MedXFit—Effects of 6 months CrossFit® in sedentary and inactive employees: A prospective, controlled, longitudinal, intervention study

Abstract

Abstract Background and Aims Sedentary behavior and physical inactivity are associated with musculoskeletal disorders (MSD). Muscle and mobility enhancing training is recommended to promote musculoskeletal fitness and prevent MSD. A functional fitness program emphasizing the importance of musculoskeletal fitness is provided by CrossFit®. However, data from long‐term CrossFit® interventions assessing measures of musculoskeletal fitness in sedentary and inactive individuals does not exist. Methods This prospective, controlled study investigates the effects of 6 months CrossFit® training (2×60 min/week) in inactive adults (in terms of <2 muscle or mobility enhancing training sessions per week) with predominantly sitting or standing occupations. 91 participants were initially assessed, 2 were excluded, 55 self‐selected for intervention (IG), and 34 for the control group (CG). Primary endpoint was a change in mobility (Functional Movement Screen score). Secondary endpoints were changed in strength (maximum isometric strength in kg; Dr. Wolff BackCheck®), and well‐being (WHO‐5 score). Key exploratory endpoints were changes in back‐issue measures (pain intensity, limitation, and frequency). Results 39 participants of IG and 31 of CG completed the evaluation after 6 months. The IG improved significantly more (p < 0.001) compared with the CG in the FMS (η² = 0.58), trunk extension (η² = 0.46), trunk flexion (η² = 0.47), trunk lateral flexion left (η² = 0.41), trunk lateral flexion right (η² = 0.42), upper body push (η² = 0.4), upper body pull (η² = 0.25), hip extension left (η² = 0.18), and hip extension right (η² = 0.4). Change of WHO‐5 scores did not significantly differ between groups (p = 0.55; η² = 0.01). Exploratory analysis of back‐issue data showed a higher decrease for pain intensity, limitation, and frequency in the IG compared with the CG. Conclusion This study proves for the first time within the scope of a prospective, controlled study the broad benefits of CrossFit® in inactive adults doing predominantly sedentary work.

Keywords

• exercise
• fitness
• functional movement
• health
• high‐intensity interval training
• military