(F-221) Association of Age-Related Changes in: Mobility, Balance, and Maximum Force with Fall Injury Risk

Introduction:: Falls are a major cause of injury and financial burden. The ability to avoid injury from an unavoidable fall can be beneficial to those at risk, specifically older adults. An advantageous way to prevent injuries is by using upper extremities to absorb fall impact. The aim of this study is to identify clinically accessible measures of fall injury risk. Specifically, we tested for association of arm strength and measures of mobility and balance. The hypothesis is that arm strength is associated with increased mobility and balance.

Materials and Methods:: Eleven adults (5 females, 6 males) participated in this IRB approved study. Participants performed tests of seated grip strength, push off strength, and instrumented manual muscle tests (MMT). Six MMT (elbow flexion and extension, shoulder abduction and adduction, and shoulder flexion and extension) break tests were performed and tested for association with mobility and balance tests. Mobility and balance tests included the Mini-Balance Evaluation Systems Tests, timed up and go, four square step-test, and the Fall Risk for Older People survey. Pearson correlation was used to test for the association between the instrumented manual muscle tests and tests of mobility, hand grip strength, and the push off test. Associations were categorized as poor (R_­­² ≤ 0.01), fair (0.01 < R_­­² < 0.3), moderate (0.3 < R_­­² ≤ 0.5), good (0.5 R_­­² ≤ 0.7), or excellent (0.7 < R_­­² ≤ 1). (Table 1).


Results, Conclusions, and Discussions:: Descriptive statistics are reported as mean ± standard deviation.

Strength tests:

Elbow extension (EE) test: 18.86 ± 3.49 kg, elbow flexion (EF) test: 21.14 ± 5.79 kg, shoulder abduction (SABD) test: 18.9 ± 3.3 kg, shoulder adduction (SADD) test: 22.52 ± 4.1 kg, shoulder flexion (SF) test: 20.25 ± 3.71 kg, shoulder extension (SE) test: 19.77 ± 3.16 kg, hand grip (HG) test: 34.32 ± 11.73 kg and push-off (PO) test: 32.68 ± 14.24 kg.

Mobility tests:

Mini-BESTest (score out of 28): 26.91 ± 1.24, timed up and go (TUG): 8.72 ± 1.68 s, four square step test (FSST): 6.32 ± 1.41 s, fall risk of older people survey score (FROP): 3.55 ± 3.89.

(Table 2): Handgrip strength and the push-off test exhibited good correlation (R-squared = 0.62) with most measures of arm strength, elbow flexion and extension, shoulder adduction, flexion, and extension. The strongest (excellent) correlation existed between the maximum shoulder flexion force and hand grip strength (R-squared = 0.85). This is important since hand grip strength is one of the largest indicators of overall health. The average R-squared value was 0.24 which resembles a fair correlation between the MMTs with mobility tests and age changes. (Table 3)

The results from this study show that hand grip and push off tests may be used as a general indicator of upper extremity strength. They are clinically accessible method due to minimal equipment needed for testing. Future work is required to better understand the relationship between upper extremity strength and fall injury risk.


Acknowledgements (Optional): : I would like to thank Alex Hernandez, Amir Srour, and Ashlyn Bray for their assistance with data collection. As well as Dr. Borrelli for being the faculty principal investigator.


References (Optional): : 1 Sran, M. M., P. J. Stotz, S. C. Normandin, and S. N. Robinovitch. Age Differences in Energy Absorption in the Upper Extremity During a Descent Movement: Implications for Arresting a Fall. J. Gerontol. A. Biol. Sci. Med. Sci. 65A:312–317, 2010.
2 Bhandari, P. Correlation Coefficient | Types, Formulas & Examples. , 2021.at