Acute effects of three recovery techniques on certain physical, motor performance and haematological components in university-level rugby players
Rugby has become a popular team sport worldwide with players training harder and competing more frequently, placing a great physiological demand on their bodies. To retain this performance level, players need to recover sufficiently between training and competitions. Two popular recovery techniques used are cold water immersion (CWI) and contrast water therapy (CWT). Despite numerous publications a lack still exists with regard to these specific recovery methods on physical and haematological parameters. Against this background, the main objectives of this study were firstly, to determine the effects of CWI compared to those of passive recovery (PAR) over a 48-hour period on physical and haematological parameters after an intense anaerobic exercise session in a cohort of male university-level rugby players. Secondly, to determine the effects of CWT compared to those of PAR over a 48-hour period on physical and haematological parameters after an intense anaerobic exercise session in a cohort of male university-level rugby players. Twenty-three rugby players of the North-West University participated in the study. The players were randomly assigned to either a control (n = 11; age: 20.1±0.3 y) or experimental (n = 12; age: 19.9±0.3 y) group. Participants reported to the laboratory where base line measurements were taken on certain physical (vertical jump test (VJT) height, VJT peak speed, VJT peak power and grip strength) and haematological (base excess (BEx), blood lactate (BLa-), calcium (Ca+), bicarbonate (HCO3), haemoglobin, haematocrit, pH level, partial oxygen level (PO2), partial carbon dioxide (PCO2), plasma glucose, potassium (K+), saturated oxygen (SO2), sodium (Na+) and total carbon dioxide (TCO2)) components. Thereafter participants were accompanied to the field to complete an intense anaerobic exercise session, followed by a recovery period of either CWI vs. PAR (week 1) or CWT vs. PAR (week 2). The recovery session comprised of either sitting passively in a still area (PAR), or immersion of CWI (8–10°C), or alternating immersions of five cycles between cold (1 min; 8–10°C) and warm water (3min; 40-42°C), totalling 20 minutes. Exactly three minutes, 24 and 48 hours after the recovery intervention all the measurements were re-taken to assess acute and longer-term effects of recovery. Descriptive statistics were followed by a linear mixed model analysis with an autoregressive 1 heterogeneous (AR1-Heterogeneous) structure, and between-group differences were examined using a one-way analysis of variance (ANOVA). Significance was set at p ≤0.05. Effect sizes were calculated to determine practical significance per recovery intervention as well as within groups. CWI indicated better recovery than PAR, with three out of the nine variables (BLa-, Na+ and haemoglobin) returning at 0 h post-recovery, and five (PO2, plasma glucose, VJT height, VJT peak power, VJT peak speed) only at 24 h post-CWI. In contrast, the PAR-group did not demonstrate recovery in any of the variables at 0 h post-PAR. However, an improvement was seen in VJT height across all time points. Four (BLa-, haemoglobin, VJT peak power and VJT peak speed) out of a possible nine variables recovered at 24 h with an additional two (PO2 and grip strength) variables showing recuperation at 48 h. A significant decrease (p ≤0.05) was seen in VJT height, PO2 and Na+ from post-anaerobic to immediately following either CWI or PAR (except for VJT height). Significant increases (p ≤0.05) were observed in VJT height, plasma glucose, and Na+ from 0 h post-recovery to 48 h post-recovery for both CWI and PAR. PO2 also significantly increased (p ≤0.05) from 0 h to 24 and 48 h post-CWI and for the PAR-group at 48 h. CWI tended to have a faster recovery rate than PAR over a 24-h period. The CWT vs. PAR showed the same trend, at 0-hours, six variables (BLa-, haemoglobin, VJT-height, VJT peak-power, VJT peak-speed and grip strength) was restored to base line, whereas plasma glucose recovered at 24-hours post-CWT. In addition, players’ jump and grip strength performance improved from base line. The PAR-group demonstrated recovery at 0 hours in four variables (BLa-, VJT height, VJT peak-speed and grip strength), and two variables (Na+ and haemoglobin) at 24-hours and plasma glucose at 48 hours. A significant decrease (p ≤0.05) was seen in haemoglobin and BLa- from post-anaerobic to either 24 or 48 hours for both groups. A significant increase in plasma glucose and PO2 from 0 to 24 hours was observed in both groups. No significant intergroup change in physical components was noticed. However, intergroup results indicated CWT to be superior to PAR with statistical significance observed in BLa- and grip strength (p ≤0.05) at various time points. The conclusion drawn from the above-mentioned results is that a recovery session comprising either 20-minutes of CWI or CWT may lead to significantly better physical components and restoration of haematological components in university-level rugby players compared to that of passive recovery. However, a detrimental effect was noticed in some components over the recovery period.
- Health Sciences