Table 3.

General characteristics of the included studies.

Articles	Sample (drop out)	Intervention	Duration, frequency and intensity of intervention	Outcomes	Evaluation/reassessment	Results
Beneck et al.18	98(21) A:51(6) B:47(15)	A: education & exercise (lumbar extensor strength, endurance training, trunk and lower extremity training) B: education	3 times a week for 12 weeks	-Quality of life (SF-36)	-At baseline (4–6 weeks postoperatively) -After the therapeutic intervention (12 weeks)	- Statistically significant improvement on SF-36 role physical and SF-36 bodily pain in group A comparison to group B.
Jentoft et al.21	70 A:33 B:37	A: Information (advise, education) & standard post-operative mobilization. Exercise program (hospital & home): mobility, strength, stretching B: Information (advise, education) & standard post-operative mobilization.	For 12 weeks 2-6 treatments, 10–30′, 7 exercises, 8–10 repetitions, gradually increase, twice a day (hospital) and 11 exercises (home)	-Pain: back/hip pain, leg pain (NPRS) -Disability (ODI)	-At baseline - 6–8 weeks after surgery −12 months after surgery	-Statistically significant improvement in leg pain in both groups after 12 months. Group A had also statistically significant improvement between 6 and 8 weeks and 12 months. There was not a statistically significant improvement for back/hip pain in both groups. Between both groups group A had statistically significant better results after 12 months for leg pain. -Statistically significant improvement in disability in both groups after 12 months. Group A had also statistically significant improvement between 6 and 8 weeks and 12 months Between both groups, group A had statistically significant better results after 12 months.
Ju et al.1	14 A:7 B:7	A: Medx lumbar extension program and progressive resistance exercise PRE (torso flexion, hip extension, torso rotation, leg extension, seated leg curl, leg press, abdominal press, overhead press) Β: no exercise rehabilitation program	70′ 3 times a week for 12 weeks Medx: 40–50% maximal isometric strength. Intensity gradually increased by increasing the weight by 5–10% PRE: exercise intensity 40–50% of the participants’ one repetition maximum, 18–20 repetitions per set	- Pain: back pain, night pain, exercise pain, handicap (VAS) -Strength (Med, USA)	-At baseline -After the therapeutic intervention for group A (12 weeks) -After resting for weeks for group B	-Statistically significant improvements in all four types of pain in group A. Group B did not show any statistically significant improvements. -Group A showed statistically significant improvement in strength, whereas group B did not.
Kim et al.17	34(4) A:11(1) B:12(2) C:11(1)	A: After 6 weeks of rest the participants followed a progressive resistance exercise (stretching, aerobic exercise, lumbar extension training with the MedX machine) Β: After 6 weeks of rest the participants followed an aquatic backward locomotion exercise (stretching and water exercises) C: After 6 weeks of rest the participants were instructed to maintain everyday activities without any intensive training exercise	60′ After 6 weeks of rest, exercise program was performed 2 times a week for 12 weeks followed by a period of detraining and then retraining Stretching: 40% HRmax A: aerobic exercise 40–60% HRmax, lumbar extension training 2 sets 15–20 repetitions 50–60% 1 RM B: ranging between 40 and 70% HRmax	-Strength: isometric lumbar extension strength (MedX)	-At baseline (before surgery) −6 weeks after surgery −12 weeks after surgery (first 6th week exercise program) −18 weeks after surgery (second 6th week exercise program) -after detraining -after retraining	-Group A and B had greater increases in strength after the first 6th week exercise program in comparison to group C. Statistically significant improvement was shown after the second 6th week exercise in group A and in group B. After the detraining period in both A and B group, the lumbar extension strength decreased similar and became about the same with group C. After the retraining period, group A an B had statistically significant better strength than group C.
Ogutluler Ozkara et al.19	30 A:15 Β:15	Α: instructions (lying, standing, sitting, walking) and an exercise program (strengthening, stretching, passive-active movement, mobilization) Β: instructions (lying, standing, sitting, walking)	3 times a week, for 12 weeks. 2 sets of each exercise, first week 10 repetitions and after the first week 5–10 repetitions	-Pain (VAS) -Disability (ODI) -Quality of life (SF-360 -Resume to work	- At baseline -Reassessment at 6 weeks - After the therapeutic intervention (12 weeks)	-Statistically significant improvement on VAS in both groups. Between both groups group A had statistically significant better results. -Statistically significant improvement on ODI in both groups. Between both groups, group A had statistically significant better results. -For group A there was statistically significant improvement in SF-36 virality and SF-36 emotional role, whereas in group B only for SF- virality. Between both groups, group A had statistically significant better results in physical functioning of the SF-36, including body pain and social functioning sub-parameters. -Between both groups there was not a statistically significant difference for the term of returning to normal life.
Oosterhuis et al.16	173 Α:92(12) Β:77(7)	Α: 1–2 days postoperative care. Advice and instructions for transfers and performing daily living activities. At discharge they were given a booklet providing advice and suggestions for exercises. The therapist focused his treatment on the ability for personal care activities. Exercises were taught with gradually increasing intensity. Β:1–2 days postoperative care. Advice and instructions for transfers and performing daily living activities. At discharge they were given a booklet providing advice and suggestions for exercises	30′ per week 1 or 2 times a week for 6–8 weeks	-Pain: leg pain, back pain (NRS) -Disability (ODI) -quality of life: general physical and mental health (SF-12)	-At baseline -After 3,6,9,12 and 26 weeks	There was an improvement in all of these variables in both groups but they were not characterized as statistically significant. Between both groups the results were not statistically significant different.
Rushton et al.20	59 A:29(12) Β:30(11)	Α:Physiotherapy & leaflet: education, advice, mobility exercises, core stability exercises, progressive approach to exercise Β:Patient leaflet	For 8 weeks, 8 physiotherapy sessions	-Pain: beck pain, leg pain (VAS) -Disability (RMDQ) -quality of life (EQ-5D) -return to work/function	-At baseline (4 weeks after surgery) -After the therapeutic intervention (12 weeks after surgery) -Follow-up assessment (26 weeks after surgery)	-In all the variables there was an improvement in both groups but it wasn’t characterized as statistically significant.