Sweat Characteristics and Fluid Balance Responses During Two Heat Training Camps in Elite Female Field Hockey Players.

We examined the sweat characteristics and fluid balance of elite female field hockey players during two heat training camps. Fourteen elite female field hockey players from the Australian national squad participated in two heat training camps held ∼6 months apart, following winter- (Camp 1) and summer-based training (Camp 2). Daily waking body mass (BM) and urine specific gravity (USG) were collected, along with several markers of sweat and fluid balance across two matches per camp. There was a 19% mean reduction in estimated whole-body sweat sodium concentration from Camp 1 (45.8 ± 6.5 mmol/L) to Camp 2 (37.0 ± 5.0 mmol/L; p < .001). Waking urine specific gravity ≥ 1.020 was observed in 31% of samples, with no significant differences in mean urine specific gravity or BM between camps (p > .05), but with substantial interindividual variation. Intramatch sweat rates were high (1.2-1.8 L/hr), with greater BM losses in Camp 1 (p = .030), resulting in fewer players losing ≥2% BM in Camp 2 (0%-8%), as compared with Camp 1 (36%-43%; p = .017). Our field data suggest that elite female field hockey players experience substantial sweat losses during competition in the heat regardless of the season. In agreement with previous findings, we observed substantial interindividual variation in sweat and hydration indices, supporting the use of individualized athlete hydration strategies.

Shifting the Energy Toward Los Angeles: Comparing the Energetic Contribution and Pacing Approach Between 2000- and 1500-m Maximal Ergometer Rowing.

PURPOSE: To compare the energetic contribution and pacing in 2000- and 1500-m maximal rowing-ergometer performances. METHODS: On separate visits (>48 h apart, random order), 18 trained junior (16.7 [0.4] y) male rowers completed 3 trials: a 7 × 4-minute graded exercise test, a 2000-m time trial (TT2000), and a 1500-m TT (TT1500). Respiratory gases were continuously measured throughout each trial. The submaximal power-to-oxygen-consumption relationship from the graded exercise test was used to determine the accumulated oxygen deficit for each TT. Differences in mean power output (MPO), relative anaerobic contribution, percentage of peak oxygen uptake, pacing index, maximum heart rate, rating of perceived exertion, and blood lactate concentration were assessed using linear mixed modeling. RESULTS: Compared to TT2000 (324 [24] W), MPO was 5.2% (3.3%) higher in TT1500 (341 [29 W]; P < .001, ηp2=.70). There was a 4.9% (3.3%) increase (P < .001, ηp2=.71) in anaerobic contribution from 17.3% (3.3%) (TT2000) to 22.2% (4.3%) (TT1500). Compared to TT1500, maximum heart rate, rating of perceived exertion, and blood lactate concentration were all greater (P < .05) in TT2000. The pacing index was not different between trials. Percentage increase in MPO from TT2000 to TT1500 was negatively associated with pacing variance in TT1500 (R2 = .269, P = .027). CONCLUSIONS: Maximal ergometer performance over 1500 m requires a significantly greater anaerobic contribution compared with 2000 m. Junior male athletes adopt a consistent pacing strategy across both distances. However, those who experienced greater percentage increases in MPO over the shorter test adopted a more even pacing strategy. To prepare for 1500-m performance, greater emphasis should be placed on developing capacity for work in the severe domain and completing race simulations with a more even pacing strategy.

An Updated Panorama of Blood-Flow-Restriction Methods.

BACKGROUND: Exercise with blood-flow restriction (BFR) is being increasingly used by practitioners working with athletic and clinical populations alike. Most early research combined BFR with low-load resistance training and consistently reported increased muscle size and strength without requiring the heavier loads that are traditionally used for unrestricted resistance training. However, this field has evolved with several different active and passive BFR methods emerging in recent research. PURPOSE: This commentary aims to synthesize the evolving BFR methods for cohorts ranging from healthy athletes to clinical or load-compromised populations. In addition, real-world considerations for practitioners are highlighted, along with areas requiring further research. CONCLUSIONS: The BFR literature now incorporates several active and passive methods, reflecting a growing implementation of BFR in sport and allied health fields. In addition to low-load resistance training, BFR is being combined with high-load resistance exercise, aerobic and anaerobic energy systems training of varying intensities, and sport-specific activities. BFR is also being applied passively in the absence of physical activity during periods of muscle disuse or rehabilitation or prior to exercise as a preconditioning or performance-enhancement technique. These various methods have been reported to improve muscular development; cardiorespiratory fitness; functional capacities; tendon, bone, and vascular adaptations; and physical and sport-specific performance and to reduce pain sensations. However, in emerging BFR fields, many unanswered questions remain to refine best practice.

Demarcation of Intensity From 3 to 5 Zones Aids in Understanding Physiological Performance Progression in Highly Trained Under-23 Rowing Athletes.

ABSTRACT: Watts, SP, Binnie, MJ, Goods, PSR, Hewlett, J, Fahey-Gilmour, J, and Peeling, P. Demarcation of intensity from 3 to 5 zones aids in understanding physiological performance progression in highly trained under-23 rowing athletes. J Strength Cond Res 37(11): e593-e600, 2023-The purpose of this investigation was to compare 2 training intensity distribution models (3 and 5 zone) in 15 highly trained rowing athletes ( n = 8 male; n = 7 female; 19.4 ± 1.1 years) to determine the impact on primary (2,000-m single-scull race) and secondary (2,000-m ergometer time trial, peak oxygen consumption [V̇O 2 peak], lactate threshold 2 [LT2 power]) performance variables. Performance was assessed before and after 4 months training, which was monitored through a smart watch (Garmin Ltd, Olathe, KS) and chest-strap heart rate (HR) monitor (Wahoo Fitness, Atlanta, GA). Two training intensity distribution models were quantified and compared: a 3-zone model (Z1: between 50% V̇O 2 peak and lactate threshold 1 (LT1); Z2: between LT1 and 95% LT2; Z3: >95% LT2) and a 5-zone model (T1-T5), where Z1 and Z3 were split into 2 additional zones. There was significant improvement in LT2 power for both male (4.08% ± 1.83, p < 0.01) and female (3.52% ± 3.38, p = 0.02) athletes, with male athletes also demonstrating significant improvement in 2,000-m ergometer time trial (2.3% ± 1.92, p = 0.01). Changes in V̇O 2 peak significantly correlated with high-quality aerobic training (percent time in T2 zone; r = 0.602, p = 0.02), whereas changes in LT2 power significantly correlated with "threshold" training (percent time in T4 zone; r = 0.529, p = 0.04). These correlations were not evident when examining intensity distribution through the 3-zone model. Accordingly, a 5-zone intensity model may aid in understanding the progression of secondary performance metrics in rowing athletes; however, primary (on-water) performance remains complex to quantify.

Quantifying on-water performance in rowing: A perspective on current challenges and future directions.

Winning times at benchmark international rowing competitions (Olympic Games and World Championships) are known to vary greatly between venues, based on environmental conditions and the strength of the field. Further variability in boat speed for any given effort is found in the training environment, with less controlled conditions (i.e., water flow, non-buoyed courses), fewer world class competitors, and the implementation of non-race specific effort distances and intensities. This combination of external factors makes it difficult for coaches and practitioners to contextualise the performance underpinning boat speed or race results on any given day. Currently, a variety of approaches are referenced in the literature and used in practice to quantify this underpinning performance time or boat speed, however, no clear consensus exists. The use of relative performance (i.e., time compared to other competitors), accounting for influence of the weather (i.e., wind and water temperature), and the novel application of instrumented boats (with power instrumentation) have been suggested as potential methods to improve our understanding of on-water rowing speeds. Accordingly, this perspective article will discuss some of these approaches from recent literature, whilst also sharing experience from current practice in the elite environment, to further stimulate discussion and help guide future research.

Concurrent validity of the CORE wearable sensor with BodyCap temperature pill to assess core body temperature during an elite women's field hockey heat training camp.

Wearable temperature sensors offer the potential to overcome several limitations associated with current laboratory- and field-based methods for core temperature assessment; however, their ability to provide accurate data at elevated core temperatures (Tc) has been questioned. Therefore, this investigation aimed to determine the concurrent validity of a wearable temperature sensor (CORE) compared to a reference telemetric temperature pill (BodyCAP) during a team-sport heat training camp prior to the 2020 Olympic Games. Female field hockey players (n = 19) in the Australian national squad completed 4 sessions in hot conditions where their temperature was monitored via CORE and BodyCAP. Concurrent validity of the wearable CORE device was determined with reference to the ingested BodyCAP pill. Lin's Concordance Correlation Coefficients determined there was "poor" agreement between devices during all sessions. Mean bias demonstrated that CORE underestimated Tc in all sessions (-0.06°C to -0.34°C), with wide mean 95% confidence intervals (±0.35°C to ±0.56°C). Locally estimated scatterplot smoothing regression lines illustrated a non-linearity of error, with greater underestimation of Tc by the CORE device, as Tc increased. The two devices disagreed more than ±0.3°C for 41-60% of all data samples in each session. Our findings do not support the use of the CORE device as a valid alternative to telemetric temperature pills for Tc assessment, particularly during exercise in hot conditions where elevated Tc are expected.

The CORE wearable sensor is not a valid alternative to telemetric temperature pills for Tc assessment, particularly during exercise in hot conditions where elevated Tc are expected.Compared to reference Tc data provided by a validated, ingestible telemetric temperature pill, the CORE device demonstrated "poor" agreement between devices during all sessions in this investigation.There was a non-linear bias which tended to underestimate Tc to a greater extent as Tc increased (but with wide confidence intervals), with 41-60% of all data exceeding a threshold error of ±0.3°C.

Sprint cycling rate of torque development associates with strength measurement in trained cyclists.

PURPOSE: A cyclist's rate of force/torque development (RFD/RTD) and peak force/torque can be measured during single-joint or whole-body isometric tests, or during cycling. However, there is limited understanding of the relationship between these measures, and of the mechanisms that contribute to each measure. Therefore, we examined the: (i) relationship between quadriceps central and peripheral neuromuscular function with RFD/RTD in isometric knee extension, isometric mid-thigh pull (IMTP), and sprint cycling; and (ii) relationship among RFD/RTD and peak force/torque between protocols. METHODS: Eighteen trained cyclists completed two familiarisation and two experimental sessions. Each session involved an isometric knee extension, IMTP, and sprint cycling protocol, where peak force/torque, average and peak RFD/RTD, and early (0-100 ms) and late (0-200 ms) RFD/RTD were measured. Additionally, measures of quadriceps central and peripheral neuromuscular function were assessed during the knee extension. RESULTS: Strong relationships were observed between quadriceps early EMG activity (EMG50/M) and knee extension RTD (r or ρ = 0.51-0.65) and IMTP late RFD (r = 0.51), and between cycling early or late RTD and peak twitch torque (r or ρ = 0.70-0.75). Strong-to-very strong relationships were observed between knee extension, IMTP, and sprint cycling for peak force/torque, early and late RFD/RTD, and peak RFD/RTD (r or ρ = 0.59-0.80). CONCLUSION: In trained cyclists, knee extension RTD or IMTP late RFD are related to measures of quadriceps central neuromuscular function, while cycling RTD is related to measures of quadriceps peripheral neuromuscular function. Further, the strong associations among force/torque measures between tasks indicate a level of transferability across tasks.

Repeated-sprint training in heat and hypoxia: Acute responses to manipulating exercise-to-rest ratio.

The aim of this study was to investigate acute performance and physiological responses to the manipulation of exercise-to-rest ratio (E:R) during repeated-sprint hypoxic training (RSH) in hot conditions. Twelve male team-sport players completed two experimental sessions at a simulated altitude of ∼3000 m (FIO2 0.144), air temperature of 40°C and relative humidity of 50%. Exercise involved either 3 × 5 × 10-s (E:R1:2) or 3 × 10 × 5-s (E:R1:4) maximal cycling sprints interspersed with active recoveries at 120W (20-s between sprints, 2.5 and 5-min between sets for E:R1:2 and E:R1:4 respectively). Sessions were matched for overall sprint and total session duration (47.5-min). Peak and mean power output, and total work were greater in E:R1:4 than E:R1:2 (p < 0.05). Peak core temperature was significantly higher in E:R1:4 than E:R1:2 (38.44 ± 0.33 vs. 38.20 ± 0.35°C, p = 0.028). Muscle deoxygenation magnitude during sprints was greater in E:R1:2 (28.2 ± 1.6 vs. 22.4 ± 4.6%, p < 0.001), while muscle reoxygenation did not differ between conditions (p > 0.05). These results indicate E:R1:4 increased mechanical power output and core temperature compared to E:R1:2. Both protocols had different effects on measures of muscle oxygenation, with E:R1:2 generating greater muscle oxygen extraction and E:R1:4 producing more muscle oxygenation flux, which are both important signals for peripheral adaptation. We conclude that the E:R manipulation during RSH in the heat might be used to target different physiological and performance outcomes, with these findings forming a strong base for future mechanistic investigation.Highlights During a typical repeated-sprint training session conducted in hot and hypoxic conditions, an exercise-to-rest ratio of 1:4 during sprint efforts displayed an increased mechanical power output compared to an exercise-to-rest ratio of 1:2. This represents a potentially useful increase in training stimulus.An exercise-to-rest ratio of 1:2 generated greater muscle oxygen extraction, while an exercise-to-rest ratio of 1:4 resulted in more muscle oxygenation flux and a higher core temperature, indicating key markers of environment-related physiological strain were varied between conditions.Exercise-to-rest ratio manipulation may be used to target different physiological and performance outcomes when prescribing repeated-sprint training in hot and hypoxic conditions.

Assessing the rate of torque development in sprint cycling: a methodological study.

The present study examined (i) the magnitude of the rate of torque development (RTD) and (ii) the between-day reliability of RTD at the start of a cycling sprint when sprint resistance, sprint duration, and the pedal downstroke were altered. Nineteen well-trained cyclists completed one familiarisation and three testing sessions. Each session involved one set of 1-s sprints and one set of 5-s sprints. Each set contained one moderate (0.3 N m kg-1), one heavy (0.6 N m kg-1), and one very heavy (1.0 N m kg-1) resistance sprint. RTD measures (average and peak RTD, RTD 0-100 ms, and RTD 0-200 ms) were calculated for downstroke 1 in the 1-s sprint. For the 5-s sprints, RTD measures were calculated for each of the first three downstrokes, as an average of downstrokes 1 and 2, and as an average of downstrokes 2 and 3. Whilst RTDs were greatest in downstroke 3 at all resistances, the greatest number of reliable RTD measures were obtained using the average of downstrokes 2 and 3 with heavy or very heavy resistances, where average and peak RTD, and RTD 0-200 ms were deemed reliable (ICC ≥ 0.8, CV ≤ 10%). Since only 1-2 downstrokes can be completed within 1 s, the greatest RTD reliability cannot be achieved using a 1-s sprint; therefore, the average of downstrokes 2 and 3 during a >2-s cycling sprint (e.g. 5-s test) with heavy or very heavy resistance is recommended for the assessment of RTD in sprint cyclists.HighlightsWhilst RTD measures were greatest in pedal downstroke 3 at all resistances, the greatest number of reliable RTD measures were obtained using the average of pedal downstrokes 2 and 3 with heavy or very heavy resistances, with average and peak RTD, and RTD 0-200 ms having acceptable reliability.RTD 0-100 ms and all RTD measurements for downstroke 1 were not reliable and should not be used. As only 1-2 downstrokes can be performed in 1 s, the greatest RTD reliability cannot be achieved using a 1-s sprint. Instead, RTD may be evaluated using a 5-s sprint.

Increased air temperature during repeated-sprint training in hypoxia amplifies changes in muscle oxygenation without decreasing cycling performance.

The present study aims to investigate the acute performance and physiological responses, with specific reference to muscle oxygenation, to ambient air temperature manipulation during repeated-sprint training in hypoxia (RSH). Thirteen male team-sport players completed one familiarisation and three experimental sessions at a simulated altitude of ∼3000 m (FIO2 0.144). Air temperatures utilised across the three experimental sessions were: 20°C, 35°C and 40°C (all 50% relative humidity). Participants performed 3 × 5 × 10-s maximal cycle sprints, with 20-s passive recovery between sprints, and 5 min active recovery between sets. There were no differences between conditions for cycling peak power, mean power, and total work (p>0.05). Peak core temperature (Tc) was not different between conditions (38.11 ± 0.36°C). Vastus lateralis muscle deoxygenation during exercise and reoxygenation during recovery was of greater magnitude in 35°C and 40°C than 20°C (p<0.001 for all). There was no condition × time interaction for Tc, skin temperature, pulse oxygen saturation, heart rate, rating of perceived exertion and thermal sensation (P>0.05). Exercise-induced increases in blood lactate concentration were higher in 35°C and 40°C than 20°C (p=0.010 and p=0.001, respectively). Integrating ambient temperatures up to 40°C into a typical RSH session had no detrimental effect on performance. Additionally, the augmented muscle oxygenation changes experienced during exercise and recovery in temperatures ≥35°C may indicate that the potency of RSH training is increased with additional heat. However, alterations to the training session may be required to generate a sufficient rise in Tc for heat training purposes.Highlights Heat exposure (35-40°C) did not affect mechanical performance during a typical RSH session. This indicates hot ambient temperature can be implemented during RSH, without negative consequence to training output.Hotter ambient conditions (35-40°C) likely result in greater muscle oxygenation changes during both exercise and recovery compared to temperate conditions.Although hotter sessions were perceived as more difficult and more thermally challenging, they did not further elevate Tc beyond that of temperate conditions. Accordingly, if intended to be used for heat acclimation purposes, alterations to the session may be required to increase heat load.

Rowing in Los Angeles: Performance Considerations for the Change to 1500 m at the 2028 Olympic Games.

BACKGROUND: World Rowing's decision to support the proposed change from a 2000-m to a 1500-m regatta course at the 2028 Olympic Games in Los Angeles is anticipated to have important implications for athlete preparation and race execution during the 2024-2028 quadrennium. PURPOSE: This commentary aims to provide insight into the expected implications of the reduction in course length heading into the 2028 Games, focusing on the training and monitoring of high-performance rowers, as well as tactical, technical, and pacing considerations for performance. The reduction in event duration (estimated to be ∼90-120 s across all event classes) will lead to an expected ∼5% to 15% increase in relative contribution of anaerobic metabolism. Consequently, adjustment in training periodization priorities toward higher-intensity interventions may be required, especially in the period immediately prior to the games. The critical-power and anaerobic-power-reserve concepts may become more useful tools for structuring exercise programs, evaluating training outcomes, and determining event suitability through individual physiological profiling. Additionally, the adoption of a more constant (flat) pacing strategy, rather than the commonly used reverse J-shaped approach, might be considered for racing over this new distance. Finally, technical aspects, such as stroke rate and gearing, may require adjustment for optimal performance; however, research is clearly required to explore such effects. CONCLUSIONS: Our intention is to stimulate discussion and debate, with the provision of practical recommendations that aim to optimize rowers' preparation for and performance at the 2028 Olympic Games.

Taking the plunge: When is best for hot water immersion to complement exercise in heat and hypoxia.

This investigation assessed the psycho-physiological and performance effects of hot water immersion (HWI) implemented either before or after a repeated-sprint training in hypoxia (RSH) session conducted in the heat. Ten participants completed three RSH trials (3 × 10 × 5-s sprints), conducted at 40°C and simulated altitude of 3000 m. A 30-min monitoring period preceded and followed all exercise sessions. In PRE, the pre-exercise period was HWI, and the post-exercise period was seated rest in temperate conditions. This combination was reversed in POST. In CON, participants were seated in temperate conditions for both periods. Compared to CON, PRE elicited a reduction in power output during each repeated-sprint set (14.8-16.2%, all p < 0.001), and a significantly higher core temperature (Tc) during the pre-exercise period and throughout the exercise session (p < 0.001 and p = 0.025, respectively). In POST, power output and Tc until the end of exercise were similar to CON, with Tc higher at the conclusion of the post-exercise period (p < 0.001). Time across the entire protocol spent ≥38.5°C Tc was significantly longer in PRE (48.1 ± 22.5 min) than POST (31.0 ± 11.3 min, p = 0.05) and CON (15.8 ± 16.3 min, p < 0.001). Employing HWI following RSH conducted in the heat provides effective outcomes regarding physiological strain and cycling performance when compared to pre-exercise or no HWI.

A repeated shuttle sprint test with female and male international field hockey players is reliable and associated with single sprint but not intermittent endurance performance.

Field hockey is a high-intensity intermittent team sport that has recently undergone a series of rule changes that have resulted in a greater demand for repeated high-intensity movements. Coaches and practitioners now require a reliable assessment of repeated accelerations, decelerations and changes of direction to assess these important match qualities. This investigation assessed the test-retest reliability of a novel 6x40m repeated shuttle sprint test (20m + 20m with a 180° turn) and its association with 40m straight line sprint and YoYo Intermittent Recovery Test performance in 28 International field hockey players (n = 14 females and n = 14 males). The sum of 6 sprint times (SUM) demonstrated 'excellent' (ICC = 0.94 and CV = 0.59%) and 'good' (ICC = 0.84 and CV = 0.75%) reliability in females and males, respectively. Best sprint time during the repeated shuttle sprint test also demonstrated suitable reliability to evaluate field hockey physical performance (ICC = 0.92 & 0.76, CV = 0.76% & 1.00% in females and males, respectively). SUM was significantly associated with 40 m straight line sprint performance in females (r = 0.90; p<0.001) and males (r = 0.92; p<0.001), but only a weak association was found with YoYo Intermittent Recovery Test performance for either group (r = 0.20; p = 0.495 & r = -0.19; p = 0.525 in females and males, respectively). In summary, field hockey testing batteries that include a repeated shuttle sprint test should consider including a test of intermittent endurance. Further, changes in SUM greater than 1.0% can be confidently interpreted by coaches and practitioners as a real change for both female and male elite field hockey players.

Validity and Reliability of a Field Hockey-Specific Dribbling Speed Test.

ABSTRACT: Tapsell, LC, Binnie, MJ, Lay, BS, Dawson, BT, and Goods, PSR. Validity and reliability of a field hockey-specific dribbling speed test. J Strength Cond Res 36(6): 1720-1725, 2022-The present study aimed to design a valid and reliable test for field hockey players that concurrently assesses the skill of dribbling and sport-specific agility. In total, 27 male and 32 female subjects were recruited from amateur (n = 20), state-level (n = 22), and national-level (n = 17) field hockey teams. The test course was developed in consultation with state- and national-level field hockey coaches, and using match analyses from existing literature. Subjects were familiarized before completing a testing session that consisted of 3 maximal-effort trials through a field hockey-specific course while dribbling a hockey ball, and another 3 trials of the same course without dribbling the ball. Amateur and state subjects completed an additional session for test-retest reliability analysis. Electronic timing gates recorded time to complete the course with the ball (DRIBBLE), without the ball (SPRINT), and the difference between DRIBBLE and SPRINT (DELTA). With significance set at p < 0.05, subjects of higher playing levels recorded significantly faster DRIBBLE (p < 0.001) and significantly lower DELTA (p < 0.001) times. No significant difference was found between player levels for SPRINT (p = 0.484) times. Intraclass correlations were 0.84 and 0.81 for DELTA and DRIBBLE, respectively. In conclusion, the dribbling test trialed here has sufficient validity and reliability for use in performance testing of field hockey athletes and can be implemented across playing levels to objectively track skill progression.

Heat Added to Repeated-Sprint Training in Hypoxia Does Not Affect Cycling Performance.

PURPOSE: This study aimed to assess the influence of graded air temperatures during repeated-sprint training in hypoxia (RSH) on performance and physiological responses. METHODS: Ten well-trained athletes completed one familiarization and 4 experimental sessions at a simulated altitude of 3000 m (0.144 FIO2) above sea level. Air temperatures utilized across the 4 experimental sessions were 20°C, 25°C, 30°C, and 35°C (all 50% relative humidity). The participants performed 3 sets of 5 × 10 seconds "all-out" cycle sprints, with 20 seconds of active recovery between sprints and 5 minutes of active recovery between sets (recovery intensity = 120 W). Core temperature, skin temperature, pulse oxygen saturation, heart rate, rating of perceived exertion, and thermal sensation were collected. RESULTS: There were no differences between conditions for peak power, mean power, and total work in each set (P > .05). There were no condition × time interaction effects for any variables tested. The peak core temperature was highest at 30°C (38.06°C [0.31°C]). Overall, the pulse oxygen saturation was higher at 35°C than at 20°C (P < .001; d < 0.8), 25°C (P < .001; d = 1.12 ± 0.54, large), and 30°C (P < .001; d = 0.84 ± 0.53, large). CONCLUSION: Manipulating air temperature between 20°C and 35°C had no effect on performance or core temperature during a typical RSH session. However, the pulse oxygen saturation was preserved at 35°C, which may not be a desirable outcome for RSH interventions. The application of increased levels of ambient heat may require a different approach if augmenting the RSH stimulus is the desired outcome.

An Updated Panorama of "Living Low-Training High" Altitude/Hypoxic Methods.

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.

Body composition assessment in athletes: Comparison of a novel ultrasound technique to traditional skinfold measures and criterion DXA measure.

OBJECTIVES: This investigation compared ultrasound and skinfolds as measures of body fat for athletes, relative to dual-energy X-ray absorptiometry. DESIGN: Fifty-six well-trained athletes from various sports participated in a cross-sectional study. METHODS: The participants attended one testing session, where total body fat mass was measured using dual-energy X-ray absorptiometry, and subcutaneous adipose tissue was measured using brightness-mode ultrasound and skinfolds with callipers. The ultrasound and skinfold measures were correlated independently against standardised fat mass from dual-energy X-ray absorptiometry. RESULTS: The correlation between standardised fat mass and sum-of-eight (Σ8) sites ultrasound (r=0.959, p<0.001), and with sum-of-seven (Σ7) sites skinfolds (r=0.911, p<0.001), were both high positive correlations. In the lowest quartile by fat proportion, the correlation between standardised fat mass and Σ8 ultrasound (r=0.811, p<0.001) was a high positive correlation, whilst the correlation with Σ7 skinfolds (r=0.652, p=0.011) was a moderate positive correlation. In the highest quartile by fat proportion, the correlation between standardised fat mass and Σ8 ultrasound (r=0.847, p<0.001) was a high positive correlation, whilst the correlation with Σ7 skinfolds (r=0.591, p=0.026) was a moderate positive correlation. CONCLUSIONS: Ultrasound and skinfolds are both very good methods to accurately assess body composition in athletes, relative to dual-energy X-ray absorptiometry. However, ultrasound delivered consistently more accurate results, throughout a broad athletic spectrum.

Topical Sodium Bicarbonate: No Improvement in Blood Buffering Capacity or Exercise Performance.

PURPOSE: To assess the efficacy of a topical sodium bicarbonate (0.3 g/kg body weight NaHCO3) application (PR lotion; Amp Human) on blood buffering capacity and performance in recreationally active participants (study A) and moderately trained athletes (study B). METHODS: In Study A, 10 participants completed 2 experimental trials: oral NaHCO3 (0.3 g/kg body weight + placebo lotion) or PR lotion (0.9036 g/kg body weight + oral placebo) applied 90 minutes prior to a cycling task to exhaustion (30-s sprints at 120% peak power output with 30-s rest). Capillary blood was collected and analyzed for pH, bicarbonate, and lactate every 10 minutes throughout the 90-minute loading period and postexercise at 5, 10, and 15 minutes. In Study B, 10 cyclists/triathletes completed 2 experimental trials, applying either PR or placebo lotion 30 minutes prior to a cycling performance task (3 × 30-s maximal sprints with 90-s recovery). Capillary blood samples were collected at baseline, preexercise, and postexercise and analyzed as per study A. RESULTS: In Study A, pH and bicarbonate were significantly elevated from baseline after 10 minutes in the oral NaHCO3 condition and throughout recovery compared with no elevation in the PR lotion condition (P < .001). No differences in cycling time occurred between PR lotion (349 [119] s) and oral NaHCO3 (363 [80] s; P = .697). In Study B, no differences in blood parameters, mean power (P = .108), or peak power (P = .448) were observed between conditions. CONCLUSIONS: PR lotion was ineffective in altering blood buffering capacity or enhancing performance in either trained or untrained individuals.