Changes in Motor Performance: Indicators of Fall Risks After Bariatric Surgery

Adults classified as obese have triple the risk of experiencing a fall-related injury, and the likelihood of sustaining an injury after falling triples when there is an increase in body mass index (BMI) from the overweight to the obese range (Messer, 2008). Increases in fall risks compromise clients’ safety in home and community living.

One factor contributing to fall risks for these adults includes reported difficulty in walking. Compared with normal-weight adults, adults with obesity try to maintain stability by walking more slowly and spending more time with their feet in contact with the ground. Although these walking patterns are done in an attempt to increase stability, they actually increase the risk of falls. Even after bariatric surgery (BSX), adults still report falling (Berarducci, Haines, & Murr, 2009). Despite the effects of obesity on fall risks, we know little about whether weight loss after BSX improves the walking patterns needed for safe movement in completing everyday tasks. These results would inform future studies determining the benefits of movement-focused interventions to reduce fall risks after BSX.

The purpose of this study was to examine differences in walking in adults with obesity before and after BSX. Sixteen adults participated in this longitudinal study in the Motor Development Lab (mean BMI = 41.89 kg/m², SD = 4.83; mean age = 41.55 yr old, SD = 8.31) for two visits: a pretest before BSX and a posttest 1 yr after BSX. Clients walked 60 ft for 25 trials in five conditions: initial baseline on flat ground; crossing low, medium, and high obstacles; and final baseline on flat ground. Obstacles resembled the standard heights of physical environmental barriers typically encountered by adults in everyday life: a door threshold (4 cm), small step (11 cm), and tall step (16 cm). The timing and distance of participants’ steps were collected (Gaitrite, Inc.). A 2 visit × 3 obstacle repeated-measures analysis of variance was conducted to examine differences in velocity, time spent supporting weight on one leg (i.e., single-limb support time), and time spent supporting weight on both legs (i.e., double-limb support time).

Adults showed differences in velocity across conditions, F(4, 60)= 20.04; they had the lowest velocity at the highest obstacle (all ps < .001). They also showed differences by condition in single-, F(4, 60) = 86.27, p < .001, and double-limb support time, F(4, 60) = 4.28, p < .01. Single-limb support time was lowest at the final baseline and highest at the highest obstacle (all ps < .001). Single-limb support time became progressively higher as obstacle height increased (all ps < .001). Double-limb support time was higher at the initial baseline compared with the first obstacle (p < .01) and compared with the last baseline (p < .01). Most interesting, there was a main effect for visit with double-limb support time, F(1, 15) = 15.28, p < .01; double-limb support time decreased from Visit 1 to 2.

Obstacles posed a challenge for adults undergoing BSX. However, improved motor performance was observed after surgery. These results support the utility of examining mobility in this population. Limitations of the current study include testing clients’ mobility in a lab setting and the need to use functional performance measures to capture clients performing mobility activities. These limitations are currently being addressed with studies underway.

References

Berarducci, A., Haines, K., & Murr, M. M. (2009). Incidence of bone loss, falls, and fractures after Roux-en-Y gastric bypass for morbid obesity. Applied Nursing Research: ANR, 22, 35–41. http://dx.doi.org/10.1016/j.apnr.2007.03.004

Messier, S. P. (2008). Obesity and osteoarthritis: Disease genesis and nonpharmacologic weight management. Rheumatic Diseases Clinics of North America, 34, 713–729. http://dx.doi.org/10.1016/j.rdc.2008.04.007