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Effect of Altitude Training on Basketball Performance
Abstract
The aim of this study was to investigate whether adding hypoxia to 4 weeks of repeated sprint and high-intensity training improved explosive muscular power, aerobic performance and repeated sprint ability in 3x3 basketball players. Eleven well trained female basketball players, were randomly assigned to a hypoxia (H) (n = 5; age: 20.0 ± 1.6; height: 169.4 ± 4.6; body mass: 76.9 ± 6.5; haemoglobin: 135.8 ± 4.1) or control (C) group (n = 6; age: 20.8 ± 2.2; height: 174.7 ± 5.2; body mass: 68.0 ± 4.3; haemoglobin: 128.2 ± 11.3). The training programme applied during the study was the same for both groups, but with different environmental conditions during the selected interval training sessions. All subjects performed two high intensity interval training sessions per week in addition to two team trainings for a total of 4 weeks. During the interval training sessions the Hypoxic group trained in a normobaric hypoxic chamber at a simulated altitude of 3000 m (FI02 = 15.2), while the Control group performed similar training under normoxia conditions also inside the chamber. Players were blinded to the oxygen concentration in the chamber. Training sessions consisted of 6 sets of 30s reps with 30s rest between reps and 2 min rest between sets for a total of 60 min per training session. Approximately 1 week before and 1 week after training, explosive muscular power (counter-movement jump peak power, peak velocity and distance) aerobic performance, (Yo-Yo Intermittent Recovery Test L1) and repeated sprint ability (number of times players covered a 17 m distance in 1 min) were measured. A Student’s Paired t-test along with magnitudebased decisions was used to analyse differences between group’s pre and post training. At baseline the two
groups were similar in all characteristics apart from repeated sprint ability where the control group was able to cover significantly more ground during the test (8.5 ± 5.6 m, mean ± 95% CI) and height where the control group was significantly taller than hypoxic group (5.3 ± 3.7 cm, p =0.02). Compared to the control group, the hypoxic group
showed a likely increase in distance covered during the repeated sprint test (9.1 ± 9.0 m, p = 0.05), as a result of training, however, all other variables showed unclear differences between the groups. Adding hypoxia to high intensity training clearly improves repeated sprint ability in 3x3 female basketball players, however, the effect of hypoxia on muscular power and aerobic fitness is unclear.
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University athletes are unique because they not only have to cope with the normal psycho-physiological stress of training and playing sport, but they also need to accommodate the stress associated with their academic studies along with considerable stress from their social environment. The ability to manage and adapt to stress ultimately helps improve athletic performance, but when stress becomes too much for the athlete, it can result in maladaptation's including sleep disruption which is associated with performance loss, negative mood changes, and even injury or illness. This research aimed to determine if sleep quantity and quality were associated with maladaptation in university athletes. We examined subjective measures of sleep duration and sleep quality along with measures of mood state, energy levels, academic stress, training quality and quantity, and frequency of illness and injury in 82 young (18–23 years) elite athletes over a 1 year period in 2020. Results indicate sleep duration and quality decreased in the first few weeks of the academic year which coincided with increased training, academic and social stress. Regression analysis indicated increased levels of perceived mood (1.3, 1.1–1.5, Odds Ratio and 95% confidence limits), sleep quality (2.9, 2.5–3.3), energy levels (1.2, 1.0–1.4), training quality (1.3, 1.1–1.5), and improved academic stress (1.1, 1.0–1.3) were associated with ≥8 h sleep. Athletes that slept ≥8 h or had higher sleep quality levels were less likely to suffer injury/illness (0.8, 0.7–0.9, and 0.6, 0.5–0.7 for sleep duration and quality, respectively). In conclusion, university athletes who maintain good sleep habits (sleep duration ≥8 h/night and high sleep quality scores) are less likely to suffer problems associated with elevated stress levels. Educating athletes, coaches, and trainers of the signs and symptoms of excessive stress (including sleep deprivation) may help reduce maladaptation and improve athlete's outcomes.
Repeated-sprint training in hypoxia (RSH) studies conducted "in-season" are scarce. This study investigated the effect of discontinuous, running-based RSH, on repeated-sprint treadmill performance in hypoxia in a team sport cohort, prior to international competition. Over a 6-week "in-season" period, 11 elite male players (Malaysia national team) completed eight multi-set RSH sessions on a non-motorized treadmill in a normobaric hypoxic chamber (FiO2 = 13.8%). Three testing sessions (Sessions 1, 5, and 8), involved three sets of 5 × 8-s sprints, with 52-s recovery between sprints and 4-5 min between sets. Training sessions (Sessions 2, 3, 4, 6, and 7) consisted of four to five sets of 4-5 × 8-s sprints. During testing sessions, maximum sprinting speed was recorded for each sprint with values averaged for each set. For each set, a peak speed and fatigue index were calculated. Data were compared using two-way repeated measures ANOVA (sessions × sets). Average speed per set increased between testing sessions (p = 0.001,
η
p
2
= 0.49), with higher values in Session 8 (25.1 ± 0.9 km.h-1, +4 ± 3%, p = 0.005), but not Session 5 (24.8 ± 1.0 km.h-1, +3 ± 3%, p = 0.405), vs. Session 1 (24.2 ± 1.5 km.h-1). Peak sprinting speed in each set also increased across testing sessions (p = 0.008,
η
p
2
= 0.382), with Session 8 (26.5 ± 1.1 km.h-1) higher than Session 5 (25.8 ± 1.0 km.h-1, +1 ± 4%, p = 0.06) and Session 1 (25.7 ± 1.5 km.h-1, +4 ± 4%, p = 0.034). Fatigue index differed between sessions (p = 0.04,
η
p
2
= 0.331, Session 1; -6.8 ± 4.8%, Session 5; -3.8 ± 2%, Session 8; -5.3 ± 2.6%). In international field hockey players, a 6-week in-season RSH program improved average and peak, repeated treadmill sprint speeds following eight, but not five sessions.
This study investigated the impact of repeated-sprint (RS) training with voluntary hypoventilation at low lung volume (VHL) on RS ability (RSA) and on performance in a 30-15 intermittent fitness test (30-15IFT). Over 4 weeks, 17 basketball players included eight sessions of straight-line running RS and RS with changes of direction into their usual training, performed either with normal breathing (CTL, n = 8) or with VHL (n = 9). Before and after the training, athletes completed a RSA test (12 × 30-m, 25-s rest) and a 30-15IFT. During the RSA test, the fastest sprint (RSAbest), time-based percentage decrement score (RSASdec), total electromyographic intensity (RMS), and spectrum frequency (MPF) of the biceps femoris and gastrocnemius muscles, and biceps femoris NIRS-derived oxygenation were assessed for every sprint. A capillary blood sample was also taken after the last sprint to analyse metabolic and ionic markers. Cohen's effect sizes (ES) were used to compare group differences. Compared with CTL, VHL did not clearly modify RSAbest, but likely lowered RSASdec (VHL: −24.5% vs. CTL: −5.9%, group difference: −19.8%, ES −0.44). VHL also lowered the maximal deoxygenation induced by sprints ([HHb]max; group difference: −2.9%, ES −0.72) and enhanced the reoxygenation during recovery periods ([HHb]min; group difference: −3.6%, ES −1.00). VHL increased RMS (group difference: 18.2%, ES 1.28) and maintained MPF toward higher frequencies (group difference: 9.8 ± 5.0%, ES 1.40). These changes were concomitant with a lower potassium (K+) concentration (group difference: −17.5%, ES −0.67), and the lowering in [K+] was largely correlated with RSASdec post-training in VHL only (r = 0.66, p < 0.05). However, VHL did not clearly alter PO2, hemoglobin, lactate and bicarbonate concentration and base excess. There was no difference between group velocity gains for the 30-15IFT (CTL: 6.9% vs. VHL: 7.5%, ES 0.07). These results indicate that RS training combined with VHL may improve RSA, which could be relevant to basketball player success. This gain may be attributed to greater muscle reoxygenation, enhanced muscle recruitment strategies, and improved K+ regulation to attenuate the development of muscle fatigue, especially in type-II muscle fibers.
With minimal costs and travel constraints for athletes, the “living low-training high” (LLTH) approach is becoming an important intervention for modern sport. The popularity of the LLTH model of altitude training is also associated with the fact that it only causes a slight disturbance to athletes' usual daily routine, allowing them to maintain their regular lifestyle in their home environment. In this perspective article, we discuss the evolving boundaries of the LLTH paradigm and its practical applications for athletes. Passive modalities include intermittent hypoxic exposure at rest (IHE) and Ischemic preconditioning (IPC). Active modalities use either local [blood flow restricted (BFR) exercise] and/or systemic hypoxia [continuous low-intensity training in hypoxia (CHT), interval hypoxic training (IHT), repeated-sprint training in hypoxia (RSH), sprint interval training in hypoxia (SIH) and resistance training in hypoxia (RTH)]. A combination of hypoxic methods targeting different attributes also represents an attractive solution. In conclusion, a growing number of LLTH altitude training methods exists that include the application of systemic and local hypoxia stimuli, or a combination of both, for performance enhancement in many disciplines.
The study aimed to characterize the performance profile of 3x3 basketball and particularly to assess: a) the differences between games in live time (LT) and stoppage time (ST) phases and their ratio, and b) the game-related statistics and derived game indicators differentiating between winning and losing teams. Eight games [quarterfinals, semifinals and finals (1st and 3rd place)] of the FIBA 3x3 basketball world cup (Serbia, 17th-21st June 2017) were analysed. The LT and ST phases were categorized into three phase durations: 1-20 s, 21-40 s, >40 s. The LT/ST ratio was calculated. The game-related statistics and derived parameters were assessed through video-based notational analysis methods, and differences between winning and losing teams were calculated using a mixed linear model. The results revealed no statistically significant differences in the distribution of LT and ST phases between games, with an LT/ST ratio of 0.92±0.13. Moreover, winning teams showed a significantly higher (p
The purpose of this study was to assess the concurrent validity and test-retest reliability of a linear position transducer (LPT) for the squat jump (SJ) and counter-movement jump (CMJ) height. Twenty-eight subjects (25.18 ± 7.1 years) performed three SJs followed by three CMJs using a force plate concurrently with the LPT to test validity. Subjects returned on a separate day, at least 48 h apart, to measure test-retest reliability. A t-test showed a significant difference between the two devices for both SJ (p < 0.001) and CMJ (p < 0.001) while Bland-Altman analysis for validity revealed that the LPT overestimated jump height for both SJ (mean difference (MD) = 8.01 ± 2.93 cm) and CMJ (MD = 8.68 ± 2.99 cm). With regards to reliability of the LPT, mean intraclass correlation (ICC) for both SJ (ICC = 0.84) and CMJ (ICC = 0.95) were high, and Bland-Altman analysis showed mean differences lower than minimal detectable change (MDC) between the days for both SJ (MD = 1.89 ± 4.16 cm vs. MDC = 2.72 cm) and CMJ (MD = 0.47 ± 3.23 cm vs. MDC = 2.11 cm). Additionally, there was a low coefficient of variation (CV) between days for both SJ (CV = 3.25%) and CMJ (CV = 0.74%). Therefore, while the LPT overestimates jump height, it is a reliable tool for tracking changes in jump height to measure performance improvement and monitor fatigue.
This study examined the physiological, physical and technical responses to repeated-sprint training in normobaric hypoxia [RSH, inspired fraction of oxygen (FiO2) 14.5%] vs. normoxia (RSN, FiO2 20.9%). Within 12 days, eighteen well-trained tennis players (RSH, n = 9 vs. RSN, n = 9) completed five specific repeated-sprint sessions which consisted of four sets of 5 maximal shuttle-run sprints. Testing sessions included repeated-sprint ability and Test to Exhaustion Specific to Tennis (TEST). TEST’s maximal duration to exhaustion and time to attain the ‘onset of blood lactate accumulation’ at 4 mMol.L-1 (OBLA) improvements were significantly higher in RSH compared to RSN. Change in time to attain OBLA was concomitant with similar observation in time to the second ventilatory threshold. Significant interaction (P = 0.003) was found for ball accuracy with greater increase in RSH (+13.8 %, P = 0.013) vs. RSN (-4.6 %, P = 0.15). A correlation (r = 0.59, P < 0.001) was observed between change in ball accuracy and TEST’s time to exhaustion. Greater improvement in some tennis-specific physical and technical parameters was observed after only 5 sessions of RSH vs. RSN in well-trained tennis players.
Keywords: Sport-Specific fitness; Hypoxia; Repeated-sprint ability; V̇O2max; Ball accuracy; Tennis Performance.
Background: One of the goals of altitude training is to increase blood oxygen-carrying capacity in order to improve sea-level endurance performance in athletes. The elevated erythropoietin (EPO) production in hypoxia is a key factor in the achievement of enhanced hematological variables. The level of the EPO increase and acceleration of erythropoiesis depend on the duration of exposure and degree of hypoxia. Furthermore, many other factors may affect the hematological response to altitude training.
Aim: The purpose of this narrative review was to: (1) analyze the kinetics of EPO and hematological variables during and after altitude training; (2) summarize the current state of knowledge about the possible causes of individual or cohort differences in EPO and hematological response to altitude training; (3) formulate practical guidelines for athletes to improve the efficiency of altitude training.
Methods: A narrative review was performed following an electronic search of the databases PubMed/MEDLINE and SPORTDiscus via EBSCO for all English-language articles published between 1997 and 2017.
Results: Complete unification of results from studies on EPO kinetics was difficult due to different time and frequency of blood sampling by different researchers during and after altitude training, but the data presented in the reviewed literature allowed us to detect certain trends. The results of the reviewed studies were divergent and indicated either increase or no change of hematological variables following altitude training. Factors that may affect the hematological response to altitude training include hypoxic dose, training content, training background of athletes, and/or individual variability of EPO production.
Conclusions: Despite the potential benefits arising from altitude training, its effectiveness in improving hematological variables is still debatable. Further research and better understanding of factors influencing the response to altitude, as well as factors affecting the suitable measurement and interpretation of study results, are needed.
Background:
While adaptation to hypoxia at natural or simulated altitude has long been used with endurance athletes, it has only recently gained popularity for team-sport athletes.
Objective:
To analyse the effect of hypoxic interventions on high-intensity intermittent running performance in team-sport athletes.
Methods:
A systematic literature search of five journal databases was performed. Percent change in performance (distance covered) in the Yo-Yo intermittent recovery test (level 1 and level 2 were used without differentiation) in hypoxic (natural or simulated altitude) and control (sea level or normoxic placebo) groups was meta-analyzed with a mixed model. The modifying effects of study characteristics (type and dose of hypoxic exposure, training duration, post-altitude duration) were estimated with fixed effects, random effects allowed for repeated measurement within studies and residual real differences between studies, and the standard-error weighting factors were derived or imputed via standard deviations of change scores. Effects and their uncertainty were assessed with magnitude-based inference, with a smallest important improvement of 4% estimated via between-athlete standard deviations of performance at baseline.
Results:
Ten studies qualified for inclusion, but two were excluded owing to small sample size and risk of publication bias. Hypoxic interventions occurred over a period of 7-28 days, and the range of total hypoxic exposure (in effective altitude-hours) was 4.5-33 km h in the intermittent-hypoxia studies and 180-710 km h in the live-high studies. There were 11 control and 15 experimental study-estimates in the final meta-analysis. Training effects were moderate and very likely beneficial in the control groups at 1 week (20 ± 14%, percent estimate, ± 90% confidence limits) and 4-week post-intervention (25 ± 23%). The intermittent and live-high hypoxic groups experienced additional likely beneficial gains at 1 week (13 ± 16%; 13 ± 15%) and 4-week post-intervention (19 ± 20%; 18 ± 19%). The difference in performance between intermittent and live-high interventions was unclear, as were the dose of hypoxia and inclusion of training in hypoxia.
Conclusions:
Hypoxic intervention appears to be a worthwhile training strategy for improvement in high-intensity running performance in team-sport athletes, with enhanced performance over control groups persisting for at least 4 weeks post-intervention. Pending further research on the type of hypoxia, dose of hypoxia and training in hypoxia, coaches have considerable scope for customising hypoxic training methods to best suit their team's training schedule.
Background: Basketball is a popular, court-based team sport that has been extensively studied over the last decade.
Objective: The purpose of this article was to provide a systematic review regarding the activity demands and physiological responses experienced during basketball match-play according to playing period, playing position, playing level, geographical location, and sex.
Methods: The electronic database search of relevant articles published prior to 30 September 2016 was performed with PubMed, MEDLINE, ERIC, Google Scholar, SCIndex, and ScienceDirect. Studies that measured activity demands and/or physiological responses during basketball match-play were included.
Results: Following screening, 25 articles remained for review. During live playing time across 40-min matches, male and female basketball players travel 5-6 km at average physiological intensities above lactate threshold and 85% of maximal heart rate. Temporal comparisons show a reduction in vigorous activities in the fourth quarter, likely contributing to lower blood lactate concentrations and heart rate (HR) responses evident towards the end of matches. Guards tend to perform a higher percentage of live playing time sprinting and performing high-intensity shuffling compared with forwards and centers. Guards also perform less standing and walking during match-play compared with forwards and centers. Variations in activity demands likely account for the higher blood lactate concentrations and HR responses observed for guards compared to forwards and centers. Further, higher level players perform a greater intermittent workload than lower level players. Moreover, geographical differences may exist in the activity demands (distance and frequency) and physiological responses between Australian, African and European basketball players, whereby Australian players sustain greater workloads. While activity demands and physiological data vary across playing positions, playing levels, and geographical locations, male and female players competing at the same level experience similar demands.
Conclusion: The current results provide a detailed description of the specific requirements placed on basketball players during match-play according to playing period, playing level, playing position, geographical location, and sex, which may be useful in the development of individualized basketball training drills.
This study aims to investigate the performance changes in 19 well-trained male rugby players after repeat-sprint training (six sessions of four sets of 5 × 5 s sprints with 25 s and 5 min of active recovery between reps and sets, respectively) in either normobaric hypoxia (HYP; n = 9; FIO2 = 14.5%) or normobaric normoxia (NORM; n = 10; FIO2 = 20.9%). Three weeks after the intervention, 2 additional repeat-sprint training sessions in hypoxia (FIO2 = 14.5%) was investigated in both groups to gauge the efficacy of using “top-up” sessions for previously hypoxic-trained subjects and whether a small hypoxic dose would be beneficial for the previously normoxic-trained group. Repeated sprint (8 × 20 m) and Yo-Yo Intermittent Recovery Level 1 (YYIR1) performances were tested twice at baseline (Pre 1 and Pre 2) and weekly after (Post 1–3) the initial intervention (intervention 1) and again weekly after the second “top-up” intervention (Post 4–5). After each training set, heart rate, oxygen saturation, and rate of perceived exertion were recorded. Compared to baseline (mean of Pre 1 and Pre 2), both the hypoxic and normoxic groups similarly lowered fatigue over the 8 sprints 1 week after the intervention (Post 1: −1.8 ± 1.6%, −1.5 ± 1.4%, mean change ± 90% CI in HYP and NORM groups, respectively). However, from Post 2 onwards, only the hypoxic group maintained the performance improvement compared to baseline (Post 2: −2.1 ± 1.8%, Post 3: −2.3 ± 1.7%, Post 4: −1.9 ± 1.8%, and Post 5: −1.2 ± 1.7%). Compared to the normoxic group, the hypoxic group was likely to have substantially less fatigue at Post 3–5 (−2.0 ± 2.4%, −2.2 ± 2.4%, −1.6 ± 2.4% Post 3, Post 4, Post 5, respectively). YYIR1 performances improved throughout the recovery period in both groups (13–37% compared to baseline) with unclear differences found between groups. The addition of two sessions of “top-up” training after intervention 1, had little effect on either group. Repeat-sprint training in hypoxia for six sessions increases repeat sprint ability but not YYIR1 performance in well-trained rugby players.
The aim of the present study was to evaluate the efficacy of 3-week high intensity interval training in normobaric hypoxia (IHT) on aerobic capacity in basketball players. Twelve male well trained basketball players, randomly divided into a hypoxia (H) group (n=6; age: 22±1.6 years; VO2max: 52.6±3.9 ml/kg/min; body height - BH: 188.8±6.1 cm; body mass - BM: 83.9±7.2 kg; % of body fat - FAT%: 11.2±3.1%), and a control (C) group (n=6; age: 22±2.4 years; VO2max: 53.0±5.2 ml/kg/min; BH: 194.3 ± 6.6 cm; BM: 99.9±11.1 kg; FAT% 11.0±2.8 %) took part in the study. The training program applied during the study was the same for both groups, but with different environmental conditions during the selected interval training sessions. For 3 weeks, all subjects performed three high intensity interval training sessions per week. During the interval training sessions, the H group trained in a normobaric hypoxic chamber at a simulated altitude of 2500 m, while the group C performed interval training sessions under normoxia conditions also inside the chamber. Each interval running training sessions consisted of four to five 4 min bouts at 90% of VO2max velocity determined in hypoxia (vVO2max-hyp) for the H group and 90% of velocity at VO2max determined in normoxia for the group C. The statistical post-hoc analysis showed that the training in hypoxia caused a significant (p
Repeated sprint ability (RSA) is a critical success factor for intermittent sport performance. Repeated sprint training has been shown to improve RSA, we hypothesised that hypoxia would augment these training adaptations. Thirty male well-trained academy rugby union and rugby league players (18.4±1.5 years, 1.83±0.07 m, 88.1±8.9 kg) participated in this single-blind repeated sprint training study. Participants completed 12 sessions of repeated sprint training (10×6 s, 30 s recovery) over 4 weeks in either hypoxia (13% FiO2) or normoxia (21% FiO2). Pretraining and post-training, participants completed sports specific endurance and sprint field tests and a 10×6 s RSA test on a non-motorised treadmill while measuring speed, heart rate, capillary blood lactate, muscle and cerebral deoxygenation and respiratory measures. Yo-Yo Intermittent Recovery Level 1 test performance improved after RS training in both groups, but gains were significantly greater in the hypoxic (33±12%) than the normoxic group (14±10%, p<0.05). During the 10×6 s RS test there was a tendency for greater increases in oxygen consumption in the hypoxic group (hypoxic 6.9±9%, normoxic (−0.3±8.8%, p=0.06) and reductions in cerebral deoxygenation (% changes for both groups, p=0.09) after hypoxic than normoxic training. Twelve RS training sessions in hypoxia resulted in twofold greater improvements in capacity to perform repeated aerobic high intensity workout than an equivalent normoxic training. Performance gains are evident in the short term (4 weeks), a period similar to a preseason training block.
Over the past two decades, intermittent hypoxic training (IHT), that is, a method where athletes live at or near sea level but train under hypoxic conditions, has gained unprecedented popularity. By adding the stress of hypoxia during 'aerobic' or 'anaerobic' interval training, it is believed that IHT would potentiate greater performance improvements compared to similar training at sea level. A thorough analysis of studies including IHT, however, leads to strikingly poor benefits for sea-level performance improvement, compared to the same training method performed in normoxia. Despite the positive molecular adaptations observed after various IHT modalities, the characteristics of optimal training stimulus in hypoxia are still unclear and their functional translation in terms of whole-body performance enhancement is minimal. To overcome some of the inherent limitations of IHT (lower training stimulus due to hypoxia), recent studies have successfully investigated a new training method based on the repetition of short (<30 s) 'all-out' sprints with incomplete recoveries in hypoxia, the so-called repeated sprint training in hypoxia (RSH). The aims of the present review are therefore threefold: first, to summarise the main mechanisms for interval training and repeated sprint training in normoxia. Second, to critically analyse the results of the studies involving high-intensity exercises performed in hypoxia for sea-level performance enhancement by differentiating IHT and RSH. Third, to discuss the potential mechanisms underpinning the effectiveness of those methods, and their inherent limitations, along with the new research avenues surrounding this topic.
High-intensity interval training (HIT), in a variety of forms, is today one of the most effective means of improving cardiorespiratory and metabolic function and, in turn, the physical performance of athletes. HIT involves repeated short-to-long bouts of rather high-intensity exercise interspersed with recovery periods. For team and racquet sport players, the inclusion of sprints and all-out efforts into HIT programmes has also been shown to be an effective practice. It is believed that an optimal stimulus to elicit both maximal cardiovascular and peripheral adaptations is one where athletes spend at least several minutes per session in their 'red zone,' which generally means reaching at least 90 % of their maximal oxygen uptake ([Formula: see text]O2max). While use of HIT is not the only approach to improve physiological parameters and performance, there has been a growth in interest by the sport science community for characterizing training protocols that allow athletes to maintain long periods of time above 90 % of [Formula: see text]O2max (T@[Formula: see text]O2max). In addition to T@[Formula: see text]O2max, other physiological variables should also be considered to fully characterize the training stimulus when programming HIT, including cardiovascular work, anaerobic glycolytic energy contribution and acute neuromuscular load and musculoskeletal strain. Prescription for HIT consists of the manipulation of up to nine variables, which include the work interval intensity and duration, relief interval intensity and duration, exercise modality, number of repetitions, number of series, as well as the between-series recovery duration and intensity. The manipulation of any of these variables can affect the acute physiological responses to HIT. This article is Part I of a subsequent II-part review and will discuss the different aspects of HIT programming, from work/relief interval manipulation to the selection of exercise mode, using different examples of training cycles from different sports, with continued reference to T@[Formula: see text]O2max and cardiovascular responses. Additional programming and periodization considerations will also be discussed with respect to other variables such as anaerobic glycolytic system contribution (as inferred from blood lactate accumulation), neuromuscular load and musculoskeletal strain (Part II).
While intermittent hypoxic training (IHT) has been reported to evoke cellular responses via hypoxia inducible factors (HIFs) but without substantial performance benefits in endurance athletes, we hypothesized that repeated sprint training in hypoxia could enhance repeated sprint ability (RSA) performed in normoxia via improved glycolysis and O(2) utilization. 40 trained subjects completed 8 cycling repeated sprint sessions in hypoxia (RSH, 3000 m) or normoxia (RSN, 485 m). Before (Pre-) and after (Post-) training, muscular levels of selected mRNAs were analyzed from resting muscle biopsies and RSA tested until exhaustion (10-s sprint, work-to-rest ratio 1∶2) with muscle perfusion assessed by near-infrared spectroscopy. From Pre- to Post-, the average power output of all sprints in RSA was increased (p<0.01) to the same extent (6% vs 7%, NS) in RSH and in RSN but the number of sprints to exhaustion was increased in RSH (9.4±4.8 vs. 13.0±6.2 sprints, p<0.01) but not in RSN (9.3±4.2 vs. 8.9±3.5). mRNA concentrations of HIF-1α (+55%), carbonic anhydrase III (+35%) and monocarboxylate transporter-4 (+20%) were augmented (p<0.05) whereas mitochondrial transcription factor A (-40%), peroxisome proliferator-activated receptor gamma coactivator 1α (-23%) and monocarboxylate transporter-1 (-36%) were decreased (p<0.01) in RSH only. Besides, the changes in total hemoglobin variations (Δ[tHb]) during sprints throughout RSA test increased to a greater extent (p<0.01) in RSH. Our findings show larger improvement in repeated sprint performance in RSH than in RSN with significant molecular adaptations and larger blood perfusion variations in active muscles.
This article traces the history of scientific and empirical interval training. Scientific research has shed some light on the choice of intensity, work duration and rest periods in so-called ‘interval training’. Interval training involves repeated short to long bouts of rather high intensity exercise (equal or superior to maximal lactate steady-state velocity) interspersed with recovery periods (light exercise or rest). Interval training was first described by Reindell and Roskamm and was popularised in the 1950s by the Olympic champion, Emil Zatopek.
Since then middle- and long- distance runners have used this technique to train at velocities close to their own specific competition velocity. In fact, trainers have used specific velocities from 800 to 5000m to calibrate interval training without taking into account physiological markers. However, outside of the competition season it seems better to refer to the velocities associated with particular physiological responses in the range from maximal lactate steady state to the absolute maximal velocity. The range of velocities used in a race must be taken into consideration, since even world records are not run at a constant pace.
A study of a sample provides only an estimate of the true (population) value of an outcome statistic. A report of the study therefore usually includes an inference about the true value. Traditionally, a researcher makes an inference by declaring the value of the statistic statistically significant or nonsignificant on the basis of a P value derived from a null-hypothesis test. This approach is confusing and can be misleading, depending on the magnitude of the statistic, error of measurement, and sample size. The authors use a more intuitive and practical approach based directly on uncertainty in the true value of the statistic. First they express the uncertainty as confidence limits, which define the likely range of the true value. They then deal with the real-world relevance of this uncertainty by taking into account values of the statistic that are substantial in some positive and negative sense, such as beneficial or harmful. If the likely range overlaps substantially positive and negative values, they infer that the outcome is unclear; otherwise, they infer that the true value has the magnitude of the observed value: substantially positive, trivial, or substantially negative. They refine this crude inference by stating qualitatively the likelihood that the true value will have the observed magnitude (eg, very likely beneficial). Quantitative or qualitative probabilities that the true value has the other 2 magnitudes or more finely graded magnitudes (such as trivial, small, moderate, and large) can also be estimated to guide a decision about the utility of the outcome.
The aim of the present study was to investigate the time course of aerobic and anaerobic energy yield during supramaximal exhaustive running on the treadmill in sprint and endurance athletes. In addition, the relationships between O2 deficit, excess post-exercise O2 consumption (EPOC) and peak post-exercise blood lactate concentration (peak BLa) values were examined, Oxygen uptake during the exhaustive run and 15 min recovery period was measured using a breath-by-breath method. The accumulated O2 deficit was calculated by an extrapolation procedure. Total running time was the same for eight male sprint runners (49.5 +/- 6.0s) and for six male endurance athletes (49.4 +/- 5.3 s). The sprint group had significantly higher O2 deficit (p < 0.01) during the run as well as higher peak BLa (p < 0.05) and EPOC (p < 0.01) after the run than the endurance group. The relative contribution of anaerobic energy yield decreased from 80% to 60% during the first 15 s of the exhaustive run in both groups. The VO2 peaked and was almost unchanged from 25th to 40th s of the run in both groups, although only 79% of their VO2max was attained. The relative contribution of aerobic energy yield was significantly higher (p < 0.05) in the endurance (54-63%) than in the sprint group (43-47%) during the second half of the run. No correlation was found between the O2 deficit and EPOC but peak BLa correlated significantly (p < 0.05) with the O2 deficit (r = 0.53) and EPOC (r = 0.53). In conclusion, the energy release of the sprint and endurance athletes was different only during the second half of the exhaustive supramaximal run, when the sprinters used more the anaerobic and endurance athletes aerobic pathways for energy production.
The two Yo-Yo intermittent recovery (IR) tests evaluate an individual's ability to repeatedly perform intense exercise. The Yo-Yo IR level 1 (Yo-Yo IR1) test focuses on the capacity to carry out intermittent exercise leading to a maximal activation of the aerobic system, whereas Yo-Yo IR level 2 (Yo-Yo IR2) determines an individual's ability to recover from repeated exercise with a high contribution from the anaerobic system. Evaluations of elite athletes in various sports involving intermittent exercise showed that the higher the level of competition the better an athlete performs in the Yo-Yo IR tests. Performance in the Yo-Yo IR tests for young athletes increases with rising age. The Yo-Yo IR tests have shown to be a more sensitive measure of changes in performance than maximum oxygen uptake. The Yo-Yo IR tests provide a simple and valid way to obtain important information of an individual's capacity to perform repeated intense exercise and to examine changes in performance.
Purpose:
To determine the changes in game performance during tournament play of elite 3x3 basketball.
Methods:
361 males and 208 females competing in selected international tournaments had game demands assessed by wearable technology (GPS, inertial sensor, heart rate) along with post game blood lactate and perceived responses. Differences in the means for selected variables between games were compared using magnitude based inferences and reported with Effect Size and associated confidence limits, along with the percentage difference (ES; ±90%CL, %) of log-transformed data.
Results:
No clear differences were seen over a tournament period in PlayerLoad™ or PlayerLoad·min-1. Tournament competition elicits variable changes between games for all inertial measures. Average peak heart rate was 198 ± 10 and 198 ± 9 b∙min-1, and average game heart rate was 164 ± 12 and 165 ± 18 b∙min-1 for males and females respectively with no change between games. Average game lactate was 6.3 ± 2.4 and 6.1 ± 2.2 mmol∙L-1 for males and females respectively. Average game RPE was 5.7 ± 2.1 and 5.4 ± 2.0 AU for males and females respectively. While lactate and RPE were variable between games, there was no difference over a tournament. The physical and physiological demands of elite 3x3 games over the duration of a tournament are similar regardless of pool or championship rounds. This may imply that maintaining technical and strategic aspects leads to success rather than minimising fatigue through superior physical preparation. However, the physiological responses are high and caution is warranted in being underprepared for these demands in tournament play.
Purpose:
To determine the demands of elite male and female 3x3 basketball games, and compare these between various competition levels.
Methods:
361 males and 208 females competing in the under 18 World Championships, Senior European and World Championships, and selected professional tournaments had game demands assessed by wearable technology (GPS, inertial measurement, heart rate) along with post game blood lactate and perceived responses. Differences in the means were compared using magnitude based inferences and reported with Effect Size and 90% confidence limits, along with the percentage difference (ES; ±90%CL, %) of log-transformed data.
Results:
PlayerLoad™ and PlayerLoad™·min-1during play was 127.5 ± 31.1 and 6.7 ± 1.5, and 128.5 ± 32.0 and 6.5 ± 1.4 for males and females respectively, with small differences between junior, senior and professional levels. There were small differences in accelerations >3.5m·s between competition levels up to 0.31; ±0.20, 22.2% for males, and 0.29; ±0.19, 20.3% for females, and for decelerations >3.5m·s; 0.29; ±0.19, 19.3% for males and 0.26; ±0.19, 17.2% for females, with European championships generally greater than other levels. Average game heart rate was 165 ± 18 and 164 ± 12 bpm-1for males and females, with no difference between levels. Average RPE was 5.7 ± 2.1 and 5.4 ± 2.0 for males and females.
Conclusions:
3x3 basketball games require high speed inertial movements within limited distance creating a relatively high physiological response. Practitioners working with 3x3 players should endeavor to focus on the attributes that will improve these player characteristics for greater success.
The purposes of this study were to determine the effects of 4 wk of intensified training on resting plasma glutamine concentration, and to determine whether changes in plasma glutamine concentration relate to the appearance of upper respiratory tract infection (URTI) in swimmers during intensified training. Resting plasma glutamine concentration was measured by high performance liquid chromatography in 24 elite swimmers (8 male, 16 female, ages 15-26 yr) during 4 wk of intensified training (increased volume). Symptoms of overtraining syndrome (OT) were identified in eight swimmers (2 male, 6 female) based on decrements in swim performance and persistent high fatigue ratings; non-overtrained subjects were considered well-trained (WT). Ten of 24 swimmers (42%, 1 OT and 9 WT) exhibited URTI during the study. Plasma glutamine concentration increased significantly (P = 0.04, ANOVA) over the 4 wk, but the increase was significant only in WT swimmers(P < 0.05, post-hoc analysis). Compared with WT, plasma glutamine was significantly lower in OT at the mid-way timepoint only(P < 0.025, t-test with Bonferroni correction). There was no significant difference in glutamine levels between athletes who developed URTI and those who did not. These data suggest that plasma glutamine levels may not necessarily decrease during periods of intensified training, and that the appearance of URTI is not related to changes in plasma glutamine concentration in overtrained swimmers.
What is the topic of this review? The aim is to evaluate the effectiveness of various altitude training strategies as investigated within the last few years. What advances does it highlight? Based on the available literature, the foundation to recommend altitude training to athletes is weak. Athletes may use one of the various altitude training strategies to improve exercise performance. The scientific support for such strategies is, however, not as sound as one would perhaps imagine. The question addressed in this review is whether altitude training should be recommended to elite athletes or not. © 2016 The Authors. Experimental Physiology
To assess the impact of ‘top-up’ normoxic or hypoxic repeat-sprint training on sea-level repeat-sprint ability, thirty team sport athletes were randomly split into three groups, which were matched in running repeat-sprint ability (RSA), cycling RSA and 20 m shuttle run performance. Two groups then performed 15 maximal cycling repeat-sprint training sessions over 5 weeks, in either normoxia (NORM) or hypoxia (HYP), while a third group acted as a control (CON). In the post-training cycling RSA test, both NORM (13.6%; p = 0.0001, and 8.6%; p = 0.001) and HYP (10.3%; p = 0.007, and 4.7%; p = 0.046) significantly improved overall mean and peak power output, respectively, whereas CON did not change (1.4%; p = 0.528, and -1.1%; p = 0.571, respectively); with only NORM demonstrating a moderate effect for improved mean and peak power output compared to CON. Running RSA demonstrated no significant between group differences; however, the mean sprint times improved significantly from pre- to post-training for CON (1.1%), NORM (1.8%), and HYP (2.3%). Finally, there were no group differences in 20 m shuttle run performance. In conclusion, ‘top-up’ training improved performance in a task-specific activity (i.e. cycling); however, there was no additional benefit of conducting this ‘top-up’ training in hypoxia, since cycle RSA improved similarly in both HYP and NORM conditions. Regardless, the ‘top-up’ training had no significant impact on running RSA, therefore the use of cycle repeat-sprint training should be discouraged for team sport athletes due to limitations in specificity.
This study examined the effects of 5 weeks (∼60 min/training, 2 days/week) of run-based high-intensity, repeated-sprint ability and explosive strength / agility / sprint training in either normobaric hypoxia (RSH; FIO2 14.3%) or in normoxia (RSN; FIO2 21.0%) on physical performance in 16 highly-trained, under-18 male footballers. For both RSH (n = 8) and RSN (n = 8) groups, lower limb explosive power, sprinting (10 to 40 m) times, maximal aerobic speed, repeated-sprint (10 x 30 m, 30-s rest) and repeated-agility (6 x 20 m, 30-s rest) abilities were evaluated in normoxia before and after supervised training. Lower limb explosive power (+6.5±1.9% vs. +5.0±7.6% for RSH and RSN, respectively; both P<0.001) and performance during maximal sprinting increased (from -6.6±2.2% vs. -4.3±2.6% at 10 m to -1.7±1.7% vs. -1.3±2.3% at 40m for RSH and RSN, respectively; P values ranging from <0.05 to <0.01) to a similar extent in RSH and RSN. Both groups improved best (-3.0±1.7% vs. -2.3±1.8%; both P<0.05) and mean (-3.2±1.7%, P<0.01 vs. -1.9±2.6%, P<0.05 for RSH and RSN, respectively) repeated-sprint times, while sprint decrement did not change. Significant interactions effects (P<0.05) between condition and time were found for repeated-agility ability related-parameters with very likely greater gains (P<0.05) for RSH than RSN (initial sprint: 4.4±1.9% vs. 2.0±1.7% and cumulated times: 4.3±0.6% vs. 2.4±1.7%). Maximal aerobic speed remained unchanged throughout the protocol. In youth highly-trained football players, the addition of ten repeated-sprint training sessions performed in hypoxia vs. normoxia to their regular football practice over a 5-week in-season period was more efficient at enhancing repeated-agility ability (including direction changes), while it had no additional effect on improvements in lower limb explosive power, maximal sprinting and repeated-sprint ability performance.
Background and objective:
Hypoxic training techniques are increasingly used by athletes in an attempt to improve performance in normoxic environments. The 'live low-train high (LLTH)' model of hypoxic training may be of particular interest to athletes because LLTH protocols generally involve shorter hypoxic exposures (approximately two to five sessions per week of <3 h) than other traditional hypoxic training techniques (e.g., live high-train high or live high-train low). However, the methods employed in LLTH studies to date vary greatly with respect to exposure times, training intensities, training modalities, degrees of hypoxia and performance outcomes assessed. Whilst recent reviews provide some insight into how LLTH may be applied to enhance performance, little attention has been given to how training intensity/modality may specifically influence subsequent performance in normoxia. Therefore, this systematic review aims to evaluate the normoxic performance outcomes of the available LLTH literature, with a particular focus on training intensity and modality.
Data sources and study selection:
A systematic search was conducted to capture all LLTH studies with a matched normoxic (control) training group and the assessment of performance under normoxic conditions. Studies were excluded if no training was completed during the hypoxic exposures, or if these exposures exceeded 3 h per day. Four electronic databases were searched (PubMed, SPORTDiscus, EMBASE and Web of Science) during August 2013, and these searches were supplemented by additional manual searches until December 2013.
Results:
After the electronic and manual searches, 40 papers were deemed to meet the inclusion criteria, representing 31 separate studies. Within these 31 studies, four types of LLTH were identified: (1) continuous low-intensity training in hypoxia (CHT, n = 16), (2) interval hypoxic training (IHT, n = 4), (3) repeated sprint training in hypoxia (RSH, n = 3) and (4) resistance training in hypoxia (RTH, n = 4). Four studies also used a combination of CHT and IHT. The majority of studies reported no difference in normoxic performance between the hypoxic and normoxic training groups (n = 19), while nine reported greater improvements in the hypoxic group and three reported poorer outcomes compared with the control group. Selection of training intensity (including matching relative or absolute intensity between normoxic and hypoxic groups) was identified as a key factor in mediating the subsequent normoxic performance outcomes. Five studies included some form of normoxic training for the hypoxic group and 14 studies assessed performance outcomes not specific to the training intensity/modality completed during the training intervention.
Conclusion:
Four modes of LLTH are identified in the current literature (CHT, IHT, RSH and RTH), with training mode and intensity appearing to be key factors in mediating subsequent performance responses in normoxia. Improvements in normoxic performance appear most likely following high-intensity, short-term and intermittent training (e.g., IHT, RSH). LLTH programmes should carefully apply the principles of training and testing specificity and include some high-intensity training in normoxia. For RTH, it is unclear whether the associated adaptations are greater than those of traditional (maximal) resistance training programmes.
Statistical guidelines and expert statements are now available to assist in the analysis and reporting of studies in some biomedical disciplines. We present here a more progressive resource for sample-based studies, meta-analyses, and case studies in sports medicine and exercise science. We offer forthright advice on the following controversial or novel issues: using precision of estimation for inferences about population effects in preference to null-hypothesis testing, which is inadequate for assessing clinical or practical importance; justifying sample size via acceptable precision or confidence for clinical decisions rather than via adequate power for statistical significance; showing SD rather than SEM, to better communicate the magnitude of differences in means and nonuniformity of error; avoiding purely nonparametric analyses, which cannot provide inferences about magnitude and are unnecessary; using regression statistics in validity studies, in preference to the impractical and biased limits of agreement; making greater use of qualitative methods to enrich sample-based quantitative projects; and seeking ethics approval for public access to the depersonalized raw data of a study, to address the need for more scrutiny of research and better meta-analyses. Advice on less contentious issues includes the following: using covariates in linear models to adjust for confounders, to account for individual differences, and to identify potential mechanisms of an effect; using log transformation to deal with nonuniformity of effects and error; identifying and deleting outliers; presenting descriptive, effect, and inferential statistics in appropriate formats; and contending with bias arising from problems with sampling, assignment, blinding, measurement error, and researchers' prejudices. This article should advance the field by stimulating debate, promoting innovative approaches, and serving as a useful checklist for authors, reviewers, and editors.
There is a great demand for perceptual effort ratings in order to better understand man at work. Such ratings are important complements to behavioral and physiological measurements of physical performance and work capacity. This is true for both theoretical analysis and application in medicine, human factors, and sports. Perceptual estimates, obtained by psychophysical ratio-scaling methods, are valid when describing general perceptual variation, but category methods are more useful in several applied situations when differences between individuals are described. A presentation is made of ratio-scaling methods, category methods, especially the Borg Scale for ratings of perceived exertion, and a new method that combines the category method with ratio properties. Some of the advantages and disadvantages of the different methods are discussed in both theoretical-psychophysical and psychophysiological frames of reference.
This study examined whether training under normobaric hypoxic conditions (simulating medium level altitude) would enhance physical performance and selected muscle adaptations over and above that which occurs with normoxic training. Ten healthy males (19-25 yr) underwent 8 wk of unilateral cycle ergometry training so that one leg was trained while breathing an inspirate of 13.5% O2 and the other while breathing normal ambient air. Pre- and post-training measurements included single leg VO2max and time to fatigue at 95% VO2max. Needle biopsies from quadriceps were assayed for oxidative and glycolytic enzyme activity and analyzed for capillary density, fiber area, % fiber type, and mitochondrial and lipid volume density. VO2max, time to fatigue, citrate synthase (CS), succinate dehydrogenase, and phosphofructokinase activity increased significantly (P > 0.05) in both legs following training. The increase in CS activity in the hypoxically trained leg was also significantly greater than that in the normoxically trained leg. It thus appears that training under moderate normobaric hypoxic conditions enhances muscle citrate synthase activity to a greater extent than training under normoxic conditions.
The effect of caffeine ingestion on sprint performance is unclear. We have therefore investigated its effect on performance in a test that simulates the repeated sprints of team sports.
In a randomized double-blind crossover experiment, 16 male team-sport athletes ingested either caffeine (6 mg.kg-1 of body mass) or a placebo 60 min before performing a repeated 20-m sprint test. The test consisted of 10 sprints, each performed within 10 s and followed by rest for the remainder of each 10 s. The caffeine and placebo trials followed a familiarization trial, and the time between consecutive trials was 2-3 d. To allow estimation of variation in treatment effects between individuals, nine subjects performed three more trials without a supplement 7-14 d later. We estimated the smallest worthwhile effect on sprint time in a team sport to be approximately 0.8%.
Mean time to complete 10 sprints increased by 0.1% (95% likely range -1.5 to 1.7%) with caffeine ingestion relative to placebo. Individual variation in this effect was a standard deviation of 0.7% (-2.7 to 2.9%). Time to complete the 10th sprint was 14.4% longer than the first; caffeine increased this time by 0.7% (-1.8 to 3.2%) relative to placebo, and individual variation in this effect was 2.4% (-3.4 to 4.9%).
The observed effect of caffeine ingestion on mean sprint performance and fatigue over 10 sprints was negligible. The true effect on mean performance could be small at most, although the true effects on fatigue and on the performance of individuals could be somewhat larger. Pending confirmatory research, team-sport athletes should not expect caffeine to enhance sprint performance.
Acclimatization to moderate high altitude accompanied by training at low altitude (living high-training low) has been shown to improve sea level endurance performance in accomplished, but not elite, runners. Whether elite athletes, who may be closer to the maximal structural and functional adaptive capacity of the respiratory (i.e., oxygen transport from environment to mitochondria) system, may achieve similar performance gains is unclear. To answer this question, we studied 14 elite men and 8 elite women before and after 27 days of living at 2,500 m while performing high-intensity training at 1,250 m. The altitude sojourn began 1 wk after the USA Track and Field National Championships, when the athletes were close to their season's fitness peak. Sea level 3,000-m time trial performance was significantly improved by 1.1% (95% confidence limits 0.3-1.9%). One-third of the athletes achieved personal best times for the distance after the altitude training camp. The improvement in running performance was accompanied by a 3% improvement in maximal oxygen uptake (72.1 +/- 1.5 to 74.4 +/- 1.5 ml x kg(-1) x min(-1)). Circulating erythropoietin levels were near double initial sea level values 20 h after ascent (8.5 +/- 0.5 to 16.2 +/- 1.0 IU/ml). Soluble transferrin receptor levels were significantly elevated on the 19th day at altitude, confirming a stimulation of erythropoiesis (2.1 +/- 0.7 to 2.5 +/- 0.6 microg/ml). Hb concentration measured at sea level increased 1 g/dl over the course of the camp (13.3 +/- 0.2 to 14.3 +/- 0.2 g/dl). We conclude that 4 wk of acclimatization to moderate altitude, accompanied by high-intensity training at low altitude, improves sea level endurance performance even in elite runners. Both the mechanism and magnitude of the effect appear similar to that observed in less accomplished runners, even for athletes who may have achieved near maximal oxygen transport capacity for humans.
The purpose of this study was to assess the reliability of a repeated-sprint test, specifically designed for field-hockey, as it was based directly on the time-motion analysis of elite level competition. The test consisted of 6 x 30-m over-ground sprints departing on 25s, with an active recovery (approximately 3.1-3.3 ms(-1)) between sprints. Ten highly trained, male, field-hockey players (mean+/-S.D.: age, 23+/-3 years; body mass, 78.1+/-7.1 kg) participated in this study. Following familiarisation, the subjects performed the repeated-sprint test on two occasions, 7 days apart. The reliability of the test variables was assessed by the typical error of measurement (TE). The total sprint time was very reliable (T(1): 26.79+/-0.76 s versus T2: 26.83+/-0.74 s), as the TE was 0.7% (95% CL, 0.5-1.2%). However, the percent sprint decrement was less reliable (T1: 5.6+/-0.9% versus T2: 5.8+/-1.0%), with the TE being 14.9% (95% CL, 10.8-31.3%). In summary, it is suggested that this field-hockey-specific, repeated-sprint test is very reliable when the results are presented as the total sprint time.
The aim of this study was to determine whether 3 weeks of intermittent normobaric hypoxic exposure at rest was able to elicit changes that would benefit multi-sport athletes. Twenty-two multi-sport athletes of mixed ability were exposed to either a normobaric hypoxic gas (intermittent hypoxic training group) or a placebo gas containing normal room air (placebo group). The participants breathed the gas mixtures in 5-min intervals interspersed with 5-min recovery periods of normal room air for a total of 90 min per day, 5 days per week, over a 3-week period. The oxygen in the hypoxic gas decreased from 13% in week 1 to 10% by week 3. The training and placebo groups underwent a total of four performance tests, including a familiarization and baseline trial before the intervention, followed by trials at 2 and 17 days after the intervention. Time to complete the 3-km run decreased by 1.7%[95% confidence interval (CI) = -0.6 - 3.9%] 2 days after, and by 2.3% (CI = 0.25 - 4.4%) 17 days after, the last hypoxic episode in the training relative to the placebo group. Substantial changes in the training relative to the placebo group also included increased reticulocyte count 2 days (23.5%; CI =-1.9 to 44.9%) and 12 days (14.6%; CI = -7.1 to 36.4%) post-exposure. The effect of intermittent hypoxic training on 3-km performance found in this study is likely to be beneficial, which suggests non-elite multi-sport athletes should expect such training to enhance performance.
Multiple spr int work
- M Glaister
Glaister M. Multiple spr int work. Spor ts Med.
2005;35(9):757-77.