Dynamic Chiropractic – June 3, 2011, Vol. 29, Issue 12

Research Abstracts From the Journal of Manipulative and Physiological Therapeutics

March-April Abstracts Volume 34, Issue 3

The JMPT is the premier scientific journal of the chiropractic profession, dedicated to the advancement of chiropractic health care.

The National University of Health Sciences, owner of the journal, upholds the journal's compliance with the highest publication standards, which expressly support editorial freedom and best publication practices. The JMPT is an independent publication that strives to provide the best scientific information that improves health care practice and future research.

Identifying Patients With Mechanical Neck Pain Who Will Respond Rapidly to Manipulative Interventions

Manuel Saavedra-Hernandez, PT, et al.

Objective: The purpose of this study was to identify the prognostic factors for individuals with mechanical neck pain likely to experience improvements in both pain and disability after the application of an intervention including cervical and thoracic spine thrust manipulations.

Methods: Patients presenting with mechanical neck pain participated in a prospective single-arm trial. Participants underwent a standardized examination and then received a series of thrust manipulations directed toward the cervical, cervicothoracic, and thoracic spine. Participants were classified as having achieved a successful outcome at the second and third sessions based on their perceived recovery. Potential prognostic variables were entered into a stepwise logistic regression model to determine the most accurate set of variables for the prediction of treatment success.

Results: Data from 81 subjects were included in the analysis, of which 50 experienced a successful outcome (61.7%). Five variables including pain intensity greater than 4.5 points; cervical extension less than 46°; presence of hypomobility at T1; a negative upper limb tension test and female sex were identified. If four of five variables were present (likelihood ratio, +1.9), the likelihood of success increased from 61.7% to 75.4%.

Conclusions: This study identified several prognostic clinical factors that can potentially identify, a priori, patients with neck pain who are likely to experience a rapid response to the application of an intervention including both cervical and thoracic spine manipulations. However, no combination of the variables was able to dramatically increase the posttest probability.

Chiropractic Manipulative Therapy and Low-Level Laser Therapy for Cervical Facet Dysfunction

Lindie Saayman, MT (Chiro), et al.

Purpose: The aim of this study was to determine the short-term effect of chiropractic joint manipulation therapy (CMT) and low-level laser therapy (LLLT) on pain and range of motion in the management of cervical facet dysfunction.

Methods: Sixty ambulatory women between the ages of 18 and 40 years with cervical facet joint pain of more than 30 days duration and normal neurologic examination were randomized to receive one of three treatment options: (1) CMT of the cervical spine, (2) LLLT applied to the cervical facet joints, or (3) a combination of CMT and LLLT. Each participant received six treatments in three weeks. The main outcome measures were as follows: the Numerical Pain Rating Scale, Neck Disability Index, Cervical Range of Motion Instrument, and Baseline Digital Inclinometer. Measurements were taken during weeks one (baseline), two, three and four.

Results: No differences existed between the three groups at baseline. A significant difference was seen between groups 1 (CMT) and 2 (LLLT) for cervical flexion, between groups 1 (CMT) and 3 (CMT + LLLT) for cervical flexion and rotation, and between groups 2 (LLLT) and 3 (CMT + LLLT) for pain disability in everyday life, lateral flexion, and rotation.

Conclusion: All three groups showed improvement in the primary and secondary outcomes. A combination of CMT and LLLT was more effective than either of the two on their own. Both therapies are indicated as potentially beneficial treatments for cervical facet dysfunction. Further studies are needed to explore optimal treatment procedures for CMT and LLLT and the possible mechanism of interaction between therapies.

Effect of a Closed-Chain, Eccentric Training Program on Hamstring Injuries in Cheerleaders

Jay Greenstein, DC, et al.

Objective: Hamstring injuries are a common occurrence among professional football cheerleaders. The purpose of this study is to identify the effects of an eccentric, closed-chain hamstring exercise intervention on hamstring injury-associated pain during the course of the football season among professional football cheerleaders.

Methods: Forty-three female cheerleaders participated in an eccentric, closed-chain hamstring exercise intervention protocol provided by doctors of chiropractic that incorporated loops of elastic-band or Thera-Band Loops (Hygenic Corporation, Akron, OH) during practice and at home during the regular football season. Hamstring injury-related pain was assessed in June, during team selection; in September, at the start of the season; and in December, at the end of season. No intervention was applied between June and September, although the sample participated in four hours of practice two to three times per week. The intervention was applied to the entire sample regardless of hamstring injury-related pain during the regular football season between September and December. The interventions included two exercises and were completed bilaterally two times per week at each biweekly practice, and were encouraged to be done at least three additional times per week at home on nonpractice days.

Results: Among the subsample who reported hamstring-related injury pain between June and September, the exercise intervention significantly decreased (P < .007) pain between September (6.07 ± 0.58) and December (3.67 ± 0.65).

Conclusions: The eccentric, closed-chain hamstring exercise intervention reduced hamstring injury-related pain among this group of professional football cheerleaders.

Effect of Two Lumbar Spine Postures on Transversus Abdominis Muscle Thickness

Rafael Pinto, PT, MSc, et al.

Objective: The present study investigated the effect of two different lumbar spine postures, neutral and flexed lumbar postures, on transversus abdominis (TrA) muscle function during a voluntary contraction (hollowing and draw-in maneuver) in people with and without low back pain (LBP).

Methods: Thirty participants with LBP and 30 healthy participants were recruited for this cross-sectional study. Transversus abdominis muscle function was measured as a change in thickness with ultrasound imaging. Participants performed voluntary TrA contraction in a supine-lying position with the lumbar spine in neutral and flexed postures. Data were analyzed using a two-way (groups, postures) analysis of variance.

Results: Lumbar posture influenced TrA function during a voluntary contraction in people with and without LBP. There was a significant main effect of posture (F1,58 = 16.140, P < .001). Neutral lumbar posture improved participants' ability to recruit TrA in both group (mean difference, 7.5%; 95% confidence interval, 3.8%-11.3%). No significant differences were found between healthy subjects and those with LBP.

Conclusions: The results of the present study showed that, in subjects performing a voluntary TrA contraction, the neutral lumbar posture improves the ability to increase change in TrA thickness. This study found no significant difference in TrA thickness change between healthy subjects and those with nonspecific LBP.

Maturation in Rate of High-Velocity, Low-Amplitude Force Development

John Triano, DC, PhD, et al.

Objectives: The purpose of this study was to examine the maturation of force development during a thoracic high-velocity, low-amplitude displacement procedure at stages throughout chiropractic education. The hypothesis posed a natural development in rate of force directly related to the duration of experience. The analysis sought to define interrelationships between key characteristics within the procedure.

Methods: Fifty volunteers (17 women and 33 men) from a Canadian chiropractic college participated in this study. Participants were block randomized into five cohorts of 10 subjects, representing years one to four and graduates with more than five years of practice experience. Participants performed a hypothenar transverse push procedure on the upper thoracic spine, with the subjects lying on a force-sensing table. The average of three force-time profiles of the procedures was compared across cohorts using analysis of variance for differences between groups, and pairwise comparisons by Scheffe test, using Holms method for P value adjustment.

Results: Peak force, force rate, and rise time revealed strong differences based on cohort (P < .001). A natural maturation in high-velocity, low-amplitude force development occurs during training. Little change in peak force occurs in the first two years. The majority of development occurs in year three, with tapering through year four. A reciprocal coupling exists between peak force and force rate.

Conclusions: Group means revealed statistically significant and monotonic increase in force rate, a decreased rise time, and decreased peak force during delivery of the therapeutic peak force. These differences paralleled growth in experience but with an asymptotic leveling of change between the fourth year of training and five years of clinical practice experience. This study showed a systematic maturation in performance associated with educational experience. The reciprocal coupling between rate of force development and peak force created a relatively stable impulse.

Relationship Between Dens Height and Alar Ligament Orientation

Peter Osmotherly, MMedSci, et al.

Objective: This study examined the anatomical assumptions underlying multiplanar alar ligament stress testing. The alar ligament has been described as occurring in one of three planes: caudocranial, horizontal, and craniocaudal. This has been stated to result from variation in dens height. Stress testing in all three planes is suggested, with increased translation present in all positions to infer instability.

Methods: Computed tomography scans with no diagnosed bony or ligamentous abnormally were prospectively collected over a three-month period from a teaching hospital in Newcastle, Australia, and sequentially analyzed. The height of the dens relative to the occipital condyles was measured using McRae's line and the bimastoid line. The orientation of the alar ligament was measured relative to the vertical axis of the dens as well as a vertical line defined by specified occipital and spinal bony landmarks. These results were correlated with dens height.

Results: After exclusions, 42 individual computed tomography studies were analyzed, yielding 64 clearly discernible ligaments. A vertical line derived from the digastric line provided the smallest variation in results. The mean ligament orientation given by this measure was 110.06° (85°-127°). There was no correlation between measured dens height relative to the occiput and ligament orientation.

Conclusion: Our findings reinforce the existence of normal anatomical variation in dens height and alar ligament orientation. However, variation in dens height as a cause of variation in ligament orientation was not supported by this study.

Comparison of Two Assessment Protocols to Target Abdominal Muscle Endurance

Isabelle Pagé, et al.

Objective: The purpose of this study was to compare two variations of a test designed to evaluate abdominal muscle endurance.

Methods: This study included 21 healthy adults (10 men and 11 women) aged 23.2 ± 3.3 years. Participants recruited from a chiropractic institution performed two fatiguing protocols (with a lordotic posture or free of instructions), each immediately preceded and followed by a maximum voluntary contraction. Force data and surface electromyography of six muscles were recorded. The influence of posture on endurance time as well as the effect of posture on MedF/time slopes for each individual muscle throughout the first four 30-second time segments was assessed.

Results: Mean time until exhaustion was 261.3 ± 149.8 seconds for the lordotic condition and 358.8 ± 206.4 seconds for the free condition. The lordotic condition induced significantly more fatigue than the free condition in three muscles during the first 30 seconds. However, both conditions induced similar levels of fatigue for the following 30 seconds. After the first 60 seconds, no significant differences in fatigability were noted between the two experimental conditions.

Conclusion: For the subjects studied, lumbar lordosis had a significant influence on trunk muscle fatigue during abdominal muscle endurance assessment. Specifically targeting the abdominal muscles during an endurance task remains a challenge.

JMPT abstracts appear in DC with permission from the journal. Due to space restrictions, we cannot always print all abstracts from a given issue. Visit www.journals.elsevierhealth.com/periodicals/ymmt for access to the complete March-April 2011 issue of JMPT.


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