Trunk Inclination Research Articles

The Relationship Between the Shape of the Spine and the Width of Linea Alba in Children Aged 6-9 Years. Case-Control Study.

IntroductionCivilization development coupled with contemporary lifestyle leads to a systematic increase in postural disorders. An analysis of factors that may provoke postural disorders indicates that such a stimulus may be the diastasis of the rectus abdominis muscles. Moreover, abnormal activity of the rectus abdominis muscles may affect balance disorders through reduced spinal stabilization and disturbed body statics. There is an increase in body posture abnormalities between the ages of 6 and 9 related to new school duties.Purpose of the StudyThe purpose of the study was to evaluate the relationship between the shape of the spine and the width of the linea alba in children aged 6–9 years.Material and MethodThe study was designed to evaluate parameters determining the shape of the spine, and the width of the linea alba in healthy children aged 6–9 years. The study participants were divided into two groups based on the width of the linea alba. The study group with the width of the linea alba >10 mm and the control group with the width of the linea alba ≤ 10 mm. The study group were included 37 children and the control group 24 children. The examination of the linea alba width was performed by a radiology specialist using a linear transducer and SAOTE- My Lab Classc-type ultrasound at rest and during contraction of the rectus abdominis muscles. Parameters describing the shape of the spine were measured using the Diers Formetric 4D system: trunk inclination, trunk imbalance, pelvis tilt, pelvic torsion, kyphotic apex, lordotic apex, kyphotic angle, lordotic angle, rotation angle, trunk torsion, lateral deviation. The obtained results were statistically analyzed using a Paired t test for comparison of differences between the results in the study and control groups and Pearson's test to assess the correlation between the width of the linea alba and parameters describing spinal alignment.ResultsIn both groups, the parameters describing the shape of the spine did not differ from the norms accepted as typical for the age norm. The only statistically significant difference between the study and control group concerned the trunk inclination, which was negative in the study group, signifying a shift of the entire spine axis backwards beyond the vertical.ConclusionsThere is a correlation between the shape of spine and the width of the linea alba in terms of selected parameters determining the body posture in the sagittal plane, which concern: the position of the lumbar lordotic apex, trunk inclination and the depth of the lumbar lordotic angle. The width of the linea alba is not explicitly related to abnormalities of pelvic and spinal alignment in the frontal and transverse planes.

Effectiveness and usability of real-time vibrotactile feedback training to reduce postural exposure in real manual sorting work

Vibrotactile feedback training may be used as a complementary strategy to reduce time in demanding postures in manual handling. This study evaluated the short- and medium-term effects of concurrent posture-correction vibrotactile feedback training on trunk inclination exposure in real manual sorting work. Fifteen warehouse workers completed the training and the follow-up sessions. Trunk inclination angles were recorded using the ambulatory Smart Workwear System. Questionnaires were used for assessing system usability, perceived physical exertion and work ability. The results showed reduced time in trunk inclination >30°, >45° and >60°, and reductions in the 90th, 95th and 99th percentile trunk inclination angles, when receiving feedback and immediately after feedback withdrawal. No significant reduction was retained after one and three weeks. The wearer comfort was scored high, and the feedback did not increase the perceived cognitive demands. No significant effects attributed to changed trunk inclination exposure were observed for perceived physical exertion or work ability. The training program has the potential of contributing to reduced trunk inclination exposure in the short-term. Future studies are needed to evaluate if improvements of the feedback training can transfer the short-term results to retained median- and long-term effects. Practitioner Summary: A two-day training program with concurrent posture-correction vibrotactile feedback can contribute to reduced exposure of trunk inclination in real manual sorting work in the short term. More research is needed on how to design the feedback training programs in order to be effective in the long term.

Non-Invasive Neuromodulation in the Rehabilitation of Pisa Syndrome in Parkinson's Disease: A Randomized Controlled Trial

BackgroundPisa syndrome (PS) is a frequent postural complication of Parkinson's disease (PD). PS poorly responds to anti-parkinsonian drugs and the improvement achieved with neurorehabilitation tends to fade in 6 months or less. Transcranial direct current stimulation (t-DCS) is a non-invasive neuromodulation technique that showed promising results in improving specific symptoms in different movement disorders.ObjectivesThis study aimed to evaluate the role of bi-hemispheric t-DCS as an add-on to a standardized hospital rehabilitation program in the management of PS in PD.MethodsThis study included 28 patients with PD and PS (21 men, aged 72.9 ± 5.1 years) who underwent a 4-week intensive neurorehabilitation treatment and were randomized to receive: i) t-DCS (t-DCS group, n = 13) for 5 daily sessions (20 min−2 mA) with bi-hemispheric stimulation over the primary motor cortex (M1), or ii) sham stimulation (sham group, n = 15) with the same duration and cadence. At baseline (T0), end of rehabilitation (T1), and 6 months later (T2) patients were evaluated with both trunk kinematic analysis and clinical scales, including UPDRS-III, Functional Independence Measure (FIM), and Numerical Rating Scale for lumbar pain.ResultsWhen compared to the sham group, the t-DCS group achieved a more pronounced improvement in several variables: overall posture (p = 0.014), lateral trunk inclination (p = 0.013) during upright standing position, total range of motion of the trunk (p = 0.012), FIM score (p = 0.048), and lumbar pain intensity (p = 0.017).ConclusionsOur data support the use of neuromodulation with t-DCS as an add-on to neurorehabilitation for the treatment of patients affected by PS in PD.

A Fully-Immersive Virtual Reality Setup to Study Gait Modulation.

Objective: Gait adaptation to environmental challenges is fundamental for independent and safe community ambulation. The possibility of precisely studying gait modulation using standardized protocols of gait analysis closely resembling everyday life scenarios is still an unmet need.Methods: We have developed a fully-immersive virtual reality (VR) environment where subjects have to adjust their walking pattern to avoid collision with a virtual agent (VA) crossing their gait trajectory. We collected kinematic data of 12 healthy young subjects walking in real world (RW) and in the VR environment, both with (VR/A+) and without (VR/A-) the VA perturbation. The VR environment closely resembled the RW scenario of the gait laboratory. To ensure standardization of the obstacle presentation the starting time speed and trajectory of the VA were defined using the kinematics of the participant as detected online during each walking trial.Results: We did not observe kinematic differences between walking in RW and VR/A-, suggesting that our VR environment per se might not induce significant changes in the locomotor pattern. When facing the VA all subjects consistently reduced stride length and velocity while increasing stride duration. Trunk inclination and mediolateral trajectory deviation also facilitated avoidance of the obstacle.Conclusions: This proof-of-concept study shows that our VR/A+ paradigm effectively induced a timely gait modulation in a standardized immersive and realistic scenario. This protocol could be a powerful research tool to study gait modulation and its derangements in relation to aging and clinical conditions.

Kinematic evaluation and reliability assessment of the Nine Hole Peg Test for manual dexterity

BackgroundThe Nine Hole Peg Test (NHPT) is one of the most frequently used tools to assess manual dexterity. However, no kinematic parameters are provided to describe the quality of the motor performance, since time is the only score. PurposeTo investigate test-retest and intra-rater reliability, correlation with clinical test score, and discriminant validity of kinematic indexes during NHPT. Study DesignA clinical measurement study. MethodsTwenty-five healthy right-handed volunteers performed the NHPT. An experienced physiotherapist administered two sessions at a 6-hour interval with two trials for dominant and non-dominant upper limbs. An optoelectronic system was used to detect NHPT performance, which was divided into nine consecutive peg-grasp, peg-transfer, peg-in-hole, hand-return phases, and one final removing phase. Outcome measures were total and single phases times, normalized jerk, mean, peak and time-to-peak of velocity, curvature index during peg-grasp and hand-return phases, and trunk 3D displacement. The statistical analysis included Intraclass Correlation Coefficients (ICCs) for test-retest and intra-rater reliability, Pearson's coefficients for correlation with the NHPT score, and paired t-tests for discriminant validity. ResultsTest-retest reliability was excellent for trunk rotation (ICC: 0.91) and good to moderate for the other indexes (ICCs: 0.89-0.61). Intra-rater reliability was excellent for total and removing times (ICCs: 0.91 and 0.94) and good to moderate for the other indexes (ICCs: 0.84-0.66), except for trunk inclination (ICC: 0.37). NHPT phases, normalized jerk, mean velocity, peak of velocity, time-to-peak and curvature index correlated with total time (r-score: 0.8-0.3). NHPT phases and most kinematic indexes discriminated the dominant from non-dominant upper limb, with the greatest effect size for normalized jerk during hand-return (d = 1.16). ConclusionsKinematic indexes during NHPT can be considered for manual dexterity assessment. These indexes may allow for the detection of kinematic changes responsible for NHPT score variations in healthy subjects or patients with upper limb impairments.

Measuring pandemic home-work conditions to determine ergonomic recommendation relevance

BACKGROUND: Computer-intensive office work associations with health challenges may intensify following COVID-19 pandemic-related changes to home-based office work. OBJECTIVE: To determine working conditions, perception and physical elements affecting health after pivoting to full time home-work. METHODS: An online questionnaire addressed physical, productivity, motivation, and work-practice factors. Photos of the worker in their home-work environment showed side and front-back perspectives. RESULTS: Sixteen questionnaires were received, and 12 respondents supplied photos. Home and office workplace differences varied. Ten felt productivity was affected, most often positively. Four noted increased pain or fatigue intensity, particularly in the eyes, neck / head, lower back, and shoulders. Working posture was not optimal; six didn’t use traditional chair-sitting for up to half the day. Forward and backward trunk inclination accounted for at least 10% of the workday for 12 respondents; lateral inclination affected ten and eight had unsupported legs. Fifteen used an adjustable chair, but photos revealed ergonomic recommendations were not consistently followed. Fourteen participants communicated regularly by telephone, eight only for moderate duration and ten using adapted telephone equipment. Half of the ROSA scores were high. CONCLUSIONS: Workers forced into telework during the pandemic experience positive and negative impacts. Postures vary more than in offices, potentially increasing health risk.

Relationship of Quantitative Measures of Jumping Performance with Gross Motor Development in Typically Developed Preschool Children.

Jumping is a key movement developing in the preschool period, but limited studies have reported the determinants of jumping performance and its relationship with gross motor development. This study aimed to determine the correlations among jumping performance, quantitative parameters of jumping, and gross motor development in preschool children. Twenty-one preschool children were recruited from one kindergarten, and fifteen of them with complete data were further analyzed. The quantitative parameters of standing long jump (SLJ) and standing vertical jump (SVJ) were measured using a video-based motion capture system. The gross motor development was measured using the Preschooler Gross Motor Quality Scale (PGMQ). The Spearman’s rho value and a linear regression model were used to determine the relationships among the jumping performance, the quantitative measures, and the total PGMQ scores. The results indicate that the jumping performances were significantly correlated with the takeoff velocity, which was predicted by trunk inclination before takeoff in SLJ and by the ranges of trunk inclination during jumping in SVJ. Regression analysis showed that the preschool children with higher normalized jump height had better gross motor development, and that the jump performance and the gross motor development were directly or indirectly predicted by the slope of the hip-to-ankle angle plot during pre-takeoff. In conclusion, this study identifies key components of jumping in jumping performance and gross motor development in preschool children for physical education.

Comparison of flexion relaxation phenomenon between female yogis and matched non-athlete group

BackgroundTrunk flexion is a common exercise during daily activities. Flexion relaxation phenomenon (FRP) occurs during forward bending in which there is a sudden silence of erector spinae (ES) muscles. The pattern of forward bending differs in yoga practitioners. This learned pattern probably predisposes yogis to injuries. The hypothesis of this study was that FRP differs in yogis in comparison to non-yogis individuals.MethodsThis observational cross-sectional study was performed on 60 women assigned into yogis and non-athlete groups. Each participant was asked to bend forward and then return to the initial position. ES activity was recorded at L3 level, 4 cm from mid line during the trial. Trunk inclination and lumbar flexion angles were calculated at FRP onset and cessation moments.ResultsThe FRP occurred in 80% of yoga practitioners in comparison to 96.7% in the control group. Trunk inclination angle was significantly greater at FRP initiation in yogis compared to control group. Lumbar flexion angle was not different between the groups.ConclusionsIt is concluded that the altered pattern of forward bending observed in yogis may change patterns of ES muscles activity if it becomes part of a person's daily lifestyle which might predispose these muscles to fatigue and subsequent injuries; however, further studies are warranted for clarification.

Characteristics of Body Posture in the Sagittal Plane in 8–13-Year-Old Male Athletes Practicing Soccer

Background: An important part of a healthy lifestyle for children and adolescents is exercising to satisfy the natural need for physical activity. However, young athletes should take special care when they participate in intense physical training, to ensure their proper physical development. The aim of this study was to evaluate the body posture in the sagittal plane of soccer players in comparison with healthy untrained peers. Methods: A total of 245 young males aged 8–13 who participated in the study were divided into two groups: “Group F—Footballer”, elite youth soccer players comprising 132 male athletes, and “Group C—Control group”, consisting of 113 boys from primary schools. The elite, youth soccer players played and trained in the Gold Standard Certificate Academy for their age group and belonged to the top 1% of all players from their category, respectively (Polish Soccer Association (PZPN)). The control group consisted of healthy boys from primary schools in Wroclaw not practicing any sport. A photogrammetric method based on the projection moiré phenomenon was used to assess the body posture in all subjects. Results: The analysis showed statistically significant differences in body posture parameters in the sagittal plane between the trained (F) and non-trained (C) groups. In all age groups, a significantly higher value of the upper thoracic angle and a lower value of the trunk inclination angle were observed in the football players’ group. Significant differences were also observed for the thoracic spine in each age group. In the groups of 8–9 and 12–13 years, they concerned the angle of thoracic kyphosis, and in the group of 10–11-year-old, the depth of thoracic kyphosis. In the group of children with ages 8–9 and 10–11, significantly higher values of lumbosacral angle and upper thoracic angle were observed in the group of soccer players. Conclusions: The soccer training load can influence the anterior–posterior curvature of the spine. In the group of footballers in all age groups, higher angular values of thoracic kyphosis and greater tilt of the torso forward were found, compared with their untrained peers. There were also significant differences in body posture between children of different ages, both in the group of footballers and in the group of untrained children. In the group of footballers, the differences concerned mainly the size of the lumbosacral angle and the depth of both curves, which decreased with the age of the players. A similar phenomenon was observed in the group of untrained boys but only in children in the older age groups.

The importance of the size of the trunk inclination angle in the early detection of scoliosis in children

BackgroundEarly detection of idiopathic scoliosis is one factor in determining treatment effectiveness. Therefore, the aim of this study was to assess the importance of the size of the trunk inclination angle (ATI) for the early detection of scoliosis in preschool- and school-age children, taking into account the location and size of the spine curvature.MethodsThe study included a group of 216 children (mean age 11.54 years, standard deviation ± 3.05), who had previously untreated idiopathic scoliosis and a Cobb angle of ≥ 10°. The ATI values were compared with the corresponding Cobb angle values. The results of the ATI-Cobb correlation were compared to the ATI thresholds of 5° and 7°.ResultsIn the age groups 6–9, 10–12 and 13–17 years, the method sensitivity for the ATI ≥ 7° criterion was low at 33.90%, 27.69% and 51.29% (p < 0.05), respectively, while for the ATI ≥ 5° criterion, it was 67.8%, 69.23% and 93.48% (p < 0.05), respectively. With respect to location, significantly more frequent misdiagnoses (p < 0.05) were related to the lumbar and thoracolumbar (regions) sections of the spine in the groups aged 6–9 and 10–12 for ATI ≥ 7°; while no significant relationship was found at ATI ≥ 5°. For both ATI levels, the most frequent cases of mis- or undiagnosed scoliosis were observed among children with a Cobb angle of 10°-14° (p = 0.004).ConclusionA low predictive ATI value was demonstrated regarding scoliosis detection for the ATI 7° criterion in children aged 6–9 and 10–12 years, particularly for the lumbar and thoracolumbar locations. Adoption of the threshold of ATI 5° in screening tests for children aged 6–12 years, as well as for lower locations of scoliosis, may be more effective in the early detection of scoliosis.Trial registration.This study was approved by the Jan Dlugosz University in Czestochowa Ethics Committee KE-U/7/2021, and conducted under the Declaration of Helsinki.

How Does the pH of Tree Bark Change with the Presence of the Epiphytic Bryophytes from the Family Orthotrichaceae in the Interaction with Trunk Inclination?

The pH of tree bark is affected by many factors, amongst them epiphytic bryophytes changing in their active state environment. Thus, we hypothesized that bryophytes can change bark acidity, dependently of the inclination of the branches, as inclination affect the water regime and particle deposition. We measured the pH under bryophyte cushions and compared it to nearby naked bark. Additionally, we compared results with experimental bark covering with neutral cover. We found that the pH of naked bark declines with decreasing inclination of trunks. Although bryophyte cover did not generally change the pH of the bark, there was a significant interaction with inclination: with higher inclination, bryophytes decrease the pH reaction of bark, while with lower inclination they increase it. One possible explanation may lie in changes to alkaline particle deposition, or conversely in the acidification of the bark by leaching. In addition, an experiment with a neutral cover showed that naked bark covering would substantially increase pH. As, on average, bryophytes do not change the pH of bark, there can be mutual interference between the alkalizing effect of the bark cover itself and the acidifying biological effect of bryophytes.

Effect of Low Versus High-Heeled Footwear on Spinopelvic Alignment at Different Phases of Menstrual Cycle in Young Adult Women: A Biopsychosocial Perspective.

High-heeled shoes adversely affect spinal curvature, increase the risk of low back pain, and disturb the normal gait pattern. The purpose of this study was to examine, from a biopsychosocial point of view, the combined effect of wearing two different heel heights and of hormonal oscillation throughout different phases of the menstrual cycle on spinopelvic alignment. Notably, 70 females with an average age of 20.42 ± 1.51 years participated in this study, wearing each female two different heel heights as follows: low (2.5 cm) and high (7 cm). Spinopelvic alignment was evaluated by rasterstereography formetric 3D analysis during early follicular, ovulatory, and mid-luteal phases of the menstrual cycle. Statistical analysis showed that there was no significant difference (p > 0.05) on spinopelvic alignment [kyphotic angle (KA), trunk inclination (TI), and pelvic inclination] between wearing low- or high-heeled shoes during early follicular, ovulatory, and mid-luteal phases of the menstrual cycle. Considering that high-heeled shoes are traditionally associated with femininity, body image, beauty, and charm, this research has important biopsychosocial implications that should be explored in detail in future studies.

Control Strategies for Gait Tele-Rehabilitation System Based on Parallel Robotics

Among end-effector robots for lower limb rehabilitation, systems based on Stewart–Gough platforms enable independent movement of each foot in six degrees of freedom. Nevertheless, control strategies described in recent literature have not been able to fully explore the potential of such a mechatronic system. In this work, we propose two novel approaches for controlling a gait simulator based on Stewart–Gough platforms. The first strategy provides the therapist direct control of each platform using movement data measured by wearable sensors. The following scheme is designed to improve the level of engagement of the patient by enabling a limited degree of control based on trunk inclination. Both strategies are designed to facilitate future studies in tele-rehabilitation settings. Experimental results have illustrated the feasibility of both control interfaces, either in terms of system performance or user subjective evaluation. Technical capacity to deploy in tele-rehabilitation was also verified in this work.

EFFECTS OF SCHROTH EXERCISE ON COBB’S ANGLE, VITAL CAPACITY AND THE IMPROVEMENT OF DAILY ACTIVITIES ON PATIENTS WITH ADOLESCENT IDIOPATHIC SCOLIOSIS

The aim of this study was to investigate the effects of Schroth exercise on Cobb's angle, vital capacity as well as the improvement of daily activities on patients with idiopathic adolescent scoliosis. Forty patients with idiopathic scoliosis with a Cobb thoracic vertebral angle of 15-30 degrees or higher and the Risser sign stage 3 or higher. The Schroth exercise was applied 3 times a week for 12 weeks. We measured the chest trunk inclination, Cobb angle and vital capacity before and after exercise program. A comprehensive search for all published review articles for spinal deformity was undertaken on PubMed, PEDRO, Google Scholar, Physiopedia up to December 2018. All full-text articles reporting evaluation, validation, surgical, orthotic, and/or physiotherapeutic scoliosis specific exercises (PSSE) treatment outcomes of these spinal deformities were retrieved and analyzed by us and methodology for functional assessment of patients with AIS was developed. Forty patients with idiopathic scoliosis with a Cobb thoracic vertebral angle of 15-30 degrees or higher and the Risser sign stage 3 or higher. The Schroth exercise was applied 3 times a week for 12 weeks. We measured the chest trunk inclination, Cobb angle and vital capacity before and after exercise program. For a period of 12 weeks we accessed adolescents with AIS. All adolescents make Schroth PSSE. The analysis of the results confirms the positive effect of the PSSE to improve muscle endurance, balance and correction of the scoliosis. Within a month from the beginning, patients reported no back pain and within 2 months – a respiratory improvement, an enlargement of the chest, a reduced Cobb angle, an increased vital capacity. PSSE seem to have positive effects by reducing the symptoms and improving functions and body asymmetries. Schroth method is effective of preventing the scoliosis’ progression. The conservative method of treating scoliosis was found to be effective even at a Cobb angle of 35 degrees or higher. In the future, universal methods of approaching exercises and preventive training for the treatment of scoliosis needs to be further developed.

The relationship between the position of the spine in the sagittal plane and longitudinal arching of the feet in school-age girls and boys - cross-sectional study.

Introduction: Discoveries concerning the role of connective tissue and myofascial chains require a change in thinking about the functioning of the human body and verification of the approach to correcting posture defects. The aim of the study was to evaluate the relationship between the shape of the spine in the sagittal plane and longitudinal arching of the feet. Material and methods: 271 girls and 241 boys aged 10-12 years were examined. Height and body weight were measured. The BMI was calculated and the status of body weight was estimated. The depth of thoracic kyphosis and lumbar lordosis as well as the sagittal trunk inclination were assessed using the Zebris Pointer ultrasound system. Arching of the feet was determined on the basis of the Arch Index on BTS P-walk platform. Statistica v13 software was used to analyse the data. Results: Both sexes showed a tendency to have deeper thoracic kyphosis and lumbar lordosis. About 15% of the participants had flatfeet. Hollow and correct arching of the feet was observed with a similar frequency (38-43%). Hollow feet arching was accompanied by shallower lumbar lordosis and a shift of the body's general centre of gravity backwards. The participants with flat foot arching tend to have deeper lumbar lordosis. A greater depth of physiological curvatures of the spine and lower longitudinal arching of the feet were observed in boys. BMI was positively correlated with decreased arching of the feet and deepened lumbar lordosis. Conclusions: Longitudinal arching of the feet significantly correlates with the depth of lumbar lordosis and trunk balance.

Changes of static and dynamic spine alignment in patients with severe haemophilia.

Haemophilic arthropathy results in a restricted range of motion and pain that often affects gait. The effect of these gait changes on spinal posture has not been studied. To evaluate whether the altered joint situation in patients with haemophilia (PwH) leads to compensatory mechanisms evident in the trunk and spine, considering static and dynamic conditions. PwH and healthy controls (20-65 years) were examined using rasterstereography in a controlled cohort study. Analysis was performed in static and dynamic conditions in regard to gait phases. Joint status was determined using the Haemophilia Joint Health Score (HJHS). Static measurements showed no group differences in PwH (n = 40) compared to healthy controls (n = 40) except pelvic torsion (median [25%-quartile;75%-quartile]: -1.9[-3.2;.9]° vs. .5[-1.1;1.9]°; P = .007). In contrast, under dynamic conditions PwH showed significantly higher trunk inclination and lower apex lumbar lordosis in all gait phases. Additionally, pelvic torsion was increased in mid stance and terminal swing. Considering joint status, PwH had a higher global HJHS (23.5[13.0;30.0] vs. 3.0[1.0;5.0]; P<.001). A significant moderate correlation was shown between the HJHS mobility score and spine parameters (r = .228-.588; P<.05). Degenerative joint changes in PwH lead to altered spine posture during gait. A reason could be the reduced mobility in the affected joint. Changes in spinal and pelvic posture lead to higher structural burdens; therefore, clinicians should focus on posture of spinal column during gait in daily treatment.

Machine Learning to Improve Orientation Estimation in Sports Situations Challenging for Inertial Sensor Use.

In sports, inertial measurement units are often used to measure the orientation of human body segments. A Madgwick (MW) filter can be used to obtain accurate inertial measurement unit (IMU) orientation estimates. This filter combines two different orientation estimates by applying a correction of the (1) gyroscope-based estimate in the direction of the (2) earth frame-based estimate. However, in sports situations that are characterized by relatively large linear accelerations and/or close magnetic sources, such as wheelchair sports, obtaining accurate IMU orientation estimates is challenging. In these situations, applying the MW filter in the regular way, i.e., with the same magnitude of correction at all time frames, may lead to estimation errors. Therefore, in this study, the MW filter was extended with machine learning to distinguish instances in which a small correction magnitude is beneficial from instances in which a large correction magnitude is beneficial, to eventually arrive at accurate body segment orientations in IMU-challenging sports situations. A machine learning algorithm was trained to make this distinction based on raw IMU data. Experiments on wheelchair sports were performed to assess the validity of the extended MW filter, and to compare the extended MW filter with the original MW filter based on comparisons with a motion capture-based reference system. Results indicate that the extended MW filter performs better than the original MW filter in assessing instantaneous trunk inclination (7.6 vs. 11.7° root-mean-squared error, RMSE), especially during the dynamic, IMU-challenging situations with moving athlete and wheelchair. Improvements of up to 45% RMSE were obtained for the extended MW filter compared with the original MW filter. To conclude, the machine learning-based extended MW filter has an acceptable accuracy and performs better than the original MW filter for the assessment of body segment orientation in IMU-challenging sports situations.

Trunk Inclination During Squatting is a Better Predictor of the Knee-Extensor Moment Than Shank Inclination.

A limitation of previous studies on squatting mechanics is that the influence of trunk and shank inclination on the knee-extensor moment (KEM) has been studied in isolation. The purpose of the current study was to determine the influence of segment orientation on the KEM during freestanding barbell squatting. Repeated-measures cross sectional. University research laboratory. Sixteen healthy individuals (8 males and 8 females). Each participant performed 8 squat conditions in which shank and trunk inclinations were manipulated. 3D kinematic and kinetic data were collected at 250 and 1500Hz, respectively. Regression analysis was conducted to identify the individual relationships between the KEM and the trunk and shank inclination at 60° and 90° of knee flexion. To identify the best predictor(s) of the KEM, stepwise regression was implemented. Increased shank inclination increased the KEM (P < .001, R2 = .21-.25). Conversely, increased trunk inclination decreased the KEM (P < .001, R2 = .49-.50). For the stepwise regression, trunk inclination entered first and explained the greatest variance in the KEM (all P < .001, R2 = .49-.50). Shank inclination entered second (all P < .010, R2 = .53-.54) and explained an additional 3% to 5% of the variance. Our results confirm that inclination of the trunk and shank have an opposing relationship with the KEM. Increased forward shank posture increases the KEM, while increased forward trunk posture decreases the KEM. However, when viewed in combination, the trunk was the superior predictor of the KEM, highlighting the fact that increased quadriceps demand created by a forward shank can be offset by trunk inclination.

The Effect of Blended Learning New Technologies and Direct Video Feedback on the Long Jump Technique in Primary School Students

ABSTRACT In this study, three different methods of teaching the long jump were evaluated. One hundred and thirty-one students of fifth and sixth grade (Mage = 11.4 ± 0.47 years) were randomly assigned into three groups. The first intervention group (INT) followed a blended learning approach using interactive learning activity software, the second intervention group (INTVF) followed the same method with an added direct video feedback system and the control group (CON) was taught the traditional approach. A pre-post 2D kinematic analysis of the students’ body segments’ position was conducted. Α two-way mixed ANOVA analysis showed an improvement in all three groups. However, the INTVF group performed significantly better regarding leg joints angles, trunk inclination, and body mass center parameters at take-off, compared to the INT and CON groups. In conclusion, teaching using blended learning, new technologies and direct video feedback seems to support students in developing a more efficient take-off technique in long jump.

High Thoracic Kyphosis and Backward Trunk Inclination Angles in the Single-Leg Standing Position Associate With Medial Elbow Injuries in Youth Baseball Players: A Cross-Sectional Study.

Baseball pitching is a coordinated movement involving the spine. A previous study indicated that increased thoracic kyphosis angle in a standing position was a risk factor for medial elbow injuries in youth baseball players. However, spinal alignments in single-leg standing and their relationships with medial elbow injuries, scapular alignment, or hip joint range of motion are unclear. To examine the difference in spinal alignment between standing and single-leg standing positions in youth baseball players and analyze their relationship with elbow injuries, scapular alignment, or hip joint range of motion. Cross-sectional study. University laboratory. There were 51 youth baseball players with medial epicondylar fragmentation (medial elbow injury group) and 102 healthy youth baseball players (control group). Thoracic kyphosis, lumbar lordosis, and trunk inclination angles during standing and single-leg standing, forward scapular posture, and hip joint range of motion. In the single-leg standing position, the thoracic kyphosis and backward trunk inclination angles were significantly higher in the medial elbow injury group than in the control group (P = .016 and P = .046, respectively). In the standing position, no significant difference was observed between both groups. The thoracic kyphosis angle in single-leg standing was positively correlated with the bilateral forward scapular posture in the medial elbow injury (P = .008 and P < .001 on the throwing and nonthrowing sides, respectively) and control (P = .010 and P = .032 on the throwing and nonthrowing sides, respectively) groups. High thoracic kyphosis and backward trunk inclination angles are characteristics during single-leg standing in youth baseball players with medial elbow injuries. Spinal alignment measurement in single-leg standing may be useful for identifying youth baseball players who are at risk for sustaining medial elbow injury.