Kinematic Sequence Research Articles

Kinematic Sequence Classification and the Relationship to Pitching Limb Torques.

The kinematic sequence (KS) during a baseball pitch provides insight into an athlete's ability to efficiently transfer energy and develop segmental velocities, to assess the quality of body segment position and control. Study purposes were 1) to introduce the four-category Kinematic Sequence Classification System and 2) to compare elbow and shoulder torques and shoulder distraction force across the KS categories performed during the fastball pitch. Thirty baseball pitchers (20.0 ± 3.1 yr) underwent 3D biomechanical pitch analyses of 249 fastball pitches. Seventeen distinct KS patterns were identified and assigned into four categories: 1) The proximal-to-distal (PDS) group includes the KS closest to theoretical ideal order of the five body segments (pelvis → trunk → arm → forearm → hand). The other categories were defined based on the segment where the first out-of-sequence peak angular velocity occurred: 2) distal upper extremity (DUE), 3) proximal upper extremity, and 4) pelvis/trunk. Throwing limb shoulder distraction force and shoulder and elbow torques were calculated. Linear mixed model analyses compared variables across KS categories. Average elbow valgus torques differed significantly across all categories, P = 0.023, and were greater for the DUE (73.99 ± 20.84 N·m) than the PDS (61.35 ± 16.79 N·m), P = 0.006. Shoulder external rotation torques were significantly different, P = 0.033, across categories. The PDS group demonstrated less mechanical stresses on the throwing shoulder and elbow but was observed in only 12% of pitches. The DUE group was the most common and generated the greatest elbow valgus and shoulder external rotation torques. The KS can inform coaches and sports medicine clinicians where the greatest torques are incurred by a pitcher. A KS classification system may serve as a screening tool or target pitching instruction for injury avoidance.

Kinematic sequence and time lag for pitch and lob shots in female pro-golfers

ABSTRACT This study aimed to determine the differences in the kinematic sequence and time lag of body segments for shots (pitch and lob shots) at different distances (20 and 30 m) around the green. Ten skilled female golfers participated voluntarily. A repeated-measures one-way analysis of variance was performed to assess the effect of the peak angular velocity of the shots (20-m pitch, 30-m pitch, 20-m lob, and 30-m lob shots) on the segments and the effect of the peak angular velocity and time lag of the body segments (pelvis, thorax, upper arm, forearm, and hand) on the shots. All shots taken revealed a summation effect of velocity from proximal to distal body segments, regardless of the shot type (pitch or lob shot) or distance (20 or 30 m). The peak angular velocity of the body segments demonstrated that the velocities associated with the 30-m shots were significantly higher than those associated with the 20-m shots, and the velocities associated with lob shots were significantly higher than those associated with pitch shots, irrespective of the shot distance. This study provided additional insight into the mechanism for improving performances in the shots around the green.

The Kinematic Sequence Of The Baseball Bat Swing And Associated Upper Extremity Torques

PURPOSE: The Kinematic Sequence (KS) is the timing of peak angular velocities generated across connected body segments during a movement pattern. The most efficient KS reported in sport is when the timing occurs in a proximal-to-distal (PDS) pattern. This ‘ideal’ KS follows the order of pelvis, trunk, arm, forearm, and hand. Based on simulated models of the golf swing, the PDS KS results in greater ball distance and decreased joint stresses. Despite similarities to the golf swing, there is limited research on the KS during batting. Study aims: 1) Identify KSs during the baseball swing and 2) compare the leading upper extremity torques across the 3 primary KSs. METHODS: 23 baseball players (professional=2, collegiate=11, high school=10) underwent 3D biomechanical swing analysis, totaling 47 trials. A 15-segment model was constructed using a 20 Vicon™ camera motion capture system (240 hz). Body segment and bat velocities as well as peak shoulder and elbow torques were calculated using Visual 3D™ biomechanical software. Time of peak angular velocity of the pelvis, trunk, arm, forearm, and hand was recorded. The torques were compared across the two most performed KS patterns as well as the KS representing the closest to a PDS pattern. The KS patterns were labeled by the first body segment that disrupted the PDS pattern: proximal (PUE) and distal (DUE) upper extremity. Analyses included an ANCOVA using bat velocity as a covariant. RESULTS: 11 unique KS patterns were identified. The most commonly performed KSs were DUE (n=23) then PUE (n=13). No batter displayed the exact PDS KS. Therefore, 5 trials that most closely represent the PDS, those with forearm and hand velocities peaking simultaneously, were grouped as PDS. Peak elbow extension torque differed significantly between the 3 KS groups (F(2,37)=4.95, η2=0.21, p=0.012) with lower values for PDS (PDS: 17.94 ± 12.83 Nm, PUE: 51.09 ± 25.19 Nm, DUE: 43.01 ± 22.26 Nm, p=0.012). CONCLUSIONS: This foundational study is the first to apply a KS classification system to the baseball swing. Lower elbow extension torques for the PDS group are consistent with the idea that a PDS KS may result in decreased joint stress. KS analyses could potentially guide clinicians and hitting instruction to minimize biomechanical risk factors during batting.

The Relationship Of The Kinematic Sequence And Shoulder Compression Forces During Fastpitch Softball

INTRODUCTION: The Kinematic Sequence (KS) refers to the order of peak angular velocities of connected body segments during a specific movement. There are many possible KS patterns. The proximal-to-distal sequence (PDS) KS ordered: pelvis-> trunk-> arm-> forearm-> hand is reported as the most efficient pattern for overhead throwing. Simulation studies report that the PDS KS results in reduced torques across the joints of the overhead throwing limb, potentially reducing risk of injury. Another KS is the PDS Variant which has a similar PDS pattern of pelvis-> trunk-> arm->, but with simultaneous forearm & hand peak velocities. A third KS pattern, Delayed CORE, demonstrates delayed peak velocity of the trunk: pelvis-> hand -> trunk-> simultaneous arm & forearm. While the PDS KS concept is instructed in fastpitch softball pitching, KS studies have not been published. The study purpose was to investigate the KS in a group of fastpitch softball pitchers. METHODS: 3D biomechanical analyses using high-speed motion capture cameras (240Hz) were performed on 140 fastball pitches from 21 softball pitchers (16 high school, 5 collegiate, mean age 16.15 ± 2.31 y). For each fastball pitch, Visual 3D v6 biomechanical analysis software calculated the peak angular velocity of the pelvis, trunk, arm, forearm and hand after the time of stride which allowed KS identification. Shoulder compression forces and stride length was also calculated for each of 3 primary groups of fastball pitches PDS n =12, PDS Variant n= 28 and the Delayed CORE n= 27. ANOVA and T-test comparisons were performed. RESULTS: There were no significant differences in stride length between the 3 KS patterns, p = 0.14. The Delayed CORE KS pattern demonstrated statistically significantly greater shoulder compressive force than the other groups, mean= 8.23 ± 1.04 (F(2,64)= 23.45, p< 0.01). There were no differences in shoulder compression forces between the PDS (6.89BW ± 0.5) and the PDS Variant (6.74BW ± 0.73) group, p= 0.524. CONCLUSION: This foundational study is the first to apply a KS classification system to the fastball softball pitch. Use of the PDS or PDS Variant KS promoted less shoulder compression force than the Delayed CORE group. The KS classification system could potentially guide underhand pitching instruction for injury prevention.

Balance And Kinematic Swing Sequence In Older Female Golfers

Female golfers account for approximately 25% of the entire golfing population in the United States and 16% of female golfers are over the age of 60. While balance and golf swing kinematic sequence are frequently cited as important performance determinants, literature involving the older female golfer is limited. PURPOSE: To examine the balance profile (during specific dynamic tasks) and kinematic golf-swing pattern displayed in older female golfers. METHODS: Thirteen female golfers using a right-handed swing strategy (mean age ± SD, 67.5 ± 5.5) completed the Modified Clinical Test of Sensory Integration of Balance and the Rhythmic Weight Shift (RWS) protocols in order to collect balance data. A golf-swing kinematic assessment was also performed. Three recorded drives were used to analyze the swing and establish a dominant sequence. Balance outcome data were examined with reference to established age-matched normal values. Golf-swing kinematic sequence patterns were compared between those participants within (N=7; mean age ± SD, 66.1 ± 5.2) and outside of (N=6; mean age ± SD, 69 ± 5.9) normal Forward-Backward Directional Control (FBDCL). RESULTS: All participants displayed normal directional velocity values for the RWS assessment but only half demonstrated normal FBDCL. The kinematic sequence analysis revealed that 53.8% of all participants optimally initiated the downswing by leading with the pelvis. Golfers with normal FBDCL (mean % time on axis ± SD, 79.1 ± 5.5), were more likely (71.4%) to initiate a normal kinematic swing sequence compared to 33.3% of those with abnormal FBDCL (mean % time on axis ± SD, 64 ± 7). CONCLUSIONS: The results of this study suggest that this population of golfers may need to consider exercise or training programs designed to improve forward/backward dynamic balance control as a means to assist in optimizing the kinematic sequence and overall golf-swing performance.

Toward Hand-Dominated Activity Recognition Systems With Wristband-Interaction Behavior Analysis

The increasing usage of wearable devices for ambulatory monitoring and pervasive computing systems has given rise to the need of convenient and efficient activity recognition techniques. Hand-dominated activity recognition has great potential in understanding users’ gesture and providing context-aware computing services. This paper investigates the feasibility and applicability on the usage of wristband-interaction behavior for recognizing hand-dominated activities, with the advantage of great compliance and long wearing time. For each action, sensor data from wristband are analyzed to obtain kinematic sequences. The sequences are then depicted by statistics-, frequency-, and wavelet-domain features for providing accurate and fine-grained characterization of hand-dominated actions, and the correlation between the wristband-sensor features and the actions is analyzed. Classification techniques (Naive Bayes, nearest neighbor, neural network, support vector machine, and Random Forest) are applied to the feature space for performing hand-dominated activity recognition. Analyses are conducted using the data from 51 participants with a diversity in gender, age, weight, and height. Extensive experiments demonstrate the efficacy of the proposed approach, achieving a recognition rate of 97.29% and an ${F}$ -score above 0.94. Additional experiments on the effect of feature selection and wristband sampling rate are provided to further examine the effectiveness of our approach. Our data are publicly available.

Effects of pelvis-shoulders torsional separation style on kinematic sequence in golf driving

ABSTRACTThe golfer’s body (trunk/arms/club) can be modeled as an inclined axle-chain system and the rotations of its parts observed on the functional swing plane (FSP) can represent the actual angular motions closely. The purpose of this study was to investigate the effects of pelvis-shoulders torsional separation style on the kinematic sequences employed by the axle-chain system in golf driving. Seventy-four male skilled golfers (handicap ≤ 3) were assigned to five groups based on their shoulder girdle motion and X-factor stretch characteristics: Late Shoulder Acceleration, Large Downswing Stretch, Large Backswing Stretch, Medium Total Stretch, and Small Total Stretch. Swing trials were captured by an optical system and the hip-line, thorax, shoulder-line, upper-lever, club, and wrist angular positions/velocities were calculated on the FSP. Kinematic sequences were established based on the timings of the peak angular velocities (backswing and downswing sequences) and the backswing-to-downswing transition time points (transition sequence). The backswing and transition sequences were somewhat consistent across the groups, showing full or partial proximal-to-distal sequences with minor variations. The downswing sequence was inconsistent across the groups and the angular velocity peaks of the body segments were not significantly separated. Various swing characteristics associated with the separation styles influenced the motion sequences.

Baseball Pitchers’ Kinematic Sequences and Their Relationship to Elbow and Shoulder Torque Production

Objectives:Ball velocity is generated during the overhead baseball pitch via efficient force transmission up the kinetic chain, from the lower body up and outward to the throwing hand. The kinematic sequence, or the sequential timing pattern of peak angular velocities of body segments during a pitch, provides insight to segment position and motion control that drives the kinetic chain (Putnam CA, 1993). Previous publications report an ideal kinematic sequence (KS) where the timing of each body segment’s peak angular velocity occurs in a proximal-to-distal (PDS) pattern resulting in greater ball velocity and reduction in throwing arm injury risk (Fortenbaugh D, et.al, 2009). A recent study revealed that baseball pitchers perform a variety of KSs (Scarborough DM et.al, 2018). There is no known investigation of the relationship of kinematic sequences and throwing arm joint torques. The purpose of this study was to 1) identify the number of different KSs performed by each pitcher and 2) compare elbow valgus and shoulder external rotation (ER) and extension (Ext) torques between the 3 primary KSs performed during the fastball pitch.Methods:Fourteen collegiate baseball pitchers (20.57 ± 1.91 yr) underwent 3D biomechanical pitch analysis using 20 motion-capture Vicon MX™ cameras (360 Hz). A total of 119 fastball pitches with an average of 8.5 ± 2.71 pitches per player were analyzed. Elbow valgus and shoulder external rotation and extension torques were calculated. The timing of peak angular velocities for the pelvis, trunk, arm, forearm and hand body segments were recorded to generate each pitch’s KS. KSs were then divided into groups based on similarities to the ideal PDS pattern. ANCOVA statistical analyses were performed to compare joint torques across these KS groups with ball velocity as a covariate.Results:A total of 13 different KSs were observed across the 14 pitchers resulting in an average of 3 ± 1.41 different KSs per pitcher. Three different primary KS groups were identified: (1) PDS group: with a KS closest to the ideal PDS pattern (2) the Altered Distal Upper Extremity segment: with the forearm peaking after the hand (the most common group) and (3) Altered Proximal Upper Extremity segment order with the arm segment peaking after the hand (2nd most common). Across these three primary KS patterns, statistically significant differences were noted for elbow valgus torque [F(62,2) = 8.785, ɳ2 = .221, p < 0.00], shoulder external rotation (ER) torque [F(62,2) = 14.127, ɳ2 = .313, p < 0.00] and shoulder extension (Ext) torque [F(62,2) = 13.237, ɳ2 = .299, p < 0.00] (Figure 1).Conclusion:Our findings demonstrate that collegiate baseball pitchers performed an average of 3 different kinematic sequence patterns during fastball pitching. This is the first study to demonstrate a relationship between KSs and elbow and shoulder torque production. As anticipated, the PDS KSs produced the least torque across the elbow and shoulder joints. Alterations in Distal Upper Extremity KS was most common and generated the greatest shoulder Ext torques. Alterations in the Proximal Upper Extremity KS demonstrated the greatest elbow valgus and shoulder ER. Further study of the influence of kinematic sequence on joint torques in the baseball pitch may provide insight into pitching injuries and injury avoidance programs.

Determining kinematic order and relative age of faulting via flexural‐kinematic restoration: A case study in far western Nepal

AbstractForward modeled, balanced cross sections that account for the flexural response to thrust loading and erosional unloading can verify and refine the kinematic sequence of deformation in fold‐thrust belts as well as help assess the validity of a balanced cross section. Results from flexural‐kinematic reconstructions that indicate either the cross section, the kinematic order or both are invalid include: (a) a predicted final topography that is dramatically different from the actual topography; (b) large normal fault or thrust fault bounded synorogenic basins that are not present in the mapped geology; and/or (c) an exhumation history that is not consistent with provenance records in the basin or measured thermochronometers. Where detailed measured foreland basin sections exist, flexural‐kinematic modeling of fold‐thrust belt deformation, including out‐of‐sequence (OOS) faults can predict a foreland basin evolution that can be compared to measured data. The modeling process creates a “pseudostratigraphy” in the modeled foreland. The pseudostratigraphy and predicted provenance of each modeled stratigraphic increment can be directly compared to measured stratigraphic sections. We present a case study using two cross sections through the Himalaya of far western Nepal (Api and Simikot) to assess the validity of the section geometries and the resulting kinematic histories, displacement rates, flexural wave response and predicted provenance for both sections. Insights from combining the flexural‐kinematic models with existing stratigraphic data include: (a) Changing the order of proposed OOS and normal faults to earlier in the evolution of the fold‐thrust belt was necessary to reproduce the foreland provenance data. We argue that OOS thrust and normal faults in the Api section occurred between 11 and 4 Ma. (b) Published shortening estimates for the Simikot cross section are too high (&gt;50 km), resulting in unrealistic shortening rates up to 80 mm/yr between 25 and 20 Ma. (c) Flexural forward models with and without an additional sediment loading modeling step indicate that while sediment loading does not have a measurable effect on the magnitude and location of erosion within the fold‐thrust belt, it does have a small effect on accumulation rates and thus the predicted age of stratigraphic boundaries when compared to measured stratigraphic thicknesses and age. Thickness difference range from 0.2 to 0.5 km and can result in predicted age differences of ca. 1 Ma. Accounting for both flexural isostacy and erosion can eliminate unviable kinematic sequences and when combined with provenance data from measured stratigraphic sections, can provide insight into the order, age and rate of deformation.

Does The Kinematic Sequence Of A Curveball Pitch Vary Within Baseball Pitchers?

Does The Kinematic Sequence Of A Curveball Pitch Vary Within Baseball Pitchers?

Estimating Vocal Fold Contact Pressure from Raw Laryngeal High-Speed Videoendoscopy Using a Hertz Contact Model.

The development of trauma-induced lesions of the vocal folds (VFs) has been linked to a high collision pressure on the VF surface. However, there are no direct methods for the clinical assessment of VF collision, thus limiting the objective assessment of these disorders. In this study, we develop a video processing technique to directly quantify the mechanical impact of the VFs using solely laryngeal kinematic data. The technique is based on an edge tracking framework that estimates the kinematic sequence of each VF edge with a Kalman filter approach and a Hertzian impact model to predict the contact force during the collision. The proposed formulation overcomes several limitations of prior efforts since it uses a more relevant VF contact geometry, it does not require calibrated physical dimensions, it is normalized by the tissue properties, and it applies a correction factor for using a superior view only. The proposed approach is validated against numerical models, silicone vocal fold models, and prior studies. A case study with high-speed videoendoscopy recordings provides initial insights between the sound pressure level and contact pressure. Thus, the proposed method has a high potential in clinical practice and could also be adapted to operate with laryngeal stroboscopic systems.

Biomechanical analysis of the golf swing: methodological effect of angular velocity component on the identification of the kinematic sequence.

The golf swing is a complex whole-body motion for which a proximal-to-distal transfer of the segmental angular velocities from the pelvis to the club is believed to be optimal for maximizing the club head linear velocity. However, previous experimental results about such timing (or kinematic sequence) are contradictory. Nevertheless, methods that were used in these studies differed significantly, in particular, those regarding the component of the angular velocity vector selected for the identification of the kinematic sequence. Hence, the aim of this study was to investigate the effect of angular velocity vector component selection on the identified kinematic sequence. Thirteen golfers participated in this study and performed driver swings in a motion capture laboratory. Seven methods based on different component selection of segmental angular velocities (vector norm, component normal-to-sagittal, frontal, transversal and swing planes, segment longitudinal component and a method mixing longitudinal and swing plane components) were tested. Results showed the critical influence of the component chosen to identify the kinematic sequence with almost as many kinematic sequences as the number of tested methods for every golfer. One method seems to show the strongest correlation to performance but none of them can be assessed as a reference method for the identification of the golf swing kinematic sequence. Regarding the limited time lag between the different peak occurrences and the uncertainty sources of current materials, development of simulation studies would be more suitable to identify the optimal kinematic sequence for the golf swing.

Bus Driving Cycle Construct Based on Principal Component Analysis for Lanzhou City

The construction of city bus driving cycle is the key to improve traffic efficiency and transportation capacity. In this paper, the data acquisition parameter model is established by taking the Lanzhou city as an example. The data collected from the vehicle recorder are divided into several kinematics sequences. The eigenvalues of these sequences are investigated by principal component analysis and cluster analysis with SPSS tool. Based on the correlation coefficient of collected data from five typical bus lines for more than one month, three representative kinematic sequences are selected to construct the bus driving cycle for Lanzhou city. Experiments show that: 1) The bus driving cycle for Lanzhou city has the characteristics of less uniform time, low average speed and frequent acceleration and deceleration; 2) There exist large differences in bus driving characteristics between the European ECE15 driving cycle, commonly used in the China's urban roads and that of Lanzhou city.

Kinematic sequence patterns in the overhead baseball pitch

ABSTRACT Conceptually, an efficient baseball pitch demonstrates a proximal-to-distal transfer of segmental angular velocity. Such a timing pattern (or kinematic sequence) reduces stress on musculoskeletal structures of the throwing arm and maximises ball velocity. We evaluated the variability of kinematic sequences in 208 baseball pitches. 3D biomechanical pitch analyses were performed on 8–10 fastball pitches from 22 baseball pitchers (5 high school, 11 collegiate and 6 professional). The kinematic sequence patterns – time of peak angular velocity of five body segments: pelvis, trunk, arm, forearm and hand – were measured. None of the pitches analysed demonstrated an entirely proximal-to-distal kinematic sequence. Fourteen different kinematic sequence patterns were demonstrated, with the most prevalent sequence being pelvis → trunk → arm → hand → forearm. Fewer than 10% of the pitchers performed only one kinematic sequence pattern across the sampled pitches. The variability of the kinematic sequence was similar in high-school pitchers and professionals. Previous studies report that deviation from the proximal-to-distal kinematic sequence is associated with increased injury risk. As a method of evaluating the efficient transfer of energy to the hand, the kinematic sequence may provide insight to injury risk in the future. The ideal kinematic sequence and ideal variability of the sequence when throwing have yet to be determined.

Changes in golf swing kinematic sequence after 12 weeks of reactive neuromuscular training using inertia overloading

[Purpose] We examined the influence of reactive neuromuscular training (RNT) on golf swing coordination. RNT aims to induce proper coordinative movement by exaggerating the performer’s mistakes. Therefore, we applied RNT using inertia overloading to golfers who have problems with kinematic sequence during a golf swing. [Methods] To examine the effect of 12 weeks of RNT on golf swing coordination, we employed a ball tracking system (launch monitor) and motion analysis system (inertia sensors) were taken on four consecutive periods (pre-test and post-tests 4, 8, and 13 weeks later). Thirty Korean male cadets were divided into three groups based on inertial loading and practiced 7-iron golf swings combined with specific group tasks twice per week. [Results] At pre-test, most participants reached maximal angular velocity near the impact timing (95-100%). However, the deceleration timing of the maximum angular velocity of the proximal segments gradually moved toward mid-downswing as the training sessions proceeded, with the RNT group ultimately outperforming the two control groups. Additionally, the RNT group showed a significantly higher maximum angular velocity in the thorax and wrist. [Conclusion] Our results suggest that RNT can be sufficient to elicit and effective whole-body coordination pattern. Considerable follow-up research is needed on the use of RNT for various sports tasks and the effects of expertise on RNT results.

Palaeostress magnitudes in the Khao Khwang fold-thrust belt, new insights into the tectonic evolution of the Indosinian orogeny in central Thailand

Using the Khao Khwang fold–thrust belt in central Thailand as case study, we handled data from calcite twinning analysis in order to propose the quantification of the effective principal palaeostresses magnitudes since the onset of the early stages of the Indosinian orogeny. We also combined the differential stress estimates from mechanically-induced calcite twins with geochronological data in order to constrain the timing of the palaeoburial depth and subsequent uplift by folding within the Khao Khwang fold–thrust belt. The proposed mechanical scenario is based on the time-constrained kinematic sequence of fracturing, faulting, and folding in the strata of the carbonate formations of the Saraburi Group. Cross-checking the data on the palaeostress orientations, regimes, and differential stress magnitudes with rock mechanics analysis; we provided data on the principal stress magnitudes for each tectonic stage that developed during the Indosinian orogeny. Further, 40Ar/39Ar and U-Pb geochronological data allowed to place reliable constraints on the amount and rate of vertical uplift of the carbonate formations of the Saraburi Group.

Baleen Hydrodynamics and Morphology of Cross-Flow Filtration in Balaenid Whale Suspension Feeding.

The traditional view of mysticete feeding involves static baleen directly sieving particles from seawater using a simple, dead-end flow-through filtration mechanism. Flow tank experiments on bowhead (Balaena mysticetus) baleen indicate the long-standing model of dead-end filtration, at least in balaenid (bowhead and right) whales, is not merely simplistic but wrong. To recreate continuous intraoral flow, sections of baleen were tested in a flume through which water and buoyant particles circulated with variable flow velocity. Kinematic sequences were analyzed to investigate movement and capture of particles by baleen plates and fringes. Results indicate that very few particles flow directly through the baleen rack; instead much water flows anteroposteriorly along the interior (lingual) side of the rack, allowing items to be carried posteriorly and accumulate at the posterior of the mouth where they might readily be swallowed. Since water flows mainly parallel to rather than directly through the filter, the cross-flow mechanism significantly reduces entrapment and tangling of minute items in baleen fringes, obviating the need to clean the filter. The absence of copepods or other prey found trapped in the baleen of necropsied right and bowhead whales supports this hypothesis. Reduced through-baleen flow was observed with and without boundaries modeling the tongue and lips, indicating that baleen itself is the main if not sole agent of crossflow. Preliminary investigation of baleen from balaenopterid whales that use intermittent filter feeding suggests that although the biomechanics and hydrodynamics of oral flow differ, cross-flow filtration may occur to some degree in all mysticetes.

Breaststroke swimmers moderate internal work increases toward the highest stroke frequencies

A model to predict the mechanical internal work of breaststroke swimming was designed. It allowed us to explore the frequency–internal work relationship in aquatic locomotion. Its accuracy was checked against internal work values calculated from kinematic sequences of eight participants swimming at three different self-chosen paces. Model predictions closely matched experimental data (0.58±0.07 vs 0.59±0.05Jkg−1m−1; t(23)=−0.30, P=0.77), which was reflected in a slope of the major axis regression between measured and predicted total internal work whose 95% confidence intervals included the value of 1 (β=0.84, [0.61, 1.07], N=24). The model shed light on swimmers ability to moderate the increase in internal work at high stroke frequencies. This strategy of energy minimization has never been observed before in humans, but is present in quadrupedal and octopedal animal locomotion. This was achieved through a reduced angular excursion of the heaviest segments (7.2±2.9° and 3.6±1.5° for the thighs and trunk, respectively, P<0.05) in favor of the lightest ones (8.8±2.3° and 7.4±1.0° for the shanks and forearms, respectively, P<0.05). A deeper understanding of the energy flow between the body segments and the environment is required to ascertain the possible dependency between internal and external work. This will prove essential to better understand swimming mechanical cost determinants and power generation in aquatic movements.

Research on Driving Cycle of Long-distance Passenger Vehicles Based on Principal Component Analysis and Cluster Algorithm

In order to get the vehicle' actual driving mode in a different road conditions, the driving data is divided into kinematic sequence for analysis of driving cycle. On the basis of kinematics fragments, the characteristic parameters of kinematic sequence are carried out with the principal component analysis. Then driving cycle are synthesized based on dynamic clustering algorithm analysis to get the vehicle' driving state in different road conditions.

Cam Drive Step Mechanism of a Quadruped Robot

Bionic quadruped robots received considerable worldwide research attention. For a quadruped robot walking with steady paces on a flat terrain, using a cam drive control mechanism instead of servomotors provides theoretical and practical benefits as it reduces the system weight, cost, and control complexities; thus it may be more cost beneficial for some recreational or household applications. This study explores the robot step mechanism including the leg and cam drive control systems based on studying the bone structure and the kinematic step sequences of dog. The design requirements for the cam drive robot legs have been raised, and the mechanical principles of the leg operating mechanism as well as the control parameters have been analyzed. A cam drive control system was constructed using three cams to control each leg. Finally, a four-leg demo robot was manufactured for experiments and it showed stable walking patterns on a flat floor.