Running and back pain - a "love-hate relationship"?

Maselli et al (2020) found low overall prevalence (0.7-20.2%) and incidence (0.3-22%) of low back pain in this review of nineteen studies with a good interrater agreement in full-text selection. Most reported risk factors were: Running for more than 6 years; body mass index > 24; above average height; irregular exercise; limited hip mobility(flexion); leg length discrepancy; insufficient mobility of the ischiocrural muscles and lumbar spine.

Maselli et al (2021) investigated the beliefs, knowledge, attitudes, behaviors, and clinical treatment practices of 1218 Italian physiotherapists specializing in orthopedic manipulative physiotherapy (OMPT) in relation to walking and its association with low back pain (LBP). To this end, a cross-sectional online survey was conducted in 2019 in accordance with the Checklist for Reporting Results of Internet E-Surveys (CHERRIES) and the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines.
A substantial cohort of OMPTs working in private clinical practices (n = 845; 69.4%; 95% CI 66.7-71.9) reported that walking was not a relevant risk factor for the occurrence of LBP (n = 806; 66.2%; 95% CI 63.4-68.8). In addition, most participants (n = 679; 55.7%; 95% CI 52.9-58.5) chose a combination of manual therapy techniques and therapeutic exercises to treat runners with LBP.

In another study, Maselli et al. (2021) analyzed 2539 questionnaires from runners. Overall, 22.6% of runners reported pain in the past year. Most participants (77.0%) who reported LBP episodes believed they were not caused by running. No significant correlations (Cramer's V < 0.60) were found between LBP and demographic data, training characteristics, or lifestyle habits.

Thein-Nissenbaum et al (2012) describe the treatment of a female runner with postpartum hip and lower back pain by exercise training using ultrasound biofeedback (USI) in combination with a change in running form. The complaints could be caused by postpartum dysfunction in the lower back and hips due to incomplete recovery of the abdominal muscles and impaired neuromuscular control of the hip and abdominal muscles. The runner underwent dynamic stabilization training of the lumbar spine with USI biofeedback and modification of her running form to reduce the mechanical load. The muscle thickness of the transversus abdominis and oblique internus was measured with USI before the intervention and 7 weeks after completion of the intervention. In addition, 3-dimensional lower extremity joint movements, moments, and forces were calculated during treadmill running.
Results: Patients' pain during running decreased from a constant VAS scale score of 9/10 to an occasional score of 3/10 after treatment. The thickness of the transversus abdominis muscle increased by 6.3% during the abdominal pull-in maneuver and by 27.0% during the abdominal pull-in maneuver with a straight leg raise. Changes were also observed in the internal oblique abdominal muscle. These findings corresponded with improved lumbopelvic control: pelvic obliquity and axial rotation during walking decreased by 38% and 36% respectively. The patient's running workload returned to pre-injury levels (8.1-9.7 km, 3 days per week), with no hip pain and minimal lower back pain, and she successfully achieved her goal of running a half marathon.

Since most gait analyses for low back pain have so far focused on changes in trunk coordination when walking on a treadmill, too little attention has been paid to locomotion on uneven ground and changes in the lower limbs in connection with low back pain. Müller et al (2015) focussed on lower limb motor function in patients with low back pain. They found that both trunk and lower limb movement is affected by chronic, non-specific low back pain. A consistent finding for all gait types and ground unevenness is that patients with chronic non-specific low back pain have less pelvic rotation and unchanged thoracic rotation compared to healthy controls. In addition, trunk rotation decreased in patients with chronic non-specific low back pain only during level and uneven walking, while sagittal trunk tilt increased during striking only during uneven walking compared to healthy controls. In addition to significant changes in the upper body, the knee joint angle at the striking of the foot was elongated in patients with chronic non-specific low back pain during both level walking and uneven walking and running compared to healthy controls. The researchers assume that the movements of the trunk interact with the movements of the lower limbs or vice versa. We therefore recommend that further research into low back pain should take into account both the movements of the trunk (especially the pelvis) and the lower limbs (especially the knees).
PhysioNovo note: a weakened function of the hip joint fundamentally affects the motor function of the pelvis and the leg, including the knee and ankle. One possible explanation may be that more flexion in the hip (and therefore more flexion in the knee) increases the load on it through leverage.

In a randomized single-blind study, Cai et al. (2017) compared the treatment effect of lower limb (LL) exercises with conventional lumbar extensor (LE) and lumbar stabilization (LS) exercises in recreational runners with chronic low back pain (cLBP), as there is currently no specific protocol for the treatment of runners with cLBP.
Eighty-four recreational runners with cLBP were divided into three exercise groups (LL, LE, LS) for an 8-week intervention. Outcome measures included self-assessed pain and running ability, LL strength, back muscle function, and running stride. Participants were assessed pre-intervention, mid-intervention, and at the end of the intervention; selected outcomes were also followed up at 3 and 6 months. A generalized estimating equation was used to examine the interaction between group and time.
The LL group showed a greater increase in stride length. All three groups improved their back muscle function in a similar way.
LL exercise therapy could be a new option for the treatment of CLPB as it shows superior effects in improving walking ability, knee extension strength, and walking behavior.
Remark PhysioNovo: Also in this case the function of the hip joint could play a crucial role in the development of back pain. Treatment of the leg (especially the hip joint) could then be an effective option for the treatment of back pain in runners.

Simonet et al (2020) investigated how non-specific chronic low back pain (NSLBP) affects the lumbar lordosis angle (LLW) during repetitive activities such as walking or running.
Thirteen patients with NSLBP and 20 healthy, pain-free controls were enrolled in the study and underwent a whole-body movement analysis that included various activities of daily living such as standing, walking, and running. Patients with NSLBP showed reduced mean LLWs during standing, and walking and a tendency towards lower LLW ROM during walking. Analysis of the continuous data revealed that the largest group differences occurred at 25% and 70% of walking and at 25% and 75% of running. In addition, the patients showed an inverse movement pattern during walking, where the LLA increased rather than decreased after foot touchdown. This study provides initial evidence that NSLBP may influence LLWs during walking and running. These results can be used as a basis for future large-scale studies with hypothesis testing.
PhysioNovo comment: reduced average LLWs during standing, and walking and a tendency towards lower LLW ROM during walking can be explained as compensatory motor function to unload the SI joints and LSGs. The opposite pattern during running can be explained by insufficient extension of the hip due to arthromyogenic inhibition of the hip extensors, i.e. due to hip joint dysfunction.

My recently published book "Trainingskonzeption für Patienten mit Rückenschmerz -PhysioNovo - Angewandte Rehabilitation und Sporttherapie" contains further interesting studies on the subject of running and back pain. It also thoroughly explains how an (already minor) dysfunction of the hip can lead to insufficient motor activity of the leg, pelvis, and lumbar spine resulting in back pain.