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Background Individuals with nonspecific chronic neck pain (NP) walk with a stiffer spine. However, there is a lack of understanding on kinematic similarities on the limbs during gait between individuals with and without NP. Research question Are there differences in gait parameters and the kinematic similarity index (SI) between individuals with and without NP? Methods Eighteen individuals with NP and 17 controls participated in this study. A three-dimensional motion capture system and two force plates were utilized to measure kinematic changes of the upper and lower limbs during gait. The gait parameters included cadence, speed, stride length, and step width. The SI calculations were compared based on the response vectors from the NP group and the prototype response vectors from the control participants. The SI values at 5% intervals of the entire gait cycle were compared between groups. Results Although the gait parameters were not significantly different between groups, the SI values of the control group were significantly higher than the NP group during gait (0.98 ± 0.02 vs. 0.95 ± 0.03), especially at the midstance (10–30 %) and swing (80–90 %) phases. Also, the standard deviation of the SI decreased in the control group when compared to the NP group (0.02 ± 0.01 vs. 0.04 ± 0.02). Significance The SI was a useful measure to differentiate similarities between groups in the gait cycle at specific phases. These results indicated that the NP group demonstrated a greater variation of walking patterns during the midstance and swing phases and displayed altered compensatory gait. Clinicians need to consider the similarities of the kinematic changes for the NP group to aid in detection of limb motion differences and the resulting gait dysfunction.

Gait speed is recognized to correlate to knee kinematic alterations. Clinically, patients with knee diseases tend to walk slowly compared to healthy controls. Hence, gait speed may serve as a confounding factor in the kinematic characteristics of patients during gait compared to healthy controls.Whether and how gait speed affects six degrees of freedom (6DOF) knee kinematics remains unclear. The current study was designed to explore whether and how decreased gait speeds affect 6DOF knee kinematics.Thirty subjects (15 males and 15 females) were recruited for this study. A three-dimensional gait analysis system was used to assess the 6DOF knee kinematics of subjects at gait speeds of 4.0 km/h, 3.5 km/h, 3.0 km/h, 2.5 km/h, 2.0 km/h, 1.5 km/h, and 1.0 km/h. Kinematics of gait cycle (GC) were assessed at all gait speed levels.Decreased adduction angle (0.5-3.2 °, p0.05), increased external rotation (0.6-3.3 °, p0.05) and decreased flexion angle (1.5-17.4 °, p0.05) were found during most GC as gait speed level decreased. Greater anterior tibial translation (0.9-2.6 mm, p0.05), greater proximal translation (0.4-2.4 mm, p0.05) and decreased lateral tibial translation (0.5-3.0 mm, p0.05) were found during most GC as gait speed level decreased. Gender was also found to have great effects on 6DOF knee kinematics (p0.05). Interactions between gender and gait speed were also found (p0.05).Our findings suggest that additional attention should be paid when dealing with kinematic comparisons of GC between controls and patients with significantly different gait speeds or genders than controls. Kinematic alterations induced by gait speed may raise concern for patients with knee diseases who struggle to walk faster than their normal speed. This may enhance our knowledge of the relationship between gait speed and 6DOF knee kinematics.

Background Dual Task (DT) paradigms are frequently used by researchers and clinicians to examine the integrity of motor processes in many movement disorders. However, the mechanism of this interaction is not fully understood. Therefore, the aim of this study was to examine the within-stride interactions between cognitive and motor processes during dual task gait (DT). Research question Do healthy young adults coordinate gait with secondary task processing? If so, is cognitive task processing capability associated with the coordination observed? Methods Nineteen healthy young adults walked for two minutes on a motorized treadmill whilst counting backwards in sevens from three-digit numbers. The coordination of calculation verbalizations with gait parameters were assessed across six phases of the gait cycle. Mid verbalization time points (VERMid) were used as points of high cognitive processing of the dual task and compared with the end of the verbalizations (VEREnd) as points of low cognitive processing. Results VERMid and VEREnd did not systematically occur in any phase of the gait cycle. However, 10/19 and 9/19 participants showed non-random distributions of verbalizations for VERMid and VEREnd time points respectively (p Significance It was found that cognitive processing is coordinated with gait phases in some but not all healthy young adults during DT gait. When demands on cognitive processes are high, healthy young adults coordinate cognitive processing with phases of gait. Analysis of within-stride coordination may be of use for studying clinical conditions where gait and attentional cognition performance breaks down.

Background Measuring gait function has become an essential tool in the assessment of mobility in aging populations for both, clinicians and researchers. A variety of systems exist that assess gait parameters such as gait cycle time, gait speed or duration of relative gait phases. Due to different measurement principles such as inertial or pressure sensors, accurate detection of spatiotemporal events may vary between systems. Research question To compare the absolute agreement and consistency in spatiotemporal gait parameters among five different clinical gait analysis systems using different sensor technologies. Methods We compared two devices using inertial sensors (GaitUp & Mobility Lab), two devices using pressure sensor systems (GAITRite & Zebris) as well as one optical system (OptoGait). Twelve older adults walked at self-selected speed through a walkway integrating all of the above systems. Basic spatiotemporal parameters (gait cycle time, cadence, gait speed and stride length) as well as measures of relative phase (stance phase, swing phase, double stance phase, single limb support) were extracted from all systems. We used Intraclass Correlation Coefficients as measures of agreement and consistency. Results High agreement and consistency between all systems was found for basic spatiotemporal parameters, whereas parameters of relative phase showed poorer agreement and consistency. Overground measurement (GAITRite & OptoGait) showed generally higher agreement with each other as compared to inertial sensor-based systems. Significance Our results indicate that accurate detection of both, the heel-strike and toe-off event are crucial for reliable results. Systematic errors in the detection of one or both events may only have a small impact on basic spatiotemporal outcomes as errors remain consistent from step to step. Relative phase parameters on the other hand may be affected to a much larger extent as these differences lead to a systematic increase or reduction of relative phase durations.

Background Children with static encephalopathy often walk with excessive knee and hip flexion throughout the gait cycle. This crouch gait pattern can be debilitating. These children may undergo hamstring-lengthening procedures to correct this crouch gait. Some improve, while others remain in crouch gait or go into knee hyperextension postoperatively, which can ultimately be debilitating. Research question Hamstring muscle-tendon length models are frequently used as indicators when making recommendations for or against hamstring lengthening procedures. According to the literature, most clinicians use the length of the hamstring complex at the initial contact phase of the gait cycle as the primary deciding factor. We hypothesize that the length of this muscle-tendon complex at the midstance phase of the gait cycle is a more stringent criteria for lengthening procedures. Methods A simplified hamstring length model was applied retrospectively to the pre and postoperative three dimensional gait analysis kinematics of 152 subjects to assess preoperative surgical indications and postoperative outcomes. Results Of the limbs with short hamstrings at initial contact preoperatively, 15% went into knee hyperextension following hamstring lengthening procedures. Cases of hyperextension were even higher (19%) if the hamstrings were also normal to long at midstance. If the hamstrings were short at midstance, only 6 % went into hyperextension. Increasing the criteria to short hamstrings at initial contact and midstance reduced the number of limbs with hyperextension to 0%. Significance It appears that the length of the hamstrings at midstance is an additional predictor of the risk of post-op knee hyperextension from hamstring lengthening procedures, than utilizing the length at initial contact alone. Even though short hamstrings at midstance may be an additional predictor of positive outcomes, it also results in a more conservative approach to surgery by excluding almost half of the patients with short hamstrings at initial contact only, but who may benefit from surgery.

Background The differences in anatomical structure between men and women are widely known. Unfortunately, the influence of gender on the biomechanics of a healthy knee joint during gait is still poorly understood. Research question The aim of the presented study was to determine loads acting in the knee joint during gait, based on the observation of a large group of healthy young adults, in particular to determine the influence of gender on values of forces and moments and their time characteristics during gait cycle. Methods Time-spatial gait parameters and ground reaction force were registered for 86 persons (43 females and 43 males) using a motion capture system and force plates. The numerical simulation with the AnyBody system was used to estimate loadings acting in the knee joint. Differences between women and men were tested using the unpaired Student's t-test with a Bonferroni correction. Results The maximum values of loadings acting in the knee joint were: 411.1 %BW (body weight) for resultant force, 390.6 %BW for proximo-distal force, 110.8 %BW for antero-posterior force, 77.0 %BW for medio-lateral force, 2.63 %BWh (body weight times height) for flexion/extension moment, 0.97 %BWh for internal/external rotation moment and 5.7 %BWh for abduction/adduction moment. In general, the normalised forces were greater in the male group, while the normalised external moments acting on the knee were greater in the female group. Local extrema of forces during the stance phase were observed earlier for women. Significance Knowledge about gender differences in loadings acting in the knee joint can be of great importance in the case of detecting the early stages of gait abnormalities and treatment planning.

Background Gait event detection (GED) is an important aspect in identifying and interpret a user’s gait to assess gait abnormalities and design intelligent assistive devices. Research question There is a need to develop robust GED models that can accurately detect various gait instances in different scenarios and environments. Methods This paper presents a novel method of detecting heel strikes (HS) and toe offs (TO) during the user’s gait cycle using a modified Long Short-Term Memory (LSTM) networks approach. The method was tested on a database from Movement Analysis in Real-world Environments using Accelerometers (MAREA) (n = 20 healthy subjects) that consisted of walking and running in indoor and outdoor environments with accelerometers positioned on waist, wrist and both ankles. Modifications include oversampling, composite accelerations and optimizing the LSTM network architecture were made. Results Performance of our modified model was found to be better than six state-of-the-art GED algorithms, with a median F1 score of 0.98 for Heel Strikes and 0.98 for Toe Offs in the scenario of steady walking in an indoor environment, and a median F1 score of 0.94 for Heel Strikes and 0.68 for Toe-offs in the scenario of walking and running in an outdoor environment. Significance This paper highlights the potential of the single proposed model to be an alternative to the six GED models in gait detection under various conditions.

Background: Robotic rehabilitation has been attracting attention as a means to carry out "intensive", "repetitive", "task-specific", gait training. The newly developed robotic device, the Hybrid Assistive Limb (HAL), is thought to have the possibility of having an excellent effect on gait speed improvement over the conventional automatic programed assist robot. The purpose of this study was to investigate the spatiotemporal characteristics related to gait speed improvement using the HAL in chronic stroke patients. Research question: To investigate the effects of robotic gait training on gait speed and gait parameters. Methods: An observational study with an intervention for single group was used. Intervention was conducted in University Hospital. Eleven chronic stroke patients were enrolled in this study. The patients performed 8 gait training sessions using the HAL, 2–5 sessions/week for 3 weeks. Gait speed, stride length, cadence, time of gait cycle (double-limb stance phases and single-limb stance phases) and time asymmetry index were measured before and after intervention. Results: After intervention, gait speed, stride length, and cadence were significantly improved (Effect size = 0.39, 0.29, and 0.29), the affected initial double-limb stance phase was significantly shortened (from 15.8 ± 3.46%–13.3 ± 4.20%, p = .01), and the affected single-limb stance phase was significantly lengthened (from 21.8±7.02%–24.5±7.95%, p

Background: Chronic ankle instability (CAI) has previously been linked to altered lower limb kinematics and muscle activation characteristics during walking, though little research has been performed analysing the full time-series across the stance and swing phases of gait. Research question: The aim of this study was to compare trunk and lower limb kinematics and muscle activity between those with chronic ankle instability and healthy controls. Methods: Kinematics and muscle activity were measured in 18 (14 males, 4 females) healthy controls (age 22.4 ± 3.6 years, height 177.8 ± 7.6 cm, mass 70.4 ± 11.9 kg, UK shoe size 8.4 ± 1.6), and 18 (13 males, 5 females) participants with chronic ankle instability (age 22.0 ± 2.7 years, height 176.8 ± 7.9 cm, mass 74.1 ± 9.6 kg, UK shoe size 8.1 ± 1.9) during barefoot walking trials, using a combined Helen Hayes and Oxford foot model. Surface electromyography (sEMG) was recorded for the tibialis anterior and gluteus medius. Full curve statistical parametric mapping was performed using independent and paired-samples T-tests. Results: No significant differences were observed in kinematic or sEMG variables between or within groups for the duration of the swing phase of gait. A significantly increased forefoot-tibia inversion was seen in the CAI affected limb when compared to the CAI unaffected limb at 4-16% stance (p = 0.039). No other significant differences were observed. Significance: There appears to be no differences in muscle activation and movement between CAI and healthy control groups. However, participants with CAI exhibited increased inversion patterns during the stance phase of gait in their affected limb compared to their unaffected limb. This may predispose those with CAI to episodes of giving way and further ankle sprains.

Computational methods to estimate muscle forces during walking are becoming more common in biomechanical research but not yet in clinical gait analysis. This systematic review aims to identify the current state-of-the-art, examine the differences between approaches, and consider applicability of the current approaches in clinical gait analysis.\ud A systematic database search identified studies including estimated muscle force profiles of the lower limb during healthy walking. These were rated for quality and the muscle force profiles digitised for comparison.\ud From 13.449 identified studies, 22 were finally included which used four modelling approaches: static optimisation, enhanced static optimisation, forward dynamics and EMG-driven. These used a range of different musculoskeletal models, muscle-tendon characteristics and cost functions. There is visually broad agreement between and within approaches about when muscles are active throughout the gait cycle. There remain considerable differences (CV 7% to 151%, range of timing of peak forces in gait cycle 1% to 31%) in patterns and magnitudes of force between and within modelling approaches.\ud The main source of this variability is not clear. Different musculoskeletal models, experimental protocols, and modelling approaches will clearly have an effect as will the variability of joint kinetics between healthy individuals. Limited validation of modelling approaches, particularly at the level of individual participants, makes it difficult to conclude if any of the approaches give consistently better estimates than others.\ud While muscle force modelling has clear potential to enhance clinical gait analyses future research is needed to improve validation, accuracy and feasibility of implementation in clinical practice.

Understanding the effects of leg length discrepancy (LLD) on the biomechanics of gait and determining as to what extent of LLD alters gait is essential. A total of 91 biomechanical data were assessed from 14 lower limbs of healthy individuals walking under random conditions: shod only and with a 5, 10, 15, 20, 30 and 40 mm sole lift. Lower limb kinematics and dynamic leg length (DLL) were measured by a motion capture system. Hotelling's T-Square test was used to evaluate the differences in DLLs throughout the gait cycle in conjunction with differences between the sides based on the maximal stance phase and minimal swing phase DLLs. Kinematics were compared using the one-way blocked analysis of variance and Post-hoc analysis by the paired t-test. Significant dynamic shortening of the longer limb, mainly during the swing phase, and significant change in maximal stance and minimal swing phase DLL relationship started at a 10 mm lift condition (p 0.05). Thirteen kinematic variables produced a significant angular main effect (p 0.05), with a more flexed position of the longer limb and extended shorter limb beginning at a 5 mm lift. An increase in hip abduction and external foot rotation during the swing phase was also found. This study demonstrates that simulated LLD, as low as 5 mm, causes biomechanical changes in the lower limbs during gait revealed in both kinematics and dynamic leg length, suggesting that LLD, as small as 5-10 mm, should not be ignored.

The research purpose was to quantify the co-contraction patterns of quadriceps femoris (QF) vs. hamstring muscles during free walking, in terms of onset-offset muscular activation, excitation intensity, and occurrence frequency. Statistical gait analysis was performed on surface-EMG signals from vastus lateralis (VL), rectus femoris (RF), and medial hamstrings (MH), in 16315 strides walked by 30 healthy young adults. Results showed full superimpositions of MH with both VL and RF activity from terminal swing, 80 to 100% of gait cycle (GC), to the successive loading response (≈0–15% of GC), in around 90% of the considered strides. A further superimposition was detected during the push-off phase both between VL and MH activation intervals (38.6 ± 12.8% to 44.1 ± 9.6% of GC) in 21.9 ± 13.6% of strides, and between RF and MH activation intervals (45.9 ± 5.3% to 50.7 ± 9.7 of GC) in 32.7 ± 15.1% of strides. These findings led to identify three different co-contractions among QF and hamstring muscles during able-bodied walking: in early stance (in ≈90% of strides), in push-off (in 25–30% of strides) and in terminal swing (in ≈90% of strides). The co-contraction in terminal swing is the one with the highest levels of muscle excitation intensity. To our knowledge, this analysis represents the first attempt for quantification of QF/hamstring muscles co-contraction in young healthy subjects during normal gait, able to include the physiological variability of the phenomenon.

Despite the high number of studies evaluating the outcomes following tibial shaft fractures, the literature lacks studies including objective assessment of patients' recovery regarding gait pattern. The purpose of the present study was to evaluate whether gait patterns at 6 and 12 months post-operatively following intramedullary nailing of a tibial shaft fracture are different compared with a healthy reference population.The study design was a prospective cohort study. The primary outcome measurement was the gait patterns at 6 and 12 months post-operatively measured with a 6-metre-long pressure-sensitive mat. The mat registers footprints and present gait speed, cadence as well as temporal and spatial parameters of the gait cycle. Gait patterns were compared to a healthy reference population.49 patients were included with a mean age of 43.1 years (18-79 years). Forty-three patients completed the 12-month follow-up (88%). Gait speed and cadence were significantly increased between the 6- and 12-month follow-up (P0.001). At 6-month follow-up, patients showed considerable asymmetry in the injured leg compared with the non-injured leg: single-support time 12.8% shorter, swing-time 12.8% longer, step-length 11.9% shorter, and rotation of the foot increased by 32.3%. At the 12-month follow-up, gait asymmetry become almost normalized compared to a healthy reference group.In patients treated by intramedullary nailing following a tibial shaft fracture, gait asymmetry accompanied with slower speed and cadence are common during the first 6 months and become normalized compared with a healthy reference population between 6 and 12 months post-operatively.

Gait parameters variability and falls are problems for persons with MS and have not been adequately captured in the home. Our goal was to explore the feasibility and acceptability of monitoring of gait and falls in the homes of persons with MS over a period of 30 days. To test the feasibility of measuring gait and falls for 30days in the home of persons with MS, spatiotemporal gait parameters stride length, stride time, and gait speed were compared. A 3D infrared depth imaging system has been developed to objectively measure gait and falls in the home environment. Participants also completed a 16-foot GaitRite electronic pathway walk to validate spatiotemporal parameters of gait (gait speed (cm/s), stride length (cm), and gait cycle time(s)) during the timed 25 foot walking test (T25FWT). We also documented barriers to feasibility of installing the in-home sensors for these participants. The results of the study suggest that the Kinect sensor may be used as an alternative device to measure gait for persons with MS, depending on the desired accuracy level. Ultimately, using in-home sensors to analyze gait parameters in real time is feasible and could lead to better analysis of gait in persons with MS.

The gait cycle is frequently divided into two distinct phases, stance and swing, which can be accurately determined from ground reaction force data. In the absence of such data, kinematic algorithms can be used to estimate footstrike and toe-off. The performance of previously published algorithms is not consistent between studies. Furthermore, previous algorithms have not been tested at higher running speeds nor used to estimate ground contact times. Therefore the purpose of this study was to both develop a new, custom-designed, event detection algorithm and compare its performance with four previously tested algorithms at higher running speeds. Kinematic and force data were collected on twenty runners during overground running at 5.6m/s. The five algorithms were then implemented and estimated times for footstrike, toe-off and contact time were compared to ground reaction force data. There were large differences in the performance of each algorithm. The custom-designed algorithm provided the most accurate estimation of footstrike (True Error 1.2 ± 17.1 ms) and contact time (True Error 3.5 ± 18.2 ms). Compared to the other tested algorithms, the custom-designed algorithm provided an accurate estimation of footstrike and toe-off across different footstrike patterns. The custom-designed algorithm provides a simple but effective method to accurately estimate footstrike, toe-off and contact time from kinematic data.

Background Gait deviations due to increased femoral antetorsion have been described in the literature and it was recommended to consider three-dimensional gait analysis for clinical decision making. Sagittal plane gait deviations were, however, only described for the pelvis and hip so far. Research question Therefore, the purpose of this study was to identify deviations in sagittal plane gait kinematics and kinetics caused by increased femoral antetorsion. Methods Patients with isolated, CT confirmed increased femoral antetorsion (n = 42, 59 limbs) and age-matched healthy controls (n = 17, 32 limbs) were included for this study. Kinematic and kinetic data were recorded during three-dimension gait analysis. Sagittal plane lower extremity kinematics were analyzed for three valid gait cycles. Principal component (PC) analysis was used as exploratory step to achieve data transformation. A linear mixed model was used to estimate the group effect of PC-scores of retained PCs explaining 90% of the cumulative variance. Results Group effects of PC-scores revealed that patients walked with more flexed hips and greater anterior pelvic tilt throughout the gait cycle. Knee flexion was increased in patients during mid and terminal stance and plantar flexion was decreased in pre and initial swing. Significance We showed alterations in all lower limb joints and therefore 3D gait analysis should be used for clinical decisions making. In the future, operative treatment should be considered depending on severity of gait deviations.

This study compares the pattern and variability of inter-joint coordination between treadmill and overground walking. Gait analyses of five young adults were performed during preferred speed overground walking (GPS), preferred speed treadmill walking (TPS), and treadmill walking with overground preferred speed (TGS). Continuous relative phase (CRP), derived from the phase portraits of two adjacent joints, was used to examine the inter-joint coordination. Cross-correlation measures and root-mean-square (RMS) differences were used to compare CRP patterns of the GPS condition to those of TPS and TGS conditions respectively. The deviation phase (DP) was used to evaluate the variability of inter-joint coordination during the stance and swing phases over a gait cycle for each condition. The walking speed of TPS was significantly slower than those of GPS and TGS. For the hip-knee CRP pattern, the RMS differences between GPS and TPS were significantly greater than the RMS differences between GPS and TGS. No significant differences between conditions were detected for the cross-correlation measures of hip-knee and knee-ankle CRP patterns. During the stance phase, the hip-knee DP values of TGS were significantly smaller than that of GPS and the knee-ankle DP values of TGS were also significantly smaller than that of GPS and TPS. No significant differences were detected for all three conditions in the swing phase. The findings suggest that the treadmill imposes a systemic regulation on dynamic neuromuscular control during walking, which may need to be considered while interpreting treadmill-based analysis of training to overground walking.

A B S T R A C T Crouch gait decreases walking efficiency due to the increased knee and hip flexion during the stance phase of gait. Crouch gait is generally considered to be disadvantageous for children with cerebral palsy; however, a crouched posture may allow biomechanical advantages that lead some children to adopt a crouch gait. To investigate one possible advantage of crouch gait, a musculoskeletal model created in OpenSim was placed in 15 different postures from upright to severe crouch during initial, middle, and final stance of the gait cycle for a total of 45 different postures. A series of optimizations was performed for each posture to maximize transverse plane ground reaction forces in the eight compass directions by modifying muscle forces acting on the model. We compared the force profile areas across all postures. Larger force profile areas were allowed by postures from mild crouch (for initial stance) to crouch (for final stance). The overall ability to generate larger ground reaction force profiles represents a mechanical advantage of a crouched posture. This increase in muscle capacity while in a crouched posture may allow a patient to generate new movements to compensate for impairments associated with cerebral palsy, such as motor control deficits.

Running with a step rate 5-10% greater than one's preferred can substantially reduce lower extremity joint moments and powers, and has been suggested as a possible strategy to aid in running injury management. The purpose of this study was to examine how neuromuscular activity changes with an increase in step rate during running. Forty-five injury-free, recreational runners participated in this study. Three-dimensional motion, ground reaction forces, and electromyography (EMG) of 8 muscles (rectus femoris, vastus lateralis, medial gastrocnemius, tibialis anterior, medial and lateral hamstrings, and gluteus medius and maximus) were recorded as each subject ran at their preferred speed for three different step rate conditions: preferred, +5% and +10% of preferred. Outcome measures included mean normalized EMG activity for each muscle at specific periods during the gait cycle. Muscle activities were found to predominantly increase during late swing, with no significant change in activities during the loading response. This increased muscle activity in anticipation of foot-ground contact likely alters the landing posture of the limb and the subsequent negative work performed by the joints during stance phase. Further, the increased activity observed in the gluteus maximus and medius suggests running with a greater step rate may have therapeutic benefits to those with anterior knee pain.

In complete spinal cord injured (cSCI) subjects a shift from dominant early (60–120 ms latency) to dominant late (120–450 ms latency) spinal reflex (SR) components occurs over time after injury. This shift is assumed to reflect a spinal neuronal dysfunction below the level of a spinal lesion. The neuronal pathways of SR are suggested to be closely connected with spinal locomotor circuits. The aim of this study was to explore the influence of the two SR components on the electromyographic (EMG) pattern induced by assisted locomotion in cSCI subjects. Leg muscle EMG activity was analysed during assisted locomotion in both healthy and motor cSCI subjects. SR were evoked by non-noxious tibial nerve stimulation during mid-stance phase of the gait cycle. Early and late SR components had a differential influence on the locomotor pattern. In healthy and cSCI subjects with a dominant early SR component the locomotor EMG pattern was modulated in the form of a short increase in leg flexors activity in the stance phase (tibialis anterior, biceps femoris). In contrast, in chronic cSCI subjects with a dominant late SR component no activation in biceps femoris but a long-lasting activation of tibialis anterior and rectus femoris muscles during the stance phase was evoked. It is concluded that the same tibial nerve stimuli activated two different neuronal pathways, resulting in divergent interactions with spinal locomotor circuitries. It is proposed that the two SR components have different physiological roles during locomotion.

The purpose of this study was to investigate the pattern and variability of inter-joint coordination for both surgical and non-surgical limbs during walking in patients before and after total hip arthroplasty (THA). Gait analysis of THA patients ( n = 20) and age-matched controls ( n = 10) was performed. THA patients were tested at pre-surgery, 6-week and 16-week post surgery. Continuous relative phase (CRP) was used to assess the inter-joint coordination pattern and variability. Variability of coordination for each subject was calculated over a gait cycle with the deviation phase (DP). Between-subject group differences in CRP patterns were examined with cross-correlation measures and root-mean-square (RMS) differences. The surgical limb demonstrated significantly higher DP values comparing to the controls at pre-surgery. Compared to pre-surgery, significant time effects on THA patients were detected in hip–knee DP values at 16-week post surgery for both limbs, and in knee–ankle DP values at 16-week post surgery for the surgical limb. RMS differences for hip–knee and knee–ankle CRP decreased gradually after surgery for both limbs. Cross-correlation measures were overall strong for CRP patterns of both limbs, with r 2 values greater than 0.94. Our results suggested that both hip–knee and knee–ankle coordination, especially the surgical limb, were altered with a higher variability to compromise the deteriorated hip joint. Asymmetric changes in accommodations and variability of bilateral lower extremities may contribute to the residual gait problems observed in THA patients. Therefore, clinical efforts may exert to improve the inter-joint coordination in this population.

This study investigates whether the spatio-temporal parameters of gait in the elderly vary as a function of walking distance. The gait pattern of older subjects (n = 27) over both short (SWD 20 in) walking was evaluated using an ambulatory device consisting of body-worn sensors (Physilog"). The stride velocity (SV), gait cycle time (GCT), and inter-cycle variability of each parameter (CV) were evaluated for each subject, Analysis was undertaken after evaluating the errors and the test-retest reliability of the Physilog device compared with an electronic walkway system (GaitRite ")over the SWD with different walking speeds. While both systems were highly reliable with respect to the SV and GCT parameters (ICC > 0.82), agreement for the gait variability was poor. Interestingly, Our data revealed that the measured gait parameters over SWD and LWD were significantly different. LWD trials had a mean increase of 5.2%(p

Abnormalities in gait kinematics in persons with multiple sclerosis (PwMS) who have mild disability have been noted using motion capture systems. However, it is not clear if these abnormalities can be detected with clinically feasible technology. This investigation examined if the spatiotemporal markers of gait including variability metrics can distinguish between PwMS with minimal disability and controls with clinically feasible technology. 43 PwMS with minimal disability and 43 healthy controls completed four walking trials along a 26 foot long pressure sensitive pathway (GAITRite). Spatiotemporal markers of gait including variability metrics were determined. Statistical analysis revealed that PwMS walked slower, with fewer, shorter, wider steps and spent a greater percentage of a gait cycle in double support than controls. Additionally, PwMS had greater variability in the time between steps, single support percent and step width than controls. Collectively, the results highlight that PwMS, in the absence of clinical gait impairment, have subtle but detectable differences in gait and that these alterations can be detected with clinically feasible technology. The current results raise the possibility of targeting walking deviations earlier in disability progression in PwMS.

A force-plate instrumented treadmill (Hp Cosmos Gaitway) was used to validate the use of a miniaturised lightweight ear-worn sensor (7.4 g) for gait monitoring. Thirty-four healthy subjects were asked to progress up to their maximum walking speed on the treadmill (starting at 5 km/h, with 0.5 km increments). The sensor houses a 3D accelerometer which measures medio-lateral (ML), vertical (VT) and anterior–posterior (AP) acceleration. Maximum signal ranges and zero crossings were derived from accelerometer signals per axis, having corrected for head motion and signal noise. The maximal force, measured by the instrumented treadmill correlated best with a combination of VT and AP acceleration (R-squared = 0.36, p = 0), and combined VT, ML, and AP acceleration (R-squared = 0.36, p = 0). Weight-acceptance peak force and impulse values also correlated well with VT and AP acceleration (Weight acceptance: R-squared = 0.35, p = 0, Impulse: 0.26, p = 0), and combined VT, ML, and AP acceleration (Weight acceptance: R-squared = 0.35, p = 0, Impulse: 0.26, p = 0). Zero crossing features on the ML axis provided an accurate prediction of the gait-cycle, with a mean difference of 0.03 s (−0.01, 0.05 confidence intervals).

It has been proposed that the highly reproducible forward walking (FW) locomotor pattern is generated by a central neuronal program or central pattern generator (CPG) which provides the underlying mechanism which produces the coordinated walking movement. The purpose of this study was to quantify the differences in the muscular activation patterns during FW and backward walking (BW) at a constant step frequency and to determine if common features exist across both locomotor conditions. The hypothesis was that FW and BW are both mediated by the same CPG; therefore, only small modifications in the CPG are required in order to produce the different characteristics of each walking mode. The results noted kinematically reversed patterns at the hip and ankle joints between FW and BW. The knee joint movement pattern was similar between conditions, however, a phase shift of 14.3% of the gait cycle occurred. An approximately 25% phase shift in the muscle activation patterns existed between FW and BW in four of the six muscles studied. Additionally, a pattern recognition technique was applied to the combined EMG signals to determine the minimum number of features required to generate the measured muscular output. Only two main features were necessary to produce the EMG patterns for both the FW and BW condition. The main features in FW were more consistent than noted in BW. The results support the notion that a single spinal mechanism such as a CPG with two main features appears to be in control during both FW and BW. Copyright 1998 Elsevier Science B.V. All rights reserved

5. Results Significant increases in stride length (p = 0.0004) and step length (p < 0.0001) of 9 and 5 cm, respectively, were found in walking with shoes in children with CP. Only two significant changes in the kinematics were found: a decrease in minimum hip flexion during stance of 2 ◦ (p = 0.0001) and an increase in the range of motion of 3 ◦ at the hip (p = 0.002). The mean EMG amplitude and the level of coactivation over a gait cycle were not significantly different between the two conditions.

The paper investigates the consistency of EMG recordings of gait obtained in three different laboratories using a standardised measurement technique. Ensemble averaged surface EMG profiles were recorded in rectus femoris, semitendinosus, tibialis anterior, and gastrocnemius medialis muscles in a group of 20 normal subjects who walked at comfortable walking speed. Each subject was studied in three separate laboratories and the data were compared. Experimental protocols and electromyographic instrumentation were standardised, and functionally equivalent footswitch systems were used. Consistency of the shape of the subjects' profiles across laboratories was described using correlation coefficients. The signal magnitudes were compared using the coefficient of variation and mean value of profiles. The across-laboratory inter-subject variability was determined for peak, onset and cessation times of EMG activity. A marked similarity in the shape of profiles across laboratories was found. Times of peak, onset and cessation of EMG activity were repeatable within few percent of the gait cycle. The absolute magnitude of the profiles was less consistent. The results of this study suggest that meaningful exchange of EMG data amongst laboratories for multi-centre trials and teleconsultation purposes is possible. The study underlines the value of EMG recording as a tool in gait analysis. It is concluded that standardisation of instrumentation, experimental protocols and data processing techniques is strongly needed.

Patellofemoral pain syndrome is a frequent knee impairment in young adults. This study investigated the kinematic and kinetic gait patterns of individuals suffering from patellofemoral pain syndrome (PFPS). It was hypothesized that PFPS subjects modify their gait pattern in order to reduce loading on the painful patellofemoral joint. To verify this, the gait pattern of five subjects with right chronic PFPS was compared with that of five healthy subjects. Spatiotemporal, kinematic and kinetic data were collected from five gait cycles. The joint moments at the hip, knee and ankle joints were calculated using an inverse dynamic approach and the values were normalized to body weight (N·m/kg). Individual joint moments were expressed as a percentage of the support moment in order to quantify possible compensatory strategies. The kinematic analysis revealed a significant reduction of the knee flexion angle (ANOVAs, P 0.05) as far as the individual joint moments and their contribution to the support moment were concerned. However, modifications were observed in the knee and hip moments between 10% and 20% of the gait cycle. These modifications may suggest that PFPS subjects alter their gait pattern in order to reduce loading of the patellofemoral joint to avoid pain.

Vertical ground reaction forces were measured in 20 hemiplegic stroke patients with a wearable footprint analysis system to characterize patterns varying with severity of involvement. Dynamic, temporal-related and time-distance parameters were obtained from a gait sequence of about 25 s. The severity of involvement seemed to determine stride length and walking velocity (P ≤ 0.001). Although the hemiplegic side showed time support interval shortening (P < 0.01) and major alterations in reception and propulsion dynamics with decreased force values (P < 0.05), it remained nearly constant and apparently independent of the degree of involvement. Most of the differences concerned the non-hemiplegic side which seemed to provide more useful information about the evolution of the function. The implications of these results on the general approach of the pathology are discussed.

An experimental ankle-foot orthosis of which the flexibility and the initial angle of the ankle joint can be changed arbitrarily was made to assess the effect of mechanical property of ankle-foot orthoses on the hemiplegic gait. Gait of 15 hemiplegic patients was measured continuously using the experimental ankle-foot orthosis, and the data were analysed statistically. Results showed that assistive dorsiflexion moment adequate to the individual patient's disability at the time of the initial foot contact improves the gait of the hemiplegic patient throughout the whole gait cycle.

Space and time gait parameters can be estimated with wearable inertial units. Linear displacement information is typically obtained by double integrating accelerometer data over each gait cycle. However, usually a drift affects the resulting displacement signals and therefore its effects should be minimized. In the majority of studies using accelerometers, drift is corrected on the hypothesis that during the stance phase, the velocity of the sensor placed on the foot is zero. This assumption allows to set to zero the estimated velocity at both the beginning and the end of the gait cycle. Despite the use of the latter hypothesis is crucial for the drift correction, to the authors’ knowledge, no quantitative validation of this hypothesis is available in the literature. This study aimed at determining the velocity profiles of various points of the foot during the stance phase of the gait cycle while walking at different speeds.

s of the SIAMOC 2008 Congress / Gait & Posture 29S (2009) e1–e31 e15 Subjects andmethods: Ten childrenwith CPI (5with emiplegia and 5 with diplegia) were recruited consecutively for this study, mean age 5.6 1.9 years (3–9 years)mean bodyweight kg 19.7 6.7 and mean height 109.3 11.5 cm. They underwent pharmacological treatment with BoNT-A for the presence of overactivity of plantarflexor muscles. Parents gave their informed approval to the participation of their children to this study. The EMG activity of distalmuscles of lower limbswas recorded during the performance of four experimental tasks: (1) walking over ground, at a self-selected velocity, (2) walking at a pre-selected velocity, over a treadmill, (3) walking at a pre-selected velocity, over an inclined treadmill and (4) climbing stairs. Surface EMG activity of m. tibialis anterior and m. gastrocnemius was recorded by a wireless electromyograph (band pass of 10–350 Hz, frequency of sampling 1000 Hz). The temporospatial gait parameters were measured by foot-switches. Evaluations were performed before the administration of BoNT-A and 4, 8, 16weeks after. The dose of BoNT-A injected in the calf muscles was of 15 U/kg of Dysport (Ipsen) for limb. After the acquisition, the EMG signalwas rectified, integrated and normalized to the gait cycle and to the cycle of stair climbing. The mean values of EMG activity were obtained from 10 gait cycles and from 5 cycles of stair climbing. Results: The qualitative evaluation of activation patterns of m. gastronemius, 4, 8, 16 weeks after administration of BoNT-A, shows the presence of a flattening of the typical overactive EMG profile recorded before drug. The quantitative evaluation, 4 weeks after the administration of BoNT-A, shows a reduction of mean EMG activation values in respect to those recorded before BoNT-A, in all four experimental tasks, but mainly during walking over a treadmill (walking over ground 44.3 48.5%; walking over treadmill 63.9 10.9%; walking over an inclined treadmill 47.5 22.6%; stair climbing 49.8 20.2%). The effects of BoNTA lasted for 16 weeks in most of children, even if they were progressively less pronounced. Discussion: The administration of BoNT-A in the m. gastrocnemius caused amarked reduction of the EMG overactivity, in the group of children reported in this study. This effect is still present 16 week after administration of BoNT-A. Walking over a treadmill, at a pre-selected velocity, seems to allow a better control of experimental conditions and a better evaluation of the effects of BoNT-A, by minimizing the influence of laboratory setting on the behaviour of children.