Back Extensor Research Articles

Novel lateral whole-body dual-energy X-ray absorptiometry of lumbar paraspinal muscle mass: results from the SarcoSpine study.

BackgroundHere, we aimed to propose novel lateral whole‐body dual‐energy X‐ray absorptiometry (lateral DXA) as a simple tool for measuring spinal muscle mass and investigate the feasibility of lateral DXA to measure lumbar paraspinal muscle (LPM) mass compared with lumbosacral spine three‐dimensional magnetic resonance imaging (3D MRI).MethodsTwenty consecutive participants were enrolled from a prospective observational cohort (SarcoSpine study). Lateral DXA was scanned with each participant in the lateral decubitus position. The region of interest was defined to analyse the LPM mass. LPM total volume, LPM cross‐sectional area at the L3 mid‐vertebra and L4/5 mid‐disc levels and each signal intensity were measured by 3D MRI. Isokinetic and isometric back extensor muscle strengths as well as back extensor endurance were examined. The correlation between lateral DXA‐based mass (weight) and 3D MRI‐based LPM volume was analysed.ResultsThe mean age of the 20 participants (15 women, 5 men) was 72.2 ± 4.9 years. LPM mass by lateral DXA was positively correlated with LPM volume by 3D MRI (β = 0.333, r = 0.692, p < 0.001) and negatively correlated with signal intensity of the total LPM (β = −0.263, r = −0.530, p = 0.016). LPM mass was also correlated with appendicular limb muscle mass, handgrip strength and gait speed as well as back extensor endurance (r = 0.620, p = 0.004).ConclusionsOur data suggest that LPM mass assessed by lateral DXA was positively correlated with LPM volume by 3D MRI in older adults. Lateral DXA may be a potential substitute for the cross‐sectional area measurement of LPM mass. Further studies are required to validate this lateral DXA technique.

Effectiveness of an exercise-based prehabilitation program for patients awaiting surgery for lumbar spinal stenosis: a randomized clinical trial

Lumbar spinal stenosis is the most common reason for spine surgery in older adults, but the effects of prehabilitation on perioperative outcomes among these patients have not been investigated. This study aims to evaluate the effectiveness of a preoperative exercise-based intervention program compared with usual care on the improvement of clinical status, physical capacities and postoperative recovery of patients awaiting surgery for lumbar spinal stenosis. Sixty-eight participants were randomised to receive either a 6-week supervised exercise-based prehabilitation program or hospital usual care. The outcomes included both clinical and physical measures. Data collection occurred at post-intervention, and 6 weeks, 3- and 6-months post-surgery. Significant but small improvements were found in favour of the experimental group at the post-intervention assessment for pain intensity, lumbar spinal stenosis-related disability, lumbar strength in flexion, low back extensor muscles endurance, total ambulation time, and sit to stand performance. A significant difference in favor of the intervention group was found starting at the 3-month postoperative follow-up for low back-related disability. No adverse events were reported. Exercise-based prehabilitation did not improve short-term postoperative recovery in patients with lumbar spinal stenosis.

Rehabilitation therapy for patients with osteoporosis

Fractures in patients with osteoporosis are attributable to falls and reduced bone mass. Therefore, balance and muscle strength should be improved and bone mass should be increased to prevent fractures. This study aims to investigate a rehabilitation treatment for osteoporosis. Exercise is a potentially safe and effective way to increase bone density and prevent postmenopausal bone loss. Based on bone densitometry results, rehabilitation exercises can be applied variably. Fractures caused by osteoporotic fragility may be prevented with multidisciplinary intervention programs including education, environmental modifications, aids, and individually tailored exercise programs. In addition, strengthening the paraspinal muscles may not only maintain bone mineral density but also reduce the risk of vertebral fractures. Rehabilitation after vertebral fractures includes proprioceptive dynamic posture training that decreases kyphotic posturing through the recruitment of back extensors. This training reduces pain, improves mobility, and leads to a better quality of life. Hip fractures may be prevented by hip protectors and exercise programs that can improve the strength and mobility of patients with hip fractures. Considering the musculoskeletal condition, the spine should be protected using a spinal orthosis, taping, hip pad, and walking aid, if necessary. Efforts to activate programs such as fracture liaison services should also be considered.

Effects of back extensor and hip abductor fatigue on dynamic postural stability in patients with nonspecific chronic low back pain: A case-control study

ABSTRACT Introduction Patients with nonspecific chronic low back pain (NSCLBP) complain of pain and fatigue during functional activities. Poor back muscle endurance has been associated with recurrent pain and long-term disability. However, the relationship between proximal muscle fatigue and postural stability is not well understood. Purpose To investigate the effects of lumbar extensor and hip abductor fatigue on postural stability in NSCLBPs. Methods To induce isolated fatigue, participants (24 LBPs, 24 controls) were asked to perform multiple back extension and hip abduction in the separate sessions until the muscle force reached 60% of pre-fatigued force. The overall (OSI), anteroposterior (APSI), and mediolateral (MLSI) stability indices were measured during single-leg stance using the Biodex dynamic platform. Results The results revealed higher postural instability (APSI and OSI) following fatiguing lumbar extensor and hip abductor muscles (greater effect size for APSI than OSI) in LBPs than controls. Furthermore, significant and inverse relationships were found between the level of physical activity, pain, and post-fatigue postural instability (OSI) in NSCLBPs. Conclusion Fatigue of proximal muscles could differentiate postural stability primarily in the sagittal plane between NSCLBPs and controls. Therefore, reducing the fatigability of these muscles by endurance training in addition to balance training may improve physical activity.

Comparison of two manual therapy approaches combined with exercise on pain, strength and electromyographic muscle activity in athletes with subacute mechanical low back pain

Subacute mechanical low back pain (MLBP) has been found to increase significantly in athletes in the past decade. Manual therapy combined with exercises seems to be promising option; however, its potential effect in athletes is not fully known yet. The study aimed to compare between the effects of mulligan sustained natural apophyseal glides (SNAG) combined with exercise, muscle energy technique (MET) combined with exercise therapy and exercise therapy alone on pain, strength and muscle activity in athletes with subacute mechanical low back pain (MLBP). The athletes were screened for inclusion into the study using physical examination and Oswestry Disability Index (ODI). The study was a randomized 3 arm repeated measure design and a total of thirty athletes completed the study (n = 30). Athletes in group 1 received mulligan sustained natural apophyseal glides (SNAG) combined with exercise, group 2 received muscle energy technique (MET) combined with exercise while those in group 3 were submitted to exercise only. Athletes in all groups received treatment 3 times a week for 4 weeks. The outcome measures were visual analog scale (VAS) scores, back extensor strength and electromyographic (s EMG) muscle activity of longissimus lumborum (LL) and transversus abdominis (Tr A). The VAS score were decreased in all three groups (p < 0.05); however, group 2 and group 1 were more effective than group 3 (p < 0.05). The back extensor strength increased in two groups (p < 0.05): group 2 showed a significant increase compared to group 1. The s EMG muscle activity of LL and Tr A increased in two groups (p < 0.05): group 2 showed a significant increase compared to group 1. There were significant time, group and interaction effects for the three outcome measures (p < 0.05). The addition of MET combined with exercise therapy reduces pain level, improves back extensor strength and muscle activity of LL and TrA in athletes suffering with subacute MLBP more than mulligan SNAG combined with exercise therapy and exercise therapy alone.

Application of bilateral erector spinae plane block as a component of multimodal analgesia in pediatric practice: a case report

The article describes a clinical case of using a modified blockade of the back extensor muscle space as a component of postoperative multimodal analgesia in a toddler who was urgently operated on for extensive phlegmon of the anterior abdominal wall. This clinical case demonstrated the effectiveness of this method, and its use is quite simple in pediatric practice.

Exploring Associations of Preoperative Physical Performance With Postoperative Outcomes After Lumbar Spinal Fusion: A Machine Learning Approach

ObjectiveTo explore the association between preoperative physical performance with short- and long-term postoperative outcomes in patients undergoing lumbar spinal fusion (LSF). DesignRetrospective cohort. SettingUniversity hospital. ParticipantsSeventy-seven patients (N=77) undergoing elective LSF were preoperatively screened on patient demographics, patient-reported outcome measures, and physical performance measures (movement control, back muscle endurance strength and extensor strength, aerobic capacity, flexibility). InterventionsNot applicable. Main Outcome MeasuresAssociations between preoperative variables and inpatient functional recovery, hospital length of stay (LOS), and 1- to 2-year postoperative pain reduction were explored using random forest analyses assessing the relative influence of the variable on the outcome. ResultsAerobic capacity was associated with fast functional recovery <4 days and prolonged functional recovery >5 days (median z scores=7.1 and 12.0). Flexibility (median z score=4.3) and back muscle endurance strength (median z score=7.8) were associated with fast functional recovery <4 days. Maximum back extensor strength was associated with prolonged functional recovery >5 days (median z score=8.6). Flexibility (median z score=5.1) and back muscle endurance strength (median z score=13.5) were associated with short LOS <5 days. Aerobic capacity (median z score=8.7) was associated with prolonged LOS >7 days. Maximum back extensor strength (median z score=3.8) was associated with 1- to 2-year postoperative pain reduction and aerobic capacity (median z score=2.8) was tentative. ConclusionsPhysical performance measures were associated with both short- and long-term outcomes after LSF. Adding these measures to prediction models predicting outcomes after LSF may increase their accuracy.

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

BackgroundInspite 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 questionHow do differences in lumbar posture influence trunk extensor strength (moment), trunk muscle activity, and neuromuscular efficiency during maximal lifting? MethodsTwenty-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. ResultsSignificantly 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. SignificanceA 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.

Effect of Lower Back Extensors Fatigue on Athletic Performance Measured as Agility

Background: At high level of competition, sports require long periods of hard physical work. Each athlete should be able to perform desired actions efficiently, which will not be possible without coordinated activation of muscles in the kinetic chain. EMG studies demonstrate that lumbar paraspinal muscles fatigue is associated with Quadriceps Inhibition (QI), leading to speculation that these changes may not only have adverse effect for athletic performance but also increase the risk of injury in long term. This contrasts the evidence about the influence of fatigue on trunk muscles reflex activity. Method: 37 athletes (men) were recruited from city soccer clubs. The participants performed sub maximal isometric exercise of lower back extensors (Ito’s test) to induce fatigue. The two protocols were a single bout and repeated bouts of Lumbar Extension Isometric Exercise (LEIE). The Agility scores recorded at baseline, after single bout and after repeated bouts of LEIE were compared. Conclusion: The two experimental interventions differently affected the agility performance in the sample. On one hand, single bout intervention led to improved performance, repeated bout intervention resulted in relative deterioration of performance.

Relationship of back muscle and knee extensors with the compensatory mechanism of sagittal alignment in a community-dwelling elderly population

Compensatory mechanisms, such as a decrease in thoracic spine kyphosis and posterior tilting or rotation of the pelvis, aim to achieve optimal alignment of the spine. However, the effect of muscle strength on these compensatory mechanisms has not been elucidated. This study aimed to investigate the impact of back muscle and lower extremity strength on compensatory mechanisms in elderly people. Overall, 409 community-dwelling elderly participants (164 men, 245 women) were included. Age, disc degeneration, and 2 or more vertebral fractures showed a significant increase of risk for sagittal vertical axis (SVA) deterioration. Conversely, stronger back, hip flexor, and knee extensor muscles reduced the risk for SVA deterioration. To investigate the association of each muscle’s strength with compensatory mechanisms, 162 subjects with pelvic incidence-lumbar lordosis > 10° were selected. The linear regression model for thoracic kyphosis demonstrated a negative correlation with back muscle strength and positive correlation with vertebral fracture. The regression analysis for pelvic tilt demonstrated a positive correlation with knee extensor strength. Back, hip flexor, and knee extensor muscle strength were associated with sagittal spinal alignment. Back muscle strength was important for the decrease in thoracic kyphosis, and knee extensor strength was associated with pelvic tilt.

Comparison of Isometric Endurance of Abdominal and Back Extensor Muscles in Manual and Sedentary Males in the Age Group of 20-40 Years

Background: Stabilization of trunk flexors and extensors are essential for normal lumbo-pelvic function. These muscles, known as “core muscles”, have a basic role in balance and coordination in sitting. The core is the lumbopelvic- hip complex which includes lumbar spine, pelvis, hips, and their respective musculature. Pattern of core activity changes in sitting and dysfunction of core muscles increased the risk of damage of the upper and lower extremities segments. Powerful core muscles support stabilizes the vertebra and pelvis, prevents balance disorder and decreases the rate of LBP which is one of the most prevalent occupational disorders. Endurance of trunk muscles depends on the life style and working condition of individuals. Imbalance in the trunk muscle endurance secondarily leads to back pain, which disables the person and reduces the functional capacity of individuals. Objective: The aim of this study is to evaluate the difference in isometric endurance between abdominal and back extensor muscle in manual and sedentary workers and guide them about the importance of endurance training in preventing the back pain in the future. Materials and methods: This study includes 40 simple randomly sampled normal male subjects according to the inclusion and exclusion criteria in the age group of 20-40 years, recruited on voluntary basis and allotted to Group A (N=20, Manual workers) and Group B (N=20, Sedentary workers). Modified Kraus weber’s test for abdominal muscles and Modified Sorensen’s test for back extensor muscles were performed by both Group A and Group B in two successive trials for each test with a rest break of 3-5 minutes in between the trials and the best of trials in seconds is recorded with a stop watch and the data is analyzed using SPSS statistics software version 19. Results: The isometric abdominal muscles endurance is more in manual workers than the sedentary workers, at a significance level of p<0.005.The isometric endurance of back extensor muscles is more than isometric abdominal muscles in both the groups, at a significance level of p<0.005.The isometric back extensor muscles endurance is more in manual workers than in sedentary workers, at a significance level of p<0.005. Conclusion: The isometric abdominal muscles endurance is less in both the groups as compared to isometric back extensor muscles endurance. So, abdominal muscles should be concentrated during endurance training. The objective of any fitness regime, maintenance of good health and posture and treatment of back pain is identifying dangerous causes that require immediate attention and attempt to prevent chronic low back pain problems. The modified Sorensen’s and Kraus Weber’s test can be used to asses and train the trunk muscles endurance as they are simple, easy, reliable and replace the costly and time consuming machine methods for evaluating and training endurance.

Effects of back extensor strengthening exercises on postural alignment, physical function and performance, self-efficacy, and quality of life in Japanese community-dwelling older adults: A controlled clinical trial.

To examine the changes in postural alignment and kyphosis-correlated factors after 6 months of back extensor strengthening exercise in a group of community-dwelling older adults aged ≥65 years. We quasi-randomized 29 subjects into an intervention group treated with a back extensor strengthening program and a control group treated with a full-body exercise program. These groups completed 20-30 minutes of exercise directed by a physical therapist one or more times per week and were instructed to exercise at home as well. The participants were assessed prior to and after the intervention using the following criteria: postural alignment of "usual" and "best" posture, physical function, physical performance, self-efficacy, and quality of life. The differences between two factors (group and period) were compared for each of the measurement variables. Subjects who adequately completed the exercises were analyzed. A reduced knee flexion angle was noted in the "best" posture of both groups, as were improved physical function and performance with the exception of one-leg standing time. Verifying the effect size in the post-hoc analysis, the body parts that showed changes to postural alignment after the intervention differed between groups. Back extensor strengthening exercises improved physical function and performance, but did not improve spinal alignment. The changes due to these interventions were not significantly different from changes observed in the full-body exercise group. However, post-hoc analysis revealed that the effect size of posture change was different, possible indicating that the two groups experienced different changes in the postural alignment.

Changes in Low Back Muscle Activity and Spine Kinematics in Response to Smartphone Use During Walking.

Within-subject design of an experimental study. The aim of this study was to determine the effects of smartphone use on the activity level of the lumbar erector spinae muscles and spine kinematics during walking. Using a smartphone while walking makes the user hold the phone steady and look downward to interact with the phone. Walking with this non-natural posture of the head and the arms may alter the spine kinematics and increase the muscular load on the low back extensor muscles. Twenty healthy young individuals participated in the laboratory experiment. Each participant walked on a treadmill in five different conditions: normal walking without using a phone, conducting one-handed browsing while walking, two-handed texting while walking, walking with one arm bound, and walking with both arms bound. Spine kinematics variables and the myoelectric activity levels of the lumbar erector spinae muscles were quantified and compared between the five walking conditions. Participants walked with significantly (P < 0.05) more thoracic kyphosis and lumbar lordosis when using a phone compared to when walking without using the phone. The median level of muscle activity was also 16.5% (browsing) to 31.8% (texting) greater for the two smartphone use conditions than for the normal walking condition, and the differences were significant (P < .05). Between the normal walking and the two bound arm walking conditions, no significant difference in the muscle activity was found. Study results show that the concurrent use of a smartphone while walking could pose a larger muscular load to the lumbar erector spinae muscles than that of normal walking. Habitual use of a smartphone while walking could be a risk factor for low back musculoskeletal problems.Level of Evidence: N/A.

The immediate and short-term effects of dynamic taping on pain, endurance, disability, mobility and kinesiophobia in individuals with chronic non-specific low back pain: A randomized controlled trial.

Evidence suggests that the application of Kinesio Tape (KT) on patients with chronic non-specific low back pain (CNLBP) is inconclusive. Dynamic tape (DT) is a relatively new treatment technique, which is increasingly being used as an adjunctive method to treat musculoskeletal problems. To our knowledge, no study has investigated the application of DT in individuals with CNLBP. To compare the immediate and short-term effects of DT versus KT and no tape among patients with CNLBP on pain, endurance, disability, mobility, and kinesiophobia. Forty-five patients with CNLBP were randomly assigned to 1 of 3 groups. Outcomes were measured at baseline, immediately, and on the third day post-application of tapes. The primary outcomes of pain, endurance, and disability were measured through the visual analog scale (VAS), Biering–Sorensen test, and Oswestry disability index (ODI), respectively. Secondary outcome measures of mobility and kinesiophobia were measured using the modified–modified Schober test and the Tampa Scale of Kinesiophobia, respectively. No significant immediate and short-term differences were found between DT and KT in pain, disability, mobility, and kinesiophobia. Improved back extensor endurance was observed for the DT group than KT (p = 0.023) and control group (p = 0.006). The application of DT may result in improvements only in back extensor endurance among individuals with CNLBP. This finding suggests that DT controls the processes that lead to back muscle fatigue.

An Enhanced Planar Linked Segment Model for Predicting Lumbar Spine Loads during Symmetric Lifting Tasks

The present technical note aimed at enriching the planar linked segment model originally proposed by Chaffin with the prediction of the moment arm and of the orientation of the line of action of the back extensor muscles during symmetric lifting tasks. The prediction equations proposed by van Dieen and de Looze for their single equivalent muscle model were used for such a purpose. Their prediction was based on the thorax-to-pelvis flexion angle as computed from 3D video-based motion capture. In order to make these prediction equations compliant with a two-dimensional analysis, the planar angle formed by the segment joining L5/S1 to the shoulder with the longitudinal axis of the pelvis was introduced. This newly computed planar trunk flexion angle was used to feed van Dieen and de Looze’s equations, comparing the results with the original model. A full-body Plug-in-Gait model relative to 10 subjects performing manual lifting activities using a stoop and a squat technique was used for model validation. A strong association was found between the proposed planar trunk flexion angle and that used by van Dieen and de Looze (r = 0.970). A strong association and a high level of agreement were found between the back extensor muscle moment arm (r = 0.965; bias &lt; 0.001 m; upper limit of agreement (LOA) = 0.002 m; lower LOA &lt; 0.001 m) and the orientation of the line of action (r = 0.970; bias = 2.8°; upper LOA = 5.3°; lower LOA = 0.2°) as computed using the two methods. For both the considered variables, the prediction error fell within the model sensitivity.

Effects of a workplace exercise program on physical capacity and lower back symptoms in hospital nursing assistants: a randomized controlled trial.

Considering the relevance of muscle strength for sustaining good musculoskeletal health among workers who perform physically demanding work, the aim of this study was to evaluate the effectiveness of a therapeutic exercise program on muscle strength and low back symptoms among hospital nursing assistants. One hundred and twenty-nine nursing assistants filled out a questionnaire on personal, occupational information and health status, which allowed the identification of workers able to exercise. Ninety participants were randomly allocated to an intervention and a reference group. The therapeutic exercise program (TEP) lasted 12weeks and included warm-up, strengthening and stretching exercises. Muscle strength of trunk flexors and trunk extensors, hamstring flexibility, and low back symptoms were evaluated before and after the intervention period by two blinded assessors. The comparison between groups was carried out using Mann-Whitney and χ2 tests at a significance level of 0.05. The average participation in the exercise program was 17.5 sessions. Results showed increased trunk flexors muscle strength (p = 0.002; effect size: 0.77), improved pressure pain threshold for dorsal longissimus (p = 0.001; effect size > 0.8), and reduced low back symptoms (p = 0.002; OR = 6.25). No differences between groups were identified for back extensor muscle strength or flexibility. The exercise program applied is a feasible intervention which resulted clinically relevant results for nursing assistants' musculoskeletal health expressed through trunk flexors muscle strength improvement and low back symptoms control among nursing assistants. This RCT brings contribution to the Occupational Health field as the exercise program applied resulted in clinically relevant results for nursing assistants' musculoskeletal health. This study brings contribution especially for low-income and middle-income countries where low back pain and disability can be considered more severe as adequate resources to address the problem are scarce. Thus, we must highlight the importance of low-cost preventive strategies, like exercise programs carried out in hospital settings to avoid the progress of disability among active nursing personnel.

Stretch-induced hypoalgesia: a pilot study.

Objectives Stretching is an intervention often used in various kinds of rehabilitation protocols and the effects on pain sensitivity has sparsely been investigated, especially when addressing potential effects on pain. The objective is to investigate the immediate effects of an axial and peripheral prolonged stretch on pressure pain sensitivity (PPT) and temporal summation (TS) on local and distal sites in healthy subjects. Methods Twenty-two healthy volunteers were recruited to participate in this pilot study. Two prolonged stretching protocols were performed: low back and wrist extensors stretches. PPT and pinprick TS were measured pre- and post-intervention at local and remote sites. Repeated measures analysis of variance (ANOVA) was used to examine the effects and significance of the interventions. Results The low back stretch induced an increase in PPT for both local and remote sites, and the wrist stretch produced a PPT increase only at the local site. TS did not change. Conclusions Low back stretching induced an increase in PPT at both local and remote sites whereas the wrist stretch only increased PPT locally, suggesting hypoalgesia at these sites. Further studies are needed to confirm the effect and mechanisms using randomised, controlled and parallel study design. Considering that pain sensitivity is different than clinical pain, results are difficult to extrapolate to clinical practice. Future studies testing clinical pain are needed to better understand the clinical implication of these results.

Effect Of Scapular Dyskinesis On Scapular Functionality And Back Endurance In Elite Women Handball Players

PURPOSE: In professional handball players, accurate scapulohumeral rhythm is crucial for the prevention of overhead shoulder injuries. Additionally low back strength and endurance transfer power to scapular and upper part of body via posterior fascia chain. The aim of this study was to investigate the difference between handball players with scapular dyskinesis and without scapular dyskinesis regarding to functionality and back endurance. METHODS: Forty-one elite female handball players were included in the study. Sixteen women (mean age: 22.5±6.4yrs BMI: 22.5±2.7kg/m2) who has scapular dyskinesis according to lateral scapular slide test (LSST) as Group 1, 25 women (mean age: 22.5±6.4yrs, BMI:21.8±2.0kg/m2) who has no scapular dyskinesia according to LSST as Group 2 divided into groups. Davies Test and Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST) were used for the measurement of scapular functionality and Sorensen Test for the measurement of back extensor endurance. Mann-Whitney U test was used to compare the mean values between the groups. RESULTS: There were no statistically significant differences in CKCUEST and Davies tests between both groups (p> 0.05). There was statistically significant difference in favor of Group 2 according to Sorensen test between both groups (p = 0.026). CONCLUSION: Endurance of the trunk extensor muscles seems to have influence in scapular dyskinesis in elite female handball players. Besides, functionality of upper extremity in scapular dyskinesis needs to future studies for handball players.

The effect of a 4-week core strengthening program on determinants of wrestling performance in junior Greco-Roman wrestlers: A randomized controlled trial.

Core-strength is vital for Greco-Roman wrestling, although studies have yet to establish the effectives of core-specific training in this sport. To examine the effect of core-specific strength training on determinants of Greco-Roman wrestling performance in elite junior athletes. Twenty state-level, junior, Greco-Roman wrestlers were randomized into a core-specific training group (COR; n= 12) and a control group (CON; n= 8). The COR group undertook a 4-week, core-specific training program concurrently with their typical training program, whilst the CON group completed 4 weeks of typical training only. Both groups completed overhead medicine ball throw (OMBT), Suplexes, bridges and medicine ball chest throw (MBCT) prior to and following the intervention. The COR group demonstrated significantly greater improvement in bridges (p= 0.037; F= 5.046) and OMBT (p< 0.001; F= 26.43) than the CON group, with moderate to large between-group effect sizes (ES = 0.79-2.35). In addition, the effect size calculations were moderate-to-large (0.79-0.87) for Suplex and MBCT, with measures for the COR group greater than the CON group. Accordingly, core-specific training programs should be combined with wrestling-specific conditioning programs to improve back and hip extensor performance in junior Greco-Roman wrestlers.

Is Breast Size Related to Prevalent Thoracic Vertebral Fracture? A Cross-Sectional Study.

ABSTRACTLarge breasts may increase the likelihood of thoracic vertebral fractures by increasing the mechanical loading of the spine. We examined breast size as a factor associated with prevalent thoracic vertebral fractures, also considering its relationship with thoracic kyphosis and upper back extensor muscle endurance. Using a cross‐sectional study, the design measurements collected were thoracic vertebral fractures (≥20% loss in vertebral body height on lateral radiograph), breast size (bra size converted to an ordinal breast size score), BMD (g/cm2 averaged femoral neck, DXA), upper back extensor muscle endurance (isometric chest raise test), body composition (DXA), thoracic kyphosis (radiograph), and upper back pain (numerical rating scale). Correlations and multivariable logistic regression examined relationships between characteristics and their association with vertebral fracture. Participants were 117 healthy postmenopausal women. The 17 (15%) women with ≥1 thoracic vertebral fracture had larger breast size (mean difference [MD]: 2.2 sizes; 95% CI, 0.6 to 3.8 sizes), less upper back extensor muscle endurance (MD: −38.6 s; 95% CI, −62.9 to −14.3 s), and greater thoracic kyphosis (MD: 7.3°; 95% CI, 1.7° to 12.8°) than those without vertebral fracture. There were no between group differences in age, height, weight, and BMD. Breast size (r = −0.233, p = 0.012) and thoracic kyphosis (r = −0.241, p = 0.009) correlated negatively with upper back extensor muscle endurance. Breast size was unrelated to thoracic kyphosis (r = 0.057, p = 0.542). A (final) multivariable model containing breast size (OR 1.85; 95% CI, 1.10 to 3.10) and thoracic kyphosis (OR 2.04; 95%CI, 1.12 to 3.70) explained 18% of the variance in vertebral fracture. Breast size had a significant, but weak relationship with vertebral fracture (R 2 = 0.10), which was independent of BMD and unrelated to thoracic kyphosis. Further work is needed to confirm larger breast size as a risk factor for vertebral fracture. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.