Low back pain is a common condition that occurs in up to 70% of the population in industrialized countries and is the second most common cause of work inability. Physiotherapy is the usual treatment for low back pain. Recent studies showed that combining theory-based psychological methods with physiotherapy can enhance the effectiveness of physiotherapy treatment for people with chronic low back pain.

One promising approach to treating chronic pain is PACT - Physiotherapy informed by Acceptance and Commitment Therapy (ACT), a form of cognitive-behavioral therapy. PACT aims to increase psychological flexibility and focus on improving function rather than reducing pain.

According to several studies, the effects of ACT can be maintained up to 3 years post-treatment, which is essential in a condition such as chronic pain and its typical relapses.

According to self-determination theory (SDT), facilitating an environment of acceptance and autonomy support enhances treatment motivation, thus offering a good interface for applying SDT´s research concepts to ACT interventions.

The primary objective of this study is to investigate the impact of physiotherapists´ autonomy-supportive behavior within PACT on the motivation process in chronic low back pain patients. Other objectives are to evaluate the efficacy of PACT on the functioning and disability due to CLBP, adherence to recommended physical activity, and the acceptance of pain.

This prospective, randomized controlled trial will include 2 treatment groups (PACT treatment group and Usual physiotherapy Care group[UC]) in 1:1 ratio. Participants in the PACT treatment group will undergo a physiotherapy intervention guided by ACT principles.

Participants randomized to UC will receive treatment considered suitable by their treating physiotherapist, including exercises based on the DNS concept and manual therapy.

Regardless of group assignment, all participants will undergo 6 physiotherapy face-to-face interventions lasting 45 minutes, each once a week.

Study outcomes will include measures of treatment motivation, perceived degree of autonomy support within the care settings, functioning, and disability, adherence to recommended physical activity, and acceptance of pain.

While we acknowledge the value of usual physiotherapy care, CLBP is best suited to a biopsychosocial model for care. Further research is needed to understand which underlying processes and components are causing the improvement.

Eligible participants will be randomly assigned to one of the treatment groups. All subjects will undergo 6 weeks of weekly face-to-face sessions.

PACT treatment will include an initial physical assesment with feedback, identification of value-based goals, individualized physical exercise based on the DNS concept, manual therapy, addressing barriers and facilitators to self-management, and skills training to promote psychological flexibility.

UC will include an initial physical assesment with feedback, treatment considered suitable by their treating physiotherapist that will be based on exercises according to the DNS concept and manual therapy.

The self-report questionnaires will be completed by participants at baseline and 6 weeks, all to be completed at home.

Treatment will be provided by an experienced physiotherapist and will be conducted in a private room.

To avoid contamination, the same clinician will deliver both PACT and UC as CBT-based methods are sometimes employed within usual physiotherapy care.

A clinical psychologist and expert in the ACT will provide training. There will be group face-to-face training that will last 2 days followed by self-experience group training that will last 6 weeks (2 hours/week).

All PACT sessions will be audio-recorded to assesing treatment fidelity. Recordings will be used for supervision. Supervisor will be a clinical psychologist experienced in ACT and will review one tape per month.

Inclusion Criteria:

• Individuals over the age of 18
• Chronic low-back pain longer than 12 weeks
• Scoring more than 3 points in Roland-Morris Disability Questionnaire (RMDQ)
• Adequate understanding of spoken and written czech language

Exclusion Criteria:

• Prior treatment from cognitive-behavioural therapy pain management at any time and other physiotherapy treatment in the previous 6 months
• Injection therapy within 3 months
• Specific medically diagnosed lubar spine pathology (eg, fracture, cancer)
• Deteorating neurological sings
• Patients with current psychiatric illness
• Current alcohol or drug misuse