ABSTRACT
OBJECTIVE: The purpose of this study was to investigate changes in resting and/or contraction thickness of the transversus abdominis (TrA) muscle after dry needling (DN) of the lumbar multifidus (LM) in asymptomatic participants. METHODS: A randomized controlled laboratory trial with crossover design was performed. Forty-seven healthy individuals who had not experienced low back pain in the previous 6 months were randomly assigned to receive DN to the LM or a sham-DN intervention. Participants received both interventions separated at least 7 days apart. They were instructed on how to perform a concentric contraction of TrA. Resting and contraction thicknesses of the TrA were obtained through real-time ultrasound measurements before and immediately after each intervention by an assessor blinded to the intervention received. Data from 4 individuals had to be excluded because of poor image quality. RESULTS: Two-way analysis of variance revealed a significant contraction with treatment interaction (F[1,42] = 11.489; P = .002). Simple main effects using paired-samples t tests and a Bonferroni post hoc analysis revealed differences in contracted states of the TrA for DN vs sham-DN (P = .009) and between contracted and resting states for the DN group (P = .001): after DN, TrA thickness at rest exhibited a mean decrease of 0.03 cm and a mean increase of 0.05 cm during contraction. CONCLUSION: This study suggests that application of DN to LM was accompanied by a decreased resting thickness and an increased contraction thickness of the TrA in asymptomatic participants.
Subject(s)
Abdominal Muscles/physiology , Acupuncture Therapy/methods , Low Back Pain/therapy , Pain Measurement , Paraspinal Muscles/physiopathology , Adult , Cross-Over Studies , Double-Blind Method , Female , Healthy Volunteers , Humans , Low Back Pain/diagnostic imaging , Lumbosacral Region , Male , Muscle Contraction/physiology , Muscle Relaxation/physiology , Paraspinal Muscles/diagnostic imaging , Reference Values , Ultrasonography/methodsABSTRACT
The title compounds, 1-chloro-3,6-dimethoxy-2,5-dimethylbenzene, (IIIa), and 1-chloro-3,6-dimethoxy-2,4-dimethylbenzene, (IIIb), both C10H13ClO2, were obtained from 2,5- and 2,6-dimethyl-1,4-benzoquinone, respectively, and are intermediates in the synthesis of ammonium quinone derivatives. The isomers have different substituents around the methoxy groups and crystallize in different space groups. In both molecules, the methoxy groups each have different orientations with respect to the benzene ring. In both cases, one methoxy group lies in the plane of the ring and can participate in conjugation with the aromatic system, while the second is almost perpendicular to the plane of the aromatic ring. The C-O-C bond angles around these substituents are also different: 117.5 (4) and 118.2 (3) degrees in (IIIa) and (IIIb), respectively, when the methoxy groups lie in the plane of the ring, and 114.7 (3) and 113.6 (3) degrees in (IIIa) and (IIIb), respectively, when they are out of the plane of the ring.
