Lee S1, Suzuki T1, Satoh S1, Hashimoto J1, Satoh A2
1Aomori University of Health and Welfare, Department of Physical Therapy, Aomori, Japan, 2Hirosaki University of Health and Welfare, Department of Nursing, Hirosaki, Japan
Background: Ground reaction force and moments of force are greatly influenced by factors such as acceleration and fluctuations in center of gravity, important elements of a stable gait. However, the nature of the influence of incline changes during ambulation on ground reaction force and moments of force has not yet been clarified; thus, an investigation of ambulation in various environments is needed.
Purpose: Here we examined the impact of differences in inclination during ambulation on ground reaction force and moments of force to obtain findings indicative of a stable ambulation method.
Methods: This study included 9 healthy men. The study received approval from the Aomori University of Health and Welfare Institutional Review Board. Ground reaction force and moments of force were measured for 10 seconds at 1000 Hz for each respective protocol using a Treadmetrix device equipped with a built-in force plate. The walking speed used for each protocol was 4.5 km/h, and 0 degrees was used as the grading protocol standard for comparison. Next, subjects were asked to alternate between tasks calling for walking up and down inclines; each sat for a 1-minute rest period between protocols. The increasing gradient protocols were set to test 5, 10, 15, and 20 degrees, and the decreasing gradient protocols were set to test -5, -10, -15, and -20 degrees. For the analysis, multiple comparisons were performed using one-way analysis of variance. Values of p 0.05 were considered statistically significant.
Results: Regarding ground reaction force, the longitudinal component (Fy) was significantly lower than 0 (-5.22 N) degrees for each of the increasing gradient ambulation protocols set to test 10 (-125.4 N), 15 (-132.2 N), and 20 (-154.8 N) degrees (p 0.05, in each). During the decreasing gradient ambulation protocols, Fy was significantly lower than 0 degrees (flat ground) at -15 (-105.0 N) and -20 (-150.9 N) degrees (p 0.05, in each). In contrast, regarding moments of force, vertical moments (Mz) had significantly higher force for all inclines compared to the 0-degree incline during the increasing gradient ambulation protocols, while Mz force was significantly higher than the 0-degree incline for all inclines except -5 degrees (p 0.05, in each).
Conclusion(s): A decrease in Fy and increase in Mz were observed during ambulation on an incline compared to flat ground due to the influence of the shift in the center of gravity with respect to the incline. Fy in particular became more pronounced during ambulation in the backward direction as the angle of increasing and decreasing gradients increased. In essence, decreasing and increasing gradients by 10 degrees or more can present new risks of backward fall events in people with pronounced fall tendencies or those with a poor balance ability. As such, we believe that weight and speed adjustments during ambulation in physical therapy can contribute to stable and effective gait training.
Implications: Here we obtained knowledge of fall-related factors during inclined ambulation and demonstrated the ability to achieve a stable gait through physical therapy and rehabilitation.
Keywords: Gradient, Ground reaction force, Moment
Funding acknowledgements: The present work was supported by the Aomori University of Health and Welfare (AUHW 2018).
Purpose: Here we examined the impact of differences in inclination during ambulation on ground reaction force and moments of force to obtain findings indicative of a stable ambulation method.
Methods: This study included 9 healthy men. The study received approval from the Aomori University of Health and Welfare Institutional Review Board. Ground reaction force and moments of force were measured for 10 seconds at 1000 Hz for each respective protocol using a Treadmetrix device equipped with a built-in force plate. The walking speed used for each protocol was 4.5 km/h, and 0 degrees was used as the grading protocol standard for comparison. Next, subjects were asked to alternate between tasks calling for walking up and down inclines; each sat for a 1-minute rest period between protocols. The increasing gradient protocols were set to test 5, 10, 15, and 20 degrees, and the decreasing gradient protocols were set to test -5, -10, -15, and -20 degrees. For the analysis, multiple comparisons were performed using one-way analysis of variance. Values of p 0.05 were considered statistically significant.
Results: Regarding ground reaction force, the longitudinal component (Fy) was significantly lower than 0 (-5.22 N) degrees for each of the increasing gradient ambulation protocols set to test 10 (-125.4 N), 15 (-132.2 N), and 20 (-154.8 N) degrees (p 0.05, in each). During the decreasing gradient ambulation protocols, Fy was significantly lower than 0 degrees (flat ground) at -15 (-105.0 N) and -20 (-150.9 N) degrees (p 0.05, in each). In contrast, regarding moments of force, vertical moments (Mz) had significantly higher force for all inclines compared to the 0-degree incline during the increasing gradient ambulation protocols, while Mz force was significantly higher than the 0-degree incline for all inclines except -5 degrees (p 0.05, in each).
Conclusion(s): A decrease in Fy and increase in Mz were observed during ambulation on an incline compared to flat ground due to the influence of the shift in the center of gravity with respect to the incline. Fy in particular became more pronounced during ambulation in the backward direction as the angle of increasing and decreasing gradients increased. In essence, decreasing and increasing gradients by 10 degrees or more can present new risks of backward fall events in people with pronounced fall tendencies or those with a poor balance ability. As such, we believe that weight and speed adjustments during ambulation in physical therapy can contribute to stable and effective gait training.
Implications: Here we obtained knowledge of fall-related factors during inclined ambulation and demonstrated the ability to achieve a stable gait through physical therapy and rehabilitation.
Keywords: Gradient, Ground reaction force, Moment
Funding acknowledgements: The present work was supported by the Aomori University of Health and Welfare (AUHW 2018).
Topic: Health promotion & wellbeing/healthy ageing; Health promotion & wellbeing/healthy ageing
Ethics approval required: Yes
Institution: Aomori University of Health and Welfare
Ethics committee: Research Ethics Committee
Ethics number: No. 1704
All authors, affiliations and abstracts have been published as submitted.
