To Jump or Cycle? Monitoring Neuromuscular Function in Rugby Union Players.

Gregory Roe, Joshua Darrall-Jones, Kevin Till, Padraic Phibbs, Dale Read, Jonathon Weakley, Ben Jones

The purpose of this study was to evaluate changes in performance of a 6-second cycle ergometer test (CET) and countermovement jump (CMJ) during a 6-week training block in professional rugby union players. Twelve young professional rugby union players performed two CET and CMJ on the first and fourth morning of every week prior to the commencement of daily training during a 6-week training block. Standardised changes in the highest score of two CET and CMJ efforts were assessed using linear mixed modelling and magnitude-based inferences. Following increases in training load during weeks three to five, moderate decreases in CMJ peak and mean power, and small decreases in flight-time were observed during weeks five and six that were very likely to almost certainly greater than the smallest worthwhile change, suggesting neuromuscular fatigue. However, only small decreases, possibly greater than the smallest worthwhile change, were observed in CET peak power. Changes in CMJ peak and mean power, were moderately greater than in CET peak power during this period, while the difference between flight-time and CET peak power was small. The greater weekly changes in CMJ metrics in comparison to CET may indicate differences in the capacities of these tests to measure training induced lower-body neuromuscular fatigue in rugby union players. However, future research is needed to ascertain the specific modes of training that elicit changes in CMJ and CET in order to determine the efficacy of each test for monitoring neuromuscular function in rugby union players.