Article

Lateral trunk lean gait modification increases the energy cost of treadmill walking in those with knee osteoarthritis

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Abstract

To compare the energy expenditure of increased lateral trunk lean walking - a suggested method of reducing medial compartment knee joint load - compared to normal walking in a population of older adults with medial knee osteoarthritis (OA). Participants completed two randomly-presented treadmill walking conditions: 15 minutes of normal walking or walking with ten degrees of peak lateral trunk lean. Lateral trunk lean angle was displayed in front of the participant in real-time during treadmill conditions. Energy expenditure (VO2 and METs), heart rate, peak lateral trunk lean angle, knee pain and perceived exertion were measured and differences between conditions were compared using paired t-tests. Twelve participants (5 males, mean (SD) age 64.1(9.4) years, BMI 28.3(4.9) kg/m²) participated. All measures were significantly elevated in the lateral trunk lean condition (p < 0.008), except for knee pain (p = 0.22). Oxygen consumption (VO2) was, on average 9.5% (95% CI 4.2 - 14.7%) higher, and heart rate was on average 5.3 beats per minute (95% CI 1.7 - 9.0 bpm) higher during increased lateral trunk lean walking. Increased lateral trunk lean walking on a treadmill resulted in significantly higher levels of steady-state energy expenditure, heart rate, and perceived exertion, but no difference in knee pain. While increased lateral trunk lean has been shown to reduce biomechanical measures of joint loading relevant to OA progression, it should be prescribed with caution given the potential increase in energy expenditure experienced when it is employed.

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... Many previous studies focused on lateral trunk lean toward the ipsilateral limb (Hunt et al., 2008;Hunt et al., 2011;Simic et al., 2012;Takacs et al., 2014;van der Esch et al., 2011). This proximal adaption is suggested to be a dominant means patients use to avoid severe knee pain and cartilage contact stress in the knee joint. ...
... All rights reserved. Esch et al., 2011), and increased trunk lean did not immediately improve symptoms (Simic et al., 2012;Takacs et al., 2014). Further, the relationship between lateral trunk lean and EKAM is likely weaker in individuals with moderate to severe knee OA than in those with mild knee OA (Hunt et al., 2008). ...
... The weak relationship between lateral trunk motion and knee pain found in previous studies (Hunt et al., 2008;van der Esch et al., 2011) supports our findings. Increased trunk lean did not result in immediate changes in symptoms (Simic et al., 2012;Takacs et al., 2014), although EKAM decreased in a dose-response manner (Simic et al., 2012). This finding exposes a discrepancy between EKAM and knee pain intensity. ...
Article
Clarifying proximal gait adaptations as a strategy to reduce knee joint loading and pain for individuals with knee osteoarthritis (OA) contributes to understanding the pathogenesis of multi-articular OA changes and musculoskeletal pain in other joints. We aimed to determine whether biomechanical alterations in knee OA patients during level walking is increased upper trunk lean in the frontal and sagittal planes, and subsequent alteration in external hip adduction moment (EHAM) and external hip flexion moment (EHFM). A literature search was conducted in PubMed, PEDro, CINAHL, and Cochrane CENTRAL through May 2018. Where possible, data were combined into a meta-analysis; pooled standardized mean differences (SMD) of between knee OA patients and healthy adults were calculated using a random-effect model. In total, 32 articles (2037 participants, mean age, 63.0 years) met inclusion criteria. Individuals with knee OA had significantly increased lateral trunk lean toward the ipsilateral limb (pooled SMD: 1.18; 95% CI: 0.59, 1.77) along with significantly decreased EHAM. These subjects also displayed a non-significantly increased trunk/pelvic flexion angle and EHFM. The GRADE approach judged all measures as “very low.” These results may indicate that biomechanical alterations accompanying knee OA are associated with increased lateral trunk lean and ensuing alterations in EHAM. Biomechanical alterations in the sagittal plane were not evident. Biomechanical adaptations might have negative sequelae, such as secondary hip abductor muscle weakness and low back pain. Thus, investigations of negative sequelae due to proximal gait adaptations are warranted.
... A previous study showed that trunk lean gait increased the energy cost 17) . Human walking is performed by the exchange of gravitational potential and kinetic energies 18) , and it is performed by controlling periodic vertical displacement of wholebody COM during each stride 19) . ...
... With regard to trunk lean gait, the subjects were instructed to lean the trunk toward the study limb during the ipsilateral stance phase and to reach maximum trunk lean to the target angle after initial contact of the study limb. Usual trunk motion was encouraged during the contralateral stance phase 14,15,17) . Using a real-time visual feedback system, subjects were instructed to increase their trunk lean angle to the target angle equal to 10° greater than that observed during normal gait 15,17) . ...
... Usual trunk motion was encouraged during the contralateral stance phase 14,15,17) . Using a real-time visual feedback system, subjects were instructed to increase their trunk lean angle to the target angle equal to 10° greater than that observed during normal gait 15,17) . This target trunk lean angle was then set on the real-time visual feedback projector screen, which was positioned directly in front of the subjects. ...
Article
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[Purpose] The strategy of trunk lean gait to reduce external knee adduction moment (KAM) may affect multi-segmental synergy control of center of mass (COM) displacement. Uncontrolled manifold (UCM) analysis is an evaluation index to understand motor variability. The purpose of this study was to investigate how motor variability is affected by using UCM analysis on adjustment of the trunk lean angle. [Subjects and Methods] Fifteen healthy young adults walked at their preferred speed under two conditions: normal and trunk lean gait. UCM analysis was performed with respect to the COM displacement during the stance phase. The KAM data were analyzed at the points of the first KAM peak during the stance phase. [Results] The KAM during trunk lean gait was smaller than during normal gait. Despite a greater segmental configuration variance with respect to mediolateral COM displacement during trunk lean gait, the synergy index was not significantly different between the two conditions. The synergy index with respect to vertical COM displacement during trunk lean gait was smaller than that during normal gait. [Conclusion] These results suggest that trunk lean gait is effective in reducing KAM; however, it may decrease multi-segmental movement coordination of COM control in the vertical direction.
... It is often accompanied by an increase in hip internal rotation [4,30,36]. Although lateral trunk sway is an effective gait modification that decreases the early stance peak of KAdM, it seems to be uncomfortable and difficult to maintain, increases the energy cost, and may affect balance [29,32,36]. ...
... Wheeler et al. [39] and Shull et al. [29] have both reported that the most commonly used modification that subjects preferred by subjects was toeing-in. Trunk sway as a modification might be uncomfortable, is difficult to maintain, increases the energy cost, or could decrease balance [29,32]. Toe-out gait does not decrease the early stance peak KAdM and may even increase this peak [36] or change the external knee flexion moment [19], thus potentially limiting the effect of decreasing medial contact force in the knee [29,38]. ...
Article
Real-time visual feedback might be effective for gait retraining in patients with knee osteoarthritis, to potentially relieve symptoms and postpone knee replacement. In this study, we investigated the effect of various types of real-time visual feedback on a kinetic and a kinematic gait parameter and the different kinematic strategies adopted to reduce knee load. Seventeen healthy subjects walked on an instrumented treadmill while receiving real-time visual kinetic feedback aimed at minimizing the external knee adduction moment (KAdM, reflecting the knee load) or kinematic feedback on the hip internal rotation angle (HIR, a gait modification to reduce the KAdM). Four types of visual feedback (bar, polar plot, color change, graph) were provided. The KAdM decreased by 50 % with kinetic feedback, while kinematic feedback resulted in an HIR increase of 8° but no decrease in KAdM. The degree of change was not influenced by the type of visual feedback. The kinematic changes that reduced KAdM were increased toe-in, increased step width, and decreased hip adduction. Real-time visual feedback can effectively modify gait parameters. Feedback of the KAdM may be more effective in reducing the KAdM than controlling a kinematic parameter that is assumed to unload the knee.
... If this is not possible, leaning the trunk over the affected hip can be an effective compensation, either by decreasing the moment arm between the ground reaction force and the hip center, which reduces demand on the abductors, or by ensuring swing limb clearance. In several patient populations, it has been shown that increased trunk motion increases the energy cost of walking [19,20], or decreases walking efficiency [21]. Thus, hip abductor impairment may serve to reduce walking efficiency and lead to excessive energy use during walking. ...
... However, we did not directly evaluate the underlying assumption that this hypothesis was based on. We presumed that women with hip OA compensate for abductor weakness with increased frontal plane trunk motion, which studies have shown is energetically costly [19][20][21]. This gait compensation has been demonstrated in women with total hip replacements [18], however it has not been directly shown in hip OA. ...
Article
Background Osteoarthritis (OA) can hinder physical activity in older adults for reasons that are not fully understood. Functional barriers may exist such as reduced muscle strength around the affected joint, potentially affecting physical activity. Aging-associated declines in energy capacity may also be exacerbated by OA. These factors may work together to influence physical activity in people with OA. Research question Our objective was to evaluate the combined role of walking energetics and hip abductor strength on physical activity in older women with hip OA. Methods We evaluated 30 women with moderately symptomatic hip OA (61 ± 10 yrs; 30.7 ± 4.9 kg/m²) in this cross-sectional observational study. We measured physical activity using the UCLA activity score and quantified activity frequency and intensity using accelerometers worn for seven days (7 ± 2 days). We used a portable oxygen exchange system to measure energy used during walking at preferred speeds (relative to total energy capacity assessed using a six-minute walk test) and a dynamometer to measure hip abductor strength. We used Pearson correlations and regression analysis to test our hypotheses. Results Greater energy used during walking was associated with lower self-reported physical activity (R=-0.626, p < 0.001), more sedentary time (R = 0.567, p = 0.002), and less light activity time (R=-0.644, p < 0.001). Lower hip abductor strength was associated with lower self-reported physical activity (R = 0.406, p = 0.039). While there was no association between hip abductor strength and energy used during walking, together these variables predicted 55.5% of the variance in self-reported physical activity. Significance Results suggest intervention targets to promote physical activity in this population.
... Normal, or "optimized," motions of the center of mass (COM), for example, are expected to result in the greatest walking economy [10,11]. Excessive out-of-plane movements, such as side-to-side sway, can adversely affect the metabolic demand of walking [12,13] and are commonly observed in individuals with amputations [14][15][16]. However, research suggests that reducing COM deviations by externally controlling frontal plane movement lowers the energy cost of walking [17]. ...
Article
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The metabolic demand of walking generally increases following lower extremity amputation. This study used real-time visual feedback to modify biomechanical factors linked to an elevated metabolic demand of walking in individuals with transtibial amputation. Eight persons with unilateral, traumatic transtibial amputation and 8 uninjured controls participated. Two separate bouts of real-time visual feedback were provided during a single session of gait retraining to reduce 1) center of mass sway and 2) thigh muscle activation magnitudes and duration. Baseline and post-intervention data were collected. Metabolic rate, heart rate, frontal plane center of mass sway, quadriceps and hamstrings muscle activity, and co-contraction indices were evaluated during steady state walking at a standardized speed. Visual feedback successfully decreased center of mass sway 12% (p = 0.006) and quadriceps activity 12% (p = 0.041); however, thigh muscle co-contraction indices were unchanged. Neither condition significantly affected metabolic rate during walking and heart rate increased with center-of-mass feedback. Metabolic rate, center of mass sway, and integrated quadriceps muscle activity were all not significantly different from controls. Attempts to modify gait to decrease metabolic demand may actually adversely increase the physiological effort of walking in individuals with lower extremity amputation who are young, active and approximate metabolic rates of able-bodied adults.
... However, these altered gait patterns may lend to a greater oxygen cost for physical activity compared with individuals who do not have OA. For instance, Takacs et al. found that one suggested method of relieving knee loading, the lateral trunk lean, resulted in 9.5% greater oxygen consumption and perceived exertion compared to normal walking in older adults with OA [71]. This has also been observed in older adults with diagnosed ankle OA [72]. ...
Article
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Purpose of Review Osteoarthritis (OA) affects a large percentage of older adults. Prevalence of OA in younger adults is growing due to traumatic joint injuries occurring through sport participation. The purpose of this review is to summarize the recent literature linking lower extremity musculoskeletal injuries to post-traumatic osteoarthritis (PTOA), summarize the biomechanical and movement strategy consequences of these injuries, and link these consequences with known metabolic risk factors associated with general OA specifically in the aging population. Recent Findings Approximately 30% of younger adults have radiographic OA within one year after traumatic knee injury. An estimated 50% of individuals with chronic ankle instability will suffer from PTOA. Injuries to lower limb joints can lead to alterations in movement patterns, which may result in detrimental joint loading. This may be contributing to this accelerated development of PTOA. Older age, independent of OA, is also associated with gait alterations as well as greater metabolic cost of movement and greater fatigability. It is hypothesized that individuals suffering from PTOA as younger adults may be at a greater risk for these metabolic consequences due to the accelerated timeframe of OA onset and associated functional declines of older age. Summary The potential consequences of PTOA in lower limb joints paired with advancing age may include gait abnormalities, greater metabolic cost of movement, greater fatigability, and reduced physical activity. Collectively, these factors may contribute to greater cardiometabolic risk and weight gain, and reduced quality of life with older age. Strategies to alleviate and/or delay the progression of OA in younger and middle-aged adults are necessary to help reduce this risk.
... However, wider-than-preferred stride widths have been associated with increased hip abductor activation [15] and metabolic cost [16]. Similarly, excessive lateral COM movement or trunk lean increases metabolic cost and perceived difficulty [17,18], and lateral COM excursion is positively correlated with the metabolic cost of walking for individuals with TFA [19]. ...
Article
Full-text available
Background: Individuals with lower limb amputation commonly exhibit large gait asymmetries that are associated with secondary health issues. It has been shown that they are capable of attaining improved temporal and propulsive symmetry when walking with a powered knee prosthesis and visual feedback, but they perceive this pattern of gait to be more difficult. Rather than improving the efficiency of gait, improved gait symmetry may be increasing individuals' effort associated with maintaining lateral balance. Methods: In this study, we used a simple visual feedback paradigm to increase the prosthesis-side stance time of six individuals with unilateral TFA or KD as they walked on a powered knee prosthesis at their self-selected speed. As they walked more symmetrically, we evaluated changes in medial-lateral center-of-mass excursion, lateral margin of stability, stride width, and hip abductor activity. Results: As the subjects increased their prosthesis-side stance time, their center-of-mass excursion and hip abductor activity significantly increased, while their lateral margin of stability significantly decreased on the prosthesis-side only. Stride width remained relatively unchanged with testing condition. Conclusions: Extended stance time on a powered knee prosthesis (yielding more symmetric gait) challenged the lateral balance of individuals with lower limb amputation. Lateral stability may be a reason they prefer an asymmetric gait, even with more advanced technology. Hip muscular changes post-amputation may contribute to the decline in stability on the prosthesis side. Interventions and advancements in prosthesis control aimed at improving their control of lateral balance may ameliorate the difficulty in walking with improved gait symmetry.
... Increasing trunk sway resulted in higher contralateral external oblique EMG intensity between initial contact and first maximum knee adduction moment presumably needed to control and stabilize the spine and pelvis [20] with greater trunk sway. Although we did not measure muscle activity in all trunk and lower extremity muscles, the observed differences in muscle activity for walking with increased trunk sway may explain previously reported higher energy consumption for walking with increased trunk sway in patients with knee osteoarthritis (9% higher VO 2 ) [29] and healthy participants (11% higher metabolic cost) [30]. ...
Article
The purpose of this study was to test the hypothesis that walking with increased medio-lateral trunk sway is associated with lower external knee adduction moment and lower extremity muscle activation, and higher external ipsilateral trunk moment and trunk muscle activity than walking with normal trunk sway in healthy participants. Fifteen participants performed walking trials with normal and increased medio-lateral trunk sway. Maximum trunk sway, first maximum knee adduction moment, lateral trunk bending moment, and bilateral vastus medialis, vastus lateralis, gluteus medius, rectus abdominis, external oblique and erector spinae muscle activity were computed. Walking with increased trunk sway was associated with lower maximum knee adduction moment (95% confidence interval (CI): 0.50-0.62 Nm/kg vs. 0.62-0.76 Nm/kg; P < .001) and ipsilateral gluteus medius (-17%; P = .014) and erector spinae muscle activity (-24%; P = .004) and greater maximum lateral trunk bending moment (+34%; P < .001) and contralateral external oblique muscle activity (+60%; P = .009). In all participants, maximum knee adduction moment was negatively correlated and maximum trunk moment was positively correlated with maximum trunk sway. The results of this study suggest that walking with increased trunk sway not only reduces the external knee adduction moment but also alters and possibly increases the load on the trunk. Hence, load-altering biomechanical interventions should always be evaluated not only regarding their effects on the index joint but on other load-bearing joints such as the spine.
... These conditions are very prevalent among older adults and are associated with gait modifications and with the use of assistive devices, known to increase the energy expenditure during walking. 32,33 In the disabled group, 38.5% of the participants were regular users of walking assistive devices. A study designed to assess the relationship between the energy cost of walking and physical function in older adults with mobility limitations found that poorer function was associated with higher energy cost of walking, even when controlling for comorbidity and gait speed. ...
Article
Aerobic capacity is essential for physical function. The aims of this study were to identify the peak oxygen consumption (Vo2 peak) and the incremental shuttle walk test (ISWT) distance associated with disability and to develop an equation to predict Vo2 peak, based on the ISWT distance. Fifteen disabled and 13 nondisabled older adults performed the ISWT using a portable telemetric gas analyzer. The Vo2 peak and the distance associated with disability were 15.8 mL/kg/min or less and 230 m or less, respectively. The coefficient of determination from the predictive model was 0.54. The ISWT might be considered to assess aerobic capacity in older adults. Key words: aerobic capacity, disability, incremental shuttle walk test, older adults, Vo2 peak prediction
... These findings are in agreement with previous studies which found inferior to superior decreases in variability of acceleration time series [22]. A possible reason for decreasing variability of acceleration from inferior to superior body segments is to keep the trunk, and therefore the body's center of mass, as stable as possible to minimize energy expenditure during walking [33,34]. Additionally, the trunk has been shown to act as a physical low pass filter that diminishes higher frequency accelerations that can adversely affect the visual and vestibular systems during gait [35,36]. ...
Article
Understanding upper body and lower body segment relationships may be an important step in assessing stability during gait. This study explored the relationship between acceleration patterns at the trunk and at the foot during treadmill walking at self-selected pace in healthy adults. Forty healthy subjects walked on a treadmill for 3 minutes at self-selected speed. Root mean square (RMS) and approximate entropy (ApEn) were derived from the acceleration time series at the trunk and at the foot in the frontal and sagittal plane. RMS of accelerations at the trunk were strongly correlated with RMS values at the foot in the sagittal plane (r=0.883, p<0.01) and in the frontal plane (r=0.811, p<0.01). ApEn values at the trunk were moderately correlated with ApEn values at the foot in the sagittal plane (r=0.603, p<0.01) only. These results show that acceleration variability at the foot is related to acceleration variability at the trunk, specifically that increased variability at the foot is tied to increased variability at the trunk in healthy adults. Portable inertial sensors can potentially be used in any environment including a laboratory, clinic, or at home to measure lower and upper body segment motion, and assessing relationships between upper and lower body motion may provide a more comprehensive evaluation of overall stability.
... If the patients could not achieve the target trunk lean angle, they were provided additional verbal feedback and encouraged to continue to try to reach the target. 10°was chosen as the target lateral trunk lean angle as previous studies have shown significant changes in KAM at this target angle, while maintaining a feasible amount of lateral trunk lean (Clark et al., 2013;Takacs et al., 2014). Trunk marker positional data were streamed from the Vicon Nexus version 2.1.1 software (VICON MX; Vicon Motion Systems, Oxford, MATLAB calculated and displayed the lateral trunk lean angle animation. ...
Article
The biomechanical mechanism of lateral trunk lean gait employed to reduce external knee adduction moment (KAM) for knee osteoarthritis (OA) patients is not well known. This mechanism may relate to the center of mass (COM) motion. Moreover, lateral trunk lean gait may affect motor control of the COM displacement. Uncontrolled manifold (UCM) analysis is an evaluation index used to understand motor control and variability of the motor task. Here we aimed to clarify the biomechanical mechanism to reduce KAM during lateral trunk lean gait and how motor variability controls the COM displacement. Twenty knee OA patients walked under two conditions: normal and lateral trunk lean gait conditions. UCM analysis was performed with respect to the COM displacement in the frontal plane. We also determined how the variability is structured with regards to the COM displacement as a performance variable. The peak KAM under lateral trunk lean gait was lower than that under normal gait. The reduced peak KAM observed was accompanied by medially shifted knee joint center, shortened distance of the center of pressure to knee joint center, and shortened distance of the knee-ground reaction force lever arm during the stance phase. Knee OA patients with lateral trunk lean gait could maintain kinematic synergy by utilizing greater segmental configuration variance to the performance variable. However, the COM displacement variability of lateral trunk lean gait was larger than that of normal gait. Our findings may provide clinical insights to effectively evaluate and prescribe gait modification training for knee OA patients.
Article
Lateral trunk lean (LTL) is a proposed intervention for knee osteoarthritis but increased muscular demands have not been considered. The objective was to compare lower extremity and trunk muscle activation and joint mechanics between normal and increased LTL gait in healthy adults. Participants (n=20, mean age 22 years) were examined under two gait conditions: normal and increased LTL. A motion capture system and force plates sampled at 100 and 2000Hz respectively were used to determine joint angles and external moments including LTL angle and external knee adduction moment (KAM). Surface electromyography, sampled at 2000Hz, measured activation of six trunk/hip muscles bilaterally. Peak LTL angle, peak KAM, gait speed, and mean values from electromyography waveforms were compared between normal and LTL conditions using paired t-tests or 2-way analysis of variance. There was a significant (p<0.05) increase in peak LTL angle, decrease in first but not second peak KAM, and decrease in gait speed during LTL gait. There were significant (p<0.01) increases in external oblique and iliocostalis muscle activation during LTL gait. There was no change in activation for internal oblique, rectus abdominis, longissimus, and gluteus medius. LTL gait decreased early/mid-stance KAM demonstrating its ability to decrease medial compartment knee loading. Increases in external oblique and iliocostalis activation were present but small to moderate in size and unlikely to lead to short term injury. Longitudinal studies should evaluate the effectiveness of increased LTL for knee osteoarthritis and if the increase in muscular demands leads to negative long term side effects.
Article
Objective: To determine (1) if Medial Thrust or Trunk Lean reduces the knee adduction moment (EKAM) the most during gait in patients with medial knee osteoarthritis, (2) if the best overall strategy is the most effective for each patient and (3) if these strategies affect ankle and hip kinetics. Design: Thirty patients with symptomatic medial knee osteoarthritis underwent 3-dimensional gait analysis. Participants received verbal instructions on two gait strategies (Trunk Lean and Medial Thrust) in randomized order after comfortable walking was recorded. The peaks and impulse of the EKAM and strategy-specific kinematic and kinetic variables were calculated for all conditions. Results: Early stance EKAM peak was significantly reduced during Medial Thrust (-29%). During Trunk Lean, early and late stance EKAM peak and EKAM impulse reduced significantly (38%, 21% and -25%, respectively). In 79% of the subjects, the Trunk Lean condition was significantly more effective in reducing EKAM peak than Medial Thrust. Peak ankle dorsi and plantar flexion, knee flexion and hip extension and adduction moments were not significantly increased. Conclusions: Medial Thrust and Trunk Lean reduced the EKAM during gait in patients with knee osteoarthritis. Individual selection of the most effective gait modification strategy seems vital to optimally reduce dynamic knee loading during gait. No detrimental effects on external ankle and hip moments or knee flexion moments were found for these conditions.
Article
The ability to meet high exercise intensities is limited by the increased risk of injury in some clinical populations. Previous studies have linked large tibia peak positive accelerations resulting from running to increased risk of developing lower-extremity injury. The purpose of this study is to determine the feasibility of using a hip flexion feedback system (HFFS) to meet and maintain different exercise intensities while maintaining low tibia axial accelerations. Ten healthy participants were tested on a HFFS test and an independent walking/running test to meet exercise intensities of 40% and 60% of heart rate reserve (HRR). During the HFFS test, the HFFS controlled in real time the exercise intensity by directing individuals to specific maximum hip flexion targets during walking and providing visual information that assists them in maintaining low tibia peak positive accelerations during the initial contact phase. Maximum hip flexion targets during walking are calculated based on real-time readings of the participant’s heart rate. During the independent test, exercise intensity was controlled independently by the participant using treadmill speed. Compared to the independent test, using the HFFS at 60% HRR resulted in similar heart-rate error but lower tibia peak positive accelerations. No differences were observed for the 40% HRR intensity. This paper describes a novel exercise approach that uses the individual’s heart rate to calculate maximal hip flexion targets that an individual should meet during treadmill walking. The HFFS also provides tibia peak positive peak acceleration cues. Therefore, the HFFS can increase and control exercise intensities while maintaining low tibia accelerations. In particular, the HFFS might be an alternative strategy to meet moderate to vigorous exercise intensities in populations at risk of developing lower-extremity injuries.
Article
Despite improvements in pain and function, people who undergo total hip arthroplasty (THR) may not always return to desired levels of physical activity (PA). The factors associated with low activity levels are not fully understood. Abductor weakness and fatigue have both been proposed as factors that limit activity in older adults or people with hip osteoarthritis, but have not been investigated after THR. We hypothesized that abductor weakness and fatigue are associated with lower activity levels in people who have undergone a THR and that fatigue mediates the association between abductor strength and activity. We evaluated 16 subjects (24±10 months post-THR; age 56.8±8.4 yrs; BMI 31±7 kg/m²). Fatigue was assessed using the PROMIS Fatigue Short-form 7a. Peak isometric hip abductor torque was assessed using a dynamometer with subjects in a sidelying position. We assessed activity level using the UCLA activity score. We used Pearson correlations to explore the associations among the variables. Next we used a three-step linear regression procedure to test whether or not fatigue acted as a mediator between abductor torque and UCLA activity scores. Higher abductor torque was associated with less fatigue (R²=0.275; p=0.037) and with higher UCLA scores (R²=0.488, p=0.003). Higher fatigue was associated with lower UCLA scores (R² = 0. 307, p = 0.017), however there was no evidence of mediation. This suggests that addressing both abductor strength and fatigue may increase physical activity. Statement of Clinical Significance: Fatigue and abductor weakness should be evaluated in sedentary THR patients presenting for long-term follow up. This article is protected by copyright. All rights reserved
Article
Background Aberrant biomechanics may influence osteoarthritis-associated physical activity limitations. Our purpose was to evaluate the association of walking energetics, fatigue, and fatigability on physical activity in people with knee osteoarthritis. We hypothesized that using increased energy for walking, experiencing more fatigue, or being more fatigable are associated with less activity, and that fatigue and fatigability mediate the relationships between walking energetics and physical activity. Methods We tested our hypothesis in 30 people with knee osteoarthritis (age 58 ± 9 years, 10 Male/20 Female). Physical activity was assessed using the University of California Los Angeles score. We used a six-minute walk test to predict VO2max. Next we used a portable oxygen exchange system to measure relative energy used (100 * VO2rate/VO2max) and VO2cost during walking at preferred speeds. We used the Knee injury and Osteoarthritis Outcome Score subscale to quantify pain, and the Patient Reported Outcome Measurement Instrument System Fatigue survey and a treadmill-based fatigability test to assess fatigue and fatigability. Spearman correlations, regression, and mediation analysis were used to test our hypotheses. Findings Greater energy used during walking, fatigue, and fatigability were all associated with lower physical activity (rho = −0.585 to −0.379, P = 0.001 to 0.043). These associations persisted when incorporating pain into the models. Fatigue and fatigability mediated the associations between walking energetics and physical activity. Interpretation Walking energetics could be a useful target to promote physical activity in people with osteoarthritis. Further, the effect of walking energetics on physical activity may work through its impact on fatigability.
Article
Background: The choice of surgical approach for total hip arthroplasty (THA) remains a contentious issue with regards to clinical outcome optimization and restoring patient function. The purpose of this study was to determine the impact of surgical approach for THA on quantitative gait analysis. Methods: Patients undergoing THA for primary osteoarthritis of the hip were assigned to 1 of 3 surgical approaches: anterior, posterior and lateral. Standardized implants were used at the time of surgery. Three-dimensional gait analysis was performed preoperatively and at 6 and 12 weeks postoperatively. At each time point, we compared temporal parameters, kinematics and kinetics. Results: We included 30 patients in our analysis (10 anterior, 10 posterior, and 10 lateral). The groups were similar with respect to age (p = 0.27), body mass index (p = 0.16), and Charlson Comorbidity Index score (p = 0.66). Temporal parameters were similar among the groups at all time points. The lateral cohort had higher pelvic tilt during stance on the affected leg than the anterior cohort at 6 weeks (p = 0.041). Affected leg ipsilateral trunk lean during stance was higher in the lateral group than in the other cohorts at 6 weeks (p = 0.008) and 12 weeks (p = 0.040). The anterior and posterior groups showed increased external rotation at 6 weeks (p = 0.003) and 12 weeks (p = 0.012) compared with the lateral group. Conclusion: Temporal gait parameters were similar following THA for all approaches. Differences in gait kinematics and kinetics exist; however, given the small absolute differences, the clinical importance of these changes remains undetermined.
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Comparative analysis of effects of a stationary cycle and motorized treadmill in improving the functional status of patients with knee osteoarthritis.
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Objectives: To review the literature regarding gait retraining to reduce knee adduction moments and their effects on hip and ankle biomechanics. Data sources: Twelve academic databases were searched from inception to January 2019. Key words "walk*" OR "gait," "knee" OR "adduction moment," "osteoarthriti*" OR "arthriti*" OR "osteo arthriti*" OR "OA," and "hip" OR "ankle" were combined with conjunction "and" in all fields. Study selection: Abstracts and full-text articles were assessed by 2 individuals against a predefined criterion. Data synthesis: Of the 11 studies, sample sizes varied from 8-40 participants. Eight different gait retraining styles were evaluated: hip internal rotation, lateral trunk lean, toe-in, toe-out, increased step width, medial thrust, contralateral pelvic drop, and medial foot weight transfer. Using the Black and Downs tool, the methodological quality of the included studies was fair to moderate ranging between 12 of 25 to 18 of 28. Trunk lean and medial thrust produced the biggest reductions in first peak knee adduction moment. Studies lacked collective sagittal and frontal plane hip and ankle joint biomechanics. Generally, studies had a low sample size of healthy participants with no osteoarthritis and assessed gait retraining during 1 laboratory visit while not documenting the difficulty of the gait retraining style. Conclusions: Gait retraining techniques may reduce knee joint loading; however, the biomechanical effects to the pelvis, hip, and ankle is unknown, and there is a lack of understanding for the ease of application of the gait retraining styles.
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Background: The choice of surgical approach for total hip arthroplasty (THA) remains a contentious issue with regards to clinical outcome optimization and restoring patient function. The purpose of this study was to determine the impact of surgical approach for THA on quantitative gait analysis. Methods: Patients undergoing THA for primary osteoarthritis of the hip were assigned to 1 of 3 surgical approaches: anterior, posterior and lateral. Standardized implants were used at the time of surgery. Three-dimensional gait analysis was performed preoperatively and at 6 and 12 weeks postoperatively. At each time point, we compared temporal parameters, kinematics and kinetics. Results: We included 30 patients in our analysis (10 anterior, 10 posterior, and 10 lateral). The groups were similar with respect to age (p = 0.27), body mass index (p = 0.16), and Charlson Comorbidity Index score (p = 0.66). Temporal parameters were similar among the groups at all time points. The lateral cohort had higher pelvic tilt during stance on the affected leg than the anterior cohort at 6 weeks (p = 0.041). Affected leg ipsilateral trunk lean during stance was higher in the lateral group than in the other cohorts at 6 weeks (p = 0.008) and 12 weeks (p = 0.040). The anterior and posterior groups showed increased external rotation at 6 weeks (p = 0.003) and 12 weeks (p = 0.012) compared with the lateral group. Conclusion: Temporal gait parameters were similar following THA for all approaches. Differences in gait kinematics and kinetics exist; however, given the small absolute differences, the clinical importance of these changes remains undetermined.
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Osteoarthritis (OA) is the most frequent cause of disability in the United States, with the medial compartment of the knee being most commonly affected. The initiation and progression of knee OA is influenced by many factors, including kinematics. In response to loading during weight-bearing activity, cartilage in healthy knees demonstrates spatial adaptations in morphology and mechanical properties. These adaptations allow certain regions of the cartilage to respond to loading; other regions are less well suited to accommodate loading. Alterations in normal knee kinematics shift loading from cartilage regions adapted for loading to regions less well suited for loading, which leads to the initiation and progression of degenerative processes consistent with knee OA. Kinematic variables that are associated with the development, progression, and severity of knee OA are the adduction moment and tibiofemoral rotation. Because of its strong correlation with disease progression and pain, the peak adduction moment during gait has been identified as a target for treatment design. Gait modification offers a noninvasive option for seeking significant reductions. Gait modification has the potential to reduce pain and slow the progression of medial compartment knee OA.
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To assess the impact of daily cane use during gait in relation to pain, function, general health and energy expenditure among patients with knee osteoarthritis. Sixty-four patients were randomly assigned to an experimental group (EG) or control group (CG). The EG used a cane every day for 2 months, whereas the CG did not use a cane in this period. The first outcome was pain and the second were function (Lequesne and WOMAC), general health (SF-36) and energy expenditure (gas analysis during the 6-minute walk test (6MWT) with and without a cane). Evaluations were performed at baseline, 30 and 60 days. The groups were homogeneous for all parameters at baseline. Compared with the CG, the EG significantly improved pain (ES 0.18), function - Lequesne (ES 0.13), some domains of SF-36 (role physical, ES 0.07 and bodily pain, ES 0.08) and distance on the 6MWT with the cane (ES 0.16). At the end of the 6MWT with the cane, the EG significantly improved energy expenditure (ES 0.21), carbon dioxide production (ES 0.12) and metabolic equivalents (ES 0.15) compared with the CG. A cane can be used to diminish pain, improve function and some aspects of quality of life in patients with knee osteoarthritis. The prescription of a cane should take into account the substantial increase in energy expenditure in the first month of use, whereas energy expenditure is no longer a factor for concern by the end of the second month due to adaptation to cane use. The trial was registered in clinicaltrials.gov (NCT00698412).
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The purpose of this investigation was to study the relationship between perceptual ratings from Borg's new category-ratio scale and some physiological variables during exercise. To accomplish this, scale ratings were related to blood and muscle lactate accumulation and heart rates during a progressive, maximal exercise test on the cycle ergometer. Ten physically active males were utilized as subjects; lactate data were recorded on only 7 of the 10 subjects. Three ratings of perceived exertion were made at each stage of the exercise test: leg effort (LE), cardiorespiratory effort (CE), and leg pain (LP). All ratings showed a positively accelerating increase with exercise intensity as did both blood and muscle lactate, while heart rate increased linearly. The exponents of the power functions describing the perceptual variation ranged from 1.63-1.67 compared to 2.2 for blood lactate and 2.7 for muscle lactate. Polynomial analysis revealed a similar quadratic trend for both perceptual and blood lactate data; however, muscle lactate demonstrated a cubic trend. No significant differences were found between CE and LE at 100, 200, and 300 W (P greater than 0.05). Subjects with the highest percentage of slow-twitch muscle fibers (mean ST%=51.14) rated LE and CE significantly lower ( mean of all power outputs, 0-300 W) than those with the lowest ST% (mean=34.52). It is concluded that the ratings from the category-ratio scale correspond very well with glycogenolytic metabolism leading to lactate accumulation during exercise.
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People with osteoarthritis (OA) of the knee who have pain generally exhibit decreased activity and physical deconditioning. This study investigated the effects of mechanical unweighting on knee pain and exercise responses in people with OA of the knee who have pain. Four men and 23 women, with a mean age of 67.9 years (SD = 11.3, range = 50-88) and having a 12-year average duration of knee OA, participated. A mechanical unloading device enabled subjects to perform a modified Naughton treadmill exercise test at 0%, 20%, and 40% of body weight support (BWS). Oxygen consumption (VO2), heart rate (HR), and perceived pain were measured during the last minute of each exercise stage. Mechanical unweighting at 20% and 40% BWS decreased the Vo2 and HR responses to treadmill exercise but did not decrease knee pain during walking in this sample. These findings indicate that treadmill exercise accompanied by BWS permits recommended training intensities to be obtained in elderly people with OA, but may not provide pain relief in this group.
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We provide an updated version of the Compendium of Physical Activities, a coding scheme that classifies specific physical activity (PA) by rate of energy expenditure. It was developed to enhance the comparability of results across studies using self-reports of PA. The Compendium coding scheme links a five-digit code that describes physical activities by major headings (e.g., occupation, transportation, etc.) and specific activities within each major heading with its intensity, defined as the ratio of work metabolic rate to a standard resting metabolic rate (MET). Energy expenditure in MET-minutes, MET-hours, kcal, or kcal per kilogram body weight can be estimated for specific activities by type or MET intensity. Additions to the Compendium were obtained from studies describing daily PA patterns of adults and studies measuring the energy cost of specific physical activities in field settings. The updated version includes two new major headings of volunteer and religious activities, extends the number of specific activities from 477 to 605, and provides updated MET intensity levels for selected activities.
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To test the hypothesis that dynamic load at baseline can predict radiographic disease progression in patients with medial compartment knee osteoarthritis (OA). During 1991-93 baseline data were collected by assessment of pain, radiography, and gait analysis in 106 patients referred to hospital with medial compartment knee OA. At the six year follow up, 74 patients were again examined to assess radiographic changes. Radiographic disease progression was defined as more than one grade narrowing of minimum joint space of the medial compartment. In the 32 patients showing disease progression, pain was more severe and adduction moment was higher at baseline than in those without disease progression (n=42). Joint space narrowing of the medial compartment during the six year period correlated significantly with the adduction moment at entry. Adduction moment correlated significantly with mechanical axis (varus alignment) and negatively with joint space width and pain score. Logistic regression analysis showed that the risk of progression of knee OA increased 6.46 times with a 1% increase in adduction moment. The results suggest that the baseline adduction moment of the knee, which reflects the dynamic load on the medial compartment, can predict radiographic OA progression at the six year follow up in patients with medial compartment knee OA.
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To compare the energy expenditure in patients with unilateral knee osteoarthritis while walking with canes of different lengths. A quasi-experimental study (single-group) was carried out on thirty patients with unilateral knee osteoarthritis. An adjustable aluminum cane was used, and three different cane lengths were determined for each subject: C1--length from the floor to the greater trochanter; C2--length from the floor to the distal wrist crease; and C3--length obtained by the formula: height x 0.45 + 0.87 m. Resting and walking heart rates were measured with a Polar hear rate meter. Walking speed was calculated by the time required for the patient to walk 10 m. Gait energy cost was estimated using the physiological cost index, and results were compared. The sample consisted of 25 women and five men (average age of 68 years). Statistically significant differences in physiological cost index measurements were observed between unassisted walking and assisted walking with a cane of any length (p<0.001), as well as between walking with a C2-length cane and unassisted walking, and walking with a C1-length cane and walking with a C3-length cane (p=0.001; p = 0.037; p=0.001; respectively). These data demonstrate that small alterations in the length of canes used for weight-bearing ambulation in patients with unilateral knee osteoarthritis increase the energy expenditure measured by the physiological cost index during walking. Further studies are needed for a more precise quantification of the increase in energy expenditure during cane-assisted gait and an assessment of the effectiveness of cane use in relieving pain and improving function in patients with knee osteoarthritis.
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Although lower limb strength becomes asymmetrical with age, past studies of aging effects on gait biomechanics have usually analyzed only one limb. This experiment measured how aging and treadmill surface influenced both dominant and nondominant step parameters in older (mean 74.0 y) and young participants (mean 21.9 y). Step-cycle parameters were obtained from 3-dimensional position/time data during preferred-speed walking for 40 trials along a 10 m walkway and for 10 minutes of treadmill walking. Walking speed (young 1.23 m/s, older 1.24 m/s) and step velocity for the two age groups were similar in overground walking but older adults showed significantly slower walking speed (young 1.26 m/s, older 1.05 m/s) and step velocity on the treadmill due to reduced step length and prolonged step time. Older adults had shorter step length than young adults and both groups reduced step length on the treadmill. Step velocity and length of older adults' dominant limb was asymmetrically larger. Older adults increased the proportion of double support in step time when treadmill walking. This adaptation combined with reduced step velocity and length may preserve balance. The results suggest that bilateral analyses should be employed to accurately describe asymmetric features of gait especially for older adults.
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This study examined the influence of a 6-week gait retraining program on the knee adduction moment (KAM) and knee pain and function. Ten subjects with medial compartment knee osteoarthritis and self-reported knee pain participated in weekly gait retraining sessions over 6 weeks. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and a 10-point visual-analog pain scale score were measured at baseline, post-training (end of 6 weeks), and 1 month after training ended. Gait retraining reduced the first peak KAM by 20% (p < 0.01) post-training as a result of a 7° decrease in foot progression angle (i.e., increased internal foot rotation), compared to baseline (p < 0.01). WOMAC pain and function scores were improved at post-training by 29% and 32%, respectively (p < 0.05) and visual-analog pain scale scores improved by two points (p < 0.05). Changes in WOMAC pain and function were approximately 75% larger than the expected placebo effect (p < 0.05). Changes in KAM, foot progression angle, WOMAC pain and function, and visual-analog pain score were retained 1 month after the end of the 6-week training period (p < 0.05). These results show that a 6-week gait retraining program can reduce the KAM and improve symptoms for individuals with medial compartment knee osteoarthritis and knee pain. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res XX:XXX-XXX, 2013.
Article
Objective: The adduction moment at the knee during gait is the primary determinant of medial-to-lateral load distribution. If the adduction moment contributes to progression of osteoarthritis (OA), then patients with advanced medial tibiofemoral OA should have higher adduction moments. The present study was undertaken to investigate the hypothesis that the adduction moment normalized for weight and height is associated with medial tibiofemoral OA disease severity after controlling for age, sex, and pain level, and to examine the correlation of serum hyaluronan (HA) level with disease severity and with the adduction moment in a subset of patients. Methods: Fifty-four patients with medial tibiofemoral OA underwent gait analysis and radiographic evaluation. Disease severity was assessed using the Kellgren-Lawrence (K-L) grade and medial joint space width. In a subset of 23 patients with available sera, HA was quantified by sandwich enzyme-linked immunosorbent assay. Pearson correlations, a random effects model, and multivariate regression models were used. Results: The adduction moment correlated with the K-L grade in the left and right knees (r = 0.68 and r = 0.60, respectively), and with joint space width in the left and right knees (r = -0.45 and r = -0.47, respectively). The relationship persisted after controlling for age, sex, and severity of pain. The partial correlation between K-L grade and adduction moment was 0.71 in the left knees and 0.61 in the right knees. For every 1.0-unit increase in adduction moment, there was a 0.63-mm decrease in joint space width. In the subset of patients in whom serum HA levels were measured, HA levels correlated with medial joint space width (r = -0.55), but not with the adduction moment. Conclusion: There is a significant relationship between the adduction moment and OA disease severity. Serum HA levels correlate with joint space width but not with the adduction moment. Longitudinal studies will be necessary to determine the contribution of the adduction moment, and its contribution in conjunction with metabolic markers, to progression of medial tibiofemoral OA.
Article
To evaluate whether increased lateral trunk lean toward the symptomatic lower extremity during gait in people with medial knee osteoarthritis (OA) immediately alters symptoms or medial knee load, as measured by the external knee adduction moment (KAM). Participants with medial knee OA (n = 22) underwent 3-dimensional gait analysis to measure KAM peaks (early and late stance) and KAM impulse. Following the analysis of natural gait, participants were trained to lean their trunk toward the symptomatic leg during ipsilateral stance over 3 randomly ordered conditions (6°, 9°, and 12° lean). A projection screen displayed real-time trunk angles and target levels. Pain/discomfort in the knees, the hip, and the back were measured across conditions. Load-modifying effects of increasing lean magnitudes were investigated using linear mixed models. Mediating effects of peak lean timing and participant characteristics (pain and malalignment) were evaluated. Increased trunk lean reduced all KAM measures (P < 0.001), with larger lean angles achieving greater reductions. Efficacy of load reduction improved with later peak lean timing for all measures of the KAM. Participant characteristics did not mediate the effect of trunk lean on the KAM, and symptoms did not change across conditions (P > 0.05). Increased trunk lean reduced medial knee load in a dose-response manner. Slightly later achievement of peak trunk lean improved the load-modifying effect of this gait strategy. No immediate symptomatic changes were identified. Future research should determine if long-term implementation of this gait strategy is feasible and whether it can modify disease symptoms and OA progression.
Article
The purpose of this study was to determine the contribution of changes in amplitude and phasing of medio-lateral trunk sway to a change in the knee adduction moment when walking with increased medio-lateral trunk sway. Kinematic and kinetic data of walking trials with normal and with increased trunk sway were collected for 19 healthy volunteers using a standard motion analysis system. The relationship between the change in first peak knee adduction moment (ΔKAM) and change in trunk sway amplitude (ΔSA; difference between maximum contralateral trunk lean and maximum ipsilateral trunk lean) and phasing (SP; time of heel-strike relative to time of maximum contralateral and time of maximum ipsilateral trunk lean) was determined using nonlinear regression analysis. On average, subjects increased their SA by 9.7 ± 3.6 deg (P < 0.001) with an average SP of 98.8 ± 88.8 ms resulting in an average reduction in the first peak knee adduction moment of -55.2 ± 30.3% (P < 0.001). 64.3% of variability in change in peak knee adduction moment with the increased trunk sway condition was explained by both differences in SA and SP, and the relationship among these parameters was described by the regression equation ΔKAM = 27.220-4.128 [middle dot] ΔSA-64.785 [middle dot] cos(SP). Hence, not only the amplitude but also the phasing of trunk motion is critical. Not only lower limb movement but also lumbar and thoracic lateral flexion should be considered in the decision making process for an optimal intervention aimed at reducing the load on the medial compartment of the knee during walking. However, these promising findings originated from studies on healthy subjects and their relevance for gait training interventions in patients with presumably painful knee osteoarthritis remains to be determined.
Article
To compare the time-varying behavior of maximum toe-out angle, lateral trunk lean (over the stance leg), and pelvic obliquity (rise and drop on the swing leg) during prolonged walking in participants with and without medial compartment knee osteoarthritis (OA), and to explore correlations between these gait characteristics and pain. Twenty patients with knee OA and 20 healthy controls completed 30 minutes of treadmill walking. Toe-out, trunk lean, pelvic obliquity, and pain were measured at 5-minute intervals. The mean ± SD toe-out angle was significantly smaller (P = 0.04) in patients with knee OA (6.7 ± 2.5 degrees) than in controls (10.3 ± 2.2 degrees). Toe-out changed significantly over time (P = 0.002), but not in a systematic way, and there was no interaction between group and time. The mean ± SD trunk lean was higher (P = 0.03) in patients with knee OA (2.0 ± 1.0 degrees) than in controls (0.7 ± 0.5 degrees). Trunk lean did not change over time and there was no interaction between group and time. There were no differences for pelvic drop. The mean ± SD pelvic rise was higher (P = 0.01) in patients with knee OA (2.8 ± 0.9 degrees) than in controls (1.2 ± 0.8 degrees), but did not change over time and there was no interaction. Patients experienced a small increase in pain (P < 0.001). Trunk lean and pelvic drop were correlated with pain (r = 0.49, P = 0.03 and r = 0.47, P = 0.04, respectively). Toe-out and trunk lean are consistently different between individuals with and without medial compartment knee OA during prolonged walking, and patients with greater pain have greater trunk lean. However, over 30 minutes of walking, these gait characteristics remain quite stable, suggesting they are not acute compensatory mechanisms in response to repetitive loading with subtle increases in pain.
Article
To investigate the relative roles of mechanically imposed and physiologically imposed stiff-knee gait (SKG) patterns on energy cost. Repeated-measures, within-subjects design. Research laboratory. Individuals (N=20) without musculoskeletal, neuromuscular, or cardiorespiratory limitations. Participants walked on an instrumented treadmill at their self-selected overground gait speed for 3 randomly ordered conditions: (1) control, (2) mechanically imposed stiff-knee gait (SKG-M) using a lockable knee brace, and (3) physiologically imposed stiff-knee gait (SKG-P) using electrical stimulation to the quadriceps. Each condition was performed with 0% and 20% body weight support. Indirect calorimetry determined net metabolic power, and motion capture measured lower extremity joint kinematics and kinetics. Net metabolic power, knee flexion angle, circumduction, hip hiking, and hip flexion and ankle plantarflexion moments. Participants walked at 1.25±.09m/s. Net metabolic power was significantly increased by 17% in SKG-M and 37% in SKG-P compared with control (mean increase: .66±.60W/kg for SKG-M; 1.39±.79W/kg for SKG-P; both P<.001). Furthermore, SKG-P required greater net metabolic power than SKG-M (P<.001). Simulated SKG was associated with increased circumduction and hip hiking. Despite no change in ankle plantarflexion moments (P=.280), the hip flexion moment was increased during SKG-P (.43±.15Nm/kg·m) compared with control (.31±.08Nm/kg·m; P<.001). The increase in energy cost associated with simulated SKG was due in part to abnormal mechanical compensations, and in part to an increase in quadriceps activity. Understanding the mechanisms underlying the increase in quadriceps activity will enable a reduction in the energy cost of walking with SKG.
Article
The aim of the present study was to assess the immediate impact of cane use on energy expenditure during gait in patients with knee OA analyzing VO(2). An observational, cross-sectional study was carried out on 64 symptomatic patients with a diagnosis of knee OA. The assessment of energy expenditure was performed through an analysis of expired gases using the portable K4 apparatus (Cosmed, Model K4 b2, Italy) during the six-min walk test (6MWT). Two tests were performed with a cane and two without a cane on two different days within a seven-day period. The patients walked farther on the test without the cane (p<0.001). Oxygen expenditure (VO(2)) and the O(2) cost of walking at the end of the 6MWT increased approximately 50% and 80% during cane-assisted gait when compared to gait without the use of a cane (p<0.001). Pain (Borg scale) decreased approximately 20% at the end of the 6MWT with cane-assisted gait in comparison to gait without a cane (p<0.001). Cane use causes an immediate increase in energy expenditure (VO(2)) during gait and O(2) cost of walking and an immediate decrease of pain during gait. It is necessary to do a more prolonged follow up in order to assess the impact of daily cane use on energy expenditure among these patients and determine whether adaptation occurs. Furthermore, it is necessary to study whether daily cane use has a positive impact on important parameters in these patients, such as pain, function and quality of life.
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The Compendium of Physical Activities was developed to enhance the comparability of results across studies using self-report physical activity (PA) and is used to quantify the energy cost of a wide variety of PA. We provide the second update of the Compendium, called the 2011 Compendium. The 2011 Compendium retains the previous coding scheme to identify the major category headings and specific PA by their rate of energy expenditure in MET. Modifications in the 2011 Compendium include cataloging measured MET values and their source references, when available; addition of new codes and specific activities; an update of the Compendium tracking guide that links information in the 1993, 2000, and 2011 compendia versions; and the creation of a Web site to facilitate easy access and downloading of Compendium documents. Measured MET values were obtained from a systematic search of databases using defined key words. The 2011 Compendium contains 821 codes for specific activities. Two hundred seventeen new codes were added, 68% (561/821) of which have measured MET values. Approximately half (317/604) of the codes from the 2000 Compendium were modified to improve the definitions and/or to consolidate specific activities and to update estimated MET values where measured values did not exist. Updated MET values accounted for 73% of all code changes. The Compendium is used globally to quantify the energy cost of PA in adults for surveillance activities, research studies, and, in clinical settings, to write PA recommendations and to assess energy expenditure in individuals. The 2011 Compendium is an update of a system for quantifying the energy cost of adult human PA and is a living document that is moving in the direction of being 100% evidence based.
Article
The purpose of this feasibility study was to examine changes in frontal plane knee and hip walking biomechanics following a gait retraining strategy focused on increasing lateral trunk lean and to quantify reports of difficulty and joint discomfort when performing such a gait modification. After undergoing a baseline analysis of normal walking, 9 young, healthy participants were trained to modify their gait to exhibit small (4°), medium (8°), and large (12°) amounts of lateral trunk lean. Training was guided by the use of real-time biofeedback of the actual trunk lean angle. Peak frontal plane external knee and hip joint moments were compared across conditions. Participants were asked to report the degree of difficulty and the presence of any joint discomfort for each amount of trunk lean modification. Small (4°), medium (8°), and large (12°) amounts of lateral trunk lean reduced the peak external knee adduction moment (KAM) by 7%, 21%, and 25%, respectively, though the peak KAM was only significantly less in the medium and large conditions (p<0.001). Increased trunk lean also significantly reduced the peak external hip adduction moments (p<0.001). All participants reported at least some difficulty performing the exaggerated trunk lean pattern and three participants reported ipsilateral knee, hip, and/or lower spine discomfort. Results from this study indicate that a gait pattern with increased lateral trunk lean can effectively reduce frontal plane joint moments. Though these findings have implications for pathological populations, learning this gait pattern was associated with some difficulty and joint discomfort.
Article
To evaluate the effect of gait modification strategies on the external knee adduction moment (KAM), a marker of medial knee joint load; determine potentially adverse effects; assess the methodologic quality; and identify areas of future research. Five electronic databases were searched. Studies evaluating the effects of gait modifications on the KAM in either healthy individuals or those with knee osteoarthritis (OA) were included. Methodologic quality was evaluated by 2 reviewers using the Downs and Black checklist. Twenty-four studies met the inclusion criteria, exploring 14 different gait modifications of varying sample sizes, age groups, and OA classifications. Contralateral cane use, increased step width, medial knee thrust, increased hip internal rotation, weight transfer to the medial foot, and increased lateral trunk lean demonstrated KAM reductions. Tai Chi gait, ipsilateral cane use, Nordic walking poles, and increased knee flexion exhibited increases in the KAM, demonstrating a potential detriment to their use. The effects of reduced stride length, as well as increases and reductions in either toe-out or gait speed, were inconsistent across the studies and gait cycle. This review demonstrates that some gait modifications have the ability to alter knee load. Future research is required to determine the magnitude of modification required to maximize beneficial effects, the best method of training, long-term patient adherence, and if these biomechanical changes can translate into clinically relevant changes in symptoms or disease progression risk.
Article
To review the role of biomechanics in the pathogenesis of lower-extremity osteoarthritis and recent advances in biomechanically active intervention strategies for osteoarthritis. The conventional approach to treating knee osteoarthritis with analgesics and physical therapy has not been shown to alter the natural history of the disease, suggesting that novel strategies are necessary. Progression of lower-extremity osteoarthritis is mediated by aberrant biomechanics, which can be assessed using gait analyses and validated markers of dynamic knee loading such as the peak adduction moment (AddM) and adduction angular impulse (AddImp). Recognition of the mechanical component of osteoarthritis progression has led to intervention strategies that seek to reduce functional loads at the knee, and thereby, potentially, to palliate pain and retard disease progression. Biomechanically active interventions have been demonstrated to reduce dynamic loading of the knees in patients with osteoarthritis, and are potentially promising strategies to treat symptoms as well as to alter disease progression in osteoarthritis.
Article
A simple external marker system and algorithms for computing lower extremity joint angle motion during level walking were developed and implemented on a computer-aided video motion analysis system (VICON). The concept of embedded axes and Euler rotation angles was used to define the three-dimensional joint angle motion based on a set of body surface markers. Gait analysis was performed on 40 normal young adults three times on three different test days at least 1 week apart using the marker system. Angular motion of the hip, knee, and ankle joints and of the pelvis were obtained throughout a gait cycle utilizing the three-dimensional trajectories of markers. The effect of uncertainties in defining the embedded axis on joint angles was demonstrated using sensitivity analysis. The errors in the estimation of joint angle motion were quantified with respect to the degree of error in the construction of embedded axes. The limitations of the model and the marker system in evaluating pathologic gait are discussed. The relatively small number of body surface markers used in the system render it easy to implement for use in routine clinical gait evaluations. Additionally, data presented in this paper should be a useful reference for describing and comparing pathologic gait patterns.
Article
Physiological energy expenditure measurement has proven to be a reliable method of quantitatively assessing the penalties imposed by gait disability. The purpose of this review is to outline the basic principles of exercise physiology relevant to human locomotion; detail the energy expenditure of normal walking; and summarize the results of energy expenditure studies performed in patients with specific neurologic and orthopedic disabilities. The magnitude of the disabilities and the patients' capacity to tolerate the increased energy requirements are compared. This paper also will examine the effectiveness of rehabilitation interventions at mitigating the energetic penalties of disability during ambulation.
Article
Osteoarthritic knee pain affects patient mobility. Relief of knee pain in osteoarthritis has been reported to increase loading of the knee during gait, but it is unknown whether such pain relief enhances knee loading during more demanding activities such as stair-stepping. The gait of 19 patients and stair-stepping of 14 patients with painful medial compartment osteoarthritis of the knee was assessed before and after pain-relieving intraarticular injection of the knee and compared with those of 21 healthy control subjects. There were significant increases in gait velocity, cadence, maximum external knee adduction moment (indicating increased loading in the medial compartment of the knee), and maximum external hip adduction and ankle abduction moments immediately after the injection. With the exception of velocity and ankle abduction moment, these variables were returned to levels that were not statistically different from those of the control subjects. However, no significant differences were found during stair-stepping in the external adduction-abduction moments about the knee, hip, or ankle after injection. Furthermore, the postinjection magnitudes of these variables during stair-stepping were significantly less than those of the controls. Therefore, although the relief of knee pain is sufficient to enhance gait function in osteoarthritis of the knee, it is insufficient to enhance stair-stepping function.
Article
This review examines recent in-vivo studies of ambulation and discusses the fundamental role of mechanics of ambulation in the initiation and progression of osteoarthritis at the knee. Recent studies have supported earlier findings that a high adduction moment at the knee during ambulation was most frequently reported to influence the progression of medial compartment osteoarthritis. In contrast to previous findings in patients with osteoarthritis, recent work on healthy subjects reports that cartilage thickness increases with high ambulatory loads. Kinematic changes were associated with the initiation of osteoarthritis. Recent studies of subjects with high risk factors for knee osteoarthritis (obesity and anterior cruciate ligament injury) reported a relationship between kinematic changes during ambulation and the initiation of osteoarthritis at the knee. This review also contrasts the relative influence on osteoarthritis of knee mechanics measured during ambulatory and nonambulatory activities. The initiation of osteoarthritis occurs when healthy cartilage experiences some condition (traumatic or chronic) that causes kinematic changes during ambulation at the knee to shift the load-bearing contact location of the joint to a region not conditioned to the new loading. The rate of progression of osteoarthritis is associated with increased load during ambulation.
Article
The external knee adduction torque has been proposed as a surrogate measure for medial compartment load during gait. However, a direct link between these two quantities has not been demonstrated using in vivo measurement of medial compartment load. This study uses in vivo data collected from a single subject with an instrumented knee implant to evaluate this link. The subject performed five different overground gait motions (normal, fast, slow, wide, and toe-out) with simultaneous collection of instrumented implant, video motion, and ground reaction data. For each trial, the knee adduction torque was measured externally while the total axial force applied to the tibial insert was measured internally. Based on data collected from the same subject performing treadmill gait under fluoroscopic motion analysis, a regression equation was developed to calculate medial contact force from the implant load cell measurements. Correlation analyses were performed for the stance phase and entire gait cycle to quantify the relationship between the knee adduction torque and both the medial contact force and the medial to total contact force ratio. When the entire gait cycle was analyzed, R(2) for medial contact force was 0.77 when all gait trials were analyzed together and between 0.69 and 0.93 when each gait trial was analyzed separately (p < 0.001 in all cases). For medial to total force ratio, R(2) was 0.69 for all trials together and between 0.54 and 0.90 for each trial separately (p < 0.001 in all cases). When only the stance phase was analyzed, R(2) values were slightly lower. These results support the hypothesis that the knee adduction torque is highly correlated with medial compartment contact force and medial to total force ratio during gait.
Article
To estimate the test-retest reliability of the peak external knee adduction moment during walking in patients with medial compartment knee osteoarthritis (OA), and to describe the interpretation of the reported values. A total of 31 patients diagnosed with knee OA confined primarily to the medial compartment underwent quantitative gait analyses during 2 separate test sessions at least 24 hours apart and within 1 week. The peak knee adduction moment was calculated for each patient at each session based on the mean of 5 walking trials. Reliability was estimated using the intraclass correlation coefficient (ICC(2,1)) and the standard error of measurement (SEM). The mean difference in peak adduction moments between test sessions was 0.1% body weight x height (BW x ht; 95% confidence interval [95% CI] -0.1, 0.3). The point estimate for the ICC was 0.86 (95% CI 0.73, 0.96). The point estimate for the SEM was 0.36% BW x ht (95% CI 0.29, 0.48). The ICC suggests that the peak knee adduction moment is appropriate for use when distinguishing among patients, for example, in studies of various interventions intended to decrease dynamic load on the knee medial compartment. The SEM illustrates the importance of considering measurement error and incorporating confidence levels when interpreting an individual patient's peak knee adduction moment value.
Article
The purposes of this study was to test a mechanism to reduce the knee adduction moment by testing the hypothesis that increased medio-lateral trunk sway can reduce the knee adduction moment during ambulation in healthy subjects, and to examine the possibility that increasing medio-lateral trunk sway can produce similar potentially adverse secondary gait changes previously associated with reduced knee adduction moments in patients with knee osteoarthritis. Nineteen healthy adults performed walking trials with normal and increased medio-lateral trunk sway at a self-selected normal walking speed. Standard gait analysis was used to calculate three-dimensional lower extremity joint kinematics and kinetics. Knee and hip adduction moments were lower (-65.0% and -57.1%, respectively) for the increased medio-lateral trunk sway trials than for the normal trunk sway trials. Knee flexion angle at heel-strike was 3 degrees higher for the increased than for the normal trunk sway trials. Knee and hip abduction moments were higher for the increased medio-lateral trunk sway trials, and none of the other variables differed between the two conditions. Walking with increased medio-lateral trunk sway substantially reduces the knee adduction moment during walking in healthy subjects without some of the adverse secondary effects such as increased axial loading rates at the major joints of the lower extremity. This result supports the potential of using gait retraining for walking with increased medio-lateral trunk sway as treatment for patients with degenerative joint disease such as medial compartment knee osteoarthritis.
Article
To test the hypothesis that selected gait kinematics, particularly lateral trunk lean, observed in patients with medial compartment knee osteoarthritis explain variation in dynamic knee joint load. In this cross-sectional observational study, 120 patients with radiographically confirmed varus gonarthrosis underwent three-dimensional gait analysis at their typical walking speed. We used sequential (hierarchical) linear regression to examine the amount of variance in dynamic knee joint load (external knee adduction moment) explained by static lower limb alignment (mechanical axis angle) and gait kinematics determined a priori based on their proposed effect on knee load (walking speed, toe-out angle, and lateral trunk lean angle). Approximately 50% of the variation in the first peak external knee adduction moment was explained by mechanical axis angle (25%), Western Ontario and McMaster Universities Osteoarthritis Index pain score (1%), gait speed (1%), toe-out angle (12%), and lateral trunk lean angle (13%). There was no confounding or interaction with Kellgren and Lawrence grade of severity. Gait kinematics, particularly lateral trunk lean, explain substantial variation in dynamic knee joint load in patients with medial compartment knee osteoarthritis. While largely ignored in previous gait studies, the effect of lateral trunk lean should be considered in future research evaluating risk factors and interventions for progression of knee osteoarthritis.
Article
Trunk lean motion on the frontal plane shifts the pressure across the medial-lateral cartilage of the stance limb's knee. The purpose of this study was to investigate trunk lean motion during walking in patients with knee osteoarthritis. The study involved five healthy normal controls and 12 patients with symptoms of knee osteoarthritis (six with unilateral and six with bilateral). The trunk lean angle and the direction during one stride cycle of walking were calculated using a three-dimensional gait analysis. There was no significant difference between the three groups (normal, unilateral knee OA, and bilateral knee OA group). However, patients with bilateral limb knee osteoarthritis displayed a tendency to lean their trunk toward the swing side. This study determined that bilateral OA patients exhibit the characteristic gait which may progress knee OA.
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