Karine Schaal

Parasympathetic Activity and Blood Catecholamine Responses Following a Single Partial-Body Cryostimulation and a Whole-Body Cryostimulation

The aim of this study was to compare the effects of a single whole-body cryostimulation (WBC) and a partial-body cryostimulation (PBC) (i.e., not exposing the head to cold) on indices of parasympathetic activity and blood catecholamines. Two groups of 15 participants were assigned either to a 3-min WBC or PBC session, while 10 participants constituted a control group (CON) not receiving any cryostimulation. Changes in thermal, physiological and subjective variables were recorded before and during the 20-min after each cryostimulation. According to a qualitative statistical analysis, an almost certain decrease in skin temperature was reported for all body regions immediately after the WBC (mean decrease±90% CL, -13.7±0.7°C) and PBC (-8.3±0.3°C), which persisted up to 20-min after the session. The tympanic temperature almost certainly decreased only after the WBC session (-0.32±0.04°C). Systolic and diastolic blood pressures were very likely increased after the WBC session, whereas these changes were trivial in the other groups. In addition, heart rate almost certainly decreased after PBC (-10.9%) and WBC (-15.2%) sessions, in a likely greater proportion for WBC compared to PBC. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely increased after PBC (RMSSD: +54.4%, HF: +138%) and WBC (RMSSD: +85.2%, HF: +632%) sessions without any marked difference between groups. Plasma norepinephrine concentrations were likely to very likely increased after PBC (+57.4%) and WBC (+76.2%), respectively. Finally, cold and comfort sensations were almost certainly altered after WBC and PBC, sensation of discomfort being likely more pronounced after WBC than PBC. Both acute cryostimulation techniques effectively stimulated the autonomic nervous system (ANS), with a predominance of parasympathetic tone activation. The results of this study also suggest that a whole-body cold exposure induced a larger stimulation of the ANS compared to partial-body cold exposure.

Whole-Body Cryostimulation Limits Overreaching in Elite Synchronized Swimmers

INTRODUCTION Elite athletes frequently undergo periods of intensified training (IT) within their normal training program. These periods can lead athletes into functional overreaching, characterized by high perceived fatigue, impaired sleep, and performance. Because whole-body cryostimulation (WBC) has been proven to be an effective recovery method in the short term (<76 h), we investigated whether daily WBC sessions during IT could prevent exercise and sleep-related signs of overreaching. METHODS After a normal training week (BASE), 10 elite synchronized swimmers performed two 2-wk IT periods in a randomized crossover fashion using WBC daily (ITWBC) or not (ITCON), separated by 9 d of light training. Swim time trials (400 m) were performed at BASE and after each IT to quantify blood lactate ([La]B), HR (HR400), salivary alpha amylase ([α-amylase]s400), and cortisol ([cortisol]s400) responses. Swimmers wore a wrist actigraph nightly to monitor sleep patterns. RESULTS Swim speed (400 m), [La]B400, and [α-amylase]s400 decreased from BASE to ITCON, although no significant changes were found after ITWBC. Decreased swim speed was correlated to decreased HR400 and [cortisol]s400. During ITCON, significant decreases in actual sleep duration (-21 ± 7 min) and sleep efficiency (-1.9% ± 0.8%) were observed, with increased sleep latency (+11 ± 5 min) and fatigue compared with BASE, although these variables did not change during ITWBC. Using a qualitative statistical analysis, we observed that daily WBC use resulted in a 98%, 59%, 66%, and 78% chance of preserving these respective variables compared with ITCON. CONCLUSION WBC use during IT helped mitigate the signs of functional overreaching observed during ITCON, such as reduced sleep quantity, increased fatigue, and impaired exercise capacity. These results support the daily use of WBC by athletes seeking to avoid functional overreaching during key periods of competition preparation.

Reduced Catecholamine Response to Exercise in Amenorrheic Athletes

PURPOSE We examined the catecholamine response to exercise in five eumenorrheic (EU) and five amenorrheic (AM) athletes, matched by age (mean ± SEM: EU = 29.8 ± 2.5 yr and AM = 31.0 ± 4.3 yr) and running volume (EU = 56.4 ± 8.1 km·wk(-1) and AM = 61.5 ± 6.4 km·wk(-1)). METHODS Subjects performed a maximal treadmill test followed by a 30-min recovery and then a submaximal running test, consisting of 4-min stages at 60%, 70%, and 80% and 15 min at 85% of peak oxygen consumption (VO(2peak)). Blood was drawn after each stage to measure glucose, lactate, epinephrine, norepinephrine, and cortisol concentrations. HR, blood pressure, and rate of perceived exertion were also measured at each stage. RESULTS There were no differences between groups in body composition or VO(2peak) (EU = 57.3 ± 2.3 mL·kg(-1)·min(-1) and AM = 54.1 ± 1.2 mL·kg(-1)·min(-1). Resting HR and mean arterial pressure were significantly (P ≤ 0.05) lower in AM. Norepinephrine was lower in AM at 70%, 80%, 85%, and 100% of VO(2peak) (EU = 7784.5 ± 582.9 pg·mL(-1) and AM = 3626.1 ± 271.4 pg·mL(-1) at VO(2peak)). Epinephrine (EU = 1470.3 ± 275.1 pg·mL(-1) and AM = 416.9 ± 67.5 pg·mL(-1)) and blood lactate (EU = 10.1 ± 1.2 mmol·L(-1) and AM = 6.7 ± 0.9 mmol·L(-1)) were lower at VO(2peak) in AM. CONCLUSIONS Our results demonstrate a reduced adrenergic response to intense exercise in AM athletes as indicated by reduced blood lactate and catecholamine concentrations. A suppressed catecholamine response could decrease performance by reducing the sympathetic drive essential for the cardiovascular and metabolic adjustments needed to maintain high intensities of exercise.

Maximal exercise limitation in functionally overreached triathletes: role of cardiac adrenergic stimulation

Functional overreaching (F-OR) induced by heavy load endurance training programs has been associated with reduced heart rate values both at rest and during exercise. Because this phenomenon may reflect an impairment of cardiac response, this research was conducted to test this hypothesis. Thirty-five experienced male triathletes were tested (11 control and 24 overload subjects) before overloading (Pre), immediately after overloading (Mid), and after a 2-wk taper period (Post). Physiological responses were assessed during an incremental cycling protocol to volitional exhaustion, including catecholamines release, oxygen uptake (V̇o2), arteriovenous O2 difference, cardiac output (Q̇), and systolic (SBP) and diastolic blood pressure (DBP). Twelve subjects of the overload group developed signs of F-OR at Mid (decreased performance with concomitant high perceived fatigue), while 12 others did not [acute fatigue group (AF)]. V̇o2max was reduced only in F-OR subjects at Mid. Lower Q̇ and SBP values with greater arteriovenous O2 difference were reported in F-OR subjects at all exercising intensities, while no significant change was observed in the control and AF groups. A concomitant decrease in epinephrine excretion was reported only in the F-OR group. All values returned to baseline at Post. Following an overload endurance training program leading to F-OR, the cardiac response to exhaustive exercise is transiently impaired, possibly due to reduced epinephrine excretion. This finding is likely to explain the complex process of underperformance syndrome experienced by F-OR endurance athletes during heavy load programs.

Success and Decline: Top 10 Tennis Players Follow a Biphasic Course

INTRODUCTION The victory percentages for tennis players who entered the top 10 women and men rankings show various evolutions related to age and time since 1968. METHODS The study analyzed the careers of all top 10 players: 97 women (50,933 matches) and 144 men (92,450 matches). For each player, we describe a biphasic performance course. Two generations were compared: the first one (G1), including players who started their professional career before 1985, and the second one (G2), with players starting after 1985. RESULTS The average career length is 16.1 ± 3.8 yr for the top 10 men and 15.8 ± 4.4 yr for women. Compared with G1 players, G2 players begin earlier (women = 1.3 yr, men = 0.8 yr), but career length remains the same. An exponential model describes the time course of the victory percentage with a great similarity for both genders. Using this equation, the peak victory rate reaches 82.5% at 21.5 yr for number 1 (no. 1) women and 78.5% at 23.7 yr for no. 1 men, showing a greater precocity and earlier decline in women. Finally, the area under the curve shows a potential that is 22.8% (men) to 56.8% (women) larger for the no. 1 players as compared with all other numbers 2-10. CONCLUSIONS Tennis players in the top 10 show a biphasic career. Women reach their highest level earlier than men, consistent with their more precocious biological development. For the current generation, the peak performance tends toward a younger age than the first generation. We show how to precisely quantify and compare tennis performances using indicators that follow the trends of development and aging and demonstrate that precocity does not provide a larger victory potential.

Secular trend: morphology and performance

In a context of morphological expansion of the general population, how do athletes follow such a pattern of anthropometric growth? Is there any relation to performance? Biometric data including mass, height, body mass index (BMI) and age were collected for 50,376 American athletes representing 249,336 annual performers playing in professional baseball, football, ice hockey and basketball. Distributions by mass in National Football League (NFL) players are described by periods. Field goals have been studied in relation to players’ height in the National Basketball Association (NBA). Between 1871 and 2011, athletes from the four sports have increased significantly in mass, height and BMI, following a multi-exponential function series. Consequently, biometric differences between athletes and the general population are increasing gradually. Changes in the mass distribution within the NFL show the emergence of a biometrical specificity in relation to the field position. At the professional level, performance remains structured around precise biometric values. In the NBA, a height-attractor at 201.3 ± 6.3 cm for the best scorers is invariant, regardless of the level of play. These results suggest that laws of growth and biometrics drive high-level sport and organise performance around the specific constraint of each field position. Discrepancies between some mass and height developments question the (disproportionate) large mass increase (relative to the height increase) during the 1980s and 1990s.

Head Exposure to Cold during Whole-Body Cryostimulation: Influence on Thermal Response and Autonomic Modulation

Recent research on whole-body cryotherapy has hypothesized a major responsibility of head cooling in the physiological changes classically reported after a cryostimulation session. The aim of this experiment was to verify this hypothesis by studying the influence of exposing the head to cold during whole-body cryostimulation sessions, on the thermal response and the autonomic nervous system (ANS). Over five consecutive days, two groups of 10 participants performed one whole-body cryostimulation session daily, in one of two different systems; one exposing the whole-body to cold (whole-body cryostimulation, WBC), and the other exposing the whole-body except the head (partial-body cryostimulation, PBC).10 participants constituted a control group (CON) not receiving any cryostimulation. In order to isolate the head-cooling effect on recorded variables, it was ensured that the WBC and PBC systems induced the same decrease in skin temperature for all body regions (mean decrease over the 5 exposures: -8.6°C±1.3°C and -8.3±0.7°C for WBC and PBC, respectively), which persisted up to 20-min after the sessions (P20). The WBC sessions caused an almost certain decrease in tympanic temperature from Pre to P20 (-0.28 ±0.11°C), while it only decreased at P20 (-0.14±0.05°C) after PBC sessions. Heart rate almost certainly decreased after PBC (-8.6%) and WBC (-12.3%) sessions. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely to almost certainly increased after PBC (RMSSD:+49.1%, HF: +123.3%) and WBC (RMSSD: +38.8%, HF:+70.3%). Plasma norepinephrine concentration was likely increased in similar proportions after PBC and WBC, but only after the first session. Both cryostimulation techniques stimulated the ANS with a predominance of parasympathetic tone activation from the first to the fifth session and in slightly greater proportion with WBC than PBC. The main result of this study indicates that the head exposure to cold during whole-body cryostimulation may not be the main factor responsible for the effects of cryostimulation on the ANS.