The role of training in the development of adaptive mechanisms in freedivers

Influence of CrossFit and Deep End Fitness training on mental health and coping in athletes

Physical exercise is known to improve mental health. Athletes can experience unique physical and emotional stressors, which can deteriorate mental health and cognitive function. Training apathy can lead to cognitive dissonance and further degrade performance by promoting maladaptive, avoidance coping strategies. Introduction of psychosocial and training variables, such as those used in CrossFit (CF) and other community-based fitness programs with strong peer support have been shown to help reduce training apathy and negative affect. Here, we explored whether addition of psychophysiological variation, experienced as "hunger for air" during underwater breath-hold exercises, could provide unique mental health benefits for athletes. We studied the influence of CF and Deep End Fitness (DEF), a community-based underwater fitness program, on several outcome measures of mental health and emotional well-being in volunteer athletes. We observed a significant reduction in stress scores of both the control CF training group and the experimental DEF group. We found that DEF produced a significant improvement in positive affect while CF training did not. Further supportive of our hypothesis that the psychological and biological stressors experienced in underwater, breath-hold training cause positive adaptive changes and benefits, DEF training uniquely increased problem-based coping. While our observations demonstrate both CF and DEF training can improve mental health in athletes, DEF produced additional, unique benefits to positive coping and attitudes of athletes. Future studies should further evaluate the broader benefits of community-based, underwater training programs on psychological and physiological health in athletes and the public.

Training methods for maximal static apnea performance: a systematic review and meta-analysis

INTRODUCTION

Currently, there is an increase in people practicing freediving (FD) both in competition and leisure. As a sports practice, its modalities are grouped into static, dynamic, and constant weight apnea. The aim of this systematic review and meta-analysis (PROSPERO-CRD42021230322) was to identify the training methods used to improve the static apnea time (AT) performance.

EVIDENCE ACQUISITION

Ten training protocols were analyzed from eight studies published until March 09, 2022. The effect size (Hedge's g) and its confidence interval (CI<inf>95%</inf>) were calculated from the AT measured pre- and post-training.

EVIDENCE SYNTHESIS

Three different apnea training methods were verified, the breath-hold (BH) that uses BH exercises, physical training with strength and cardiorespiratory exercises, and cross training that combines BH exercises with physical training. These training methods were applied to 138 participants of both sexes with or without experience in apnea episode or diving practice. In general, the AT improvement showed a large effect after the interventions (g=1.30, CI<inf>95%</inf>=0.85-1.76, P<0.01).

CONCLUSIONS

All three methods were effective in improving static AT, however from the existing protocols is not possible to recommend an ideal to improve AT and therefore FD performance.

The Implications of the Diving Response in Reducing Panic Symptoms

Increased CO₂ sensitivity is common in panic disorder (PD) patients. Free divers who are known for their exceptional breathing control have lower CO₂ sensitivity due to training effects. This study aimed to investigate the immediate effects of cold facial immersion (CFI), breath holding and CO₂ challenges on panic symptoms. Healthy participants and patients with PD were subjected to four experimental conditions in a randomly assigned order. The four conditions were (a) breath-holding (BH), (b) CFI for 30 s, (c) CO₂ challenge, and (d) CO₂ challenge followed by CFI. Participants completed a battery of psychological measures, and physiological data (heart rate and respiration rate) were collected following each experimental condition. Participants with PD were unable to hold their breath for as long as normal controls; however, this finding was not significant, potentially due to a small sample size. Significant reductions in both physiological and cognitive symptoms of panic were noted in the clinical group following the CFI task. As hypothesized, the CFI task exerted demonstrable anxiolytic effects in the clinical group in this study by reducing heart rate significantly and lessening self-reported symptoms of anxiety and panic. This outcome demonstrates the promise of the CFI task for clinical applications.

Physiology of static breath holding in elite apneists

NEW FINDINGS

What is the topic of this review? This review provides an up-to-date assessment of the physiology involved with extreme static dry-land breath holding in trained apneists. What advances does it highlight? We specifically highlight the recent findings involved with the cardiovascular, cerebrovascular and metabolic function during a maximal breath hold in elite apneists.

ABSTRACT

Breath-hold-related activities have been performed for centuries, but only recently, within the last ∼30 years, has it emerged as an increasingly popular competitive sport. In apnoea sport, competition relates to underwater distances or simply maximal breath-hold duration, with the current (oxygen-unsupplemented) static breath-hold record at 11 min 35 s. Remarkably, many ultra-elite apneists are able to suppress respiratory urges to the point where consciousness fundamentally limits a breath-hold duration. Here, arterial oxygen saturations as low as ∼50% have been reported. In such cases, oxygen conservation to maintain cerebral functioning is critical, where responses ascribed to the mammalian dive reflex, e.g. sympathetically mediated peripheral vasoconstriction and vagally mediated bradycardia, are central. In defence of maintaining global cerebral oxygen delivery during prolonged breath holds, the cerebral blood flow may increase by ∼100% from resting values. Interestingly, near the termination of prolonged dry static breath holds, recent studies also indicate that reductions in the cerebral oxidative metabolism can occur, probably attributable to the extreme hypercapnia and irrespective of the hypoxaemia. In this review, we highlight and discuss the recent data on the cardiovascular, metabolic and, particularly, cerebrovascular function in competitive apneists performing maximal static breath holds. The physiological adaptation and maladaptation with regular breath-hold training are also summarized, and future research areas in this unique physiological field are highlighted; particularly, the need to determine the potential long-term health impacts of extreme breath holding.

Vitamin D Supplementation and Physical Activity of Young Soccer Players during High-Intensity Training

The aim of this study was to confirm that vitamin D supplementation of young soccer players during eight-week high-intensity training would have a significant effect on their motion activity. The subjects were divided into two groups: the experimental one, which was supplemented with vitamin D (SG, n = 20), and the placebo group (PG, n = 16), which was not supplemented with vitamin D. All the players were subjected to the same soccer training, described as High-Intensity Interval Training (HIIT). The data of the vitamin D status, time motion parameters and heart rate were collected just before and after the intervention. A significant increase in 25(OH)D concentration (119%) was observed in the supplemented group, while the non-supplemented group showed a decrease of 8.4%. Based on the obtained results, it was found that physical activity indicators in the players were significantly improved during small-sided games at the last stage of the experiment. However, taking into account the effect of supplementation with vitamin D, there were no statistically significant differences between the placebo and the supplemented groups; thus, the effect size of the conducted experiment was trivial.

Neurocognitive Markers During Prolonged Breath-Holding in Freedivers: An Event-Related EEG Study

Since little is known concerning the psychological, cognitive, and neurophysiological factors that are involved in and important for phases of prolonged breath-holding (pBH) in freedivers, the present study uses electroencephalography (EEG) to investigate event-related neurocognitive markers during pBH of experienced freedivers that regularly train pBH. The purpose was to determine whether the well-known neurophysiological modulations elicited by hypoxic and hypercapnic conditions can also be detected during pBH induced hypoxic hypercapnia. Ten experienced free-divers (all male, aged 35.10 ± 7.89 years) were asked to hold their breath twice for 4 min per instance. During the first pBH, a checker board reversal task was presented and in the second four-min pBH phase a classical visual oddball paradigm was performed. A visual evoked potential (VEP) as an index of early visual processing (i.e., latencies and amplitudes of N75, P100, and N145) and the latency and amplitude of a P300 component (visual oddball paradigm) as an index of cognitive processing were investigated. In a counter-balanced cross-over design, all tasks were once performed during normal breathing (B), and once during pBH. All components were then compared between an early pBH (0–2 min) and a later pBH stage (2–4 min) and with the same time phases without pBH (i.e., during normal breathing). Statistical analyses using analyses of variance (ANOVA) revealed that comparisons between B and pBH yielded no significant changes either in the amplitude and latency of the VEP or in the P300. This indicates that neurocognitive markers, whether in an early visual processing stream or at a later cognitive processing stage, were not affected by pBH in experienced free-divers.

Suggestions for Judo Training with Pacing Strategy and Decision Making by Judo Championship Phases

The present study aimed to compare pacing and decision making of athletes competing in judo, with particular attention paid to effort-pause ratios occurring in the championship phases of the Olympic Games and non-Olympic Games. The sample was composed of 53,403 sequential actions analyzed during 611 performances of the non-Olympic Games (eliminatory n = 330, quarterfinals n = 60, semi-final n = 88, repechage n = 21, third place playoff n = 26, and final n = 79) and 163 from the Olympic Games (eliminatory n = 71, quarterfinals n = 13, semi-final n = 26, repechage n = 20, third place playoff n = 24, and final n = 14). The analysis of effort-pause ratios included separating bouts into states of approach, gripping, attack, groundwork and pause, according to frequency and time. A Markov multi-state model and analysis of variance were applied (p ≤ 0.05). Approach time presented differences of the eliminatory Olympic Games (7.3 ± 3.2 s) versus final non-Olympic Games (6.0 ± 2.2s), and the third place playoff Olympic Games (8.1 ± 2.3 s) versus semi-final (6.2 ± 2.4 s) and third place playoff (5.9 ± 2.1 s) of the non-Olympic Games, and the semi-final Olympic Games (8.6 ± 2.3 s) versus eliminatory (6.5 ± 2.3 s), quarter-finals (6.5 ± 1.7 s), semi-final (6.2 ± 2.4 s), repechage (6.2 ± 2.2 s), third place playoff (5.9 ± 2.1 s), and final (6.0 ± 2.0 s) of the non-Olympic Games. Pause time presented differences of the semi-final Olympic Games (6.8 ± 2.1 s) versus eliminatory (5.1 ± 3.1 s). The present data suggest a focus on pacing strategy during championship phases, which mimic the requirements of judo combats.

Differences in Physical Performance According to the Competitive Level in Futsal Players

The purpose of the present study was to describe performance in acceleration capacity, change of direction ability, vertical jump, horizontal jump, repeated sprint ability, and endurance (Yo-Yo Intermittent Recovery Test Level 1) in futsal players, and analyze the differences according to competitive categories or levels. The total sample (n = 40) was divided into three groups depending on the category in which the participants competed: Second Division B (n = 15), Third Division (n = 12) and juniors (n = 13). All the tests were performed with participants’ regular competition shoes and on the usual playing surface, in an indoor pavilion with a floating wood floor. The results of the study did not show significant differences in acceleration capacity (5 and 15 m) or change of direction ability among the different categories. In contrast, significant differences were found among the categories with regard to horizontal jump and vertical jump capacity (p < 0.05); but not in all the variables analyzed. Performance in repeat sprint ability varied significantly among the different categories in 30 m (p < 0.01) but not in 5 m (p > 0.05). The distance covered in the Yo-Yo Intermittent Recovery Test Level 1 by the Second Division B and the Third Division groups was greater than that covered by the junior group. In the light of these results repeated sprint ability and aerobic endurance could be two discriminating qualities of the competitive level among different futsal categories.

The Effectiveness of Land and Water Based Resistance Training on Shoulder Rotator Cuff Strength and Balance of Youth Swimmers

The continuous execution of swimming techniques, supported mainly by the upper limbs, may cause shoulder rotator muscle imbalances, which leads to injuries. The aim of this study was to evaluate and compare the effects of two training programs on strength, balance and endurance of shoulder rotator cuff muscles in youth swimmers. Twenty-five male swimmers were evaluated and randomly divided into two groups - the land group (n = 13), which conducted a conventional dry-land training program with elastic bands, and the water group (n = 12), which conducted a water resistance program. In both groups, the level of strength of the shoulder rotators was evaluated with an isokinetic dynamometer on two occasions (baseline and after 10 weeks) using two protocols: i) three repetitions at 60^o/s; ii) twenty repetitions at 180^o/s. The land group significantly increased the unilateral ratios compared to the water group. The land group also decreased the external rotator levels of muscular fatigue. The dry-land training program conducted proved to be more effective than the one conducted in the water, allowing to reduce the muscle imbalance and to decrease muscle fatigue.

Can Supplementation of Vitamin D Improve Aerobic Capacity in Well Trained Youth Soccer Players?

There is no clear evidence that vitamin D effectively improves physical capacity in high-level athletes. The aim of this study was to confirm that vitamin D supplementation of soccer players during eight-week high-intensity training would have a significant effect on their aerobic capacity. The subjects were divided into two groups: the experimental one that was supplemented with vitamin D (SG, n = 20), and the placebo group (PG, n = 16), not supplemented with vitamin D. All the players were subjected to the same soccer training described as High-Intensity Interval Training (HIIT). The data of the vitamin D level, PWC170, lactate threshold (LT) were collected just before and after the intervention. A significant increase in vitamin D concentration (119%) was observed in the supplemented group, while the non-supplemented group showed a decrease of 8.4%. The studied subjects improved VO2max results by 20% in the SG, and by 13% in the PG. The improvement in velocity at the LT was similar in both groups. Results of this study show that vitamin D can have a positive, though moderate, effect on aerobic performance in players subjected to high-intensity training in the form of small-sided games for 8 weeks.

Using Bilateral Functional and Anthropometric Tests to Define Symmetry in Cross-Country Skiers

The aim of this study was to evaluate the symmetry of anthropometry and muscle function in cross-country skiers and their association to vertical jumping power. Twenty cross-country skiers were recruited (21.7 ± 3.8 yrs, 180.6 ± 7.6 cm, 73.2 ± 7.6 kg). Anthropometric data was obtained using an iDXA scan. VO_2max was determined using the diagonal stride technique on a ski treadmill. Bilateral functional tests for the upper and lower body were the handgrip and standing heel-rise tests. Vertical jump height and power were assessed with a counter movement jump. Percent asymmetry was calculated using a symmetry index and four absolute symmetry index levels. At a group level the upper body was more asymmetrical with regard to lean muscle mass (p = 0.022, d = 0.17) and functional strength (p = 0.019, d = 0.51) than the lower body. At an individual level the expected frequencies for absolute symmetry level indexes showed the largest deviation from zero for the heel-rise test (χ2 = 16.97, p = 0.001), while the leg lean mass deviated the least (χ2 = 0.42, p = 0.517). No relationships were observed between absolute symmetry level indexes of the lower body and counter movement jump performance (p > 0.05). As a group the skiers display a more asymmetrical upper body than lower body regarding muscle mass and strength. Interestingly at the individual level, despite symmetrical lean leg muscle mass the heel-rise test showed the largest asymmetry. This finding indicates a mismatch in muscle function for the lower body.

Seeking Optimal Nutrition for Healthy Body Mass Reduction among Former Athletes

The aim of the study was to investigate the efficacy of 6 week Mediterranean diet or 30% calorie restriction on the fatty acid profile and eicosanoids (hydroxyoctadecadienoi acids and hydroxyeicosatetraenoic acids) concentration. Furthermore, basic biochemical variables such as insulin, glucose, HOMA-IR, and a lipid profile were estimated. The study enrolled 94 Caucasian former athletes aged 20-42, with body height of 179 ± 16.00 cm and body mass of 89.26 ± 13.25 kg who had not been active for at least 5 years. The subjects were randomly assigned to one of the three intervention groups: CR group – the 30% calorie restriction (n = 32), MD group - the Mediterranean diet (n = 34), and C group - a control group (n = 28). The pattern of nutrition was analysed before and after the experiment using the 72 h food diaries. In order to evaluate the effect of diet intervention, the following variables were measured: anthropometrics, basic biochemical variables (insulin, fasting glucose, HOMA-IR, lipid profile), fatty acids and their blood derivatives profiles. The CR group showed significantly lower levels of several biochemical variables, i.e., BMI, total cholesterol LDL, TG, total lipids, insulin and HOMA – IR (p < 0.05). Subjects consuming the MD diet significantly decreased their BMI and reduced the level of total lipids (p < 0.05). We did not find any significant changes in the C group. The analysis of the fatty acid profile revealed that the CR group had a significantly decreased EPA level (p < 0.05). The MD group showed a significantly increased level of the DHA (p < 0.05) and improvement in the omega - 3 index (p < 0.05). Subjects following the MD also showed significantly lower concentrations of 15 - hydroxyicosatetraenoic acid (15-HETE). We did not observe any significant differences between the CR and C groups. Within short time, calorie restriction helps to improve lipid variables and insulin resistance. The MD diet seems to be more advantageous in the decrease of inflammation, but does not improve basic biochemical variables. We can conclude that calorie restriction can be a good choice for former athletes, although EPA and DHA supplementation is needed.

Butterfly Sprint Swimming Technique, Analysis of Somatic and Spatial-Temporal Coordination Variables

The aim of this study was to investigate somatic properties and force production of leg extensor muscles measured in the countermovement jump test (CMJ), as well as to analyse kinematic variables of sprint surface butterfly swimming. Thirty-four male competitive swimmers were recruited with an average age of 19.3 ± 1.83 years. Their average body height (BH) was 183.7 ± 5.93 cm, body fat content 10.8 ± 2.64% and body mass (BM) 78.3 ± 5.0 kg. Length measurements of particular body segments were taken and a counter movement jump (CMJ) as well as an all-out 50 m butterfly speed test were completed. The underwater movements of the swimmers’ bodies were recorded with a digital camera providing side-shots. We registered a significant relationship between body mass (r = 0.46), lean body mass (r = 0.48) and sprint surface butterfly swimming (VSBF). The anaerobic power measured in the CMJ test, total body length (TBL) as well as upper and lower extremity length indices did not influence swimming speed significantly. The temporal entry-kick index (the time ratio between the first kick and arm entry) significantly influenced VSBF (r = -0.45). Similarly, medium power of the coefficient was indicated between a) stroke rate kinematics (SR), b) duration of the first leg kick (LP1), c) air phase duration of arm recovery (Fly-arm), and VSBF (r = 0.40; r = 0.40 and r = 0.41, respectively). The entry-kick temporal index showed that, in the butterfly cycle, an appropriately early executed initial kick when compared to arm entry was associated with a longer arm propulsion phase, which in turn was associated with minimizing resistive gliding phases and enabled relatively longer and less resistive air arm recovery (higher value of the fly-arm index). The higher value of SR kinematic was another important element of the best butterfly results in this study.

Is V̇O2 suppressed during nonapnoeic facial submersion?

The mammalian dive response (DR) is described as oxygen-conserving based on measures of bradycardia, peripheral vasoconstriction, and decreased ventilation (V̇_E). Using a model of simulated diving, this study examined the effect of nonapnoeic facial submersions (NAFS) on oxygen consumption (V̇O₂). 19 participants performed four 2-min NAFS with 8 min of rest between each. Two submersions were performed in 5 °C water, 2 in 25 °C water. Heart rate (HR) was collected using chest strap monitors. A tube connected to the inspired port of a non-rebreathing valve allowed participants to breathe during facial submersion. Expired air was directed to a metabolic cart to determine V̇O₂ and V̇_E. Baseline (BL) HR, V̇O₂, and V̇_E values were determined by the average during the 2 min prior to facial submersion; cold shock response (CSR) values were the maximum during the first 30 s of facial submersion; and NAFS values were the minimum during the last 90 s of facial submersion. A 2-way repeated-measures ANOVA indicated that both HR and V̇_E were greater during the CSR (92.5 ± 3.6 beats/min, 16.3 ± 0.8 L/min) compared with BL (78.9 ± 3.2 beats/min, 8.7 ± 0.4 L/min), while both were decreased from BL during the NAFS (60.0 ± 4.0 beats/min, 6.0 ± 0.4 L/min) (all, p < 0.05). HR_CSR was higher and HR_NAFS lower in 5 °C versus 25 °C water (p < 0.05), while V̇_E was greater in 5 °C conditions (p < 0.05). V̇O₂ exceeded BL during the CSR and decreased below BL during the NAFS (BL: 5.3 ± 0.1, CSR: 9.8 ± 0.4, NAFS: 3.1 ± 0.2 mL·kg^-1·min^-1, p < 0.05). The data illustrate that NAFS alone contributes to the oxygen conservation associated with the human DR.

Aquaticity: A discussion of the term and of how it applies to humans

The relationship between humans and water and the effects on aspects related to human performance has never been studied scientifically. The aim of the current systematic review is to attempt to define the term "aquaticity", present the factors that describe it and reveal the form in which it presents itself in today's society, in order to become a distinct scientific field of study. A systematic review of the literature has been conducted using anecdotal reports from the internet and forums as well as scientific articles and books from databases on issues related to aquatic sports. To the best of our knowledge there are no scientific articles dealing with human's aquaticity. In the current systematic review, four factors have been recognized that are closely related to human aquaticity. Those are related to physical condition in the water, to apnea and ability to immerse, to mental health and to parameters related to body composition. According to our findings, "Aquaticity is the capacity of a terrestrial mammalian organism to function and habitualise in the aquatic environment. The level of aquaticity depends on mental and physical characteristics and can be improved by frequent exposure to the water element". The ideal state of aquaticity is achieved through the activation of the diving reflex, when the human body is totally immersed in water. The development of knowledge regarding the aquatic environment leads humans to an improved state of aquaticity.

Acute apnea swimming: metabolic responses and performance

Competitive swimmers regularly perform apnea series with or without fins as part of their training, but the ergogenic and metabolic repercussions of acute and chronic apnea have not been examined. Therefore, we aimed to investigate the cardiovascular, lactate, arterial oxygen saturation and hormonal responses to acute apnea in relation to performance in male swimmers. According to a randomized protocol, 15 national or regional competitive swimmers were monitored while performing four 100-m freestyle trials, each consisting of four 25-m segments with departure every 30 seconds at maximal speed in the following conditions: with normal frequency breathing with fins (F) and without fins (S) and with complete apnea for the four 25-m segments with (FAp) and without fins (SAp). Heart rate (HR) was measured continuously and arterial oxygen saturation, blood, and saliva samples were assessed after 30 seconds, 3 minutes, and 10 minutes of recovery, respectively. Swimming performance was better with fins than without both with normal frequency breathing and apnea (p < 0.001). Apnea induced no change in lactatemia, but a decrease in arterial oxygen saturation in both SAp and FAp (p < 0.001) was noted and a decrease in HR and swimming performance in SAp (p < 0.01). During apnea without fins, performance alteration was correlated with bradycardia (r = 0.63) and arterial oxygen desaturation (r = -0.57). Saliva dehydroepiandrosterone was increased compared with basal values whatever the trial (p ≤ 0.05), whereas no change was found in saliva cortisol or testosterone. Further studies are necessary to clarify the fin effect on HR and performance during apnea swimming.