Undergraduate Student Arizona State University Chandler, Arizona, United States
Introduction:: Fall Risk is a public health concern that has plagued the American population. The numbers have now increased to 3 million older adults being hospitalized in the emergency room due to fall injuries1. When older adults fall, they are at risk for severe injuries such as broken bones and head trauma, so it is imperative to reverse this trend. This study aims to find solutions to help lower that number over the upcoming years. With medicine constantly being improved, it comes into question if the lack of physical activity in the American population is responsible for the increase in fall accidents. It is reported that 75% of Americans are failing to exercise properly2. Both the number of fall accidents and the number of individuals failing to exercise properly are increasing over time, so it comes into question if these variables are related.
The goal of this study was to investigate if proper levels of physical activity correspond to lower fall risk in younger adults. A separate study must be conducted to understand if those results translate to older populations. The reason why younger adults were tested before older adults, despite older adults having greater fall risk3, was to see if even at a younger age, physical activity levels play a crucial role in fall risk. It was hypothesized that the athletes would display better balance and lower fall risk compared to the nonathletes due to their high muscle memory from their experience in athletics.
Materials and Methods:: To determine if exercise levels affect fall risk, there were two groups tested: nonathletes and athletes. In order for a subject to be qualified as an athlete, they must have been between the ages of 18 and 24. They had to play a sport for a minimum of five years while continuing to play it on a weekly basis. The nonathletes were adults between the ages of 18 and 24 and were not involved in any consistent level of physical activity.
To test the fall risk between the two groups, a dual-perturbation treadmill system was used. Each subject completed three 2-minute walking trials on the treadmill. Eight perturbations were administered randomly throughout the two minutes. Each trial consisted of a different type of perturbation (medial/lateral, acceleration, and deceleration). The subject’s reaction to each perturbation was measured via an IMU placed on the sacrum. This is approximately where the subject’s center of mass is located4. The peak acceleration of the sacrum was measured during each trial. The recovery time for each subject was also measured by determining how long it took the subject to return to normal gait during the perturbation. This was done by using the same acceleration data presented by the IMU.
To test for significance between the two groups, the data from the first and last perturbation was analyzed. 2-way anova tests were run for both the peak acceleration and the recovery time to determine if there was a significant difference in performance between the athletes and nonathletes.
Results, Conclusions, and Discussions:: After all four subjects finished, the data was analyzed in MATLAB. The peak acceleration in the superior/inferior direction of the first and last slip was compared between the two groups for all three types of perturbations. This was also done with the slip time. After running the 2-way anova, it was determined that the difference in performance between the two groups was not significant.
While it cannot be claimed from this study that athletes have better balance compared to nonathletes, there are a few significant trends observed in the data. All of the subjects’ accelerations for each trial was able to be graphed separately. In the graphs for acceleration-based perturbations, it was observed that the athlete was able to significantly reduce their acceleration from 50 m/s2 on their first slip to 20 m/s2 on their last slip. Meanwhile, the nonathlete initially slipped at 45 m/s2 and then slipped 43 m/s2 during the last perturbation. This trend showed that the athlete was able to adjust and learn to react to the perturbations quicker than the nonathlete. One of the reasons why trends like this were not significant enough to reject the null hypothesis was because of the sample size. This study functioned as a pilot study, and if there were more participants in each group, then it is more likely that the difference in performance would be larger.
One significant takeaway that was not expected from this study was that there is potential to train subjects to react to perturbations. If the athletes were able to improve their performance in just one trial, it is fair to wonder how any subject, not just athletes, can improve their reaction with a training program that involves them being perturbed across multiple sessions. Fall accidents have caused numerous injuries, and if having an athletic background is found to have no effect on fall risk, then it is important to find other ways to lower it such as perturbation-based training like this study may indicate. Other future studies could include performing the same exact study but with older adult athletes and nonathletes.
Acknowledgements (Optional): : I would like to thank Dr Lockhart for teaching me about the importance of fall and for his guidance on this study. I would also like to thank PhD candidate, Seong Moon, for assisting me with data collection.
References (Optional): : [1] Facts About Falls | Fall Prevention | Injury Center | CDC. (2021, December 1). Www.cdc.gov. https://www.cdc.gov/falls/facts.html#:~:text=Falls%20Are%20Serious%20and%20Costly&text=Each%20year%2C%203%20million%20older
[2] Archive, V. A., & feed, G. author R. (2022, August 30). 75% of American adults are failing at exercise: CDC report. https://nypost.com/2022/08/30/75-of-american-adults-are-failing-at-exercise-cdc-report/
[3] Talbot, L. A., Musiol, R. J., Witham, E. K., & Metter, E. J. (2005). Falls in young, middle-aged and older community dwelling adults: perceived cause, environmental factors and injury. BMC Public Health, 5(1). https://doi.org/10.1186/1471-2458-5-86
[4] Patoz, A., Lussiana, T., Breine, B., Gindre, C., & Malatesta, D. (2022). A Single Sacral-Mounted Inertial Measurement Unit to Estimate Peak Vertical Ground Reaction Force, Contact Time, and Flight Time in Running. Sensors, 22(3), 784. https://doi.org/10.3390/s22030784
