1. A Randomized Trial Comparing Interventions in Patients with Lumber Posterior Derangement. Author: Schenk. Journal of Manual & Manipulative Therapy, Volume 11, Number 2, 2003
Purpose:
Compare joint mobilization and McKenzie Extension Exercises among pts. with LBP and having lumbar posterior derangement according to the Lumbar Spine Index.
Methods:
Subjects randomly assigned to groups. Extension exercise(15) and Joint mobilization(10).
3 physical therapy visits including postural correction, treadmill walking, and either therapeutic exercise or mobilization.
Extension exercise group: Included repetitions of lumbar extension or lumbar extension with the hips offset(5 sets of 10 repetitions).
Joint mobilization group: 5 sets of 10 repetitions of passive mobilization to the spinal segments.

2. Results: Conclusions:
Both groups showed decrease in pain, but extension exercise group had a significantly greater decrease( exercise ; mobilization ) Function: Exercise 9.1 decrease and mobilization 6.2 decrease
Conclusions:
Extension exercise therapy is more effective than joint mobilization in relieving pain and improving function in patients with lumbar posterior derangement.

3. Critique of Study Not a large enough sample size
Group sizes were not the same
No control group included in study
Limited to lumbar posterior derangement
Relatively short treatment period.

4. The McKenzie method compared with manipulation when used adjunctive to information/advice in LBP patients presenting with centralization or peripheralization. SPINE Volume 36, Number 24, pp 1999–2010 ©2011, Lippincott Williams & Wilkins
Purpose:
To compare the effects of the McKenzie method performed by certified therapists with spinal manipulation performed by chiropractors when used with information and advice.
Methods:
350 patients suffering from low back pain for more than 6 weeks who presented with centralization or peripheralization of symptoms with or without signs of nerve root involvement, were included in the trial.
Main outcome: number of patients with treatment success defined as a reduction of at least 5 points on the Roland Morris Questionnaire(self-assessed rater for disability caused my LBP)
Secondary outcomes: reduction in disability and pain, global perceived effect, general health, mental health, lost work time, and medical care utilization.
Maximum of 15 treatments over 12 weeks.

5. Results: Conclusions:
Both groups showed meaningful improvements. At 2 months follow-up, the McKenzie treatment was superior to manipulation with respect to the number of patients who reported success after treatment(71% to 59%)
Difference of 13% in the number of reported global perceived effects
Conclusions:
The McKenzie method is slightly more effective than manipulation when used adjunctive to information/advice.

6. Critique of Study
Results were not very conclusive as to which method was more effective.
No control group used
Very recent

7. Does it matter which exercise
Does it matter which exercise? A randomized control trial of exercise for low back pain. Long A, Donelson R, Fung T, Bonavista Physical Therapy, Calgary, Alberta, Canada.
Purpose:
To determine if low back pain groups respond differently to contrasting exercise prescriptions.
Methods:
A total of 312 acute, subacute, and chronic patients, including LBP and sciatica, underwent a standardized mechanical assessment classifying them by their pain response, specifically eliciting either a "directional preference“(an immediate, lasting improvement in pain from performing either repeated lumbar flexion, extension, or sideglide/rotation tests), or no DP. Only DP subjects were randomized to: 1) directional exercises matching their preferred direction (DP), 2) exercises directionally opposite their DP, or 3) nondirectional exercises.
Outcome measures included pain intensity, location, disability, medication use, degree of recovery, depression, and work interference.

8. Results: Conclusions: A DP was requested in 74% (230) of subjects.
One third of both the opposite and non-directionally treated subjects withdrew within 2 weeks because of no improvement or worsening (no matched subject withdrew).
Significantly greater improvements occurred in matched subjects compared with both other treatment groups in every outcome (P values <0.001), including a decrease in medication use.
Conclusions:
Regardless of subjects' direction of preference, the response to contrasting exercise prescriptions was significantly different: exercises matching subjects' DP significantly and rapidly decreased pain and medication use and improved in all other outcomes.

9. Critique of Study Did not include age of subjects
Protocol of direction specific exercises was not included
No long-term follow-up of study results
Study done in 2004.

10. Overall Impressions
Very useful treatment in both an Athletic Training and Physical Therapy clinic setting.
Helps patients with general back pain and disc derangement more than other methods such as joint mobilizations and manipulations.
McKenzie extension exercises are very effective in reducing pain and increasing ROM

11. Bibliography
A Randomized Trial Comparing Interventions in Patients with Lumber Posterior Derangement. Schenk. Journal of Manual & Manipulative Therapy, 2003; Volume 11, Number 2
Does it matter which exercise? A randomized control trial of exercise for low back pain. Long A, Donelson R, Fung T, Bonavista Physical Therapy, Calgary, Alberta, Canada. 2004;29(23):
The McKenzie method compared with manipulation when used adjunctive to information/advice in LBP patients presenting with centralization or peripheralization. Tom Petersen , PT, PhD , Kristian Larsen , PT, PhD , Jan Nordsteen , DC, MPH , et al. SPINE , 2011; Volume 36, Number 24, pp 1999–2010