The purpose of this study was to evaluate trunk muscle function, including respiratory muscles, in patients with MD2 and to compare it with healthy controls, to determine the occurrence of CLBP in patients with MD2, and to assess whether trunk muscle dysfunction increases the risk of CLBP in these patients. We enrolled 40 MD2 patients (age range 23 to 76 years, 26 women). A comprehensive battery of tests was used to evaluate trunk muscle function. The tests consisted of quantitative muscle strength testing of low back extensor muscles and respiratory muscles and the assessment of trunk muscle endurance. A neurological evaluation contained procedures assessing the distribution of muscle weakness, myotonia, and pain, and used questionnaires focused on these items and on disability, depression, and physical activity. The results of this study suggest that patients with MD2 show significant dysfunction of the trunk muscles, including the respiratory muscles, expressed by decreased muscle strength and endurance. The prevalence of CLBP in patients with MD2 was 52.5%. Based on our analysis, the only independent significant risk factor for CLBP in these patients was maximal isometric lower back extensor strength in a prone position ≤ 15.8 kg (OR = 37.3). Other possible risk factors were severity of myotonia and reduced physical activity. Outcomes of this study highlighted the presence of axial muscle dysfunction, respiratory muscle weakness, and frequent occurrence of CLBP together with its risk factors in patients with MD2. We believe that the findings of this study may help in management and prevention programs for patients with MD2.

Effect of Individualized Mat Pilates Exercises on Speed, Agility and Back Extensor Endurance in a Deconditioned Athelte – A Case Study

Effect of Individualized Mat Pilates Exercises on Speed, Agility and Back Extensor Endurance in a Deconditioned Athelte – A Case Study

Rural-urban differences of sarcopenia and spinal health in the older women: a comparative observational study.

We aimed to investigate the correlation between spinal sarcopenia, spinal sagittal balance (SSB), and spinal function in older women living in rural areas versus those of the older urban women in our previous study. Twenty-five older rural-dwelling women aged more than 70 years were compared with 24 older urban-dwelling women from our previous study. Demographic variables, conventional and spinal sarcopenic indices, variable functional outcome parameters, occupational state, and exercise participation rate were evaluated. We also measured the isometric back extensor strength, radiological parameters for SSB on whole-spine radiography, and volumetric parameters of the lumbar extensor muscle on computed tomography. There were no significant intergroup differences in demographic variables or the prevalence of sarcopenia. Older women in rural areas had greater handgrip strength than those in urban areas (22.7&plusmn;3.7 kg v 20.0&plusmn;3.4 kg, p=0.010). However, their mean lumbar lordosis angle was lower (31.7&plusmn;15.3&deg; v 42.3&plusmn;11.2&deg;, p=0.012). Isometric back extensor strength was lower in rural women than in urban women. The vocational activity participation rate of rural women was significantly higher (84% v 12.5%, p<0.001), whereas their exercise participation rate was significantly lower (60% v 92%, p<0.001). Older women in rural areas had greater handgrip strength and vocational participation rates but lower back extensor strength and exercise participation rates. Therefore, more attention is needed for healthcare services to support their spinal health and exercise habits.

Back Extensor Strength as a Potential Marker of Frailty Using Propensity Score Matching and Machine Learning.

This study assessed the potential of back extensor strength as an alternative marker of frailty. A total of 560 farmers were included. Computed tomography scans measured fat and muscle mass volumes at the mid-L4 vertebral level. Back extensor strength was measured in a seated posture. Multivariate linear regression was used to analyze the associations between back extensor strength and trunk muscle/fat compositions. The participants were divided into two groups based on back extensor strength. Propensity score matching, multivariate logistic regression, and Extreme Gradient Boosting (XGBoost) were employed to evaluate the relationship between Fried's frailty criteria and back extensor strength. Back extensor strength exhibited positive associations with abdominal muscle volume (r = 1.12) as well as back muscle volume (r = 0.89) (p < 0.05). Back extensor strength was linked to more frail status, such as reduced grip strength, walking speed, and frequent self-reported exhaustion. Multivariate logistic regression indicated that back extensor strength was associated with higher frail status (OR = 0.990), and XGBoost analysis identified back extensor strength as the most important predictor (gain = 0.502) for frailty. The prediction models using grip strength produced similar results (OR = 0.869, gain = 0.482). These findings suggested the potential of back extensor strength as an alternative frailty marker.

Which trunk muscle parameter is the best predictor for physical function in older adults?

BackgroundDespite preliminary evidence demonstrating the relevance of trunk muscle strength for physical function in older adults, it is not clear which muscle-related trunk parameter is the best predictor for physical functions. Therefore, this study aimed to compare trunk muscle morphology or strength parameters regarding their predictive ability for physical functions. MethodsSeventy-four older adults (38 men, 36 women, mean age 76.85 years) were tested for maximum absolute and relative isokinetic trunk flexion and extension strength, trunk lean mass, and trunk muscle quality. Functional assessment included normal and fast walking speed, repeated sit-to-stand transfer, timed up and go, and postural sway during a closed-feet and a semi-tandem stance adjusted for body height. Pearson's correlations were used to compare relationship between trunk strength adjusted and unadjusted for body weight to physical functions. Linear regression analysis including sex and age as co-variables was performed between trunk muscle and functional test parameters. ResultsRelative back extension strength was the most consistent significant predictor for all physical function tests (p = 0.004–0.04) except for postural sway. Relative trunk flexion strength was related to normal walking speed (p = 0.024). Trunk lean mass was related to timed up and go performance (p = 0.024). ConclusionRelative back extension strength is associated with better performance in nearly all standard tests for physical function in older adults, while trunk flexion strength and lean mass seem to play a minor role. Our findings emphasize the importance of trunk muscle strength, especially the back extensor muscles, for physical function in older adults.

The effect of additional transcutaneous auricular vagus nerve stimulation on back muscle endurance of chronic low back pain

Background: This study aims to investigate the effects of adding transcutaneous auricular vagus nerve stimulation (tVNS) to exercise therapy on back extensor muscle endurance of patients with mechanical chronic low back pain (CLBP). Methods: A randomized controlled group study was conducted on 22 patients with mechanical CLBP aged 16-55. Participants were randomized into an exercise group (control) and an exercise with a tVNS group (experimental). The outcome was back extensor muscle endurance measured by the Biering Sorensen Test (BST), evaluated before and after 2 weeks of intervention Results: There was a significant improvement in pre-post evaluation in the intervention group (before: 40.30± 31.20 and after: 66.49±45.87, p&lt;0.05), with a large effect size (Cohen’s d=0.918). No difference in pre-post evaluation in the control group (before: 58.18±50.75; after: 66.82±38.56; p&gt;0.05) with a small effect size (Cohen’s d=0.414). There was no significant difference between the delta BST of the two groups (p=0.418). Conclusion: Our results suggest that no difference was found between the two groups. However, tVNS addition to exercise therapy showed beneficial effects potency on back muscle endurance of the experimental group in CLBP patients during a relatively short period in two weeks of intervention. Further research is needed to confirm the potential of tVNS therapy in CLBP.