- Email: [email protected]
Assessment of balance control while standing on a narrow beam
Track 3. Musculoskeletal systems and Performance-Joint ISB/ESB
kinematics after jump landing. Specific intervention programs trying to reduce knee injuries in female athletes appear necessary. References [1] Arendt. AJSM 1995. [2] Elias. MSSE 2001. [3] Ford. MSSE 2003. [4] Nyland. JOSPT 1994. [5] Wojtys. AJSM 1994. [6] McLean. JBE 2003.
7608 Mo-Tu, no. 33 (P58) Frequency spectrum analysis to measure balance performance J. Vanrenterghem, M. Lake, G. Barton, A. Lees. Liverpool John Moores University, Liverpool, UK It has been indicated that velocity rather than displacement of the centre of mass is associated with balance while standing upright (e.g. Hof, 2005, Journal of Biomechanics, 38, pp. 1-8). This suggests that from movement frequency one might find indications of balance performance. The purpose of this study was to test whether frequency spectrum analysis of centre of mass movement reveals information regarding balance performance during static and dynamic stability tests. The 13 subjects for this study were sedentary males (age = 60.4 ± 3.6 m, height = 1.75 ± 0.06 m, mass = 89.5 ± 11.0 kg). The Romberg test (eyes open/closed) was used as static stability test. As part of a random set of perturbations, two separate translations perturbed the subjects (eyes open, one period of cosine function at 1 Hz) in lateral direction (X) over 4 cm and antero-posterior direction (Y) over 8 cm. Movement was registered with 8 infrared cameras (Vicon) at 100 Hz using 39 markers on the body. Centre of mass position was calculated using raw marker positions, and filtered at 8 Hz. A spectral analysis between 0.1 and 10 Hz was performed. Paired samples t-test (p<0.05) and Pearson Correlation were used for statistical analysis. Results showed that mean frequency in eyes open and eyes closed conditions of the Romberg test was 0.31 ± 0.05 Hz and 0.31 ± 0.05 Hz (X), 0.28 ± 0.04 Hz and 0 . 2 8 ± 0 . 0 4 H z (Y). Eyes open vs closed were moderately correlated (r=0.525 and 0.317 for X and Y, respectively). Mean frequency of movement during the dynamic test was significantly higher at 0.79 ± 0 . 0 6 H z (X) and 0.82 ± 0 . 0 5 H z (Y). This correlated moderately with either of the Romberg conditions (r = 0.346 and 0.404) for the Y direction. Mean frequency correlated moderately with the Romberg eyes open condition for X direction (r=0.382), but not with the eyes closed condition (r=0.087). An overall larger inter-subject variability was found in the dynamic test compared to that in both Romberg conditions. As mean frequency and inter-subject variability were increased in the perturbed condition, frequency spectrum analysis of centre of mass movement might be a valuable instrument for measuring balance performance.
5231 Mo-Tu, no. 34 (P58) Assessment of balance control while standing on a narrow beam K. Gielo-Perczak, A. DiDomenico, R.W. McGorry, C.-C. Chang. Liberty Mutual Research Institute for Safety, Hopkinton, MA, USA An important task for falls-related accident prevention in the construction industry is to understand how workers perform tasks while standing on a structural beam. However, there are no specific safety recommendations to instruct workers on how to maintain balance on the beam. Beam width may be a critical parameter for stability control. The narrowest beam commonly used has a width of 10cm. The experiment was designed to investigate balance control on a slightly elevated and narrow beam during one-handed holding tasks. Twenty-five healthy men between 18 and 55 years old were recruited to participate in a half-day protocol. The study was conducted on ground level and at a height less than 7cm, with two beam widths (10 and 23cm) chosen from actual construction plans. The data collected on ground level was used as a control group. The participants stood on two aligned Kistler force platforms. The standing area on ground level was represented by a marked area with dimensions that matched the width of the beam being tested. Thirty seconds of data were collected at 100Hz. The variability of COP in the A/P and M/L directions, and variability of sway in the A/P and M/L directions within and between participants were identified. Postural sway measures increased when the participants were standing on the beams, but were smaller on the 10cm beam as compared to the 23cm beam. One-handed holding of a load (6.75 kg) decreased sway area and mean velocity. Further decreases in sway measures were associated with larger loads (11.25 kg). Altering the base of support by adjusting standing stride length did not have a significant effect on any of the sway measures (p > 0.05). This research may lead to a better understanding of workers' balance control as well as overall safety performance on narrow beams that may ultimately identify and reduce incidents of falling in construction environments.
$507 4676 Mo-Tu, no. 35 (P58) Biomechanical analysis of obstacle-crossing in patients with well-controlled diabetes M.-W. Liu 1,2, W.-C. Hsu 1, T.-W. Lu 1, H.-L. Chen 1, H.-C. Liu 1. 1Institute of Biomedical Engineering, National Taiwan University and NTUH, Taipei, Taiwan, 2 Taiwan Adventist Hospital, Taipei, Taiwan Introduction: Individuals with diabetes mellitus (DM) are 2.5-fold more likely to have accidental fall and fall-related injuries than normal. Tripping over obstacles was reported as a common cause of falls in the elderly. It is not clear whether DM patients would have increased difficulty in obstacles-negotiation. This study aimed to investigate the biomechanics of obstacle-crossing in DM for devising strategies to predict and prevent trip-related falls. Materials and Methods: Twelve DM patients and fifteen healthy adults walked and crossed obstacles of three heights (10, 20 and 30% of leg length) while kinematic and kinetic data were measured with a Vicon system (UK) and two forceplates (AMTI, USA). Toe clearances, horizontal distances, step lengths, step widths as well as lower limbs joint angles and moments were calculated and tested wih a mixed repeated measures analysis of variance for betweensubject and within-subject (obstacle height) effects (,J,=0.05). Results: No significant between-group differences were found in toe clearances and horizontal distances. When the leading toe was above the obstacle, the DM group had smaller trailing hip adduction with bigger plantarflexor moements and knee flexor moments (extensor moments in the control group). When the trailing toe was above the obstacle, the DM group abducted their swing hips while the normal group adducted theirs. The DM group had smaller leading hip adduction and knee flexor moments (extensor moments in the control group). The obstacle height effects on the toe clearances, hip crossing adductions and joint moments were similar between groups. Discussion and Conclusion: The two groups used different control strategies to achieve similar end-point trajectories, the group differences being in the frontal kinematics at the hip and saggital kinetics at the knee and ankle. The DM group used knee flexor and increased ankle plantarflexor moments possibly to control the forward movement of the body center of mass. If the demands on control and strength of these muscles are not met, risk of falls will increase in these patients.
7028 Mo-Tu, no. 36 (P58) Locomotor behaviour assessment in the rat by kinematic analysis J. Ilha 1, L.A. Peyr6-Tartaruga 1,2, R.T. Araujo 1, F. Metzen 2, T. Malysz 1, E Canto 2, M. Achaval Elena 1, J. Fagundes Loss 2. 1Laborat6rio de Histofisiologia Comparada, Programa de PSs-Gradua~&o em Neuroci~ncias, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil, 2 LaboratSrio de Pesquisa do exercicio, Programa de PSs-Gradua;&o em Ci~ncias do Movimento Humano, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil Clinical results of peripheral nerve repair demontrate loss of muscle function, impaired sensation and/or painful neuropathies. These modifications result likely in an different pattern of locomotion mechanics. Besides of traditional methods used in experimental animals as, electrophysiology and histomorphometry do not necessarily correlate with return of motor and sensory functions, walking track analysis have also recepted critics due to the difficult to obtain clear print marks owing to smearing of the print dragging of the tail. The aims of this study were develop an apparatus to continuously measure kinematics and to use these parameters in the assessment of gait in normal rats and following peripheral nerve crushing and repair. The testing apparatus was designed to measure angular and temporal parameters in a constant velocity on treadmill. Thirteen adults (three months-old) male Wistar rats were divided in control (n=5) and experimental (n=8) groups. Under anesthesia and sterile conditions the right sciatic nerve was crushed during 30 seconds. After 7 days, the rats were adapted on the treadmill during 4 days (walking 10min/session, once/day, at 5m.min-1). After this period the right hindlimb movement was videotaped (50hz) during treadmill walking at 8 m.min -1 on sagittal plane. The one-way repeated measures ANOVA was used for analyse the effects of lesion on kinematic and temporal parameters. The analysis showed that ducty factor and range of motion displayed significant differences (p < 0.05) between groups. The present results suggest that the angular and temporal parameters are the optimal parameters for evaluating recovery of useful function.
kinematics after jump landing. Specific intervention programs trying to reduce knee injuries in female athletes appear necessary. References [1] Arendt. AJSM 1995. [2] Elias. MSSE 2001. [3] Ford. MSSE 2003. [4] Nyland. JOSPT 1994. [5] Wojtys. AJSM 1994. [6] McLean. JBE 2003.
7608 Mo-Tu, no. 33 (P58) Frequency spectrum analysis to measure balance performance J. Vanrenterghem, M. Lake, G. Barton, A. Lees. Liverpool John Moores University, Liverpool, UK It has been indicated that velocity rather than displacement of the centre of mass is associated with balance while standing upright (e.g. Hof, 2005, Journal of Biomechanics, 38, pp. 1-8). This suggests that from movement frequency one might find indications of balance performance. The purpose of this study was to test whether frequency spectrum analysis of centre of mass movement reveals information regarding balance performance during static and dynamic stability tests. The 13 subjects for this study were sedentary males (age = 60.4 ± 3.6 m, height = 1.75 ± 0.06 m, mass = 89.5 ± 11.0 kg). The Romberg test (eyes open/closed) was used as static stability test. As part of a random set of perturbations, two separate translations perturbed the subjects (eyes open, one period of cosine function at 1 Hz) in lateral direction (X) over 4 cm and antero-posterior direction (Y) over 8 cm. Movement was registered with 8 infrared cameras (Vicon) at 100 Hz using 39 markers on the body. Centre of mass position was calculated using raw marker positions, and filtered at 8 Hz. A spectral analysis between 0.1 and 10 Hz was performed. Paired samples t-test (p<0.05) and Pearson Correlation were used for statistical analysis. Results showed that mean frequency in eyes open and eyes closed conditions of the Romberg test was 0.31 ± 0.05 Hz and 0.31 ± 0.05 Hz (X), 0.28 ± 0.04 Hz and 0 . 2 8 ± 0 . 0 4 H z (Y). Eyes open vs closed were moderately correlated (r=0.525 and 0.317 for X and Y, respectively). Mean frequency of movement during the dynamic test was significantly higher at 0.79 ± 0 . 0 6 H z (X) and 0.82 ± 0 . 0 5 H z (Y). This correlated moderately with either of the Romberg conditions (r = 0.346 and 0.404) for the Y direction. Mean frequency correlated moderately with the Romberg eyes open condition for X direction (r=0.382), but not with the eyes closed condition (r=0.087). An overall larger inter-subject variability was found in the dynamic test compared to that in both Romberg conditions. As mean frequency and inter-subject variability were increased in the perturbed condition, frequency spectrum analysis of centre of mass movement might be a valuable instrument for measuring balance performance.
5231 Mo-Tu, no. 34 (P58) Assessment of balance control while standing on a narrow beam K. Gielo-Perczak, A. DiDomenico, R.W. McGorry, C.-C. Chang. Liberty Mutual Research Institute for Safety, Hopkinton, MA, USA An important task for falls-related accident prevention in the construction industry is to understand how workers perform tasks while standing on a structural beam. However, there are no specific safety recommendations to instruct workers on how to maintain balance on the beam. Beam width may be a critical parameter for stability control. The narrowest beam commonly used has a width of 10cm. The experiment was designed to investigate balance control on a slightly elevated and narrow beam during one-handed holding tasks. Twenty-five healthy men between 18 and 55 years old were recruited to participate in a half-day protocol. The study was conducted on ground level and at a height less than 7cm, with two beam widths (10 and 23cm) chosen from actual construction plans. The data collected on ground level was used as a control group. The participants stood on two aligned Kistler force platforms. The standing area on ground level was represented by a marked area with dimensions that matched the width of the beam being tested. Thirty seconds of data were collected at 100Hz. The variability of COP in the A/P and M/L directions, and variability of sway in the A/P and M/L directions within and between participants were identified. Postural sway measures increased when the participants were standing on the beams, but were smaller on the 10cm beam as compared to the 23cm beam. One-handed holding of a load (6.75 kg) decreased sway area and mean velocity. Further decreases in sway measures were associated with larger loads (11.25 kg). Altering the base of support by adjusting standing stride length did not have a significant effect on any of the sway measures (p > 0.05). This research may lead to a better understanding of workers' balance control as well as overall safety performance on narrow beams that may ultimately identify and reduce incidents of falling in construction environments.
$507 4676 Mo-Tu, no. 35 (P58) Biomechanical analysis of obstacle-crossing in patients with well-controlled diabetes M.-W. Liu 1,2, W.-C. Hsu 1, T.-W. Lu 1, H.-L. Chen 1, H.-C. Liu 1. 1Institute of Biomedical Engineering, National Taiwan University and NTUH, Taipei, Taiwan, 2 Taiwan Adventist Hospital, Taipei, Taiwan Introduction: Individuals with diabetes mellitus (DM) are 2.5-fold more likely to have accidental fall and fall-related injuries than normal. Tripping over obstacles was reported as a common cause of falls in the elderly. It is not clear whether DM patients would have increased difficulty in obstacles-negotiation. This study aimed to investigate the biomechanics of obstacle-crossing in DM for devising strategies to predict and prevent trip-related falls. Materials and Methods: Twelve DM patients and fifteen healthy adults walked and crossed obstacles of three heights (10, 20 and 30% of leg length) while kinematic and kinetic data were measured with a Vicon system (UK) and two forceplates (AMTI, USA). Toe clearances, horizontal distances, step lengths, step widths as well as lower limbs joint angles and moments were calculated and tested wih a mixed repeated measures analysis of variance for betweensubject and within-subject (obstacle height) effects (,J,=0.05). Results: No significant between-group differences were found in toe clearances and horizontal distances. When the leading toe was above the obstacle, the DM group had smaller trailing hip adduction with bigger plantarflexor moements and knee flexor moments (extensor moments in the control group). When the trailing toe was above the obstacle, the DM group abducted their swing hips while the normal group adducted theirs. The DM group had smaller leading hip adduction and knee flexor moments (extensor moments in the control group). The obstacle height effects on the toe clearances, hip crossing adductions and joint moments were similar between groups. Discussion and Conclusion: The two groups used different control strategies to achieve similar end-point trajectories, the group differences being in the frontal kinematics at the hip and saggital kinetics at the knee and ankle. The DM group used knee flexor and increased ankle plantarflexor moments possibly to control the forward movement of the body center of mass. If the demands on control and strength of these muscles are not met, risk of falls will increase in these patients.
7028 Mo-Tu, no. 36 (P58) Locomotor behaviour assessment in the rat by kinematic analysis J. Ilha 1, L.A. Peyr6-Tartaruga 1,2, R.T. Araujo 1, F. Metzen 2, T. Malysz 1, E Canto 2, M. Achaval Elena 1, J. Fagundes Loss 2. 1Laborat6rio de Histofisiologia Comparada, Programa de PSs-Gradua~&o em Neuroci~ncias, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil, 2 LaboratSrio de Pesquisa do exercicio, Programa de PSs-Gradua;&o em Ci~ncias do Movimento Humano, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil Clinical results of peripheral nerve repair demontrate loss of muscle function, impaired sensation and/or painful neuropathies. These modifications result likely in an different pattern of locomotion mechanics. Besides of traditional methods used in experimental animals as, electrophysiology and histomorphometry do not necessarily correlate with return of motor and sensory functions, walking track analysis have also recepted critics due to the difficult to obtain clear print marks owing to smearing of the print dragging of the tail. The aims of this study were develop an apparatus to continuously measure kinematics and to use these parameters in the assessment of gait in normal rats and following peripheral nerve crushing and repair. The testing apparatus was designed to measure angular and temporal parameters in a constant velocity on treadmill. Thirteen adults (three months-old) male Wistar rats were divided in control (n=5) and experimental (n=8) groups. Under anesthesia and sterile conditions the right sciatic nerve was crushed during 30 seconds. After 7 days, the rats were adapted on the treadmill during 4 days (walking 10min/session, once/day, at 5m.min-1). After this period the right hindlimb movement was videotaped (50hz) during treadmill walking at 8 m.min -1 on sagittal plane. The one-way repeated measures ANOVA was used for analyse the effects of lesion on kinematic and temporal parameters. The analysis showed that ducty factor and range of motion displayed significant differences (p < 0.05) between groups. The present results suggest that the angular and temporal parameters are the optimal parameters for evaluating recovery of useful function.