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The effect of ankle foot orthoses on mechanical energy in children with cerebral palsy
Abstracts / Gait & Posture 30S (2009) S1–S153
collection was performed in a gait laboratory that was fitted with a figure of ‘8’ track of 34 m length and an in-house timing gate system. A Cosmed K4b2 , (Cosmed, Italy) was used to measure the respiratory parameters O2 and CO2 . One walking test was performed by each subject. The protocol commenced with a minimum of 5 min sitting to establish the subject’s baseline heart rate and oxygen consumption. This was followed by an 8 min walk at self-selected speed. Differences between the methods were examined using the paired Student’s t-test for a two-tailed test. Correlation between methods was assessed using the Pearson product moment (r) and agreement using a series of Bland & Altman plots. Significance was accepted at p ≤ 0.05. Results There was strong agreement between methods. Correlations were significant in both the unimpaired (r = 0.89) and in the children with CP (r = 0.91). T-tests revealed non-significance for between group comparisons. Discussion These results indicate that both methods could be used interchangeably to calculate non-dimensional net oxygen cost in our subjects. Data processing times were similar for both methods. References [1] Plasschaert, et al. Gait Posture 2009;29:311–6. [2] Schwartz M. Gait Posture 2007;26:494–500.
doi:10.1016/j.gaitpost.2009.08.105 O102 The effect of ankle foot orthoses on mechanical energy in children with cerebral palsy Patricia Van de Walle 1,2,3,∗ , Ann Hallemans 3,5 , Kim Christiaens 2 , Guy Molenaers 2,4 , Steven Truijen 3 , Irith Duden 3 , Lieve Demey 3 , Kaat Desloovere 1,2 1
Department of Rehabilitation Sciences, Katholieke Universiteit Leuven, Leuven, Belgium 2 Clinical Motion Analysis Laboratory of the University Hospital Pellenberg, Pellenberg, Belgium 3 Department of Health Sciences, University College Antwerp, Antwerp, Belgium 4 Department of Musculoskeletal Sciences, Katholieke Universiteit Leuven, Leuven, Belgium 5 Department of Biology, University of Antwerp, Antwerp, Belgium Summary/conclusions Although gait pattern improves in children with CP when walking with ankle foot orthoses (AFO), estimated mechanical energy (ME) becomes less efficient. Analysis of ME and movement of the centre of mass (CoM) should become part of clinical evaluation and research of AFO-use in children with CP.
S71
Introduction In the treatment of children with cerebral palsy AFOs are of great clinical use to correct deviations in disturbed gait patterns. Improved gait with AFOs is often at the expense of reduced ankle amplitude and power generation during third rocker (TR) and increased trunk movement [1,2]. Knowledge about the influence on ME is scarce. As AFO decreases TR, which has an important role in the reduction of the vertical CoM [3] the hypothesis was that CoM, external work (Wext) and recovery (R) would be less favourable with AFOs. Patients/materials and methods 24 children with hemiplegia and 17 children with diplegia who underwent gait analysis barefoot and with clinically prescribed AFO (type posterior leafspring) were retrospectively included in the study. Kinematic and kinetic data were collected using an eight camera VICONsystem (612) and two AMTI force plates. 36 clinically relevant gait parameters and Wext, R and vertical and lateral CoM (v CoM and 1 CoM) were calculated for two trials per subject and condition [4]. Differences between barefoot (BF) and AFO condition were determined by the Paired Sample T-test with Bonferroni correction per group of parameters. Results Cadence decreased, step length and walking velocity increased significantly with AFOs. Kinematics showed a significantly better ankle position at initial contact, during second rocker and in swing, better knee and hip kinematics and a significantly reduced TR amplitude of 11◦ with AFOs. Knee and hip kinetics improved, but ankle power generation during push off decreased with AFOs (p = 0.002). Wext increased (BF: 0.56 ± 0.20 J kg−1 m−1 , AFO: 0.73 ± 0.16 J kg−1 m−1 , p < 0.000), recovery decreased (BF: 44 ± 16%, AFO: 35 ± 12%, p = 0.005) and v CoM and 1 CoM increased from respectively 4.5 ± 1.0 cm and 2.2 ± 0.8 cm barefoot to 7.8 ± 1.7 cm and 2.8 ± 0.9 cm with AFOs (p < 0.000). v CoM correlated with TR amplitude (r = −0.424, p < 0.000) but not with Wext. To evaluate the influence of walking velocity parameters were plotted as a function of walking velocity for both situations (Fig. 1). Discussion The improvements in gait with AFO are comparable to those in literature. ME was less efficient with AFOs at all speeds. This decrease is partly explained by a decreased amplitude at TR, which confirms the importance of adequate TR on v CoM [3]. Another cause of increased ME with AFOs can probably be found in trunk movement which was found to increase with AFOs [2] and to be positively related to ME [5]. The increase of 1 CoM with AFOs supports this hypothesis, but further research should include trunk motion to be able to confirm. All the AFOs in this study were type posterior leafspring. Recent research indicates that a carbon fibre spring AFO has the same positive influence on gait pattern but with a lesser expense of TR and ankle power generation [1]. Its influence on mechanical energy should be part of future research.
Fig. 1. External work and the change in the vertical position of the centre of mass as a function of walking speed for barefoot (open circles) and AFO conditions (solid circles).
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Abstracts / Gait & Posture 30S (2009) S1–S153
Fig. 1. Summary of main results.
References [1] [2] [3] [4] [5]
Desloovere, et al. Gait Posture 2006;24(2):142–51. Molenaers, et al. Gait Posture 2006;24(S):174–5. Massaad, et al. Dev Med Child Neurol 2006;48(10):813–8. Cavagna. J Appl Physiol 1975;39(1):174–9. Van de Walle, et al. Gait Posture 2007;26(S1):5.
doi:10.1016/j.gaitpost.2009.08.106 O103 Characteristics of the energy cost of walking in children with cerebral palsy Frank Plasschaert ∗ , Kim Jones, Malcolm Forward Ghent Gait Laboratory, University Hospital Ghent, Ghent, Belgium Summary Energy cost of walking (ECOW) assessment is a valuable tool which can form an integral part of gait analysis in children with cerebral palsy. ECOW tests were carried out on a group of children with cerebral palsy (CP) and on an age, gender height and weight matched group of children with no known pathology in order to obtain comparative data characteristics for the two groups. Conclusions The non-dimensional net oxygen cost (NDNOC) of walking in the typical (GMFM 1-2) child with CP will be 112% higher than their unimpaired counterparts due to an 18% decrease in self-selected walking speed and a 36% increase in volume of inspired oxygen per unit mass (VO2 ). Introduction Whilst there is still discussion about the precise processing methods and protocols, there is now general acceptance of NDNOC as an objective measure of ECOW so long as a strict protocol is observed. On this basis, reference data may provide useful information for others planning to implement their own protocol. Patients/materials and methods We applied a published NDNOC data collection protocol that incorporated defined steady state methods [1] to 42 children with no known pathology and 42 children with cerebral palsy in order to calculate their NDNOC. The children’s ages ranged between 6 and 16 years (±2.6 years). Data collection was performed in a gait laboratory that was fitted with a figure of ‘8’ track of 34 m length and an in-house timing gate system. A Cosmed K4b2 , (Cosmed, Italy) was used to measure the respiratory parameters O2 and CO2 . One walking test was performed by each subject. The protocol commenced
with a minimum of 5 minutes sitting to establish the subject’s baseline heart rate and oxygen consumption. This was followed by an 8 minute walk at self-selected speed. Results See Fig. 1. Discussion There were no significant differences between the age, height, weight or BMI in our two groups and the within group differences with gender were negligible. On average, the CP patients, who had a range of severity of GMFM 1-2, walked slower but still used more oxygen than their unimpaired counterparts. Additionally, the NDNOC in the CP group was double that of the unimpaired controlled group. It is postulated that these differences are primarily due to biomechanical inefficiency. Reference [1] Plasschaert, et al. Gait Posture 2009;(29):311–6.
doi:10.1016/j.gaitpost.2009.08.107 O104 Metabolic cost of walking at different speeds in children with cerebral palsy Valeria Marconi 1,∗ , Davide Conte 1 , Paola Bonetti 2 , Alessandro Cosentino 2 , Barbara Montagnana 2 , Carlo Capelli 1 1 2
University of Verona, Verona, Italy Don Calabria Polifunctional Center, Verona, Italy
Summary We measured the energy cost of walking (C) and cardiac output (CO) in healthy children (H) and in children with cerebral palsy (CP) at sub-maximal speeds. C was then plotted as function of Froude number in order to consider the effect of the anthropometric features. Conclusions CO and C are larger in CP compared with H children, but this difference progressively reduces with increasing speed suggesting that therapeutic interventions should aim to increase children’s self-selected walking speed. Introduction CP children are prone to develop fatigue even during very moderate exercises as level walking during their daily physical activities.
collection was performed in a gait laboratory that was fitted with a figure of ‘8’ track of 34 m length and an in-house timing gate system. A Cosmed K4b2 , (Cosmed, Italy) was used to measure the respiratory parameters O2 and CO2 . One walking test was performed by each subject. The protocol commenced with a minimum of 5 min sitting to establish the subject’s baseline heart rate and oxygen consumption. This was followed by an 8 min walk at self-selected speed. Differences between the methods were examined using the paired Student’s t-test for a two-tailed test. Correlation between methods was assessed using the Pearson product moment (r) and agreement using a series of Bland & Altman plots. Significance was accepted at p ≤ 0.05. Results There was strong agreement between methods. Correlations were significant in both the unimpaired (r = 0.89) and in the children with CP (r = 0.91). T-tests revealed non-significance for between group comparisons. Discussion These results indicate that both methods could be used interchangeably to calculate non-dimensional net oxygen cost in our subjects. Data processing times were similar for both methods. References [1] Plasschaert, et al. Gait Posture 2009;29:311–6. [2] Schwartz M. Gait Posture 2007;26:494–500.
doi:10.1016/j.gaitpost.2009.08.105 O102 The effect of ankle foot orthoses on mechanical energy in children with cerebral palsy Patricia Van de Walle 1,2,3,∗ , Ann Hallemans 3,5 , Kim Christiaens 2 , Guy Molenaers 2,4 , Steven Truijen 3 , Irith Duden 3 , Lieve Demey 3 , Kaat Desloovere 1,2 1
Department of Rehabilitation Sciences, Katholieke Universiteit Leuven, Leuven, Belgium 2 Clinical Motion Analysis Laboratory of the University Hospital Pellenberg, Pellenberg, Belgium 3 Department of Health Sciences, University College Antwerp, Antwerp, Belgium 4 Department of Musculoskeletal Sciences, Katholieke Universiteit Leuven, Leuven, Belgium 5 Department of Biology, University of Antwerp, Antwerp, Belgium Summary/conclusions Although gait pattern improves in children with CP when walking with ankle foot orthoses (AFO), estimated mechanical energy (ME) becomes less efficient. Analysis of ME and movement of the centre of mass (CoM) should become part of clinical evaluation and research of AFO-use in children with CP.
S71
Introduction In the treatment of children with cerebral palsy AFOs are of great clinical use to correct deviations in disturbed gait patterns. Improved gait with AFOs is often at the expense of reduced ankle amplitude and power generation during third rocker (TR) and increased trunk movement [1,2]. Knowledge about the influence on ME is scarce. As AFO decreases TR, which has an important role in the reduction of the vertical CoM [3] the hypothesis was that CoM, external work (Wext) and recovery (R) would be less favourable with AFOs. Patients/materials and methods 24 children with hemiplegia and 17 children with diplegia who underwent gait analysis barefoot and with clinically prescribed AFO (type posterior leafspring) were retrospectively included in the study. Kinematic and kinetic data were collected using an eight camera VICONsystem (612) and two AMTI force plates. 36 clinically relevant gait parameters and Wext, R and vertical and lateral CoM (v CoM and 1 CoM) were calculated for two trials per subject and condition [4]. Differences between barefoot (BF) and AFO condition were determined by the Paired Sample T-test with Bonferroni correction per group of parameters. Results Cadence decreased, step length and walking velocity increased significantly with AFOs. Kinematics showed a significantly better ankle position at initial contact, during second rocker and in swing, better knee and hip kinematics and a significantly reduced TR amplitude of 11◦ with AFOs. Knee and hip kinetics improved, but ankle power generation during push off decreased with AFOs (p = 0.002). Wext increased (BF: 0.56 ± 0.20 J kg−1 m−1 , AFO: 0.73 ± 0.16 J kg−1 m−1 , p < 0.000), recovery decreased (BF: 44 ± 16%, AFO: 35 ± 12%, p = 0.005) and v CoM and 1 CoM increased from respectively 4.5 ± 1.0 cm and 2.2 ± 0.8 cm barefoot to 7.8 ± 1.7 cm and 2.8 ± 0.9 cm with AFOs (p < 0.000). v CoM correlated with TR amplitude (r = −0.424, p < 0.000) but not with Wext. To evaluate the influence of walking velocity parameters were plotted as a function of walking velocity for both situations (Fig. 1). Discussion The improvements in gait with AFO are comparable to those in literature. ME was less efficient with AFOs at all speeds. This decrease is partly explained by a decreased amplitude at TR, which confirms the importance of adequate TR on v CoM [3]. Another cause of increased ME with AFOs can probably be found in trunk movement which was found to increase with AFOs [2] and to be positively related to ME [5]. The increase of 1 CoM with AFOs supports this hypothesis, but further research should include trunk motion to be able to confirm. All the AFOs in this study were type posterior leafspring. Recent research indicates that a carbon fibre spring AFO has the same positive influence on gait pattern but with a lesser expense of TR and ankle power generation [1]. Its influence on mechanical energy should be part of future research.
Fig. 1. External work and the change in the vertical position of the centre of mass as a function of walking speed for barefoot (open circles) and AFO conditions (solid circles).
S72
Abstracts / Gait & Posture 30S (2009) S1–S153
Fig. 1. Summary of main results.
References [1] [2] [3] [4] [5]
Desloovere, et al. Gait Posture 2006;24(2):142–51. Molenaers, et al. Gait Posture 2006;24(S):174–5. Massaad, et al. Dev Med Child Neurol 2006;48(10):813–8. Cavagna. J Appl Physiol 1975;39(1):174–9. Van de Walle, et al. Gait Posture 2007;26(S1):5.
doi:10.1016/j.gaitpost.2009.08.106 O103 Characteristics of the energy cost of walking in children with cerebral palsy Frank Plasschaert ∗ , Kim Jones, Malcolm Forward Ghent Gait Laboratory, University Hospital Ghent, Ghent, Belgium Summary Energy cost of walking (ECOW) assessment is a valuable tool which can form an integral part of gait analysis in children with cerebral palsy. ECOW tests were carried out on a group of children with cerebral palsy (CP) and on an age, gender height and weight matched group of children with no known pathology in order to obtain comparative data characteristics for the two groups. Conclusions The non-dimensional net oxygen cost (NDNOC) of walking in the typical (GMFM 1-2) child with CP will be 112% higher than their unimpaired counterparts due to an 18% decrease in self-selected walking speed and a 36% increase in volume of inspired oxygen per unit mass (VO2 ). Introduction Whilst there is still discussion about the precise processing methods and protocols, there is now general acceptance of NDNOC as an objective measure of ECOW so long as a strict protocol is observed. On this basis, reference data may provide useful information for others planning to implement their own protocol. Patients/materials and methods We applied a published NDNOC data collection protocol that incorporated defined steady state methods [1] to 42 children with no known pathology and 42 children with cerebral palsy in order to calculate their NDNOC. The children’s ages ranged between 6 and 16 years (±2.6 years). Data collection was performed in a gait laboratory that was fitted with a figure of ‘8’ track of 34 m length and an in-house timing gate system. A Cosmed K4b2 , (Cosmed, Italy) was used to measure the respiratory parameters O2 and CO2 . One walking test was performed by each subject. The protocol commenced
with a minimum of 5 minutes sitting to establish the subject’s baseline heart rate and oxygen consumption. This was followed by an 8 minute walk at self-selected speed. Results See Fig. 1. Discussion There were no significant differences between the age, height, weight or BMI in our two groups and the within group differences with gender were negligible. On average, the CP patients, who had a range of severity of GMFM 1-2, walked slower but still used more oxygen than their unimpaired counterparts. Additionally, the NDNOC in the CP group was double that of the unimpaired controlled group. It is postulated that these differences are primarily due to biomechanical inefficiency. Reference [1] Plasschaert, et al. Gait Posture 2009;(29):311–6.
doi:10.1016/j.gaitpost.2009.08.107 O104 Metabolic cost of walking at different speeds in children with cerebral palsy Valeria Marconi 1,∗ , Davide Conte 1 , Paola Bonetti 2 , Alessandro Cosentino 2 , Barbara Montagnana 2 , Carlo Capelli 1 1 2
University of Verona, Verona, Italy Don Calabria Polifunctional Center, Verona, Italy
Summary We measured the energy cost of walking (C) and cardiac output (CO) in healthy children (H) and in children with cerebral palsy (CP) at sub-maximal speeds. C was then plotted as function of Froude number in order to consider the effect of the anthropometric features. Conclusions CO and C are larger in CP compared with H children, but this difference progressively reduces with increasing speed suggesting that therapeutic interventions should aim to increase children’s self-selected walking speed. Introduction CP children are prone to develop fatigue even during very moderate exercises as level walking during their daily physical activities.