Differences In Joint Kinematics Research Articles

Does cranial cruciate ligament repair by tibial plateau leveling osteotomy surgery restore dog’s natural kinematics? – A case series

Tibial plateau leveling osteotomy (TPLO) serves as an effective method of functional stabilization for treating cranial cruciate ligament (CrCL) deficiency. It is not clear if TPLO could restore the natural kinematics of the stifle, hip, and tarsal joints of the affected limb during walking. The hind limb motion between TPLO cases and control groups in eight adult dogs (4 French Bulldogs and 4 Pit Bull Terrier) was recorded by a motion capture system. Three-dimensional (3D) angular motions of the hip, stifle, and tarsal joints—including flexion-extension, abduction-adduction, and rotations—were computed and compared. Significant differences in joint kinematics were observed between TPLO cases and controls. In Case 1, the TPLO case in the French Bulldog showed differences in hip, stifle, and tarsal flexion-extension, abduction-adduction, and internal-external rotation. Asymmetries between affected and unaffected limbs were also detected in hip and stifle motions (up to 43° in some cases). Similar patterns of differences were found in Pit Bull Terriers Case 2 and Case 3, with significant variations in hip, stifle, and tarsal movements. Case 3 did not show hip asymmetries, but notable stifle and tarsal asymmetries were observed. The general daily activity performance for French Bulldogs and Pit Bull Terriers that underwent TPLO procedures was positive. The general daily restricted activity performance for the French Bulldog and Pit Bull Terriers that underwent TPLO procedures was positive. Our findings suggested that natural hind limb kinematics during gait was not restored in TPLO hind limb cases in both breeds.

The relationship between executed cut angle and speed with lower extremity joint angles during unanticipated side-step cutting in soccer players

BackgroundCertain movements patterns have been indicated in knee injuries during cutting while running tasks. Differences in the executed cut angle (ECA) could partially account for group differences in joint kinematics previously observed, including sex differences. Research QuestionAre there relationships between joint angles with entry speed and ECA during side-step cutting in soccer players? MethodsThis cross-sectional study recruited 21 (10 females) soccer players. Participants completed 45o unanticipated side-step cuts in both directions. Kinematic data were captured with a 12 camera motion capture system with 46 reflective markers placed on the participants. Peak joint angles were determined during the stance phase of the cutting task. Entry speed and ECA were determined from pelvis markers. Hierarchical linear models examined relationships between angles, entry speed, and ECA, after accounting for age, sex, and leg preference. Regression coefficients with 95% confidence intervals were reported and statistical significance (p<0.05) were examined using the Wald statistic. ResultsThe mean ECA (24.6o) was lower than the intended 45o angle. Peak joint angles were significantly related to both ECA and entry speed. Specifically, an increase in ECA by 10o (i.e., sharper cuts) would increase hip internal rotation and ankle plantarflexion by 1.8 to 2.1o, and decrease hip adduction, knee abduction and ankle eversion by 1.3 to 2.4o. Faster entry speeds by 0.5m/s would increase hip flexion, hip internal rotation and knee extension angles by 1.8 to 3.8o, and decrease knee abduction by 2.6o. SignificanceStudies evaluating cutting while running should consider ECA and entry speed in their design. Potential differences could confound between-group comparisons of joint angles, including when comparing sexes, and impact interpretations of injury risk.

Biomechanical analysis of the snatch technique for elite and varsity weightlifters

Understanding the importance of movement asymmetries and variations in technique proficiency across different level of weightlifters is crucial. The purpose of this study was to examine differences in joint kinematics, muscle activation, and barbell parameters between elite and varsity weightlifters during the snatch utilizing integrated 3D motion capture and EMG systems. In addition, it analyzes symmetries in joint kinematics and muscle activation in both groups. Ten female participants, comprising 5 elite and 5 varsity weightlifters, along with thirteen male participants, consisting of 6 elite and 7 varsity weightlifters during snatch were measured. Several asymmetries in posture and muscle activation were identified in both elite and varsity weightlifters. In addition, elite weightlifters exhibited significantly more flexed knees than varsity counterparts (p < 0.05) at the conclusion of the second pull and at the highest position of the barbell. Furthermore, significantly lower activity in gluteus maximus was detected in elite weightlifter at the highest point of the barbell than in the varsity groups (p < 0.05). Moreover, elite males achieved a lower maximum height for the barbell compared to varsity males (p = 0.006). Furthermore, elite females demonstrated less horizontal displacement (D2x) (p = 0.005) than varsity counterparts. Varsity women presented significantly lower horizontal velocity (p = 0.003) at the conclusion of the second pull than varsity counterparts. Despite several asymmetries detected, those may not be critical factors in achieving a successful snatch lift, given that all weightlifters successfully completed the lift. However, variations in posture and muscle activation may still be associated with improvements in technique proficiency across different levels of weightlifters.

Stroke walking and balance characteristics via principal component analysis

Balance impairment is associated gait dysfunction with several quantitative spatiotemporal gait parameters in patients with stroke. However, the link between balance impairments and joint kinematics during walking remains unclear. Clinical assessments and gait measurements using motion analysis system was conducted in 44 stroke patients. This study utilised principal component analysis to identify key joint kinematics characteristics of patients with stroke during walking using average joint angles of pelvis and bilateral lower limbs in every gait-cycle percentile related to balance impairments. Reconstructed kinematics showed the differences in joint kinematics in both paretic and nonparetic lower limbs that can be distinguished by balance impairment, particularly in the sagittal planes during swing phase. The impaired balance group exhibited greater joint variability in both the paretic and nonparetic limbs in the sagittal plane during entire gait phase and during terminal swing phase respectively compared with those with high balance scores. This study provides a more comprehensive understanding of stroke hemiparesis gait patterns and suggests considering both nonparetic and paretic limb function, as well as bilateral coordination in clinical practice. Principal component analysis can be a useful assessment tool to distinguish differences in balance impairment and dynamic symmetry during gait in patients with stroke.

Curved non-motorized treadmills do not biomechanically replicate overground running better than motorized treadmills

ABSTRACT The purpose of this study was to determine if curved non-motorized treadmills can reproduce overground running better than motorized treadmills by analysing the differences in joint kinematics (hip, knee, and ankle) using SPM. Nineteen recreational runners completed three randomized running tests on these surfaces. Kinematic data from the hip, knee, and ankle joints were collected. Two-tailed SPM t-tests were performed to analyse time-continuous gait cycles in three anatomical planes of each joint. Higher within-subject variability was observed in the frontal and transverse planes during curved non-motorized treadmill running. SPM analysis showed more significant differences (p < 0.05) between curved non-motorized treadmill and overground than between motorized treadmill and overground, mainly in knee (from 12% to 30% and 93% to 99% of the gait cycle) and ankle (from 19% to 23% of the gait cycle) in the sagittal plane. Therefore, running on curved non-motorized treadmills is more biomechanically different compared to overground than motorized treadmills, and might not be the best strategy to replicate overground running in terms of joint kinematics during highly controlled research studies. However, they could be an interesting tool in rehabilitation or training environments since the changes observed in joint kinematics were likely not functionally relevant.

Whole-body passive heating at moderate hyperthermic state impairs static and dynamic balance in healthy females

BackgroundWhether static and dynamic balances can be impaired with increasing core temperature in female participants remains unknown. PurposeWe tested the hypothesis that static and dynamic balances can be further impaired with systematic increases of core temperature by Δ1 °C and Δ 2 °C using whole-body passive heating. MethodEighteen female participants underwent a control trial (Con) and two progressive passive heating trials with Δ 1 °C and Δ 2 °C increase of oral temperature (TOral) using 45 °C water bath. In each trial, we assessed static balance with both eye open and closed and assessed dynamic balance using obstacle crossing at 10 %, 20 % and 30 % of the participant’s leg length. ResultsStatic balance was not different between Con and Δ1 °C but was different between Δ1 °C and Δ 2 °C in an eye closed condition. Furthermore, Δ 2 °C greatly impaired both static and dynamic balances when compared to Con. The joint angles and toe clearance increased while leading heel-obstacle distance decreased during crossing obstacles at the height of 20 % and 30 % leg length with leading limbs in the Δ2 °C compared to Δ 1 °C and Con (All P < 0.05). However, no differences in joint kinematics and toe clearance with trailing limbs were observed (All P > 0.05). ConclusionIn female participants, static and dynamic balances only became impaired when TOral increased 2 °C from baseline.

Kinematic Comparison Between Walking and Jogging in The Lower Limbs Joints

Background Walking and jogging are considered two of the most important movements in human daily life. However, no previous studies have been conducted comparing the kinematics between these two movements. Research questions Are there any differences in joint kinematics of the lower limbs when walking and jogging? Methods Thirteen healthy males participated in this study with a mean age of 31.6 years. A motion capture system was used to collect walking and jogging movements in the lower limbs. The joint angles in hip, knee and ankle were compared between two movements. Statistical method was the repeated measurement of general linear model. Results The main finding was a significant difference between walking and jogging in the hip and ankle in sagittal plane in the knee in the transverse plane. During the entire gait cycle, the hip max extension in walking were roughly 9 deg larger than in jogging, but hip max flexion in walking were roughly 4 deg smaller than in jogging; as whole in the sagittal plane, the range of motion in the hip was larger in walking than in jogging by roughly 12%. Knee angles in the transverse plane were significantly greater in jogging than in walking by roughly 6 deg or 26% while similar in the sagittal plane. The ankle had larger range of motion in jogging than in walking by roughly 10 deg or 22% in the sagittal plane. Significance The study results demonstrate that jogging has not increased hip range of motion in the sagittal plane, but increased knee rotation in transverse plane largely in compared with walking. Moreover, jogging required greater flexibility at the ankle. The findings indicate that the protection of injury needs to pay more attention to the knee and ankle.

A Biomechanical Comparison between Squatbar® and Olympic Barbell

When performing the traditional barbell back squat, athletes may experience discomfort in the shoulders or be limited by shoulder mobility. The Squatbar® is a barbell designed to be ergonomic to the shoulders but has never, in the scientific literature, been compared to the traditional Olympic barbell. Thus, the current study investigated kinematics, kinetics, and myoelectric activity (EMG) between the Squatbar® barbell and the Olympic barbell when performing a one-repetition maximum (1-RM) back squat. Twelve strength-trained men (body mass: 83.5 ± 7.8 kg, age: 27.3 ± 3.8 years, height: 180.3 ± 6.7 cm) performed a 1-RM squat with both the Olympic and Squatbar® barbells. The paired samples t-test revealed significantly more weight was lifted with the Olympic barbell compared to the Squatbar® barbell (148 ± 21 kg vs. 144.5 ± 20 kg) and was accompanied by greater shoulder external rotation (74 ± 7.5° vs. 59.6 ± 9.2°). No differences in joint kinematics of the lower limbs, kinetics, or EMG were observed between the two barbells. The results of the current study indicate the Squatbar® to be a suitable substitution for the Olympic barbell for athletes with reduced shoulder mobility when performing the squat. It was concluded that the Squatbar® induces similar kinetics, kinematics, and EMG when compared to the Olympic barbell, except for reducing external rotation of the shoulder.

Anteromedialization Tibial Tubercle Osteotomy Improves Patellar Contact Forces: A Cadaveric Model of Patellofemoral Dysplasia

Background: Patellofemoral (PF) dysplasia is common in patients with recurrent patellar instability. Tibial tubercle osteotomy (TTO) is performed with goals of correcting patellar maltracking and redistributing contact forces across the PF joint. The biomechanical effects of TTO in the setting of PF dysplasia have not been quantified. Purpose/Hypothesis: To quantify patellar contact mechanics and kinematics after TTO in the setting of PF dysplasia. We hypothesized that a simulated anteromedialization (AMZ) TTO would improve PF contact mechanics as compared with a pure medialization TTO. Study Design: Controlled laboratory study. Methods: PF dysplasia with Dejour type D classification was simulated in 7 cadaveric knees by replacing the native patellar and trochlear surfaces with synthetic polymeric patellar and trochlear implants. On each specimen, a flat TTO was fixed in 3 distinct positions simulating a pathologic lateralized tubercle (pathologic condition), a medialized tubercle (Elmslie Trillat), and an AMZ tubercle. The sum of forces acting on the medial and lateral patellar facet and patellar kinematics was computed for each knee for each condition from 0° to 70° of flexion at 10° increments. Results: Relative to the pathologic condition, AMZ TTO decreased contact forces across the lateral facet (20°-50° and 70° of flexion). Relative to the pathologic condition, Elmslie Trillat TTO had no effect on contact forces on either compartment. Relative to the Elmslie Trillat TTO, the AMZ TTO had significantly decreased contact forces across the medial facet (at 40°, 60°, and 70° of flexion). No significant differences in joint kinematics occurred across any groups. Conclusion: Of all groups studied, AMZ TTO resulted in significantly decreased patellar contact forces in simulated dysplastic PF joints. AMZ may be considered in certain patients with PF dysplasia to avoid medial compartment PF chondral overload. Clinical Relevance: PF dysplasia is common in patients with recurrent patellar instability who warrant surgical intervention to prevent subsequent recurrence. Numerous interventions to treat this condition, including various TTOs, have been proposed without a clear consensus. This cadaveric biomechanical study demonstrates that AMZ TTO resulted in more favorable PF contact mechanics than Elmslie Trillat TTO in a model representing PF dysplasia. AMZ TTO may be considered for patients in the setting of recurrent instability with PF dysplasia to avoid cartilage overload on the medial compartment of the PF joint.

How Do Joint Kinematics and Kinetics Change When Walking Overground with Added Mass on the Lower Body?

Lower-limb exoskeletons, regardless of their control strategies, have been shown to alter a user's gait just by the exoskeleton's own mass and inertia. The characterization of these differences in joint kinematics and kinetics under exoskeleton-like added mass is important for the design of such devices and their control strategies. In this study, 19 young, healthy participants walked overground at self-selected speeds with six added mass conditions and one zero-added-mass condition. The added mass conditions included +2/+4 lb on each shank or thigh or +8/+16 lb on the pelvis. OpenSim-derived lower-limb sagittal-plane kinematics and kinetics were evaluated statistically with both peak analysis and statistical parametric mapping (SPM). The results showed that adding smaller masses (+2/+8 lb) altered some kinematic and kinetic peaks but did not result in many changes across the regions of the gait cycle identified by SPM. In contrast, adding larger masses (+4/+16 lb) showed significant changes within both the peak and SPM analyses. In general, adding larger masses led to kinematic differences at the ankle and knee during early swing, and at the hip throughout the gait cycle, as well as kinetic differences at the ankle during stance. Future exoskeleton designs may implement these characterizations to inform exoskeleton hardware structure and cooperative control strategies.

Kinematics and paraspinal muscle activation patterns during walking differ between patients with lumbar spinal stenosis and controls

BackgroundThe narrowing of the spinal canal due to degenerative processes may lead to symptomatic lumbar spinal stenosis (sLSS) and impairments in the patients’ gait. Changes in lower extremity joint kinematics and trunk flexion angles have been reported, yet less is known about muscle activation patterns of paraspinal and gluteal muscles in patients with sLSS compared to healthy participants. Research questionDo muscle activation patterns together with sagittal joint kinematics differ between patients with sLSS and healthy controls and do these differences—quantified using gait scores—correlate with clinical scores? MethodsIn 20 patients with sLSS scheduled for surgery and 19 healthy participants, gait was assessed using seven inertial sensors and muscle activation of gluteus medius, erector spinae and multifidus using wireless surface electromyography (EMG). Differences in joint kinematics and EMG patterns were assessed using statistical parametric mapping with non-parametric independent sample t tests (P < 0.05). Gait scores that describe the overall deviation in joint angles (mGPS) and muscle activation patterns (EMG-Profile Score) were calculated as root mean square distances between patients and healthy participants and their associations with clinical scores (pain, Oswestry Disability Score (ODI)) were analyzed using Spearman’s correlation coefficients rho (P < 0.05). ResultsPatients had larger mGPS (+1.9°) and EMG-Profile Scores (+50%) and walked on average slower (−0.26 m/s) than controls. EMG patterns revealed higher activation of multifidus, erector spinae and gluteus medius during midstance in patients compared to controls. Clinical scores (pain, ODI) did not correlate with mGPS or EMG-Profile Scores within patients. SignificanceObserved differences in gait and muscle activation patterns and in the summary scores of gait and EMG deviations between patients with sLSS and healthy controls may represent additional functional outcomes reflecting the functional status of patients that can be measured using wearable sensors and hence is suitable for application in clinical practice.

The Foot and Ankle Kinematics of a Simulated Progressive Collapsing Foot Deformity During Stance Phase: A Cadaveric Study.

Progressive collapsing foot deformity (PCFD) is a complex pathology associated with tendon insufficiency, ligamentous failure, joint malalignment, and aberrant plantar force distribution. Existing knowledge of PCFD consists of static measurements, which provide information about structure but little about foot and ankle kinematics during gait. A model of PCFD was simulated in cadavers (sPCFD) to quantify the difference in joint kinematics and plantar pressure between the intact and sPCFD conditions during simulated stance phase of gait. In 12 cadaveric foot and ankle specimens, the sPCFD condition was created via sectioning of the spring ligament and the medial talonavicular joint capsule followed by cyclic axial compression. Specimens were then analyzed in intact and sPCFD conditions via a robotic gait simulator, using actuators to control the extrinsic tendons and a rotating force plate underneath the specimen to mimic the stance phase of walking. Force plate position and muscle forces were optimized using a fuzzy logic iterative process to converge and simulate in vivo ground reaction forces. An 8-camera motion capture system recorded the positions of markers fixed to bones, which were then used to calculate joint kinematics, and a plantar pressure mat collected pressure distribution data. Joint kinematics and plantar pressures were compared between intact and sPCFD conditions. The sPCFD condition increased subtalar eversion in early, mid-, and late stance (P < .05), increased talonavicular abduction in mid- and late stance (P < .05), and increased ankle plantarflexion (P < .05), adduction (P < .05), and inversion (P < .05). The center of plantar pressure was significantly (P < .01) medialized in this model of sPCFD and simulated stance phase of gait. Subtalar and talonavicular joint kinematics and plantar pressure distribution significantly changed with the sPCFD and in the directions expected from a PCFD foot. We also found that ankle joint kinematics changed with medial and plantar drift of the talar head, indicating abnormal talar rotation. Although comparison to an in vivo PCFD foot was not performed, this sPCFD model produced changes in foot kinematics and indicates that concomitant abnormal changes may occur at the ankle joint with PCFD. This study describes the dynamic kinematic and plantar pressure changes in a cadaveric model of simulated progressive collapsing foot deformity during simulated stance phase.

Long-term functional recovery in patients with custom-made 3D-printed anatomical pelvic prostheses following bone tumor excision

BackgroundAnatomical custom-made prostheses make it possible to reconstruct complicated bone defects following excision of bone tumors, thanks to 3D-printed technology. To date, clinical measures have been used to report clinical-functional outcome and provide evidence for the effectiveness of this new surgical approach. However, there are no studies that quantified the achievable recovery during common activities by using instrumental clinical-functional evaluation in these patients. Research questionWhat is the motor performance, functional outcome and quality of life in patients with custom-made 3D-printed pelvic prostheses following bone tumor? MethodsTo analyze motor performance, six patients performed motion analysis during five motor activities at follow-up of 32 ± 18 months. Joint angles, ground reaction forces and joint moments of the operated and contralateral limbs were compared. On-off activity of lower-limb muscles were calculated from electromyography and compared to a healthy matched population. To analyze functional outcome and quality of life, differences in measured hip abductor strength between limbs were evaluated, as well as clinical-functional scores (Harris Hip Score, Barthel Index, Musculoskeletal Tumor Society score), and quality of life (SF-36 health survey). ResultsWe found only slight differences in joint kinematics when comparing operated and contralateral limb. The activity of gluteal muscles was normal, while hamstrings showed out-of-phase activities. Ground reaction forces and hip moments showed asymmetries between limbs, particularly in more demanding motor activities. We found a mean difference in hip abductor strength of 48 ± 82 N between limbs, good clinical-functional scores, and quality of life scores within normative. SignificanceOur study showed optimal long-term results in functional recovery, mainly achieved through recovery of the gluteal function, although minor impairments were found, which may be considered for future improvement of this innovative surgery. The effect of a more loaded contralateral limb on internal loads and long-term performance of the implant remains unknown and deserves further investigation.

Inter-limb differences in in-vivo tendon behavior, kinematics, kinetics and muscle activation during running

Overloading of tendon tissue may result in overuse tendon injuries in runners. One possible cause of overloading could be the occurrence of biomechanical inter-limb differences during running. However, scarce information exists concerning the simultaneous analysis of inter-limb differences in external and internal loading-related variables in habitual runners. In this study ground reaction force, joint kinematics, triceps surae and tibialis anterior activations, and medial gastrocnemius muscle-tendon junction displacement were assessed bilaterally during treadmill running at 2.7 m.s−1 and 4.2 m.s−1. Statistical parametric t-tests and effect sizes were calculated to identify eventual inter-limb differences across the stance phase and stride cycle. Hip flexion angle was 9° greater (p = 0.03, ES = 0.30) in the non-preferred limb during the flight phase at 4.2 m.s−1. Hip extension velocity was 45 deg.s−1 greater (p = 0.04, ES = 0.41) during ground contact and 25 deg.s−1 greater (p = 0.02, ES = 0.41) immediately after toe-off in the non-preferred limb at 4.2 m.s−1. Hip extension velocity was also 40 deg.s−1 greater (p = 0.01, ES = 0.46) in the non-preferred limb prior to touch-down at 4.2 m.s−1. Brief inter-limb differences in joint kinematics were not accompanied by inter-limb differences in variables associated to internal loading, suggesting they are unlikely to be underlying factors leading to tendon overloading in healthy non-injured runners.

Patient and Implant Performance of Satisfied and Dissatisfied Total Knee Arthroplasty Patients.

Implant migration and altered kinematics have been thought to impact patient-reported outcome measures (PROMs) and postoperative patient satisfaction. In this study comparing satisfied and dissatisfied total knee arthroplasty (TKA) patients, we hypothesized that dissatisfied patients will have greater continuous implant migration and that there will be differences in joint kinematics, objective functional measurements, and PROMs between satisfied and dissatisfied patients. The Knee Society Score Satisfaction Subsection questions regarding satisfaction with function were used at least 6 months postoperation to split 50 patients into satisfied and dissatisfied groups. Patients underwent radiostereometric analysis to evaluate migration and kinematics. A wearable sensor system obtained objective measurements of patient function during timed up and go tests. PROMs were recorded preoperation and postoperation. No statisticallysignificant differences were found in migration between satisfied and dissatisfied groups. Statistical kinematic differences existed in lateral anteroposterior contact location at 20° and 40° of flexion at 1 year, where the dissatisfied group had more anteriorly located lateral contact. No statisticallysignificant differences were present in objective functional measurements. Satisfied and dissatisfied groups had differing PROMs at 4 timepoints or greater for each questionnaire. No differences were found in tibial component migration or objectively measured function between satisfied and dissatisfied patients. Functionally dissatisfied patients had more anteriorly positioned contact on the lateral condyle in early flexion and reported more pain and unmet expectations. These findings suggest that improving the functional satisfaction of TKA requires restoration of kinematics in early flexion and management of patient's pain and expectations.

Variable Stiffness Shoes for Knee Osteoarthritis: An Evaluation of 3-Dimensional Gait Mechanics and Medial Joint Contact Forces.

The study aim was to quantify the impact of a commercially available variable stiffness shoe (VSS) on 3-dimensional ankle, knee, and hip mechanics and estimated knee contact forces compared with a control shoe. Fourteen participants (10females) with knee osteoarthritis completed gait analysis after providing informed consent. Shoe conditions tested were control shoe (New Balance MW411v2) and VSS (Abeo SMART3400). An OpenSim musculoskeletal model with static optimization was used to estimate knee contact forces. There were no differences in joint kinematics or in the knee adduction or flexion moments (P = .06; P = .2). There were increases in the knee internal and external rotation (P = .02; P = .03) and hip adduction and internal rotation moments for VSS versus control (P = .03; P = .02). The estimated contact forces were not different between shoes (total P = .3, medial P = .1, and lateral P = .8), but contact force changes were correlated with changes in the knee adduction moment (medial r2 = .61; P < .007). High variability in knee flexion moment changes and increases in the internal rotation moment combined with small decreases in the knee adduction moment did not lead to decreases in estimated contact forces. These results suggest that evaluation of VSS using only the knee adduction moment may not adequately capture its impact on osteoarthritis.

Influence of hamstring flexibility on running kinematics in adolescent long-distance runners

BackgroundStudies have found no or minimal differences in running kinematics between flexible and inflexible adult runners. The interaction between hamstring flexibility and running kinematics has not been reported in adolescent long-distance runners. Research questionDoes hamstring flexibility influence running kinematics in adolescent long-distance runners? MethodsAdolescent long-distance runners (n = 140, ages 9–19) were enrolled in our cross-sectional study. Hamstring flexibility was assessed with the forward bending Beighton task. Runners were categorized if they tested positive or negative on the forward bending task. Participants ran at a comfortable self-selected speed on a treadmill. Runners who tested positive on the forward bending task (n = 17) were matched with runners who tested negative on the task (n = 17) according to sex, physical maturation, and running speed. Statistical parametric mapping compared trunk, pelvis, hip, and knee kinematic waveforms throughout the gait cycle and independent sample t tests compared temporal-spatial parameters between the groups. ResultsRunners who tested positive on the forward bending task demonstrated significantly greater anterior pelvic tilt during stance (average difference = 4.8° ± 0.4°, p < .001) and swing (average difference = 4.3° ± 0.2°, p < .01) compared to runners who tested negative on the forward bending task. No significant differences were found between groups for the remaining kinematic waveforms or for any temporal-spatial parameters (p > .05). SignificanceThis is the first study to report the interaction between hamstring flexibility and running kinematics in adolescent long-distance runners. The greater anterior pelvic tilt demonstrated by runners with greater hamstring flexibility may place more eccentric demands on the hamstring musculature. However, as there were no other differences in joint kinematics or temporal-spatial parameters between groups, greater hamstring flexibility does not appear to have a significant interaction with running kinematics when running at sub-maximal speeds. Our results suggest hamstring flexibility does not predispose adolescent long-distance runners to sub-optimal segment positions associated with running-related injuries.

Effects of body mass and sex on kinematics and kinetics of the lower extremity during stair ascent and descent in older adults

The effects of body mass and sex on lower limb biomechanics during ascent and descent were examined in participants aged 50 to 75 with normal weight (n ​= ​19), overweight (n ​= ​18), and obese (n ​= ​8). Peak joint angles and joint moment of the lower limb were analyzed with the VICON motion analysis system. Results from multivariate analysis of variance showed that during descent, the overweight participants had significantly higher knee extensor moment (0.98 ​± ​0.30 ​N∙m/kg-1) than the normal-weight participants (0.70 ​± ​0.29 ​N∙m/kg-1). The obese group had significantly higher ankle abductor moment (0.21 ​± ​0.11 ​N∙m/kg-1) than the normal weight (0.12 ​± ​0.08 ​N∙m/kg-1) and overweight groups (0.09 ​± ​0.06 ​N∙m/kg-1). During ascent, the obese participants had significant higher hip flexor moment (0.42 ​± ​0.20 ​N∙m/kg-1) than overweight participants (0.22 ​± ​0.17 ​N∙m/kg-1). Significant sex differences were found in knee extension angles (4.2 ​± ​3.4° vs 7.0 ​± ​3.3°) during descent, plantar flexion angles during ascent (23.7 ​± ​5.3° vs 15.6 ​± ​3.7°) and descent (29.9 ​± ​5.0° vs 22.1 ​± ​7.9°), and ankle adduction angles (6.8 ​± ​4.8° vs 2.5 ​± ​2.5°) during ascent. It is concluded that body mass has significant impact on joint loading of lower limbs during stair walking. Being overweight and obese increased hip joint loading during ascent, and knee and ankle joint loading during descent in older adults. Sex difference in joint kinematics was presented during stair walking regardless of the body mass.

Age and sex differences in normative gait patterns.

A comprehensive understanding of healthy gait patterns is a critical first step towards understanding age-related pathologies and disorders that are commonly associated with mobility limitations throughout aging. Further, consideration of sex-specific gait patterns throughout the lifespan is important, considering biological differences between males and females that can manifest biomechanically, and epidemiological evidence of female sex being a risk factor for some age-related pathologies such as osteoarthritis. The aim of this study was to characterize the differences in lower extremity joint kinematics and kinetics during gait between asymptomatic adult women and men in different age groups (20-40 years, 41-50 years, 51-59 years, 60+ years). This was a secondary analysis conducted on instrumented gait data from 154 asymptomatic adult participants (94 females, 60 males). Three-dimensional hip, knee and ankle joint angles and net external moments were calculated and waveform principal component analysis (PCA) was applied to extract major patterns of variability from each. PC scores were examined for significant sex, age and interaction effects using a two-factor ANOVA analysis (p = 0.001). 13 PC features differed between asymptomatic male and female gait patterns, and were independent of age category. No PC features significantly differed between the age groups, and there were no significant sex by age interactions. There are significant magnitude and pattern differences in hip, knee and ankle kinematics and kinetics between asymptomatic women and men. As study participants were asymptomatic, these differences do not necessarily correlate with any injury or disease mechanisms. However, these results do suggest the importance of considering sex-specific analyses in gait study design, and the use of sex-specific normative data in clinical gait studies. These results further suggest that consideration of strict age-matching for gait analysis studies using adult controls is not as critical as sex considerations.

A Comparative Biomechanical Analysis during Planned and Unplanned Gait Termination in Individuals with Different Arch Stiffnesses

Although values of arch stiffness index (ASI) have been used to evaluate arch structure and injury susceptibility, investigations are limited regarding the influence of ASI on biomechanical characteristics during gait termination, which involves a challenging balance transition from walking to standing. This study aimed to explore plantar pressure distribution and lower extremity joint kinematic differences between individuals with both a stiff and flexible arch (SA and FA, respectively) during planned and unplanned gait termination (PGT and UGT, respectively). Following the calculation of ASI, sixty-five asymptomatic male subjects were classified and participated in two types of gait termination tests to acquire kinematic and plantar pressure data. Parameters were compared between SA and FA using a two-way ANOVA during PGT and UGT, respectively. UGT was found to have a larger range of motion on the hip joint in the sagittal plane and the knee joint in the transverse plane when compared with PGT. The differences in the kinematic characteristics of the lower limb joints caused by the difference in arch stiffness are mainly concentrated in the ankle and metatarsophalangeal joints. Plantar pressure data, represented by the maximum pressure, showed significant differences in the forefoot and rearfoot areas. These results suggest that ASI could change freedom of motion of the lower limb joints, and UGT tends to conduct a compensatory adjustment for the lower extremity kinetic chain. An understanding of the biomechanical characteristics of arch structures may provide additional insights into foot function and injury prediction during gait termination.