Lumbar Spine Flexion Research Articles

The effect of visual cues at different heights on sit-to-stand movements in people with and without low back pain

BackgroundInvestigating movement strategies that can be utilized to avoid pain-provocation could enhance the management of low back pain episodes. ObjectiveTo assess the effect of visual cues at different heights on the kinematics of sit-to-stand movements, as well as perceived difficulty and pain levels. DesignCross-over design comparing individuals with low back pain to healthy controls. Methods26 asymptomatic controls and 15 individuals with chronic, recurrent low back pain performed 5 sets of 5 sit-to-stand movements. High, middle, and low visual cues were used during sets 2–4. Spinal sagittal plane range of motion, peak spinal flexion and extension angles, and trunk centre of mass velocity were obtained from kinematic data. ResultsThe low cue led to significantly more head and lumbar spine flexion, while the high cue led to significantly more head and thoracic spine extension and increased thoracic spine range of motion. The low back pain group demonstrated a significantly lower vertical trunk centre of mass velocity than the control group during the high cue trials. There was a significant association between higher perceived difficulty scores and lower trunk centre of mass velocity for the low back pain group. Pain scores were not significantly different between cue conditions. ConclusionVisual cues can be used to temporarily change the spinal kinematics of sit-to-stand movements in people with and without low back pain. This could be helpful in clinical practice to encourage more, or less, movement in specific spinal regions, and avoid pain provocation to facilitate functional rehabilitation.

The Effect of Kinesio Taping on Lumbar Kinematic After Static Lumbar Flexion in Healthy Subjects

Introduction: The application of Kinesio taping (KT) is a rehabilitation technique used to provide muscle and joint support and stability, without limiting the range of motion (ROM). No study evaluated the effects of KT on lumbar flexion relaxation phenomenon and kinematic details after static flexion. This study aims to find out the results of KT on erector spinae (ES) muscle activity, flexion relaxation pattern, and trunk, lumbar, and hip range of motion in healthy subjects during static flexion Materials and Methods: This study used a two-factor within-group design. Twenty-two healthy female students participated in this study. We used surface electromyography (EMG) to assess ES muscle activity and measured kinematic information with data from the camera. Variables related to muscle activity and angles in forward bending movement before and after creep were investigated. The test was performed in two situations with and without the use of KT. Results: KT reduced the time of muscle activity during bending. Also, KT increased trunk, and hip angles at the end of forward flexion. In the lumbar extension phase, the ES muscles were activated later Conclusion: KT can prevent the increase of lumbar spine flexion angle due to the creep effect. It can be used to protect the strained viscoelastic structures and increase the involvement of cutaneous receptors. KT can act as a protector in the dynamic stabilization system of lumbar joints in flexion positions in healthy people.

Restricting lumbar spine flexion redistributes and changes total mechanical energy expenditure during lifting

Minimizing lumbar spine flexion during lifting requires greater lower extremity joint motion. However, the effects of these kinematic changes on lumbar and lower extremity joint kinetics are unknown. Further, it is unclear whether the distribution of biomechanical demands throughout the lumbar spine and lower extremity during lumbar spine flexion restricted lifting are modulated by task factors like lift origin height and object mass. This study examined the influence of restricting lumbar spine flexion during lifting on the distribution of biomechanical demands, operationalized as mechanical energy expenditure (MEE), across the lumbar spine and lower extremity joints during lifting tasks. Twenty participants performed a series of lifting tasks that varied by lift origin height, object mass and presence or absence of lumbar spine motion restricting harness. MEE was quantified for the lumbar spine and lower extremity joints and summed across all joints to represent the total MEE. Distributions of MEE were compared across combinations of the three task factors. Total MEE was greater when lifting with restricted spine motion (p < 0.001). MEE was redistributed away from the lumbar spine and predominantly to the hips in the spine restricted conditions (p < 0.001). The nature and magnitude of this effect was modulated by lift origin height for the lumbar spine (p < 0.001) and hips (p < 0.001). Findings demonstrated that biomechanical demands can be shifted from the lumbar spine to the lower extremity when lifting with restricted spine flexion, which might help mitigate overuse injuries through coordinative variability.

The effect of instrument-assisted soft tissue mobilization in lumbar disc herniation: A randomized controlled trial

AimTo investigate the effect of instrument-assisted soft tissue mobilization technique on pain, joint range of motion, functionality and quality of life in patients with lumbar disc herniation. MethodsThis is a double blinded, randomized controlled trial. A total of 60 patients were randomly allocated to either an experimental group [n = 30, age = 46.33 ± 12.96 years] or a control group [n = 30, age = 57.03 ± 9.64 years]. The experimental group received instrument-assisted soft tissue mobilization [3 consecutive days a week for 4 weeks] in addition to conventional physiotherapy [five days a week for 4 weeks]. The control group only received the conventional physiotherapy [five days a week for 4 weeks]. Pain intensity, range of motion of the lumbar spine (flexion, extension, lateral flexion), functional disability related to low back pain and quality of life were assessed at the beginning and end of the study. ResultsThe experimental group showed statistically significant improvements in the range of motion in lumbar area (flexion, extension and lateral flexion values) compared to that shown in the control group (p < 0.05). The mean differences in Oswestry disability index were significantly better in experimental group than in the control group (p < 0.05). There were no significant differences between the two groups in terms of pain and quality of life (p > 0.05). ConclusionsInstrument-assisted soft tissue mobilization, in addition to conservative treatment, can improve range of motion in lumbar area and reduce functional disability in patients with Lumbar Region Disc Herniations.

The Flexion Relaxation Phenomenon in Patients with Radiculopathy and Low Back Pain: A Cross-Sectional Study.

Although the measurements of the lumbar spine and pelvic flexion have shown that subjects with radiculopathy exhibited greater decreases of motion when compared with subjects with low back pain, there is still a lack of evidence regarding the changes in flexion relaxation ratio in patients with radiculopathy. The aims of this study were to investigate the flexion relaxation ratio and flexion of the lumbar spine and pelvis in subjects with low back pain (LBP) and LBP with radiculopathy (LBPR) in comparison with healthy subjects (CG-control group). A total of 146 participants were divided in three groups: LBP patients (54 males; 21 females); LBPR patients (26 males; 11 females); and CG subjects (16 males; 18 females). The lumbar spine and pelvis flexion was recorded using optoelectronic motion capture system. The electrical activity of the erector spinae muscles was assessed by surface electromyography during flexion-extension movements. Comparisons between groups were made using one-way ANOVA tests and Mann-Whithney U test with the level of statistical significance at 0.05. The lumbar and pelvic flexion and electromyography of the erector spinae muscle showed significant differences between LBP and LBPR patients compared to CG. Patients LBPR showed significantly smaller angles of lumbar and pelvic flexion compared to LBP patients and CG. An increase in the erector spinae muscle activity during flexion was also observed in patients with radiculopathy. The increased muscular activity of the erector spinae is related to the reduced flexion of the lumbar spine in order to protect the lumbar spine structure. Measurements of trunk, lumbar spine and pelvic flexion, and the flexion relaxation ratio may allow us to predict better outcomes or responsiveness to treatment of LBPR patients in the future.

Can we enable individuals to reach further down without rounding their backs before beginning a lift? Examining the influence of starting foot and trunk position on reach depth

There is disagreement regarding the efficacy of ‘safe’ lifting recommendations for reducing low back disorder risk. These recommendations commonly focus on minimising lumbar spine flexion, which limits the range of allowable starting lift positions for that person. This study evaluated whether starting postural adaptations could allow a person to reach down further without rounding their lumbar spine before beginning a lift. Reach displacement was measured as participants performed a series of maximal reach tasks under different combinations of stance width, foot orientation and trunk inclination, with their lumbar spine motion restricted. There were no interactions between any of the three postural adaptations or any effect of stance width or trunk inclination. Seventy-nine percent of participants achieved their greatest reach displacement with their feet externally rotated, which contributed to a 4 cm greater reach displacement compared to a neutral foot orientation (p < 0.001). Practitioner summary: This study examined whether aspects of initial posture could influence the ability to adhere to ‘safe’ lifting recommendations across a range of lift heights. As a component of lifting (re)training interventions, practitioners should consider starting lift posture adaptations (e.g. manipulating foot external rotation) to improve capacity to adhere to recommendations.

How to Screen for Lumbar Spine Stiffness in Patients Awaiting Total Hip Arthroplasty

BackgroundThis study aimed to (1) define the prevalence of spinopelvic abnormalities among patients who have hip osteoarthritis (OA) and controls (asymptomatic volunteers) and (2) identify factors that reliably predict the presence of lumbar spine stiffness. MethodsThis is a prospective, cross-sectional, case-cohort study of patients who have end-stage primary hip OA, who underwent primary total hip arthroplasty (THA). Patients were compared with a cohort of asymptomatic volunteers, matched for age, sex, and body mass index (BMI), serving as a control group. Spinopelvic pathologies were defined as: lumbar spine flatback deformity (difference of 10 or more degrees for pelvic incidence minus lumbar lordosis angle), a standing sagittal pelvic tilt of 19° or more and lumbar spine stiffness (lumbar flexion of less than 20° between both postures). ResultsThe prevalence of spinopelvic pathologies was similar between patients and controls (flatback deformity: 16% versus 10%, P = .209; standing pelvic tilt >19°: 17% versus 24%, P = .218; lumbar spine stiffness: 6% versus 5%, P = .827). Age over 65 years-old and standing lumbar lordosis angle less than 45° were associated with high sensitivity and specificity for identifying lumbar spine stiffness (age >65 years: 82% and 66%; standing lumbar lordosis angle <45°: 85% and 73%). ConclusionThe presence of end-stage hip osteoarthritis was not associated with increased prevalence of adverse spinopelvic characteristics compared to matched, asymptomatic volunteers. Age and LLstanding are the strongest predictors of lumbar spine flexion and can guide clinical practice on when to obtain additional radiographs for patients who have hip OA before arthroplasty to identify at-risk patients. Level of EvidenceII (prospective, cohort study).

Ultrasound Shear Wave Elastography Quantitatively Assesses Tension Changes of Supraspinous/Interspinous Ligament Complex Under Varied Loads.

Although interspinous and supraspinous ligaments of the lumbar spine are thought to contribute to spinal stability, little is known about their dynamic biomechanics. We demonstrate that shear wave elastography (SWE) offers a novel technique to noninvasively and quantitatively evaluate posterior spinous ligament complex functional loading and stiffness in different physiologic positions. We performed SWE and measured the length of the interspinous/supraspinous ligament complex in cadaveric torsos (N = 5), isolated ligaments (N = 10), and healthy volunteers (N = 9) to obtain length and shear wave velocity measurements. For cadavers and volunteers, SWE was utilized in 2 lumbar positions: lumbar spine flexion and extension. In addition, SWE was performed on isolated ligaments undergoing uniaxial tension to correlate shear wave velocities with experienced load. Average shear wave velocity in cadaveric supraspinous/interspinous ligament complexes increased for lumbar levels (23%-43%) and most thoracic levels (0%-50%). This corresponded to an average increase in interspinous distance from extension to flexion for the lumbar spine (19%-63%) and thoracic spine (3%-8%). Volunteer spines also demonstrated an average increase in shear wave velocity from extension to flexion for both the lumbar spine (195% at L2-L3 to 200% at L4-L5) and thoracic spine (31% at T10-T11). There was an average increase in interspinous distance from extension to flexion for the lumbar spine (93% at L2-L3 to 127% at L4-L5) and thoracic spine (11% at T10-T11). In isolated ligaments, there was a positive correlation between applied tensile load and average shear wave velocity. This study creates a foundation to apply SWE as a noninvasive tool for assessing the mechanical stiffness of posterior ligamentous structures and has potential applications in augmenting or evaluating these ligaments in patients with spine pathology. The interspinous and supraspinous ligaments are critical soft tissue supports of the posterior lumbar spine. Disruption of these structures is thought to have a negative impact on spinal stability in trauma and spine deformities.

Evaluation of the effects of a novel exercise program in the treatment of low back pain in women working in a seated position: A randomized trial.

Low back pain (LBP) in sedentary workers is an increasing problem. Hyperlordosis or hypolordosis of the lumbar spine may be one of the causes of LBP. Various exercise programs are used in the prevention of LBP, but they do not consider individualization for diagnosed hyperlordosis or hypolordosis of the lumbar spine. The purpose of this study was to evaluate the effect of the authors' original exercise program aimed at reducing hyperlordosis or increasing hypolordosis. Sixty women aged 26 to 40 working in a sedentary position participated in the study. The sagittal curvature and the range of motion of the lumbar spine flexion were measured with the Saunders inclinometer, and the level of LBP was evaluated using the VAS scale. Subjects were randomly divided into two groups that participated in a 3-month exercise program developed by the authors. The first group performed exercises adjusted to the diagnosed hyperlordosis or hypolordosis, and the second group performed the same exercises regardless of the lumbar lordosis angle. The study was conducted again after completing the exercises. There was a statistically significant difference between the groups (p< 0.0001) in the level of pain, with better results in the group where individualized exercise was used - 60% of the participants reported complete absence of LBP. The lumbar lordosis angle was within normal limits in 97% of the subjects in the first group, and in 47% of the subjects in the second group. The results of this study confirm the validity of using individualized exercises with regard to diagnosed hyperlordosis or hypolordosis of the lumbar spine in order to achieve better analgesic and postural correction effects.

Effect of axial compression on stiffness and deformation of human lumbar spine in flexion-extension

Objective The goal of this study was to evaluate the effect of axial compression, employed with a follower-load mechanism, on the response of the lumbar spine in flexion and extension bending. Additional goals include measurement of both the kinetic (stiffness) and kinematic (deformation distribution) responses, evaluating how the responses vary across specimens, and to develop response corridors that can be used to evaluate human body models (HBMs) and anthropomorphic test devices (ATDs). Methods Seven mid-sized male adult lumbar spines (T12-S1) from postmortem human surrogates were tested in subinjurious flexion and extension bending with 0, 900, and 1800 N of superimposed axial compression. Tests were performed in load-control with a 6-DOF robotic test system that applied pure flexion and extension moments to the specimens, and axial compression was directed along the spine’s curvature via a follower load mechanism powered by force-controlled linear actuators. Load-deformation response data were captured and used to characterize the kinetic response of the lumbar spine in flexion/extension, and how it varies with axial compression. Individual vertebral kinematics were captured using 3D motion capture and the data was used to illustrate the distribution of bending deformation across each intervertebral joint of the spine, as well has how that distribution changes with axial compression. These response data were used to develop elliptical path-length parameterized response corridors for surrogate biofidelity evaluation. Results The lumbar spine was found to be generally stiffer in extension than in flexion, but this difference decreased with increasing axial compression. The lumbar spine exhibited a nonlinear kinetic (moment vs. angle) response in flexion that became more linear and stiffer with the addition of axial compression. In flexion without axial load, the majority of the bending deformation occurred at the L5-S1 joint, whereas in extension, deformation was more evenly distributed across the different intervertebral levels, but the locus of deformation was located in the mid-proximal lumbar at L2-L3. Conclusions The superposition of axial compression in the lumbar spine affects the kinetic and kinematic response of the lumbar spine in flexion and extension. The response data and approach detailed in this study permit better assessment of ATD and HBM biofidelity.

Biomechanical analysis of breastfeeding positions and their effects on lumbopelvic curvatures and lumbar muscle responses

This study aimed to analyze the position of the lumbopelvic region and lumbar muscle activity in the most common breastfeeding positions. We recorded the curvatures of the lumbar spine and pelvis by means of an electrogoniometer, and the muscle activation levels of the erector spinae with electromyography, in 34 women in erect standing and breastfeeding their children in several positions. Both side lying and clutch-hold positions showed a greater degree of lumbar spine flexion compared to standing. In all sitting postures it was observed that the pelvis was placed in retroversion when compared to standing and side lying. In muscle activity, it was observed that the activation intensity of the right erector in the right side-supported side lying position was significantly lower compared to the rest of breastfeeding postures and standing. Side lying may be a better position to avoid muscle fatigue.

Human Lumbar Spine Injury Risk in Dynamic Combined Compression and Flexion Loading.

Anticipating changes to vehicle interiors with future automated driving systems, the automobile industry recently has focused attention on crash response in novel postures with increased seatback recline. Prior research found that this posture may result in greater risk of lumbar spine injury in the event of a frontal crash. This study developed a lumbar spine injury risk function (IRF) that estimated injury risk as a function of simultaneously applied compression force and flexion moment. Force and moment failure data from 40 compression-flexion tests were utilized in a Weibull survival model, including appropriate data censoring. A mechanics-based injury metric was formulated, where lumbar spine compression force and flexion moment were normalized by specimen geometry. Subject age was incorporated as a covariate to further improve model fit. A weighting factor was included to adjust the influence of force and moment, and parameter optimization yielded a value of 0.11. Thus, the normalized compression force component had a greater effect on injury risk than the normalized flexion moment component. Additionally, as force was nominally increased, less moment was required to produce injury for a given age and specimen geometry. The resulting IRF may be utilized to improve occupant safety in the future.

Effects of trunk extensor muscle fatigue on repetitive lift (re)training using an augmented tactile feedback approach

Augmented tactile and performance feedback has been used to (re)train a modified lifting technique to reduce lumbar spine flexion, which has been associated with low back disorder development during occupational repetitive lifting tasks. However, it remains unknown if the presence of trunk extensor neuromuscular fatigue influences learning of this modified lifting technique. Therefore, we compared the effectiveness of using augmented tactile and performance feedback to reduce lumbar spine flexion during a repetitive lifting task, in both unfatigued and fatigued states. Participants completed repetitive lifting tests immediately before and after training, and one-week later, with half of the participants completing training after fatiguing their trunk extensor muscles. Both groups demonstrated learning of the modified lifting technique as demonstrated by increased thorax-pelvis coordination variability and reduced lumbar range of motion variability; however, experiencing trunk extensor neuromuscular fatigue during lift (re)training may have slight negative influences on learning the modified lifting technique.

Kinematic adaptations to restricting spine motion during symmetrical lifting

When lifting an object from the ground a person has many possible whole-body movement solutions to accomplish the task. It is unclear why lifters use most of their available lumbar spine flexion range-of-motion despite many ergonomic guidelines advising against doing so. Experimentally restricting spine motion and observing compensatory movement strategies is one approach to address this knowledge gap. A kinematic analysis was performed on 16 participants who completed symmetrical lifting tasks with and without wearing a spine motion-restricting device. Sagittal trunk, lumbar spine, and lower extremity kinematics, along with stance width and foot orientation in the transverse plane were evaluated between restricted and unrestricted lifting conditions. Restricting spine motion required greater ankle dorsiflexion (p < 0.001), knee flexion (p < 0.001), and hip flexion (p < 0.001) motion in comparison to unrestricted lifting. Motion was reallocated such that hip flexion showed the largest increase in restricted lifting, followed by ankle dorsiflexion, then knee flexion compared to unrestricted lifting. Trunk inclination decreased (i.e., more upright) in restricted compared to unrestricted lifting (p < 0.001). Neither stance width (p = 0.163) nor foot orientation (p = 0.228) were affected by restricting spine motion. These adaptive movements observed indicate lower extremity joint motion must be available and controlled to minimize lumbar spine flexion during lifting.

P16. Biomechanical assessments of the spine during a 2000M ergometer row test

<h3>BACKGROUND CONTEXT</h3> Ergometer rowing has gained popularity as a "low-impact" form of exercise. Lumbar spine injuries are the most common injury in rowers. Previous studies have shown ergometer training to be associated with an increased risk of injury. Muscular fatigue and spine range of motion may correlate to pain or injury in ergometer rowing. <h3>PURPOSE</h3> The purpose of the present study is to utilize 3D motion capture and electromyography (EMG) assessments to 1) evaluate how muscular activation relates to lumbar spine mechanics; 2) determine the impact of fatigue on back muscle activation and biomechanics. <h3>STUDY DESIGN/SETTING</h3> Prospective analysis. <h3>PATIENT SAMPLE</h3> Seventeen rowers (M=8, F=9) with a mean age of 38 ± 9.1 years and a VO2 max of 44.4 ± 7.8 ml·kg·min-1. <h3>OUTCOME MEASURES</h3> Pull force, kinematics and muscle activation were recorded at 200m, 600m, 1000m, 1400m and 1800m distances. Spine flexion (degrees) was investigated. <h3>METHODS</h3> Seventeen rowers (m=8, F=9; age=38±9.1 years, VO2max=44.4±7.8 ml·kg·min-1) participated and performed a 2000-meter row on an ergometer. Pull force, kinematics and muscle activation were recorded using a load cell, motion capture system and a wireless EMG, respectfully. Data was recorded at 200m, 600m, 1000m, 1400m and 1800m distances. Spine flexion was calculated at three points in the sagittal plane and labeled as upper-, mid- and lower-spine. A mixed-model ANOVA repeated on row distance and a Tukey's post-hoc test was used to compare biomechanical assessments. Type-I error was set at a=0.05. <h3>RESULTS</h3> Average time to complete the test was 8.4 ± 1.0 min. Trapezius and mid-spinal erector activation was maintained through the row. A steady decrease in mean and peak latissimus dorsi activation was observed with increasing distance (p < 0.05), paired with an increase in peak lumbar spinal erector activation (p < 0.05), indicating fatigue of the upper back musculature followed by compensatory reliance on low back muscles to maintain/increase force. Upper spinal flexion (min and max) increased by 1000m, indicating an increase in the overall state of flexion with progressing distance (p < 0.05). Mid-spinal flexion demonstrated increased min flexion (indicating reduced peak extension) beginning at 1400m (P < 0.05). Lumbar spine flexion was maintained throughout the row, indicating that the primary mechanics fatigue change was a result of upper back rounding due to upper back muscle fatigue. Results indicate that low back pain and injuries associated with rowing may not be because of altered flexion/extension of the lumbar spine but rather, a result of increased workload placed on low back musculature to compensate fatiguing muscles and changes in the row mechanics of the upper and mid spine. Although ergometer rowing is often considered "low-impact," given the high number of contractions over a short time (<10min), it may be advisable for rowers to avoid multiple days of fatiguing row ergometer training per week. <h3>CONCLUSIONS</h3> The present findings will provide greater insight into the potential mechanisms of fatigue during ergometer rowing. Results will also give medical professionals a better understanding of the origins and presentation of soft tissue injuries in the spine in recreational rowers. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Effect of incremental intensities on the spinal morphology and core muscle activation in competitive cyclists

ABSTRACT Cycling is a sport where cyclists predominantly adopt a sitting posture, with the trunk tilted forward. This posture requires a high volume of training and duration in several intensities of effort. This study aims to: 1) evaluate the behaviour of the thoracic and lumbar spine flexion and sacral inclination in the sagittal plane, the thoracic and lumbar spine flexion in the frontal plane, and the trunk torsion in the transverse plane; 2) compare the activation of the core muscles as the intensity of effort increases during an incremental test in cycling, and 3) identify which core muscle has a greater activation in each intensity zone. The spinal posture and the activation of the eight core muscles were evaluated in twelve competitive cyclists during incremental cycling intensities. Thoracic and lumbar spine flexion and sacral inclination statistically increased as the intensity of effort increased (Start < VT1 < VT2 < VO2max). A significant increase in muscle activation was observed in all core muscles evaluated as the intensity increased. The rectus abdominis showed statistically significant greater muscle activation than the other core muscles evaluated. In conclusion, as the intensity of effort in cycling increases, cyclists significantly increase the thoracic and lumbar spine flexion, the sacral inclination in the sagittal plane, the thoracic and lumbar spine flexion in the frontal plane, trunk rotation in the transverse plane, as well as the activation of the core muscles.

ID:16024 Lead Migration During Spinal Cord Stimulation Trial Using Temporary Leads After Lumbar Spine Flexion

SCS trials using temporary percutaneous leads are known to have migration risk, which might reduce therapy efficacy and program options available to the patient. This retrospective analysis describes migration and the benefit of perioperative flexion in a cohort of subjects in the Stimgenics Randomized Controlled Trial (RCT) with available data.

The Stoop-Squat-Index: a simple but powerful measure for quantifying whole-body lifting behavior

BackgroundMost of the studies evaluating lifting behavior only focus on very localized parameters such as lumbar spine flexion, while evaluations of whole-body strategies are largely lacking. To enable relatively simple evaluations of whole-body strategies, this study aimed at developing a novel index for quantifying the stoop-squat behavior, and to establish normative values of the index for healthy pain-free adults.MethodsA novel index, the Stoop-Squat-Index, was developed, which describes the proportion between trunk forward lean and lower extremity joint flexion, with possible values ranging from 0 (full squat lifting) to 100 (full stoop lifting). To enable the interpretation of the index in a real-life setting, normative values for lifting a moderately-weighted object (15-kg-box) with a full squat and a full stoop technique were established using motion capture data from 30 healthy pain-free individuals that underwent motion analysis of squat and stoop lifting in the context of a previously conducted study.ResultsThe results showed mean index values of lower than 30 and higher than 90 for the most relevant phases of the squat and stoop movements, respectively, with mean index values differing significantly from each other for the full duration of the lifting phases.ConclusionsThe main advantages of the index are that it is simple to calculate and can not only be derived from motion capture data but also from conventional video recordings, which enables large-scale in-field measurements with relatively low expenditure. When used in combination with lumbar spine flexion measurements, the index can contribute important information, which is necessary for comprehensively evaluating whole-body lifting strategies and to shed more light on the debate over the connection between lifting posture and back complaints.

Application of Wearable Sensors Technology for Lumbar Spine Kinematic Measurements during Daily Activities following Microdiscectomy Due to Severe Sciatica.

Simple SummaryThe recurrence rate after lumbar spine disc surgeries is estimated to be 5–15%. Lumbar spine flexion of more than 10° is mentioned in the literature as the most harmful load to the operated disc level that could lead to recurrence during the first six postoperative weeks. The purpose of this study is to quantify flexions during daily living following such surgeries, for six weeks postoperatively, using wearable sensors technology. These data determine the patients’ kinematic pattern, reflecting a high-risk factor for pathology recurrence. The operated patients were measured to have 30% normal lumbar motion after the first postoperative week, while they were restored to almost 75% at the end of the sixth, respectively. Further in vitro studies should be carried out using these data to identify if such kinematic patterns could lead to pathology recurrence.Background: The recurrence rate of lumbar spine microdiscectomies (rLSMs) is estimated to be 5–15%. Lumbar spine flexion (LSF) of more than 10° is mentioned as the most harmful load to the intervertebral disc that could lead to recurrence during the first six postoperative weeks. The purpose of this study is to quantify LSFs, following LSM, at the period of six weeks postoperatively. Methods: LSFs were recorded during the daily activities of 69 subjects for 24 h twice per week, using Inertial Measurement Units (IMU). Results: The mean number of more than 10 degrees of LSFs per hour were: 41.3/h during the 1st postoperative week (P.W.) (29.9% healthy subjects-H.S.), 2nd P.W. 60.1/h (43.5% H.S.), 3rd P.W. 74.2/h (53.7% H.S.), 4th P.W. 82.9/h (60% H.S.), 5th P.W. 97.3/h (70.4% H.S.) and 6th P.W. 105.5/h (76.4% H.S.). Conclusions: LSFs constitute important risk factors for rLDH. Our study records the lumbar spine kinematic pattern of such patients for the first time during their daily activities. Patients’ data report less sagittal plane movements than healthy subjects. In vitro studies should be carried out, replicating our results to identify if such a kinematic pattern could cause rLDH. Furthermore, IMU biofeedback capabilities could protect patients from such harmful movements.

What Are the Physical Demands of Sexual Intercourse? A Systematic Review of the Literature

The aim of this study was to systematically review the literature investigating the physical demands of sexual intercourse and to synthesize the evidence related to this research topic. Original studies published on PubMed, Scopus, and Web of Science up until April 2020 were examined. The Effective Public Health Practice Project scale was used to assess the methodological quality of each study. Eighteen studies analyzed physical demands during sexual intercourse through the physiological demands (n = 14) and kinematics (n = 4) of sexual intercourse. Sexual intercourse can elicit an energy expenditure of ~ 100 kcal (or ~ 6 metabolic equivalent units, METs) during the activity, mean heart rates between ~ 90 and ~ 130 beats per minute (bpm), and peak heart rates up to ~ 170 bpm. However, these physical demands may vary depending on health status, intercourse position, activity duration, intercourse phase, and sex differences. The movement pattern was cyclic in all positions and the greatest demands in lumbar spine flexion were found in the missionary positions for women. Missionary and side-lying positions elicited the greatest lumbar flexion movement in men. Regarding the movement of the hip joint during sexual intercourse, flexion, abduction, and external rotation mainly characterized the woman’s movement while external rotation did so in the man. In conclusion, sexual intercourse may elicit moderate intensity physical demands, but these demands vary depending on contextual variables. In addition, not only studies combining physiological and kinematic analyses are necessary but also more high-quality studies need to be published in order to have a better understanding of the physical demands of sexual intercourse.