Study Design. A 2 (group) × 2 (abdominal contraction) × 2 (reach activity) crossover mixed design with repeated measures for contraction and activity examined the effects of a loaded (4.6 kg) forward-reach activity and abdominal drawing-in maneuver (ADIM) on transversus abdominis (TrA) contraction in subjects with nonspecific low back pain (NSLBP) history versus controls.
Objective. We measured TrA contraction during a loaded forward-reach activity while using the ADIM and examined if a NSLBP history affects TrA activity.
Summary of Background Data. The ADIM supports trunk stability during function. Clinicians incorporate ADIM during patients' functional tasks. Pain-free individuals can sustain ADIM during function, such as forward-reach. However, this has not been tested in those with a NSLBP history.
Methods. Eighteen normal subjects and 18 subjects with a history of NSLBP participated. A blinded investigator recorded M-mode ultrasound imaging measurements of TrA thickness (mm) during 4 conditions as follows: (1) quiet standing without ADIM; (2) quiet standing with ADIM; (3) loaded forward-reach without ADIM; and (4) loaded forward-reach with ADIM.
Results. A mixed analysis of variance demonstrated a significant main effect for group (F [1, 34] = 5.404, P = 0.026; Figure 2), where TrA thickness was greater for NSLBP history (7.41 + 2.34 mm) versus controls (5.9 + 2.46 mm). A significant main effect was observed for abdominal contraction (F [1, 34] = 49.57, P < 0.0001; Figure 3), where TrA thickness was greater during ADIM (7.47 + 2.7 mm) versus without ADIM (5.84, 1.92 m). A significant main effect was observed for forward-reach activity (F [1, 34] = 12.79, P = 0.001; Figure 4), where TrA thickness was greater during a loaded forward-reach (7.04 + 2.6 mm) versus quiet standing (6.2 + 2.4 mm). There were no significant interactions.
Conclusion. Individuals can use a volitional pre-emptive ADIM for trunk protection during loaded forward-reach, potentially reducing injury risk. A NSLBP history increases TrA activation during ADIM, suggesting an enhanced protective role.
Level of Evidence: 2
M-mode ultrasound imaging measured transversus abdominis contraction in 18 normal subjects and 18 subjects with nonspecific low back pain history (NSLBP) during loaded forward-reach with and without abdominal drawing-in maneuver (ADIM). Significant differences were found in muscle thickness for group (NSLBP > controls), abdominal contraction (ADIM > no ADIM), and reach activity (reach > rest). This suggests a protective utility for ADIM.
*Center for Rehabilitation Research, SAHS, Texas Tech University Health Sciences Center, Lubbock, TX; and
†Doctor of Physical Therapy Program, Campbell University, Buies Creek, NC.
Address correspondence and reprint requests to Phillip S. Sizer, Jr, PT, PhD, 3601 4th St., Stop 6280, Lubbock, TX 79430-6280; E-mail: firstname.lastname@example.org
Acknowledgment date: April 25, 2013. Revision date: September 23, 2013. Acceptance date: September 25, 2013.
The device(s)/drug(s) is/are FDA-approved or approved by corresponding national agency for this indication.
No funds were received in support of this work.
No relevant financial activities outside the submitted work.