152 / The Journal of Manual & Manipulative Therapy, 2005 L ow back pain (LBP) is a costly and troubling phenom- enon, affecting 60% to 80% of Americans within their lifetime 1,2 . The one-year prevalence of acute LBP has been estimated to exceed 60% 3 , causing nearly 5% of Ameri- cans to lose work and/or require medical intervention 4 . Historically, physical therapist-administered therapeutic exercise has played an essential role in management of LBP 5,6 , a disorder that contributes to 40% of Worker’s Compensation-related therapy visits 7 . Physical Therapy Exercise Intervention Based on Classification Using the Patient Response Method: A Systematic Review of the Literature Address all correspondence and request for reprints to: Chad Cook Assistant Clinical Professor Duke University DUMC 3907 Durham, North Carolina 27710 chad.cook@duke.edu Abstract: I t has been suggested that inclusion into a study that categorizes patients in mutually exclusive, clinometric classifications should improve the outcome of an exercise based randomized clinical trial. This review examined the evidence regarding the effective- ness of physical therapist-directed therapeutic exercises when patients were classified using the patient response method. This systematic literature review restricted article inclusion to English-only articles that classified homogenous samples of low back pain patients us- ing the patient response based method, demonstrated physical therapist-directed exercise interventions, and used specific outcome criteria for assessment of patient improvement. The PEDro scale was used to rate the methodological quality of the studies. Of 82 articles reviewed only 5 articles were accepted. All 5 met the PEDro standards for a high-quality study. Of the 5 articles, 4 demonstrated that physical therapy exercise intervention based on the patient response method of classification were significantly better than the pragmatic control comparisons; the remaining article indicated that exercise was less effective than manipulation. There appears to be a trend toward positive outcomes with physical therapy exercise intervention in trials restricted to the patient response method of classification; however, few studies have investigated this phenomenon. Key Words: Physical Therapy, Exercise Therapy, Patient Response-Based Classification, PEDro, Low Back Pain, Systematic Review. Chad Cook, PT, PhD, MBA, OCS Eric J. Hegedus, PT, DPT, OCS Kevin Ramey, MS, PT Although the prevalence of LBP is compelling, there is a notable lack of evidence to support exercise interven- tions used by physical therapists. Recently, Van Tulder, Furlan, Bombardier et al 8 and Van Tulder, Malmivaara, Esmail et al 9 of the Cochrane Collaboration Back Review Group suggested that evidence to support one exercise approach for LBP has yet to be demonstrated beyond doubt. Findings for selected interventions such as flexion or extension exercises 8 , spinal traction 3 , mobilization and manipulation, and variants of physical agents 10 lack definitive benefit. Several reasons have been suggested as to why past studies have failed to demonstrate significant findings. First, in most studies, heterogenous low back conditions were lumped into one singular group or classified into time-based categories of “acute” (0-7 days) “sub-acute” (7 days to 7 weeks) or “chronic” (greater than 7 weeks) LBP 11-37 . Second, a good number of studies failed to The Journal of Manual & Manipulative Therapy Vol. 13 No. 3 (2005), 152 - 162