Sagittal Plane Joint Research Articles

Gait deficiencies associated with peripheral artery disease are different than chronic obstructive pulmonary disease

ObjectivePrevious studies have indicated that patients with peripheral artery disease (PAD), display significant differences in their kinetic and kinematic gait characteristics when compared to healthy, aged-matched controls. The ability of patients with chronic obstructive pulmonary disease (COPD) to ambulate is also limited. These limitations are likely due to pathology-driven muscle morphology and physiology alterations establish in PAD and COP, respectively. Gait changes in PAD were compared to gait changes due to COPD to further understand how altered limb muscle due to disease can alter walking patterns. Both groups were independently compared to healthy controls. It was hypothesized that both patients with PAD and COPD would demonstrate similar differences in gait when compared to healthy controls. MethodsPatients with PAD (n=25), patients with COPD (n=16), and healthy older control subjects (n=25) performed five walking trials at self-selected speeds. Sagittal plane joint kinematic and kinetic group means were compared. ResultsPeak values for hip flexion angle, braking impulse, and propulsive impulse were significantly reduced in patients with symptomatic PAD compared to patients with COPD. After adjusting for walking velocity, significant reductions (p<0.05) in the peak values for hip flexion angle, dorsiflexor moment, ankle power generation, propulsion force, braking impulse, and propulsive impulse were found in patients with PAD compared to healthy controls. No significant differences were observed between patients with COPD and controls. ConclusionsThe results of this study demonstrate that while gait patterns are impaired for patients with PAD, this is not apparent for patients with COPD (without PAD). PAD (without COPD) causes changes to the muscle function of the lower limbs that affects gait even when subjects walk from a fully rested state. Altered muscle function in patients with COPD does not have a similar effect.

Effect of valgus knee alignment on gait biomechanics in healthy women

The purpose of this study was to compare lower extremity kinematics and kinetics between women with greater or lesser degrees of valgus knee alignment during gait. Nine women with greater valgus knee alignment (11.9±1.6°) were compared to nine women with lesser valgus knee alignment (6.6±2.4°). Participants completed a biomechanical assessment of overground walking for the right limb. Dependent variables included sagittal and frontal plane joint angles and moments for the hip, knee, and ankle at peak vertical ground reaction force, along with knee abduction angular impulse. Sagittal and frontal plane excursions for the hip, knee, and ankle were calculated from heel strike to the peak angle for each variable. The greater valgus alignment group demonstrated lower knee abduction moment (p=0.007), lower knee adduction angle (p<0.001), and greater ankle inversion moment (p=0.034) at peak vertical ground reaction force, as well as lower knee abduction angular impulse (p=0.007), and knee adduction ROM (p=0.026). No other group differences were identified for any kinematic or kinetic variables (p>0.05). Less knee adduction angle and excursion coupled with lower knee abduction moment and angular impulse in women with greater knee valgus indicates these individuals may be experiencing biomechanics which promote lateral tibiofemoral joint loading.

Association Between Rate of Torque Development, Strength, Landing Biomechanics, And Dynamic Postural Stability In Physically Active Males

During exercise and sport, physically active individuals often perform movements that require dynamic postural stabilization. Postural stability has been linked to ankle and knee injuries and examining factors associated with stabilization may provide insight as to how poor stability influences joint loading. PURPOSE: To examine mechanisms associated with postural stability during a Forward Jump Single-Leg Landing task (FJSL). METHODS: Dynamic postural stability index (DPSI), a composite of the anterior-posterior, medial-lateral, and vertical ground reaction forces, kinematics, knee extension strength (KES), and knee extension rate of torque development (RTD) were collected on 23 males (Age: 23.9 ± 1.3 years, Height: 178.4 ± 7.1 cm, Mass: 84.4 ± 8.6 kg). KES and RTD were collected using an isokinetic dynamometer. DPSI, sagittal plane joint angles at initial contact ([email protected], [email protected], [email protected]) and peak flexion angles (KneePkFlex, ANKPkFlex) were collected during a FJSL for the dominant (DOM) and non-dominant (NON) limb using a 3D motion capture system. Paired samples t-tests examined lower extremity asymmetries in DPSI, kinematics, KES, and RTD. Pearson correlation coefficients examined the relationships between KES, RTD, DPSI, and landing kinematics. Significance was set at p≤0.05. RESULTS: Subjects demonstrated asymmetrical DPSI (p=0.003) and asymmetrical ANKPkFlex (p=0.033) but not asymmetrical KES or RTD (p>0.05). Increased KneePkFlex and ANKPkFlex correlated with an improved DPSI (r=-0.519, p=0.016 and r=-0.466, p=0.033) on the DOM limb while KneePkFlex and [email protected] correlated with an improved DPSI on the NON limb (r=-0.472, p=0.031 and r=-0.520, p=0.016). Neither KES nor RTD correlated with DSPI or any of the kinematic measures for their respective sides. (p>0.05). CONCLUSIONS: Biomechanical stabilization strategies utilized the knee but the DOM, which had better stabilization, incorporated more ANKPkFlex, likely distributing weight over the forefoot. Neither strategy related to KES or RTD. Incorporating movement and balance components focused on symmetrical coordination of corrective movement strategies, including ankle stability, into current training programs may be necessary for improved dynamic postural stabilization.

Age Effects on Sagittal Plane Joint Powers during Submaximal Cycling

Age Effects on Sagittal Plane Joint Powers during Submaximal Cycling

Dual-belt treadmill familiarization: Implications for knee function in moderate knee osteoarthritis compared to asymptomatic controls

BackgroundEffect of treadmill familiarization on knee function in osteoarthritis is not clear. Purpose was to determine whether spatiotemporal characteristics, knee joint biomechanics and muscle activation patterns change as individuals with and without medial compartment knee osteoarthritis familiarize to dual-belt treadmill walking over 6min. Methods20 individuals with knee osteoarthritis and 20 asymptomatic controls walked at a self-selected speed. Spatiotemporal characteristics, sagittal plane joint motions, sagittal and frontal plane moments and knee joint muscle activation patterns, amplitude normalized to maximum isometric contractions were analyzed. Discrete measures were extracted from each biomechanical waveform and principal component analysis was used to determine knee joint muscle activation patterns. Statistical significance was determined using Analysis of Variance models (alpha=0.05). FindingsSpatiotemporal gait characteristics, knee motion and moment differences were found between groups however no group by time interactions existed and no changes in these variables were found over 6min of walking. Group differences in muscle activation patterns were found in all muscle activations. Muscle activation amplitude and patterns at minute 5 and 6 were generally lower, less prolonged and more dynamic when compared to minute 1 and 3. InterpretationIndividuals with and without medial compartment knee osteoarthritis familiarized to treadmill walking in a similar manner. Minimal changes to knee biomechanics were found during treadmill familiarization. Five to six minutes of familiarization should be considered for surface electromyography in these populations.

Sagittal plane joint kinetics during stair ascent in patients with peripheral arterial disease and intermittent claudication

Stair negotiation poses a substantial physical demand on the musculoskeletal system and this challenging task can place individuals at risk of falls. Peripheral arterial disease (PAD) can cause intermittent claudication (IC) pain in the calf and results in altered gait mechanics during level walking. However, whether those with PAD-IC adopt alternate strategies to climb stairs is unknown. Twelve participants with PAD-IC (six bilateral and six unilateral) and 10 healthy controls were recruited and instructed to ascend a five-step staircase whilst 3D kinematic data of the lower-limbs were recorded synchronously with kinetic data from force plates embedded into the staircase on steps two and three. Limbs from the unilateral group and both limbs from the bilateral claudicants were categorised as claudicating (N=18), asymptomatic (N=6) and control (N=10). Claudicants walked more slowly than healthy controls (trend; P=<0.066). Both claudicating- and asymptomatic-limb groups had reduced propulsive GRF (P=0.025 and P=0.002, respectively) and vertical GRF (P=0.005 and P=0.001, respectively) compared to controls. The claudicating-limb group had a reduced knee extensor moment during forward continuance (P=0.060), ankle angular velocity at peak moment (P=0.039) and ankle power generation (P=0.055) compared to the controls. The slower gait speed, irrespective of laterality of symptoms, indicates functional capacity was determined by the limitations of the claudicating limb. Reduced ankle power generation and angular velocity (despite adequate plantarflexor moment) implies velocity-dependent limitations existed in the calf. The lack of notable compensatory strategies indicates reliance on an impaired muscle group to accomplish this potentially hazardous task, highlighting the importance of maintaining plantarflexor strength and power in those with PAD-IC.

Measuring joint kinematics of treadmill walking and running: Comparison between an inertial sensor based system and a camera-based system

Inertial sensor systems are becoming increasingly popular for gait analysis because their use is simple and time efficient. This study aimed to compare joint kinematics measured by the inertial sensor system RehaGait® with those of an optoelectronic system (Vicon®) for treadmill walking and running. Additionally, the test re-test repeatability of kinematic waveforms and discrete parameters for the RehaGait® was investigated. Twenty healthy runners participated in this study. Inertial sensors and reflective markers (PlugIn Gait) were attached according to respective guidelines. The two systems were started manually at the same time. Twenty consecutive strides for walking and running were recorded and each software calculated sagittal plane ankle, knee and hip kinematics. Measurements were repeated after 20min. Ensemble means were analyzed calculating coefficients of multiple correlation for waveforms and root mean square errors (RMSE) for waveforms and discrete parameters. After correcting the offset between waveforms, the two systems/models showed good agreement with coefficients of multiple correlation above 0.950 for walking and running. RMSE of the waveforms were below 5° for walking and below 8° for running. RMSE for ranges of motion were between 4° and 9° for walking and running. Repeatability analysis of waveforms showed very good to excellent coefficients of multiple correlation (>0.937) and RMSE of 3° for walking and 3–7° for running. These results indicate that in healthy subjects sagittal plane joint kinematics measured with the RehaGait® are comparable to those using a Vicon® system/model and that the measured kinematics have a good repeatability, especially for walking.

Enhanced arm swing alters interlimb coordination during overground walking in individuals with traumatic brain injury

The current study investigated interlimb coordination in individuals with traumatic brain injury (TBI) during overground walking. The study involved 10 participants with coordination, balance, and gait abnormalities post-TBI, as well as 10 sex- and age-matched healthy control individuals. Participants walked 12m under two experimental conditions: 1) at self-selected comfortable walking speeds; and 2) with instructions to increase the amplitude and out-of-phase coordination of arm swinging. The gait was assessed with a set of spatiotemporal and kinematic parameters including the gait velocity, step length and width, double support time, lateral displacement of the center of mass, the amplitude of horizontal trunk rotation, and angular motions at shoulder and hip joints in sagittal plane. Interlimb coordination (coupling) was analyzed as the relative phase angles between the left and right shoulders, hips, and contralateral shoulders and hips, with an ideal out-of-phase coupling of 180° and ideal in-phase coupling of 0°. The TBI group showed much less interlimb coupling of the above pairs of joint motions than the control group. When participants were required to increase and synchronize arm swinging, coupling between shoulder and hip motions was significantly improved in both groups. Enhanced arm swinging was associated with greater hip and shoulder motion amplitudes, and greater step length. No other significant changes in spatiotemporal or kinematic gait characteristics were found in either group. The results suggest that arm swinging may be a gait parameter that, if controlled properly, can improve interlimb coordination during overground walking in patients with TBI.

Which Prosthetic Foot to Prescribe?: Biomechanical Differences Found during a Single-Session Comparison of Different Foot Types Hold True 1 Year Later

ABSTRACT Introduction Clinicians typically use findings from cohort studies to objectively inform judgments regarding the potential (dis)advantages of prescribing a new prosthetic device. However, before finalizing prescription, a clinician will typically ask a patient to “try out” a change of prosthetic device while the patient is at the clinic. Observed differences in gait when using the new device should be the result of the device's mechanical function but could also conceivably be a result of patient-related factors, which can change from day to day and can thus make device comparisons unreliable. To determine whether a device's mechanical function consistently has a more meaningful impact on gait than patient-related factors, the present study undertook quantitative gait analyses of an individual with a transtibial amputation walking using two different foot-ankle devices on two occasions over a year apart. If the observed differences present between devices, established using quantitative gait analysis, were in the same direction and of similar magnitude on each of the two occasions, this would indicate that device-related factors were more important than patient-related factors. Materials and Methods One adult man with a unilateral transtibial amputation completed repeated walking trials using two different prosthetic foot devices on two separate occasions, 14 months apart. Walking speed and sagittal plane joint kinematics and kinetics for both limbs were assessed on each occasion. Clinically meaningful differences in these biomechanical outcome variables were defined as those with an effect size difference (d) between prosthetic conditions of at least 0.4 (i.e., medium effect size). Results Eight variables, namely, walking speed, prosthetic ankle peak plantarflexion and dorsiflexion, and peak positive power and residual knee loading response flexion, peak stance-phase extension and flexion moments, and peak negative power, displayed clinically meaningful differences (d &gt; 0.4) between foot devices during the first session. All eight of these showed similar effect size differences during the second session despite the participant being heavier and older. Conclusions Findings suggest that a prosthetic device's mechanical function consistently has a more meaningful impact on gait than patient-related factors do. These findings support the current clinical practice of making decisions regarding prosthetic prescription for an individual based on a single-session evaluation of his/her gait using two different devices. However, to confirm this conclusion, a case series using the same approach as the present study could be undertaken.

Adaptive changes in running kinematics as a function of head stability demands and their effect on shock transmission

This study aimed to identify adaptive changes in running kinematics and impact shock transmission as a function of head stability requirements. Fifteen strides from twelve recreational runners were collected during preferred speed treadmill running. Head stability demands were manipulated through real-time visual feedback that required head-gaze orientation to maintain within boxes of different sizes, ranging from 21° to 3° of visual angle with 3° decrements. The main outcome measures were tibial and head peak accelerations in the time and frequency domains (impact and active phases), shock transmission from tibia to head, stride parameters, and sagittal plane joint kinematics. Increasing head stability requirements resulted in decreases in the amplitude and integrated power of head acceleration during the active phase of stance. During the impact portion of stance tibial and head acceleration and shock transmission remained similar across visual conditions. In response to increased head stability requirements, participants increased stride frequency approximately 8% above preferred, as well as hip flexion angle at impact; stance time and knee and ankle joint angles at impact did not change. Changes in lower limb joint configurations (smaller hip extension and ankle plantar-flexion and greater knee flexion) occurred at toe-off and likely contributed to reducing the vertical displacement of the center of mass with increased head stability demands. These adaptive changes in the lower limb enabled runners to increase the time that voluntary control is allowed without embedding additional impact loadings, and therefore active control of the head orientation was facilitated in response to different visual task constraints.

Altered Sagittal- and Frontal-Plane Kinematics Following High-Intensity Stepping Training Versus Conventional Interventions in Subacute Stroke.

Common locomotor deficits observed in people poststroke include decreased speeds and abnormal kinematics, characterized by altered symmetry, reduced sagittal-plane joint excursions, and use of compensatory frontal-plane behaviors during the swing phase of gait. Conventional interventions utilized to mitigate these deficits often incorporate low-intensity, impairment-based or functional exercises focused on normalizing kinematics, although the efficacy of these strategies is unclear. Conversely, higher-intensity training protocols that provide only stepping practice and do not focus on kinematics have demonstrated gains in walking function, although minimal attention toward gait quality may be concerning and has not been assessed. The present study evaluated changes in spatiotemporal and joint kinematics following experimental, high-intensity stepping training compared with conventional interventions. Kinematic data were combined from a randomized controlled trial comparing experimental and conventional training and from a pilot experimental training study. Individuals with gait deficits 1 to 6 months poststroke received up to 40 sessions of either high-intensity stepping training in variable contexts or conventional lower-intensity interventions. Analyses focused on kinematic changes during graded treadmill testing before and following training. Significant improvements in speed, symmetry, and selected sagittal-plane kinematics favored experimental training over conventional training, although increases in compensatory strategies also were observed. Changes in many kinematic patterns were correlated with speed changes, and increased compensatory behaviors were associated with both stride length gains and baseline impairments. Limitations include a small sample size and use of multiple statistical comparisons. Improved speeds and selected kinematics were observed following high-intensity training, although such training also resulted in increased use of compensatory strategies. Future studies should explore the consequences of utilizing these compensatory strategies despite the observed functional gains.

Predicting Jump Performance Using Biomechanics Of Various Versions Of The Kettlebell Swings

Research on kettlebell (KB) and indian club (IC) training is limited, particularly related to its transferability to power development. Initial research suggests KB training may be as effective for the development of vertical jump performance as more traditional strength training. However, to date there are no studies examining the relationship between KB or IC swing performance and vertical jump performance. PURPOSE: To determine how different styles of KB and IC swings predict vertical and broad jump flight time. METHODS: Fifteen active and healthy adults with KB swing experience participated in a 3D biomechanical evaluation of their overhead KB swing (OKS), shoulder height KB swing (SKS), indian club swings (IC), vertical jumps (VJ) and broad jumps (BJ). Kinematic and kinetic data were collected during three consecutive 10 repetition trials of each of the swing movements. Peak sagittal plane joint angles and joint moments as well as vertical and anterior-posterior ground reaction forces were extracted for the down and up portions of the swing movement. Extracted variables for the right side were entered into a stepwise regression to identify which variables predicted vertical jump flight time and broad jump flight time. Variables were retained if the model was statistically significant at p< .05, and each variable was extracted if the variable caused the model to exceed p=.10. RESULTS: Biomechanical variables extracted from the OKS significantly explained VJ flight time (r-squared = .56+/- .06) and BJ flight time (r-squared = .30+/- .05). Similarly, kinematic and kinetic variables during the SKS significantly explained the VJ flight time (r-squared = .93+/- .02) and BJ flight time (r-squared = .57+/- .04). Finally, biomechanical variables during the IC performance significantly explained the VJ flight time (r-squared = .72+/- .04) and the BJ flight time (r-squared = .34+/- .05). CONCLUSIONS: The results of this study demonstrate that biomechanics during kettlebell and indian club swings explain a large percentage of vertical and broad jump performance. Surprisingly, the greatest amount of variability in jumping performance was explained by variables present in the IC pattern. Therefore, power development from the indian club swing pattern may have the greatest potential to transfer into jumping performance.

The Biomechanical Research Of Lower Extremity During Stance Phase Of Walking In Knee Osteoarthritis Patients

PURPOSE: The purpose of the current study was to find biomechanics sensitive index of evaluating knee osteoarthritis gait and supply biomechanics theoretical basis for the prevention and rehabilitation of knee osteoarthritis. METHODS: In a gait laboratory, Each subject walked at a self-selected, comfortable pace on a 10-m walkway.A 16-camera motion analysis system and two Kistler force platforms were used to measure kinematic and kinetic data of 13 OA patients(65.9±4.1years,58.1±8.6kg) and 13 controls(63.4±2.3years,55.4±5.8kg) during walking. Intersegmental model of lower extremity joints was built on the basis of conventional kinematic and kinetic analysis.The relationship between active muscle torque and passive torques of hip, knee and ankle joints in two different groups were explored thoroughly. All variables characterizing sagittal-plane joint function were compared between the two groups using Independent-Samples T test. The level of significance for the T test was set at α=0.05. RESULTS: 1. Significant reductions were observed for the OA group compared to the control group in terms of the stride length(1.23±0.09m vs. 1.39±0.09m; P=0.0001) and gait speed(1.28±0.12m/s vs. 1.39±0.13m/s; P=0.03). 2. During the heel-strike portion(hs),midstance portion(ms) and terminal portion(ts) of the stance phase, Significant differences were obtained in the peak angle of left knee between OA and control groups(-6.9°±1.9° vs. -2.2°±1.6°; Phs=0.001;-16.6°±2.5° vs. -18.0°±2.6°; Pms=0.03;-9.2°±2.3° vs. -5.5°±1.9°; Pts=0.001). Besides, knee extensor muscle torque of heel-strike(KFMhs)in OA group are less than that in control group (-16.38±5.55Nm/kg vs. -23.88±9.27Nm/kg; P=0.019). 3. Interactive torque(INT)of ankle in OA group was lower than that in control group during the whole stance phase (INTOA=0.0055±0.0061, INTc=0.0134±0.0078; P<0.01). CONCLUSION: The change of extensor and flexor muscles’ activity in lower extremity induced by knee osteoarthritis will alter the peak angle and muscle torque of knee in different portions of stance phase. So these variables could be considered to be non-invasive diagnostic index in biomechanics of knee osteoarthritis.

Recovery From a First-Time Lateral Ankle Sprain and the Predictors of Chronic Ankle Instability

Background: Impairments in motor control may predicate the paradigm of chronic ankle instability (CAI) that can develop in the year after an acute lateral ankle sprain (LAS) injury. No prospective analysis is currently available identifying the mechanisms by which these impairments develop and contribute to long-term outcome after LAS. Purpose: To identify the motor control deficits predicating CAI outcome after a first-time LAS injury. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Eighty-two individuals were recruited after sustaining a first-time LAS injury. Several biomechanical analyses were performed for these individuals, who completed 5 movement tasks at 3 time points: (1) 2 weeks, (2) 6 months, and (3) 12 months after LAS occurrence. A logistic regression analysis of several “salient” biomechanical parameters identified from the movement tasks, in addition to scores from the Cumberland Ankle Instability Tool and the Foot and Ankle Ability Measure (FAAM) recorded at the 2-week and 6-month time points, were used as predictors of 12-month outcome. Results: At the 2-week time point, an inability to complete 2 of the movement tasks (a single-leg drop landing and a drop vertical jump) was predictive of CAI outcome and correctly classified 67.6% of cases (sensitivity, 83%; specificity, 55%; P = .004). At the 6-month time point, several deficits exhibited by the CAI group during 1 of the movement tasks (reach distances and sagittal plane joint positions at the hip, knee and ankle during the posterior reach directions of the Star Excursion Balance Test) and their scores on the activities of daily living subscale of the FAAM were predictive of outcome and correctly classified 84.8% of cases (sensitivity, 75%; specificity, 91%; P < .001). Conclusion: An inability to complete jumping and landing tasks within 2 weeks of a first-time LAS and poorer dynamic postural control and lower self-reported function 6 months after a first-time LAS were predictive of eventual CAI outcome.

Immediate Effects of a Brace on Gait Biomechanics for Predominant Lateral Knee Osteoarthritis and Valgus Malalignment After Anterior Cruciate Ligament Reconstruction

Background: Lateral knee osteoarthritis is notably common after anterior cruciate ligament reconstruction (ACLR). While valgus bracing has been investigated as an intervention for medial knee osteoarthritis (OA), little is known about the effectiveness of varus bracing for lateral knee OA after ACLR. Purpose: To determine the immediate effects of a varus unloader knee brace on gait biomechanics in people with lateral knee OA and valgus malalignment after ACLR. Study Design: Controlled laboratory study. Methods: Nineteen participants who had undergone primary ACLR 5 to 20 years previously and had symptomatic and radiographic lateral knee OA as well as valgus malalignment were included. Three-dimensional gait analyses were conducted during walking under 3 test conditions: (1) no brace, (2) unadjusted brace (sagittal plane support with neutral frontal plane adjustment), and (3) adjusted brace (sagittal plane support with varus adjustment). Knee, pelvis, hip, and ankle kinematics and moments data were statistically analyzed using repeated-measures analysis of variance (α = 0.05). Results: Compared with walking with no brace, the adjusted brace significantly increased peak knee flexion angle (mean difference [95% CI]: 3.2° [1.3° to 5.0°]) and adduction angle (1.7° [0.8° to 2.6°]) and reduced peak internal rotation angle (−3.0° [−4.0° to −2.0°]). Significant increases in peak knee flexion moment (0.14 N·m/kg [0.06 to 0.20 N·m/kg]), adduction moment (0.10 N·m/kg [0.07 to 0.14 N·m/kg]), and external rotation moment (0.01 N·m/kg [0.00 to 0.02 N·m/kg]) were observed with the adjusted brace. The adjusted brace also reduced peak hip adduction angle (−1.29° [−2.12 to −0.47]) and increased peak hip adduction (0.17 N·m/kg [0.04 to 0.31 N·m/kg]) and external rotation moments (0.09 N·m/kg [0.03 to 0.14 N·m/kg]). There were no significant differences between the adjusted and unadjusted brace conditions, except for knee internal rotation angle, where the adjusted brace produced significantly greater reductions relative to the unadjusted brace (−1.46° [−1.98 to −0.95]). Conclusion: Irrespective of frontal plane adjustment, the varus unloader brace produced immediate modulations in sagittal, frontal, and transverse plane joint angles and moments in younger individuals with lateral knee OA and valgus malalignment after ACLR. Clinical Relevance: The varus unloader brace may have the potential to mitigate abnormal knee joint mechanics associated with the development and progression of lateral knee OA after ACLR.

Reliability and minimal detectable change of gait kinematics in people who are hypermobile

ObjectiveTo evaluate intra- and inter-session reliability of gait data in hypermobile and normal adults, and from this, determine the minimum detectable change (MDC) through 3D gait analysis (GA) measurement. MethodsThirteen people with normal flexibility (Beighton score 0.82±1.2) and 14 hypermobile people (Beighton score 5.6±1.6) completed three separate GA sessions. Lower limb joint kinematics were recorded in three planes of motion. Intra- and inter-session variability was calculated and compared using single factor ANOVA. MDC at 95% confidence level was calculated for the hypermobile cohort. ResultsThere was no significant difference between hypermobile and normal flexibility adults in intra- or inter-session variability for any parameters measured. For both groups, mean intra-session variability was under 2.0° for all joints in all three planes. Inter-session variability was greater; sagittal plane joint angles were most reliable, showing less than 3.0° variability for all joints. Frontal plane variability was below 3.5°. Highest variability was seen in internal/external rotation angles, with hip, knee and ankle showing 4.6°, 5.1° and 3.2° variability respectively. These reliability values are reflected in MDC results, with pelvis and sagittal plane joint angles showing the lowest MDCs. ConclusionsIn hypermobile people, 3DGA kinematic parameters are repeatable. Hypermobile people's joint laxity does not affect variability of their kinematic gait analysis measures. The results will help guide future clinical trial design; future work should ensure that differences expected to be observed are measurable, and exceed the MDC for a given parameter.

Acute exposure to foot orthoses affects joint stiffness characteristics in recreational male runners

Commercially available foot orthoses are advocated for the treatment of chronic running injuries, such as patellofemoral pain, yet the mechanisms behind their effects are not well understood. This study aimed to examine the limb and joint stiffness characteristics when running with and without orthotics. Twelve recreational runners ran at 4.0 m/s. Limb stiffness was obtained using a spring-mass model of running by dividing the peak vertical ground reaction force (GRF) by the amount of limb compression. Knee and ankle joint stiffness’s were calculated by dividing the peak sagittal plane joint moment by the joint angular excursion. Differences between orthotic and non-orthotic running conditions were contrasted using paired samples t-tests. The results indicate that both peak knee extensor moment (orthotic = 2.74±0.57 and no-orthotic = 3.12±0.62 Nm/kg) and knee stiffness (orthotic = 5.56±1.08 and no-orthotic = 6.47±1.40 Nm/kg rad) were significantly larger when running without orthotics. This study may give further insight into the mechanical effects of commercially available foot orthoses. The current investigation provides some evidence to suggest that orthoses may be able to improve patellofemoral pathologies in recreational runners although further investigation is required.

Are clinical parameters sufficient to model gait patterns in patients with cerebral palsy using a multilinear approach?

The aim of this study was to evaluate whether clinical parameters are sufficient using, a multilinear regression model, to reproduce the sagittal plane joint angles (hip, knee, and ankle) in cerebral palsy gait. A total of 154 patients were included. The two legs were considered (308 observations). Thirty-six clinical parameters were used as regressors (range of motion, muscle strength, and spasticity of the lower). From the clinical gait analysis, the joint angles of the sagittal plane were selected. Results showed that clinical parameter does not provide sufficient information to recover joint angles and/or that the multilinear regression model is not an appropriate solution.

Kinematic, Cardiopulmonary, and Metabolic Responses of Overweight Runners While Running at Self-Selected and Standardized Speeds

ObjectiveTo determine the differences in kinematic, cardiopulmonary, and metabolic responses between overweight and healthy weight runners at a self-selected and standard running speed. DesignComparative descriptive study. SettingTertiary care institution, university-affiliated research laboratory. ParticipantsOverweight runners (n = 21) were matched with runners of healthy weight (n = 42). MethodsParticipants ran at self-selected and standardized speeds (13.6 km/h). Sagittal plane joint kinematics were captured simultaneously with cardiopulmonary and metabolic measures using a motion capture system and portable gas analyzer, respectively. Main Outcome MeasurementsSpatiotemporal parameters (cadence, step width and length, center of gravity displacement, stance time) joint kinematics, oxygen cost, heart rate, ventilation and energy expenditure. ResultsAt the self-selected speed, overweight individuals ran slower (8.5 ± 1.3 versus 10.0 ± 1.6 km/h) and had slower cadence (163 versus 169 steps/min; P < .05). The sagittal plane range of motion (ROM) for flexion-extension at the ankle, knee, hip, and anterior pelvic tilt were all less in overweight runners compared to healthy weight runners (all P < .05). At self-selected speed and 13.6 km/h, energy expenditure was higher in the overweight runners compared to their healthy weight counterparts (P < .05). At 13.6 km/h, only the frontal hip and pelvis ROM were higher in the overweight versus the healthy weight runners (P < .05), and energy expenditure, net energy cost, and minute ventilation were higher in the overweight runners compared to the healthy weight runners (P < .05). ConclusionAt self-selected running speeds, the overweight runners demonstrated gait strategies (less joint ROM, less vertical displacement, and shorter step lengths) that resulted in cardiopulmonary and energetic responses similar to those of healthy weight individuals.

Sit-to-stand biomechanics of individuals with multiple sclerosis

BackgroundIt is unclear how people with multiple sclerosis, who often have compromised strength and balance, compare to healthy controls during sit-to-stand movements. The purpose of this study was to compare sit-to-stand biomechanics among three groups: people with multiple sclerosis who exhibit leg weakness, people with multiple sclerosis who have comparable strength to controls, and healthy controls. MethodsTwenty-one individuals with multiple sclerosis (n=10 exhibiting leg weakness: n=11 exhibiting comparable strength to controls), and 12 controls performed five sit-to-stand trials while kinematic data and ground reaction forces were captured. ANOVAs followed by Tukey's post-hoc tests (α=0.05) were used to determine group and limb differences for leg strength, movement time, and sagittal-plane joint kinematics and kinetics. FindingsPersons with multiple sclerosis exhibiting leg weakness displayed decreased leg strength, greater trunk flexion, faster trunk flexion velocity and decreased knee extensor power compared to the other two groups (p<0.05; d≥0.87), and slower rise times compared to controls(p<0.03; d≥1.17). No differences were found between controls and the multiple sclerosis-comparable strength group. Across all 3 groups, leg strength was moderately correlated with trunk kinematics and knee extensor velocities, moments and powers of the sit-to-stand (p≤0.05). InterpretationParticipants with multiple sclerosis exhibiting leg weakness took longer to stand and appeared to use a trunk-flexion movement strategy when performing the sit-to-stand. The majority of group differences appear to be a result of leg extension weakness. Treatment that includes leg strengthening may be necessary to improve sit-to-stand performance for people with multiple sclerosis.