Energy cost during walking in association with age and body height in children and young adults with cerebral palsy

AimThis cross-sectional study into children and young adults with cerebral palsy (CP) aimed to assess the association of gross energy cost (EC), net EC and net nondimensional (NN) EC during walking with age and body height, compared to typically developing (TD) peers.MethodData was collected in 128 participants with CP (mean age 11y9mo; GMFCS I,n = 48; II,n = 56; III, n = 24) and in 63 TD peers (mean age 12y5mo). Energy cost was assessed by measuring the oxygen consumption during over-ground walking at comfortable speed. Outcome measures derived from the assessment included the gross and net EC, and NN EC. Differences between the groups in the association between gross, net and NN EC with age and body height, were investigated with regression analyses and interaction effects (p < 0.05).ResultsInteraction effects for age and body height by group were not significant, indicating similar associations for gross, net and NN EC with age or body height among groups. The models showed a significant decline for gross, net and NN EC with increasing age per year (respectively −0.201 J kg⁻¹ m⁻¹; −0.073 J kg⁻¹ m⁻¹; −0.007) and body height per cm (respectively −0.057 J kg⁻¹ m⁻¹; −0.021 J kg⁻¹ m⁻¹; −0.002).InterpretationDespite higher gross and net EC values for CP compared to TD participants , similar declines in EC outcomes can be expected with growth for participants aged 4–22 years with CP. All energy cost outcomes showed a decline with growth, indicating that correcting for this decline is required when evaluating changes in gross EC, and, to a lesser extent, in net and NN EC in response to treatment or from natural course over time.     

Analysis of the relationships that body composition and muscular strength have with oxygen cost of walking in children with cerebral palsy

ObjectiveTo investigate whether body composition and lower extremity strength relate to oxygen cost of walking in children with cerebral palsy (CP), and to evaluate the relative contributions of these measures to explain variation in oxygen cost seen in this population.MethodsA total of 116 children with spastic diplegic CP, Gross Motor Function Classification System levels I–III, aged 8–18 participated. Strength, body composition (body mass index (BMI) and percent body fat) and oxygen cost were recorded. Pearson correlations assessed relationships between variables of body composition and strength to oxygen cost. Forward stepwise linear regression analyzed variance explained by strength and body composition measures. Oxygen data were analyzed by weight status classifications using one-way analysis of variance with significance set at p < 0.05.ResultsTotal strength (r = −0.27) and total extensor strength (r = −0.27) had fair inverse relationships with oxygen cost. Total extensor strength explained 7.5% (r² = 0.075, beta = −0.274, p < 0.01) of the variance in oxygen cost. Body composition did not explain significant variance in oxygen cost, however significant differences were found in oxygen consumption (p = 0.003) and walking velocity (p = 0.042) based on BMI weight classifications.ConclusionsFor ambulatory children with CP, oxygen cost during walking can be partially explained by total extensor strength and not body composition. However, those categorized as obese may adjust to a slower walking speed to keep their oxygen cost sustainable, which may further affect their ability to keep up with typically developing peers and possibly lead to greater fatigue.     

Analysis of the relationships that body composition and muscular strength have with oxygen cost of walking in children with cerebral palsy

ObjectiveTo investigate whether body composition and lower extremity strength relate to oxygen cost of walking in children with cerebral palsy (CP), and to evaluate the relative contributions of these measures to explain variation in oxygen cost seen in this population.MethodsA total of 116 children with spastic diplegic CP, Gross Motor Function Classification System levels I–III, aged 8–18 participated. Strength, body composition (body mass index (BMI) and percent body fat) and oxygen cost were recorded. Pearson correlations assessed relationships between variables of body composition and strength to oxygen cost. Forward stepwise linear regression analyzed variance explained by strength and body composition measures. Oxygen data were analyzed by weight status classifications using one-way analysis of variance with significance set at p < 0.05.ResultsTotal strength (r = −0.27) and total extensor strength (r = −0.27) had fair inverse relationships with oxygen cost. Total extensor strength explained 7.5% (r² = 0.075, beta = −0.274, p < 0.01) of the variance in oxygen cost. Body composition did not explain significant variance in oxygen cost, however significant differences were found in oxygen consumption (p = 0.003) and walking velocity (p = 0.042) based on BMI weight classifications.ConclusionsFor ambulatory children with CP, oxygen cost during walking can be partially explained by total extensor strength and not body composition. However, those categorized as obese may adjust to a slower walking speed to keep their oxygen cost sustainable, which may further affect their ability to keep up with typically developing peers and possibly lead to greater fatigue.     

Selective motor control correlates with gait abnormality in children with cerebral palsy

Children with bilateral cerebral palsy (CP) commonly have limited selective motor control (SMC). This affects their ability to complete functional tasks. The impact of impaired SMC on walking has yet to be fully understood. Measures of SMC have been shown to correlate with specific characteristics of gait, however the impact of SMC on overall gait pattern has not been reported. This study explored SMC data collected as part of routine gait analysis in children with bilateral CP.As part of their clinical assessment, SMC was measured with the Selective Control Assessment of the Lower Extremities (SCALE) in 194 patients with bilateral cerebral palsy attending for clinical gait analysis at a single centre. Their summed SCALE score was compared with overall gait impairment, as measured by Gait Profile Score (GPS).Score on SCALE showed a significant negative correlation with GPS (r_s = −0.603, p < 0.001). Cerebral injuries in CP result in damage to the motor tracts responsible for SMC. Our results indicate that this damage is also associated with changes in the development of walking pattern in children with CP.     

Further evidence of validity of the Gait Deviation Index

In this paper, the relationship of the Gait Deviation Index (GDI) to gross motor function and its ability to distinguish between different Gross Motor Function Classification System (GMFCS) levels was determined. A representative sample of 184 ambulant children with CP in GMFCS levels I (n = 57), II (n = 91), III (n = 22) and IV (n = 14) were recruited as part of a population-based study. Representative gait cycles were selected following a 3D gait analysis and gross motor function was assessed using the Gross Motor Function Measure (GMFM). GDI scores were calculated in Matlab. Valid 3D kinematic data were obtained for 173 participants and both kinematic and GMFM data were obtained for 150 participants. A substantial relationship between mean GDI and GMFM-66 scores was demonstrated (r = 0.70; p < 0.001) with significant differences in mean GDI scores between GMFCS levels (p < 0.001) indicating increasing levels of gait deviation in subjects less functionally able. The relationship between the GDI, GMFM and GMFCS in a representative sample of ambulators, lends further weight to the validity of the GDI scoring system. Furthermore it suggests that the subtleties of gait may not be wholly accounted for by gross motor function evaluation alone. Gait specific tools such as the GDI more likely capture both the functional and aesthetic components of walking.     

Biomechanical and perceived differences between overground and treadmill walking in children with cerebral palsy

The treadmill is widely used as an instrument for gait training and analysis. The primary purpose of this study was to compare biomechanical variables between overground and treadmill walking in children with cerebral palsy (CP). Perceived differences between the two walking modes were also investigated by comparing self-selected walking speeds. Twenty children with CP performed both overground and treadmill walking at a matched speed for biomechanical comparison using a 3-D motion analysis system. In addition, they were asked to select comfortable and fastest walking speeds under each walking condition to compare perceived differences. Significant differences in spatiotemporal variables were found including higher cadence and shorter stride length during treadmill walking at a matched speed (for all, P < .003). The comparison of joint kinematics demonstrated significant differences between overground and treadmill walking, which showed increases in peak angles of ankle dorsi-flexion, knee flexion/extension, and hip flexion (for all, P < .001), increases in ankle and hip excursions and a decrease in pelvic rotation excursion while walking on treadmill (for all, P < .002). Comparison of perceived difference revealed that children with CP chose significantly slower speeds when asked to select their comfortable and fastest walking speeds on the treadmill as compared to overground (for both, P < .001). Our results suggest that these biomechanical and perceived differences should be considered when using a treadmill for gait intervention or assessment.     

Energy cost of walking,symptomatic fatigue and perceived exertion in persons with multiple sclerosis

A higher energy cost of walking (Cw) is sometimes observed in MS, and could contribute to fatigue. The purpose of this study was to compare Cw at three speeds in MS and controls, and determine the effects of walking speed on fatigue and perceived exertion. We hypothesized that MS would have higher Cw, fatigue and exertion during walking than controls. Ten persons with MS and 14 controls of similar age and physical activity levels were studied. Oxygen consumption (VO₂) was obtained at rest and during treadmill walking at 0.6 and 1.4 m s⁻¹, and preferred speed. Cw was calculated as net VO₂:velocity. Fatigue and exertion were assessed using the visual analog fatigue and modified Borg scales, respectively. Preferred treadmill speed was not different between groups. Cw was higher in MS than controls across walking speeds (p = 0.003), with a group-by-speed interaction indicating higher Cw in MS at 0.6 m s⁻¹ (p = 0.001), but not at preferred speed or 1.4 m s⁻¹. MS reported greater fatigue (p = 0.001) and exertion (p = 0.004) at all speeds. Despite similar preferred speeds, and Cw at preferred and fast speeds, MS exhibited higher fatigue and exertion at all walking speeds. These results suggest that increased energy demands in MS are most notable at low speeds such as those used in everyday activities, which may contribute to fatigue over the day.     

The arm posture in children with unilateral Cerebral Palsy is mainly related to antero-posterior gait instability

In this observational case-control study we aimed to determine whether altered arm postures in children with unilateral CP (uniCP) are related to gait instability in a specific direction.Antero-posterior and medio-lateral Foot Placement Estimator instability measures and arm posture measures (vertical and antero-posterior hand position, sagittal and frontal upper arm elevation angle) were determined in eleven uniCP (7 years–10 months) and twenty-four typically developing children (9 years–6 months) at two walking speeds. Spearman-rank correlation analyses were made to examine the relationship between antero-posterior and medio-lateral arm posture and gait instability.Arm posture in both planes was related to antero-posterior instability (e.g. sagittal and frontal upper arm elevation angle correlated moderately with antero-posterior instability; R = 0.41, p < 0.001, R = −0.47, p < 0.001). In uniCP, increased antero-posterior instability was associated with a higher (R = −0.62, p = 0.002) and more frontal position of the hemiplegic hand (R = −0.58, p = 0.005), while the non-hemiplegic upper arm was rotated more backward (R = 0.63, p = 0.002) and both upper arms rotated more sideways (hemiplegic: R = −0.58, p = 0.004; non-hemiplegic: R = −0.55, p = 0.008).The altered non-hemiplegic (sagittal and frontal) arm posture in uniCP may be a compensation to reduce antero-posterior gait instability.     

Foot-related pain and disability and spatiotemporal parameters of gait during self-selected and fast walking speeds in people with gout: A two-arm cross sectional study

ObjectivesTo examine gait parameters in people with gout during different walking speeds while adjusting for body mass index (BMI) and foot-pain, and to determine the relationship between gait parameters and foot-pain and disability.MethodGait parameters were measured using the GAITRite™ walkway in 20 gout participants and 20 age- and sex-matched controls during self-selected and fast walking speeds. Foot-pain and disability was measured using the Manchester Foot Pain and Disability Index (MFPDI) which contains four domains relating to function, physical appearance, pain and work/leisure.ResultsAt the self-selected speed, gout participants demonstrated increased step time (p = 0.017), and stance time (p = 0.012), and reduced velocity (p = 0.031) and cadence (p = 0.013). At the fast speed, gout participants demonstrated increased step time (p = 0.007), swing time (p = 0.005) and stance time (p = 0.019) and reduced velocity (p = 0.036) and cadence (p = 0.009). For participants with gout, step length was correlated with total MFPDI (r = −0.62, p = 0.008), function (r = −0.65, p = 0.005) and physical appearance (r = −0.50, p = 0.041); stride length was correlated with total MFPDI (r = −0.62, p = 0.008), function (r = −0.65, p = 0.005) and physical appearance (r = −0.50, p = 0.041); and velocity was correlated with total MFPDI (r = −0.60, p = 0.011), function (r = −0.63, p = 0.007) and work/leisure (r = −0.53, p = 0.030).ConclusionGait patterns exhibited by people with gout are different from controls during both self-selected and fast walking speeds, even after adjusting for BMI and foot-pain. Additionally, gait parameters were strongly correlated with patient-reported functional limitation, physical appearance and work/leisure difficulties, while pain did not significantly influence gait in people with gout.     

Difference in the craniocaudal gradient of the maximum pixel value change rate between chronic obstructive pulmonary disease patients and normal subjects using sub-mGy dynamic chest radiography with a flat panel detector system

ObjectivesTo compare the craniocaudal gradients of the maximum pixel value change rate (MPCR) during tidal breathing between chronic obstructive pulmonary disease (COPD) patients and normal subjects using dynamic chest radiography.Materials and methodsThis prospective study was approved by the institutional review board and all participants provided written informed consent. Forty-three COPD patients (mean age, 71.6 ± 8.7 years) and 47 normal subjects (non-smoker healthy volunteers) (mean age, 54.8 ± 9.8 years) underwent sequential chest radiographs during tidal breathing in a standing position using dynamic chest radiography with a flat panel detector system. We evaluated the craniocaudal gradient of MPCR. The results were analyzed using an unpaired t-test and the Tukey–Kramer method.ResultsThe craniocaudal gradients of MPCR in COPD patients were significantly lower than those in normal subjects (right inspiratory phase, 75.5 ± 48.1 vs. 108.9 ± 42.0 s⁻¹ cm⁻¹, P < 0.001; right expiratory phase, 66.4 ± 40.6 vs. 89.8 ± 31.6 s⁻¹ cm⁻¹, P = 0.003; left inspiratory phase, 75.5 ± 48.2 vs. 108.2 ± 47.2 s⁻¹ cm⁻¹, P = 0.002; left expiratory phase, 60.9 ± 38.2 vs. 84.3 ± 29.5 s⁻¹ cm⁻¹, P = 0.002). No significant differences in height, weight, or BMI were observed between COPD and normal groups. In the sub-analysis, the gradients in severe COPD patients (global initiative for chronic obstructive lung disease [GOLD] 3 or 4, n = 26) were significantly lower than those in mild COPD patients (GOLD 1 or 2, n = 17) for both right and left inspiratory/expiratory phases (all P ≤ 0.005).ConclusionsA decrease of the craniocaudal gradient of MPCR was observed in COPD patients. The craniocaudal gradient was lower in severe COPD patients than in mild COPD patients.     

Timed limb coordination performance is associated with walking speed in healthy older adults: A cross-sectional exploratory study

Walking speed reflects quality of life, health status and physical function in older adults but interpreting measures of walking speed is affected by several confounders such as gender, age and height. Additionally, walking speed is influenced by neurologic conditions that impair limb coordination. In absence of defined pathology, it is less clear how varying levels of limb coordination influence walking speed. The purpose of this study was to examine the relationship between limb coordination and walking speed in older adults, controlling for effects of gender, age and height. Sixty-nine healthy, community-dwelling individuals over the age of 60 participated in the study. Participants completed a battery of timed upper and lower limb coordination tests. Normal and fast walking speed were measured over the inner six meters of a 10 m walkway. Correlation and regression analyses were used to examine the relationship between limb coordination performance and walking speed. Controlling for gender, age and height, variance in normal walking speed was accounted for by variance in pronation–supination performance (partial r = ?0.396, partial r² = 0.16) and variance in fast walking speed was accounted for by variance in finger-to-nose performance (partial r = ?0.356, partial r² = 0.13). The findings support our hypothesis that limb coordination performance would correlate with walking speed in healthy older adults. Moreover, limb coordination performance attenuated the effects of gender, age and height on walking speed. Limb coordination may be a modifiable determinant of walking speed in older adults.     

Mechanical efficiency and balance in adolescents and young adults with cerebral palsy

Mechanical efficiency (ME) during stair-climbing measures ambulation ability. This study investigated the relationship between ME and age, anthropometric, functional walking, and balance parameters in 52 adolescents with cerebral palsy (CP), age 13.5–23.3 yrs, who participated in an intervention study to improve walking. Measurements included ME, 6-min and 10-m walk tests and the Berg balance scale (BBS). Walk test measures correlated significantly with ME, as expected, as did BBS (r = 0.68) and age (r = 0.51). The multiple correlation coefficient with both age and BBS increased to 0.80. The measurements were divided into two groups of low (<40, n = 19) and high (>40, n = 33) BBS scores. Repeating regression analyses, demonstrated that in the low BBS group ME was significantly related to BBS, but not age, in contrast to opposite results in the high BBS group. Regressions were calculated for each of the 14 items of the BBS with ME. For the whole group, 12 items correlated significantly, but only three in the high BBS group (one leg standing, reach while standing and tandem standing). In the low BBS group 10 of the items correlated significantly, with the former three ranking near the top. Balance is an important component of ambulation in children with CP. Mobility in those scoring >40 is related to age, but in those more deficient in balance (<40) mobility is more closely associated with balance than age. Effective therapy to improve walking in younger children might incorporate more balance-focused exercises, similar to those related to BBS items strongly associated with ME.     

Kinematics of center of mass and center of pressure predict friction requirement at shoe–floor interface during walking

We aimed to determine whether inclination angles of the line connecting the whole body center of mass (COM) to the center of pressure (COP) (COM–COP angle) help predict the required coefficient of friction (RCOF) in young adult males during the weight acceptance and push-off phases in transient movements such as turning, gait termination and initiation, and steady-state movements such as straight walking. Seventeen healthy young adult males were asked to (1) walk in a straight line, (2) turn 60° with either foot (step and spin turns), and (3) initiate and terminate walking on a dry level floor. Peak absolute values of the ratio between resultant horizontal and vertical ground reaction forces during the weight acceptance and push-off phases (RCOF_h and RCOF_t, respectively) were calculated. COM–COP angles θ_h and θ_t at the instant of RCOF_h and RCOF_t, respectively, were also calculated. Bivariate regression analysis demonstrated that the |θ_h| and |θ_t| tangents were significant predictors of RCOF_h (R = 0.878; R² = 0.770; p < 0.001) and RCOF_t (R = 0.918; R² = 0.843; p < 0.001), respectively. The results suggest that COM and COP kinematics (i.e., the COM–COP angle) serve as a predictor of friction requirement during the weight acceptance and push-off phases in steady-state movements such as straight walking and transient movements such as turning as well as gait termination and initiation.     

Immediate effect of Masai Barefoot Technology shoes on knee joint moments in women with knee osteoarthritis

Footwear modification can beneficially alter knee loading in patients with knee osteoarthritis. This study evaluated the effect of Masai Barefoot Technology shoes on reductions in external knee moments in patients with knee osteoarthritis. Three-dimensional motion analysis was used to examine the effect of Masai Barefoot Technology versus control shoes on the knee adduction and flexion moments in 17 women (mean age, 63.6 years) with radiographically confirmed knee osteoarthritis. The lateral and anterior trunk lean values, knee flexion and adduction angles, and ground reaction force were also evaluated. The influence of the original walking pattern on the changes in knee moments with Masai Barefoot Technology shoes was evaluated. The knee flexion moment in early stance was significantly reduced while walking with the Masai Barefoot Technology shoes (0.25 ± 0.14 N m/kg m) as compared with walking with control shoes (0.30 ± 0.19 N m/kg m); whereas the knee adduction moment showed no changes. Masai Barefoot Technology shoes did not increase compensatory lateral and anterior trunk lean. The degree of knee flexion moment in the original walking pattern with control shoes was correlated directly with its reduction when wearing Masai Barefoot Technology shoes by multiple linear regression analysis (adjusted R² = 0.44, P < 0.01). Masai Barefoot Technology shoes reduced the knee flexion moment during walking without increasing the compensatory trunk lean and may therefore reduce external knee loading in women with knee osteoarthritis.     

Dietary supplementation with New Zealand blackcurrant extract enhances fat oxidation during submaximal exercise in the heat

ObjectivesThis study investigated the effect of 7 days’ supplementation with New Zealand blackcurrant extract on thermoregulation and substrate metabolism during running in the heat.DesignRandomized, double-blind, cross-over study.MethodsTwelve men and six women (mean ± SD: Age 27 ± 6 years, height 1.76 ± 0.10 m, mass 74 ± 12 kg, V̇O_2max 53.4 ± 7.0 mL kg⁻¹ min⁻¹) completed one assessment of maximal aerobic capacity and one familiarisation trial (18 °C, 40% relative humidity, RH), before ingesting 2 × 300 mg day⁻¹ capsules of CurraNZ™ (each containing 105 mg anthocyanin) or a visually matched placebo (2 × 300 mg microcrystalline cellulose M102) for 7 days (washout 14 days). On day 7 of each supplementation period, participants completed 60 min of fasted running at 65% V̇O_2max in hot ambient conditions (34 °C and 40% relative humidity).ResultsCarbohydrate oxidation was decreased in the NZBC trial [by 0.24 g min⁻¹ (95% CI: 0.21–0.27 g min^-1)] compared to placebo (p =  0.014, d = 0.46), and fat oxidation was increased in the NZBC trial [by 0.12 g min⁻¹ (95% CI: 0.10 to 0.15 g min⁻¹)], compared to placebo (p = 0.008, d = 0.57). NZBC did not influence heart rate (p = 0.963), rectal temperature (p = 0.380), skin temperature (p = 0.955), body temperature (p = 0.214) or physiological strain index (p = 0.705) during exercise.ConclusionsSeven-days intake of 600 mg NZBC extract increased fat oxidation without influencing cardiorespiratory or thermoregulatory variables during prolonged moderate intensity running in hot conditions.     

Mechanical work performed by the legs of children with spastic diplegic cerebral palsy

The purpose of this investigation was to evaluate the work performed on the center of mass by the legs of children with cerebral palsy. 10 children that were diagnosed as having cerebral palsy with spastic diplegia (Age = 9.1 ± 2 years), and 10 healthy children with no walking disabilities participated (Age = 9.4 ± 2 years). We collected individual leg ground reaction forces from four force platforms, and calculated the mechanical work performed on the center of mass by the lead and trail legs. The normalized walking speeds were not significantly (p = 0.33) different between the children with cerebral palsy (0.26 ± 0.07) and the controls (0.28 ± 0.06). The children with cerebral palsy performed significantly more negative work by the lead leg during double support (p = 0.0004), and significantly less positive work by the trail leg (p < 0.00001). During single support, the children with cerebral palsy performed significantly more positive work on the center of mass (p < 0.00001). No significant differences were found for the amount of negative work performed by the leg in single support (p = 0.84). Children with spastic diplegic cerebral palsy show a diminished ability to appropriately perform mechanical work by the legs to lift and redirect the center of mass. The altered mechanical work performed by the legs on the center of mass may play a role in the higher metabolic cost for walking noted in children with cerebral palsy.     

Sagittal spinopelvic alignment predicts hip function after total hip arthroplasty

The aim of this study was to investigate the association between preoperative sagittal spinopelvic alignment and postoperative clinical outcomes after total hip arthroplasty (THA). This retrospective study included 92 patients with hip osteoarthritis who underwent primary THA between May 2013 and October 2015. Patients’ characteristics, radiographic sagittal spinopelvic parameters and modified Harris Hip Scores, including function scores (gait scores and functional activities scores), were investigated. Multivariate linear regression analysis was performed to determine the associations between each preoperative sagittal spinopelvic parameter and postoperative hip function The preoperative sagittal spinopelvic parameters that were associated with postoperative gait scores were sagittal vertical axis (adjusted β-coefficient = − 0.28, P = 0.02), lumbar lordosis angle (adjusted β-coefficient = 0.29, P = 0.0089), pelvic tilt (adjusted β-coefficient = − 0.25, P = 0.045), sacral slope (adjusted β-coefficient = 0.27, P = 0.017) and pelvic incidence minus lumbar lordosis angle (adjusted β-coefficient = − 0.31, P = 0.01). The preoperative sagittal spinopelvic parameters that were related to the postoperative functional activities scores were sagittal vertical axis (adjusted β-coefficient = − 0.38, P = 0.0051) and pelvic incidence minus lumbar lordosis angle (adjusted β-coefficient = − 0.39, P = 0.0033). Patients with preoperative imbalanced sagittal alignment such as larger sagittal vertical axis, larger pelvic incidence minus lumbar lordosis and retroversion of pelvis had poorer clinical outcomes than others after THA. While, those preoperative imbalanced patients with anteversion of pelvis may have a compensatory ability which could correct the abnormal sagittal alignment after THA. Preoperative sagittal spinopelvic alignment affected postoperative clinical outcomes after THA.