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Kicking is fundamental in many field-based sports. Most studies investigating kicking performance have been conducted with male athletes, resulting in a dearth of specific data to inform coaching of this skill in female players. This systematic review aimed to compare kicking biomechanics in male and female athletes in field-based sports. As per PRISMA guidelines, articles were retrieved from searches across five online databases. Studies investigating kicking biomechanics in field-based athletes of both sexes were eligible for inclusion. Articles were screened using Covidence and data extracted based on STROBE recommendations. The review included 23 studies, featuring 455 soccer players. Male athletes produced significantly greater ball velocities and linear velocities of the ankle, foot, and toe than females. Males had greater ankle plantarflexion angles than females at ball strike, while females used larger trunk flexion ranges than males. Hip and knee torques and ball-to-foot velocity ratios were greater in men than women. Skilled players generated power using tension arcs; a technique not seen in novices. Skill level within sex may have a greater influence on kicking performance than differences between the sexes. This review highlights the need for further research investigating kicking performance in both sexes across the spectrum of sports.

Workers exposed to repeated trunk flexions are at risk of onset of low-back disorders and in individuals aged over 50 this issue is exacerbated by the physiologic decline of the musculoskeletal system and longer lifetime occupational exposure. In this study, we investigated the existence of possible age-related differences in patterns of trunk flexion of workers in the metalworking industry. Thirty-three subjects were monitored during an actual shift using a wearable Inertial Measurement Unit (IMU) to assess trunk flexion angles (i.e. between 30° and 60°, 60°-90° and > 90°). Results show that older workers spent less time with their trunk flexed, regardless of the class of flexion considered, with respect to their younger colleagues. Although further studies are necessary to clarify the existence of strategies aimed at optimising trunk movements during ageing, the IMU-based approach appears useful in highlighting potentially harmful conditions, especially in workers with marked signs of decline in their physical capacities. Practitioner summary: Wearable sensors, which are well tolerated and minimally intrusive, represent a valid option to continuously monitor trunk posture in workers employed in metalworking industry. The results of this study show that they provide valuable information about the patterns of flexion of young and old individuals engaged in physically demanding tasks.

Objective: In 2020, coronavirus disease-2019 (COVID-19) became the cause of a pandemic. In response, the Japan Sports Agency issued warnings about secondary damage to health, such as the threat to physical and mental well-being due to the lack of exercise in this situation. In this study, we report on cross-sectional and longitudinal examinations of standing trunk flexion to evaluate how temporary long-term school closures affected musculoskeletal function in elementary school students. Patients and Methods: All children in one public elementary school in T-city during the school years 2019 and 2020 were included in this study. A digital forward flexion meter was used to measure standing trunk flexion. Results: In this study, 284 (284/289: 98.3%) and 266 (266/274: 97.1%) children in school years 2020 and 2019, respectively, were found to have valid data for cross-sectional analysis. The standing trunk flexion did not show significant differences between grades or sexes. In the longitudinal analysis, the results of the comparison of standing trunk flexion in children for two consecutive years revealed significant differences only between grades 3 and 4 (P

The lumbar region offers various muscle recruitment strategies to achieve a task goal under varying conditions. For instance, trunk movement control can be reorganized under the influence of low back pain. How such task-modulation is obtained is not fully understood. The objective of this study was to characterize superficial lumbar muscle recruitment strategies under the influence of delayed-onset muscle soreness (DOMS) during unexpected trunk perturbations. Healthy participants experienced a series of 15 sudden external perturbations with and without the influence of low back DOMS. During these perturbations, high-density surface electromyography was used to characterize recruitment strategies of superficial lumbar muscles, while kinematics sensors were used to characterize movements of the trunk. Lumbar muscle recruitment strategies, characterized by the amplitude of muscle activity amplitude, the latencies of the reflex activity and the spatial distribution of muscle activity, were compared across perturbations trials and with and without DOMS. An attenuation of lumbar muscle activity amplitude was observed across perturbation trials without DOMS, but not with DOMS. The spatial distribution of muscle activity was similar with and without DOMS. No significant changes in reflex activity latency and trunk flexion movement were observed. Following an unexpected trunk perturbation under DOMS effects, trunk movement are controlled using two different superficial lumbar muscles control strategies: keeping a constant level of their overall muscle activity and using a variable muscle recruitment pattern.

Introduction Marines must complete an intensive Assessment and Selection (A&S) course before becoming a U.S. Marine Forces Special Operations Command (MARSOC) Raider. Following selection, marines are given training recommendations designed to maintain performance characteristics deemed relevant to successfully complete a rigorous 9-month Individualized Training Course (ITC). However, training strategies are individually implemented by the marine, and the time between the two courses is highly irregular, ranging between 2 months and 24 months based on operational factors related to military occupational specialty (MOS). The purpose of this study was to evaluate changes in performance between the completion of A&S and the start of ITC and to examine if the duration between courses and previous MOS influenced changes in performance. Materials and Methods Body fat percentage (BF%), anaerobic power (AP), anaerobic capacity (AC), aerobic capacity (VO2max), knee flexion (KF), knee extension (KE), trunk extension (TE), and trunk flexion (TF) isokinetic strength were collected on 38 marines (age: 25.1 ± 2.7 years, height: 1.77 ± 0.05 m, mass: 83.2 ± 7.7 kg, Post-A&S to ITC start: 204.1 ± 68.4 days) following A&S and directly before ITC. Results Pre-ITC students had significantly greater mass (P = .002), BF% (P = .000), and AP (P = .039). There were no significant changes in AC (P = .170), VO2max (P = .259), KF (P = .400), KE (P = .320), TE (P = .178), and TF (P = .643). There was no significant relationship between performance outcomes and time between courses and previous MOS. Conclusion Current training strategies appear effective at addressing performance deficits that occur as a result of A&S, while maintaining high levels of KF, KE, TE, TF, AC, and VO2max. However, pre-ITC students still exhibited AP deficits compared to active marine raiders, so forthcoming programming may benefit from an increased emphasis on AP. Assessment of additional selectees at these timepoints, as well as students before A&S may provide valuable information to MARSOC human performance specialists to develop programing, ultimately leading to a higher ITC graduation rate, increased force readiness, and decreased financial burden forcewide.

Background The head, arms and trunk segment constitute a large proportion of the body’s mass. Therefore, small alterations in trunk inclination may affect lower limb joint moments and muscle activation patterns. Although previous research has investigated the effect of changing frontal plane inclination of the trunk, it is not clear how increasing trunk flexion will impact on the activation of the lower limb muscles. Research question What is the effect of independently manipulating trunk flexion angle on lower limb kinematics, moments and muscle function? Methods Gait analysis was carried out on 20 healthy people under four trunk flexion conditions: normal walking (NW), NW-5°, NW+5° and NW+10°. For the latter three conditions, a biofeedback approach was used to tightly control trunk flexion angle. A linear mixed model was used to investigate the effect of changing trunk flexion on joint angles, moments, and knee muscle activation. Results There were clear increases in hip and ankle moments as trunk flexion was increased, but no change in knee moments. The results also showed a linear increase in knee flexor muscle activity and a corresponding increase in co-contraction as trunk flexion increased. Interestingly, there was a dramatic change in the profile of hamstring activity. In the medial hamstrings, this change led to a 100% increase in activation during early stance as flexion was increased by 5° from NW. Significance This is the first study to demonstrate a strong dependence of knee flexor muscle activity on trunk flexion. This is important as people with knee osteoarthritis have been observed to walk with elevated muscle activation and this has been linked to increased joint loads. It is possible that these altered muscle patterns may result from increased trunk flexion during walking.

[Purpose] The purpose of this study was to develop a simpler method to estimate the intervertebral disc compressive force in healthy older adults. We also examined the validity of a simpler estimation formula for patients with spinal diseases. [Participants and Methods] Fifty-two older adults participated in the study. The standing posture was measured using a three-dimensional motion capture system. The intervertebral disc compressive force was calculated using a previously reported method. Correlation analysis was used to detect the relationship between the measured parameters and the intervertebral disc compressive force. Multiple regression analysis was performed to obtain an equation for the intervertebral disc compressive force. Correlation analysis was used to determine the regression equation for the patients with spinal diseases. [Results] Multiple regression analysis showed that trunk flexion/extension angle and body mass were significantly associated with intervertebral disc compressive force. A correlation was found between the measured and predicted values in the healthy older adults, whereas both values were inconsistent in patients with spinal diseases. [Conclusion] The results of our study demonstrated that the trunk flexion/extension angle and body mass are indicators of intervertebral disc compressive force and can be used to assess low back mechanical stress in healthy older adults.

García-Vaquero, MP, Ruiz-Pérez, I, Barbado, D, and Vera-Garcia, FJ. Electromyographic and kinematic analysis of the flexion-rotation trunk test. J Strength Cond Res 34(12): 3386-3394, 2020-Although most trunk endurance field protocols are performed in the sagittal or frontal planes, the flexion-rotation trunk (FRT) test combines trunk flexion with rotation, which may be relevant to rotation-related sports. The aim of this study was to describe the trunk and hip muscle activation and fatigue and the range of hip flexion of this test. Twenty-seven physically active males and females performed the FRT test after a period of practice. Electromyographic (EMG) signals were bilaterally collected from the rectus abdominis (RA), internal oblique (IO), and rectus femoris (RF), and hip flexion amplitude was measured using a biaxial electrogoniometer. Because the fast Fourier transform algorithm requires stationary EMG signals, subjects performed a 6-second isometric trunk flexion-rotation repetition just before and just after the test execution (preexecution and postexecution repetitions, respectively). Rectus abdominis showed the highest mean activation levels (approximately 30% maximal voluntary isometric contractions [MVC]) in the preexecution repetition, followed by IO (approximately 20% MVC). Also, the mean power frequency (MPF) significantly decreased from the pre-execution to the postexecution repetition for RA and IO, which shows abdominal muscle fatigue. Although each trunk flexion-rotation repetition involved an average 8-14° hip flexion, the RF activation was lower than 10% MVC, and no significant MPF reduction (i.e., no muscle fatigue) was observed for this muscle. In addition, significant negative correlations were found between the FRT test scores and the normalized EMG amplitudes of RF. Based on these results, the FRT test seems a valid field protocol to assess abdominal muscle endurance in trunk flexion-rotation exertions.

Objective Work-related musculoskeletal disorders (MSDs) are common in the dental hygiene profession. Awkward postures contribute to MSDs and magnification loupes have been suggested to reduce this risk factor and minimize MSDs. Methods After IRB approval, 24 hygienists were enrolled in the study: twelve hygienists wearing loupes with a standard manufacturer determined declination angle (control) and 12 hygienists wearing loupes with a custom measured declination angle (experimental). To measure changes in neck and trunk flexion, accelerometers were placed on the occipital region of head, cervical vertebrae C5, and thoracic vertebrae T5 and baseline posture was recorded. Typodonts with artificial calculus simulated the oral environment. Participants were randomly assigned to wear their designated loupes during the first or second trial of the experiment and scaled in each quadrant (UR, LR, UL, LL) of the mouth for two minutes. Participants completed the scaling task twice: in the loupes and no loupes condition in a counterbalanced order. Three-way mixed design ANOVA was used to determine posture differences in neck and trunk posture. Results Those wearing custom loupes (M = 16.52, SD = 6.40) had significantly less trunk flexion while scaling compared to hygienists wearing standard loupes (M = 22.27, SD = 6.40), F(1, 22) = 7.14, P = .01. Neck flexion was not significantly affected while scaling between loupes vs no loupes or loupes type condition, (P's > .05). Conclusion Posture was partially impacted by loupes type. Custom loupes resulted in less trunk flexion. Neck flexion was not affected by either loupes type.

O objetivo deste estudo foi investigar a existência de associação entre a Movimentação Manual de Cargas (MMC) e lombalgia ocupacional em carregadores da Central de Abastecimento de Sergipe (CEASA/SE). Para tanto, um estudo observacional analítico foi conduzido com 60 carregadores. As variáveis investigadas foram coletadas mediante formulário estruturado e instrumentos de medição específicos. Os dados foram tratados estatisticamente e o nível de significância fixado em p

Objective A computer vision method was developed for estimating the trunk flexion angle, angular speed, and angular acceleration by extracting simple features from the moving image during lifting. Background Trunk kinematics is an important risk factor for lower back pain, but is often difficult to measure by practitioners for lifting risk assessments. Methods Mannequins representing a wide range of hand locations for different lifting postures were systematically generated using the University of Michigan 3DSSPP software. A bounding box was drawn tightly around each mannequin and regression models estimated trunk angles. The estimates were validated against human posture data for 216 lifts collected using a laboratory-grade motion capture system and synchronized video recordings. Trunk kinematics, based on bounding box dimensions drawn around the subjects in the video recordings of the lifts, were modeled for consecutive video frames. Results The mean absolute difference between predicted and motion capture measured trunk angles was 14.7°, and there was a significant linear relationship between predicted and measured trunk angles ( R2 = .80, p < .001). The training error for the kinematics model was 2.3°. Conclusion Using simple computer vision-extracted features, the bounding box method indirectly estimated trunk angle and associated kinematics, albeit with limited precision. Application This computer vision method may be implemented on handheld devices such as smartphones to facilitate automatic lifting risk assessments in the workplace.

With the lack of pitch count regulation, youth softball pitchers are experiencing unremitting high stresses on the anterior shoulder. The purpose of this study was to examine the association of acute changes in the long head of the biceps tendon with pitching kinematics and kinetics in youth softball pitchers following an acute bout of pitching. Twenty-three softball pitchers (12.17±1.50 yrs.; 160.32±9.41 cm; 60.40±15.97 kg) participated. To investigate the association between biceps tendon changes and kinematic and kinetic changes from pre- to post-simulated game, each biceps tendon measure was split into those whose biceps tendon thickness, width, and/or area increased pre- to post-simulated game, and those whose did not. There were significant differences in biceps tendon longitudinal thickness (Z=− 2.739, p=0.006) and pitch speed; as well as a difference between groups in biceps tendon transverse thickness and the amount of change in trunk rotation at the start of the pitching motion (p=0.017) and the amount of change in trunk flexion at ball release (p=0.030). This study illustrates the association of trunk and lower extremity kinematics and shoulder kinetics with morphologic changes in the biceps tendon with an acute bout of windmill softball pitching.

Background Abdominal draw-in maneuver (ADIM) has been recommended to achieve appropriate trunk muscle response for patients with non-specific chronic low back pain (CLBP). However, it has remained unclear whether the intervention with ADIM could change the trunk muscle response to sudden release from loading, which is considered to contribute mechanical circumstances to low back pain. The purpose of the present study was to investigate the effects of the intervention with ADIM on electromyography (EMG) activities of trunk muscles following sudden release from loading. Methods Seventeen subjects with non-specific CLBP participated. Subjects resisted trunk flexion or extension loading in semi-seated position, and then the loading was suddenly released. EMG recordings of 6 trunk muscles were acquired using a wireless surface EMG system. Onset and offset times were calculated from the EMG data. The intervention with ADIM was provided for 4 weeks. The onset and offset times were compared between pre- and post-intervention with ADIM. Results At the post-intervention, the onset of trunk flexors following release from trunk flexion loading became significantly earlier than pre-intervention (P = 0.028). The offset of flexors following release from trunk extension loading of post-intervention was significantly earlier than that of pre-intervention (P = 0.001). Conclusions We showed that the intervention with ADIM changed the EMG activity of trunk flexors in response to sudden release from loading. These results suggest a possibility that ADIM might be effective to improve the neuromuscular control of trunk flexors for the treatment of young patients with non-specific CLBP.

Background: The chronic low back pain (LBP) had been considered an important occupational disorder with several strategy available to treatment, however, few studies had been evaluated the treatment combination. Objectives: The aim of present study was compared the effects of combination of crocheting associated to Kinesiotherapy treatment and Kinesiotherapy isolated treatment on function of lumbar spine and pain during achievement of daily life in patients with chronic LBP. Methods: Forty subjects were distributed randomly in two groups: Crochetagem + Kinesioterapy (C; n: 18; 47.5 ± 7.75 years) and Kinesiotherapy (K, n: 18; 45.3 ± 8.93 years). The C group was treated by crocheting technique associated with kinesiotherapy using therapeutic ball. The K group performed a kinesiotherapy treatment using just a therapeutic ball. The following parameters were evaluated: abdominal strength, articular range motion and the data of Rolland Morris and Oswestry Disability Index questionnaires were evaluated before and after 8 weeks of treatment. Both groups performed all therapeutic sessions for 50 minutes, three times a week. Results: Significant differences (p

BACKGROUND Patients with Parkinson's disease (PD) and associated lateral trunk flexion (LTF) cannot accurately perceive their own verticality. OBJECTIVE We measured the subjective postural vertical in coronal plane (SPVc) angle on patients' ipsilateral and contralateral sides and combined to clarify the effects of SPVc on LTF. We also investigated effects of the SPVc angle on LTF severity. METHODS Thirty-nine patients (aged 74.1 ± 7.6 years) were divided between those with mild LTF (LTF angle

Objective: Many caregivers often carry infants using baby carriers until they are approximately 36 months old. The purpose of this study was to...

BACKGROUND The use of tablet during the office work is on the rise, but the biomechanical response of tablet use under various sitting postures is not well understood. OBJECTIVE This study quantitatively measured changes in trunk kinematics under three sitting conditions (raised leg, neutral leg, and lowered leg) while using a tablet. METHODS Fifteen participants were asked to sit on a chair with three different postures while staring at a handheld tablet or gazing straight ahead with a bare hand, and the head flexion, lumbar flexion and trunk inclination were captured with electrical goniometers. RESULTS The results revealed significantly less lumbar flexion (12.8%) and trunk inclination (28.0%) while using the tablet compared to the empty hand condition (p

The purpose of this pilot case study is to investigate the effects of Pi-lates training on hamstring/quadriceps ratio, trunk strength, shoulder strength, and body composition in adolescent baseball players. Eight adolescent baseball players, 15 years of age, participated in Pilates program (supervised training, 50 min per session for three times a week for 8 weeks) using reformer and Cadillac. The intensity of the program was progressively increased by applying beginner level for 1–2 weeks, intermediate level for 3–6 weeks, and advance level for 7–8 weeks. To verify the effect of the Pilates program on hamstring/quadriceps ratio, trunk strength, shoulder strength and body composition, participants performed bioelectrical impedance analysis and isokinetic testing at pre- and posttraining. After the Pilates training, there were significant increases in body weight (P

[Purpose] To compare flexion and extension peak torque of patients with nonspecific-chronic low back pain who were classified as directional preference subgroups, and their matched healthy controls. [Participants and Methods] Fifty male volunteers (25 with non-specific chronic low back pain and 25 healthy-matched controls) consented to participate. The investigator collected all demographic data, hips, knees and spinal mobility in addition to the peak torque using the Biodex isokinetic dynamometer. The measurement protocol consisted of 2 sets of 10 consecutive flexion-extension efforts performed at 120°/sec and 60°/sec angular velocity. A two minutes rest period was given between sets. The preset 50° range of motion included 20°(+20°) of trunk extension and 30°(-30°) of trunk flexion. [Results] A 2 × 2 mixed-design ANOVA showed a significant group X isokinetic velocity interaction. The main effect of isokinetic velocity was also significant. In reference to the peak torque of the flexors of the trunk, the main effect of group was significant. [Conclusion] The extension peak torque significantly depends on the velocity of the isokinetic dynamometer; however the flexion peak torque significantly depends on the participants' group attribution.

Hamstring shortness and postural deformities are frequent in adolescents. For this reason, the purpose of this study was to analyse the influence of a short-term stretching program in hamstring extensibility and sagittal spinal curvatures in high school students. Sixty-two male high school students aged 14-17 years old performed a 70 seconds hamstring stretching program (3 exercises) twice a week for five weeks during their physical education classes. Hamstring extensibility was measured by the straight leg raise test and sit-and-reach test. Thoracic and lumbar curves and pelvic inclination were measures in relaxed standing and in the sit-and-reach test. These measures were assessed before (pre-test) and after (post-test) the intervention program. Significant increases in the sit-and-reach score (d= 0.23) and in the straight leg raise angle (d= 0.85-0.90) were found. Sagittal spinal curvatures in standing showed no differences between pre- and post-test. In the maximal trunk flexion position during the sit-and-reach was detected a lower thoracic kyphosis and posterior pelvic tilt (p < 0.05) in post-test although with a low size effect (d=0.02-0.22). A hamstring muscle stretching program with a volume of 2 sessions per week (70 seconds each session), for 5 weeks, improves hamstring extensibility in adolescents and slightly reduces the thoracic bending and posterior pelvic tilt in trunk flexion postures with extended knees Debido a la frecuencia de casos con una reducida extensibilidad isquiosural y alteraciones posturales en adolescentes, el objetivo de este estudio fue analizar la influencia de un programa de estiramientos, de corta duración, en la extensibilidad isquiosural y disposición sagital del raquis en estudiantes de Educación Secundaria. A sesenta y dos adolescentes varones (14-17 años) se les midió la extensibilidad isquiosural (test sit-and-reachy test de elevación de la pierna recta) antes (pre-test) y después (post-test) de un programa escolar de 5 semanas (2 sesiones semanales), compuesto por tres estiramientos de la musculatura isquiosural, con una duración total por sesión de 70 segundos. También se valoró la disposición sagital del raquis torácico, lumbar e inclinación pélvica en bipedestación relajada y en el sit-and-reach. Se encontró un aumento significativo en la distancia alcanzada en el test sit-and-reach (d= 0,23) y en el ángulo de flexión co-xofemoral en el test de elevación de la pierna recta (d= 0,85-0,90). La disposición sagital del raquis en bipedesta-ción no mostró diferencias entre el pre- y post-test. En la posición de máxima flexión del sit-and-reach, hubo una menor cifosis torácica y menor retroversión pélvica (p < 0,05) en el post-test, aunque con un tamaño del efecto bajo (d=0,02-0,22). Un programa de estiramientos de la musculatura isquiosural realizado en las dos clases semanales de Educación Física (70 segundos de estiramiento en cada clase), durante 5 semanas, mejora la extensibilidad isquiosural de adolescentes y reduce, ligeramente, la flexión torácica y la retroversión pélvica en la posición de máxima flexión del tronco con rodillas extendida Actividad Física y Deporte

Objective: To observe the efficacy of bilateral subthalamic nucleus deep brain stimulation on Pisa syndrome in patients with Parkinson's disease.Methods: A total of 52 patients with Parkinson's disease who underwent deep brain stimulation in Beijing Hospital from July 1, 2016 to July 1, 2020 were reviewed. The clinical data were collected for the patients who met the diagnostic criteria of Pisa syndrome on “Medication-Off” state pre-operatively.Results: Two patients met the diagnostic criteria of Pisa syndrome before operation, with a Pisa angle of 10 and 14°, respectively. The lateral trunk flexion of the two patients improved after operation. In stimulation-on/medication-off state, the Pisa angle decreased from 10 to 2° and from 14 to 6°, respectively.Conclusion: Bilateral subthalamic nucleus deep brain stimulation might have beneficial effects on lateral trunk flexion in PD patients, but the predictors of curative effect are not clear.

Introduction: Elite youth soccer players suffer increasing numbers of injuries owing to constantly increasing physical demands. Deficits in neuromuscular performance may increase the risk of injury. Injury risk factors need to be identified and practical cut-off scores defined. Therefore, the purpose of the study was to assess neuromuscular performance parameters within a laboratory-based injury risk screening, to investigate their association with the risk of non-contact lower extremity injuries in elite youth soccer players, and to provide practice-relevant cut-off scores.Methods: Sixty-two elite youth soccer players (age: 17.2 ± 1.1 years) performed unilateral postural control exercises in different conditions, isokinetic tests of concentric and eccentric knee extension and knee flexion (60°/s), isometric tests of hip adduction and abduction, and isometric tests of trunk flexion, extension, lateral flexion and transversal rotation during the preseason period. Non-contact lower extremities injuries were documented throughout 10 months. Risk profiling was assessed using a multivariate approach utilizing a Decision Tree model [Classification and Regression Tree (CART) method].Results: Twenty-five non-contact injuries were registered. The Decision Tree model selected the COP sway, the peak torque for knee flexion concentric, the functional knee ratio and the path of the platform in that hierarchical order as important neuromuscular performance parameters to discriminate between injured and non-injured players. The classification showed a sensitivity of 0.73 and a specificity of 0.91. The relative risk was calculated at 4.2, meaning that the risk of suffering an injury is four times greater for a player, who has been classified as injured by the Decision Tree model.Conclusion: Measuring static postural control, postural control under unstable condition and the strength of the thigh seem to enable a good indication of injury risk in elite youth soccer players. However, this finding has to be taken with caution due to a small number of injury cases. Nonetheless, these preliminary results may have practical implications for future directions in injury risk screening and in planning and developing customized training programs to counteract intrinsic injury risk factors in elite youth soccer players.

The paper compares three assessment methods for the measurement of the trunk range of motion (ROM) in flexion-extension movements of subjects suspected of lumbar vertebrae instability (LVI). For five male adults affected by low-back pain and with morpho-dynamic prescription for suspected LVI, ROM was computed: from the analysis of morpho-dynamic radiographs, according to the definition proposed by i) Kapandji and ii) Yang et al.; from the analysis of the flexion-extension movement captured with an optoelectronic acquisition system iii) as the maximum angular stroke in transductors’ displacement, according to a specifically designed custom protocol. Data obtained from optoelectronic acquisitions result comparable with literature values, suggesting the suitability of optoelectronic systems as non-invasive measurement tool for the trunk ROM assessing, to support the physician in the LVI diagnosis.

We conducted a retrospective study to test our hypothesis that the subjective postural vertical (SPV) ratio, i.e., SPV in relation to the lateral flexion axis, is predictive of lateral trunk flexion (LTF) in patients with Parkinson's disease (PD). The study group comprised 25 patients with PD. The SPV angle, i.e., the subjective perception of a vertical position with reference to the vertical axis, and the SPV ratio, i.e., the SPV angle with reference to the axis of lateral flexion, were calculated. The SPV ratio (r = 0.698 p = 0.001) and LTF angle (r = −0.601 p = 0.001) were found to correlate with change in the LTF angle calculated at 1 year. The SPV ratio was significantly smaller in the LTF angle-improved group (n = 12) than in the non-improved group (n = 13) (0.99 ± 0.78 vs 1.66 ± 0.71, p = 0.011). The AUC under the ROC curve of the SPV ratio for discrimination of LTF improvement was 0.795 (95% confidence interval: 0.61–0.98). Our study showed that the SPV ratio is associated with change in the LTF and that the SPV ratio can conceivably be used to predict the likelihood of improvement in patients’ LTF.

BACKGROUND: Although trunk muscles are involved in many important functions, evaluating trunk muscle strength is not an easy task. If trunk muscle mass and thickness could be used as indicators of trunk muscle strength, the burden of measurement would be reduced, but the relationship between trunk muscle strength and trunk muscle mass and thickness has not been clarified. OBJECTIVE: The purpose of this study was to clarify the relationship between trunk muscle strength and trunk muscle mass by bioelectrical impedance analysis and trunk muscle thickness by ultrasound imaging in healthy adults. METHODS: One hundred and twenty-one healthy university students were included in this study. Trunk flexion/extension muscle strength and trunk muscle mass by bioelectrical impedance analysis, and trunk muscle thickness by ultrasound imaging were measured. RESULTS: Both trunk flexion strength and trunk extension strength were significantly correlated with trunk muscle mass and oblique and rectus abdominis muscle thickness. Multiple regression analysis showed that trunk extension muscle strength had an independent relationship with trunk muscle mass. CONCLUSIONS: This study demonstrated that trunk muscle mass or trunk muscle thickness can be used as an alternative means for evaluating trunk muscle strength, making the evaluation of trunk muscles less burdensome.

Trip-specific training improves the kinematics of trip-specific compensatory stepping response (CSR) in the laboratory and reduces prospectively measured trip-related fall-rate of middle age and older women. We examined whether one session of trip-specific perturbation training could improve recovery step kinematics in women with knee osteoarthritis (OA), a condition known to increase fall risk. Seventeen women with self-reported symptomatic knee OA (age 61.1 ± 7.7 years, body mass index [BMI] 29.7 ± 5.9 kg/m2 ) and 22 control women (age 59.5 ± 6.8 years, BMI 28.4 ± 6.2 kg/m2 ) completed a brief training protocol consisting of 20 trials of treadmill-delivered trip-specific perturbations. We assessed pre- and post-training recovery step length and trunk kinematics at the instant of recovery step completion. Repeated-measures analysis of variance was used to determine the significance of between-group differences following the training protocol, and to evaluate the significance of within-group pre-to-post changes in the variables of interest. The group by training interaction effects for step length (p = 0.466), trunk flexion angle (p = 0.751), and trunk angular velocity (p = 0.413) were not significant and the pre-to-post changes in step length were not significant (p = 0.286). However, pre-to-post trunk flexion angle improved by 26% and 34% in the OA and control groups, respectively (p < 0.001) and trunk flexion angular velocity decreased by 193% in the OA group and by 32% in the control group, respectively (p < 0.001), often reflecting a transition to the direction of extension. The results suggest that trip-specific training can improve CSR kinematics in women with knee OA. It is important to determine, the effectiveness of trip-specific training in decreasing trip-specific fall-rate by women with knee OA. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:663-669, 2020.

BACKGROUND Chronic stroke survivors demonstrate the potential to acquire reactive adaptations to external perturbations. However, such adaptations in postural stability and compensatory stepping responses are perturbation-type specific and the ability to generalize such adaptation to an opposing perturbation has not been studied. OBJECTIVE The study aimed to examine whether improved reactive balance control acquired through prior slip-perturbation training would positively transfer to, or interfere with, the reactive response to an unexpected novel trip. METHODS Twenty-six chronic stroke survivors were assigned to either the training group (TR) who received treadmill-induced slips (12 m/s2) while standing followed by a novel trip (16.8 m/s2) or the control group (TC) who experienced a single unannounced trip. The primary outcome measure was postural stability (examined by relative center of mass position (RCoMP) and velocity (RCoMV)) with step length and trunk angle being secondary measures. Perturbation outcome (fall vs recovery) and number of compensatory steps were also recorded. RESULTS The TR group showed an anterior shift in RCoMP via longer compensatory backward step and reduced number of steps from first to last slip-perturbation (p

Pose® Method gait retraining has been claimed to modify running form and prevent injury. This study examined the running biomechanics before and after Pose® Method gait retraining. Fourteen runners underwent a 4-week Pose® Method gait retraining program delivered by a certified coach. Paired t-tests were employed to compare vertical average (VALR) and instantaneous loading rates (VILR), lower limb kinematics, footstrike angle and trunk flexion in the sagittal plane before and after the training. Kinetically, there were no significant differences in the VALR (p= 0.693) and VILR (p= 0.782) before and after the training. Kinematically, participants exhibited greater peak hip flexion (p= 0.008) and knee flexion (p= 0.003) during swing. Footstrikeangle also reduced significantly (p= 0.008), indicating a footstrike pattern switch from rearfoot strike to midfoot strike. There was no significant difference in the trunk flexion in the sagittal plane after training (p= 0.658). After a course of Pose® Method gait retraining, runners demonstrated a footstrike pattern switch and some kinematics changes at the hip and knee joint during swing. However, injury-related biomechanical markers (e.g., VALR and VILR) and the trunk kinematics remained similar after training. Runners may consider other gait retraining programs for impact loading reduction.

Low physical capacity is hypothesized to be associated with the presence of musculoskeletal symptoms. Therefore, our aim was to investigate whether physical capacity is associated with the presence of musculoskeletal symptoms in the neck, shoulders, and thoracic and lumbar spine among office workers. Sixty-seven office workers, recruited at the university, were evaluated regarding the presence of musculoskeletal symptoms through the Nordic Musculoskeletal Questionnaire (NMQ). Measurements of muscle strength and endurance of shoulder abduction, endurance of trunk flexion and extension, and back and leg flexibility were obtained. Data were analysed through a binomial logistic regression model, considering physical capacity as the independent variable and symptoms as the dependent variable. An adjusted model was also applied that controlled for individual and occupational covariates. The basic model showed a significant association between reduced shoulder abduction strength and neck (OR: 0.87; 95% CI 0.78–0.98) and shoulder symptoms (OR: 0.88; 95% CI 0.78–0.99), and between reduced back and leg flexibility and thoracic spine symptoms (OR: 0.92; 95% CI 0.85–0.99). The adjusted model, after controlling for the covariates, demonstrated that reduced shoulder abduction strength (OR: 0.70; 95% CI 0.52–0.94) and reduced back and leg flexibility (OR: 0.81; 95% CI 0.66–0.99) were associated, instead, with the occurrence of neck and low back symptoms, respectively, in the last 12 months. Physical capacity is associated with the presence of neck and low back symptoms in office workers. Furthermore, individual and occupational characteristics affect the relationship between physical capacity and musculoskeletal symptoms and should be considered for understanding and managing musculoskeletal symptoms among office workers.

Background Lower extremity sprain and strain injury constitutes a large percentage of lower extremity injuries experienced by soccer players. Yet, very limited data exists on the association between core strength and endurance and this injury. Purpose The purpose of this study was to compare core muscle endurance and hip muscle strength between soccer players who experienced non-contact lower extremity sprain and/or strain injury during their season and those who did not. Additionally, the frequency of injury was correlated with core muscle endurance and hip strength, and endurance was used for predicting the risk for injury. Study design Prospective cohort. Methods Twenty-one (35.59%) athletes experienced non-contact lower extremity sprain and/or strain injury during the season. Fifty-nine male athletes (mean age 20.92 ± 4.08 years, mass 77.34 ± 12.02 kg and height 1.79 ± 0.06m) were tested. Prior to the start of the season, prone-bridge, side-bridge, trunk flexion and horizontal back extension hold times were recorded for endurance assessment and peak hip abductor and external rotator isokinetic torques for strength assessment. Results Prone-bridge and side-bridge hold times were significantly longer in the non-injured players when compared with the times of the injured players (p=0.043 & 0.008 for the prone-bridge and side-bridge, respectively). There were significant negative correlations between the frequency of injury and both prone-bridge (r=-0.324, p=0.007) and side-bridge (r=-0.385, p=0.003) hold times. Logistic regression analysis revealed that side-bridge hold time was a significant predictor of injury (OR=0.956, CI=0.925-0.989). Conclusion Soccer players with non-contact lower extremity sprain and/or strain have less core endurance than non-injured players. Reduced core endurance is associated with increased incidence of injury. Improving side-bridge hold time, specifically, may reduce the risk for injury. Level of evidence 1b.

This study examined the effect of water immersion on trunk and lower limb kinematics during squat exercises in older participants. A total of 24 active older adults (71.4 ± 5.4 years) performed squats and split squats on land and while partially submerged in water. Inertial sensors (100 Hz) were used to record trunk and lower body kinematics. Water immersion increased the squat depth (squat: p = .028, d = 0.63 and split squat: p = .005, d = 0.83) and reduced the trunk flexion range (squat: p = .006, d = 0.76 and split squat: p

Background and purpose. Trunk endurance and extensibility are the main physical condition factors related to back pain. The goal was to analyse the effectiveness of a 6-week Pilates programme on trunk endurance and extensibility in adolescents with a history of back pain, determining the influence of sex. Materials and methods Fifty-two students with a history of back pain were randomly assigned to the Pilates group (PG; n = 26) or the control group (CG; n = 26). Trunk flexion (BTC test) and extension (SOR test), and hamstring extensibility (TT test) were measured. Results PG improved significantly BTC, SOR, and TT test. Statistical differences (p = 0.005) were found between the PG and the CG for the SOR test. Conclusion The Pilates programme enhanced trunk endurance and extensibility in adolescents with a history of back pain. Trunk flexor endurance was better in the PG. Results were not influenced by sex.

The purpose of this study is to present a forward kinematics model of the human lumbar spine and to compare the internal loads and trunk flexion extension with existing literature. The forward kinematics model of lumbar spine with 30 DOF was designed using Solidworks and used Matlab to simulate the results for different postures. The forward kinematics model predicted similar trend for trunk flexion extension, compression force, shear forces and moment as described in literature for in vivo studies. The comparison between the proposed model and in vivo measurement showed a pressure difference of less than 15% on the disc L4-L5 for all activities whereas the compression force and moment differed by ~17% on the disc L5-S1. The modeling methodology presented in this thesis provides a more accurate representation of compression forces and moments of the human lumbar spine since the model makes no assumptions regarding muscle force and does not rely on any other software for kinematics data.

Background Previous research has demonstrated elevated activation of the knee flexor muscles in people with knee osteoarthritis. People with this condition have also been observed to walk with increased trunk flexion; this may alter biomechanical loading patterns and change muscle activation profiles. Therefore, the aim of this study was to understand the biomechanical effect of increasing trunk flexion during walking. Methods Kinetic and EMG data were collected from a sample of 20 people with knee osteoarthritis and a sample of 20 healthy matched controls during normal walking. Using a biofeedback protocol, participants were subsequently instructed to walk with a 5° increase in trunk flexion. Sagittal moments, muscle activations and co-contractions were then compared across a window in early stance with a two-way ANOVA test. Results When trunk flexion was increased, there was a corresponding increase in activity of the medial and lateral hamstrings and gastrocnemius muscles as well as a rise in medial co-contraction. This effect was consistent across the two groups. The most pronounced effect was observed for semitendinosus, which showed a dramatic change in activation profile in the healthy group and a 127% increase in activation during early stance. Conclusions This is the first study to demonstrate that increased trunk flexion in people with knee osteoarthritis may explain, to some degree, the elevated knee flexor activity and medial co-contraction which is associated with this disease. These findings motivate further work to understand the therapeutic potential of interventions designed to improve postural alignment.

Tissue flossing, also called voodoo flossing, is becoming a popular adjunct to athletic training to improve joint range of motion and muscle strength. The authors of this technique believe that tissue flossing can be used during warm-up. This study investigated the effect of tissue flossing during warm-up on the range of motion in the sit and reach test.The study enrolled 40 recreational athletes divided into an experimental and control group consisting of 20 participants each. The range of trunk flexion was assessed with the sit and reach test. Participants were tested before as well as immediately and 15, 30 and 45 minutes after completing the 9-minute warm-up. During the warm-up, athletes in the experimental group wore a floss band on the thigh muscles, while athletes in the control group exercised without wearing a floss band.The sit and reach test revealed an improved range of motion after the warm-up in both groups (P0.05). The improvement was noted at all time points. Regression analysis showed no effect of any of the study parameters (group assignment, sex, age, body mass index, pain intensity on a visual analogue scale) on the improvement in the sit and reach test results.The similar results obtained in both groups indicate that there may not be a rationale for using tissue flossing during warm-up to improve trunk and hip flexibility.

Exoskeletons are an innovation that have been increasingly explored in various fields. In fact, industries are one sector that have been investing in the studies of this new equipment to answer the unnecessary efforts made by the operators, where technical and organizational measures implemented are not enough to reduce the risk exposure to demanding working conditions. Hence, a study was conducted to understand the operator’s perceptions in the workplace regarding the use of a low back passive exoskeleton (Laevo). Ease of performing the different tasks with the use of the exoskeleton, ease of use, discomfort, perceived effort with and without the use of this equipment, acceptance, usability, and intention to use it, were the parameters assessed in this study. The exoskeleton was tested in 3 workstations, by a total of 23 workers during tasks that required trunk flexion, manual material handling or both in an automotive industry. The goal was to develop a pilot test, study the participants' perceptions and opinions, and conclude whether the exoskeletons are ready for the industrial context in non-cyclic processes.

Following our experiences in Italy in Mazara del Vallo and Chioggia Marinas, we had another one in Tunisia in Sfax Marina. Aim of this paper is a biomechanical risk assessment of fishermen working on a vessel smaller than those previously analyzed in Italy and in a different socio-cultural context. The task that involved most of the crew’s working time was the sorting. We assessed this task by ISO Standard 11226 and 3DSSPP software. The maximum recommended exertion duty cycle, listed as a percentage of job time from the 14 analyzed frames with 3DSSPP, was between 2.3 and 14%. This data confirms that workers’ postures during sorting task were critical. In these task workers flexed the trunk over 90° for approximately 10 min for every catch. Both maximum exposure time (1 min) and maximum acceptable trunk flexion (60°) threshold, defined by ISO 11226, were exceeded. Moreover, it should be considered that ISO 11226 does not consider boat instability that significantly impacts biomechanical risks. The maximum posture holding time before the occurence of fatigue, according to Potvin’s mathematical model, is lower than the time held by workers. Trunk maximal values were between 35s and 125s and the lower limb joints values rarely exceeded two minutes of maximum exposure. Estimated values of the percentage of Maximum Voluntary Contraction (%MVC) were between 35% and 61% for the trunk and between 31.4% and 39.2% for the neck. The lower limbs %MVC values were remarkable for the hips (between 28% and 68%), knees (between 31% and 88%) and ankles (between 27% and 94%). This new experience confirmed medium-high risk levels during the sorting process. Furthermore given the reduced size of the boat, the crew couldn’t improve their working conditions with low-cost solutions, as in Italy. For operational problems, manual handling of the fish crates wasn’t assessed although the placement of the freezer on the deck of the boat, instead of the bottom floor as in Mazara del Vallo, is certely less stressful.

Volleyball players and gymnasts need strength training to achieve their optimum sport performance. The aims of this study were to describe body composition, strength, performance, and characteristics of trunk muscle activation in volleyball players and gymnasts, and to analyze the differences between the sports. The sample consisted of 40 female athletes: rhythmic gymnasts (n = 24, age 13.95 &plusmn, 2.77 years) and volleyball players (n = 16, age 19.81 &plusmn, 5.55 years). Body composition, maximum voluntary contraction (MVC) of isometric tests in an isokinetic dynamometer, McGill core endurance test, and surface electromyography (EMGrms) of the trunk muscle during the McGill test and isometric tests were recorded. Rhythmic gymnasts presented lower body composition values than volleyball players (p &lt, 0.05). The volleyball players presented higher isometric strength than rhythmic gymnasts in terms of MVC in trunk flexion (p &lt, 0.05, d = 1.3) and trunk extension (p &lt, 0.001, d = 1.3). EMGrms from the rhythmic gymnasts were greater for trunk flexor muscles (p &lt, 0.01, d = 0.7) and trunk extensor muscles (p &lt, 0.001, d = 1.3) during McGill endurance tests compared to the volleyball players. In the isometric test, EMGrms from the rhythmic gymnasts were greater for trunk flexor muscles in flexion (p &lt, 0.01, d = 0.9) and extension tests (p &lt, 0.05, d = 0.7). In conclusion, the volleyball players exhibited higher peak strength, despite the fact that the gymnasts showed greater muscle activity during the maximum voluntary contraction.

The objectives of this study were to evaluate the effect of gender and postures of the neck, trunk, and knee on overall postural discomfort, and to classify combined postures into different postural discomfort groups. A total of 95 participants (42 males and 53 females) performed 45 different static postures, which were a combination of 3 neck angles, 5 trunk angles, and 3 knee angles, and rated the perceived postural discomfort. Non-hierarchical K-means cluster analysis was employed to classify the 45 different combined postures into several postural discomfort groups. Postural discomfort was significantly affected by gender and postures of the neck, trunk, and knee (p &lt, 0.001). Three clusters (high, medium, and low discomfort) were identified and the postural discomfort was significantly different between clusters (p &lt, 0.001). The high discomfort group consisted of mostly males with high knee and trunk flexion angles and a moderate neck flexion angle. The low discomfort group was female-dominant with low neck and trunk flexion angles and a moderate knee flexion angle. The different flexibility (stiffness) of the joint motions between genders may affect the gender difference in postural discomfort. The knee and trunk postures were critical to the postural balance, which may affect the perception of whole-body discomfort. This result will be useful for developing and improving postural observation tools.

Background Home care providers assisting with seniors' personal care often experience high rates of musculoskeletal disorders, particularly affecting the lower back. Assisting with bathing is consistently identified as one of their most physically demanding activities. Objective To identify and describe care providers' procedures for assisting a frail senior to bathe that are likely to contribute most to the development of back injuries. Methods Eight community-based personal support workers (home care aides) assisted a frail senior (actor) to bathe in a simulated home bathroom. Video recordings of the activity were coded according to providers' postures and to characterize techniques for providing care. Results Exposure to severe trunk flexion and high posture-induced back loads was greatest during transfers in and out of the bathtub. In particular, lifting the legs over the rim of the tub, assisting the client to shift across the bath transfer bench, and providing care to the legs and feet involved the care provider spending substantial time in highly flexed postures. No observed techniques for these activities showed substantially lower exposures. Conclusions Further tools and/or techniques must be identified or developed to improve caregiver safety during these strenuous activities.

Objective The purpose of this study was to investigate the relationship between hamstring flexibility and electromyography (EMG) muscle parameters in back and lower limb extensor muscles during a trunk flexion task. Methods Thirty healthy women aged 18 to 30 years with normal hip movement were recruited for this study. Hamstring muscle flexibility was measured with the 90-90 active straight leg raise test. Surface EMG activities were simultaneously recorded from the lumbar erector spinae, gluteus maximus, biceps femoris, semitendinosus, lateral gastrocnemius, and medial gastrocnemius muscles during forward bending. Muscle activity onset and offset, amplitude, and duration were calculated with technical computer software (MATLAB, version 1.6.0). Linear regression analysis was used to investigate the relationships between hamstring flexibility test results and EMG parameters during trunk flexion. In addition, the Friedman test was used to determine the recruitment activity pattern in women with low versus normal hamstring flexibility. Results During flexion, the back extensor muscles in individuals with lower hamstring flexibility test scores were activated and deactivated later, which can lead to delayed flexion-relaxation. Regression analysis did not disclose any significant correlations between hamstring flexibility and other EMG parameters (duration and amplitude) in back extensor muscles. Activation and deactivation recruitment patterns differed between the groups with normal and low hamstring flexibility. Conclusion The findings of this study suggest that hamstring flexibility plays an important role in the patterns of trunk and lower limb muscle activity onset, offset, and recruitment.

Objectives Undesirable bowling kinematics can increase the risk of low back injury. This study investigated if an exercise-based injury prevention program (IPP) could modify bowling kinematics in community-level adolescent pace bowlers. Design Cluster-randomised controlled trial. Methods Pace bowlers from eight cricket organisations were cluster-randomised into an intervention or control group. At baseline and follow-up sessions biomechanical bowling data were collected. Between sessions, the intervention group completed an eight-week IPP while the control continued their normal cricket activity. Treatment effects (95% CI) were estimated with linear mixed models. Results There were significant treatment effects favouring the intervention group for shoulder counter-rotation (−3.8°; −7.2° to −0.3°) and lateral trunk flexion relative to the pelvis (−2.2°; −4.0° to −0.5°). Shoulder counter-rotation also increased in the control group by 2.2° (Cohen’s d = 0.22). There were no effects of the intervention on: lateral trunk flexion at front foot contact (FFC) (1.2°; −2.5° to 4.8°), lateral trunk flexion at ball release (BR) (−0.5°; −3.0° to 2.0°), pelvis rotation at FFC (0.9°; −4.0° to 2.2°), pelvis rotation at BR (−1.1°; −5.7° to 3.6°), front hip angle at FFC (1.6°; −3.6° to 6.7°), front hip angle at BR (−1.6°; −5.0° to 1.9°), front knee angle at FFC (−1.1°; −4.5° to 2.3°), front knee angle at BR (1.7°; −5.6° to 9.1°), or ball velocity (1.1 km h−1; −7.5 km h−1 to 9.7 km h−1). Conclusions The IPP maintained shoulder counter-rotation and lateral trunk flexion relative to the pelvis in the intervention group and this could attenuate injury risk. No treatment effects were observed for lower-limb kinematics.

The sit-to-stand transfer can be separated into a postural phase (trunk flexion) and a focal phase (whole-body extension). The aim of this study was to analyze the as yet little known whole-body muscular activity characterizing each phase of this task and its variations with backrest inclination and execution speed. Fifteen muscles of the trunk and lower limbs of 10 participants were investigated using surface EMG. Results showed that backrest-induced modifications were mostly confined to the postural phase: reclining the backrest increased its duration and the activity level of the sternocleidomastoideus, the rectus and obliquus externus abdominis, and the semitendinosus. Speed-induced variations were also predominant during the postural phase, which was shortened with an increased activity of most muscles at maximal speed.

Nurses are at increased risk to develop musculoskeletal disorders (in particular low back pain) due to prolonged exposure to awkward postures, but there is a lack of quantitative objective measurements useful to characterize such postures. In the present study, we employed a single wearable inertial measurement unit (IMU) placed in the low back to monitor trunk flexion of eleven professional nurses working at maternity and cardiology wards during two hours of a regular shift. Trunk movement was analyzed using an exposure variation analysis approach which classifies flexion in three classes (i.e. 30–60°, 60–90° and >90°). The results show that tested nurses spent 3.5% of the monitored time with their trunk flexed between 30 and 60° and 0.2% between 60 and 90°. The IMU-based approach appears suitable to perform long-term monitoring of trunk postures in workers at risk for musculoskeletal disorders, overcoming the limitation of the observational methods and questionnaires.

The objective of this study was to develop a five inertial measurement unit (IMU) sensor system attached to the human body for automatically identifying the duration of the lifting task (LD) performed symmetrically with two hands at various hand locations relative to the body, and three other lifting risk variables including the trunk flexion angle (T), the vertical distance (V) and horizontal distance (H) of the lifting task defined by the revised National Institute for Occupational Safety and Health lifting equation (RNLE). The algorithm that processed the IMU data consisted of two modules: the synchronization module that extracted the synchronization feature of wrists’ motion data to identify the lifting event; and the lifting variable calculations module that employed a body segment length ratio model for calculating the risk variables. The variable calculation module was further modified to include subjects’ body segment length information for improved accuracy. The wearable system was validated by motion data collected by a laboratory grade motion capture system on 10 human subjects performing 360 lifting trials. Results showed that the model performed well for determining the LD (~1 s error) and T (~2° error). However, the mean errors for V and H were large (33 and 6.5 cm, respectively). Inclusion of subjects’ five body segment length measurements improved the mean errors of V and H to 14 and 2.2 cm, respectively.

Lateral trunk flexion (LTF) is a common postural deformity in Parkinson’s disease (PD). Postural control is known to depend on visual, vestibular, and somatosensory information. This study aimed to investigate the relationship between vestibular dysfunction and postural abnormalities in PD patients with LTF. We enrolled a total of 19 PD patients with LTF (PD-LTF+) and 19 age- and sex-matched PD patients without LTF (PD-LTF-). All patients underwent vestibular tests, including spontaneous nystagmus, gaze-evoked nystagmus, ocular movements, optokinetic eye test, fast positioning maneuvers, and the bithermal caloric test. Most of the PD-LTF + patients had abnormal vestibular function (11/19), while there were fewer vestibular function injuries in the control group (3/19). In PD-LTF + group, there were 5 patients (5/11, 45.5%) of peripheral vestibular dysfunction, 2 patients (2/11, 18.2%) of central vestibular damage, and 4 patients (4/11, 36.4%) of mixed injuries. The peripheral vestibular deficiencies could be either bilateral (4/9, 44.4%) or unilateral (5/9, 55.6%). The unilateral vestibular dysfunction was ipsilateral to the leaning side in 2 patients and contralateral to the leaning side in the other 3 patients. Vestibular dysfunction may be an independent risk factor for LTF in PD patients.

Background: People with Parkinson&rsquo, s disease (PD) present deficits of the active range of motion (ROM), prominently in their trunk. However, if these deficits are associated with axial rigidity, the functional mobility or health related quality of life (HRQoL), remains unknown. The aim of this paper is to study the relationship between axial ROM and axial rigidity, the functional mobility and HRQoL in patients with mild to moderate PD. Methods: An exploratory study was conducted. Non-probabilistic sampling of consecutive cases was used. Active trunk ROM was assessed by a universal goniometer. A Biodex System isokinetic dynamometer was used to measure the rigidity of the trunk. Functional mobility was determined by the Get Up and Go (GUG) test, and HRQoL was assessed with the PDQ-39 and EuroQol-5D questionnaires. Results: Thirty-six mild to moderate patients with PD were evaluated. Significant correlations were observed between trunk extensors rigidity and trunk flexion and extension ROM. Significant correlations were observed between trunk flexion, extension and rotation ROM and GUG. Moreover, significant correlations were observed between trunk ROM for flexion, extension and rotations (both sides) and PDQ-39 total score. However, these correlations were considered poor. Conclusions: Trunk ROM for flexion and extension movements, measured by a universal goniometer, were correlated with axial extensors rigidity, evaluated by a technological device at 30&deg, /s and 45&deg, /s, and functional mobility. Moreover, trunk ROM for trunk flexion, extension and rotations were correlated with HRQoL in patients with mild to moderate PD.