P36: Relation between navicular mobility and multi-segment foot kinematics during walking

Carrying asymmetric loads during stair negotiation

O71: Skeletal and anthropometric determinants of gait balance in asymptomatic adult subjects

Carrying asymmetric loads during stair negotiation: Loaded limb stance vs. unloaded limb stance

Mediolateral postural stability when carrying asymmetric loads during stair negotiation

Cutoff values of knee extensor strength for stair ascent and descent after bicruciate-stabilized total knee arthroplasty.

Given the higher fall risk and the fatal sequelae of falls on stairs, it is worthwhile to investigate the mechanism of dynamic balance control in individuals with knee osteoarthritis during stair negotiation. Whole-body angular momentum () is widely used as a surrogate to reflect dynamic balance and failure to constrain may increase the fall risk. This study aimed to compare the range of between people with and without knee osteoarthritis during stair ascent and descent. Seven participants with symptomatic knee osteoarthritis and eight asymptomatic controls were instructed to ascend and descend an instrumented staircase at a fixed cadence. Kinematic and kinetic data were collected and range of in sagittal, frontal, and transverse planes were computed. The knee osteoarthritis group exhibited greater in the sagittal plane during both stair ascent (P = 0.005, Cohen’s d = 1.7) and descent (P = 0.020, Cohen’s d = 1.3) as well as in the transverse plane during stair descent (P = 0.015, Cohen’s d = 1.3), than the control group. These observations may be explained by greater hip flexion (P < 0.05, Cohen’s d > 1.12) and reduced knee flexion moment (P < 0.001, Cohen’s d<-2.77) during stair ascent and descent, and decreased foot progression angle (P = 0.038, Cohen’s d=-1.2) during stair descent, in individuals with knee osteoarthritis. No significant difference in frontal plane was found between the two groups (P > 0.05). Individuals with knee osteoarthritis exhibited greater whole-body angular momentum during stair negotiation when compared to asymptomatic controls. Our findings may provide mechanistic rationale for a greater fall risk among people with knee osteoarthritis.

Can a single lower trunk body-fixed sensor differentiate between level-walking and stair descent and ascent in older adults? Preliminary findings

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

INTRODUCTION: Combat forces perform a number of tasks with a rigid load added to the trunk including walking, running and stair ascent and descent. Though a number of studies have investigated the effect of added loads on joint biomechanics during over ground and treadmill walking, less focus has been applied to negotiating stairs. Changes in lower extremity biomechanics during stair descent may be associated with excessive joint loading. PURPOSE: to quantify changes in joint kinetics when descending stairs with increasing loads. METHODS: Ten healthy adults (age: 18 - 30) performed 5 stair descent trials in each of 5 loading conditions: body weight (BW), BW+5%, BW+10%, BW+15%, and BW+20%. Mass was added using a modular vest and metal plates. An 18-camera motion capture system (240 Hz) and embedded force platform (1200 Hz) was used to collect kinematics and ground reaction forces simultaneously. Commercial biomechanical software was used to calculate ankle, knee and hip joint moments during the stance phase of second step of a five-step stairway. Univariate ANOVAs with Tukey’s post-hoc tests were used to compare peak ankle, knee and hip joint moments from each loaded condition. RESULTS: Ankle plantarflexion moments increased at BW+15% and BW+20% (Table 1). Hip and knee extension moments were not altered with added load. DISCUSSIONS/CONCLUSION: The ankle joint is the primary contributor to increased lower extremity joint moments only in response to added load at or exceeding +15% BW during stair descent. Interestingly, no changes in peak joint moments were observed at the knee and hip joint, suggesting that neither joint is responsible for increased energy absorption in response to added load during stair descent. Further research may seek to investigate the effects of fatigue on joint kinetics during stair descent.

Medial knee loading during stair negotiation in individuals with medial knee osteoarthritis, has only been reported in terms of joint moments, which may underestimate the knee loading. This study assessed knee contact forces (KCF) and contact pressures during different stair negotiation strategies. Motion analysis was performed in five individuals with medial knee osteoarthritis (52.8±11.0 years) and eight healthy subjects (51.0±13.4 years) while ascending and descending a staircase. KCF and contact pressures were calculated using a multi-body knee model while performing step-over-step at controlled and self-selected speed, and step-by-step strategies. At controlled speed, individuals with osteoarthritis showed decreased peak KCF during stair ascent but not during stair descent. Osteoarthritis patients showed higher trunk rotations in frontal and sagittal planes than controls. At lower self-selected speed, patients also presented reduced medial KCF during stair descent. While performing step-by-step, medial contact pressures decreased in osteoarthritis patients during stair descent. Osteoarthritis patients reduced their speed and increased trunk flexion and lean angles to reduce KCF during stair ascent. These trunk changes were less safe during stair descent where a reduced speed was more effective. Individuals should be recommended to use step-over-step during stair ascent and step-by-step during stair descent to reduce medial KCF.

Increased knee loading in stair ambulation in patients dissatisfied with their total knee replacement

Knee adduction moments are not increased in obese knee osteoarthritis patients during stair negotiation

Relationship between stair ambulation with and without a handrail and centre of pressure velocities during stair ascent and descent

Stair negotiation is a daily functional activity that poses greater mechanical burden as compared with level walking. Few studies have investigated the biomechanical demands of stair walking tasks. However, sex-based biomechanical differences of such tasks, in terms of joint movement and muscle activity, have not been previously reported. The aim of this study was to investigate sex-based differences in lower extremity joint kinematics and muscular electromyography (EMG) in healthy adults during stair ascent and descent. A total of 20 participants (10 males and 10 females), with mean±SD age of 21.7±2.7 years, ascended and descended a two-sided staircase. Sagittal movements of the hip, knee, and ankle joints were measured using a Qualisys motion analysis system. Peak amplitude of surface EMG activity for gluteus medius, rectus femoris (RF), vastus lateralis, and soleus muscles was collected using a Biopack EMG system. Each participant performed three repetitions, and an average was calculated for analysis. Female participants demonstrated significantly higher hip and knee angles (P=0.01) during stair ascent and higher hip angles and ankle dorsiflexion (P=0.01) during stair descent than male participants. Female participants also exerted higher normalized muscular activity than male participants for RF, vastus lateralis, and soleus muscles during ascent. However, only RF muscle had significantly higher readings for female participants during stair descent. Female participants perform stair negotiation using greater angular excursion and muscle activation than male participants. This could impose greater mechanical burden on lower extremity structures and, consequently, increase energy consumption. Therefore, sex-based differences should be considered when planning a stair-negotiation rehabilitation program.

Gait analysis post anterior cruciate ligament reconstruction: Knee osteoarthritis perspective