Effect of cold water immersion on 100-m sprint performance in well-trained swimmers

Cold Water Immersion Does Not Enhance Recovery and Performance After High-Intensity Interval Dorsiflexion Exercise

Cold-water immersion (CWI) has become a widely adopted method for post-exercise recovery. However, its effectiveness in restoring neuromuscular function remains inconclusive. This study examined the impact of CWI on recovery following high-intensity interval exercise (HIIE). Twelve young, recreationally active individuals (10 males, 2 females) participated in a randomized crossover study. Each session included six sets of 30-s all-out isokinetic concentric contractions of the ankle dorsiflexor and plantar flexor muscles, followed by 10 min of room temperature rest (RT) or CWI at 10°C. Neuromuscular function and intramuscular temperature were evaluated periodically over 24 h, as well as next-day fatigue resistance of the dorsiflexors. In both conditions, maximal voluntary contraction torque remained impaired for up to 3 h without significant changes in voluntary activation (p > 0.05). Electrically stimulated torque showed no difference in the fatigue-induced decline or recovery of 10 Hz torque, which also remained impaired for up to 3 h. However, 50 Hz torque recovered within 1 h following RT, whereas it remained slightly reduced for up to 3 h following CWI. The 10:50 Hz torque ratio showed immediate recovery with CWI, whereas RT recovery was delayed for up to 1 h. Notably, the ratio was significantly lower with RT at 0-, 0.5-, and 1-h post-intervention. Despite these differences, HIIE performance during a repeat bout conducted 24 h later remained similar. In conclusion, 10 min of CWI at 10°C does not enhance post-exercise recovery or next-day exercise performance following HIIE.

Effects of post-exercise cold-water immersion on performance and perceptive outcomes of competitive adolescent swimmers

PURPOSE

To evaluate the effects of repeated use of cold-water immersion (CWI) during a training week on performance and perceptive outcomes in competitive adolescent swimmers.

METHODS

This randomized-crossover study included 20 athletes, who received each intervention [CWI (14 ± 1 °C), thermoneutral water immersion (TWI) (27 ± 1 °C) as placebo, and passive recovery (PAS)] three times a week between the land-based resistance training and swim training. The interventions were performed in a randomized order with a 1-week wash-out period. We tested athletes before and after each intervention week regarding swim (100 m freestyle sprints) and functional performance (flexibility, upper and lower body power, and shoulder proprioception). We monitored athlete's perceptions (well-being, heaviness, tiredness, discomfort and pain) during testing sessions using a 5-item questionnaire. Athlete preferences regarding the interventions were assessed at the end of the study. We used generalized linear mixed models and generalized estimating equations for continuous and categorical variables, respectively (intervention x time).

RESULTS

We found a time effect for swim performance (p = .01) in which, regardless the intervention, all athletes improved sprint time at post-intervention compared to baseline. There was an intervention effect for pain (p = .04) and tiredness (p = .04), but with no significant post-hoc comparisons. We found no significant effects for other outcomes. All athletes reported a preference for CWI or TWI in relation to PAS.

CONCLUSION

The repeated use of CWI throughout a training week did not impact functional or swim performance outcomes of competitive adolescent swimmers. Perceptive outcomes were also similar across interventions; however, athletes indicated a preference for both CWI and TWI.

Effectiveness of Recovery Strategies After Training and Competition in Endurance Athletes: An Umbrella Review

BACKGROUND

Recovery strategies are used to enhance performance and reduce injury risk in athletes. In previous systematic reviews, individual recovery strategies were investigated to clarify their effectiveness for mixed groups of athletes. However, the current evidence is ambiguous, and a clear overview of (training) recovery for endurance athletes is still lacking.

METHODS

We conducted an umbrella review based on a literature search in PubMed, Cochrane Database of Systematic Reviews, and Web of Science. Reviews published in English and before December 2022 were included. Systematic reviews and meta-analyses were eligible if they investigated the effectiveness of one or more recovery strategies compared with a placebo or control group after a training session in endurance athletes.

RESULTS

Twenty-two reviews (nine systematic reviews, three meta-analyses, and ten systematic reviews with meta-analyses included) met the inclusion criteria. In total, sixty-three studies with 1100 endurance athletes were included in our umbrella review. Out of the sixty-three studies, eight provided information on training recovery time frame for data synthesis. Among them, cryotherapy and compression garments showed positive effects, while applying massage showed no effect. In general, none of the included recovery strategies showed consistent benefits for endurance athletes.

CONCLUSION

There is no particular recovery strategy that can be advised to enhance recovery between training sessions or competitions in endurance athletes. However, individual studies suggest that compression garments and cryotherapy are effective training recovery strategies. Further research should improve methodology and focus on the different time courses of the recovery process.

REGISTRATION

The review protocol was registered with the International Prospective Register of Systematic Reviews with the number CRD42021260509.

Influence of physical post-exercise recovery techniques on vagally-mediated heart rate variability: A systematic review and meta-analysis

In sports, physical recovery following exercise-induced fatigue is mediated via the reactivation of the parasympathetic nervous system (PNS). A noninvasive way to quantify the reactivation of the PNS is to assess vagally-mediated heart rate variability (vmHRV), which can then be used as an index of physical recovery. This systematic review and meta-analysis investigated the effects of physical recovery techniques following exercise-induced fatigue on vmHRV, specifically via the root mean square of successive differences (RMSSD). Randomized controlled trials from the databases PubMed, WebOfScience, and SportDiscus were included. Twenty-four studies were part of the systematic review and 17 were included in the meta-analysis. Using physical post-exercise recovery techniques displayed a small to moderate positive effect on RMSSD (k = 22, Hedges' g = 0.40, 95% confidence interval [CI] = 0.20-0.61, p = 0.04) with moderate heterogeneity. In the subgroup analyses, cold water immersion displayed a moderate to large positive effect (g = 0.75, 95% CI: 0.42-1.07) compared with none for other techniques. For exercise type, physical recovery techniques performed after resistance exercise (g = 0.69, 95% CI: 0.48-0.89) demonstrated a larger positive effect than after cardiovascular intermittent (g = 0.52, 95% CI: 0.06-0.97), while physical recovery techniques performed after cardiovascular continuous exercise had no effect. No significant subgroup differences for training status and exercise intensity were observed. Overall, physical post-exercise recovery techniques can accelerate PNS reactivation as indexed by vmHRV, but the effectiveness varies with the technique and exercise type.

Repeated cold-water immersion improves autonomic cardiac modulation following five sessions of high-intensity interval exercise

PURPOSE

The study aimed to investigate the effect of repeated cold-water immersion (CWI) after high-intensity interval exercise sessions on cardiac-autonomic modulation, neuromuscular performance, muscle damage markers, and session internal load.

METHODS

Twenty-one participants underwent five sessions of high-intensity interval exercise (6-7 bouts of 2 min; pause of 2 min) over a two-week period. Participants were allocated randomly into either a group that underwent CWI (11-min; 11 °C) or a group that performed passive recovery after each exercise session. Before the exercise sessions were performed, countermovement jump (CMJ) and heart rate variability were recorded (i.e., rMSSD, low and high frequency power and its ratio, SD1 and SD2). Exercise heart rate was calculated by recording the area under the curve (AUC) response. Internal session load was evaluated 30 min after each session. Blood concentrations of creatine kinase and lactate dehydrogenase were analyzed before the first visit and 24 h after the last sessions.

RESULTS

The CWI group presented higher rMSSD than the control group at each time point (group-effect P = 0.037). The SD1 was higher in CWI group when compared to the control group following the last exercise session (interaction P = 0.038). SD2 was higher in CWI group compared to the control group at each time point (group-effect P = 0.030). Both groups presented equal CMJ performance (P > 0.05), internal load (group-effect P = 0.702; interaction P = 0.062), heart rate AUC (group-effect P = 0.169; interaction P = 0.663), and creatine kinase and lactate dehydrogenase blood concentrations (P > 0.05).

CONCLUSION

Repeated post-exercise CWI improves cardiac-autonomic modulation. However, no differences in neuromuscular performance, muscle damage markers, or session internal load were demonstrated between the groups.

Effects of cold water immersion after exercise on fatigue recovery and exercise performance--meta analysis

Cold water immersion (CWI) is very popular as a method reducing post-exercise muscle stiffness, eliminating fatigue, decreasing exercise-induced muscle damage (EIMD), and recovering sports performance. However, there are conflicting opinions as to whether CWI functions positively or negatively. The mechanisms of CWI are still not clear. In this systematic review, we used meta-analysis aims to examine the effect of CWI on fatigue recovery after high-intensity exercise and exercise performance. A total of 20 studies were retrieved and included from PubMed, PEDro and Elsevier databases in this review. Publication years of articles ranged from 2002 to 2022. In selected studies including randomized controlled trials (RCTs) and Crossover design (COD). Analyses of subjective indicators such as delayed-onset muscle soreness (DOMS) and ratings of perceived exertion (RPE), and objective indicators such as countermovement jump (CMJ) and blood plasma markers including creatine kinase(CK), lactate/lactate dehydrogenase(LDH), C-reactive protein(CRP), and IL-6 were performed. Pooled data showed as follows: CWI resulted in a significant decline in subjective characteristics (delayed-onset muscle soreness and perceived exertion at 0 h); CWI reduced countermovement jump(CMJ) significantly at 0 h, creatine kinase(CK) was lowered at 24 h, and lactate at 24 and 48 h. There was no evidence that CWI affects C-reactive protein(CRP) and IL-6 during a 48-h recovery period. Subgroup analysis revealed that different CWI sites and water temperatures have no effect on post-exercise fatigue recovery. Recommended athletes immersed in cold water immediately after exercise, which can effectively reduce muscle soreness and accelerate fatigue recovery.

What Parameters Influence the Effect of Cold-Water Immersion on Muscle Soreness? An Updated Systematic Review and Meta-Analysis

OBJECTIVE

Our objective was to determine the efficacy of cold-water immersion (CWI) on the management of muscle soreness to identify the impact of immersion time, water temperature, CWI protocol, and type of exercise on this outcome.

DESIGN

Intervention systematic review and meta-analysis.

SETTING

MEDLINE/PubMed, Embase, Central, and SPORTDiscus databases were searched from their earliest record to July 30, 2020. Only randomized controlled trials that assessed muscle soreness comparing CWI and control were included. Studies were pooled in different subgroups regarding the used protocol: water temperature (severe or moderate cold), immersion time (short, medium, or longer time), CWI protocol (intermittent or continuous application), and type of exercise (endurance or resistance exercise). Data were pooled in a meta-analysis and described as weighted mean difference (95% confidence interval, P < 0.05).

PARTICIPANTS

Athletes and nonathletes.

INTERVENTIONS

Cold-water immersion and control condition.

MAIN OUTCOME MEASURES

Muscle soreness.

RESULTS

Forty-four studies were included. For immediate effects, CWI was superior to control regardless of water temperature and protocol, and for short and medium immersion times and endurance exercises. For delayed effects, CWI was superior to control in all subgroups except longer immersions time.

CONCLUSIONS

This study suggests that CWI is better than control for the management of muscle soreness and water temperature and CWI protocol do not influence this result, but only short and medium immersions times presented positive effects. Aiming immediate effects, the best results suggest CWI application only after endurance exercises, while delayed effect CWI was superior both after endurance and resistance exercises.

Functional Impact of Post-exercise Cooling and Heating on Recovery and Training Adaptations: Application to Resistance, Endurance, and Sprint Exercise

The application of post-exercise cooling (e.g., cold water immersion) and post-exercise heating has become a popular intervention which is assumed to increase functional recovery and may improve chronic training adaptations. However, the effectiveness of such post-exercise temperature manipulations remains uncertain. The aim of this comprehensive review was to analyze the effects of post-exercise cooling and post-exercise heating on neuromuscular function (maximal strength and power), fatigue resistance, exercise performance, and training adaptations. We focused on three exercise types (resistance, endurance and sprint exercises) and included studies investigating (1) the early recovery phase, (2) the late recovery phase, and (3) repeated application of the treatment. We identified that the primary benefit of cooling was in the early recovery phase (< 1 h post-exercise) in improving fatigue resistance in hot ambient conditions following endurance exercise and possibly enhancing the recovery of maximal strength following resistance exercise. The primary negative impact of cooling was with chronic exposure which impaired strength adaptations and decreased fatigue resistance following resistance training intervention (12 weeks and 4–12 weeks, respectively). In the early recovery phase, cooling could also impair sprint performance following sprint exercise and could possibly reduce neuromuscular function immediately after endurance exercise. Generally, no benefits of acute cooling were observed during the 24–72-h recovery period following resistance and endurance exercises, while it could have some benefits on the recovery of neuromuscular function during the 24–48-h recovery period following sprint exercise. Most studies indicated that chronic cooling does not affect endurance training adaptations following 4–6 week training intervention. We identified limited data employing heating as a recovery intervention, but some indications suggest promise in its application to endurance and sprint exercise.

Anaerobic performance after 3-day consecutive CO2-rich cold-water immersion in physically active males

Background Objective

We investigated the effects of a 3-day consecutive CO₂-rich cold (20 °C) water immersion (CCWI) following a high-intensity intermittent test (HIIT) on subjects' sublingual temperature (T_sub), blood lactate ([La]b), and heart rate (HR) compared to cold (20 °C) tap-water immersion (CWI) or passive recovery (PAS).

Methods

Thirty-two subjects were randomly allocated into three groups (CCWI, CWI, and PAS), each of which completed 4 consecutive days of cycling experiments. HR, T_sub, and [La]b were recorded on each day of exercise testing (immersion from Day 1 to Day 3 and Day 4). HIIT consisted of 8 sets of 20-sec maximum exercise at an intensity of 120% of VO₂max with 10-sec passive rest. The mean and peak power, and peak pedal repetitions (PPR) within HIIT were averaged and the decline in PPR (ΔPPR) from Day 1 to Day 4 was measured.

Results

In CCWI and CWI, HR declined significantly following each immersion, with CCWI showing the larger reduction (p < 0.001). At Day 2, CCWI showed a significantly lower [La]b compared to PAS (p < 0.01). The changes in mean and peak power from Day 1 to Day 4 did not differ among the groups (p = 0.302). ΔPPR of HIIT was significantly correlated with the HR and [La]b values after immersions (ΔPPR-HR: r² = 0.938, p < 0.001, ΔPPR-[La]b: r² = 0.999, p < 0.001).

Conclusions

These findings indicate that CCWI is a promising intervention for maintaining peak performance in high-intensity intermittent exercise, which is associated with a reduction in [La]b and HR.

Impact of Cold-Water Immersion Compared with Passive Recovery Following a Single Bout of Strenuous Exercise on Athletic Performance in Physically Active Participants: A Systematic Review with Meta-analysis and Meta-regression

Background

Studies investigating the effects of cold-water immersion (CWI) on the recovery of athletic performance, perceptual measures and creatine kinase (CK) have reported mixed results in physically active populations.

Objectives

The purpose of this systematic review was to investigate the effects of CWI on recovery of athletic performance, perceptual measures and CK following an acute bout of exercise in physically active populations.

Study Design

Systematic review with meta-analysis and meta-regression.

Methods

A systematic search was conducted in September 2021 using Medline, SPORTDiscus, Scopus, Web of Science, Cochrane Library, EmCare and Embase databases. Studies were included if they were peer reviewed and published in English, included participants who were involved in sport or deemed physically active, compared CWI with passive recovery methods following an acute bout of strenuous exercise and included athletic performance, athlete perception and CK outcome measures. Studies were divided into two strenuous exercise subgroups: eccentric exercise and high-intensity exercise. Random effects meta-analyses were used to determine standardised mean differences (SMD) with 95% confidence intervals. Meta-regression analyses were completed with water temperature and exposure durations as continuous moderator variables.

Results

Fifty-two studies were included in the meta-analyses. CWI improved the recovery of muscular power 24 h after eccentric exercise (SMD 0.34 [95% CI 0.06–0.62]) and after high-intensity exercise (SMD 0.22 [95% CI 0.004–0.43]), and reduced serum CK (SMD − 0.85 [95% CI − 1.61 to − 0.08]) 24 h after high-intensity exercise. CWI also improved muscle soreness (SMD − 0.89 [95% CI − 1.48 to − 0.29]) and perceived feelings of recovery (SMD 0.66 [95% CI 0.29–1.03]) 24 h after high-intensity exercise. There was no significant influence on the recovery of strength performance following either eccentric or high-intensity exercise. Meta-regression indicated that shorter time and lower temperatures were related to the largest beneficial effects on serum CK (duration and temperature dose effects) and endurance performance (duration dose effects only) after high-intensity exercise.

Conclusion

CWI was an effective recovery tool after high-intensity exercise, with positive outcomes occurring for muscular power, muscle soreness, CK, and perceived recovery 24 h after exercise. However, after eccentric exercise, CWI was only effective for positively influencing muscular power 24 h after exercise. Dose–response relationships emerged for positively influencing endurance performance and reducing serum CK, indicating that shorter durations and lower temperatures may improve the efficacy of CWI if used after high-intensity exercise.

Funding

Emma Moore is supported by a Research Training Program (Domestic) Scholarship from the Australian Commonwealth Department of Education and Training.

Protocol registration

Open Science Framework: 10.17605/OSF.IO/SRB9D.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-022-01644-9.

Post-exercise Cold Water Immersion Effects on Physiological Adaptations to Resistance Training and the Underlying Mechanisms in Skeletal Muscle: A Narrative Review

Post-exercise cold-water immersion (CWI) is a popular recovery modality aimed at minimizing fatigue and hastening recovery following exercise. In this regard, CWI has been shown to be beneficial for accelerating post-exercise recovery of various parameters including muscle strength, muscle soreness, inflammation, muscle damage, and perceptions of fatigue. Improved recovery following an exercise session facilitated by CWI is thought to enhance the quality and training load of subsequent training sessions, thereby providing a greater training stimulus for long-term physiological adaptations. However, studies investigating the long-term effects of repeated post-exercise CWI instead suggest CWI may attenuate physiological adaptations to exercise training in a mode-specific manner. Specifically, there is evidence post-exercise CWI can attenuate improvements in physiological adaptations to resistance training, including aspects of maximal strength, power, and skeletal muscle hypertrophy, without negatively influencing endurance training adaptations. Several studies have investigated the effects of CWI on the molecular responses to resistance exercise in an attempt to identify the mechanisms by which CWI attenuates physiological adaptations to resistance training. Although evidence is limited, it appears that CWI attenuates the activation of anabolic signaling pathways and the increase in muscle protein synthesis following acute and chronic resistance exercise, which may mediate the negative effects of CWI on long-term resistance training adaptations. There are, however, a number of methodological factors that must be considered when interpreting evidence for the effects of post-exercise CWI on physiological adaptations to resistance training and the potential underlying mechanisms. This review outlines and critiques the available evidence on the effects of CWI on long-term resistance training adaptations and the underlying molecular mechanisms in skeletal muscle, and suggests potential directions for future research to further elucidate the effects of CWI on resistance training adaptations.

Correlation between skin temperature in the lower limbs and biochemical marker, performance data, and clinical recovery scales

The aim of this study was to evaluate the correlation between tools commonly used in the detection of physiological changes, such as clinical complaints, a biochemical marker of muscle injury, and performance data during official matches, with infrared thermography, which has been commonly used in the possible tracking of musculoskeletal injuries in athletes. Twenty-two athletes from a professional soccer club (age 27.7 ± 3.93 years; BMI 24.35 ± 1.80 kg/cm²) were followed during the season of a national championship, totaling 19 matches with an interval of 7 days between matches. At each match, the athletes used a Global Positioning System (GPS) device to collect performance data. Forty-eight hours after each match, every athlete’s perception of recovery, fatigue, and pain was documented. Blood was collected for creatine kinase (CK) analysis, and infrared thermography was applied. Only athletes who presented pain above 4 in either limb were included for thermographic analysis. Each thermographic image was divided into 14 regions of interest. For statistical analysis, we included only the images that showed differences ≥ 1° C. Data normality was verified by the Kolmogorov-Smirnov test with Dallal-Wilkinson-Lilliefors correction. We used the Pearson correlation coefficient to verify the correlation between infrared thermography and the biochemical marker, performance data, and clinical recovery scales. No correlation was observed between mean skin temperature and blood CK levels, pain level, perception of recovery, and fatigue perception (r <0.2, p>0.05). Thus, infrared thermography did not correlate with CK level, pain, fatigue perception, or recovery, nor with performance variables within the field.

Cold Water Immersion After a Handball Training Session: The Relationship Between Physical Data and Sensorial Experience

The aim of this study was to examine the relationship between the physiological data from subjects and their reported sensory experiences during two types of recovery methods following a handball training session. Female handball players (average age: 21.4 ± 1.3 years; weight: 59.2 ± 3.3 kg; height: 158 ± 3 cm; body mass index, 23.4 ± 2.0 kg.m⁻²) carried out an athletic training session (rating of perceived exertion RPE: 14.70 ± 0.89) with either a passive recovery (PR) period or cold water immersion (CWI) for 14 min) (cross-over design). Physiological data were collected during the recovery period: CWI had a greater effect than PR on heart rate (HR; bpm), the higher frequencies (HF) of heart rate variability (HRV: 46.44 ± 21.50 vs. 24.12 ± 17.62), delayed onset muscle soreness (DOMS: 1.37 ± 0.51 vs. 2.12 ± 1.25), and various reported emotional sensations. Spectrum HRV analysis showed a significant increase in HF during CWI. Sensorial experiences during the recovery periods were gathered from verbatim reports 24 h later. Players' comments about CWI revealed a congruence between the physiological data and sensorial reports. They used words such as: “thermal shock,” “regeneration,” “resourcefulness,” “dynamism,” and “disappearance of pain” to describe their sensations. In conclusion, this study demonstrated the link between physiological and experiential data during CWI and we propose that action of the parasympathetic system on the autonomic nervous system can, at least in part, explain the observed correlations between the corporeal data measured and the sensorial experiences reported.

Effects of COVID-19 lockdown on heart rate variability

INTRODUCTION

Strict lockdown rules were imposed to the French population from 17 March to 11 May 2020, which may result in limited possibilities of physical activity, modified psychological and health states. This report is focused on HRV parameters kinetics before, during and after this lockdown period.

METHODS

95 participants were included in this study (27 women, 68 men, 37 ± 11 years, 176 ± 8 cm, 71 ± 12 kg), who underwent regular orthostatic tests (a 5-minute supine followed by a 5-minute standing recording of heart rate (HR)) on a regular basis before (BSL), during (CFN) and after (RCV) the lockdown. HR, power in low- and high-frequency bands (LF, HF, respectively) and root mean square of the successive differences (RMSSD) were computed for each orthostatic test, and for each position. Subjective well-being was assessed on a 0-10 visual analogic scale (VAS). The participants were split in two groups, those who reported an improved well-being (WB+, increase >2 in VAS score) and those who did not (WB-) during CFN.

RESULTS

Out of the 95 participants, 19 were classified WB+ and 76 WB-. There was an increase in HR and a decrease in RMSSD when measured supine in CFN and RCV, compared to BSL in WB-, whilst opposite results were found in WB+ (i.e. decrease in HR and increase in RMSSD in CFN and RCV; increase in LF and HF in RCV). When pooling data of the three phases, there were significant correlations between VAS and HR, RMSSD, HF, respectively, in the supine position; the higher the VAS score (i.e., subjective well-being), the higher the RMSSD and HF and the lower the HR. In standing position, HRV parameters were not modified during CFN but RMSSD was correlated to VAS.

CONCLUSION

Our results suggest that the strict COVID-19 lockdown likely had opposite effects on French population as 20% of participants improved parasympathetic activation (RMSSD, HF) and rated positively this period, whilst 80% showed altered responses and deteriorated well-being. The changes in HRV parameters during and after the lockdown period were in line with subjective well-being responses. The observed recordings may reflect a large variety of responses (anxiety, anticipatory stress, change on physical activity…) beyond the scope of the present study. However, these results confirmed the usefulness of HRV as a non-invasive means for monitoring well-being and health in this population.

Cold water immersion attenuates anabolic signaling and skeletal muscle fiber hypertrophy, but not strength gain, following whole-body resistance training

We determined the effects of cold water immersion (CWI) on long-term adaptations and post-exercise molecular responses in skeletal muscle before and after resistance training. Sixteen men (22.9 ± 4.6 y; 85.1 ± 17.9 kg; mean ± SD) performed resistance training (3 day/wk) for 7 wk, with each session followed by either CWI [15 min at 10°C, CWI (COLD) group, n = 8] or passive recovery (15 min at 23°C, control group, n = 8). Exercise performance [one-repetition maximum (1-RM) leg press and bench press, countermovement jump, squat jump, and ballistic push-up], body composition (dual X-ray absorptiometry), and post-exercise (i.e., +1 and +48 h) molecular responses were assessed before and after training. Improvements in 1-RM leg press were similar between groups [130 ± 69 kg, pooled effect size (ES): 1.53 ± 90% confidence interval (CI) 0.49], whereas increases in type II muscle fiber cross-sectional area were attenuated with CWI (-1,959 ± 1,675 µM² ; ES: -1.37 ± 0.99). Post-exercise mechanistic target of rapamycin complex 1 signaling (rps6 phosphorylation) was blunted for COLD at post-training (POST) +1 h (-0.4-fold, ES: -0.69 ± 0.86) and POST +48 h (-0.2-fold, ES: -1.33 ± 0.82), whereas basal protein degradation markers (FOX-O1 protein content) were increased (1.3-fold, ES: 2.17 ± 2.22). Training-induced increases in heat shock protein (HSP) 27 protein content were attenuated for COLD (-0.8-fold, ES: -0.94 ± 0.82), which also reduced total HSP72 protein content (-0.7-fold, ES: -0.79 ± 0.57). CWI blunted resistance training-induced muscle fiber hypertrophy, but not maximal strength, potentially via reduced skeletal muscle protein anabolism and increased catabolism. Post-exercise CWI should therefore be avoided if muscle hypertrophy is desired.NEW & NOTEWORTHY This study adds to existing evidence that post-exercise cold water immersion attenuates muscle fiber growth with resistance training, which is potentially mediated by attenuated post-exercise increases in markers of skeletal muscle anabolism coupled with increased catabolism and suggests that blunted muscle fiber growth with cold water immersion does not necessarily translate to impaired strength development.

The Influence of Post-Exercise Cold-Water Immersion on Adaptive Responses to Exercise: A Review of the Literature

Post-exercise cold-water immersion (CWI) is used extensively in exercise training as a means to minimise fatigue and expedite recovery between sessions. However, debate exists around its merit in long-term training regimens. While an improvement in recovery following a single session of exercise may improve subsequent training quality and stimulus, reports have emerged suggesting CWI may attenuate long-term adaptations to exercise training. Recent developments in the understanding of the molecular mechanisms governing the adaptive response to exercise in human skeletal muscle have provided potential mechanistic insight into the effects of CWI on training adaptations. Preliminary evidence suggests that CWI may blunt resistance signalling pathways following a single exercise session, as well as attenuate key long-term resistance training adaptations such as strength and muscle mass. Conversely, CWI may augment endurance signalling pathways and the expression of genes key to mitochondrial biogenesis following a single endurance exercise session, but have little to no effect on the content of proteins key to mitochondrial biogenesis following long-term endurance training. This review explores current evidence regarding the underlying molecular mechanisms by which CWI may alter cellular signalling and the long-term adaptive response to exercise in human skeletal muscle.

Effects of different recovery strategies following a half-marathon on fatigue markers in recreational runners

Purpose

To investigate the effects of different recovery strategies on fatigue markers following a prolonged running exercise.

Methods

46 recreational male runners completed a half-marathon, followed by active recovery (ACT), cold water immersion (CWI), massage (MAS) or passive recovery (PAS). Countermovement jump height, muscle soreness and perceived recovery and stress were measured 24h before the half-marathon (pre), immediately after the recovery intervention (post_rec) and 24h after the race (post₂₄). In addition, muscle contractile properties and blood markers of fatigue were determined at pre and post₂₄.

Results

Magnitude-based inferences revealed substantial differences in the changes between the groups. At post_rec, ACT was harmful to perceived recovery (ACT vs. PAS: effect size [ES] = −1.81) and serum concentration of creatine kinase (ACT vs. PAS: ES = 0.42), with CWI being harmful to jump performance (CWI vs. PAS: ES = −0.98). It was also beneficial for reducing muscle soreness (CWI vs. PAS: ES = −0.88) and improving perceived stress (CWI vs. PAS: ES = −0.64), with MAS being beneficial for reducing muscle soreness (MAS vs. PAS: ES = −0.52) and improving perceived recovery (MAS vs. PAS: ES = 1.00). At post₂₄, both CWI and MAS were still beneficial for reducing muscle soreness (CWI vs. PAS: ES = 1.49; MAS vs. PAS: ES = 1.12), with ACT being harmful to perceived recovery (ACT vs. PAS: ES = −0.68), serum concentration of creatine kinase (ACT vs. PAS: ES = 0.84) and free-testosterone (ACT vs. PAS: ES = −0.91).

Conclusions

In recreational runners, a half-marathon results in fatigue symptoms lasting at least 24h. To restore subjective fatigue measures, the authors recommend CWI and MAS, as these recovery strategies are more effective than PAS, with ACT being even disadvantageous. However, runners must be aware that neither the use of ACT nor CWI or MAS had any beneficial effect on objective fatigue markers.

Acute, chronic, and combined pulmonary responses to swimming in competitive swimmers

The combined effects of swimming on the inspiratory muscles and pulmonary functions are not well known. The aim of the present study was to determine the acute, chronic, and combined effects of swimming on the pulmonary functions and respiratory muscles of competitive swimmers. Thirty males (15 in the experimental group [EG] and 15 in the control group [CG]) participated in this study. The EG subjects participated in an 8-week swim training program and performed 1 day before and after an 8-week 100-m swimming event. Pulmonary functions and respiratory muscle strength were measured immediately before and after the swimming event in the EG and before and after an 8-week period in the CG. The obtained data were analyzed using repeated measures one-way analysis of variance, least significant difference, and independent- and paired-sample t-tests. Swimming exerted negative acute effects (p < 0.05) and positive chronic effects (p < 0.05) on respiratory muscle strength and pulmonary functions. Further, the negative acute effects decreased the combined effects of the chronic and acute effects of swimming on respiratory muscle strength and pulmonary functions (p < 0.05). The results indicated that swimming exerts negative acute, positive chronic, and combined effects on respiratory muscle strength and pulmonary functions.

Overload blunts baroreflex only in overreached athletes

OBJECTIVES

Heart rate variability (HRV) is commonly used to diagnose overreaching and monitor athletes' responses to training. Baroreflex sensitivity (BRS) is modified by changes in training load and might be another means to detect overreaching. The goal of this study was to assess BRS and HRV changes in two groups of athletes responding either negatively (FOR) or positively (AF) to similar training overload.

DESIGN

Fifteen athletes performed 2-week baseline (BSL) training followed by 3-week overload (+45%; OVL) and 2-week recovery (-20%; RCV).

METHODS

HRV, training load and subjective fatigue were measured daily via questionnaires. BRS, salivary cortisol and testosterone, and submaximal exercise and maximal 3-km run performances were measured at the end of each period.

RESULTS

Based on their performance change during OVL, 8 athletes were diagnosed as FOR and 7 as AF. Subjective fatigue was increased in FOR athletes during OVL. BRS increased in AF but not in FOR athletes during RCV. At the end of RCV, cortisol and testosterone were higher than BSL in both groups.

CONCLUSIONS

Three weeks of similar training overload can induce either performance enhancement or overreaching. The changes in submaximal exercise and maximal performances and in subjective fatigue were the fastest-responding parameters that distinguished the two groups of athletes during OVL. Training overload blunted the increase in BRS in FOR only. Most of the differences in BRS were observed during the recovery period. BRS appears to be a more sensitive parameter than HRV for early monitoring of responses to training.

Influence of recovery strategies upon performance and perceptions following fatiguing exercise: a randomized controlled trial

Background

Despite debate regarding their effectiveness, many different post-exercise recovery strategies are used by athletes. This study compared five post-exercise recovery strategies (cold water immersion, contrast water immersion, active recovery, a combined cold water immersion and active recovery and a control condition) to determine which is most effective for subsequent short-term performance and perceived recovery.

Methods

Thirty-four recreationally active males undertook a simulated team-game fatiguing circuit followed by the above recovery strategies (randomized, 1 per week). Prior to the fatiguing exercise, and at 1, 24 and 48 h post-exercise, perceptual, flexibility and performance measures were assessed.

Results

Contrast water immersion significantly enhanced perceptual recovery 1 h after fatiguing exercise in comparison to active and control recovery strategies. Cold water immersion and the combined recovery produced detrimental jump power performance at 1 h compared to the control and active recovery strategies. No recovery strategy was different to the control at 24 and 48 h for either perceptual or performance variables.

Conclusion

For short term perceptual recovery, contrast water therapy should be implemented and for short-term countermovement power performance an active or control recovery is desirable. At 24 and 48 h, no superior recovery strategy was detected.

Trial registration

Retrospectively registered; ISRCTN14415088; 5/11/2017.

A customised cold-water immersion protocol favours one-size-fits-all protocols in improving acute performance recovery

The purpose of the present study was to investigate whether a customised cold-water immersion (CWIc) protocol was more effective in enhancing acute performance recovery than a one-size-fits-all CWI (CWIs) or active recovery (AR) protocol. On three separate testing days, 10 healthy, physically active, non-smoking males completed the same fatiguing protocol (60 squat jumps and a 2'30″ all-out cycling time-trial) followed by CWIc (12°C, 10-17 min), CWIs (15°C, 10 min) or AR (60 W, 10 min). Outcome measures to assess acute recovery were heart rate variability (HRV) as HRVrecovery, muscle power (MP) as absolute and relative decline, and muscle soreness (MS) at 0 and 24 h. HRVrecovery for CWIc was significantly higher compared to CWIs (p = .026, r = 0.74) and AR (p = .000, r = 0.95). The relative decline in MP after CWIc was significantly lower than after CWIs (p = .017, r = 0.73). MS 0 h and MS 24 h post-intervention were not different after CWIc compared to CWIs and AR (p > .05). The findings of the present study demonstrated that CWIc outperforms CWIs and AR in the acute recovery of cardiovascular (HRV) and CWIs in neuromuscular (MP) performance with no differences in MS. To optimise the effects of CWI, contributions of the protocol duration and water temperature should be considered to guarantee an optimal customised dose.

Team sport athletes' perceptions and use of recovery strategies: a mixed-methods survey study

BACKGROUND

A variety of recovery strategies are used by athletes, although there is currently no research that investigates perceptions and usage of recovery by different competition levels of team sport athletes.

METHODS

The recovery techniques used by team sport athletes of different competition levels was investigated by survey. Specifically this study investigated if, when, why and how the following recovery strategies were used: active land-based recovery (ALB), active water-based recovery (AWB), stretching (STR), cold water immersion (CWI) and contrast water therapy (CWT).

RESULTS

Three hundred and thirty-one athletes were surveyed. Fifty-seven percent were found to utilise one or more recovery strategies. Stretching was rated the most effective recovery strategy (4.4/5) with ALB considered the least effective by its users (3.6/5). The water immersion strategies were considered effective/ineffective mainly due to psychological reasons; in contrast STR and ALB were considered to be effective/ineffective mainly due to physical reasons.

CONCLUSIONS

This study demonstrates that athletes may not be aware of the specific effects that a recovery strategy has upon their physical recovery and thus athlete and coach recovery education is encouraged. This study also provides new information on the prevalence of different recovery strategies and contextual information that may be useful to inform best practice among coaches and athletes.

Effects of Cold Water Immersion on Muscle Oxygenation During Repeated Bouts of Fatiguing Exercise: A Randomized Controlled Study

Postexercise cold water immersion has been advocated to athletes as a means of accelerating recovery and improving performance. Given the effects of cold water immersion on blood flow, evaluating in vivo changes in tissue oxygenation during cold water immersion may help further our understanding of this recovery modality. This study aimed to investigate the effects of cold water immersion on muscle oxygenation and performance during repeated bouts of fatiguing exercise in a group of healthy young adults. Twenty healthy subjects performed 2 fatiguing bouts of maximal dynamic knee extension and flexion contractions both concentrically on an isokinetic dynamometer with a 10-min recovery period in between. Subjects were randomly assigned to either a cold water immersion (treatment) or passive recovery (control) group. Changes in muscle oxygenation were monitored continuously using near-infrared spectroscopy. Muscle performance was measured with isokinetic dynamometry during each fatiguing bout. Skin temperature, heart rate, blood pressure, and muscle soreness ratings were also assessed. Repeated measures ANOVA analysis was used to evaluate treatment effects. The treatment group had a significantly lower mean heart rate and lower skin temperature compared to the control group (P < 0.05). Cold water immersion attenuated a reduction in tissue oxygenation in the second fatiguing bout by 4% when compared with control. Muscle soreness was rated lower 1 day post-testing (P < 0.05). However, cold water immersion had no significant effect on muscle performance in subsequent exercise. As the results show that cold water immersion attenuated decreased tissue oxygenation in subsequent exercise performance, the metabolic response to exercise after cold water immersion is worthy of further exploration.

The effects of cold water immersion with different dosages (duration and temperature variations) on heart rate variability post-exercise recovery: A randomized controlled trial

OBJECTIVES

The aim of the present study was to investigate the effects of cold water immersion during post-exercise recovery, with different durations and temperatures, on heart rate variability indices.

DESIGN

Hundred participants performed a protocol of jumps and a Wingate test, and immediately afterwards were immersed in cold water, according to the characteristics of each group (CG: control; G1: 5' at 9±1°C; G2: 5' at 14±1°C; G3: 15' at 9±1°C; G4: 15' at 14±1°C).

METHODS

Analyses were performed at baseline, during the CWI recuperative technique (TRec) and 20, 30, 40, 50 and 60min post-exercise. The average HRV indices of all RR-intervals in each analysis period (MeanRR), standard deviation of normal RR-intervals (SDNN), square root of the mean of the sum of the squares of differences between adjacent RR-intervals (RMSSD), spectral components of very low frequency (VLF), low frequency (LF) and high frequency (HF), scatter of points perpendicular to the line of identity of the Poincaré Plot (SD1) and scatter points along the line of identity (SD2) were assessed.

RESULTS

Mean RR, VLF and LF presented an anticipated return to baseline values at all the intervention groups, but the same was observed for SDNN and SD2 only in the immersion for 15min at 14°C group (G4). In addition, G4 presented higher values when compared to CG.

CONCLUSIONS

These findings demonstrate that if the purpose of the recovery process is restoration of cardiac autonomic modulation, the technique is recommended, specifically for 15min at 14°C.

Cold applications for recovery in adolescent athletes: a systematic review and meta analysis

Recovery and regeneration modalities have been developed empirically over the years to help and support training programmes aimed at maximizing athletic performance. Professional athletes undergo numerous training sessions, characterized by differing modalities of varying volumes and intensities, with the aim of physiological adaptation leading to improved performance. Scientific support to athletes focuses on improving the chances of a training programme producing the largest adaptive response. In competition it is mainly targeted at maximizing the chances of optimal performance and recovery when high performance levels are required repeatedly in quick succession (e.g. heats/finals). In recent years, a lot of emphasis has been put on recovery modalities. In particular, emphasis has been placed on the need to reduce the delayed onset of muscle soreness (DOMS) typically evident following training and competitive activities inducing a certain degree of muscle damage. One of the most used recovery modalities consists of cold-water immersion and/or ice/cold applications to muscles affected by DOMS. While the scientific literature has provided a rationale for such modalities to reduce pain in athletes and recreationally active adults, it is doubtful if this rationale is appropriate to aid training with adolescent athletes. In particular, since these methods have been suggested to potentially impair the muscle remodeling process leading to muscle hypertrophy. While this debate is still active in the literature, many coaches adopt such practices in youth populations, simply transferring what they see in elite sportspeople directly; without questioning the rationale, safety or effectiveness as well as the potential for such activity to reduce the adaptive potential of skeletal muscle remodeling in adolescent athletes. The aim of this review was to assess the current knowledge base on the use of ice/cold applications for recovery purposes in adolescent athletes in order to provide useful guidelines for sports scientists, medical practitioners, physiotherapists and coaches working with such populations as well as developing research questions for further research activities in this area. Based on the current evidence, it seems clear that evidence for acute benefits of such interventions are scarce and more work is needed to ascertain the physiological implications on a pre or peri-pubertal population.

Postexercise cold water immersion benefits are not greater than the placebo effect

PURPOSE

Despite a general lack of understanding of the underlying mechanisms, cold water immersion (CWI) is widely used by athletes for recovery. This study examined the physiological merit of CWI for recovery from high-intensity exercise by investigating if the placebo effect is responsible for any acute performance or psychological benefits.

METHODS

Thirty males (mean ± SD: age, 24 ± 5 yr; VO2 peak, 51.1 ± 7.0 mL · kg(-1) · min(-1)) performed an acute high-intensity interval training session, comprised of 4 × 30-s sprints, immediately followed by one of the following three 15-min recovery conditions: CWI (10.3°C ± 0.2°C), thermoneutral water immersion placebo (TWP) (34.7°C ± 0.1°C), or thermoneutral water immersion control (TWI) (34.7°C ± 0.1°C). An intramuscular thermistor was inserted during exercise and recovery to record muscle temperature. Swelling (thigh girth), pain threshold/tolerance, interleukin 6 concentration, and total leukocyte, neutrophil, and lymphocyte counts were recorded at baseline, postexercise, postrecovery, and 1, 24, and 48 h postexercise. A maximal voluntary isometric contraction (MVC) of the quadriceps was performed at the same time points, with the exception of postexercise. Self-assessments of readiness for exercise, fatigue, vigor, sleepiness, pain, and belief of recovery effectiveness were also completed.

RESULTS

Leg strength after the MVC and ratings of readiness for exercise, pain, and vigor were significantly impaired in TWI compared with those in CWI and TWP which were similar to each other.

CONCLUSIONS

A recovery placebo administered after an acute high-intensity interval training session is superior in the recovery of muscle strength over 48 h as compared with TWI and is as effective as CWI. This can be attributed to improved ratings of readiness for exercise, pain, and vigor, suggesting that the commonly hypothesized physiological benefits surrounding CWI are at least partly placebo related.

Heart rate variability and swimming

BACKGROUND AND OBJECTIVES

Professionals in the domain of swimming have a strong interest in implementing research methods in evaluating and improving training methods to maximize athletic performance and competitive outcome. Heart rate variability (HRV) has gained attention in research on sport and exercise to assess autonomic nervous system activity underlying physical activity and sports performance. Studies on swimming and HRV are rare. This review aims to summarize the current evidence on the application of HRV in swimming research and draws implications for future research.

METHODS

A systematic search of databases (PubMed via MEDLINE, PSYNDEX and Embase) according to the PRISMA statement was employed. Studies were screened for eligibility on inclusion criteria: (a) empirical investigation (HRV) in humans (non-clinical); (b) related to swimming; (c) peer-reviewed journal; and (d) English language.

RESULTS

The search revealed 194 studies (duplicates removed), of which the abstract was screened for eligibility. Fourteen studies meeting the inclusion criteria were included in the review. Included studies broadly fell into three classes: (1) control group designs to investigate between-subject differences (i.e. swimmers vs. non-swimmers, swimmers vs. other athletes); (2) repeated measures designs on within-subject differences of interventional studies measuring HRV to address different modalities of training or recovery; and (3) other studies, on the agreement of HRV with other measures.

CONCLUSIONS

The feasibility and possibilities of HRV within this particular field of application are well documented within the existing literature. Future studies, focusing on translational approaches that transfer current evidence in general practice (i.e. training of athletes) are needed.

Effect of run training and cold-water immersion on subsequent cycle training quality in high-performance triathletes

The purpose of the study was to investigate the effect of cold-water immersion (CWI) on physiological, psychological, and biochemical markers of recovery and subsequent cycling performance after intensive run training. Seven high-performance male triathletes (age: 28.6 ± 7.1 years; cycling VO2peak: 73.4 ± 10.2 ml · kg(-1) · min(-1)) completed 2 trials in a randomized crossover design consisting of 7 × 5-minute running intervals at 105% of individual anaerobic threshold followed by either CWI (10 ± 0.5° C) or thermoneutral water immersion (TNI; 34 ± 0.5° C). Subjects immersed their legs in water 5 times for 60 seconds with 60-second passive rest between each immersion. Nine hours after immersion, inflammatory and muscle damage markers, and perceived recovery measures were obtained before the subjects completed a 5-minute maximal cycling test followed by a high-quality cycling interval training set (6 × 5-minute intervals). Power output, heart rate, blood lactate (La), and rating of perceived exertion (RPE) were also recorded during the cycling time-trial and interval set. Performance was enhanced (change, ± 90% confidence limits) in the CWI condition during the cycling interval training set (power output [W · kg(-1)], 2.1 ± 1.7%, La [mmol · L(-1)], 18 ± 18.1%, La:RPE, 19.8 ± 17.5%). However, there was an unclear effect of CWI on 5-minute maximal cycling time-trial performance, and there was no significant influence on perceptual measures of fatigue/recovery, despite small to moderate effects. The effect of CWI on the biochemical markers was mostly unclear, however, there was a substantial effect for interleukin-10 (20 ± 13.4%). These results suggest that compared with TNI, CWI may be effective for enhancing cycling interval training performance after intensive interval-running training.

The Properties of Water and their Applications for Training

The biological effects of immersion in water, which are related to the fundamental principles of hydrodynamics, may be beneficial in certain training contexts. The effects and physical properties of water, such as density, hydrostatic pressure and buoyancy are highly useful resources for training, when used as a counterbalance to gravity, resistance, a compressor and a thermal conductor. Not only does the aquatic medium enable a wider range of activities to be used in a context of low joint impact, but it also constitutes a useful tool in relation to sports rehabilitation, since it allows the athlete to return to training earlier or to continue with high-intensity exercise while ensuring both low joint impact and greater comfort for the individual concerned. Moreover, this medium enables the stimulation of metabolic and neuromuscular systems, followed by their corresponding physiological adaptations allowing both to maintain and improve athletic performance. Hydrotherapy can also play a beneficial role in an athlete’s recovery, helping to prevent as well as treat muscle damage and soreness following exercise.

The effect of different water immersion temperatures on post-exercise parasympathetic reactivation

Purpose

We evaluated the effect of different water immersion (WI) temperatures on post-exercise cardiac parasympathetic reactivation.

Methods

Eight young, physically active men participated in four experimental conditions composed of resting (REST), exercise session (resistance and endurance exercises), post-exercise recovery strategies, including 15 min of WI at 15°C (CWI), 28°C (TWI), 38°C (HWI) or control (CTRL, seated at room temperature), followed by passive resting. The following indices were assessed before and during WI, 30 min post-WI and 4 hours post-exercise: mean R-R (mR-R), the natural logarithm (ln) of the square root of the mean of the sum of the squares of differences between adjacent normal R–R (ln rMSSD) and the ln of instantaneous beat-to-beat variability (ln SD1).

Results

The results showed that during WI mRR was reduced for CTRL, TWI and HWI versus REST, and ln rMSSD and ln SD1 were reduced for TWI and HWI versus REST. During post-WI, mRR, ln rMSSD and ln SD1 were reduced for HWI versus REST, and mRR values for CWI were higher versus CTRL. Four hours post exercise, mRR was reduced for HWI versus REST, although no difference was observed among conditions.

Conclusions

We conclude that CWI accelerates, while HWI blunts post-exercise parasympathetic reactivation, but these recovery strategies are short-lasting and not evident 4 hours after the exercise session.

Water immersion recovery for athletes: effect on exercise performance and practical recommendations

Water immersion is increasingly being used by elite athletes seeking to minimize fatigue and accelerate post-exercise recovery. Accelerated short-term (hours to days) recovery may improve competition performance, allow greater training loads or enhance the effect of a given training load. However, the optimal water immersion protocols to assist short-term recovery of performance still remain unclear. This article will review the water immersion recovery protocols investigated in the literature, their effects on performance recovery, briefly outline the potential mechanisms involved and provide practical recommendations for their use by athletes. For the purposes of this review, water immersion has been divided into four techniques according to water temperature: cold water immersion (CWI; ≤20 °C), hot water immersion (HWI; ≥36 °C), contrast water therapy (CWT; alternating CWI and HWI) and thermoneutral water immersion (TWI; >20 to <36 °C). Numerous articles have reported that CWI can enhance recovery of performance in a variety of sports, with immersion in 10-15 °C water for 5-15 min duration appearing to be most effective at accelerating performance recovery. However, the optimal CWI duration may depend on the water temperature, and the time between CWI and the subsequent exercise bout appears to influence the effect on performance. The few studies examining the effect of post-exercise HWI on subsequent performance have reported conflicting findings; therefore the effect of HWI on performance recovery is unclear. CWT is most likely to enhance performance recovery when equal time is spent in hot and cold water, individual immersion durations are short (~1 min) and the total immersion duration is up to approximately 15 min. A dose-response relationship between CWT duration and recovery of exercise performance is unlikely to exist. Some articles that have reported CWT to not enhance performance recovery have had methodological issues, such as failing to detect a decrease in performance in control trials, not performing full-body immersion, or using hot showers instead of pools. TWI has been investigated as both a control to determine the effect of water temperature on performance recovery, and as an intervention itself. However, due to conflicting findings it is uncertain whether TWI improves recovery of subsequent exercise performance. Both CWI and CWT appear likely to assist recovery of exercise performance more than HWI and TWI; however, it is unclear which technique is most effective. While the literature on the use of water immersion for recovery of exercise performance is increasing, further research is required to obtain a more complete understanding of the effects on performance.

Training adaptation and heart rate variability in elite endurance athletes: opening the door to effective monitoring

The measurement of heart rate variability (HRV) is often considered a convenient non-invasive assessment tool for monitoring individual adaptation to training. Decreases and increases in vagal-derived indices of HRV have been suggested to indicate negative and positive adaptations, respectively, to endurance training regimens. However, much of the research in this area has involved recreational and well-trained athletes, with the small number of studies conducted in elite athletes revealing equivocal outcomes. For example, in elite athletes, studies have revealed both increases and decreases in HRV to be associated with negative adaptation. Additionally, signs of positive adaptation, such as increases in cardiorespiratory fitness, have been observed with atypical concomitant decreases in HRV. As such, practical ways by which HRV can be used to monitor training status in elites are yet to be established. This article addresses the current literature that has assessed changes in HRV in response to training loads and the likely positive and negative adaptations shown. We reveal limitations with respect to how the measurement of HRV has been interpreted to assess positive and negative adaptation to endurance training regimens and subsequent physical performance. We offer solutions to some of the methodological issues associated with using HRV as a day-to-day monitoring tool. These include the use of appropriate averaging techniques, and the use of specific HRV indices to overcome the issue of HRV saturation in elite athletes (i.e., reductions in HRV despite decreases in resting heart rate). Finally, we provide examples in Olympic and World Champion athletes showing how these indices can be practically applied to assess training status and readiness to perform in the period leading up to a pinnacle event. The paper reveals how longitudinal HRV monitoring in elites is required to understand their unique individual HRV fingerprint. For the first time, we demonstrate how increases and decreases in HRV relate to changes in fitness and freshness, respectively, in elite athletes.

Monitoring training status with HR measures: do all roads lead to Rome?

Measures of resting, exercise, and recovery heart rate are receiving increasing interest for monitoring fatigue, fitness and endurance performance responses, which has direct implications for adjusting training load (1) daily during specific training blocks and (2) throughout the competitive season. However, these measures are still not widely implemented to monitor athletes' responses to training load, probably because of apparent contradictory findings in the literature. In this review I contend that most of the contradictory findings are related to methodological inconsistencies and/or misinterpretation of the data rather than to limitations of heart rate measures to accurately inform on training status. I also provide evidence that measures derived from 5-min (almost daily) recordings of resting (indices capturing beat-to-beat changes in heart rate, reflecting cardiac parasympathetic activity) and submaximal exercise (30- to 60-s average) heart rate are likely the most useful monitoring tools. For appropriate interpretation at the individual level, changes in a given measure should be interpreted by taking into account the error of measurement and the smallest important change of the measure, as well as the training context (training phase, load, and intensity distribution). The decision to use a given measure should be based upon the level of information that is required by the athlete, the marker's sensitivity to changes in training status and the practical constrains required for the measurements. However, measures of heart rate cannot inform on all aspects of wellness, fatigue, and performance, so their use in combination with daily training logs, psychometric questionnaires and non-invasive, cost-effective performance tests such as a countermovement jump may offer a complete solution to monitor training status in athletes participating in aerobic-oriented sports.

Analysis of sex differences in open-water ultra-distance swimming performances in the FINA World Cup races in 5 km, 10 km and 25 km from 2000 to 2012

BACKGROUND

The present study investigated the changes in swimming speeds and sex differences for elite male and female swimmers competing in 5 km, 10 km and 25 km open-water FINA World Cup races held between 2000 and 2012.

METHODS

The changes in swimming speeds and sex differences across years were analysed using linear, non-linear, and multi-level regression analyses for the annual fastest and the annual ten fastest competitors.

RESULTS

For the annual fastest, swimming speed remained stable for men and women in 5 km (5.50 ± 0.21 and 5.08 ± 0.19 km/h, respectively), in 10 km (5.38 ± 0.21 and 5.05 ± 0.26 km/h, respectively) and in 25 km (5.03 ± 0.32 and 4.58 ± 0.27 km/h, respectively). In the annual ten fastest, swimming speed remained constant in 5 km in women (5.02 ± 0.19 km/h) but decreased significantly and linearly in men from 5.42 ± 0.03 km/h to 5.39 ± 0.02 km/h. In 10 km, swimming speed increased significantly and linearly in women from 4.75 ± 0.01 km/h to 5.74 ± 0.01 km/h but remained stable in men at 5.36 ± 0.21 km/h. In 25 km, swimming speed decreased significantly and linearly in women from 4.60 ± 0.06 km/h to 4.44 ± 0.08 km/h but remained unchanged at 4.93 ± 0.34 km/h in men. For the annual fastest, the sex difference in swimming speed remained unchanged in 5 km (7.6 ± 3.0%), 10 km (6.1 ± 2.5%) and 25 km (9.0 ± 3.7%). For the annual ten fastest, the sex difference remained stable in 5 km at 7.6 ± 0.6%, decreased significantly and linearly in 10 km from 7.7 ± 0.7% to 1.2 ± 0.3% and increased significantly and linearly from 4.7 ± 1.4% to 9.6 ± 1.5% in 25 km.

CONCLUSIONS

To summarize, elite female open-water ultra-distance swimmers improved in 10 km but impaired in 25 km leading to a linear decrease in sex difference in 10 km and a linear increase in sex difference in 25 km. The linear changes in sex differences suggest that women will improve in the near future in 10 km, but not in 25 km.

Central and peripheral adjustments during high-intensity exercise following cold water immersion

PURPOSE

We investigated the acute effects of cold water immersion (CWI) or passive recovery (PAS) on physiological responses during high-intensity interval training (HIIT).

METHODS

In a crossover design, 14 cyclists completed 2 HIIT sessions (HIIT1 and HIIT2) separated by 30 min. Between HIIT sessions, they stood in cold water (10 °C) up to their umbilicus, or at room temperature (27 °C) for 5 min. The natural logarithm of square-root of mean squared differences of successive R-R intervals (ln rMSSD) was assessed pre- and post-HIIT1 and HIIT2. Stroke volume (SV), cardiac output (Q), O2 uptake (VO2), total muscle hemoglobin (t Hb) and oxygenation of the vastus lateralis were recorded (using near infrared spectroscopy); heart rate, Q, and VO2 on-kinetics (i.e., mean response time, MRT), muscle de-oxygenation rate, and anaerobic contribution to exercise were calculated for HIIT1 and HIIT2.

RESULTS

ln rMSSD was likely higher [between-trial difference (90% confidence interval) [+13.2% (3.3; 24.0)] after CWI compared with PAS. CWI also likely increased SV [+5.9% (-0.1; 12.1)], possibly increased Q [+4.4% (-1.0; 10.3)], possibly slowed Q MRT [+18.3% (-4.1; 46.0)], very likely slowed VO2 MRT [+16.5% (5.8; 28.4)], and likely increased the anaerobic contribution to exercise [+9.7% (-1.7; 22.5)].

CONCLUSION

CWI between HIIT slowed VO2 on-kinetics, leading to increased anaerobic contribution during HIIT2. This detrimental effect of CWI was likely related to peripheral adjustments, because the slowing of VO2 on-kinetics was twofold greater than that of central delivery of O2 (i.e., Q). CWI has detrimental effects on high-intensity aerobic exercise performance that persist for ≥ 45 min.

Cold water immersion recovery following intermittent-sprint exercise in the heat

This study examined the effects of cold water immersion (CWI) on recovery of neuromuscular function following simulated team-sport exercise in the heat. Ten male team-sport athletes performed two sessions of a 2 × 30-min intermittent-sprint exercise (ISE) in 32°C and 52% humidity, followed by a 20-min CWI intervention or passive recovery (CONT) in a randomized, crossover design. The ISE involved a 15-m sprint every minute separated by bouts of hard running, jogging and walking. Voluntary and evoked neuromuscular function, ratings of perceived muscle soreness (MS) and blood markers for muscle damage were measured pre- and post-exercise, immediately post-recovery, 2-h and 24-h post-recovery. Measures of core temperature (Tcore), heart rate (HR), capillary blood and perceptions of exertion, thermal strain and thirst were also recorded at the aforementioned time points. Post-exercise maximal voluntary contraction (MVC) and activation (VA) were reduced in both conditions and remained below pre-exercise values for the 24-h recovery (P < 0.05). Increased blood markers of muscle damage were observed post-exercise in both conditions and remained elevated for the 24-h recovery period (P < 0.05). Comparative to CONT, the post-recovery rate of reduction in Tcore, HR and MS was enhanced with CWI whilst increasing MVC and VA (P < 0.05). In contrast, 24-h post-recovery MVC and activation were significantly higher in CONT compared to CWI (P = 0.05). Following exercise in the heat, CWI accelerated the reduction in thermal and cardiovascular load, and improved MVC alongside increased central activation immediately and 2-h post-recovery. However, despite improved acute recovery CWI resulted in an attenuated MVC 24-h post-recovery.

Effects of age and spa treatment on match running performance over two consecutive games in highly trained young soccer players

The aim of this study was to examine the effect of age and spa treatment (i.e. combined sauna, cold water immersion, and jacuzzi) on match running performance over two consecutive matches in highly trained young soccer players. Fifteen pre- (age 12.8 ± 0.6 years) and 13 post- (15.9 ± 1 y) peak height velocity (PHV) players played two matches (Matches 1 and 2) within 48 h against the same opposition, with no specific between-match recovery intervention (control). Five post-PHV players also completed another set of two consecutive matches, with spa treatment implemented after the first match. Match running performance was assessed using a global positioning system with very-high-intensity running (> 16.1-19.0 km · h(-1)), sprinting distance (>19 km · h(-1)), and peak match speed determined. Match 2 very-high-intensity running was "possibly" impaired in post-PHV players (-9 ± 33%; ± 90% confidence limits), whereas it was "very likely" improved for the pre-PHV players (+27 ± 22%). The spa treatment had a beneficial impact on Match 2 running performance, with a "likely" rating for sprinting distance (+30 ± 67%) and "almost certain" for peak match speed (+6.4 ± 3%). The results suggest that spa treatment is an effective recovery intervention for post-PHV players, while its value in pre-PHV players is questionable.

The effect of post-exercise hydrotherapy on subsequent exercise performance and heart rate variability

We investigated the effect of hydrotherapy on time-trial performance and cardiac parasympathetic reactivation during recovery from intense training. On three occasions, 18 well-trained cyclists completed 60 min high-intensity cycling, followed 20 min later by one of three 10-min recovery interventions: passive rest (PAS), cold water immersion (CWI), or contrast water immersion (CWT). The cyclists then rested quietly for 160 min with R-R intervals and perceptions of recovery recorded every 30 min. Cardiac parasympathetic activity was evaluated using the natural logarithm of the square root of mean squared differences of successive R-R intervals (ln rMSSD). Finally, the cyclists completed a work-based cycling time trial. Effects were examined using magnitude-based inferences. Differences in time-trial performance between the three trials were trivial. Compared with PAS, general fatigue was very likely lower for CWI (difference [90% confidence limits; -12% (-18; -5)]) and CWT [-11% (-19; -2)]. Leg soreness was almost certainly lower following CWI [-22% (-30; -14)] and CWT [-27% (-37; -15)]. The change in mean ln rMSSD following the recovery interventions (ln rMSSD(Post-interv)) was almost certainly higher following CWI [16.0% (10.4; 23.2)] and very likely higher following CWT [12.5% (5.5; 20.0)] compared with PAS, and possibly higher following CWI [3.7% (-0.9; 8.4)] compared with CWT. The correlations between performance, ln rMSSD(Post-interv) and perceptions of recovery were unclear. A moderate correlation was observed between ln rMSSD(Post-interv) and leg soreness [r = -0.50 (-0.66; -0.29)]. Although the effects of CWI and CWT on performance were trivial, the beneficial effects on perceptions of recovery support the use of these recovery strategies.

Does the Time Frame Between Exercise Influence the Effectiveness of Hydrotherapy for Recovery?

An increase in research investigating recovery strategies has occurred alongside the increase in usage of recovery by elite athletes. Because there is inconsistent evidence regarding the benefits of recovery on performance, it is necessary to examine research design to identify possible strategies that enhance performance in different athlete settings. The purpose of this review is to examine available recovery literature specifically related to the time frame between performance assessments to identify considerations for both research design and practical use of recovery techniques.