scholarly journals Genetic Algorithms Based Approach for Designing Spring Brake Orthosis – Part I: Spring Parameters

2012 ◽  
Vol 9 (3) ◽  
pp. 303-316 ◽  
Author(s):  
M. S. Huq ◽  
M. O. Tokhi
Keyword(s):  
First Principles ◽  
Knee Flexion ◽  
Gait Cycle ◽  
Sagittal Plane ◽  
Swing Phase ◽  
Full Extension ◽  
Torsion Spring ◽  
Constant Torque ◽  
Spring Type ◽  
Hip Flexion

Spring brake orthosis (SBO) concentrates purely on the knee to generate the swing phase of the paraplegic gait with the required hip flexion occurring passively as a consequence of the ipsilateral knee flexion, generated by releasing the torsion spring mounted at the knee joint. Electrical stimulation then drives the knee back to full extension, as well as restores the spring potential energy. In this paper, genetic algorithm (GA) and its variant multi-objective GA (MOGA) is used to perform the search operation for the ‘best’ spring parameters for the SBO spring mounted on an average sized subject simulated in the sagittal plane. Conventional torsion spring is tested against constant torque type spring in terms of swing duration as, based on first principles, it is hypothesized that constant torque spring would be able to produce slower SBO swing phase as might be preferred in assisted paraplegic gait. In line with the hypothesis, it is found that it is not possible to delay the occurrence of the flexion peak of the SBO swing phase further than its occurrence in the natural gait. The use of conventional torsion spring causes the swing knee flexion peak to appear rather faster than that of the natural gait, resulting in a potentially faster swing phase and hence gait cycle. The constant torque type spring on the other hand is able to stretch duration of the swing phase to some extent, rendering it the preferable spring type in SBO.

Constraining movement reveals motor capability in chronic stroke: an initial study

2016 ◽  
Vol 31 (8) ◽  
pp. 1126-1133 ◽  
Author(s):  
Clarisa A Martinez ◽  
Emily Mintz ◽  
Andrea E Ecsedy ◽  
Beth E Fisher
Keyword(s):  
Knee Flexion ◽  
Sagittal Plane ◽  
Step Length ◽  
Initial Study ◽  
Swing Phase ◽  
Chronic Stroke ◽  
Task Demands ◽  
Treadmill Walking ◽  
Gait Kinematics ◽  
Hip Flexion

Objective: To determine if persons with chronic stroke and decreased hip and knee flexion during swing can walk with improved swing-phase kinematics when the task demands constrained gait to the sagittal plane. Design: A one-day, within-subject design comparing gait kinematics under two conditions: Unconstrained treadmill walking and a constrained condition in which the treadmill walking space is reduced to limit limb advancement to occur in the sagittal plane. Setting: Outpatient physical therapy clinic. Subjects: Eight individuals (mean age, 64.1 ±9.3, 2 F) with mild-moderate paresis were enrolled. Main measures: Spatiotemporal gait characteristics and swing-phase hip and knee range of motion during unconstrained and constrained treadmill walking were compared using paired t-test and Cohen’s d ( d) to determine effect size. Results: There was a significant, moderate-to-large effect of the constraint on hip flexion ( p < 0.001, d = –1.1) during initial swing, and hip ( p < 0.05, d = –0.8) and knee ( p < 0.001, d = –1.1) flexion during midswing. There was a moderate effect of constraint on terminal swing knee flexion ( p = 0.238, d = –0.6). Immediate and significant changes in step width ( p < 0.05, d = 0.9) and paretic step length ( p < 0.05, d = –0.5) were noted in the constrained condition compared with unconstrained. Conclusion: Constraining the treadmill walking path altered the gait patterns among the study’s participants. The immediate change during constrained walking suggests that patients with chronic stroke may have underlying movement capability that they do not preferentially utilize.

scholarly journals Sagittal Plane Hip, Knee, and Ankle Biomechanics and the Risk of Anterior Cruciate Ligament Injury: A Prospective Study

2017 ◽  
Vol 5 (12) ◽  
pp. 232596711774548 ◽  
Author(s):  
Mari Leppänen ◽  
Kati Pasanen ◽  
Tron Krosshaug ◽  
Pekka Kannus ◽  
Tommi Vasankari ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Acl Injury ◽  
Young Female ◽  
Roc Curve Analysis ◽  
Acl Injuries ◽  
Increased Risk ◽  
Flexion Moment ◽  
Hip Flexion

Background: Stiff landings with less knee flexion and high vertical ground-reaction forces have been shown to be associated with an increased risk of anterior cruciate ligament (ACL) injury. The literature on the association between other sagittal plane measures and the risk of ACL injuries with a prospective study design is lacking. Purpose: To investigate the relationship between selected sagittal plane hip, knee, and ankle biomechanics and the risk of ACL injury in young female team-sport athletes. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 171 female basketball and floorball athletes (age range, 12-21 years) participated in a vertical drop jump test using 3-dimensional motion analysis. All new ACL injuries, as well as match and training exposure data, were recorded for 1 to 3 years. Biomechanical variables, including hip and ankle flexion at initial contact (IC), hip and ankle ranges of motion (ROMs), and peak external knee and hip flexion moments, were selected for analysis. Cox regression models were used to calculate hazard ratios (HRs) with 95% CIs. The combined sensitivity and specificity of significant test variables were assessed using a receiver operating characteristic (ROC) curve analysis. Results: A total of 15 noncontact ACL injuries were recorded during follow-up (0.2 injuries/1000 player-hours). Of the variables investigated, landing with less hip flexion ROM (HR for each 10° increase in hip ROM, 0.61 [95% CI, 0.38-0.99]; P < .05) and a greater knee flexion moment (HR for each 10-N·m increase in knee moment, 1.21 [95% CI, 1.04-1.40]; P = .01) was significantly associated with an increased risk of ACL injury. Hip flexion at IC, ankle flexion at IC, ankle flexion ROM, and peak external hip flexion moment were not significantly associated with the risk of ACL injury. ROC curve analysis for significant variables showed an area under the curve of 0.6, indicating a poor combined sensitivity and specificity of the test. Conclusion: Landing with less hip flexion ROM and a greater peak external knee flexion moment was associated with an increased risk of ACL injury in young female team-sport players. Studies with larger populations are needed to confirm these findings and to determine the role of ankle flexion ROM as a risk factor for ACL injury. Increasing knee and hip flexion ROMs to produce soft landings might reduce knee loading and risk of ACL injury in young female athletes.

scholarly journals The mechanism of hamstring injuries – a systematic review

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Adam Danielsson ◽  
Alexandra Horvath ◽  
Carl Senorski ◽  
Eduard Alentorn-Geli ◽  
William E. Garrett ◽  
...  
Keyword(s):  
Systematic Review ◽  
Kinematic Analysis ◽  
Gait Cycle ◽  
Swing Phase ◽  
Injury Mechanism ◽  
Hamstring Injury ◽  
Cochrane Library ◽  
Level Of Evidence ◽  
Hamstring Injuries ◽  
Hip Flexion

Abstract Background Injuries to the hamstring muscles are among the most common in sports and account for significant time loss. Despite being so common, the injury mechanism of hamstring injuries remains to be determined. Purpose To investigate the hamstring injury mechanism by conducting a systematic review. Study design A systematic review following the PRISMA statement. Methods A systematic search was conducted using PubMed, EMBASE and the Cochrane Library. Studies 1) written in English and 2) deciding on the mechanism of hamstring injury were eligible for inclusion. Literature reviews, systematic reviews, meta-analyses, conference abstracts, book chapters and editorials were excluded, as well as studies where the full text could not be obtained. Results Twenty-six of 2372 screened original studies were included and stratified to the mechanism or methods used to determine hamstring injury: stretch-related injuries, kinematic analysis, electromyography-based kinematic analysis and strength-related injuries. All studies that reported the stretch-type injury mechanism concluded that injury occurs due to extensive hip flexion with a hyperextended knee. The vast majority of studies on injuries during running proposed that these injuries occur during the late swing phase of the running gait cycle. Conclusion A stretch-type injury to the hamstrings is caused by extensive hip flexion with an extended knee. Hamstring injuries during sprinting are most likely to occur due to excessive muscle strain caused by eccentric contraction during the late swing phase of the running gait cycle. Level of evidence Level IV

scholarly journals Movement of the tibial end in a PTB prosthesis socket: A sagittal X-ray study of the PTB prosthesis

1993 ◽  
Vol 17 (1) ◽  
pp. 21-26 ◽  
Author(s):  
M. Lilja ◽  
T. Johansson ◽  
T. Öberg
Keyword(s):  
Gait Cycle ◽  
Soft Tissues ◽  
Sagittal Plane ◽  
Mean Value ◽  
Swing Phase ◽  
Patient Comfort ◽  
X Ray ◽  
Prosthetic Socket ◽  
Heel Contact ◽  
Prosthetic Fitting

To investigate the movement of the tibial end in the sagittal plane in the PTB prosthetic socket during a gait cycle, 7 patients with a median age of 72 years were examined using X-ray technique. The gait cycle was reduced to four different static positions: heel contact, mid-stance, push-off and swing phase. The mean value of tibial movement in the socket in the anteroposterior direction was 2.2 cm, in proximodistal direction 2.8 cm, and the total sagittal movement during the whole gait cycle was 7.5 cm. The results indicate that one factor affecting the magnitude of the movement was the prestretching of soft tissues. All the patients who experienced a good prosthetic fitting had their soft tissues prestretched. The extreme dorsal and proximal positions of the tibial end during the gait cycle was in the swing phase position. The extreme distal position occurred somewhere between mid-stance and push-off. The extreme anterior position of the tibial end was seen during heel contact. This study has shown the magnitude of the movements in a PTB socket during a simulated gait cycle. The study has given hints on factors affecting prosthetic fitting, and further research within this field might provide indications of how to optimise socket shape to give maximal patient comfort.

Ankle Bracing Alters Coordination and Coordination Variability in Individuals With and Without Chronic Ankle Instability

2021 ◽  
Vol 30 (1) ◽  
pp. 62-69
Author(s):  
Adam E. Jagodinsky ◽  
Christopher Wilburn ◽  
Nick Moore ◽  
John W. Fox ◽  
Wendi H. Weimar
Keyword(s):  
Lower Extremity ◽  
Gait Cycle ◽  
Relative Phase ◽  
Sagittal Plane ◽  
Ankle Instability ◽  
Chronic Ankle Instability ◽  
Swing Phase ◽  
Coordination Dynamics ◽  
Ankle Brace ◽  
Ankle Bracing

Context: Ankle bracing is an effective form of injury prophylaxis implemented for individuals with and without chronic ankle instability, yet mechanisms surrounding bracing efficacy remain in question. Ankle bracing has been shown to invoke biomechanical and neuromotor alterations that could influence lower-extremity coordination strategies during locomotion and contribute to bracing efficacy. Objective: The purpose of this study was to investigate the effects of ankle bracing on lower-extremity coordination and coordination dynamics during walking in healthy individuals, ankle sprain copers, and individuals with chronic ankle instability. Design: Mixed factorial design. Setting: Laboratory setting. Participants: Forty-eight recreationally active individuals (16 per group) participated in this cross-sectional study. Intervention: Participants completed 15 trials of over ground walking with and without an ankle brace. Main Outcome Measures: Coordination and coordination variability of the foot–shank, shank–thigh, and foot–thigh were assessed during stance and swing phases of the gait cycle through analysis of segment relative phase and relative phase deviation, respectively. Results: Bracing elicited more synchronous, or locked, motion of the sagittal plane foot–shank coupling throughout swing phase and early stance phase, and more asynchronous motion of remaining foot–shank and foot–thigh couplings during early swing phase. Bracing also diminished coordination variability of foot–shank, foot–thigh, and shank–thigh couplings during swing phase of the gait cycle, indicating greater pattern stability. No group differences were observed. Conclusions: Greater stability of lower-extremity coordination patterns as well as spatiotemporal locking of the foot–shank coupling during terminal swing may work to guard against malalignment at foot contact and contribute to the efficacy of ankle bracing. Ankle bracing may also act antagonistically to interventions fostering functional variability.

Analysis of locomotor adaptations in young children with limb loss in an early prosthetic knee prescription protocol

2013 ◽  
Vol 38 (1) ◽  
pp. 54-61 ◽  
Author(s):  
Mark Geil ◽  
Colleen Coulter
Keyword(s):  
Young Children ◽  
Knee Flexion ◽  
Knee Prosthesis ◽  
Swing Phase ◽  
Clinical Protocols ◽  
Full Extension ◽  
Walking Gait ◽  
Prosthetic Knee ◽  
Before And After ◽  
Locomotor Adaptations

Background: Traditionally, clinical protocols for the treatment of young children who require a knee prosthesis have favored stability, with the prosthetic knee locked into full extension until after the child has learned to walk. Recently, an Early Knee protocol has been investigated, in which children receive an articulating knee in their first prosthesis and use it while learning to crawl and walk. Objectives: This study investigated the presence of swing phase clearance adaptations in the walking gait of seven young children aged 18–92 months, who had been fitted according to the Early Knee protocol. Study design: Before-and-after experimental design. Methods: Each subject completed walking trials with the knee freely flexing and trials with the knee locked into full extension to mimic a traditional knee protocol. Results: Subjects utilized the articulating knee in walking, with an average of 70.4° of peak swing phase knee flexion. Some clearance adaptations were present with the flexing knee; more were present and their magnitude was increased when the knee was locked. In particular, there was a statistically significant increase in circumduction. Conclusions: These results suggest that the Early Knee protocol can reduce the adoption of clearance adaptations while walking is developing. Clinical relevance Treatment of young children who require a knee prosthesis is inconsistent. Traditionally, no knee is provided until independent walking is achieved. A newer Early Knee protocol provides an articulating knee in the first prosthesis. This study found that children use the articulating knee in walking and develop fewer clearance adaptations.

scholarly journals Outdoor walking exhibits peak ankle and knee flexion differences compared to fixed and adaptive-speed treadmills in older adults

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Sheridan M. Parker ◽  
Jeremy Crenshaw ◽  
Nathaniel H. Hunt ◽  
Christopher Burcal ◽  
Brian A. Knarr
Keyword(s):  
Older Adults ◽  
Knee Flexion ◽  
Walking Speed ◽  
Sagittal Plane ◽  
Measurement Unit ◽  
Adult Participants ◽  
Peak Knee ◽  
Outdoor Walking ◽  
Hip Flexion ◽  
Walking Speeds

Abstract Background Walking mechanics recorded with a traditional treadmill may not be the same as the mechanics exhibited during activities of daily living due to constrained walking speeds. Adaptive-speed treadmills allow for unconstrained walking speeds similar to outdoor walking. The aim of this study was to determine differences in kinematic walking parameters of older adults between adaptive-speed treadmill (AST), fixed-speed treadmill (FST) and outdoor walking. We hypothesized that self-selected walking speed (SSWS) during AST walking and outdoor walking would increase compared to FST walking. Furthermore, we hypothesized that AST walking and outdoor walking would increase peak knee flexion, hip flexion, and ankle plantarflexion angles compared to FST walking independent of walking speed changes. Methods Fourteen older adult participants were asked to complete 3 min of FST and AST walking on a split-belt treadmill. Participants were also asked to complete 6 min of outdoor walking following a circular route in a neighboring park. A wireless inertial measurement unit-based motion capture system was used to record lower extremity kinematics during all walking conditions. Results The outdoor walking condition produces significantly higher SSWS compared to FST (p < 0.001) and AST (p = 0.02) conditions. A significantly faster SSWS was exhibited during the AST condition compared to the FST condition (p = 0.026). Significantly higher peak ankle plantarflexion angles are exhibited during the outdoor walking condition compared to the AST (p < 0.001, g = 1.14) and FST (p < 0.001, g = 1.13) conditions after accounting for walking speed. There was a significantly lowered difference between the outdoor walking condition and both AST (p = 0.029, g = 0.49) and FST (p = 0.013, g = 0.63) conditions in peak knee flexion angles after accounting for SSWS. There are no significant differences between outdoor, AST, and FST conditions on peak hip flexion angles. Older adults exhibit changes in peak ankle plantarflexion and peak knee flexion angles during outdoor walking compared to treadmill walking but not between treadmill controller types. We found no differences in the kinematics exhibited by older adults between both AST and FST walking. Conclusions Incorporating unconstrained walking speed with the AST while maintaining similar FST sagittal plane kinematics may allow for more translatable conditional balance and walking rehabilitation.

Modulation of Lower Limb Withdrawal Reflexes During Gait: A Topographical Study

2004 ◽  
Vol 91 (1) ◽  
pp. 258-266 ◽  
Author(s):  
Erika G. Spaich ◽  
Lars Arendt-Nielsen ◽  
Ole K. Andersen
Keyword(s):  
Electrical Stimulation ◽  
Gait Cycle ◽  
Sagittal Plane ◽  
Swing Phase ◽  
Hip Joints ◽  
Withdrawal Reflex ◽  
Heel Contact ◽  
Withdrawal Reflexes ◽  
A Site ◽  
Site Dependency

The aim of this study was to investigate the modulation and topography of the nociceptive withdrawal reflex elicited by painful electrical stimulation of the foot sole during gait. Fifteen healthy volunteers participated in this study. Cutaneous electrical stimulation was delivered on five locations of the foot sole after heel-contact, during foot-flat, after heel-off, and during the mid-swing phase of the gait cycle during treadmill walking. Reflexes were recorded from muscles of the ipsilateral and contralateral legs. Furthermore, the kinematic responses in the sagittal plane of the ipsilateral ankle, knee, and hip joints were recorded. Reflexes in the distal muscles showed a site-dependant modulation. The largest responses in tibialis anterior were evoked at the arch of the foot and the smallest at the heel ( P < 0.05). The largest soleus responses were also elicited at the arch of the foot ( P < 0.04). The EMG responses in flexors and extensors of the knee and extensors of the contralateral leg were generally not dependent on the stimulation site. The response at the three joints showed site dependency, especially during the swing phase where maximal flexion was obtained by stimulation at the arch of the foot ( P < 0.05). The withdrawal reflex was modulated during the gait cycle and presented distinctive characteristics for the different muscles studied. Minimal kinematic responses were observed during stance in contrast to swing phase. Modulation of the reflex probably ensures an appropriate withdrawal but primarily secures balance and continuity of movement.

scholarly journals Single-Leg Landings Following a Volleyball Spike May Increase the Risk of Anterior Cruciate Ligament Injury More Than Landing on Both-Legs

2020 ◽  
Vol 11 (1) ◽  
pp. 130
Author(s):  
Datao Xu ◽  
Xinyan Jiang ◽  
Xuanzhen Cen ◽  
Julien S. Baker ◽  
Yaodong Gu
Keyword(s):  
Anterior Cruciate Ligament ◽  
Knee Flexion ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Flexion Angle ◽  
Ligament Injury ◽  
Time Range ◽  
Acl Injuries ◽  
Volleyball Players ◽  
Anterior Cruciate

Volleyball players often land on a single leg following a spike shot due to a shift in the center of gravity and loss of balance. Landing on a single leg following a spike may increase the probability of non-contact anterior cruciate ligament (ACL) injuries. The purpose of this study was to compare and analyze the kinematics and kinetics differences during the landing phase of volleyball players using a single leg (SL) and double-leg landing (DL) following a spike shot. The data for vertical ground reaction forces (VGRF) and sagittal plane were collected. SPM analysis revealed that SL depicted a smaller knee flexion angle (about 13.8°) and hip flexion angle (about 10.8°) during the whole landing phase, a greater knee and hip power during the 16.83–20.45% (p = 0.006) and 13.01–16.26% (p = 0.008) landing phase, a greater ankle plantarflexion angle and moment during the 0–41.07% (p < 0.001) and 2.76–79.45% (p < 0.001) landing phase, a greater VGRF during the 5.87–8.25% (p = 0.029), 19.75–24.14% (p = 0.003) landing phase when compared to DL. Most of these differences fall within the time range of ACL injury (30–50 milliseconds after landing). To reduce non-contact ACL injuries, a landing strategy of consciously increasing the hip and knee flexion, and plantarflexion of the ankle should be considered by volleyball players.

scholarly journals Test Re-test Reliability of Single and Multijoint Strength Properties in Female Australian Footballers

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Daniel Kadlec ◽  
Matthew J. Jordan ◽  
Leanne Snyder ◽  
Jacqueline Alderson ◽  
Sophia Nimphius
Keyword(s):  
Knee Flexion ◽  
Intraclass Correlation ◽  
Strength Properties ◽  
Peak Force ◽  
Test Reliability ◽  
Leg Extension ◽  
Hip Abduction ◽  
Hip Flexion ◽  
Voluntary Contractions ◽  
Trunk Position

Abstract Purpose To examine the test re-test reliability of isometric maximal voluntary contractions (MVC) of hip adduction (ADDISO), hip abduction (ABDISO), and multijoint leg extension (SQUATISO) in sub-elite female Australian footballers. Methods Data were collected from 24 sub-elite female Australian footballers (age 22.6 ± 4.5 years; height 169.4 ± 5.5 cm; body mass 66.6 ± 8.0 kg; 4.5 ± 4.4 years sport-specific training; 2.5 ± 2.0 years unstructured resistance training) from the same club on two non-consecutive days. Participants performed three isometric MVCs of ADDISO, ABDISO, and SQUATISO. The SQUATISO was performed at 140° knee flexion with a vertical trunk position and ADDISO and ABDISO measures were performed in a supine position at 60° of knee flexion and 60° hip flexion. Reliability was assessed using paired t tests and the intraclass correlation coefficient (ICC) with 95% confidence intervals (CI), typical error (TE), and coefficient of variation (CV%) with 95% CI. Results SQUATISO peak force (ICC .95; CV% 4.1), ABDISO for left, right, and sum (ICC .90–.92; CV% 5.0–5.7), and ADDISO for left, right, and sum (ICC .86–.91; CV% 6.2–6.9) were deemed acceptably reliable based on predetermined criteria (ICC ≥ .8 and CV% ≤ 10). Conclusion SQUATISO, ABDISO, and ADDISO tests demonstrated acceptable reliability for the assessment of peak force in sub-elite female Australian footballers, suggesting these assessments are suitable for muscle strength testing and monitoring adaptations to training.

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