Abstract
This study investigated longitudinal changes in strength- and power-related performance across an entire competitive season in elite soccer players using a frequent and systematic monitoring approach. Twenty-three professional players competing in the Brazilian first division were monitored over seven consecutive months. Athletes performed two to three resistance training (RT) sessions per week, with one weekly "control" session used to adjust training loads and assess neuromuscular status through bar-derived measures obtained in the half-squat exercise. Relative power (RP), relative strength (RS), and estimated one-repetition maximum (1RM) were recorded across 28 training sessions using the load associated with maximum power output. Weekly variations were analyzed using a 4-week rolling average, and pre-, mid-, and post-season periods were compared using repeated-measures ANOVA. Across the season, RP, RS, and 1RM exhibited a gradual and consistent positive trend. While only isolated meaningful changes were detected when individual sessions were compared with rolling averages, significant improvements were observed at the post-season time point compared with both pre- and mid-season values (p < 0.05). Notably, despite a modest ~5% increase from pre- to post-testing, absolute training loads did not change significantly across the season, indicating that performance gains were achieved without meaningful increases in training load magnitude. These findings demonstrate that a power-oriented RT model, supported by continuous monitoring and load adjustments, can effectively preserve and enhance strength and power throughout a competitive soccer season. This approach appears to mitigate commonly reported in-season declines in neuromuscular performance and offers a practical strategy for managing RT under congested competitive schedules.