The biomechanical characteristics of high-performance endurance running

The biomechanical profile of high-level endurance runners may represent a useful model that could be used for developing training programmes designed to improve running style. This study, therefore, sought to compare the biomechanical characteristics of high-performance and recreational runners. Kinematic and kinetic measurements were taken during overground running from a cohort of 14 high-performance (8 male) and 14 recreational (8 male) runners, at four speeds ranging from 3.3 to 5.6 m s−1. Two-way ANOVA analysis was then used to explore group and speed effects and principal component analysis used to explore the interdependence of the tested variables. The data showed the high-performance runners to have a gait style characterised by an increased vertical velocity of the centre of mass and a flight time that was 11% longer than the recreational group. The high-performance group were also observed to adopt a forefoot strike pattern, to contact the ground with their foot closer to their body and to have a larger ankle moment. Importantly, although observed group differences were mostly independent of speed, the tested variables showed a high degree of interdependence suggesting an underlying unitary phenomenon. This is the first study to compare high-performance and recreational runners across a full range of kinematic and kinetic variables. The results suggest that high-performance runners maintain stride length with a prolonged aerial phase, rather than by landing with a more extended knee. These findings motivate future intervention studies that should investigate whether recreational runners could benefit from instruction to decrease shank inclination at foot contact

A marker set for measuring the kinematics of the lumbar spine and thoracic spine during running : a technical note

A protocol for tracking the motion of the lumbar spine, which uses seven skin mounted markers, has been adopted in previous studies investigating running. However, this configuration of can be difficult to track with passive motion capture systems. This study therefore investigated whether a four-marker configuration could accurately reproduce the pose of the lumbar spine obtained using the seven-marker configuration. The study also investigated two methods of tracking the thorax. The first method consisted of markers attached to the sterum and the second used two markers placed bilaterally over the acromioclavicular joints and another on the posterior thoracic spine. Kinematic data was collect for n=15 male subjects and the pose, calculated using the different tracking configurations, compared for both the lumbar spine and thoracic spine. The results demonstrated a good match between two lumbar tracking marker sets. However, there was considerable difference between the two thoracic markers sets which was likely due to movement of the arms influencing the pose of the thorax. We therefore recommend the use of four makers to track the motion of the lumbar spine and a rigid plate, mounted at the top of the sternum, to track motion of the thoracic spine during running

Reproducibility of kinematic measures of the thoracic spine, lumbar spine and pelvis during fast running

This study evaluated the reproducibility of the angular rotations of the thoracic spine, lumbar, spine, pelvis and lower extremity during running. In addition, the study compared kinematic, reproducibility between two methods for calculating kinematic trajectories: a six degrees of freedom, (6DOF) approach and a global optimisation (GO) approach. With the first approach segments were, treated independently, however with GO approach joint constraints were imposed to stop translation, of adjacent segments. A total of 12 athletes were tested on two separate days whilst running over, ground at a speed of 5.6ms-1. The results demonstrated good between-day reproducibility for most, kinematic parameters in the frontal and transverse planes with typical angular errors of 1.4-3°., Acceptable repeatability was also found in the sagittal plane. However, in this plane, although, kinematic waveform shape was preserved between testing session, there were sometimes shifts in, curve offset which lead to slightly higher angular errors, typically ranging from 1.9-3.5°. In general, the, results demonstrated similar levels of reproducibility for both computational approaches (6DOF and, GO) and therefore suggest that GO may not lead to improved kinematic reproducibility during running

Drowsiness Detection System in Real Time Based on Behavioral Characteristics of Driver using Machine Learning Approach

The process of determining if a person, generally a driver, is becoming sleepy or drowsy while performing a task such as driving is known as drowsiness detection. It is a necessary system for detecting and alerting drivers to their tiredness, which might impair their driving ability and lead to accidents. The project aims to create a reliable and efficient system capable of real-time detection of drowsiness using OpenCV, Dlib, and facial landmark detection technologies. The project's results show that the sleepiness detection method can accurately and precisely identify tiredness in real time. The technology is less intrusive and more economical than conventional sleepiness detection techniques. The system is based on a 68 facial landmark detector, which is a highly trained and effective detector capable of recognizing human face points. The detector aids in assessing whether the driver's eyes are closed or open.  The system analyses the data collected by the detector using machine learning methods to discover patterns associated with drowsiness. When drowsiness is detected, the system incorporates a warning mechanism, such as an alarm or a vibration in the steering wheel, to notify the driver. A variety of studies with different drivers and driving conditions were used to evaluate the performance of the real-time driver drowsiness detection system. The results show that the technology can detect tiredness properly and deliver timely warnings to the driver. This method can assist in preventing drowsy driving incidents, enhancing road safety, and saving lives. The results indicated that the algorithm had an average accuracy rate of 94% for identifying tiredness in drivers

A 10% increase in step rate improves running kinematics and clinical outcomes in runners with patellofemoral pain at 4 weeks and 3 months

Background: Aberrant frontal plane hip and pelvis kinematics have been frequently observed in runners with patellofemoral pain (PFP). Gait retaining interventions have been shown to improve running kinematics and may therefore be beneficial in runners with PFP. Purpose: the aim of this study was to investigate whether a 10% increase in running step rate influences frontal plane kinematics of the hip and pelvis, as well as clinical outcomes in runners with PFP. Study Design: Case Series Methods: Runners with PFP underwent a 3D gait analysis to confirm the presence of aberrant frontal plane hip and pelvis kinematics at baseline. Twelve participants with frontal plane hip and pelvis kinematics one standard deviation above a reference database, were invited to participate in the gait retraining intervention. Running kinematics along with clinical outcomes of pain and functional measures were recorded at baseline, 4 weeks following retraining and 3-months. Gait retraining consisted of a single session where step rate was increased by 10% using an audible metronome. Participants were asked to continue their normal running while self-monitoring their step rate using a global positioning system watch and audible metronome. Results: Following gait retraining significant improvements in running kinematics and clinical outcomes were observed at 4 week and 3-month follow up. Repeated measures ANOVA with post hoc Bonferroni (p <0.016) showed significant reductions in peak contralateral pelvic drop (Mean Difference [MD], 3.12⁰; 95% Confidence Interval [CI], 1.88⁰, 4.37⁰), hip adduction (MD, 3.99⁰; 95% CI, 2.01⁰, 5.96⁰) and knee flexion (MD, 4.09⁰; 95% CI, 0.04⁰, 8.15⁰), as well as significant increases in self-reported weekly running volume (MD, -13.78km; 95% CI, -22.93km, -4.62km) and longest run pain free (MD, -6.84km; 95% CI, -10.62km, -3.05km). Friedman test with post hoc Wilcoxon signed-rank showed significant improvements in Numerical Rating Scale for worst pain in the past week and Lower Extremity Functional Scale. Conclusion: A single session of gait retraining using a 10% increase in step rate results in significant improvements in running kinematics, pain and function in runners with PFP. These improvements were maintained at 3-month follow up. It is important to assess for aberrant running kinematics at baseline to ensure gait interventions are targeted appropriately. Clinical Relevance: Step rate modification is a simple method of gait retraining that can be easily integrated into clinical practice and running outside of a laboratory setting

The association between running kinematics and common overuse injuries in runners : implications for injury and rehabilitation

Background: Running related injuries are influenced by a complex interaction between multiple factors. Running kinematic patterns represent one such factor which will influence the load applied to musculoskeletal structures during each foot contact of a run. When combined with an increase in external training load, a cumulative tissue load may result that exceeds tissue capacity, resulting in injury development. Aim: This thesis aimed to identify kinematic parameters associated with common running related injuries, explore whether such factors are influenced by training load exposure and investigate whether gait retraining, aimed at improving to running kinematics, may represent a clinically effective intervention. Methods: A narrative literature review was conducted to identify gaps within the literature and formulate specific research questions. An initial study was performed to investigate the between day repeatability and quantify the standard error of measurement for discrete kinematic parameters during running. A case control study of 108 runners was then undertaken to investigate whether similar kinematic parameters are associated with multiple different common running related injuries. Following identification of kinematic parameters associated with running injuries, a cross sectional study investigated whether kinematic parameters associated with injury are associated with training load exposure. Finally, a case series study investigated whether gait retraining, in the form of a step rate intervention, improves running kinematics and clinical outcomes amongst a group of 12 injured runners with patellofemoral pain. Findings: The repeatability study demonstrated good to excellent repeatability with low measurement errors for several kinematic parameters during treadmill running. The second study found several kinematic parameters to be associated with multiple different running related injuries, including increased contralateral pelvic drop, hip adduction and forward trunk lean, as well as reduced knee flexion and increased ankle dorsiflexion at initial contact. Within this study, a logistic regression analysis found peak contralateral pelvic drop to be the kinematic parameter most strongly associated with common running injuries. Data from this study was used to set a critical threshold for peak contralateral pelvic drop, above which runners were deemed more likely to be at risk of injury. Building on this idea, the third study, highlighted an association between training load exposure and running kinematics. Specifically, amongst injury-free high-mileage runners, a significantly lower proportion of runners exhibited “high-risk” kinematics than in a group of injury-free low-mileage runners. Finally, the case series study found a single session of gait retraining, via a 10% increase in step rate, resulted in significant reductions in peak contralateral pelvic drop, hip adduction and knee flexion, as well as significant improvements in clinical and functional outcomes amongst runners with patellofemoral pain. Implications: Several kinematic parameters appear to be associated with multiple different running related injuries, suggesting similar kinematic patterns may increase tissue load on multiple different anatomical locations. Interestingly, there appears to be a complex interaction between kinematics and training load exposure highlighting that kinematics alone may be unlikely to explain injury development. In such instances where runners have become injured and possess kinematic parameters which increase tissue load, increasing step rate appears to be an effective gait intervention which can be easily integrated into clinical practise and a runner’s normal routine

Are the arms and head required to accurately estimate centre of mass motion during running?

Accurate measurement of centre of mass (CoM) motion can provide valuable insight into the biomechanics of human running. However, full-body kinematic measurement protocols can be time consuming and difficult to implement. Therefore, this study was performed to understand whether CoM motion during running could be estimated from a model incorporating only lower extremity, pelvic and trunk segments. Full-body kinematic data was collected whilst (n = 12) participants ran on a treadmill at two speeds (3.1 and 3.9 ms−1). CoM trajectories from a full-body model (16-segments) were compared to those estimated from a reduced model (excluding the head and arms). The data showed that, provided an offset was included, it was possible to accurately estimate CoM trajectory in both the anterior-posterior and vertical direction, with root mean square errors of 5 mm in both directions and close matches in waveform similarity (r = 0.975-1.000). However, in the ML direction, there was a considerable difference in the CoM trajectories of the two models (r = 0.774–0.767). This finding suggests that a full-body model is required if CoM motions are to be measured in the ML direction. The mismatch between the reduced and full-body model highlights the important contribution of the arms to CoM motion in the ML direction. We suggest that this control strategy, of using the arms rather than the heavier trunk segments to generate CoM motion, may lead to less variability in CoM motion in the ML direction and subsequently less variability in step width during human running

Is there a pathological gait associated with common soft tissue running injuries?

Background: Previous research has demonstrated clear associations between specific running injuries and patterns of lower limb kinematics. However, there has been minimal research investigating whether the same kinematic patterns could underlie multiple different soft tissue running injuries. If they do, such kinematic patterns could be considered global contributors to running injury. Hypothesis: Injured runners will demonstrate differences in running kinematics when compared to injury free controls. These kinematic patterns will be consistent amongst injury subgroups. Study Design: Case- Control Study Methods: We studied 72 injured runners and 36 healthy controls. The injured group contained four subgroups of runners with either patellofemoral pain, iliotibial band syndrome, medial tibial stress syndrome or Achilles tendinopathy (n = 18 each). Three-dimensional running kinematics were compared between injured and healthy runners and then between the four injured subgroups. A logistic regression model was used to determine which parameters could be used to identify injured runners. Results: The injured runners demonstrated greater contralateral pelvic drop and forward trunk lean at mid-stance and a more extended knee and dorsiflexed ankle at initial contact. The subgroup ANOVA found these kinematic patterns were consistent across each of the four injury subgroups. Contralateral pelvic drop was found to be the most important variable predicting classification of participants as healthy/injured. Importantly, for every 1° increase in pelvic drop there was an 80% increase in the odds of being classified injured. Conclusion: This study identified a number of global kinematic contributors to common running injuries. In particular, we found injured runners to run with greater peak contralateral pelvic drop and trunk forward lean, as well as an extended knee and dorsiflexed ankle at initial contact. Contralateral pelvic drop appears to be the variable most strongly associated with common running related injuries. Clinical Relevance: The identified kinematic patterns may prove beneficial for clinicians when assessing for biomechanical contributors to running injuries

Cellular electrophysiologic responses of isolated neonatal and adult cardiac fibers to d-sotalol

AbstractThe short-term cellular electrophysiologic actions of d-sotalol on isolated neonatal and adult canine ventricular myocardium and Purkinje fibers were evaluated using standard microelectrode techniques. d-Sotalol, 10−6to 10−4M, had no effects on action potential amplitude, maximal diastolic potential or action potential upstroke velocity (Vmax) in any neonatal or adult preparation. In five adult myocardial preparations, d-sotalol produced concentration-dependent increases in action potential duration at 50% (APD50) and 90% (APD90) repolarization and effective refractory period. In six neonatal myocardial preparations, d-sotalol produced a biphasic response; APD50, APD90and effective refractory period decreased at 10−6and 10−5M. At 10−4M, these values increased significantly but to a lesser extent compared with values in adults.In seven adult Purkinje fibers, d-Sotalol significantly increased APD50, APD90and effective refractory period in a concentration-dependent manner. All six neonatal Purkinje fibers responded in a biphasic manner, with values for APD50, APD90and effective refractory period being less than control at 10−6Mand near control values at 10−5M. At 10−4M, these variables were significantly increased, but to a lesser extent than in audlt preparations. Our data confirm the typical class III effects of d-sotalol in adult cardiac tissues. The shortening of repolarization and refractoriness at lower drug concentrations in developing cardiac tissues may relate to age-dependent differences in cellular ionic function and basic electrophysiology