ABSTRACT This study aims to identify the potential bias of the relative age effect (RAE) in Frenc... more ABSTRACT This study aims to identify the potential bias of the relative age effect (RAE) in French alpine skiers and to propose a mathematical correction adjustment for such a bias. All performances and birthdates of skiers on the national and international circuit were collected from the 2004 up to 2019. A goodness-of-fit chi-square test and the residuals were used to study the distribution of birth trimesters in youth competitors. A linear relationship between the distribution of performances and the months obtains a calibration coefficient allowing to rebalance the performance by considering the effect of RAE. Individuals born at the beginning of the year are over-represented in the elite young selections in all disciplines for both genders. A coefficient based on the relationship between month of birth and performance adjusts individual performance and cancels out the effect of RAE. The results show that RAE is present in French alpine skiing. We present a method allowing to consider the effect of the RAE in the performances realized in each gender and discipline. This method allows coaches to have a more objective opinion on performance and to reduce selection bias.
Alpine ski racers require diverse physical capabilities. While enhanced force production is consi... more Alpine ski racers require diverse physical capabilities. While enhanced force production is considered key to high-level skiing, its relevance is convoluted. The aims of this study were to i) clarify the association between performance path length and velocity, ii) test the importance of radial force, and iii) explore the contribution of force magnitude and orientation to turn performance. Ski athletes (N = 15) were equipped with ski-mounted force plates and a global navigation satellite system to compute the following variables over 14 turns: path length (L), velocity normalized energy dissipation [Δemech/vin], radial force [Fr], total force (both limbs [Ftot], the outside limb, and the difference between limbs), and a ratio of force application (RF = Fr/Ftot). Data were course-averaged or separated into sectional turn groupings, averaged, and entered into stepped correlation and regression models. Our results support Δemech/vin as a discriminative performance factor (R2 = 0.50–0.7...
This study investigated changes in heart rate variability (HRV) in elite Nordic-skiers to charact... more This study investigated changes in heart rate variability (HRV) in elite Nordic-skiers to characterize different types of "fatigue" in 27 men and 30 women surveyed from 2004 to 2008. R-R intervals were recorded at rest during 8 min supine (SU) followed by 7 min standing (ST). HRV parameters analysed were powers of low (LF), high (HF) frequencies, (LF+HF) (ms(2)) and heart rate (HR, bpm). In the 1 063 HRV tests performed, 172 corresponded to a "fatigue" state and the first were considered for analysis. 4 types of "fatigue" (F) were identified: 1. F(HF(-)LF(-))SU_ST for 42 tests: decrease in LFSU (- 46%), HFSU (- 70%), LFST (- 43%), HFST (- 53%) and increase in HRSU (+ 15%), HRST (+ 14%). 2. F(LF(+) SULF(-) ST) for 8 tests: increase in LFSU (+ 190%) decrease in LFST (- 84%) and increase in HRST (+ 21%). 3. F(HF(-) SUHF(+) ST) for 6 tests: decrease in HFSU (- 72%) and increase in HFST (+ 501%). 4. F(HF(+) SU) for only 1 test with an increase in HFSU (+ 2161%) and decrease in HRSU (- 15%). Supine and standing HRV patterns were independently modified by "fatigue". 4 "fatigue"-shifted HRV patterns were statistically sorted according to differently paired changes in the 2 postures. This characterization might be useful for further understanding autonomic rearrangements in different "fatigue" conditions.
Estimating the potential of alpine skiers is an unresolved question, especially because of the co... more Estimating the potential of alpine skiers is an unresolved question, especially because of the complexity of sports performance. We developed a potential estimation model based solely on the evolution of performance as a function of age. A bayesian mixed model allowed to estimate the potential curve and the age at peak performance for the population (24.81 ± 0.2) and for each individual as the uncertainty around this curve. With Gaussian mixtures, we identified among all the estimates four types of curves, clustered according to the performance level and the progression per age. Relying on the uncertainty calculated on the progression curve the model created also allow to estimate a score and an uncertainty associated with each cluster for all individuals. The results allows to: i) describe and explain the relationship between age and performance in alpine skiing from a species point of view (at 0.87%) and ii) to provide to sport staffs the estimation of the potential of each indivi...
SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate,... more SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
In elite endurance sport, the goal of training is to optimally distribute intensity and load to i... more In elite endurance sport, the goal of training is to optimally distribute intensity and load to improve aerobic capacity [11, 35], and it is known that this distribution has to be individualised [11]. Some training periods are characterised by very high training load (TL) aimed at the maximal stress supportable by the athlete, followed by periods of lighter TL in order to induce supercompensation. The monitoring of fitness and fatigue is essential, but it remains difficult to diagnose training-induced fatigue. It is complex to differentiate the fatigue instrumental in enhanced physiological adaptations from the fatigue that overtakes the recovery capacities of the athlete and leads to nonfunctional overreaching (NFOR) or overtraining (OTS) [20]. Heart rate variability (HRV) has been presented as a promising tool to differentiate fatigue states, and many studies have reported the influence of the training components (intensity and volume) on HRV due to a modulation in autonomic nervo...
In jumping, countermovement increases net propulsive force and improves performance. We aimed to ... more In jumping, countermovement increases net propulsive force and improves performance. We aimed to test whether this countermovement effect is velocity specific and examine the degree to which this varies between athletes, sports or performance levels. Force-velocity profiles were compiled in high-level skiers (N= 23) and sprinters (N= 30), with their performance represented in their overall world ranking and season-best 100 m time, respectively. Different ratios between force-velocity variables were computed from squat and countermovement jumps (smaller = less effect): jump height (CRh ), maximum power (CRP ), force (CRF ), and velocity (CRv ). Countermovement effect differed per velocity (inverse relationship between CRF and CRv, rs = −0.74, p< .001), and variation force-velocity profiles with countermovement. Skiers exhibited smaller CRF (rrb = −0.675, p< .001), sprinters smaller CRv (rrb = 0.426, p= .008), and “moderate” velocity conditions did not differentiate groups (CRP ...
The purpose of this study was to measure the difference in normal force under both feet during al... more The purpose of this study was to measure the difference in normal force under both feet during alpine skiing giant slalom turns. Eleven experienced alpine skiers performed a giant slalom course at race intensity. All trials were recorded synchronously using a video camera and a plantar pressure measuring system. The mean force on the grouped two feet varied from 0.7 BW at the start of a turn to 1.5 BW during the steering phase of a turn performed in a steep slope condition. When skiing on FLAT slope condition, it reached only 1.3 BW. Results also showed that the outside foot receives significantly more pressure than the inside foot during the entire turn except the initiation phase. This last finding is not affected by slope steepness.
International Journal of Sports Physiology and Performance
Purpose: The purpose of this study was to determine the test–retest reliability of the 80s-slide-... more Purpose: The purpose of this study was to determine the test–retest reliability of the 80s-slide-test in well-trained alpine ski racers. Methods: The sample consisted of 8 well-trained alpine ski racers (age = 17.8 [0.7] y old; height = 1.80 [0.09] m; body mass = 72.1 [9.5] kg) who performed a lab-based maximal graded test on cycle ergometer and three 80s-slide-tests in 4 separate sessions. The 80s-slide-test consisting of maximal push-offs performed for 80s on a 8-ft slide board. Oxygen uptake () and heart rate (HR) were recorded continuously. Blood lactate ([La]b) was determined immediately prerun, followed by 3 minutes postrun. Three minutes after the completion of the session, the subjects were asked to indicate their rate of perceived exertion using Borg scale ranging from 6 to 20. Total and every 10s mean push-offs number were assessed by camera. Typical errors of measurement, intraclass correlation coefficients, and smallest worthwhile change were calculated. Results: The 80s...
Alpine ski racers require diverse physical capabilities. While enhanced force production is consi... more Alpine ski racers require diverse physical capabilities. While enhanced force production is considered key to high-level skiing, its relevance is convoluted. The aims of this study were i) clarify the association between performance path length and velocity, ii) test the importance of radial force, and iii) to explore the contribution of force magnitude and orientation to turn performance. Ski athletes (N=15) were equipped with ski-mounted force plates and a global navigation satellite system to compute the following variables over 14 turns: path length (L), velocity normalized energy dissipation [∆emech/vin], radial force [Fr], total force (both limbs [Ftot], the outside limb, and the difference between limbs) and a ratio of force application (RF=Fr /Ftot). Data were course-averaged or separated into sectional turn groupings, averaged, and entered into stepped correlation and regression models. Our results support ∆emech/vin as a discriminative performance factor (R2=0.46–71, p<...
We aimed to analyse the relationship between training load/intensity and different heart rate var... more We aimed to analyse the relationship between training load/intensity and different heart rate variability (HRV) fatigue patterns in 57 elite Nordic-skiers. 1063 HRV tests were performed during 5 years. R-R intervals were recorded in resting supine (SU) and standing (ST) positions. Heart rate, low (LF), high (HF) frequency powers of HRV were determined. Training volume, training load (TL, a.u.) according to ventilatory threshold 1 (VT1) and VT2 were measured in zones I≤VT1; VT1VT2, IV for strength. TL was performed at 81.6±3.5% in zone I, 0.9±0.9% in zone II, 5.0±3.6% in zone III, 11.6±6.3% in zone IV. 172 HRV tests matched a fatigue state and four HRV fatigue patterns (F) were statistically characterized as F(HF-LF-)SU_ST for 121 tests, F(LF+SULF-ST) for 18 tests, F(HF-SUHF+ST) for 26 tests and F(HF+SU) for 7 tests. The occurrence of fatigue states increased substantially with the part of altitude training time (r2=0.52, p<0.001). This study evidenced that there is no causal rela...
Bottollier, V, Coulmy, N, Le Quellec, L, and Prioux, J. Energy demands in well-trained alpine ski... more Bottollier, V, Coulmy, N, Le Quellec, L, and Prioux, J. Energy demands in well-trained alpine ski racers during different duration of slalom and giant slalom runs. J Strength Cond Res 34(8): 2156-2164, 2020-The purpose of this study was to investigate the energy demands of different duration slalom (SL) and giant slalom (GS) events in well-trained alpine ski racers. Eight well-trained alpine ski racers (age: 18.2 ± 0.8 years; stature: 1.72 ± 0.10 m; body mass: 65.8 ± 12.0 kg) performed an incremental laboratory test on cycle ergometer and 4 standardized alpine ski runs: short (ST) and long (LG) versions of SL and GS (SLST, SLLG, GSST, and GSLG). Oxygen uptake (V[Combining Dot Above]O2) and heart rate (HR) were recorded continuously in all conditions. Blood lactate ([La]) was determined immediately before run and 3 and 5 minutes after run ([La]peak). The contribution of aerobic, glycolytic, and phosphagen energy systems was estimated. The aerobic system was the primary energy system involved in GSST (43.9 ± 5.7%) and GSLG (48.5 ± 2.5%). No significant difference in the contribution of aerobic and glycolytic systems was observed in SLST and SLLG. [La]peak was higher in SLLG (11.10 ± 2.41 mmol·L) than in GSST (8.01 ± 2.01 mmol·L). There was no difference in oxygen uptake peak between GSST and GSLG. Energetic training goals should focus on the improvement of both aerobic, glycolytic, and phosphagen systems for alpine ski racers who perform SL and GS. Giant slalom specialists might benefit from emphasizing the improvement of the aerobic system, without neglecting other systems.
To analyze the effects of different training strategies (i.e., mainly intensity distribution) dur... more To analyze the effects of different training strategies (i.e., mainly intensity distribution) during living high - training low (LHTL) between elite cross-country skiers and Nordic-combined athletes. 12 cross-country skiers (XC) (7 men, 5 women), and 8 male Nordic combined (NC) of the French national teams were monitored during 15 days of LHTL. The distribution of training at low-intensity (LIT), below the first ventilatory threshold (VT1), was 80% and 55% in XC and NC respectively. Daily, they filled a questionnaire of fatigue, and performed a heart rate variability (HRV) test. Prior (Pre) and immediately after (Post), athletes performed a treadmill incremental running test for determination of O and O at the second ventilatory threshold ( O), a field roller-skiing test with blood lactate ([La-]) assessment. The training volume was in XC and NC, respectively: at LIT: 45.9 ± 6.4 vs. 23.9 ± 2.8 h ( < 0.001), at moderate intensity: 1.9 ± 0.5 vs. 3.0 ± 0.4 h, ( < 0.001), at high ...
To analyze if live high-train low (LHTL) effectiveness is improved when daily training is guided ... more To analyze if live high-train low (LHTL) effectiveness is improved when daily training is guided by heart rate variability (HRV). Twenty-four elite Nordic skiers took part in a 15-day LHTL study and were randomized into a HRV-guided training hypoxic group (H-HRV, n = 9, sleeping in normobaric hypoxia, FiO = 15.0%) and two predefined training groups sleeping either in hypoxia (H, n = 9, FiO = 15.0%) or normoxia (N, n = 6). HRV and training loads (TL) were recorded daily. Prior (Pre), one (Post-1), and 21 days (Post-21) following LHTL, athletes performed a 10-km roller-ski test, and a treadmill test for determination of [Formula: see text] was performed at Pre and Post-1. Some HRV parameters measured in supine position were different between H-HRV and H: low and high (HF) frequency power in absolute (ms) (16.0 ± 35.1 vs. 137.0 ± 54.9%, p = 0.05) and normalized units (- 3.8 ± 10.1 vs. 53.0 ± 19.5%, p = 0.02), HF(nu) (6.3 ± 6.8 vs. - 13.7 ± 8.0%, p = 0.03) as well as heart rate (3.7 ± 6...
ABSTRACT This study aims to identify the potential bias of the relative age effect (RAE) in Frenc... more ABSTRACT This study aims to identify the potential bias of the relative age effect (RAE) in French alpine skiers and to propose a mathematical correction adjustment for such a bias. All performances and birthdates of skiers on the national and international circuit were collected from the 2004 up to 2019. A goodness-of-fit chi-square test and the residuals were used to study the distribution of birth trimesters in youth competitors. A linear relationship between the distribution of performances and the months obtains a calibration coefficient allowing to rebalance the performance by considering the effect of RAE. Individuals born at the beginning of the year are over-represented in the elite young selections in all disciplines for both genders. A coefficient based on the relationship between month of birth and performance adjusts individual performance and cancels out the effect of RAE. The results show that RAE is present in French alpine skiing. We present a method allowing to consider the effect of the RAE in the performances realized in each gender and discipline. This method allows coaches to have a more objective opinion on performance and to reduce selection bias.
Alpine ski racers require diverse physical capabilities. While enhanced force production is consi... more Alpine ski racers require diverse physical capabilities. While enhanced force production is considered key to high-level skiing, its relevance is convoluted. The aims of this study were to i) clarify the association between performance path length and velocity, ii) test the importance of radial force, and iii) explore the contribution of force magnitude and orientation to turn performance. Ski athletes (N = 15) were equipped with ski-mounted force plates and a global navigation satellite system to compute the following variables over 14 turns: path length (L), velocity normalized energy dissipation [Δemech/vin], radial force [Fr], total force (both limbs [Ftot], the outside limb, and the difference between limbs), and a ratio of force application (RF = Fr/Ftot). Data were course-averaged or separated into sectional turn groupings, averaged, and entered into stepped correlation and regression models. Our results support Δemech/vin as a discriminative performance factor (R2 = 0.50–0.7...
This study investigated changes in heart rate variability (HRV) in elite Nordic-skiers to charact... more This study investigated changes in heart rate variability (HRV) in elite Nordic-skiers to characterize different types of "fatigue" in 27 men and 30 women surveyed from 2004 to 2008. R-R intervals were recorded at rest during 8 min supine (SU) followed by 7 min standing (ST). HRV parameters analysed were powers of low (LF), high (HF) frequencies, (LF+HF) (ms(2)) and heart rate (HR, bpm). In the 1 063 HRV tests performed, 172 corresponded to a "fatigue" state and the first were considered for analysis. 4 types of "fatigue" (F) were identified: 1. F(HF(-)LF(-))SU_ST for 42 tests: decrease in LFSU (- 46%), HFSU (- 70%), LFST (- 43%), HFST (- 53%) and increase in HRSU (+ 15%), HRST (+ 14%). 2. F(LF(+) SULF(-) ST) for 8 tests: increase in LFSU (+ 190%) decrease in LFST (- 84%) and increase in HRST (+ 21%). 3. F(HF(-) SUHF(+) ST) for 6 tests: decrease in HFSU (- 72%) and increase in HFST (+ 501%). 4. F(HF(+) SU) for only 1 test with an increase in HFSU (+ 2161%) and decrease in HRSU (- 15%). Supine and standing HRV patterns were independently modified by "fatigue". 4 "fatigue"-shifted HRV patterns were statistically sorted according to differently paired changes in the 2 postures. This characterization might be useful for further understanding autonomic rearrangements in different "fatigue" conditions.
Estimating the potential of alpine skiers is an unresolved question, especially because of the co... more Estimating the potential of alpine skiers is an unresolved question, especially because of the complexity of sports performance. We developed a potential estimation model based solely on the evolution of performance as a function of age. A bayesian mixed model allowed to estimate the potential curve and the age at peak performance for the population (24.81 ± 0.2) and for each individual as the uncertainty around this curve. With Gaussian mixtures, we identified among all the estimates four types of curves, clustered according to the performance level and the progression per age. Relying on the uncertainty calculated on the progression curve the model created also allow to estimate a score and an uncertainty associated with each cluster for all individuals. The results allows to: i) describe and explain the relationship between age and performance in alpine skiing from a species point of view (at 0.87%) and ii) to provide to sport staffs the estimation of the potential of each indivi...
SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate,... more SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
In elite endurance sport, the goal of training is to optimally distribute intensity and load to i... more In elite endurance sport, the goal of training is to optimally distribute intensity and load to improve aerobic capacity [11, 35], and it is known that this distribution has to be individualised [11]. Some training periods are characterised by very high training load (TL) aimed at the maximal stress supportable by the athlete, followed by periods of lighter TL in order to induce supercompensation. The monitoring of fitness and fatigue is essential, but it remains difficult to diagnose training-induced fatigue. It is complex to differentiate the fatigue instrumental in enhanced physiological adaptations from the fatigue that overtakes the recovery capacities of the athlete and leads to nonfunctional overreaching (NFOR) or overtraining (OTS) [20]. Heart rate variability (HRV) has been presented as a promising tool to differentiate fatigue states, and many studies have reported the influence of the training components (intensity and volume) on HRV due to a modulation in autonomic nervo...
In jumping, countermovement increases net propulsive force and improves performance. We aimed to ... more In jumping, countermovement increases net propulsive force and improves performance. We aimed to test whether this countermovement effect is velocity specific and examine the degree to which this varies between athletes, sports or performance levels. Force-velocity profiles were compiled in high-level skiers (N= 23) and sprinters (N= 30), with their performance represented in their overall world ranking and season-best 100 m time, respectively. Different ratios between force-velocity variables were computed from squat and countermovement jumps (smaller = less effect): jump height (CRh ), maximum power (CRP ), force (CRF ), and velocity (CRv ). Countermovement effect differed per velocity (inverse relationship between CRF and CRv, rs = −0.74, p< .001), and variation force-velocity profiles with countermovement. Skiers exhibited smaller CRF (rrb = −0.675, p< .001), sprinters smaller CRv (rrb = 0.426, p= .008), and “moderate” velocity conditions did not differentiate groups (CRP ...
The purpose of this study was to measure the difference in normal force under both feet during al... more The purpose of this study was to measure the difference in normal force under both feet during alpine skiing giant slalom turns. Eleven experienced alpine skiers performed a giant slalom course at race intensity. All trials were recorded synchronously using a video camera and a plantar pressure measuring system. The mean force on the grouped two feet varied from 0.7 BW at the start of a turn to 1.5 BW during the steering phase of a turn performed in a steep slope condition. When skiing on FLAT slope condition, it reached only 1.3 BW. Results also showed that the outside foot receives significantly more pressure than the inside foot during the entire turn except the initiation phase. This last finding is not affected by slope steepness.
International Journal of Sports Physiology and Performance
Purpose: The purpose of this study was to determine the test–retest reliability of the 80s-slide-... more Purpose: The purpose of this study was to determine the test–retest reliability of the 80s-slide-test in well-trained alpine ski racers. Methods: The sample consisted of 8 well-trained alpine ski racers (age = 17.8 [0.7] y old; height = 1.80 [0.09] m; body mass = 72.1 [9.5] kg) who performed a lab-based maximal graded test on cycle ergometer and three 80s-slide-tests in 4 separate sessions. The 80s-slide-test consisting of maximal push-offs performed for 80s on a 8-ft slide board. Oxygen uptake () and heart rate (HR) were recorded continuously. Blood lactate ([La]b) was determined immediately prerun, followed by 3 minutes postrun. Three minutes after the completion of the session, the subjects were asked to indicate their rate of perceived exertion using Borg scale ranging from 6 to 20. Total and every 10s mean push-offs number were assessed by camera. Typical errors of measurement, intraclass correlation coefficients, and smallest worthwhile change were calculated. Results: The 80s...
Alpine ski racers require diverse physical capabilities. While enhanced force production is consi... more Alpine ski racers require diverse physical capabilities. While enhanced force production is considered key to high-level skiing, its relevance is convoluted. The aims of this study were i) clarify the association between performance path length and velocity, ii) test the importance of radial force, and iii) to explore the contribution of force magnitude and orientation to turn performance. Ski athletes (N=15) were equipped with ski-mounted force plates and a global navigation satellite system to compute the following variables over 14 turns: path length (L), velocity normalized energy dissipation [∆emech/vin], radial force [Fr], total force (both limbs [Ftot], the outside limb, and the difference between limbs) and a ratio of force application (RF=Fr /Ftot). Data were course-averaged or separated into sectional turn groupings, averaged, and entered into stepped correlation and regression models. Our results support ∆emech/vin as a discriminative performance factor (R2=0.46–71, p<...
We aimed to analyse the relationship between training load/intensity and different heart rate var... more We aimed to analyse the relationship between training load/intensity and different heart rate variability (HRV) fatigue patterns in 57 elite Nordic-skiers. 1063 HRV tests were performed during 5 years. R-R intervals were recorded in resting supine (SU) and standing (ST) positions. Heart rate, low (LF), high (HF) frequency powers of HRV were determined. Training volume, training load (TL, a.u.) according to ventilatory threshold 1 (VT1) and VT2 were measured in zones I≤VT1; VT1VT2, IV for strength. TL was performed at 81.6±3.5% in zone I, 0.9±0.9% in zone II, 5.0±3.6% in zone III, 11.6±6.3% in zone IV. 172 HRV tests matched a fatigue state and four HRV fatigue patterns (F) were statistically characterized as F(HF-LF-)SU_ST for 121 tests, F(LF+SULF-ST) for 18 tests, F(HF-SUHF+ST) for 26 tests and F(HF+SU) for 7 tests. The occurrence of fatigue states increased substantially with the part of altitude training time (r2=0.52, p<0.001). This study evidenced that there is no causal rela...
Bottollier, V, Coulmy, N, Le Quellec, L, and Prioux, J. Energy demands in well-trained alpine ski... more Bottollier, V, Coulmy, N, Le Quellec, L, and Prioux, J. Energy demands in well-trained alpine ski racers during different duration of slalom and giant slalom runs. J Strength Cond Res 34(8): 2156-2164, 2020-The purpose of this study was to investigate the energy demands of different duration slalom (SL) and giant slalom (GS) events in well-trained alpine ski racers. Eight well-trained alpine ski racers (age: 18.2 ± 0.8 years; stature: 1.72 ± 0.10 m; body mass: 65.8 ± 12.0 kg) performed an incremental laboratory test on cycle ergometer and 4 standardized alpine ski runs: short (ST) and long (LG) versions of SL and GS (SLST, SLLG, GSST, and GSLG). Oxygen uptake (V[Combining Dot Above]O2) and heart rate (HR) were recorded continuously in all conditions. Blood lactate ([La]) was determined immediately before run and 3 and 5 minutes after run ([La]peak). The contribution of aerobic, glycolytic, and phosphagen energy systems was estimated. The aerobic system was the primary energy system involved in GSST (43.9 ± 5.7%) and GSLG (48.5 ± 2.5%). No significant difference in the contribution of aerobic and glycolytic systems was observed in SLST and SLLG. [La]peak was higher in SLLG (11.10 ± 2.41 mmol·L) than in GSST (8.01 ± 2.01 mmol·L). There was no difference in oxygen uptake peak between GSST and GSLG. Energetic training goals should focus on the improvement of both aerobic, glycolytic, and phosphagen systems for alpine ski racers who perform SL and GS. Giant slalom specialists might benefit from emphasizing the improvement of the aerobic system, without neglecting other systems.
To analyze the effects of different training strategies (i.e., mainly intensity distribution) dur... more To analyze the effects of different training strategies (i.e., mainly intensity distribution) during living high - training low (LHTL) between elite cross-country skiers and Nordic-combined athletes. 12 cross-country skiers (XC) (7 men, 5 women), and 8 male Nordic combined (NC) of the French national teams were monitored during 15 days of LHTL. The distribution of training at low-intensity (LIT), below the first ventilatory threshold (VT1), was 80% and 55% in XC and NC respectively. Daily, they filled a questionnaire of fatigue, and performed a heart rate variability (HRV) test. Prior (Pre) and immediately after (Post), athletes performed a treadmill incremental running test for determination of O and O at the second ventilatory threshold ( O), a field roller-skiing test with blood lactate ([La-]) assessment. The training volume was in XC and NC, respectively: at LIT: 45.9 ± 6.4 vs. 23.9 ± 2.8 h ( < 0.001), at moderate intensity: 1.9 ± 0.5 vs. 3.0 ± 0.4 h, ( < 0.001), at high ...
To analyze if live high-train low (LHTL) effectiveness is improved when daily training is guided ... more To analyze if live high-train low (LHTL) effectiveness is improved when daily training is guided by heart rate variability (HRV). Twenty-four elite Nordic skiers took part in a 15-day LHTL study and were randomized into a HRV-guided training hypoxic group (H-HRV, n = 9, sleeping in normobaric hypoxia, FiO = 15.0%) and two predefined training groups sleeping either in hypoxia (H, n = 9, FiO = 15.0%) or normoxia (N, n = 6). HRV and training loads (TL) were recorded daily. Prior (Pre), one (Post-1), and 21 days (Post-21) following LHTL, athletes performed a 10-km roller-ski test, and a treadmill test for determination of [Formula: see text] was performed at Pre and Post-1. Some HRV parameters measured in supine position were different between H-HRV and H: low and high (HF) frequency power in absolute (ms) (16.0 ± 35.1 vs. 137.0 ± 54.9%, p = 0.05) and normalized units (- 3.8 ± 10.1 vs. 53.0 ± 19.5%, p = 0.02), HF(nu) (6.3 ± 6.8 vs. - 13.7 ± 8.0%, p = 0.03) as well as heart rate (3.7 ± 6...
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