Are physiological, physical, wellness and load decisive markers of starting players? A case study from a professional male soccer team

The study aim was to compare physiological, physical, accumulated wellness and load markers within a European professional soccer team between starters and non-starters. Ten starters (age: 25.1 ± 2.2 years; experience: 7.3 ± 2.3 years) and eight non starters (age: 26.1 ± 4.6; years’ experience: 8.3 ± 4.1 years) participated in the study. The study was conducted across 20 weeks where 75 training sessions and 15 matches occurred. Wellness (fatigue, quality of sleep, muscle soreness, stress and mood) and load (rating of perceived exertion (RPE), accelerations, decelerations, high-speed running and sprinting) measures were observed. Physiological evaluation consisted of a 1200 m maximum effort shuttle test while physical capacity assessment included isokinetic strength, jump ability and balance tests. Isokinetic tests were used to assess peak torque of both legs (extension and flexion at 60◦ /s and 180◦ /s), single squat jump and single hop jump were utilized to assess jump ability and Y-balance tests were employed to examine balance. Starters presented significantly higher values for peak torque extension of the non-dominant leg compared to non-starters (p = 0.038, effect size (ES) = 0.996), while non-starters showed higher values for both Y-balance postero-medial and postero lateral (p = 0.009, ES = −1.309 and p = 0.021, ES = −1.133, respectively). Accumulated duration and RPE were lower for non-starters than starters (p ≤ 0.001, ES = 1.268, and p = 0.022, ES = 1.123, respectively). The physiological and physical tests conducted in this study do not seem to determine the starting status of players, considering that only one test revealed significantly higher values for starters. Despite the lower training and match duration for non-starters, this showed that it is possible to accumulate identical load while managing wellness regardless of starting status.