Effects of cold‐water immersion of legs after training session on serum creatine kinase concentrations in rugby players

The use of methods other than passive recovery for improving recovery after intense training and competitions in sports is growing. In particular, in rugby, the use of cold water, possibly associated with active recovery (cycling), and the use of cold and hot water immersion are quite popular. In our experience, the perception of muscle soreness after heavy exercise in top‐level rugby players decreases when cold‐water immersion of legs is performed during recovery period, as also quantified by a semiquantitative scale.¹

Gill and coworkers described the effectiveness of contrast water therapy (CWT) for improving the post‐match recovery in elite rugby players.²

CWT was performed by immersion of the body to the level of the anterior superior iliac spine in one of two temperature‐controlled water baths, alternating between 1 min in cold water (8–10°C) and 2 min in hot water (40–42°C) for 9 min. The CWT, as well as low‐impact exercise postcompetition and wearing compression garments, promoted better recovery than classical passive recovery in athletes, as demonstrated by modifications in creatine kinase (CK) activity in the interstitial fluid collected from the ventral forearm. We tested the use of active recovery together with cold‐water immersion of the body to the level of the anterior superior iliac spine (5°C) after an intense training session. The session on the field started with a speed agility warm‐up followed by step work with ballistic stretching (15 min), on‐field practice (90 min) with play starts, general movement sequences (up to 8 sequences) and, finally, intense accelerations. Thus, it was a mixed‐fuel energy session, with cardiodominance and lactacid peaks, divided into phases of a 10 min work‐out, with the rest of 3 min between two consecutive phases, when the players had contacts and were in various play situations.

Three groups of 10 athletes from the Italian National team were subjected, respectively, to passive recovery, active recovery (cycling at 180 W) for 10 min followed by cold‐water immersion of the legs for 10 min, and cold‐water immersion of the legs for 10 min followed by active recovery. We measured CK in serum obtained from venous blood, drawn at 08:00 h, at rest after 18 h of physical activity, on the same day, immediately after the training session, and, finally, after passive or active and cold‐water recovery period of 20 min. We found no significant differences among the three groups when compared at rest, after training, and after passive or active and cold‐water recovery (analysis on MedCalc software). The serum CK activities found were similar to those described in the interstitial fluid before competition,² but higher than those reported in plasma after a match in Japanese rugby players.³

The statistical evaluation of CK activity in each group during the three different steps (rest, after training, after recovery) by one‐way analysis of variance gave significant differences (p<0.001) in the two groups with passive recovery and with cold‐water immersion followed by cycling. In the athletes who performed active recovery followed by cold‐water immersion, the statistical analysis gave a non‐significant result (p = 0.09; table 1).

Table 1 Serum CK activity in rugby players subjected to different recovery treatment after a training session.

	CK at rest (U/l)	CK immediately after training session (U/l)	CK after active recovery and cold‐water immersion (U/l)
Passive recovery (n = 10)	339	1028	1077
Active recovery followed by cold‐water immersion (n = 10)	248	1240	992
Cold‐water immersion followed by active recovery (n = 10)	310	1146	1230

CK, creatine kinase.

We conclude that cold‐water immersion, after training and active recovery, stabilises CK activity in top‐level rugby players and can be effective for improving recovery.