Average Cadence Research Articles

A Switched Lyapunov-Passivity Approach to Motorized FES Cycling Using Adaptive Admittance Control

For individuals with neuromuscular disorders (NDs) affecting the coordination and control of their legs, motorized functional electrical stimulation (FES) cycling serves as a rehabilitation strategy and offers numerous health benefits. A motorized FES cycle is an example of a hybrid exoskeleton involving cooperative physical human–robot interaction where both the cycle’s motor and rider’s muscles (through electrical stimulation) must be controlled to achieve desirable performance. A robust sliding-mode cadence controller is developed for the rider’s muscles, while an adaptive admittance controller is employed on the cycle’s motor to preserve rider comfort and safety. A switched systems stability analysis using Lyapunov and passivity-based methods is conducted to ensure global asymptotic stability of the admittance error system and that the cadence error system remains passive. Experiments are conducted on one able-bodied participant and four participants with NDs to illustrate the performance of the control design. For the participants with NDs, the controller achieved an average admittance tracking error of −0.08±1.05 rpm at an average cadence of 47.85±1.13 rpm for the desired cadence of 50 rpm.

Robust Cadence Tracking for Switched FES-Cycling With an Unknown Time-Varying Input Delay

For an individual affected by a neuromuscular condition (NC), functional electrical stimulation (FES)-induced cycling provides a means of functional restoration and therapeutic exercise. Although FES-cycling has been shown to have numerous benefits, there are challenges to implementing closed-loop FES control for coordinated motion. For example, there exists a potentially destabilizing input delay between the application (or removal) of stimulation and the resulting muscle force. Moreover, switching between multiple actuators (such as FES or motor control) can also be destabilizing. This brief develops delay-dependent switching conditions and a robust control method to account for an unknown time-varying input delay of a switched system. A Lyapunov-like analysis is performed to yield semiglobal exponential cadence tracking to an ultimate bound. Experiments were performed on six able-bodied participants and four participants with NCs to validate the developed controller. The proposed controller resulted in an average cadence error of 0.01 ± 2.00 revolutions per minute (RPM) for the able-bodied participants and 0.01 ± 2.72 RPM for participants with NCs.

Passive Knee Orthoses Assistance in Functional Electrical Stimulation Cycling in an Individual With Spinal Cord Injury

Functional Electrical Stimulation (FES) may be used in rehabilitation and assistance of people with Spinal Cord Injury (SCI). One significant application is facilitating physical exercise, mainly when combining FES with mechanical platforms, such as tricycles. However, there are still technical challenges in FES cycling protocols, such as improving control and cycling performance. Here we show how passive elements in knee orthoses during FES cycling could increase the average cadence, taking advantage of the cycling movement. Our approach is twofold. First, we simulated the forward dynamics of a detailed musculoskeletal model with passive elements over the knees. Simulations showed that specific spring stiffness ranges increased the crankset speed during cycling by more than 50%. Using parameters found in simulations, we built a pair of passive orthoses and performed experiments with one individual with SCI. During two days, the volunteer cycled with similar stimulation magnitude with and without the passive elements. We observed that the average crankset speed was higher by more than 10% when the springs were attached to the passive orthoses. These results show the potential of using passive elements to increase cycling speed for FES cycling with similar or even lower stimulation magnitude, leading to longer exercise duration.

Associations Between Neurochemistry and Gait Performance Following Concussion in Collegiate Athletes.

To evaluate the strength of associations between single-task and dual-task gait measures and posterior cingulate gyrus (PCG) neurochemicals in acutely concussed collegiate athletes. Participants were recruited from an NCAA Division 1 University. Nineteen collegiate athletes acutely (<4 days) following sports-related concussion. We acquired magnetic resonance spectroscopy (MRS) in the PCG and gait performance measurements in the participants, acutely following concussion. Linear mixed-effects models were constructed to measure the effect of gait performance, in the single- and dual-task settings, and sex on the 6 neurochemicals quantified with MRS in mmol. Correlation coefficients were also calculated to determine the direction and strength of the relationship between MRS neurochemicals and gait performance, postconcussion symptom score, and number of previous concussions. Average gait speed, average cadence, N-acetyl aspartate, choline, myo-inositol, glutathione, glutamate plus glutamine, and creatine. Single-task gait speed (P = .0056) and cadence (P = .0065) had significant effects on myo-inositol concentrations in the PCG, independent of sex, in concussed collegiate athletes. Single-task cadence (P = .047) also had a significant effect on glutathione in the PCG. No significant effects were observed between dual-task gait performance and PCG neurochemistry. These findings indicate that increased concentrations of neuroinflammatory markers in the PCG are associated with slower single-task gait performance within 4 days of sports-related concussion.

Changes In Dual-task Gait Speed Following A 10-week Golf Program In Older Adults

PURPOSE: To examine the change in dual-tasking ability during gait in response to a golf exercise program in healthy, older adults. BACKGROUND: The ability of older adults to perform dual-tasking during gait has been studied as a predictor of fall risk. Therefore, it is important to investigate exercise programs that not only improve fitness and balance in older adults, but also enhance the ability to dual-task. METHODS: Fifteen healthy, older adults without previous golf experience were enrolled in a golf program with fitness testing before and after the intervention. One participant had to drop out of the study due to a work-related injury at week 8. Dual-task performance was measured using a fast-gait task while counting backwards by threes on a ProtokineticsTM walking mat. Cognitive cost was determined by normalizing the dual-task responses to a seated counting task. Paired t tests were run to determine significance. Results are presented as mean±SD. Cohen’s d effect sizes were calculated and reported as small=0.2, medium=0.5, and large=0.8. RESULTS: Gait speed during the dual-task was significantly increased following the golf program with a large effect size (1.75±0.19m/s to 1.91±0.22m/s; p=0.007; d=0.85). This increase in gait speed coincided with increases in both average stride length (2.3%; p=0.061; d=0.55) and average cadence (5.8%; p=0.059; d=0.55). Cognitive dual cost did not change between pre and post testing but trended towards improving (40.94%; p=0.207; d=0.35). CONCLUSION: Golf is a unique, multimodal activity that has a beneficial impact on fitness in healthy, older adults. This study demonstrated that a golf program can improve the ability to perform dual tasking. Participants were able to increase their gait speed without compromising the amount of numbers they could recite correctly. The participants trended towards an improved correct response rate following the program as shown by the improvement in cognitive dual cost. Golf should be encouraged as a physical activity program for older adults. Supported by R&A Grant GHA0012017.

A new approach toward gait training in patients with Parkinson’s Disease

BackgroundTypically, people with Parkinson’s Disease (PD) progress to develop a gait pattern that is characterized by quick, short and shuffling steps. Gait cycle is altered and lacks definition and fluidity. Gait training combined with a variety of feedback modalities for PD are usually based on non-immediate and externally-based cues but none of these provide real-time feedback on gait quality and acquired gains tend to abate shortly after rehabilitation. Based on principals of motor learning, our team has developed the Heel2Toe sensor to provide real-time auditory feedback during gait training. Research questionIs a short-term training using the Heel2Toe sensor feasible and efficient to improve gait in people with PD? Our objectives are to identify the extent of the immediate response to the feedback within the same session and the carry-over response to training and; 2) to identify patients’ perceived effects, pleasures and challenges of using the Heel2Toe. MethodsSingle-arm, proof-of-concept study. Six people received five sessions of gait training over a 2–3-week period using the Heel2Toe augmented with mobility exercises as an adjunct to gait training. The main outcomes were technically assessed gait parameters collected over a 2-minute walk test, without and with feedback. Heel2Toe signals were analyzed to extract angular velocity(AV), percentage of good steps, average cadence, and AV coefficient of variation(CV). ResultsAn immediate response to the Heel2Toe use and a carry-over response to the short-term training with the sensor were observed: an increase in AV with a reduction in CV (better heel strike and gait regularity); an increase in %good steps; and a near-optimal and homogeneous cadence (∼100 steps/min), which is equivalent to a moderate-intensity walking. SignificanceGait training using the Heel2Toe sensor is feasible and potentially effective for improving gait quality in people with PD. A definitive trial is a logical next step.

Oxygen Consumption While Walking With Multijoint Neuromuscular Electrical Stimulation After Stroke

This case study evaluated the effect of implanted multijoint neuromuscular electrical stimulation gait assistance on oxygen consumption relative to walking without neuromuscular electrical stimulation after stroke. The participant walked slowly with an asymmetric gait pattern after stroke. He completed repeated 6-min walk tests at a self-selected walking speed with and without hip, knee, and ankle stimulation assistance. His walking speed with neuromuscular electrical stimulation more than doubled from 0.28 ± 0.01 m/sec to 0.58 ± 0.04 m/sec, whereas average step length and cadence increased by 0.12 m and 24 steps/min, respectively. As a result, energy cost of walking with neuromuscular electrical stimulation decreased by 0.19 ml O2/kg per meter as compared with walking without stimulation while oxygen consumption increased by 1.1 metabolic equivalent of tasks (3.9 ml O2/kg per minute). These metabolic demands are similar to those reported for stroke survivors capable of walking at equivalent speeds without stimulation, suggesting the increase in oxygen consumption and decreased energy cost result from improved efficiency of faster walking facilitated by neuromuscular electrical stimulation. Although the effect of neuromuscular electrical stimulation on gait economy has implications for community walking within the user's metabolic reserves, this case study's results should be interpreted with caution and the hypothesis that multijoint neuromuscular electrical stimulation improves metabolic efficiency should be tested in a wide population of stroke survivors with varied deficits.

The haemodynamic demand and the attributes related to the displacement of the soccer referees in the moments of decision / intervention during the matches

ABSTRACT The present study aimed to analyze the hemodynamic variables and the displacement variables, the former being heart rate (meanHR), maximum heart rate (maxHR) and minimum heart rate (HRmin), and the latter being average speed (Vmed), maximum speed (Vmax), mean cadence and distance traveled during referee interventions in matches of the Brazilian national football league. 1224 observable decisions of 10 professional soccer referees from Rio de Janeiro were analyzed. Three moments were considered: the moment of decision (D0), the 15 seconds that preceded it (D15), and the period from the beginning of each step to the decision (DA). It was observed a high hemodynamic load in the moments analyzed. The meanHR in the 10 matches was 160.5±8.33, the results showed very high maxHR values, the highest value found was 222bpm. Regarding the comparison between the halves of the game: 1st half (1st) and 2nd half (2nd), the initial stage of the matches, requires more intense displacements with lower hemodynamic pressure. The results suggest that cognitive decision making influences hemodynamic variables. Apparently, in the second stage of the matches, due to the accumulation of exercise demanded in the previous stage, the referees adopted a condition of saving of energy.

Torque and cadence tracking in functional electrical stimulation induced cycling using passivity-based spatial repetitive learning control

Due to the inherent periodic nature of cycling tasks, iterative and repetitive learning controllers are well motivated for rehabilitative cycling. Motorized functional electrical stimulation induced cycling is a rehabilitation treatment where multiple lower-limb muscle groups are activated jointly with an electric motor to achieve cycling objectives such as speed (cadence) and torque tracking. This paper examines torque tracking accomplished by the stimulation of six lower-limb muscles via a novel spatial repetitive learning control and cadence regulation by an electric motor using a sliding-mode controller. A desired torque trajectory is constructed based on the rider’s kinematic efficiency, which is a function of the crank position. The learning controller takes advantage of the periodicity of the desired torque trajectory to provide a feedforward input to the stimulated muscles. A passivity-based analysis is developed to ensure stability of the torque and cadence closed-loop error systems. The muscle learning and electric motor controllers were implemented in real-time during cycling experiments on five able-bodied individuals and three participants with movement disorders. The combined average cadence tracking error was 0.01±1.20 RPM for a 50 RPM trajectory and the combined average power tracking error was 1.78±1.25 W for a peak power of 10 W.

Performance comparison in the Wingate test between standing and seated positions in competitive cyclists

Abstract Aims: The current study aimed to compare the anaerobic power output through the Wingate test in different positions, i.e., standing and seated, and identify the relationship between power-output and body mass. Methods: Eleven male competitive cyclists (age: 30.3 ± 4.7 years; body mass: 73.7 ± 7.7 kg; body fat: 11.3 ± 4.2%) were submitted to two sessions of the Wingate test (WT) in different positions, on different days. Results: The peak power (W), average power (W), relative peak power (W·kg-1), relative average power (W·kg-1), average cadence (rpm), and average velocity (km·h-1) presented significant differences in the standing position compared with the seated position (p 0.05). The fatigue and peak heart rate (bpm) indices did not present significant differences between the tests (p > 0.05). Conclusions: Sprint performance was improved when the WT was performed in a standing position in competitive cyclists. The study also reports the important relationship between body mass and anaerobic production capacity in the WT, emphasizing that it is desirable an increase in lean body mass and a reduction in fat mass, similar in competitions. We suggest that, for anaerobic assessment in cyclists, the standing position should be used during the WT, to determine the maximum power-output capacity.

The performance of photometric reverberation mapping at high redshift and the reliability of damped random walk models

ABSTRACT Accurate methods for reverberation mapping using photometry are highly sought after since they are inherently less resource intensive than spectroscopic techniques. However, the effectiveness of photometric reverberation mapping for estimating black hole masses is sparsely investigated at redshifts higher than z ≈ 0.04. Furthermore, photometric methods frequently assume a damped random walk (DRW) model, which may not be universally applicable. We perform photometric reverberation mapping using the javelin photometric DRW model for the QSO SDSS-J144645.44+625304.0 at z = 0.351 and estimate the Hβ lag of $65^{+6}_{-1}$ d and black hole mass of $10^{8.22^{+0.13}_{-0.15}}\, \mathrm{M_{\odot }}$. An analysis of the reliability of photometric reverberation mapping, conducted using many thousands of simulated CARMA process light curves, shows that we can recover the input lag to within 6 per cent on average given our target’s observed signal-to-noise of &amp;gt;20 and average cadence of 14 d (even when DRW is not applicable). Furthermore, we use our suite of simulated light curves to deconvolve aliases and artefacts from our QSO’s posterior probability distribution, increasing the signal-to-noise on the lag by a factor of ∼2.2. We exceed the signal-to-noise of the Sloan Digital Sky Survey Reverberation Mapping Project (SDSS-RM) campaign with a quarter of the observing time per object, resulting in a ∼200 per cent increase in signal-to-noise efficiency over SDSS-RM.

The Seoul National University AGN Monitoring Project. II. BLR Size and Black Hole Mass of Two AGNs

Abstract Active galactic nuclei (AGNs) show a correlation between the size of the broad line region and the monochromatic continuum luminosity at 5100 Å, allowing black hole mass estimation based on single-epoch spectra. However, the validity of the correlation is yet to be clearly tested for high-luminosity AGNs. We present the first reverberation mapping results of the Seoul National University AGN Monitoring Project (SAMP), which is designed to focus on luminous AGNs for probing the high end of the size–luminosity relation. We report time lag measurements of two AGNs, namely, 2MASS J10261389+5237510 and SDSS J161911.24+501109.2, using the light curves obtained over an ∼1000 days period with an average cadence of 10 and 20 days, respectively, for photometry and spectroscopy monitoring. Based on a cross-correlation analysis and Hβ line width measurements, we determine the Hβ lag as 41.8 − 6.0 + 4.9 and 52.6 − 14.7 + 17.6 days in the observed frame, and black hole mass as 3.65 − 0.57 + 0.49 × 10 7 M ⊙ and 23.02 − 6.56 + 7.81 × 10 7 M ⊙ , respectively, for 2MASS J1026 and SDSS J1619.

Closed-Loop Cadence and Instantaneous Power Control on a Motorized Functional Electrical Stimulation Cycle

Motorized functional electrical stimulation (FES) cycling is a rehabilitation therapy in which electrical stimulation is used to activate lower body muscles to pedal a cycle in conjunction with motorized assistance. FES cycling has been demonstrated to improve cardiovascular parameters, muscle mass, and motor control of people with neurological conditions (NCs). A common FES cycling objective is simultaneous cadence and power (torque) tracking; however, it is unclear how to best coordinate the FES and motor contributions and if power should be tracked instantaneously or averaged over a period of time. This article develops a new FES cycling controller using a switched Lyapunov-like dwell-time analysis for the nonlinear, uncertain cycling system to conclude global exponential cadence tracking and uniformly ultimately bounded power tracking. To evaluate the performance of the developed controller, comparisons are made with two previously developed FES cycling controllers through experiments on seven able-bodied participants and six participants with NCs. For a desired cadence of 50 RPM and a desired power of 10 W, the developed controller demonstrated the smallest tracking errors with an average cadence and power error of 0.01±1.03 RPM and 0.00±0.94 W, respectively, in the able-bodied population and an average cadence and power error of 0.02±1.87 RPM and 0.00±2.46 W, respectively, in the population of people with NCs. Results suggest that the electric motor should be used to track cadence and the FES induced muscle torques should be used to track instantaneous power.

Passivity-Based Iterative Learning Control for Cycling Induced by Functional Electrical Stimulation With Electric Motor Assistance

This brief examines the use of a learning control method in a passivity-based framework to control a motorized cycle-rider system with functional electrical stimulation (FES) of the quadriceps muscle groups. FES cycling with motorized assistance has been used in the rehabilitation of people with neurological conditions. The concepts of adaptation and passivity are explored to compensate for the uncertain nonlinear time-varying dynamics of the motorized FES cycle-rider system. The system is modeled as a closed-loop feedback, state-dependent switched system such that in each cycle, the quadriceps muscle groups produce the functional torque and the electric motor provides assistance as needed. The output strictly passive feature of the closed-loop system is proven by considering a learning control input. Then, an adaptive update law, based on iterative learning control, is developed to guarantee the convergence of the cadence tracking error. Experimental results from seven able-bodied participants are presented and discussed to demonstrate the effectiveness of this approach. The average cadence tracking error is 0.00 ± 2.47 rpm for the desired trajectory of 50 rpm.

Determining the utility of a smartphone-based gait evaluation for possible use in concussion management

ABSTRACTObjectives: Our was objectives were to (1) assess the validity of a smartphone-based application to obtain spatiotemporal gait variables relative to an established movement monitoring system used previously to evaluate post-concussion gait, and (2) determine the test-retest reliability of gait variables obtained with a smartphone.Methods: Twenty healthy participants (n = 14 females, mean age = 22.2, SD = 2.1 years) were assessed at two time points, approximately two weeks apart. Two measurement systems (inertial sensor system, smartphone application) acquired and analyzed single-task and dual-task spatio-temporal gait variables simultaneously. Our primary outcome measures were average walking speed (m/s), cadence (steps/min), and stride length (m) measured by the inertial sensor system and smartphone application.Results: Correlations between the systems were high to very high (Pearson r = 0.77–0.98) at both time points, with the exception of dual-task stride length at time 2 (Pearson r = 0.55). Bland-Altman analysis for average gait speed and cadence indicated the average disagreement between systems was close to zero, suggesting little evidence for systematic bias between acquisition systems. Test-retest consistency measures using the smartphone revealed high to very high reliability for all measurements (ICC = 0.81–0.95).Conclusions: Our results indicate that sensors within a smartphone are capable of measuring spatio-temporal gait variables similar to a validated three-sensor inertial sensor system in single-task and dual-task conditions, and that data are reliable across a two-week time interval. A smartphone-based application might allow clinicians to objectively evaluate gait in the management of concussion with high ease-of-use and a relatively low financial burden.

Validity of an instrumented sock and on-shoe sensor to provide biometric feedback to runners

Study Design: Validity study.Background: Run form analysis and retraining are commonly utilized in orthopaedic and sports medicine environments. New tools in running technology may assist clinicians in providing feedback to runners outside the clinic. These devices provide runners the capacity to analyse multiple characteristics of their stride, but little is known regarding the accuracy of their output.Objective: Investigate the validity of an instrumented sock and on-shoe sensor as compared to high-speed video analysis.Methods: Forty recreational runners completed a 10-minute treadmill run at a self-selected pace while wearing both devices. High-speed video allowed for the analysis of average running cadence and percentage of time in each foot strike pattern. Other variables of interest included running speed and distance. Intraclass correlation coefficients (ICC2,1) were calculated for all variables. A categorical classification of dominant foot strike pattern was utilized, with Cohen’s kappa describing agreement of the devices to video analysis.Results: The instrumented sock’s ICCs were 0.40 for speed, 0.46 for distance, 0.97 for cadence and 0.40 for foot strike pattern. The on-shoe sensor generated ICCs of 0.86 for speed, 0.86 for distance, 0.99 for cadence and 0.91 for foot strike pattern. Cohen’s kappa values for foot strike pattern agreement were 0.35 for the sock and 0.79 for the on-shoe sensor.Conclusion: The instrumented sock demonstrated valid measurement of running cadence, but potential product design limitations reduced accuracy on the other study variables. The on-shoe sensor utilized in this study provided valid post-run feedback across measures of speed, distance, cadence and dichotomous classification of foot strike pattern.

Опыт использования открытых данных спортивной социальной сети для анализа результатов Московского марафона 2017 года

Objective: to explore the possibilities of sport social network open data in analysis of Moscow Marathon 2017 (MM2017) results. Materials and methods: open data, downloaded from sport gadgets to Strava.com social network by 1165 of 7972 MM2017 participants were retrieved (information about sex, age, race time, average heart rate (HR) and cadence at the race, and training intensity). Results: the age of participants was 34 (30-39) years, 13% of women, women were significantly younger than men. The median of the race time was 4:31:56 for women, 4:03:11 for men, p = 0.0001; the average cadence was 174 and 169 respectively, p = 0.0001; average HR was 163 and 162 respectively, p = 0.07. There was no correlation between age and race time, at least for runners under 60 years. The total distance, the number and duration of trainings in 2017 and 2016, personal bests at distances 5-42.2 km did not differ significantly in men and women, but were higher in participants with over-median race time and over-median age. Average HR and average cadence of participants with under-median race time was significantly higher than in those with over-median race time (163 and 161 bpm, p = 0.002; 174 and 166 per minute, p = 0.0001 respectively). The average HR was expectedly higher in younger participants (164 and 160 bpm, p <0.0001). The average cadence in runners divided by the median of age was not significantly different. Analysis of average time in pulse zones showed that participants with better race time were able to maintain higher HR for longer time, what can be considered to more intense training. Conclusions: the open data of Strava.com users can enrich mass running analytics, limited before by age, sex and the race time of participants. The availability of information about the average HR, cadence at the race and training intensity can improve the research possibilities in sports medicine. This data can be useful instrument of coaching.

Do Older Adults Achieve Moderate Intensity When Walking At Their Self-selected Pace?

Walking at a cadence of ≥100 steps/min consistently corresponds to minimally moderate intensity physical activity (PA). While current PA guidelines emphasize the importance of PA intensity for positive health outcomes, most young adults already naturally walk at cadences ≥100 steps/min. It is unknown whether older adults select these same cadences and intensities when they freely select their walking pace. PURPOSE: To determine cadence and intensity of self-paced walking in older adults, and to evaluate the accuracy of using ≥100 steps/min to indicate moderate intensity in this population. METHODS: Twenty-six healthy, ambulatory older adults (10M,16W; mean±SD; age=68.3±4.8 years; height=1.67±.08 m; mass=73.4±12.3 kg) walked continuously for 5min at their self-selected pace back and forth along a 13m pathway that included a 7m gait mat. Oxygen uptake (VO2; mL/kg/min) was determined using indirect calorimetry and converted to absolutely-defined metabolic equivalents (METs; VO2/3.5). Average cadence was quantified using the gait mat. Prevalence of cadences ≥100 and METs ≥3 was calculated as the number of participants above the respective thresholds divided by total participants (n=26). Classification Accuracy (ACC; true positive + true negative / total participants) determined the accuracy of ≥100 steps/min indicating ≥3 METs. RESULTS: The majority of participants (23/26, 83.3%) walked at a cadence ≥100 steps/min (cadence=113±9 steps/min), and many (20/26, 76.9%) achieved moderate intensity (METs=3.43±0.59). A cadence of ≥100 steps/min was a strong indicator of moderate intensity during self-paced walking (i.e., ≥3 to <6 METs, ACC = 80.8%). CONCLUSION: Most healthy older adults attain at least moderate metabolic intensity during self-paced walking. These findings further suggest that “going for a walk” can be recommended, even in the absence of specific PA intensity guidelines. However, these results are preliminary and include only healthy, ambulatory, and relatively young (i.e., only one participant >75 years old) older adults. Future studies should continue to explore self-paced walking in a more representative sample of older adults, and include more of the oldest adults (i.e., >75 years), or those with disease or ambulatory limitations. FUNDING:NIH-NIA-5R01AG049024

Kinematic and Kinetic Waveform Changes of the Knee Joint Following a Mobile Bearing Total Knee Arthroplasty-Gait Analysis and Single Step Ascent.

The objective of this study is to analyze the kinetic and kinematic changes of the osteoarthritic knee after a mobile bearing total knee arthroplasty. Kinematic and kinetic gait analysis of level walking was performed in 15 patients (eight female and seven male) with knee ostoarthritis. All patients were free of any neurological diseases that could affect their normal gait. Mean age was 68.6 ± 5.2 years, mean height 159.8 ± 6.9 cm, and mean weight was 78.5 ± 10.1 kg. Full body gait analysis was performed using the BioKin three-dimensional (3D) motion analysis system preoperatively and 9 months after total knee arthroplasty. A single-step ascending kinetic analysis and a plantar pressure distribution analysis were also performed in all patients. An increased average cadence (mean 99.39 step/min preoperatively and 104.64 step/min postoperatively; p = 0.152), step length (0.44 m preoperatively and 0.52 m postoperatively; p < 0.001), stride length (0.89 m preoperatively and 1.0 m postoperatively; p < 0.007), and walking velocity (0.73 m/sec preoperatively and 0.90 m/sec postoperatively; p = 0.005) were noted postoperatively and postoperatively. A decrease in the stance duration percentage and the knee adduction moment was also reported postoperatively. All patients showed a significant improvement of knee kinetics and kinematics after a mobile bearing total knee arthroplasty. Statistically significant differences were found in the step length, stride length, and walk velocity postoperatively. The knee adduction moment was also significantly reduced. Further research is warranted to determine the clinical relevance of these findings. This study is a prospective comparative one and reflects level II evidence.

Sagittal subtalar and talocrural joint assessment between barefoot and shod walking: A fluoroscopic study

BackgroundWhile wearing shoes is common in daily activities, most foot kinematic models report results on barefoot conditions. It is difficult to describe foot position inside shoes. This study used fluoroscopic images to determine talocrural and subtalar motion. Research QuestionWhat are the differences in sagittal talocrual and subtalar kinematics between walking barefoot and while wearing athletic walking shoes? MethodsThirteen male subjects (mean age 22.9 ± 2.9 years, mean weight 77.2 ± 6.9 kg, mean height 178.2 ± 3.7 cm) screened for normal gait were tested. A fluoroscopy unit was used to collect images during stance. Sagittal motion of the talocrural and subtalar joints of the right foot were analyzed barefoot and in an athletic walking shoe. ResultsShod talocrural position at heel strike was 6.0° of dorsiflexion and shod peak talocrural plantarflexion was 4.2°. Barefoot talocrural plantarflexion at heel strike was 4.2° and barefoot peak talocrural plantarflexion was 10.9°. Shod subtalar position at heel strike was 2.6° of plantarflexion and peak subtalar dorsiflexion was 1.5°. The barefoot subtalar joint at heel strike was in 0.4° dorsiflexion and barefoot peak subtalar dorsiflexion was 3.5°. As the result of wearing shoes, average walking speed and stride length increased and average cadence decreased. Comparing barefoot to shod walking there was a statistical significance in talocrural dorsiflexion and at heel strike and peak talocrural dorsiflexion, subtalar plantarflexion at heel strike and peak subtalar dorsiflexion, walking speed, stride length, and cadence. SignificanceThis work demonstrates the ability to directly measure talocrural and subtalar kinematics of shod walking using fluoroscopy. Future work using this methodology can be used to increase understanding of hindfoot kinematics during a variety of non-barefoot activities.