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Kinetic comparison of walking on a treadmill versus over ground in children with cerebral palsy
S84
ESMAC Abstracts 2015 / Gait & Posture 42S (2015) S1–S101
Fig. 1. Hip and knee angles for the three conditions averaged over all subjects.
ments of the subject. The gait profile score (GPS) [2] was calculated to see whether the overall gait pattern improved with FB. Results: Peak hip and knee extension angles improved significantly in both FBH and FBK (Fig. 1). In FBH, hip extension improved by 6.3 ± 6.7◦ (p = 0.01, 9/11 subjects) and knee extension tended to increase by 4.1 ± 7.1◦ (p < 0.1). In FBK, knee extension improved by 5.4 ± 5.1◦ (p < 0.01; 10/11 subjects) and hip extension by 2.8 ± 4.1◦ (p < 0.1). GPS did not change between conditions due to increased deviations elsewhere. These compensations differed between subjects and included increased trunk and pelvis motion, hip adduction and hip rotation. Discussion: Almost all children were flexible to some extent in their gait pattern and able to respond to real-time feedback, resulting in a significant and clinically relevant (>5◦ ) improvement in peak hip and knee extension. The variable compensation strategies used between patients may be indicative of different underlying causes of the crouch gait pattern. These findings show the potential of real-time feedback as a tool for advanced gait analysis and functional gait training in CP. References [1] van den Bogert A, et al. Med Biol Eng Comput 2013;51(10):1069–77. [2] Baker R, et al. Gait Posture 2009;30(3):265–9.
http://dx.doi.org/10.1016/j.gaitpost.2015.06.153
Fig. 1. (A) The between-stride variability in CP patients for walking in the different conditions. During SP, we found increased speed variability, that was predominant in the lower frequencies, corresponding to fluctuations over multiple strides. (B) The effect of SP versus FS walking on the knee angle for both patients with CP TD children. Interaction effects were found between SP and group (CP vs. TD), including for time to peak knee flexion during swing, but they were to small to be clinically relevant.
parameters were compared using a linear generalized estimating equation (GEE) analysis. Results: All children were able to walk in all conditions. Between-stride walking speed variability was twice as large during SP compared with FS (p < 0.001), fluctuating over multiple strides (Fig. 1A). There was no consistent effect of SP, but 5/33 parameters showed a small interaction effect between SP and group (e.g. increased stance percentage during SP in CP and decreased during SP in TD, effect size: 1.3%, p < 0.01; Fig. 1B). Walking with VR was rated higher than without VR (p = 0.018). There was no consistent main or interaction effect of VR. Discussion: In line with the adults [1], children walked with more walking speed fluctuations over multiple strides in SP, suggesting that SP allows for more natural stride variability. Small interaction effects were found between SP and group, suggesting that (some) children with CP needed more time to familiarize to SP walking, but these differences were too small to be relevant for clinical gait analysis. The VR environment was perceived as more resembling normal overground walking, as was found for the adults [1]. Since SP and VR did not consistently affect the kinematics and kinetics, both SP and FS walking, with and without a VR, can be used interchangeably for treadmill based clinical gait analysis. Reference
Session OS17 Feedback based Rehabilitation
[1] Sloot, et al. GaiPos 2014;39.
The effect of self-paced speed and virtual reality on treadmill gait in children with cerebral palsy
http://dx.doi.org/10.1016/j.gaitpost.2015.06.154
L. Sloot ∗ , M. van der Krogt, J. Harlaar Department of Rehabilitation Medicine, Research Institute MOVE, Amsterdam, Netherlands Research question: What is the effect of self-paced (SP) vs. fixed speed (FS) and with vs. without virtual reality (VR) on treadmill gait in typically developing (TD) and children with cerebral palsy (CP)? Introduction: Feedback-controlled treadmills along with an VR are increasingly used in clinical gait analysis. Adults have been shown to walk with more stride variability during SP and to perceive walking with VR as more comparable to overground walking, without clinically relevant differences in the gait pattern [1]. The effect of SP and VR are not yet examined in children and patient groups typically measured with clinical gait analysis. Materials and methods: Nine CP (11.6 ± 2.1 yr; GMFCS level I–II) and 11 TD children (10.6 ± 2.2 yr) walked on an instrumented treadmill with a speed-matched VR (GRAIL, Motekforce Link). After 6–10 min of habituation, subjects walked for 3 min in random order at SP and FS mode, both with and without VR. SP speed was based on the subject’s position and speed [1], FS on a baseline SP trial. 3D kinematics was collected using Vicon. Rated resemblance to overground walking and spatio-temporal, kinematic and kinetic
Session OS17 Feedback based Rehabilitation Kinetic comparison of walking on a treadmill versus over ground in children with cerebral palsy M. van der Krogt ∗ , L. Sloot, J. Harlaar Dept. Rehabilitation Medicine, VU University Medical Center, Research Institute MOVE, Amsterdam, Netherlands Research question: Are kinetic gait parameters comparable between over ground (OG) and treadmill (TM) walking in children with cerebral palsy (CP)? Introduction: Instrumented treadmills are increasingly used in clinical gait analysis and gait training, since they facilitate the measurement of consecutive steps and the use of feedback and perturbations. Recently it has been shown that kinematics are generally similar between OG and TM for typically developing (TD) children and children with CP [1]. However, the kinetics have not yet been compared for CP.
ESMAC Abstracts 2015 / Gait & Posture 42S (2015) S1–S101
S85
Session OS17 Feedback based Rehabilitation Positive effects of backward downhill treadmill training on spastic equinus gait M. Hösl ∗ , H. Böhm, J. Eck, L. Döderlein Orthopaedic Hospital for Children, Behandlungszentrum Aschau GmbH, Aschau i.Chiemgau, Germany
Fig. 1. Hip, knee, and ankle moments and powers averaged over all children with CP for OG (cyan) and TM (red).
Materials and methods: 9 CP (11.6 ± 2.1 y, GMFCS I–II) and 11 TD children (10.6 ± 2.2 y) walked in random order (1) OG in a conventional gait lab; and (2) on a dual-belt instrumented TM (R-Mill, Forcelink) with virtual reality screen, in self-paced mode [2]. 3D motion data were collected using identical systems in both labs (Optotrak, Northern Digital Inc.). Joint moments and powers were calculated using ISB definitions [3] and averaged over 5 strides for each lab. Condition (OG/TM), group (TD/CP) and interaction effects were determined using an ANOVA for repeated measures. Results: Walking speed did not differ significantly between OG and TM. Peak hip extension moment was increased in TM by 35% (p < 0.001, Fig. 1). Peak ankle extension moments were decreased by 7% in TD but increased by 9% in CP (interaction p = 0.039). Total net hip work tended to increase in TM (p = 0.09), while total net ankle work decreased from net neutral to a net dissipation of −0.07 J/kg (p < 0.001). Hip and knee abduction moments were 35% increased in TM (p < 0.01). Discussion: Kinetics differed considerably between TM and OG walking. A shift was observed from ankle to hip work, indicating that subjects relied more heavily on a hip strategy in TM. Hip extension moments were considerably larger in TM, which seemed the result of a 3◦ more forward lean of the trunk on the TM, possibly due to looking more downward. Similar increases in hip moments in TM were found previously for TD children [4]. The increased ankle moments in CP are consistent with previously found increases in ankle dorsiflexion angles [1]. The results show that kinetic data collected on a TM cannot be readily compared with OG data. Since both OG and TM are highly controlled settings, the question which setting is most relevant and useful for clinical treatment decision and evaluations remains open. References [1] [2] [3] [4]
Research question: Is backward downhill treadmill training [BDTT] a more effective stimulus than static manual stretch for improving calf function in spastic cerebral palsy (CP)? Introduction: Manual stretching is popular in CP but if patients functionally benefit is subject to controversy [1]. Recently, combined cyclic stretch and strengthening with robotics showed pos. effects on equinus gait [2]. In this regard, BDTT may induce repetitive dynamic stretch to the eccentrically contracting calf [3]. Thereby active ankle stiffness and calf stretch sensitivity may be modulated. Materials and methods: 10 participants with CP and equinus (age: 12.0 SD 4.2 y, GMFCS I/II) were included in a randomized crossover-study. All were allocated to static calf stretch (7 exercises) and to progressive (increased slope & belt speed) BDTT for 9 weeks (3× per week), intersected by a 5 week wash-out (no therapy). Before and after therapy, 3DGA was performed at comfortable (CWS) and at ‘fastest’ speed (FWS). Ankle and knee kinematics were captured and Gastrocnemius (GAS) muscle-tendon velocities calculated during swing as marker of dynamic spasticity [4]. Ankle stiffness was calculated as slope of PF moment-angle relationships. In addition, Timed Up and Go (TUG) and GMFM tests were done. Results: While CWS was not altered, FWS increased only with BDTT (Fig. 1). After stretching, ankle joint stiffness at CWS deteriorated. In contrast, after BDTT GAS lengthening velocities during swing phase were increased. Positive effects on GAS velocities were even more pronounced at FWS. Dorsiflexion and knee extension during stance or swing did however not show sign. changes with BDTT or stretching, at CWS or FWS. Still, GMFM Scores (Dim. D&E) and TUG time improved only after BDTT. Discussion: BDTT improved gait in particular at FWS while manual static stretch was ineffective. BDTT likely provides stretch and muscle contraction simultaneously [3]. Higher GAS lengthening velocities may indicate that after BDTT spastic stretch reflex thresholds went down and so faster walking speeds can be reached [4]. Walking down, or up inclines [5], seems to have pos. neuromuscular effects. BDTT also transfers to better ambulatory mobility
van der Krogt MM, et al. Gait Posture 2014;40(4):587–93. Sloot LH, et al. Gait Posture 2014;39(1):478–84. Cappozzo A, et al. Clin Biomech 1995;10(4):171–8. Rozumalski A, et al.ESMAC-SIAMOC. 2014.
http://dx.doi.org/10.1016/j.gaitpost.2015.06.155
Fig. 1. Results of 3DGA at fastest (FWS) and comfortable walking speed (CWS), as well as tests of functional ambulatory mobility.
ESMAC Abstracts 2015 / Gait & Posture 42S (2015) S1–S101
Fig. 1. Hip and knee angles for the three conditions averaged over all subjects.
ments of the subject. The gait profile score (GPS) [2] was calculated to see whether the overall gait pattern improved with FB. Results: Peak hip and knee extension angles improved significantly in both FBH and FBK (Fig. 1). In FBH, hip extension improved by 6.3 ± 6.7◦ (p = 0.01, 9/11 subjects) and knee extension tended to increase by 4.1 ± 7.1◦ (p < 0.1). In FBK, knee extension improved by 5.4 ± 5.1◦ (p < 0.01; 10/11 subjects) and hip extension by 2.8 ± 4.1◦ (p < 0.1). GPS did not change between conditions due to increased deviations elsewhere. These compensations differed between subjects and included increased trunk and pelvis motion, hip adduction and hip rotation. Discussion: Almost all children were flexible to some extent in their gait pattern and able to respond to real-time feedback, resulting in a significant and clinically relevant (>5◦ ) improvement in peak hip and knee extension. The variable compensation strategies used between patients may be indicative of different underlying causes of the crouch gait pattern. These findings show the potential of real-time feedback as a tool for advanced gait analysis and functional gait training in CP. References [1] van den Bogert A, et al. Med Biol Eng Comput 2013;51(10):1069–77. [2] Baker R, et al. Gait Posture 2009;30(3):265–9.
http://dx.doi.org/10.1016/j.gaitpost.2015.06.153
Fig. 1. (A) The between-stride variability in CP patients for walking in the different conditions. During SP, we found increased speed variability, that was predominant in the lower frequencies, corresponding to fluctuations over multiple strides. (B) The effect of SP versus FS walking on the knee angle for both patients with CP TD children. Interaction effects were found between SP and group (CP vs. TD), including for time to peak knee flexion during swing, but they were to small to be clinically relevant.
parameters were compared using a linear generalized estimating equation (GEE) analysis. Results: All children were able to walk in all conditions. Between-stride walking speed variability was twice as large during SP compared with FS (p < 0.001), fluctuating over multiple strides (Fig. 1A). There was no consistent effect of SP, but 5/33 parameters showed a small interaction effect between SP and group (e.g. increased stance percentage during SP in CP and decreased during SP in TD, effect size: 1.3%, p < 0.01; Fig. 1B). Walking with VR was rated higher than without VR (p = 0.018). There was no consistent main or interaction effect of VR. Discussion: In line with the adults [1], children walked with more walking speed fluctuations over multiple strides in SP, suggesting that SP allows for more natural stride variability. Small interaction effects were found between SP and group, suggesting that (some) children with CP needed more time to familiarize to SP walking, but these differences were too small to be relevant for clinical gait analysis. The VR environment was perceived as more resembling normal overground walking, as was found for the adults [1]. Since SP and VR did not consistently affect the kinematics and kinetics, both SP and FS walking, with and without a VR, can be used interchangeably for treadmill based clinical gait analysis. Reference
Session OS17 Feedback based Rehabilitation
[1] Sloot, et al. GaiPos 2014;39.
The effect of self-paced speed and virtual reality on treadmill gait in children with cerebral palsy
http://dx.doi.org/10.1016/j.gaitpost.2015.06.154
L. Sloot ∗ , M. van der Krogt, J. Harlaar Department of Rehabilitation Medicine, Research Institute MOVE, Amsterdam, Netherlands Research question: What is the effect of self-paced (SP) vs. fixed speed (FS) and with vs. without virtual reality (VR) on treadmill gait in typically developing (TD) and children with cerebral palsy (CP)? Introduction: Feedback-controlled treadmills along with an VR are increasingly used in clinical gait analysis. Adults have been shown to walk with more stride variability during SP and to perceive walking with VR as more comparable to overground walking, without clinically relevant differences in the gait pattern [1]. The effect of SP and VR are not yet examined in children and patient groups typically measured with clinical gait analysis. Materials and methods: Nine CP (11.6 ± 2.1 yr; GMFCS level I–II) and 11 TD children (10.6 ± 2.2 yr) walked on an instrumented treadmill with a speed-matched VR (GRAIL, Motekforce Link). After 6–10 min of habituation, subjects walked for 3 min in random order at SP and FS mode, both with and without VR. SP speed was based on the subject’s position and speed [1], FS on a baseline SP trial. 3D kinematics was collected using Vicon. Rated resemblance to overground walking and spatio-temporal, kinematic and kinetic
Session OS17 Feedback based Rehabilitation Kinetic comparison of walking on a treadmill versus over ground in children with cerebral palsy M. van der Krogt ∗ , L. Sloot, J. Harlaar Dept. Rehabilitation Medicine, VU University Medical Center, Research Institute MOVE, Amsterdam, Netherlands Research question: Are kinetic gait parameters comparable between over ground (OG) and treadmill (TM) walking in children with cerebral palsy (CP)? Introduction: Instrumented treadmills are increasingly used in clinical gait analysis and gait training, since they facilitate the measurement of consecutive steps and the use of feedback and perturbations. Recently it has been shown that kinematics are generally similar between OG and TM for typically developing (TD) children and children with CP [1]. However, the kinetics have not yet been compared for CP.
ESMAC Abstracts 2015 / Gait & Posture 42S (2015) S1–S101
S85
Session OS17 Feedback based Rehabilitation Positive effects of backward downhill treadmill training on spastic equinus gait M. Hösl ∗ , H. Böhm, J. Eck, L. Döderlein Orthopaedic Hospital for Children, Behandlungszentrum Aschau GmbH, Aschau i.Chiemgau, Germany
Fig. 1. Hip, knee, and ankle moments and powers averaged over all children with CP for OG (cyan) and TM (red).
Materials and methods: 9 CP (11.6 ± 2.1 y, GMFCS I–II) and 11 TD children (10.6 ± 2.2 y) walked in random order (1) OG in a conventional gait lab; and (2) on a dual-belt instrumented TM (R-Mill, Forcelink) with virtual reality screen, in self-paced mode [2]. 3D motion data were collected using identical systems in both labs (Optotrak, Northern Digital Inc.). Joint moments and powers were calculated using ISB definitions [3] and averaged over 5 strides for each lab. Condition (OG/TM), group (TD/CP) and interaction effects were determined using an ANOVA for repeated measures. Results: Walking speed did not differ significantly between OG and TM. Peak hip extension moment was increased in TM by 35% (p < 0.001, Fig. 1). Peak ankle extension moments were decreased by 7% in TD but increased by 9% in CP (interaction p = 0.039). Total net hip work tended to increase in TM (p = 0.09), while total net ankle work decreased from net neutral to a net dissipation of −0.07 J/kg (p < 0.001). Hip and knee abduction moments were 35% increased in TM (p < 0.01). Discussion: Kinetics differed considerably between TM and OG walking. A shift was observed from ankle to hip work, indicating that subjects relied more heavily on a hip strategy in TM. Hip extension moments were considerably larger in TM, which seemed the result of a 3◦ more forward lean of the trunk on the TM, possibly due to looking more downward. Similar increases in hip moments in TM were found previously for TD children [4]. The increased ankle moments in CP are consistent with previously found increases in ankle dorsiflexion angles [1]. The results show that kinetic data collected on a TM cannot be readily compared with OG data. Since both OG and TM are highly controlled settings, the question which setting is most relevant and useful for clinical treatment decision and evaluations remains open. References [1] [2] [3] [4]
Research question: Is backward downhill treadmill training [BDTT] a more effective stimulus than static manual stretch for improving calf function in spastic cerebral palsy (CP)? Introduction: Manual stretching is popular in CP but if patients functionally benefit is subject to controversy [1]. Recently, combined cyclic stretch and strengthening with robotics showed pos. effects on equinus gait [2]. In this regard, BDTT may induce repetitive dynamic stretch to the eccentrically contracting calf [3]. Thereby active ankle stiffness and calf stretch sensitivity may be modulated. Materials and methods: 10 participants with CP and equinus (age: 12.0 SD 4.2 y, GMFCS I/II) were included in a randomized crossover-study. All were allocated to static calf stretch (7 exercises) and to progressive (increased slope & belt speed) BDTT for 9 weeks (3× per week), intersected by a 5 week wash-out (no therapy). Before and after therapy, 3DGA was performed at comfortable (CWS) and at ‘fastest’ speed (FWS). Ankle and knee kinematics were captured and Gastrocnemius (GAS) muscle-tendon velocities calculated during swing as marker of dynamic spasticity [4]. Ankle stiffness was calculated as slope of PF moment-angle relationships. In addition, Timed Up and Go (TUG) and GMFM tests were done. Results: While CWS was not altered, FWS increased only with BDTT (Fig. 1). After stretching, ankle joint stiffness at CWS deteriorated. In contrast, after BDTT GAS lengthening velocities during swing phase were increased. Positive effects on GAS velocities were even more pronounced at FWS. Dorsiflexion and knee extension during stance or swing did however not show sign. changes with BDTT or stretching, at CWS or FWS. Still, GMFM Scores (Dim. D&E) and TUG time improved only after BDTT. Discussion: BDTT improved gait in particular at FWS while manual static stretch was ineffective. BDTT likely provides stretch and muscle contraction simultaneously [3]. Higher GAS lengthening velocities may indicate that after BDTT spastic stretch reflex thresholds went down and so faster walking speeds can be reached [4]. Walking down, or up inclines [5], seems to have pos. neuromuscular effects. BDTT also transfers to better ambulatory mobility
van der Krogt MM, et al. Gait Posture 2014;40(4):587–93. Sloot LH, et al. Gait Posture 2014;39(1):478–84. Cappozzo A, et al. Clin Biomech 1995;10(4):171–8. Rozumalski A, et al.ESMAC-SIAMOC. 2014.
http://dx.doi.org/10.1016/j.gaitpost.2015.06.155
Fig. 1. Results of 3DGA at fastest (FWS) and comfortable walking speed (CWS), as well as tests of functional ambulatory mobility.