Relationship between the Physical Demand of an Elite Rugby match and Indicators of Muscular Damage.
Relationship Between the Physical Demands of an Elite Rugby Match and Indicators of Muscle Damage.
Oxendale et al. published the article “The Relationship Between Match-Play Characteristics of Elite Rugby League and Indirect Markers of Muscle Damage”, in which they analyze how the physical demands of an elite rugby match are related to muscle damage and players’ recovery. To do this, professional players were monitored during official matches, assessing both the physical effort on the field and the subsequent changes in their muscular condition.
One of the most important indicators of muscle damage analyzed was creatine kinase (CK), an enzyme that increases in the blood when there are injuries to muscle fibers. Blood samples were taken before and after the matches (at 12, 36, and 60 hours) and their relationship with the type and intensity of the effort made by each player was evaluated.
In addition to CK, the study measured perceived muscle soreness, upper body strength through plyometric push-ups, and lower body performance using the Counter Movement Jump (CMJ), a vertical jump that helps detect neuromuscular fatigue.
The results showed that CK levels increased significantly at 12 and 36 hours after the match, returning to normal values by 60 hours. This confirms the presence of muscle damage after competition, as previous studies had already indicated.
One of the most important conclusions is that players who covered greater distances, performed more high-intensity runs, and accumulated more collisions had higher CK values, meaning greater muscle damage. For example, a strong correlation was found between match duration and CK levels (r = 0.90), as well as between total distance covered and CK (r = 0.86).
It was also observed that repeated high-intensity efforts (RHIE) and collisions were associated with greater muscle soreness and increases in CK. In other words, players who experienced more impacts and performed sprints with shorter recovery times showed greater signs of muscle fatigue.
On the other hand, a significant decrease in CMJ performance was observed at 12 and 36 hours post-match, indicating clear muscle fatigue in the legs. Although there was a correlation between Creatine Kinase (CK) levels and CMJ performance, as shown in the graph, this correlation was not significant. That is, although both indicators reflect fatigue during the same time periods, CK does not directly predict the loss of jump performance.
This suggests that CK and CMJ respond to different physiological mechanisms of muscle damage. While CK reflects a biochemical response from injured muscle, the CMJ represents a functional measure of neuromuscular performance, influenced by other factors such as muscle fiber type, coordination, or neural fatigue.
In contrast, a negative correlation was found between the total number of collisions and plyometric push-up power (r = -0.48), as well as with perceived muscle soreness. That is, physical contact during the game more directly affects upper body performance.
The study highlights the importance of individualizing recovery, as muscle damage and fatigue levels vary depending on the type of effort each player makes. This is especially useful for planning training in the days following competition, avoiding overtraining, and preventing injuries.
