Table 2 Characteristics of included systematic reviews and their included randomized controlled trials

Koes 1991 [49]

To determine the quality of RCTs of ET for back pain.

MEDLINE 1966–1990

16 (4)

Farrell 1982 [50] (n = 48) Australia, Waterworth 1985 [51] (n = 108) New Zeeland, Gilbert 1985/Evans 1987 [52] (n = 252) Canada, Stankovic 1990/1995 [53] (n = 100) Sweden

Back pain. aLBP without neurological sign. Age: not located. Female: not located [54]. Mechanical aLBP. Age: not located. Female: not located [55]. aLBP ± referred pain. Age: mean 40 (SD 15). Female 49% [51]. aLBP ± referred pain. Age: 18-61. Female: 23 [56].

Physiotherapy should include individual ET provided by physiotherapists. Isometric flexion abdominal exercise with ergonomic instructions and microwave diathermy [54]. Flexion and extension exercise with ergonomic advice [55].Isometric flexion exercise and education [51]. McK [56].

Not defined in PICO of SR. Manipulation and mobilization [54]. NSAID with ergonomic advice or manipulation with ergonomic advice [55].Bed rest, no intervention [51].Mini back school [56].

Not defined in PICO of SR. Time to recovery, ROM [54]. Pain, mobility, overall improvement, time off work, cost [55]. Pain, mobility, ADL [51]. Pain, ROM, recurrence, return to work, sick leave, patients’ ability to self-help [56].

Faas 1996 [57]

To determine from recently published trials the efficacy of exercises in patients with acute, subacute, or chronic back pain.

MEDLINE 1991 to first quarter 1995.

11 (4)

Delitto 1993 [58] (n = 24) USA, Faas 1993/1995 [59] (n = 473) Netherland,Malmivaara 1995 [60] (n = 186) Finland,Stankovic 1990/1995 [53]

Patients with back pain. LBP ± referred pain. Age: 14–50 years. Female 42% [61]. LBP ± referred pain. Age: 16-65. Female: 43% [62]. LBP ± referred pain. Age: adults, mean 40.5. Female: 68% [52]. See above [56].

ET. McK and mobilization [61]. Flexion exercise⁶⁸. Extension exercise [52]. McK [56].

Not defined in PICO of SR. Flexion exercise [61]. Placebo ultrasound, usual care (analgesic on demand) [62]. Bed rest for 2 days or continue ADL without bedrest [52]. Mini back school [56].

Not defined in PICO of SR. Disability [61], pain, disability, recurrence, ADL, sick leave [62]. Pain, disability, patient satisfaction, ROM, QoL, ability to work, Costs⁸². Recurrence, sick leave⁸¹.

van Tulder 1997 [63]

To assess the effectiveness of the most common conservative types of treatment for patients with acute and chronic LBP.

MEDLINE 1966-, EMBASE 1908- and PsycLIT 1984- Sep 1995.

150 (7)

Farrell 1982 [50], Gilbert 1985/ Evans 1987 [52]Waterworth 1985 [51], Stankovic 1990/1995 [53], Delitto 1993 [58], Faas 1993/1995 [59],Malmivaara 1995 [60].

Acute (0–6 weeks) or chronic LBP. See above [51, 52, 54,55,56, 61, 62].

Common conservative treatments. See above [51, 52, 54,55,56, 61, 62].

Not defined in PICO of SR. See above [51, 52, 54,55,56, 61, 62].

Pain intensity, overall improvement and functional status. See above [51, 52, 54,55,56, 61, 62].

van Tulder 2000 [64]

To determine whether ET is more effective than reference treatments for nonspecific LBP, and to determine which type of exercise is most effective.

MEDLINE 1966- Apr 1999. EMBASE 1988- Sep 1998.PsycLIT 1984–Apr 1999.Cochrane Library Issue 1 1999.

39 (10)

Farrell 1982 [50], Gilbert 1985/Evans 1987 [52], Waterworth 1985 [51], Stankovic 1990/1995 [53], Delitto 1993 [58], Faas 1993/1995 [59],Malmivaara 1995 [60], Cherkin 1998 [65] (n = 321) Canada, Seferlis 1998 [66] (n = 180) Sweden, Underwood 1998 [67] (n = 75) United Kingdom.

Adults 18 to 65 years, non-specific LBP = pain located below the scapulas and above the cleft of the buttocks, ± radiation to the legs, including nerve root pain or sciatica. See above [53, 63, 64, 67,68,69,70]. LBP severe neurological sign and sciatica excluded. Age 20–64. Female 48% [71]. LBP ± sciatica requiring sick leave. Age: 19–64. Female: 47 [60]. LBP ± referred pain. Age: 16–70. Female: 40% [72].

Specific back exercises as well as abdominal, flexion, extension, static, dynamic, strengthening, stretching or aerobic exercises, if they were prescribed or performed in the treatment of LBP. Additional physicaltreatment methods were allowed. See above [51, 52, 54,55,56, 61, 62]. McK [71]. Intensive training program [60]. McK + advice [72].

Not defined in PICO of SR. See above [53, 63, 64, 67,68,69,70]. Manipulation or educational booklet [11].Manual therapy or General practice [60].Advice with usual care [72].

Pain, global measure, back pain-specific functional status, return to work, ROM, generic functional status, medication use and side effects.See above [51, 52, 54,55,56, 61, 62]. Global improvement, disability, cost of care, patient satisfaction, recurrence, use of care [71]. Pain, disability, ROM recurrence, patient satisfaction, days of work [60]. Pain, disability, recurrence [72].

Ferreira 2003 [73]

To assess the efficacy of manual therapy techniques in the treatment of nonspecific LBP of less than 3 months duration.

MEDLINE 1966-, EMBASE 1974-, CINAHL 1982- Mar 2001.PEDro- Jul 2002.

27 (4)

Delitto 1993 [58], Erhard 1994 [55] (n = 25) USA,Cherkin 1998 [65], Seferlis 1998 [66].

Adults with nonspecific LBP of less than 3 months duration, as reported by the median or mean. See above [60, 61, 71]. LBP ± referred pain. Age mean 44 (SD 15). Female 38% [50].

SMT: high-velocity, low amplitude thrust, joint manipulation; low-velocity, small- or large-amplitude joint mobilization; manual traction; or craniosacraltherapy. See above [60, 61, 71]. McK [50].

Not defined in PICO of SR. See above [5, 60, 71]. Manipulation + flexion-extension exercise [50] ⁶.

Disability, pain, QoL, adverse events, return to work, global perceived effect or patient satisfaction with therapy. See above [60, 61, 71]. Disability [50].

Clare 2004 [70]

To investigate the efficacy of the McK method of management of non- specific spinal pain. Specific questions: What is the comparative efficacy of McK therapy in relation to inactive treatment (placebo or sham) or no treatment? What is the comparative efficacy of McK treatment in relation to other standard therapies?

MEDLINE, EMBASE, DARE, CINAHL, PEDro, CENTRAL, CDSR to Sep 2003.

6 (3)

Roberts 1990 [54] (n = 179) United Kingdom,Cherkin 1998 [65], Schenk 2003 [74] (n = 25) USA.

Subjects with non-specific LBP or neck pain ± radiation. Any duration of symptoms. See above [71]. LBP ± referred pain. Age: mean 35. Female: 37% [27]. LBP of disc origin ± neurological signs. Age: 21–76. Female: 60% [66].

Specifies individualized treatment according to the McK principles; if a co-intervention then excluded. See above [71]. McK [27]. McK [66].

No treatment, sham treatment, or another treatment. See above [71]. NSAID [27]. Mobilzation [66].

Pain, disability, QoL, work status, global perceived effect, medication use, medical visits, or recurrence. See above [71]. Pain, disability, recurrence, days of work [27]. Pain, disability [66].

Hayden 2005c [69]

To assess the effectiveness of ET for reducing pain and disability in adults with non-specific acute, subacute and chronic LBP compared to no treatment, placebo, or other conservative treatments.

CENTRAL Issue 3 2004, MEDLINE, EMBASE to Oct 2004, PsychInfo, CINAHL 1999–Oct 2004.

61 (9)

Farrell 1982 [50], Gilbert 1985/Evans 1987 [52], Stankovic 1990/1995 [53], Delitto 1993 [58], Faas 1993/1995 [59], Malmivaara 1995 [60], Hides 1996/2001 [72] (n = 41) Australia, Seferlis 1998 [66], Chok 1999 [75] (n = 66) Singapore.

Adults, acute (0–6 weeks), subacute or chronic non-specific LBP. See above [51, 52, 54, 56, 61, 62]. First episode of unilateral, mechanical LBP ± radiating pain. Age: 17–45. Female: 56% [53]. LBP with or without leg pain. Age: 21–54. Female: 24% [58].

ET. See above [51, 52, 54, 56, 61, 62].Multifidus isometric retraining [53]. Endurance program [58].

No treatment, placebo, other conservative therapy or another exercise group. See above [51, 52, 54, 56, 61, 62]. Advice on bed rest and absence from work with prescription of analgesic [53]. Non- exercise, hot pack to use at home [58].

Pain intensity, physical functioning, global improvement and return to work/absenteeism. See above [51, 52, 54, 56, 61, 62]. Pain, disability, ROM, ADL, Muscle CSA [53]. Pain, disability, trunk extensor endurance [58].

Ferreira 2006 [68]

To conduct a SR of the effects of specific SE for spinal or pelvic pain when this intervention was compared with placebo, no treatment, another active treatment, or when specific SE was added as a supplement to other interventions.

MEDLINE 1966-, EMBASE 1974-, CINAHL 1982- and PEDro- March 2004.

12 (1)

Hides 1996/2001 [72]

Adults with symptoms in the cervical, thoracic, low back, or pelvic area. Symptoms could be referred distal. See above [53].

One group received specific SE or exercise aimed at activating, training, or restoring the stabilization function of specific muscles of the spine and pelvis in isolation or in conjunction with other therapies. See above [53].

Not defined in PICO of SR. See above [53].

Disability, pain, return to work, no. of episodes, global perceived effect, or health-related quality of life. See above [53] + Recurrence.

Machado 2006 [76]

To evaluate whether the McK method is more effective than other reference treatments for acute or chronic nonspecific LBP.

MEDLINE, EMBASE, PEDro, and LILACS to Aug 2003.

11 (5)

Stankovic 1990/1995 [53], Dettori 1995 [61] (n = 149) Germany, Malmivaara 1995 [60], Cherkin 1998 [65]. Underwood 1998 [67].

Non-specific LBP of any duration. LBP = pain between the lower rib cage and gluteal folds, ± radiation. See above [52, 56, 71, 72]. LBP ± referred pain. Mean age 29. Female 20% [77].

RCTs with McK method or a synonym (McK therapy, Mechanical Diagnosis and Therapy) or intervention reflecting McK principles. Co-interventions were allowed. See above [52, 56, 71, 72]. McK + ice pack [77].

Not defined in PICO of SR. See above [52, 56, 71, 72]. Flexion exercise or Ice pack [20].

Pain, disability, QoL, return to work/ sick leave, or recurrence. See above [52, 56, 71, 72]. Pain, disability, return to work, recurrence, ROM, SLR [77].

Rackwitz 2006 [28]

To evaluate the effectiveness of segmental SE for acute, subacute and chronic LBP with regard to pain, recurrence of pain, disability and return to work.

MEDLINE 1988- and EMBASE 1989- Dec 2004.

7 (1)

Hides 1996/2001 [72].

Adults > 18 years and take part in a program treating acute, subacute or chronic LBP ± sciatica. See above [53].

The intervention group has to have received segmental SE at least as part of the treatment. See above [53].

Not defined in PICO of SR. See above [53].

Pain, recurrence, disability, and return to work. See above [53].

Hauggaard 2007 [78]

To evaluate the effects of specific spinal SE in patients with LBP, and to assess the methodological quality and level of evidence of the studies.

PubMed 1985- Oct 2005.PEDro 1985- Dec 2006.

10 (1)

Hides 1996/2001 [72].

Acute, sub-acute, or chronic LBP. See above [53].

Intervention containing specific spinal SE including co-contraction of multifidus muscles and transversus abdominis muscles. See above [53].

Not defined in PICO of SR. See above [53].

Specific functional questionnaires and/or generic questionnaires and/or pain rating. See above [53].

Keller 2007 [62]

To synthesize the results of RCTs for common LBP treatments comparing the interventions to placebo/ sham or no-treatment, to estimate a pooled effect size for each treatment, and compare them with each other.

CENTRAL issue 2 2005.MEDLINE, EMBASE, CINAHL, AMED from the last search in each Cochrane review to Dec 2005.

47 (4)

Faas 1993/1995 [59], Malmivaara 1995 [60], Chok 1999 [75] Mayer 2005 [79] (n = 100), USA.

Acute and subacute/chronic LBP. Acute LBP = duration of pain less than 6 weeks. See above [52, 58, 62]. LBP ± referred pain but no neurological signs. Mean age 31.2 (SD 10.6). Female: 71% [67].

Non-surgical treatments, including exercise, manipulation, behavioral treatment, NSAIDs, acupuncture. See above [52, 58, 62].

Placebo, sham treatments, no treatment, waiting list. See above [52, 58, 62].

Self-reported pain intensity and physical functioning. See above [52, 58, 62].

Liddle 2007 [80]

To examine the evidence for the use of advice in management of LBP. Secondary objectives included assessment of the effectiveness of interventions in relation to LBP phase.

MEDLINE, AMED, CINAHL, PsycInfo, DARE, andCENTRAL 1985 to Sept 2004.

39 (7)

Gilbert 1985/Evans 1987 [52], Stankovic 1990/1995 [53], Faas 1993 [59], Malmivaara 1995 [60], Cherkin 1998 [65]

Adults, 16 and 79 years with acute (0–4 weeks), subacute (4–12 weeks), or chronic (4–12 weeks) LBP. See above [51, 52, 56, 62, 71].

Advice, either as main intervention or as an adjunct to exercise. See above [51, 52, 56, 62, 71].

Placebo ultrasound, Mini back school. See above [51, 52, 56, 62, 71].

Back-specific function, generic health status, pain, work disability, patient satisfaction, adverse effects. See above [51, 52, 56, 62, 71].

Engers 2008c [81]

To determine whether individual patient education is effective for pain, global improvement, functioning and return-to-work in the treatment of non-specific LBP, and to determine which type of education is most effective.

MEDLINE 1966-, EMBASE 1988-, CINAHL 1982- and PsycINFO 1984 to July 2006. CENTRAL 2006 Issue 2.

24 (2)

Cherkin 1998 [65], Mayer 2005 [79].

Adults > 16 years with acute, subacute or chronic non-specific LBP. See above [67, 71]

Individual patient education. See above [67, 71]

No intervention, non-educational interventions or another type of individual patient education. See above [67, 71]

Pain intensity, global measure, back pain specific functional status, return-to-work, generic functional status, ADL. See above [67, 71]

May 2008 [82]

To evaluate the effectiveness of SE in the treatment of pain and dysfunction from LBP.

MEDLINE 1966-, CINAHL 1982-, AMED 1985- and PEDro to Oct 2006. CENTRAL 2006 Issue 1.

18 (2)

Hides 1996/2001 [72], Brennan 2001 [83] (n = 123) USA.

Adults > 18 years with LBP, any duration. See above [53].LBP ± referred pain in legs. No neurological signs. Age: mean 37.7 (SD 10.7). Female: 45% [74].

One intervention arm primarily used SE = facilitation of abdominal and/or lumbar extensor muscles initially at low levels of contraction and progressing to integration into everyday activities. See above [53]. SE [74].

An alternative intervention. See above [53]. Manipulation or DP exercises [74].

Pain and/or functional disability. See above [53]. Disability [74].

Ferreira 2009 [84]

To investigate the efficacy of motor control exercises for low-back and pelvic pain.

Cochrane, MEDLINE, PEDro to 2009.

8 (1)

Hides 1996/2001 [72].

Studies examining MCE in isolation or with other treatment. See above [53].

MCE according to Richardson et Jull. See above [53].

Not defined in SR. See above [53].

Pain and disability. See above [53].

Choi 2010c [85]

To investigate the effectiveness of exercises for preventing new episodes of LBP or LBP-associated disability.

CENTRAL- 2009, issue 3, MEDLINE, EMBASE, CINAHL to July 2009.

9 (4)

Stankovic 1990/1995 [53], Faas 1993/1995 [59], Cherkin 1998 [65], Hides/1996 2001 [72].

Adults > 18, who currently had, or had ever had at least one prior episode of non-specific LBP = defined as LBP below the costal margin and above the inferior gluteal folds ± leg pain, that has no specific underlying pathology. See above [53, 56, 62, 71].

Exercise aimed at the prevention of recurrences of LBP, divided into post-treatment and treatment. Post-treatment = exercise provided after regular treatment for an episode of back pain had been finished with the explicit aim to prevent new occurrences of back pain. Treatment = exercise for a current episode of back pain with the aim to also prevent new episodes of back pain. See above [53, 56, 62, 71].

Not defined in PICO of SR. See above [53, 56, 62, 71].

Recurrences (frequency or duration of new episodes of LBP) or the time to a LBP recurrence. See above [53, 56, 62, 71].

Dahm 2010c [86]

To determine the effects of advice to rest in bed or stay active for patients with LBP or sciatica.

Cochrane Back Review Register to May 2009. CENTRAL 2009 issue 2. MEDLINE, EMBASE, SPORT and SCISEARCH 1998- May 2009.

10 (2)

Gilbert 1985/Evans 1987 [52], Malmivaara 1995 [60]

Adults 16 to 80 years of age, acute (0–6 weeks) LBP=area bounded by the lowest palpable ribs superiorly and the gluteal folds inferiorly or exacerbations of chronic pain lasting less than 6 weeks. See above [51, 52].

One group of subjects was advised to rest in bed (instructions to stay in bed for at least two days) and at least one group was not. Or at least one group of subjects was advised to stay active (instructions to stay as active as possible and continue normal daily activities) and at least one group was not. See above [51, 52].

Comparison were randomized to shorter or longer periods of bed rest or to receive the advice to stay active in different ways. See above [51, 52].

Pain, back-specific functional status, overall disability, quality of life and adverse events. See above [51, 52].

Kriese 2010 [71]

To evaluate the effectiveness of Segmental SE for acute, subacute, chronic and recurrent LBP.

PubMed Nov 2008–March 2009

17 (1)

Hides 1996/2001 [72].

Acute, subacute, chronic or recurrent LBP. SR in German with abstract in English. See above [53].

Segmental SE. See above [53].

Other forms of therapy. See above [53].

Not defined in PICO of SR. See above [53].

Dunsford 2011 [87]

To summarize current research evidence for DP exercises, as applied under the McK method, in the treatment of mechanical LBP.

CINAHL, AMED, MEDLINE, PubMed, EMBASE, Cochrane Library, Google Scholar, PEDro, 1995- Feb 2010.

4 (3)

Cherkin 1998 [65], Schenk 2003 [74], Mayer 2005 [79]

Adults > 18 years, mechanical LBP of any duration with a DP. See above [66, 67, 71].

McK-based, DP exercises. See above [66, 67, 71].

All types of comparison included (either control, other conservative or surgical based intervention). See above [66, 67, 71].

Pain and functional outcomes were considered. See above [66, 67, 71].

Rubinstein 2012c [23]

To examine the effectiveness of SMT for aLBP on primary and secondary outcomes as compared to inert interventions, sham, and all other treatments.

CENTRAL, MEDLINE, EMBASE,CINAHL, PEDro, and Index Chiropractic 2000 to July 2012.

20 (4)

Farrell 1982 [50], Cherkin 1998 [65], Seferlis 1998 [66], Brennan 2001 [83]

Adults > 18 years of age with a mean duration of LBP < 6 weeks ± radiating pain. See above [54, 60, 71, 74].

Studies were included for consideration if the study design used indicated that the observed differences were due to the unique contribution of SMT. See above [54, 60, 71, 74].

Inert interventions, sham SMT, all other therapies or another SMT technique. See above [54, 60, 71, 74].

Pain, back-pain specific functional status, global improvement or perceived recovery, perceived health status or QoL and Return-to-work. See above [54, 60, 71, 74].

Surkitt 2012 [88]

To determine the efficacy of treatment using the principles of DP Management for people with LBP and a DP.

MEDLINE 1950-, EMBASE 1980-, CENTRAL, CINAHL 1982- and PEDro to Jan 2010.

6 (2)

Schenk 2003 [74], Brennan 2001 [83]

Trials involving male and female participants aged > 18 with LBP ± leg symptoms with a DP were included. See above [66, 74].

Trials evaluating the effect of DP management on LBP with a DP. Trials were included where DP management was used with co-interventions. See above [66, 74].

No therapy, placebo, or other conservative treatments. See above [66, 74].

Measures of pain intensity, low back-specific function, and work participation. See above [66, 74].

Macedo 2016c [17]

To evaluate the effectiveness of motor control exercise for patients with acute non- specific LBP.

MEDLINE, EMBASE, CENTRAL, AMED to March 2015.MEDLINE In-Process and Non-Indexed Citations, CINAHL, SportDiscus, PEDro, LILACS, PubMed to April 2015.

3 (3)

Hides 1996/2001 [72], Brennan 2001 [83]Aluko 2003 [77] (n = 33), United Kingdom.

Adults, mean age 36 (31–38). Trials with a mixed population in relation to type and duration of back pain only if separate data were provided for each group, or if the acute/subacute population corresponded to the majority of included participants (> 75%). See above [53, 74]. LBP. Age: mean 36 (SD 9.4). Female: 85% [65].

Trials with MCE.See above [53, 74].Core SE and eight specific exercises for stabilization of the transversus abdominis (TrA) and the lumbar multifidus (LM) [65].

No treatment, another treatment or MCE as a supplement to other interventions. See above [53, 74]. Core SE (specific and global trunk exercises) [65].

Pain intensity, disability, function, quality of life, adverse events and recurrence. See above [53, 74]. Pain, Disability, ROM acceleration [65].

Lam 2018 [89]

To determine the effectiveness of MDT provided by trained therapists compared to that of different types of comparator interventions for improving pain and disability in patients with acute and chronic LBP separately.

MEDLINE, EMBASE, CINAHL, CDSR PsycINFO, and PEDro. Three searches: Nov, 2015, May 2016 and Sep 2017.

17 (4)

Cherkin 1998 [65], Schenk 2003 [74], Machado 2010 [27] (n = 146), Australia, Schenk 2012 [56] (n = 31), USA.

Patients with LBP. Only trials in which therapists were MDT trained. See above [66, 71]. aLBP, pain between the 12th rib and buttock crease, ± leg pain, < 6 weeks in duration, preceded by at least 4 weeks without LBP in which the patient did not consult a health care practitioner, 18–80 years of age. Female 50% [59]. LBP, at least 3 of 5 selection criteria from clinical prediction rules, ≥ 18 years of age mean symptom duration, 15 days. Female 61% [75].

Studies in which an MDT classification was not completed prior to the treatment were excluded, as a priori classification is essential for the MDT approach. See above [66, 71]. MDT: first-line care, DP exercises, postural correction and education, Treat Your Own Back book, lumbar roll, home exercise program [59]. MDT: DP exercises, home exercise program [75].

Typical rehabilitation intervention, such as manual therapy, exercise, or education. See above [66, 71]. Education: physician advice and acetaminophen [59]. Manual therapy plus exercise: regional lumbopelvic thrust technique, hand-heel rock range- of-motion exercise [75].

Pain and disability. See above [66, 71]. Pain, disability, and function [59]. Pain and disability [75].

24 SRs published from 1991 to 2018.

Sub-categories in aim: Exercise therapy in 5 SRs, conservative or common treatment in 2 SRs, comparison in 5 SRs, McK in 5 SRs and SE in 7 SRs.

19 databases/registers/Indexes included. Search range from 1908 to Sep 2017.

572 RCTs (88)^a

25 publications based on 21 RCTs, n = 2685. Published from 1982 to 2013.

All RCTs include aLBP with or without referred pain in legs. Female: 47%.

Types of exercise therapy: general exercise therapy, stabilization exercise and McKenzie therapy.

34 different definitions of comparisons

22 different definitions of outcomes