Ankle laxity affects ankle kinematics during a side-cutting task in male collegiate soccer athletes without perceived ankle instability

ObjectivesTo investigate whether ankle joint laxity alone influences lower limb kinematics during a side-cutting task.DesignA cross-sectional study.SettingSports medicine research laboratory.ParticipantsIn total, 66 male collegiate soccer players with history of ankle sprains with no perceived ankle instability were categorised into three groups: no-laxity copers (n = 26), laxity copers (n = 23), and severe-laxity copers (n = 17).Main outcome measuresThe hip, knee, ankle, rearfoot, midfoot, and forefoot kinematic data during the stance phase (0%–100% indicated initial contact to take-off) of a 45° side-cutting task were analysed using one-dimensional statistical parametric mapping.ResultsThe horizontal plane kinematics of the rearfoot differed significantly among the three groups during 30%–91% of the stance phase (P < .05). Severe-laxity copers exhibited a greater external rotation angle than no-laxity copers during 6%–14% and 32%–92% of the stance phase (P < .05).ConclusionOur data suggest that severe ankle joint laxity affects rearfoot horizontal plane kinematics in individuals without perceived ankle instability performing a 45° side-cutting task. These findings could be used by clinicians in developing rehabilitation programs to prevent further ankle sprains in patients with severe ankle joint laxity.     

Assessment of the effect of a total contact cast on lower limb kinematics and joint loading

BackgroundTotal contact casts (TCCs) are used to immobilize and unload the foot and ankle for the rehabilitation of ankle fractures and for the management of diabetic foot complications. The kinematic restrictions imposed by TCCs to the foot and ankle also change knee and hip kinematics, however, these changes have not been quantified before. High joint loading is associated with discomfort and increased risk for injuries. To assess joint loading, the effect of the muscle forces acting on each joint must also be considered. This challenge can be overcome with the help of musculoskeletal modelling.Research questionHow does a TCC affect lower extremity joint loading?MethodsTwelve healthy participants performed gait trials with and without a TCC. Kinematic and kinetic recordings served as input to subject-specific musculoskeletal models that enabled the computation of joint angles and loading. Cast-leg interaction was modelled by means of reaction forces between a rigid, zero-mass cast segment and the segments of the lower extremity.Resultsand Significance: Reduced ankle, knee and hip range of motion was observed for the TCC condition. Statistical parametric mapping indicated decreased hip abduction and flexion moments during initial contact with the TCC. The anterior knee force was significantly decreased during the mid and terminal stance and the second peak of the compressive knee force was significantly reduced for the TCC. As expected, the TCC resulted in significantly reduced ankle loading.SignificanceThis study is the first to quantify the effect of a TCC on lower limb joint loading. Its results demonstrate the efficiency of a TCC in unloading the ankle joint complex without increasing the peak loads on knee and hip. Future studies should investigate whether the observed knee and hip kinematic and kinetic differences could lead to discomfort.     

Lower limb joint-specific contributions to standing postural sway in persons with unilateral lower limb loss

BackgroundIndividuals with lower limb loss are at an increased risk for falls, likely due to impaired balance control. Standing balance is typically explained by double- or single-inverted pendulum models of the hip and/or ankle, neglecting the knee joint. However, recent work suggests knee joint motion contributes toward stabilizing center-of-mass kinematics during standing balance.Research QuestionTo what extent do hip, knee, and ankle joint motions contribute to postural sway in standing among individuals with lower limb loss?MethodsForty-two individuals (25 m/17f) with unilateral lower limb loss (30 transtibial, 12 transfemoral) stood quietly with eyes open and eyes closed, for 30 s each, while wearing accelerometers on the pelvis, thigh, shank, and foot. Triaxial inertial measurement units were transformed to inertial anterior-posterior components and sway parameters were computed: ellipse area, root-mean-square, and jerk. A state-space model with a Kalman filter calculated hip, knee, and ankle joint flexion-extension angles and ranges of motion. Multiple linear regression predicted postural sway parameters from intact limb joint ranges of motion, with BMI as a covariate (p < 0.05).ResultsWith eyes open, intact limb hip flexion predicted larger sway ellipse area, whereas hip flexion and knee extension predicted larger sway root-mean-square, and hip flexion, knee extension, and ankle plantarflexion predicted larger sway jerk. With eyes closed, intact limb hip flexion remained the predictor of sway ellipse area; no other joint motions influenced sway parameters in this condition.SignificanceHip, knee, and ankle motions influence postural sway during standing balance among individuals with lower limb loss. Specifically, increasing intact-side hip flexion, knee extension, and ankle plantarflexion motion increased postural sway. With vision removed, a re-weighting of lower limb joint sensory mechanisms may control postural sway, such that increasing sway may be regulated by proximal coordination strategies and vestibular responses, with implications for fall risk.     

Trunk flexion during walking in people with knee osteoarthritis

BackgroundOver 50% of the body’s mass is concentrated within the head, arms and trunk. Thus, small deviations in the orientation of the trunk, during normal walking, could influence the position of the centre of mass relative to the lower limb joint centres and impact on lower limb biomechanics. However, there are minimal data available on sagittal kinematics of the trunk in people with knee osteoarthritis (OA) during walking.Research questionDo people with knee OA have altered kinematic patterns of the trunk, pelvis or hip compared with healthy control participants during walking?MethodsStatistical parametric mapping was used to compare sagittal and frontal plane kinematic patterns, during walking, between a healthy group and cohort of people with knee OA.ResultsIndividuals with knee OA walked with a mean increase in trunk flexion of 2.6°. Although this difference was more pronounced during early stance, it was maintained across the whole of stance phase. There were no differences, between the groups, in sagittal plane pelvic or hip kinematics. There were also no differences in trunk, pelvic or hip kinematics in the frontal plane.SignificanceMost previous gait research investigating trunk motion in people with knee OA has focused on the frontal plane. However, our data suggest that an increase in sagittal trunk flexion may be a clinical hallmark of people with this disease. Altered trunk flexion could affect joint moments and muscle patterns and therefore our results motivate further research in this area.     

Lower limb kinematics during single leg landing in three directions in individuals with chronic ankle instability

ObjectivesTo compare the lower limb kinematics of participants with chronic ankle instability (CAI) and healthy participants during forward, lateral, and medial landings.DesignCross-sectional study.SettingLaboratory.ParticipantsEighteen athletes with CAI and 18 control athletes.Main outcome measuresHip, knee, and ankle joint kinematics during forward, lateral, and medial single-leg landings were compared between the groups using two-way ANOVA for discrete values and statistical parametric mapping two-sample t-tests for time-series data.ResultsThe CAI group had significantly greater ankle dorsiflexion than the control group (P ≤ 0.013), which was observed from the pre-initial contact (IC) for lateral and medial landings and post-IC for forward landing. The CAI group showed greater knee flexion than the control group from the IC for lateral landing and post-IC for forward landing (P ≤ 0.014). No significant differences in ankle inversion kinematics were found between the CAI and control groups. Lateral landing had a greater peak inversion angle and velocity than forward and medial landings (P < 0.001). Medial landing had a greater inversion velocity than forward landing (P < 0.001).ConclusionsThis study suggests that individuals with CAI show feedforward protective adaptations in the pre-landing phase for lateral and medial landings.     

Hip external rotation stiffness and midfoot passive mechanical resistance are associated with lower limb movement in the frontal and transverse planes during gait

BackgroundHip external rotation stiffness, midfoot passive mechanical resistance and foot alignment may influence on ankle, knee and hip movement in the frontal and transverse planes during gait.Research questionAre hip stiffness, midfoot mechanical resistance and foot alignment associated with ankle, knee and hip kinematics during gait?MethodsHip stiffness, midfoot mechanical resistance, and foot alignment of thirty healthy participants (18 females and 12 males) with average age of 25.4 years were measured. In addition, lower limb kinematic data during the stance phase of gait were collected with the Qualisys System (Oqus 7+). Stepwise multiple linear regressions were performed to identify if hip stiffness, midfoot torque, midfoot stiffness and foot alignment were associated with hip and knee movement in the transverse plane and ankle movement in the frontal plane with α = 0.05.ResultsReduced midfoot torque was associated with higher hip range of motion (ROM) in the transverse plane (r² = 0.18), reduced hip stiffness was associated with higher peak hip internal rotation (r² = 0.16) and higher ROM in the frontal plane (r² = 0.14), reduced midfoot stiffness was associated with higher peak knee internal rotation (r² = 0.14) and increased midfoot torque and midfoot stiffness were associated with higher peak knee external rotation (r² = 0.36).SignificanceThese findings demonstrated that individuals with reduced hip and midfoot stiffness have higher hip and knee internal rotation and higher ankle eversion during the stance phase of gait. On the other hand, individuals with increased midfoot torque and stiffness have higher knee external rotation. These relationships can be explained by the coupling between ankle movements in the frontal plane and knee and hip movements in the transverse plane. Finally, this study suggests that midfoot passive mechanical resistance and hip stiffness should be assessed in individuals presenting altered ankle, knee and hip movement during gait.     

Threshold of equinus which alters biomechanical gait parameters in children

The main aim of this study was to define the threshold angle of equinus beyond which significant changes in 3D lower limb kinematics and kinetics occur in typically developing children and to describe these changes.A customized orthosis was fitted on the right ankle of 10 typically developing children and was adjusted to +10° ankle dorsiflexion, 0°, ?10°, ?20° plantarflexion and maximum plantarflexion. Gait was analyzed using an optoelectronic system. A gait velocity of 1 m/s was imposed.Most of the kinematic and kinetic changes were significantly altered from the ?10° condition. In the sagittal plane, the results showed increased knee flexion at initial contact, increased knee flexion or hyperextension in stance, increased hip flexion at initial contact and increased anterior pelvic tilt. Other changes included increased knee varus, reduced hip adduction and more internal foot progression. The ankle plantarflexion moment was bi-phasic during stance, peak ankle power generation was reduced, peak knee extension moment was decreased and hip extension moments increased. On the contralateral side, there was a significant increase in ankle plantarflexion at initial contact and a significant decrease in knee flexion during swing phaseat maximum plantarflexion.Although slight modifications occurred for smaller degrees of equinus, the results suggest that significant kinematic and kinetic changes occurred during gait in both limbs from 10° of plantarflexion. The results of this study also provide some indications regarding the primary causes of gait deviations and secondary compensatory strategiesin children with a clinical dorsiflexion limitation.     

Effect of gender on lower extremity kinematics during rapid direction changes: An integrated analysis of three sports movements

Anterior cruciate ligament (ACL) injury is a common sports injury, particularly in females. Gender differences in knee kinematics have been observed for specific movements, but there is limited information on how these findings relate to other joints and other movements. Here we present an integrated analysis of hip, knee and ankle kinematics across three movements linked to non-contact ACL injury. It was hypothesised that there are gender differences in lower extremity kinematics, which are consistent across sports movements. Ten female and ten male NCAA basketball players had three-dimensional hip, knee and ankle kinematics quantified during the stance phase of sidestep, sidejump and shuttle-run tasks. For each joint angle, initial value at contact, peak value and between-trial variability was obtained and submitted to a two-way mixed design ANOVA (gender and movement), with movement condition treated as a repeated measure. Females had higher peak knee valgus and lower peak hip and knee flexion, with the same gender differences also existing at the beginning of stance (p<0.05). Peak valgus measures were highly correlated between movements, but not to static valgus alignment. Kinematic differences demonstrated by females for the sports movements studied, and in particular knee valgus, may explain their increased risk of ACL injury. These differences appear to stem largely from subject-specific neuromuscular mechanisms across movements, suggesting that prevention via neuromuscular training is possible.     

Sagittal plane kinematic differences between dominant and non-dominant legs in unilateral and bilateral jump landings

ContextIn both research and clinical settings there is an assumption of symmetry between limbs in landing. However, development of a preferred limb side is a natural occurrence. It is not well established how limb dominance affects landing mechanics in a unilateral or bilateral landing.ObjectiveTo investigate sagittal plane mechanics between dominant and non-dominant legs in both unilateral and a bilateral landing tasks.DesignCross-sectional study.SettingLaboratory environment.Participants148 male athletes.Main outcome measuresSagittal plane kinematics (hip, knee, and ankle flexion) at initial contact and maximum knee flexion, and total excursion of the movement.ResultsNo significant differences were found between limbs in the unilateral landing. Knee flexion (p = 0.02) and hip flexion (p = 0.00) were significantly different between dominant and non-dominant limbs at initial contact in the bilateral landing. Knee flexion total excursion (p = 0.04) and hip flexion total excursion (p = 0.03) in the bilateral landing were also significantly different between limbs.ConclusionsLower limb symmetry was observed for the unilateral landing. Minimal, yet significant, asymmetries (less than 2°) were present during the bilateral landing. This finding justifies the continued use of the dominant limb in research and clinical settings.     

Effect of altered sagittal-plane knee kinematics on loading during the early stance phase of gait

BackgroundIndividuals with knee osteoarthritis (OA) show various dynamic sagittal-plane changes during the early stance phase of gait. However, the effect of these kinematic alterations on knee load during the early stance remains poorly understood. Research question: The purpose of this study was to examine the effect of altered sagittal- plane knee kinematics on knee load during the early stance.MethodsA total of 13 healthy adult men underwent gait analysis trials using four conditions (baseline and three altered conditions). The three altered conditions were defined as follows:1) Less flexion (LF): a gait that decreased knee flexion excursion (KFE) owing to a reduced peak knee flexion angle compared to baseline.2) Initial flexion (IF): a gait with decreased KFE owing to an increased knee flexion angle at initial contact, during which the peak knee flexion angle did not differ from baseline.3) Flexion gait (FG): a gait that increased the knee flexion angle at initial contact but did not reduce KFE compared with the baseline.Data analyzed included peak external knee flexion moment (KFM), KFM impulse (impulse was an integral value from initial contact to peak value), peak vertical ground reaction force (VGRF), and maximum loading rate.ResultsBoth LF and IF conditions significantly decreased peak VGRF (p < 0.05) compared with the baseline. Peak KFM decreased in the LF condition and increased in the FG condition versus baseline (p < 0.05). A significantly increased KFM impulse was found in both IF and FG conditions when compared with baseline (p < 0.05).SignificanceAn increase in knee flexion angle during early stance increased knee loading. Interventions are likely required for improving excessive knee flexion during early stance phase of gait in individuals with knee OA.     

Fatigue matters: An intense 10 km run alters frontal and transverse plane joint kinematics in competitive and recreational adult runners

BackgroundFatigue is an essential component of distance running. Still, little is known about the effects of running induced fatigue on three-dimensional lower extremity joint movement, in particular in the frontal and transverse planes of motion.Research questionHow are non-sagittal plane lower extremity joint kinematics of runners altered during a 10 km treadmill run with near-maximum effort?MethodsIn a cross-sectional study design, we captured three-dimensional kinematics and kinetics at regular intervals throughout a 10 km treadmill run in 24 male participants (subdivided into a competitive and recreational runner group) at a speed corresponding to 105 % of their season-best time. We calculated average and peak joint angles at the hip, knee and ankle during the stance phase.ResultsWe observed peak deviations of 3.5°, 3° and 5° for the hip (more adduction), knee (more abduction) and ankle (more eversion) in the frontal plane when comparing the final (10 km) with the first (0 km) measurement. At the end of the run peak knee internal rotation angles increased significantly (up to 3° difference). Running with a more abducted knee joint and with a higher demand for hip abductor muscles in the unfatigued state was related to greater fatigue-induced changes of joint kinematics at the knee and hip.SignificanceThe fatigue related change of non-sagittal joint kinematics needs to be considered when addressing risk factors for running-related injuries, when designing shoe interventions as well as strengthening and gait retraining protocols for runners. We speculate that strengthening ankle invertors and hip abductors and monitoring the dynamic leg axis during running appear to be promising in preventing fatigue induced alterations of non-sagittal joint kinematics.     

The effect of the most common gait perturbations on the compensatory limb’s ankle,knee, and hip moments during the first stepping response

BackgroundTrips and slips, the two most common gait perturbations, often cause falls. Multiple studies have focused mainly on the kinematics of multiple body segments in response to an unexpected trip or slip induced by mechanical obstacles, cables, treadmills, and slippery agents or contaminants on a floor. Few studies have examined the joint moments of the compensatory limb following an unexpected trip on an obstacle.Research questionThis proof-of-concept study sought to assess the ankle, knee, and hip moments of the compensatory limb during normal walking and the first stepping response following the two most common gait perturbations.MethodsEighteen healthy young adults completed 4 trials (2 trials with a random trip perturbation and 2 trials with a random slip perturbation) while walking on a split-belt treadmill. In each trial, the motorized treadmill induced either an unexpected trip or slip perturbation to the left foot between the 31 st and 40th step randomly. A motion capture system recorded the positions of body segments, the joint moments (i.e., ankle, knee, and hip moments) of the compensatory limb were quantified, and the maximum joint moments were assessed during normal walking and the first stepping response.ResultsCompensatory limb’s ankle plantarflexion, knee flexion, hip flexion, and hip extension moments were significantly higher for a slip perturbation than for a trip perturbation during the first stepping response. Compensatory limb’s knee flexion, hip flexion, and hip extension moments were also significantly higher during the first stepping response to a slip perturbation compared to normal walking.SignificanceThis proof-of-concept study is the first to investigate the ankle, knee, and hip moments of the compensatory limb during the first stepping response following unexpected gait perturbations induced by a split-belt treadmill. The findings are expected to improve the gait perturbation paradigms developed for training balance-impaired individuals.     

Altered movement strategies during jump landing/cutting in patients with chronic ankle instability

Centrally mediated changes in sensorimotor function have been reported in patients with chronic ankle instability (CAI). However, little is known regarding supraspinal/spinal adaptations during lower‐extremity dynamic movement during a multiplanar, single‐leg landing/cutting task. The purpose of this study was to investigate the effect of CAI on landing/cutting neuromechanics, including lower‐extremity kinematic, electromyography (EMG) activation, and ground reaction force (GRF) characteristics. One hundred CAI patients and 100 matched healthy controls performed five trials of a jump landing/cutting task. Sagittal‐ and frontal‐plane ankle, knee and hip kinematics, EMG activation in eight lower‐extremity muscles, and 3D GRF were collected during jump landing/cutting. Functional analyses of variance (FANOVA) were used to evaluate between‐group differences for dependent variables throughout the entire ground contact of the task. Relative to the control group, the CAI group revealed (a) reduced dorsiflexion, increased knee and hip flexion angles, (b) increased inversion and hip adduction angles, (c) increased EMG activation of medial gastrocnemius, peroneus longus, adductor longus, vastus lateralis, gluteus medius, and gluteus maximus, and (d) increased posterior and vertical GRF during initial landing, and reduced medial, posterior, and vertical GRF during mid‐landing and mid‐cutting. CAI patients demonstrated alterations in landing/cutting movement strategies as demonstrated by a higher susceptibility of foot placement for lateral ankle sprains, and more flexed positions of the knee and hip with higher EMG activation of knee and hip extensors to modulate GRF to compensate for the unstable ankle. This apparent compensation may be due to mechanical (limited dorsiflexion angle) and/or sensorimotor deficits in the ankle.     

Kinematic changes in patients with severe knee osteoarthritis are a result of reduced walking speed rather than disease severity

BackgroundKinematic changes in patients with knee osteoarthritis (OA) have been extensively studied. Concerns have been raised whether the measured spatiotemporal and kinematic alterations are associated with disease progression or merely a result of reduced walking speed.Research question: The purpose of this study was to investigate the effect of walking speed on kinematic parameters in patients with knee OA using statistical parametric mapping (SPM).MethodsTwenty-three patients with unilateral knee OA scheduled for a total knee replacement and 28 age matched control subjects were included in this study. Spatiotemporal parameters and sagittal plane kinematics were measured in the hip, knee, and ankle using the inertial sensors system RehaGait® while walking at a self-selected normal (patients and controls) and slow walking speed (controls) for a distance of 20 m. Gait parameters were compared between groups for self-selected walking speed and for matched walking speed using SPM with independent sample t tests.ResultsAt self-selected walking speed, patients had significantly lower knee flexion during stance (maximum difference, -6.8°) and during swing (-11.0°), as well as higher ankle dorsiflexion during stance phase (+12.5°) and lower peak hip extension at the end of stance compared to controls (+4.2°). At matched speed, there were no significant differences in joint kinematics between groups.SignificanceDifferences in sagittal plane gait kinematics between patients with knee OA and asymptomatic controls appear to be mainly a result of reduced walking speed. These results emphasize the importance of considering walking speed in research on gait kinematics in patients with knee OA and in clinical trials using gait parameters as outcome measures.     

Effects of artificially induced bilateral internal rotation gait on gait kinematics and kinetics

BackgroundBilateral internal rotation gait is a common gait abnormality in children with bilateral cerebral palsy, but still not fully understood.Research questionThe aim of this clinical study was to analyze the effects of artificially induced bilateral internal rotation gait on kinematics and kinetics. Our hypothesis was, that the internal rotation gait defined as increased dynamic internal hip rotation itself causes significant alterations in gait kinematics and kinetics.Methods30 typically developing children with a mean age of 12 (SD 3) years (range 8 – 16) performed three-dimensional gait analysis in two different conditions: with unaffected gait and with artificially induced bilateral internal rotation gait with two rotation bandages worn in order to internally rotate the hips. Kinematic and kinetic changes between these two conditions were calculated and compared using a mixed linear model with “gait condition” as fixed effect and both “limb” and “patient” as random effects.ResultsThe rotation bandages induced a significant increase in internal hip rotation and foot progression angle towards internal without affecting pelvic rotation. The peak hip internal rotator moment during loading response and the peak hip external rotator moment during the first half of stance phase increased significantly and the peak hip internal rotator moment during the second half of stance phase decreased significantly. Anterior pelvic tilt, hip flexion, knee flexion and ankle dorsiflexion increased significantly. The first peak of the frontal hip moment decreased, and the second increased significantly. The second peak of the frontal knee moment decreased significantly, while the first didn’t change significantly.SignificanceThe data suggest, that the bilaterally increased dynamic internal hip rotation itself has a relevant impact on frontal hip moments. The increased anterior pelvic tilt, hip and knee flexion may be either induced by the pull of the rotation bandage or a secondary gait deviation.     

Females with patellofemoral pain have impaired impact absorption during a single-legged drop vertical jump

BackgroundFemales with patellofemoral pain (PFP) have been reported to land with altered biomechanics in some, but not all studies. Kinematic alterations previously reported may indicate, and relate to potential impairments in absorbing impact.Research questionTo compare vertical ground reaction force (vGRF) and lower limb kinematics during single-legged drop vertical jumps in females with and without PFP; and establish the relationship between vGRF and kinematics during this task.MethodsFifty-two physically active females (26 with PFP and 26 controls) participated in the present cross-sectional study. Peak of vGRF was evaluated during landing; and lower limb kinematics in the sagittal and frontal planes during deceleration (landing) and acceleration (take-off) phases were evaluated.ResultsThe PFP group had 11% greater vGRF (p < 0.01); and 13–24% lower hip, knee and ankle excursion in the sagittal plane during acceleration and deceleration phases (p ≤ 0.02) compared to the control group. No significant between group differences (p > 0.05) for hip, knee and ankle excursion in the frontal plane were identified. Greater impact was significantly correlated with reduced knee (r = –0.56), hip (r = –0.50) and ankle (r = –0.41) excursion in the sagittal plane during the acceleration phase in the control group, but not in the PFP group. No significant correlations were found between vGRF and kinematics variables during the deceleration phase in either group.SignificanceImpaired ability to absorb load and reduced lower limb movement in the sagittal plane during landing in females with PFP may provide separate treatment targets during rehabilitation.     

慢性膝关节前交叉韧带损伤患者步态的运动学分析

目的:探讨慢性膝关节前交叉韧带(ACL)损伤患者下肢关节运动学变化特点。方法:30名慢性ACL损伤患者为损伤组,30名健康人为对照组,利用三维运动分析系统对实验对象进行步态分析,比较两组的时间距离指标;比较两组在预承重期髋、膝关节最大屈曲角度和踝关节最大跖屈角度,以及膝关节最大外旋角度。结果:同对照组比较,损伤组步频、步速显著减小,步态周期时间显著增加(P<0.05)。在预承重期,损伤组最大屈髋角度同对照组相比无明显差异,最大屈膝角度显著小于对照组(P<0.05),最大跖屈角度显著小于对照组(P<0.05),最大胫骨外旋角度显著大于对照组(P<0.05)。结论:慢性ACL损伤患者行走时步态出现膝关节屈曲、踝关节跖屈角度的改变,同时,膝关节旋转角度也发生改变。     

Influence of the exacerbation of patellofemoral pain on trunk kinematics and lower limb mechanics during stair negotiation

BackgroundAlthough it is assumed that the presence of patellofemoral pain (PFP) may result in compensatory behaviors that can alter trunk kinematics and lower limb mechanics, the influence of the exacerbation of patellofemoral pain on trunk kinematics and lower limb mechanics during stair negotiation has not been established.Research questionDoes the exacerbation of PFP symptoms lead to altered trunk kinematics and lower limb mechanics during stair negotiation?MethodsThree-dimensional kinematics and kinetics were obtained from 45 women with PFP during stair descent and ascent. Data were obtained before and after a pain exacerbation protocol. The variables of interest were peak trunk, hip, and knee flexion, and ankle dorsiflexion; peak hip, and knee extensor, and ankle plantarflexor moments. Paired t-tests were used to compare the variables of interest before and after pain exacerbation.ResultsFollowing pain exacerbation, there was a decrease in peak knee extensor moment during stair descent (Effect size = −0.68; p = 0.01) and stair ascent (Effect size = −0.56; p = 0.02); as well as in peak ankle dorsiflexion during stair descent (Effect size = −0.33; p = 0.01) and stair ascent (Effect size = −0.30; p = 0.01). An increase in ankle plantarflexor moment during stair descent (Effect size = 0.79; p < 0.01) and stair ascent (Effect size = 0.89; p < 0.01) was also observed. No significant differences were observed for peak trunk, hip, and knee flexion or hip extensor moment (p > 0.05).SignificanceOur findings show compensatory strategies used by people with PFP in response to symptoms exacerbation that may have a negative impact on knee and ankle mechanics. Our findings also suggest that people with PFP do not seem to change their trunk, hip, and knee flexion or hip extensor moment during stair negotiation in response to symptom exacerbation.     

Mid-flight trunk flexion and extension altered segment and lower extremity joint movements and subsequent landing mechanics

ObjectivesTo assess the effect of mid-flight trunk flexion and extension on the movements of body segments and lower extremity joints and subsequent landing mechanics during a jump-landing task.DesignParticipants performed three jump-landing conditions in a randomized order.MethodsForty-one participants completed jump-landing trials when performing three different mid-flight trunk motion: reaching forward, reaching up, and reaching backward. Whole-body kinematic and ground reaction force data were collected.ResultsThe reaching backward condition resulted in a more posteriorly positioned upper body center of mass (COM) and more anteriorly positioned pelvis COM, legs COM, hip, and knee joint positions relative to the whole-body COM in flight and at initial contact of landing. The reaching backward condition showed the least hip flexion and ankle plantarflexion angles at initial contact as well as the least hip and knee flexion angles and the greatest ankle dorsiflexion angles at 100 ms after landing. The reaching backward condition also demonstrated the greatest peak posterior ground reaction forces, peak and average knee extension moments, peak and average hip flexion moments, and peak knee varus moments within the first 100 ms after landing. Opposite changes were observed for the reaching forward condition.ConclusionsMid-flight trunk extension resulted in body postures that predisposed individuals to land with increased knee extension and varus moments and decreased knee flexion angles, which are indirectly associated with increased ACL loading. These findings may help to understand altered trunk motion during certain ACL injury events and provide information for developing jump-landing training strategies.     

Kinematic adaptation and changes in gait classification in running compared to walking in children with unilateral spastic cerebral palsy

BackgroundClassification of sagittal gait patterns in unilateral spastic cerebral palsy (CP) provides direct implication for treatment. Five types are described: type 0 has minor gait deviation; type 1 has inadequate ankle dorsiflexion in swing; type 2 has inadequate ankle dorsiflexion throughout the gait cycle; types 3 and 4 have abnormal function of the knee and hip joint respectively. During gait analysis of children with unilateral spastic CP we observed frequently that a knee flexion deficit disappeared during running. That may have an impact on classification and treatment.Research questionDoes the classification type change while running and how do patients’ kinematics adapt to running?Methods64 children with unilateral spastic CP were classified using instrumented gait analysis for walking and running. The deviation of four parameters from typically developing children (TD) were used to distinguish between types: peak ankle dorsiflexion in swing for type 1, peak ankle dorsiflexion in stance for type 2, knee range of motion for type 3, and hip range of motion for type 4. A three-factor ANOVA for factors group (CP/TD), locomotion (walk/run) and limb side (in-/uninvolved) was conducted.ResultsThe number of patients with type 1, 3 and 4 decreased considerably from walking to running, whereas, the number of type 0 and 2 patients increased. The ANOVA showed that three of four parameters of patients’ pathologic limb adapt similarly to TD to running, except for the ankle dorsiflexion in stance.SignificanceRunning shows that there is a natural way to resolve abnormalities. Therefore, recommended treatments of hip and knee joint abnormalities based on the walking classification can be questioned and additional running analysis may be important for surgical decision making.