Singh B1, Camilleri D1, Sharma A2, Van Artsdalen A1
1California State University, Physical Therapy, Fresno, United States, 2Central Connecticut State University, New Britain, United States
Background: Obese individuals may have difficulty performing basic rehabilitation exercises like squat and lunge. Balance and adipose tissue restriction, are major issues for obese individuals, which could have implications on balance biomechanics. Despite potential for biomechanical differences from normal weight subjects, the influence of obesity on the performance of squat and lunge has not been documented.
Purpose: The purpose of this study was to analyze and compare balance biomechanics of obese females, as measured by sway area of center of pressure (COP) while performing squat and lunge exercises.
Methods: Ten obese (BMI > 30 kg/m2) female subjects age 37.4±3.7 years, BMI 39.2±3.7 kg/m2 and ten normal weight (BMI 23 kg/m2), age matched females, BMI 21.6±2.3 kg/m2, volunteered for the study. Infrared marker triads were applied to the lower limbs, pelvis, and trunk to generate an anatomical model using three dimensional motion analysis system (Optotrak, NDI). Testing session included: Quiet standing eyes open for 30 seconds(s). Squatting down, feet shoulder width apart, holding for 3s at 3 different knee angles: 100, 110, and 120 degrees. Lunging at 3 different distances, holding for 3s at 1, 1.1 and 1.2 times subject's tibial length. Sway area was defined as area of ellipse (cm2) enclosing 95% of COP points over 3s. A group (obese vs normal weight) by level of difficulty ANOVA was used to find differences in sway area across three levels of difficulty for the squat and lunge. SPSS 22.0 was used for analysis with p-value 0.05.
Results: For obese females, the sway area for eyes open on foam (7.27 ± 2.7 cm2) was significantly greater than eyes open (2.36 ± 1.5) and eyes closed (2.5 ± 1.3) on floor (p=0.001). Sway area for squat 120 (2.56 ± 1.4) was similar to squat 110 (4.04 ± 2.3) and squat 100 (3.18 ± 1.3) whereas lunge 1.2 (18.9 ± 9.4) was significant greater than lunge 1 (13.91 ± 5.4) and lunge 1.1 (9.93 ± 2.5) (p-values 0.001). Comparing between obese and normal weight, sway area was not different between obese and normal weight females for squat 60 (p=0.62) squat 70 (p=0.16) and squat 80 (p=0.11). For the lunge, sway area was higher for obese females for all three levels of lunge, lunge 1 (p=0.004), lunge 1.1 (p=0.002) and lunge 1.2 (p=0.001). The lunge had greater sway area as compared to standing as well as squat activities (p 0.001).
Conclusion(s): Lunging activity was more challenging for obese females as shown by greater sway area and sway velocity. The area for lunge 1.1 was less than both lunge 1 and lunge 1.2 suggesting that the shortest stride length might not be the most stable for obese individuals. There were no differences in the three squat depths, indicating that squat may be a better exercise choice for obese individuals with fall risk.
Implications: identifying the underlying biomechanical issues and the strategies used by obese individuals during the common rehabilitation exercises will provide a rationale to set different recommendations for the obese population.
Keywords: Balance, Obese, Biomechanics
Funding acknowledgements: California State University Provost Award
Purpose: The purpose of this study was to analyze and compare balance biomechanics of obese females, as measured by sway area of center of pressure (COP) while performing squat and lunge exercises.
Methods: Ten obese (BMI > 30 kg/m2) female subjects age 37.4±3.7 years, BMI 39.2±3.7 kg/m2 and ten normal weight (BMI 23 kg/m2), age matched females, BMI 21.6±2.3 kg/m2, volunteered for the study. Infrared marker triads were applied to the lower limbs, pelvis, and trunk to generate an anatomical model using three dimensional motion analysis system (Optotrak, NDI). Testing session included: Quiet standing eyes open for 30 seconds(s). Squatting down, feet shoulder width apart, holding for 3s at 3 different knee angles: 100, 110, and 120 degrees. Lunging at 3 different distances, holding for 3s at 1, 1.1 and 1.2 times subject's tibial length. Sway area was defined as area of ellipse (cm2) enclosing 95% of COP points over 3s. A group (obese vs normal weight) by level of difficulty ANOVA was used to find differences in sway area across three levels of difficulty for the squat and lunge. SPSS 22.0 was used for analysis with p-value 0.05.
Results: For obese females, the sway area for eyes open on foam (7.27 ± 2.7 cm2) was significantly greater than eyes open (2.36 ± 1.5) and eyes closed (2.5 ± 1.3) on floor (p=0.001). Sway area for squat 120 (2.56 ± 1.4) was similar to squat 110 (4.04 ± 2.3) and squat 100 (3.18 ± 1.3) whereas lunge 1.2 (18.9 ± 9.4) was significant greater than lunge 1 (13.91 ± 5.4) and lunge 1.1 (9.93 ± 2.5) (p-values 0.001). Comparing between obese and normal weight, sway area was not different between obese and normal weight females for squat 60 (p=0.62) squat 70 (p=0.16) and squat 80 (p=0.11). For the lunge, sway area was higher for obese females for all three levels of lunge, lunge 1 (p=0.004), lunge 1.1 (p=0.002) and lunge 1.2 (p=0.001). The lunge had greater sway area as compared to standing as well as squat activities (p 0.001).
Conclusion(s): Lunging activity was more challenging for obese females as shown by greater sway area and sway velocity. The area for lunge 1.1 was less than both lunge 1 and lunge 1.2 suggesting that the shortest stride length might not be the most stable for obese individuals. There were no differences in the three squat depths, indicating that squat may be a better exercise choice for obese individuals with fall risk.
Implications: identifying the underlying biomechanical issues and the strategies used by obese individuals during the common rehabilitation exercises will provide a rationale to set different recommendations for the obese population.
Keywords: Balance, Obese, Biomechanics
Funding acknowledgements: California State University Provost Award
Topic: Musculoskeletal; Human movement analysis; Outcome measurement
Ethics approval required: Yes
Institution: University of Iowa
Ethics committee: University of Iowa Institutional Review Board
Ethics number: 2388
All authors, affiliations and abstracts have been published as submitted.
