The goal of this clinical trial is to learn if short exercise breaks at work can prevent muscle and joint pain in workers. The main questions it aims to answer are:

Do strength exercises help workers move better and feel less pain?

Are strength exercises better than stretching exercises for worker health?

Researchers will compare a strength exercise program to a mobility (stretching) program to see which one works better to improve physical health and work ability.

Participants will:

Perform short exercise breaks (5 minutes) at their workplace every day for 8 weeks.

Attend one supervised session per week to learn the exercises.

Complete simple physical tests (like standing up from a chair) and answer surveys about their health at the start and end of the study.

This is a quasi-experimental study with parallel assignment. The study evaluates the effectiveness of active pauses (brief workplace exercise interventions) preventing musculoskeletal disorders. Recruitment and intervention are conducted in collaboration with "Recuperación Funcional Gurea S.Coop.Peq" at various companies in the Basque Country.

Group Allocation:

Participants are assigned to one of two groups based on their work center or worker preference to maximize participation and adherence in a real-world setting.

Interventions:

Both groups follow an 8-week program consisting of daily 5-minute sessions.

Experimental Arm (Strength): Participants perform high-intensity interval training based on resistance exercises. It involves 4 specific exercises targeting the shoulder, back, and legs using elastic bands or body weight. The intensity is monitored to reach a high level of effort.

Active Comparator Arm (Mobility): Participants perform a standard routine of 12 mobility and static stretching exercises. These are low-intensity movements designed to mobilize joints and relax muscles without inducing fatigue.

Assessments:

The Principal Investigator conducts assessments at three time points:

Baseline (Week 0): Before starting the program.

Post-Intervention (Week 8): Immediately after the 8-week program.

Follow-up (Week 20): 3 months after the intervention ends.

Outcomes:

The study measures functional capacity (30-second Sit-to-Stand test), isometric strength (handgrip and shoulder), and self-reported health using the "Senior Working Life Questionnaire" (pain intensity, work ability, and vitality).

Inclusion Criteria:

• Active workers.
• Aged 18 years or older.
• Capability to perform vigorous physical exercise.

Exclusion Criteria:

• Medical contraindications to physical exercise.
• Recent surgery.
• Pregnancy.