Chronic adaptations and acute neuromuscular responses following five months of periodized CrossFit® training in national-level athletes

Objective: This study evaluated the longitudinal effects of a 5-month structured CrossFit® training program on physiological, neuromuscular, and perceptual adaptations, with a specific focus on post-activation performance enhancement (PAPE) dynamics in national-level athletes. Methods: Eleven national-level CrossFit® athletes (age: 30.8 ± 7.3 years; BMI: 22.7 ± 3.6 kg/m²; back squat 1RM: 166.8 ± 57.2 kg; training experience: 4.6 ± 0.9 years) completed a 5-month periodized training program characterized by planned undulations in volume and intensity. Neuromuscular performance (via countermovement jump [CMJ]), physiological markers, and perceptual outcomes were monitored across the macrocycle. To evaluate PAPE, acute pre- and post-session neuromuscular assessments were conducted across three benchmark CrossFit® workouts: Cindy, Bergeron, and DT. Results: The undulating training model successfully induced periodized load variation over 5 months, resulting in baseline gains in overall well-being and general neuromuscular capacity. Notably, session-specific PAPE responses varied according to workout structure: acute PAPE (enhanced post-session CMJ performance) was consistently elicited following the bodyweight and mixed-modal conditioning sessions (Cindy and Bergeron). In contrast, no acute PAPE response occurred following the heavy weightlifting session (DT), where post-session fatigue blunted potentiation. Furthermore, the overall 5-month training plan enhanced the athletes' capacity to exhibit acute PAPE responses post-intervention. Conclusion: A 5-month periodized CrossFit® program effectively drives long-term neuromuscular adaptations while augmenting acute PAPE capacity in trained athletes. However, acute PAPE induction is task-dependent: high-volume bodyweight and mixed conditioning workouts (Cindy, Bergeron) effectively trigger PAPE, whereas heavy metabolic resistance workouts (DT) favor fatigue over potentiation. These findings highlight the role of workout structure when utilizing benchmark sessions to elicit acute potentiating effects or planning post-activation protocols in competitive athletes.