Body Mass Index is Related to Femoral Anteversion, Hip Rotation During Gait, and Passive Hip Range of Motion in Children and Adolescents.

BACKGROUND: Overweight and obesity are major global health issues, often linked to orthopaedic problems, skeletal malalignments, and altered gait biomechanics. However, skeletal and biomechanical adaptions in the transverse plane remain underexplored. Therefore, this study aimed to investigate the relationship between body mass index (BMI) and variables describing lower extremity torsional profiles, hip rotation mobility, and transverse plane gait characteristics in children and adolescents. METHODS: Acetabular and femoral anteversion, tibial torsion (measured through computed tomography), hip and knee rotation, and foot progression angles during the stance phase of gait (measured by 3D gait analysis), as well as passive hip rotation range of motion (evaluated as the midpoint of hip rotation in clinical examination), were retrospectively analyzed in 122 children and adolescents. Correlations between all variables and logit-transformed BMI percentiles were calculated. RESULTS: Moderate correlations were found between BMI percentile and hip rotation during the stance phase (r=-0.68, P<0.001), the passive midpoint of hip rotation (r=-0.51, P<0.001), and femoral anteversion (r=-0.50, P<0.001). Small correlations were observed for acetabular anteversion (r=-0.36, P<0.001), knee rotation during stance phase (r=0.34, P<0.001), and foot progression angle during stance phase (r=-0.31, P<0.001). Tibial torsion showed a nonsignificant negligible relationship with BMI percentile (r=-0.26, P=0.004). CONCLUSION: BMI percentile was positively correlated with external hip rotation during the stance phase of gait and passive external hip rotation, and negatively correlated with femoral anteversion. These findings suggest abnormal body weight is associated with static and dynamic biomechanical alterations. Therefore, weight management should be considered in orthopaedic assessments and treatment planning for children and adolescents.

Efficacy of hinged and carbon fiber ankle-foot orthoses in children with unilateral spastic cerebral palsy and drop-foot gait pattern.

BACKGROUND: In children with unilateral spastic cerebral palsy (USCP), ankle-foot orthoses (AFOs) are widely used to correct common gait deviations such as a drop-foot pattern. Most studies on this topic have investigated specific time points while omitting other parts of the gait cycle. OBJECTIVES: This study investigated the separate effects of prefabricated carbon fiber AFOs and custom-made hinged AFOs compared with barefoot walking in children with USCP with a drop-foot gait pattern using statistical parametric mapping. STUDY DESIGN: Retrospective, cross-sectional, repeated measures study. METHODS: Twenty ambulatory children (9.9 ± 2.5 years) with USCP and a drop-foot gait pattern were included. Kinematics, kinetics, and spatiotemporal parameters assessed during 3-dimensional gait analysis were compared between barefoot and AFO walking. Statistical parametric mapping was used to compare joint angles and moment waveforms. Kinematics, kinetics and spatiotemporal parameters assessed during 3-dimensional gait analysis were compared between barefoot and AFO walking for each AFO type but not between the 2 AFO types. RESULTS: Compared with barefoot walking, there was a steeper sole angle at initial contact, corresponding to a heel strike pattern, and an increased ankle dorsiflexion in swing with the use of both AFOs. The ankle plantar flexion moment during loading response increased. Ankle power generation during pre-swing decreased in the carbon fiber AFO group when walking with AFOs. CONCLUSIONS: Both AFOs were beneficial for improving a drop-foot gait pattern in these small patient groups and can, therefore, be recommended to treat this gait deviation in patients with unilateral cerebral palsy. However, the reduction in ankle power generation during push-off and additional goals targeted by AFOs, such as correction of structural or flexible foot deformities, should be considered for prescription.

Effects of ankle-foot orthoses on different gait patterns in children with spastic cerebral palsy: A statistical parametric mapping study.

BACKGROUND: Ankle-foot orthoses (AFOs) are a common treatment to correct gait deviations in children with spastic cerebral palsy (SCP). Studies on the outcome of AFOs on gait often do not account for different gait patterns. OBJECTIVES: The aim of this study was to investigate the effects of AFOs on specific gait patterns in children with cerebral palsy. STUDY DESIGN: Retrospective, unblinded, controlled, cross-over study. METHODS: Twenty-seven children with SCP were assessed in the conditions walking barefoot or with shoes and AFO. AFOs were prescribed based on usual clinical practice. Gait patterns for each leg were classified as excess ankle plantarflexion in stance (equinus), excess knee extension in stance (hyperextension), or excess knee flexion in stance (crouch). Differences in spatial-temporal variables and sagittal kinematics and kinetics of the hip, knee, and ankle between the 2 conditions were determined using paired t-tests and statistical parametric mapping, respectively. The effect of AFO-footwear neutral angle on knee flexion was tested using statistical parametric mapping regression. RESULTS: AFO use improved spatial-temporal variables and reduced ankle power generation in preswing. For "equinus" and "hyperextension" gait patterns, AFOs decreased ankle plantarflexion in preswing and initial swing and decreased ankle power in preswing. Ankle dorsiflexion moment increased in all gait pattern groups. Knee and hip variables did not change in any of the 3 groups. AFO-footwear neutral angle had no effect on changes in sagittal knee angle. CONCLUSION: Although improvements in spatial-temporal variables were seen, gait deviations could only partially be corrected. Therefore, AFO prescriptions and design should individually address specific gait deviations and their effectiveness in children with SCP should be controlled.

Association of HbA1c with VO2max in Individuals with Type 1 Diabetes: A Systematic Review and Meta-Analysis.

The aim of this systematic review and meta-analysis was to evaluate the association between glycemic control (HbA1c) and functional capacity (VO2max) in individuals with type 1 diabetes (T1DM). A systematic literature search was conducted in EMBASE, PubMed, Cochrane Central Register of Controlled Trials, and ISI Web of Knowledge for publications from January 1950 until July 2020. Randomized and observational controlled trials with a minimum number of three participants were included if cardio-pulmonary exercise tests to determine VO2max and HbA1c measurement has been performed. Pooled mean values were estimated for VO2max and HbA1c and weighted Pearson correlation and meta-regression were performed to assess the association between these parameters. We included 187 studies with a total of 3278 individuals with T1DM. The pooled mean HbA1c value was 8.1% (95%CI; 7.9−8.3%), and relative VO2max was 38.5 mL/min/kg (37.3−39.6). The pooled mean VO2max was significantly lower (36.9 vs. 40.7, p = 0.001) in studies reporting a mean HbA1c > 7.5% compared to studies with a mean HbA1c ≤ 7.5%. Weighted Pearson correlation coefficient was r = −0.19 (p < 0.001) between VO2max and HbA1c. Meta-regression adjusted for age and sex showed a significant decrease of −0.94 mL/min/kg in VO2max per HbA1c increase of 1% (p = 0.024). In conclusion, we were able to determine a statistically significant correlation between HbA1c and VO2max in individuals with T1DM. However, as the correlation was only weak, the association of HbA1c and VO2max might not be of clinical relevance in individuals with T1DM.

Physiological Responses and Performance During a 3-Minute Cycle Time Trial: Standard Paced Versus All-Out Paced.

PURPOSE: To compare performance and physiological responses between a standard-paced 3-minute time trial (TTSP, ie, pacing based on normal intention) and a consistently all-out-paced 3-minute time trial (TTAOP). METHODS: Sixteen well-trained male cyclists completed the TTSP and TTAOP, on separate days of testing, on a cycling ergometer with power output and respiratory variables measured. Time trials were preceded by 7 × 4-minute submaximal stages of increasing intensity with the linear relationship between power output and metabolic rate used to estimate the contribution from aerobic and anaerobic energy resources. The time course of anaerobic and aerobic contributions to power output was analyzed using statistical parametric mapping. RESULTS: Mean power output was not different between the 2 pacing strategies (TTSP = 417 [43] W, TTAOP = 423 [41] W; P = 0.158). TTAOP resulted in higher peak power output (P < .001), mean ventilation rate (P < .001), mean heart rate (P = .044), peak accumulated anaerobically attributable work (P = .026), post-time-trial blood lactate concentration (P = .035), and rating of perceived exertion (P = .036). Statistical parametric mapping revealed a higher anaerobic contribution to power output during the first ∼30 seconds and a lower contribution between ∼90 and 170 seconds for TTAOP than TTSP. The aerobic contribution to power output was higher between ∼55 and 75 seconds for TTAOP. CONCLUSIONS: Although there was no significant difference in performance (ie, mean power output) between the 2 pacing strategies, differences were found in the distribution of anaerobically and aerobically attributable power output. This implies that athletes can pace a 3-minute maximal effort very differently but achieve the same result.

Intra-rater reliability of leg blood flow during dynamic exercise using Doppler ultrasound.

Developing an exercise model that resembles a traditional form of aerobic exercise and facilitates a complete simultaneous assessment of multiple parameters within the oxygen cascade is critically for understanding exercise intolerances in diseased populations. Measurement of muscle blood flow is a crucial component of such a model and previous studies have used invasive procedures to determine blood flow kinetics; however, this may not be appropriate in certain populations. Furthermore, current models utilizing Doppler ultrasound use isolated limb exercise and while these studies have provided useful data, the exercise model does not mimic the whole-body physiological response to continuous dynamic exercise. Therefore, we aimed to measure common femoral artery blood flow using Doppler ultrasound during continuous dynamic stepping exercise performed at three independent workloads to assess the within day and between-day reliability for such an exercise modality. We report a within-session coefficient of variation of 5.8% from three combined workloads and a between-day coefficient of variation of 12.7%. These values demonstrate acceptable measurement accuracy and support our intention of utilizing this noninvasive exercise model for an integrative assessment of the whole-body physiological response to exercise in a range of populations.

Does pathologically increased or decreased tibial torsion affect muscle activations during walking in typically developing adolescents?

A reduced capacity of plantar flexors and other muscles to extend the hip and knee during gait was shown in modelling studies when the tibial torsion angle is > 30° than normal. The aim of the current study was to determine if patients with increased or decreased tibial torsion show deviating muscle activations in knee and hip extensors in surface electromyography (EMG). Patients with CT confirmed increased tibial torsion (n = 19, ITT), decreased tibial torsion (n = 21, DTT) and age-matched healthy controls (n = 20) were included in this retrospective study. Additionally, kinematic and kinetic data were recorded during three-dimensional gait analysis. Surface EMG was recorded for vastus medialis and medial hamstrings. Statistical parametric mapping with a one-way ANOVA and post-hoc Bonferroni corrected two-sample t-tests were used to obtain differences in joint angles and moments. ITT and DTT showed an increased and decreased external foot progression angle, respectively. No additional muscle activations in vastus medialis and medial hamstrings were found in both patient groups compared to controls. DTT showed an increased hip flexion through parts of the gait cycle and both patient groups had a decreased knee extension moment in terminal stance. Our hypothesis of deviating muscle activation had to be rejected. It could be that in most orthopaedic patients the amount of exceeding tibial torsion is too low to cause substantial deviations in gait and muscle activation patterns.