How does mental and physical fatigue affect a rugby player’s force production during scrummaging?

Sammanfattning: Aims: This study investigates the effects of physical fatigue, mental fatigue and their combinations on the ability of rugby players to produce force during rugby scrummaging. Method: 10 male subjects (Mean age = 27.4 ± 3.92, Weight =102.9kg ± 10.96) were recruited from local rugby union football clubs in the Stockholm area. Scrummaging force measurements were collected following and before treatments (control), after a 30-min mental task and after a physical fatigue protocol. The mean peak force was calculated by averaging the force data 1 second around the highest peak of force during a 5 second sustained push. Results: Mean force decreased significantly after the physical fatigue (PF) protocol compared to the control (CON) (PF = 1740 ± 342 N vs. CON = 2007.5 ± 359 N. P= 0.0009) and combinations of physical and mental fatigue (PMF) or mental and physical fatigue (MPF) were also found to significantly decrease compared to the control (PMF = 1750 ± 348N vs. CON = 2007.5 ± 359N. P=0.0014 and MPF = 1818 ± 335N vs. CON = 2007.5 ± 359N. P=0.026). Mental fatigue did not significantly decrease mean peak force during the sustained push of a rugby scrum (MF = 1912 ± 321N vs. CON = 2007.5 ± 359N. P=0.52). Conclusion: Physical fatigue reduces the ability of rugby players to produce force during rugby scrummaging, however mental fatigue does not. Furthermore, mental fatigue does not exacerbate the effects of physical fatigue on scrummaging performance.