Abstract
Background and purpose:
Erect posture had been advocated to offer better protection of spine health among various standing postures. This study aimed at comparing the effectiveness of postural adjustments in response to expected and unexpected perturbations between erect posture, swayback and hyperlordotic postures.
Methods:
Forty-seven healthy adults received a top-down perturbation generated by a load of 1.5% body weight under eyes-closed and eyes-open conditions in erect, hyperlordotic, and swayback postures. Joint angle onsets and centre of pressure parameters were used to evaluate postural adjustments. Muscle onsets and co-contraction indexes between paired muscles (0-100%) were assessed. Two-way repeated measures analysis of variance was used to compare the listed parameters for between-condition, between-posture and condition-and-posture interaction. Post-hoc paired sample t-test with Bonferroni correction was performed if significant difference condition-and-posture interactions were found.
Results:
Centre of pressure (COP) path length, ellipse area and average velocity were greater in eyes-closed as compared to eyes-open conditions (p<0.001). Significant between-posture difference was detected in COP path length (p<0.035), pelvic tilt onset (p<0.038) and all co-contraction indexes (p<0.001). Post-hoc analysis revealed greater COP path length in swayback posture comparing to erect (p=0.007) and hyperlordotic postures (p=0.009) under eyes-closed conditions. Significantly greater co-contraction indexes were found in hyperlordotic posture as compared to erect and swayback postures (p<0.05).
Conclusion:
Hyperlordotic and swayback postures compromised the effectiveness of the active and passive subsystems of spinal stability. Such neuromuscular deficits may increase the risk of spinal disorders development by lessening the capacity of the spine to withstand loading and shear forces.
Erect posture had been advocated to offer better protection of spine health among various standing postures. This study aimed at comparing the effectiveness of postural adjustments in response to expected and unexpected perturbations between erect posture, swayback and hyperlordotic postures.
Methods:
Forty-seven healthy adults received a top-down perturbation generated by a load of 1.5% body weight under eyes-closed and eyes-open conditions in erect, hyperlordotic, and swayback postures. Joint angle onsets and centre of pressure parameters were used to evaluate postural adjustments. Muscle onsets and co-contraction indexes between paired muscles (0-100%) were assessed. Two-way repeated measures analysis of variance was used to compare the listed parameters for between-condition, between-posture and condition-and-posture interaction. Post-hoc paired sample t-test with Bonferroni correction was performed if significant difference condition-and-posture interactions were found.
Results:
Centre of pressure (COP) path length, ellipse area and average velocity were greater in eyes-closed as compared to eyes-open conditions (p<0.001). Significant between-posture difference was detected in COP path length (p<0.035), pelvic tilt onset (p<0.038) and all co-contraction indexes (p<0.001). Post-hoc analysis revealed greater COP path length in swayback posture comparing to erect (p=0.007) and hyperlordotic postures (p=0.009) under eyes-closed conditions. Significantly greater co-contraction indexes were found in hyperlordotic posture as compared to erect and swayback postures (p<0.05).
Conclusion:
Hyperlordotic and swayback postures compromised the effectiveness of the active and passive subsystems of spinal stability. Such neuromuscular deficits may increase the risk of spinal disorders development by lessening the capacity of the spine to withstand loading and shear forces.
| Original language | English |
|---|---|
| Publication status | Published - 24 Jun 2023 |
| Event | The Hong Kong Physiotherapy Association 60th Anniversary Conference - Nina Hotel Tsuen Wan West, Hong Kong, Hong Kong Duration: 23 Jun 2023 → 25 Jun 2023 |
Conference
| Conference | The Hong Kong Physiotherapy Association 60th Anniversary Conference |
|---|---|
| Country/Territory | Hong Kong |
| City | Hong Kong |
| Period | 23/06/23 → 25/06/23 |
Fingerprint
Dive into the research topics of 'Reactive postural adjustment in response to sudden perturbation in health adults: a comparison between swayback, hyperlordotic and erect postures'. Together they form a unique fingerprint.Prizes
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Best Poster Presentation Award (Gold), Hong Kong Physiotherapy Association Conference 2023
Chan, H. W. (Recipient), Chan, Y. H. (Recipient), Huang, P. Y. (Recipient), Lam, K. T. (Recipient), Lam, W. Y. (Recipient) & Tsang, M. H. (Supervisor), 30 Jun 2023
Prize: Prize (research)