The physiological effects of daily cold-water immersion on 5-day tournament performance in international standard youth field-hockey players.

PURPOSE: This study examined the effects of daily post-exercise cold-water immersion (CWI) on match performance, perceptual recovery, and biomarkers of muscle damage and metabolic load during a 5-day international tournament of elite youth field-hockey players. METHODS: The entire German under-18 national squad (n = 18) was randomly assigned to a daily CWI- (5-min at ~ 6 °C; excluding the head; n = 9) or passive recovery (CON; n = 9) intervention. Training and match performance were assessed using a GPS-tracking system and perceived exertion (RPE). Daily ratings of delayed onset muscle soreness (DOMS), perceived stress and recovery, quality of sleep, heart-rate recovery and serum creatine kinase (CK), lactate dehydrogenase, and urea nitrogen were also recorded. Repeated-sprint ability (RSA) and counter-movement jump (CMJ) were carried out on days 1 and 5. RESULTS: There was no significance between intervention differences in time-on pitch, total distance, velocity zones, and accelerometer-base parameters during match performance (all p > 0.05). DOMS (p < 0.01), RPE (p < 0.01), and CK (p < 0.01) were significantly elevated over the course of the tournament; however, no between-intervention effects were observed (all p > 0.05). Both groups were able to maintain RSA and CMJ (all p > 0.05). CONCLUSION: In conclusion, daily post-exercise CWI did not improve match performance, perceptual recovery, or biomarkers of muscle damage and metabolic load in elite youth field-hockey players.

Whole-body cryotherapy (-110 °C) following high-intensity intermittent exercise does not alter hormonal, inflammatory or muscle damage biomarkers in trained males.

PURPOSE: This study examined the acute effects of a single session of Whole-body Cryotherapy (WBC) following severe intermittent running exercise on biomarkers of inflammation, muscle damage and stress. METHODS: Endurance-trained males (n = 11) were tested twice using a within-participant, balanced cross-over design that consisted of 5 × 5 min of high-intensity running (HIR) followed by either 3 min of WBC at -110 °C or a passive control condition (CON). Before the HIR and after 60 min of recovery a ramp-test was completed. At seven time points up to 24 hrs post exercise venous blood samples were analyzed for serum levels of interleukin 6 (IL-6), interleukin 10 (IL-10), c-reactive protein (CRP), soluble intercellular adhesion molecule-1 (sICAM-1), myoglobin, cortisol, and testosterone. RESULTS: HIR induced significant increases in all biomarkers except sICAM-1 in both recovery conditions, respectively. Compared to the CON condition WBC did not attenuate exercise- induced changes in IL-6, IL-10, sICAM-1, myoglobin, cortisol, testosterone or their ratio. Increased levels of cortisol following exercise were negatively correlated with subsequent running performance in both conditions (WBC: r = -0.61, p = 0.04; CON: r = -0.64, p = 0.04). CONCLUSION: The results of this study suggest that the postulated physiological mechanisms by which WBC is proposed to improve recovery, i.e. reductions in inflammation and muscle damage, may not be accurate.

Effects of hyperoxia during recovery from 5×30-s bouts of maximal-intensity exercise.

We test the hypothesis that breathing oxygen-enriched air (F(I)O(2) = 100%) maintains exercise performance and reduces fatigue during intervals of maximal-intensity cycling. Ten well-trained male cyclists (age 25 ± 3 years; peak oxygen uptake 64.8 ± 6.2 ml · kg(-1) · min(-1); mean ± s) were exposed to either hyperoxic or normoxic air during the 6-min intervals between five 30-s sessions of cycling at maximal intensity. The concentrations of lactate and hydrogen ions [H(+)], pH, base excess, oxygen partial pressure, and oxygen saturation in the blood were assessed before and after these sprints. The peak (P = 0.62) and mean power outputs (P = 0.83) with hyperoxic and normoxic air did not differ. The partial pressure of oxygen was 4.2-fold higher after inhaling hyperoxic air, whereas lactate concentration, pH, [H(+)], and base excess (P ≥ 0.17) were not influenced. Perceived exertion towards the end of the 6-min periods after the fourth and fifth sprints (P < 0.05) was lower with hyperoxia than normoxia (P < 0.05). These findings demonstrate that the peak and mean power outputs of athletes performing intervals of maximal-intensity cycling are not improved by inhalation of oxygen-enriched air during recovery.

Oxygen uptake, velocity at lactate threshold, and running economy in elite special forces.

OBJECTIVE: To examine the correlation of peak oxygen uptake (VO2 peak), velocity at lactate threshold (V(LT)), and running economy (RE) in a group of Special Force Squad members. METHODS: VO2 peak, V(LT), and RE of 120 male elite special force police squad members (VO2 peak, 57.4 +/- 4.3 mL minute(-1) kg(-1); age, 28.9 +/- 5.2 years; body mass index, 24.2 +/- 1.6 kg m(-2)) were tested using an incremental treadmill protocol (2.4 m second(-1), increase 0.4 m second(-1) every 5 minutes). Running velocities at the first lactate inflection point (V(LT)) and blood lactate concentration at 4 mmol L(-1) (V4) were determined. RE was defined as oxygen uptake in mL kg(-1) minute(-1) at 3.2 m second(-1). RESULTS: Analysis revealed little or no correlation between V4, V(LT), VO2 peak, and RE (r = 0.02-0.35; p = 0.01-0.80). CONCLUSIONS: (1) VO2 peak, V(LT), and RE do not correlate in elite squad members. (2) All 3 variables should be assessed when comparing inter- and intraindividual differences in endurance performance of Special Force Squad members.

Strength, Endurance, Throwing Velocity and in-Water Jump Performance of Elite German Water Polo Players.

The purpose of this study was threefold: 1) to assess the eggbeater kick and throwing performance using a number of water polo specific tests, 2) to explore the relation between the eggbeater kick and throwing performance, and 3) to investigate the relation between the eggbeater kick in the water and strength tests performed in a controlled laboratory setting in elite water polo players. Fifteen male water polo players of the German National Team completed dynamic and isometric strength tests for muscle groups (adductor, abductor, abdominal, pectoralis) frequently used during water polo. After these laboratory strength tests, six water polo specific in-water tests were conducted. The eggbeater kick assessed leg endurance and agility, maximal throwing velocity and jump height. A 400 m test and a sprint test examined aerobic and anaerobic performance. The strongest correlation was found between jump height and arm length (p < 0.001, r = 0.89). The laboratory diagnostics of important muscles showed positive correlations with the results of the in-water tests (p < 0.05, r = 0.52-0.70). Muscular strength of the adductor, abdominal and pectoralis muscles was positively related to in-water endurance agility as assessed by the eggbeater kick (p < 0.05; r = 0.53-0.66). Findings from the current study emphasize the need to assess indices of water polo performance both in and out of the water as well as the relation among these parameters to best assess the complex profile of water polo players.