<![CDATA[Journal of Orthopaedic & Sports Physical Therapy - Barbara A. Springer, PT, PhD, OCS, SCS]]> http://www.jospt.org/barbaraaspringer Wed, 30 Apr 2008 09:05:25 EST 0 Characterization of Lateral Abdominal Muscle Thickness in Persons With Lower Extremity Amputations http://www.jospt.org/issues/articleID.1335/article_detail.asp Barbara A. Springer, Norman W. Gill
STUDY DESIGN: Retrospective review. OBJECTIVES:  To describe bilateral thickness of the lateral abdominal muscles at baseline and during an abdominal drawing-in maneuver (ADIM) in individuals with unilateral transtibial (TTA) or transfemoral (TFA) amputations. BACKGROUND: Although side-to-side symmetry of lateral abdominal muscles thickness has been established in healthy individuals, the degree of symmetry in those with unilateral lower extremity amputations remains unknown. Differences in lateral abdominal muscle thickness may exist based on prior findings of asymmetry and differences measured based on level of amputation in both the size and function of the iliopsoas and back extensor muscles. METHODS AND MEASURES: Seventy patients (69 males, 1 female) with traumatic unilateral lower extremity amputations (TTA, n = 39; TFA, n = 31) received a rehabilitative ultrasound imaging examination. Absolute thickness of the transversus abdominis (TrA) and the external and internal oblique muscles combined (EO+IO) were assessed bilaterally at baseline and during the ADIM. Symmetry was assessed using relative muscle thickness values at baseline. Percent increase in muscle thickness during the ADIM was used to investigate muscle function. Separate 2-by-2 mixed-model ANOVAs were used to compare both within-group (side of amputation versus nonamputated side) and between-group (TTA versus TFA) differences for thickness and function of the TrA and the EO+IO muscles. RESULTS: On the side of the amputation, the relative baseline thickness of the EO+IO measurement was greater (P<.05), while the relative baseline thickness of the TrA muscle was smaller (P<.05). But the mean differences side to side were small (1.3%) and unlikely to be clinically significant. Further, there were no differences in baseline muscle thickness between groups for the TrA (P = .95) or the EO+IO (P = .94) muscles. For thickness measurements during the ADIM, the TrA showed no side-to-side (P = .74) or group (P = .07) differences. Similarly, no side-to-side (P = .60) or group (P = .09) differences were found in the EO+IO thickness during the ADIM. CONCLUSIONS: Despite the limitations of retrospective review, these findings provide an initial reference data set for future studies. Bilateral symmetry of the lateral abdominal wall muscle thicknesses at baseline and during the ADIM for those with unilateral lower extremity amputations is comparable to healthy individuals. Future studies should consider the potential influences of low back pain and gait training on symmetry of muscle thickness and muscle function based on level of amputation.

J Orthop Sports Phys Ther. 2007;37(10):635-643, published online 29 August 2007. doi: 10.2519/jospt.2007.2532

KEY WORDS: rehabilitative ultrasound imaging, sonography, transfemoral, transtibial, transversus abdominis

]]> http://www.jospt.org/issues/articleID.1335/article_detail.asp Relationships Among Lateral Abdominal Muscles, Gender, Body Mass Index, and Hand Dominance http://www.jospt.org/issues/articleID.1035/article_detail.asp Barbara A. Springer, Billie J. Mielcarek, Tiffany K. Nesfield, Deydre S. Teyhen

Study Design: Exploratory.

Objectives: To explore whether hand dominance, gender, and body mass index (BMI) influence the thickness of the lateral abdominal muscles as measured by ultrasound imaging. To document the extent of improvement in response stability when an average of multiple measures was utilized.

Background: Ultrasound imaging is a relatively new tool used to assess the lateral abdominal muscles. A better understanding of how these muscles contract in a healthy population can provide a reference for comparison to patients with low back pain (LBP).

Methods and Measures: Thirty-two healthy participants (17 males, 15 females) aged 18 to 45 years (mean ± SD, 31.9 ± 7.8 years) were studied. Measurements of muscular thickness of the lateral abdominal muscles were obtained bilaterally while the subjects were at rest, and while they performed the abdominal drawing-in maneuver. To determine the possible influence of hand dominance and gender on muscle thickness, t tests were used. Correlation coefficients were used to assess the relationship between BMI and muscle thickness. Standard error of the measurement was used to assess response stability of the ultrasound imaging technique.

Results: No differences in the thicknesses of the transversus abdominis (TrA) muscle were measured during rest or while contracted, based on hand dominance (P≥.73). Men had greater muscular thickness (P<.01), while the TrA in women represented a greater proportion of the total lateral abdominal muscles (P<.01). BMI was positively associated with muscle thickness (r≥.66). Compared to a singular measurement, response stability improved by greater than 50% when an average of 3 measurements was used.

Conclusions: Future researchers should assess the need to control for gender and BMI as potential covariates in ultrasound imaging studies of the lateral abdominal muscles. Asymmetry in the lateral abdominal muscles in those with LBP would be in direct contrast to the bilateral symmetry measured in those without LBP. J Orthop Sports Phys Ther. 2006;36(5):289-297. doi:10.2519/ jospt.2006.2217

Key Words: low back pain, lumbar stabilization, real-time ultrasound imaging, sonography, transversus abdominis

]]> http://www.jospt.org/issues/articleID.1035/article_detail.asp