Kinematic Patterns Research Articles

The Influence of Contextual and Theoretical Expertise on Generic and Occupation-Specific Lifting Strategy.

To determine whether (i) low back loads and/or (ii) kinematic coordination patterns differed across theoretical expert, contextual expert and novice groups when completing both generic and occupation-specific lifts. Experience has been proposed as a factor that could reduce biomechanical exposures in lifting, but the literature reports mixed effects. The inconsistent relationship between experience and exposures may be partially attributable to the broad classification of experience and experimental lifting protocols not replicating the environment where experience was gained. Purposive sampling was used to recruit 72 participants including theoretical experts (formal training on lifting mechanics), contextual experts (paramedics), and novices. Participants performed 10 barbell and crate (generic) lifts, as well as backboard and stretcher (occupation-specific) lifts while whole-body kinematics and ground reaction forces were collected. Peak low back compression and anteroposterior shear loads normalized to body mass, as well as kinematic coordination patterns, were calculated as dependent variables. No significant differences in low back loads were observed across expertise groups. However, significant differences were seen in kinematic coordination patterns across expertise groups in occupation-specific lifts, but not in generic lifts. Increasing expertise is unlikely to minimize low back loads in lifting. However, contextual expertise did influence lifting kinematics, but only when performing occupationally specific lifts. Contextual expertise may help lifters adopt lifting kinematics that enhance the tolerance of their musculoskeletal system to withstand applied loads, but does not seem to reduce the applied low back loads relative to noncontextual expert groups.

Characteristics of throwing arm movement for an elongated implement: a comparison of the javelin and baseball throwing.

In javelin, although many previous studies have examined throwing movements that can increase initial velocity, the characteristics of throwing arm movement an elongated implement have not been clarified. The purpose of the present study was to examine the characteristics of the throwing movement of an elongated implement by comparing throwing movement between a javelin and baseball. Twelve male javelin throwers were asked to perform a javelin throw (JT) and a baseball long toss (LT) twice. The three-dimensional coordinates of reflective markers attached to the athlete's body, javelin, and baseball were measured using an optical motion capture system. %Trajectory was used as an index to evaluate the degree to which the hand was moved linearly during the throw. A smaller value of this indicator meant that the hand was move closer to a straight line. The joint angles in the throwing arm were obtained by calculating the Euler angles between body segments. These data were used to compare JT and LT. %Trajectory showed that JT was significantly smaller than LT. Significant differences in the joint angles of the throwing arm were noted between JT and LT. JT showed a kinematic pattern in which the hand was moved more linearly than in baseball long toss.

Effect of quercetin, L-ergothioneine and H89 on sperm motility and kinematic pattern, plasma membrane functionality and in vitro heterologous fertilizing capacity of cryopreserved equine semen

Semen cryopreservation causes extensive chemical and physical damage to sperm structure, which generates premature aging and reduces viability and fertility of spermatozoa. The addition of antioxidants to freezing extenders can reduce the oxidative damage caused by excessive generation of reactive oxygen species (ROS), and the premature aging could be reduced by adding an enzyme inhibitor that prevents an anticipated capacitation. The aim of this study was to evaluate the in vitro effect of quercetin (Q), L-ergothioneine (E) and H89 addition to cryopreserved equine spermatozoa. Six experimental groups were stablished: control, Q, E, H89, H89Q and H89E. The analyzed parameters were sperm motility and kinematic using computer assisted sperm analysis (CASA), plasma membrane functionality with the hypoosmotic swelling test (HOST) and fertilizing capability with in vitro heterologous fertilization. Quercetin reduced curvilinear velocity (VCL) and increased beat-cross frequency (BCF), while its combination with H89 (H89Q) reduced total motility, progressive motility, VCL and hyperactive sperm (HA). Likewise, H89 and its combination with E (H89E) decreased VCL and amplitude of lateral head displacement (ALH). No significant differences were observed among treatments for membrane functionality and fertilizing capacity of sperm. In conclusion H89 in combination with Q and E reduced sperm motility or some kinematic parameters. However, they did not influence plasma membrane functionality and in vitro fertilizing capacity of frozen-thawed equine semen.

Kinematic Analysis of Pelvic and Lower Limb Joints during Stand-to-sit Movement in Individuals with Chronic Low Back Pain: A cross-sectional study.

It is crucial to investigate the daily functions commonly utilized by individuals with low back pain (LBP) due to their implications for recurrence and chronicity. Stand-to-sit (StTS) task is one of the more repetitive functions in human daily life. This study aims to evaluate pelvic and lower limb joint kinematics during the StTS task in individuals with Non-Specific Chronic Low Back Pain (NSCLBP) compared to a healthy control group. Pelvic and lower limb joint kinematic data in all three planes were recorded from 20 individuals with LBP and 20 healthy individuals using a Qualisys motion capture system during the StTS task. A Functional Data Analysis statistical approach was employed to compare the kinematic data between the two groups. In the initial phase of the movement, we observed a greater anterior pelvic tilt (P=0.028) and an altered pelvic frontal plane motion pattern (P=0.029) in the LBP compared to the healthy group. The only significant differences between the lower limb joint kinematics of the two groups were a less hip external rotation position (P=0.025) and a more knee adduction pattern (P=0.002) on the right side in the LBP subjects compared to the healthy group. Considering a few differences noted between the two groups across various joints and planes evaluated, it appears that the kinematic pattern of the lower limbs does not significantly differ between the NSCLBP and healthy groups during the StTS task in most comparisons. However, distinct kinematic patterns have been observed in the pelvic region, particularly in the sagittal and frontal planes, between the two groups.

The knee kinematic patterns and associated factors in healthy Thai adults

BackgroundReference values for normal knee kinematics were limited in Asian population and were influenced by race and other factors. This study was aimed to establish the reference values and identify the factors associated with knee kinematics in healthy Thai adults, aged 18–40 years.MethodsA retrospective cohort study was conducted between 2016 and 2020. Healthy Thai adults aged 18–40 years old with body mass index (BMI) between 18.5 and 24.9 kg/m2 were included. All eligible participants were attached with reflective markers. Their walking was captured by 8-digital cameras, and assessed by motion analysis software. The primary outcomes were average knee kinematic data (degrees) in three dimensional planes as valgus-varus, flexion-extension, and internal-external rotation. Paired t-test and multiple linear regression were applied to compare the outcomes and to determine their associated factors.ResultsNinety-eight participants (60 females and 38 males) were included with mean age 28.5 ± 5.4 years, and BMI 21.1 ± 2.0 kg/m2. Knee kinematics showed slight adduction during the swing phase, flexion during the stance phase, and obvious external rotation throughout the gait cycle, with a peak of 30–31 degrees during mid-swing. Right knee was significantly more adducted, flexed and externally rotated than the left side, particularly at mid-stance (P = 0.047, 0.017, and < 0.001, respectively). Females had more knee abduction, flexion and external rotation than males. Age, sex, and BMI were significantly correlated with knee abduction at terminal stance (correlation coefficient − 0.12, 95% confidence interval (CI) -0.23, -0.01; -1.37, 95%CI -2.54, -0.20; and − 0.32, 95%CI -0.61, -0.39, respectively), and rotation at mid-swing (correlation coefficient − 0.36, 95%CI -0.69, -0.02; -7.37, 95%CI -10.82, -3.92; and 0.89, 95%CI 0.01, 1.78, respectively).ConclusionKnee kinematics demonstrates external tibial rotation throughout the gait cycle, significant side differences, and are associated with age, sex, and BMI. Reference values from this study will be useful for functional gait assessment in healthy Thais. However, further comprehensive knee kinetic study including spatio-temporal parameter is recommended.

JoyPose: Jointly learning evolutionary data augmentation and anatomy-aware global–local representation for 3D human pose estimation

Video-based 3D human pose estimation is an important yet challenging task for many human-involved pattern recognition systems. Existing deep learning-based 3D human pose estimation methods are faced with the problems of lacking large-scale training data and lacking effective solutions to represent the complicated human body structure. To this end, this paper proposes a jointly learning framework entitled JoyPose that simultaneously leverages both human pose data augmentation and human pose estimation. In particular, JoyPose consists of an evolutionary data augmentation module and an anatomy-aware global–local pose feature representation module for 3D human pose estimation. The evolution for data augmentation is guided by a reinforcement learning strategy in a probabilistic way according to pose estimation loss. The anatomy-aware global–local pose feature representation module separately captures global features and local features according to anatomical and kinematic patterns observed from pose estimation errors across different human joints. The performance of the final human pose estimation is leveraged by both data augmentation and anatomy-aware global–local feature representation. Extensive experiments on three real-world datasets demonstrate the superiority and robustness against state-of-the-art methods.

Preserving primary medial static stabilizer ligaments achieves physiological knee kinematics in total knee arthroplasty

PurposeAs postoperative knee instability has been reported to be one of the critical reasons for early failure in total knee arthroplasty (TKA), obtaining optimal knee stability—especially in medial—was indispensable for successful TKA. We hypothesized that preserving medial soft tissue structures was the key to maintain physiological medial knee stability. Thus, TKAs with preserving primary medial static stabilizer ligaments technique were performed, and the postoperative knee kinematics was evaluated. MethodsPrimary knee osteoarthritis patients with varus knee deformity and planed for primary TKA were enrolled. However, patients with severe varus knee deformities, valgus knee deformities, and rheumatoid arthritis were excluded. TKAs were performed by removing medial femoral and tibial osteophytes; however, the primary medial static stabilizer ligaments—the superficial medial collateral ligament (MCL), deep MCL, and posterior oblique ligament—were not released. The cruciate-retaining (CR), posterior-stabilized (PS), and medial-pivot (MP) inserts were implanted, and the knee kinematics was measured. These data were statistically analyzed using analysis of variance. The institutional review board approved the study. ResultsFrom full extension to maximum flexion, the lateral femoral condyle moved backward, greater than the medial femoral condyle, and consequently the femur external rotated on the tibia. These kinematics patterns were shown in CR, PS, and MP groups. ConclusionAs the knee kinematics of CR and PS are similar to that of MP, which has been reported to demonstrate physiological knee kinematics, preserving primary medial static stabilizer ligaments technique could potentially preserve physiological knee kinematics.

Effects of Nobiletin supplementation on the freezing diluent on porcine sperm cryo-survival and subsequent in vitro embryo development

Nobiletin (NOB) is a bioflavonoid compound isolated from citrus fruit peels. The present study aimed to elucidate whether NOB facilitates the porcine sperm cryosurvival and embryo development after in vitro fertilization (IVF). To this end, spermatozoa were diluted and cryopreserved in a freezing extender supplemented with 0 (control), 50, 100, 150, and 200 μM Nobiletin. The kinematic patterns of frozen-thawed (FT) sperm were assessed after 30 and 90 min incubation using a Sperm Class Analyzer (SCA). Viability, acrosome integrity, and mitochondrial membrane potential (MMP) were measured by fluorescence microscopy 30 min after thawing using SYBR-14/PI, PSA/FITC, and R123/PI, respectively. Lipid peroxidation was determined using MDA assay after incubation for 90 min. The addition of 100 μM and 150 μM NOB to the extender significantly improved sperm progressive motility, and acrosome integrity compared to the control group (P < 0.05). The proportion of viable spermatozoa was significantly higher in the 150 μM NOB group. MDA levels were less in 50 μM and 150 μM NOB treated groups compared to the control. In addition, IVF with FT sperm was used to assess the embryo developmental competence. Treatment with 150 μM NOB before cryopreservation increased the cleavage and blastocyst formation rates compared to the control group. Furthermore, the relative expression of POU5F1 and AMPK, genes related to pluripotency and cell differentiation were significantly upregulated in embryos resulting from NOB-treated sperm compared to the control group. These results suggest that Nobiletin is a functionally novel phytochemical to mitigate oxidative stress during the freezing-thawing of porcine spermatozoa as reflected by improved FT sperm quality and IVF outcome.

Geological structure and Mesozoic-Cenozoic tectonic evolution of the Nenya-Chumysh basin (Southern Salair, southern Western Siberia)

Research subject. The Nenya-Chumysh basin is a long-term Mesozoic intracontinental sedimentary basin confined to the zone of a regional fault separating the Salair from the structures of Gorny Altai, Gornaya Shoria, and the Kuznetsk basin. Aim. To establish the geological and structural-kinematic characteristics of impulses of intracontinental orogeny that took place during the Mesozoic and Cenozoic in the territory of the northwestern part of the Altai-Sayan Folded Area. Materials and Methods. Geological maps of the area, geophysical data on the position of the base of the Paleozoic basement, satellite images and digital elevation models were used. The sedimentary filling of the basin is considered as a chronicle of tectonic movements in the NW part of the Altai-Sayan Folded Area at the intracontinental stage of development. Results. The Early Jurassic, Early Cretaceous, Late Cretaceous-Paleogene, and Neogene-Quaternary tectonic stages of the development of the Nenya-Chumysh basin were distinguished. In the Early Jurassic, the Nenya-Chumysh basin was a pull-apart basin in a left-hand strike-slip zone. This stage is associated with the accumulation of coal-bearing deposits of the Glushinskaya Formation, the thickness of which in the Nenya-Chumysh basin reaches about 1900 m. In the Early Cretaceous, as a result of changes in the stress field, the Nenya-Chumysh basin was transformed into a thrust basin, composed of terrigenous deposits of the Ilek Formation, forming a wedge-shaped sedimentary basin characteristic of foreland troughs. The neotectonic structure of the Nenya-Chumysh basin, formed in the stress field of the Indo-Eurasian collision, inherits an older structural plan in general terms, although differing in details. A non-inherited structure is the transverse neotectonic uplift of the Sary-Chumysh swell. Conclusions. The Early Jurassic stage is related with the closure of the Paleo-Tethys and the collision of a series of Cimmerian terranes with the southern margin of Eurasia, Early Cretaceous stage is caused with Mongol-Okhotsk collision, and the Cenozoic stage proceeds with the ongoing Indo-Eurasian collision. The geological evolution of continental sedimentary basins controlled by regional faults can be used as a source of information about the intensity and kinematic pattern of impulses of intracontinental orogeny in the geological past.

Evidence of motor intentions in plants: A kinematical study.

"How" an action is performed is not solely determined by biomechanical constraints, but it depends on the agent's intention, that is, "why" the action is performed. Recent findings suggest that intentions can be specified at a tangible and quantifiable level in the kinematics of movements; that is, different motor intentions translate into different kinematic patterns. In the present study, we used 3D kinematical analysis to investigate whether the organization of climbing plants' approach-to-grasp action is sensitive to the kind of intention driving their movement toward potential support, namely individual or social. For the individual condition, a plant in isolation acted upon the support. For the social condition, two plants were located in the same pot opposite to each other with a support in the middle. Results indicate differences in kinematics depending on the context within which the plant is acting. In the presence of neighbors, climbing plants are able to modify their behaviors to maximize their long-term gains, including the grasping of a potential support. Overall, these data suggest that the organization of climbing plants' kinematics is sensitive to the "intention" driving their movement toward a potential support. To discuss this phenomenon, we capitalize on the concept of motor intentionality in plants and on available theories concerned to motor cognition. We suggest how they could be revisited to explain the intentionality component inherent in plant life and other brainless organisms. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Exploration of semen quality analyzed by casa-mot systems of brahman bulls infected with BLV and BHV-1

Enzootic bovine leukosis virus (BLV) and bovine herpesvirus 1 (BHV-1) are very important infectious agents for the livestock industry worldwide. The present study aimed to explore the association between natural exposure to BLV and BHV-1 with sperm quality analyzed by Computer-Assisted Semen Analysis (CASA) systems. Ten sexually mature Brahman bulls, with sanitary status BLV+/BHV-1+ (n = 2), BLV−/BHV-1+ (n = 6) and BLV-/BHV-1- (n = 2) were evaluated twice, 30 days apart. Results showed that sanitary status of each bull was not associated with semen quality. It was found that the quality of the semen from the second collection was better due to the interruption of sexual rest. The evidence thus revealed that a bull infected with BLV generated good-quality contaminated semen and, therefore, that it is essential to detect contaminated seminal samples to prevent the spread of BLV. A multivariate analysis showed the presence of four sperm subpopulations in Brahman bulls that differ significantly in their kinematic patterns and with respect to sanitary status (P < 0.05), indicating that infection-free and seronegative bulls present the best kinematic parameters, which improved discrimination of sperm quality according to sanitary status. Overall, the analyses indicate that the seropositive-infected bulls with BLV and BHV-1 should be excluded from beef cattle farms.

A new steel – UHPFRC composite beam with in-built composite dowels as connectors: Concept and design principles

Aiming at the full and proper exploitation of both steel and Ultra High Performance cementitious Fiber Reinforced Composites (UHPFRC) materials, this paper proposes a new steel-UHPFRC composite beam structure. The unique use of ① UHPFRC in both tension and compression and ② a half rolled section with continuous in-built steel dowels in combination with UHPFRC dowels (forming composite dowels as shear connectors) is highlighted. An experimental study consisting of two composite beams is then conducted to investigate the flexural and shear responses. In particular, the failure mode, cracking pattern, and monitoring of critical crack kinematics are discussed using digital image correlation (DIC) technology. Subsequently, the design principles for both flexural and shear resistance are introduced based on the failure mechanism: ① the determination of flexural resistance is based on the sectional analysis considering the tensile properties of UHPFRC, and ② the determination of shear resistance is based on a specific approach to the lever arm of internal forces and horizontal shear resistance of the composite dowel, considering the tensile contribution of UHPFRC. According to the experimental results, the effective interlocking between UHPFRC and the steel dowel allows efficient interaction between steel and UHPFRC components, benefiting from its higher shear resistance and ductility compared with traditional welded head studs. Both the flexural and shear response of the composite beam can be characterized into five distinguished domains, in which the quasi-elastic domain is introduced especially due to its large contribution to the resistance and high structural stiffness. Finally, the design principles are validated by the tested values.

Magnetic flux rope structures associated with filament channels: Two case studies

We report on two case studies regarding the magnetic flux rope (MFR) structure of coronal mass ejections (CMEs) near the Sun and at 1 au. The event is a stealth streamer blow-out CME on 2011 March 25 from AR11176 showing a typical three-part bubble-like flux rope structure. No apparent eruptive signatures (e.g., two-ribbon flare, and post-eruption arcade (PEA)) were detected in the solar disk images; but a faint eruptive prominence (EP) was seen at the limb in STEREO EUV images along with a few confined flares before the eruption. The second event is a CME on 2018 August 20 originating from a quiescent filament region with clear two-ribbon flare and PEA observed; and the prolonged CME acceleration coincides with the GOES X-ray flare light curve and reconnected (RC) flux (Gopalswamy et al., 2022). In both cases, a well-defined magnetic cloud (MC) is detected at 1 au after ∼5 days. The two MCs have similar magnetic field magnitude and poloidal flux, however, the RC fluxes estimated from the associated solar source regions are significantly different. Our detailed analysis suggests the following. 1) The two events share a similar kinematic pattern consisting of a slow-rise phase and a main acceleration phase. 2) In the first case, the RC flux of the associated trigger flare at AR11176 is much smaller than the MC poloidal flux at 1au, and a significant amount of poloidal flux has been added through reconnection during the eruption. 3) Both cases show that the post-eruption flux rope has a lower twist at the core and a higher twist at the edge of the flux rope. In addition, we find that the MCs may deviate from a force-free state at the edge of flux rope. A non-force-free, varying-twist Gold-Hoyle (GH) model provides a better fit to the boundaries of the flux rope than the Lundquist (LQ) fit.

Quantifying how functional and structural personal factors influence biomechanical exposures in paramedic lifting tasks

It is unknown how structural (sex, stature, body mass) and functional (strength, flexibility) personal factors influence lifting strategy in paramedic work. We explored whether variance in peak low back forces and kinematic coordination patterns could be explained by structural and functional personal factors in paramedic lifting tasks. Seventy-two participants performed backboard and stretcher lifts. Peak low back forces normalised to body mass, as well as kinematic coordination patterns, were calculated as dependent variables. Being female, stronger, shorter, having higher body mass, and/or having greater lower body range of motion (ROM) were all independently associated with lower normalised low back forces across backboard and stretcher lifting. Females and stronger individuals seemed to define a movement objective to consistently minimise compressive forces, while individuals with greater hip ROM consistently minimised anteroposterior shear forces. The efficacy of improving strength and hip ROM to reduce low back forces in paramedic lifting should be investigated. Practitioner summary: Females, stronger individuals, and individuals with greater hip range of motion consistently exhibited lower normalised low back forces in paramedic lifting. Improving strength and hip range of motion via training is a potential proactive ergonomics approach to reduce peak low back forces in paramedic lifting tasks.

Metallicities of Classical Cepheids in the Inner Galactic Disk

Metallicity gradients refer to the sloped radial profiles of the metallicities of gas and stars and are commonly seen in disk galaxies. A well-defined metallicity gradient of the Galactic disk is observed particularly well with classical Cepheids, which are good stellar tracers thanks to their period–luminosity relation, allowing precise distance estimation and other advantages. However, the measurement of the inner-disk gradient has been impeded by the incompleteness of previous samples of Cepheids and the limitations of optical spectroscopy in observing highly reddened objects. Here we report the metallicities of 16 Cepheids measured with high-resolution spectra in the near-infrared YJ bands. These Cepheids are located at 3–5.6 kpc in Galactocentric distance, R GC, and reveal the metallicity gradient in this range for the first time. Their metallicities are mostly between 0.1 and 0.3 dex in [Fe/H] and more or less follow the extrapolation of the metallicity gradient found in the outer part, R GC > 6.5 kpc. The gradient in the inner disk may be shallower or even flat, but the small sample does not allow the determination of the slope precisely. More extensive spectroscopic observations would also be necessary for studying minor populations, if any, with higher or lower metallicities that were reported in previous literature. In addition, the 3D velocities of our inner-disk Cepheids show a kinematic pattern that indicates noncircular orbits caused by the Galactic bar, which is consistent with the patterns reported in recent studies on high-mass star-forming regions and red giant branch stars.

How saddle height changes the hip kinematics pattern in different degree of freedom

How saddle height changes the hip kinematics pattern in different degree of freedom

Kinematic Pattern Adherence Following Telehealth Gait Retraining In Military Personnel

Kinematic Pattern Adherence Following Telehealth Gait Retraining In Military Personnel

Investigation with able-bodied subjects suggests Myosuit may potentially serve as a stair ascent training robot

Real world settings are seldomly just composed of level surfaces and stairs are frequently encountered in daily life. Unfortunately, ~ 90% of the elderly population use some sort of compensation pattern in order to negotiate stairs. Because the biomechanics required to successfully ascend stairs is significantly different from level walking, an independent training protocol is warranted. Here, we present as a preliminary investigation with 11 able-bodied subjects, prior to clinical trials, whether Myosuit could potentially serve as a stair ascent training robot. Myosuit is a soft wearable exosuit that was designed to assist the user via hip and knee extension during the early stance phase. We hypothesized that clinical studies could be carried out if the lower limb kinematics, sensory feedback via plantar force, and electromyography (EMG) patterns do not deviate from the user’s physiological stair ascent patterns while reducing hip and knee extensor demand. Our results suggest that Myosuit conserves the user’s physiological kinematic and plantar force patterns. Moreover, we observe approximately 20% and 30% decrease in gluteus maximus and vastus medialis EMG levels in the pull up phase, respectively. Collectively, Myosuit reduces the hip and knee extensor demand during stair ascent without any introduction of significant compensation patterns.

Kinematic analysis of movement patterns during a reach-and-grasp task in stroke patients.

This study aimed to evaluate the kinematic movement patterns during a reach-and-grasp task in post-stroke patients according to the upper extremity impairment severity. Subacute stroke patients (n = 46) and healthy controls (n = 20) were enrolled in this study. Spatiotemporal and kinematic data were obtained through 3D motion analysis during the reach-and-grasp task. Stroke patients were grouped using the Fugl-Meyer Assessment (FMA) scale, and a comparison of the groups was performed. The severe group showed a significantly longer movement time, lower peak velocity, and higher number of movement units than the mild group during the reach-and-grasp task (p < 0.05). Characteristic compensatory movement patterns, such as shoulder abduction, thoracic posterior tilting, and upward and external rotation were significantly greater during the forward transporting phase in the severe group than in the mild group (p < 0.05). The FMA score was significantly associated with the movement time during the forward transporting phase, number of movement units during the reaching phase, range of shoulder abduction-adduction and wrist flexion-extension movements during the reaching phase, and range of thoracic internal-external rotation during the backward transporting phase (p < 0.05). Post-stroke patients have unique spatiotemporal and kinematic movement patterns during a reach-and grasp-task according to the impairment severity.

The Spatiotemporal Dynamics of Facial Movements Reveals the Left Side of a Posed Smile.

Humans can recombine thousands of different facial expressions. This variability is due to the ability to voluntarily or involuntarily modulate emotional expressions, which, in turn, depends on the existence of two anatomically separate pathways. The Voluntary (VP) and Involuntary (IP) pathways mediate the production of posed and spontaneous facial expressions, respectively, and might also affect the left and right sides of the face differently. This is a neglected aspect in the literature on emotion, where posed expressions instead of genuine expressions are often used as stimuli. Two experiments with different induction methods were specifically designed to investigate the unfolding of spontaneous and posed facial expressions of happiness along the facial vertical axis (left, right) with a high-definition 3-D optoelectronic system. The results showed that spontaneous expressions were distinguished from posed facial movements as revealed by reliable spatial and speed key kinematic patterns in both experiments. Moreover, VP activation produced a lateralization effect: compared with the felt smile, the posed smile involved an initial acceleration of the left corner of the mouth, while an early deceleration of the right corner occurred in the second phase of the movement, after the velocity peak.