Concurrent Heat and Intermittent Hypoxic Training: No Additional Performance Benefit Over Temperate Training.

PURPOSE: To examine whether concurrent heat and intermittent hypoxic training can improve endurance performance and physiological responses relative to independent heat or temperate interval training. METHODS: Well-trained male cyclists (N = 29) completed 3 weeks of moderate- to high-intensity interval training (4 × 60 min·wk-1) in 1 of 3 conditions: (1) heat (HOT: 32°C, 50% relative humidity, 20.8% fraction of inspired oxygen, (2) heat + hypoxia (H+H: 32°C, 50% relative humidity, 16.2% fraction of inspired oxygen), or (3) temperate environment (CONT: 22°C, 50% relative humidity, 20.8% fraction of inspired oxygen). Performance 20-km time trials (TTs) were conducted in both temperate (TTtemperate) and assigned condition (TTenvironment) before (base), immediately after (mid), and after a 3-week taper (end). Measures of hemoglobin mass, plasma volume, and blood volume were also assessed. RESULTS: There was improved 20-km TT performance to a similar extent across all groups in both TTtemperate (mean ±90% confidence interval HOT, -2.8% ±1.8%; H+H, -2.0% ±1.5%; CONT, -2.0% ±1.8%) and TTenvironment (HOT, -3.3% ±1.7%; H+H, -3.1% ±1.6%; CONT, -3.2% ±1.1%). Plasma volume (HOT, 3.8% ±4.7%; H+H, 3.3% ±4.7%) and blood volume (HOT, 3.0% ±4.1%; H+H, 4.6% ±3.9%) were both increased at mid in HOT and H+H over CONT. Increased hemoglobin mass was observed in H+H only (3.0% ±1.8%). CONCLUSION: Three weeks of interval training in heat, concurrent heat and hypoxia, or temperate environments improve 20-km TT performance to the same extent. Despite indications of physiological adaptations, the addition of independent heat or concurrent heat and hypoxia provided no greater performance benefits in a temperate environment than temperate training alone.

Positional Demands and Physical Activity Profiles of Netball.

van Gogh, MJ, Wallace, LK, and Coutts, AJ. Positional demands and physical activity profiles of netball. J Strength Cond Res 34(5): 1422-1430, 2020-The aim of this study was to examine the activity profiles and physiological demands of netball. Eleven representative youth netball players participated in this study. Global positioning system, heart rate, and accelerometer data were collected during 8 competitive matches. Sport-specific skills were analyzed using notational methods. The main findings were that players traveled less distance during a match than previously reported. The center covered significantly greater distances than the other positions (p < 0.001). The goal shooter and goal keeper covered the least distance and endured lower accelerometer loads than other positions (p < 0.001). Very low levels of very high-speed running and sprint efforts were observed across all positions. The proportion of time spent in the high (>85% maximum heart rate [HRmax]) HR zone ranged from 7.0 to 62.6%, highlighting a high variation in cardiovascular demands between each position. The center and goal attack had the greatest cardiovascular demands spending significantly more time in the high (>85% HRmax) HR zone (p < 0.001). The goal shooter and goal keeper spent significantly more time in the low (<70% HRmax) HR zone (p < 0.001). Players in attacking positions were shown to pass/catch significantly more players than in defending positions (p < 0.001). Players in defending positions had higher number of deflections and intercepts compared with players in attacking positions (p < 0.001). These findings reveal significant positional differences in activity profiles and movement demands in netball. These data can be used to refine position-specific training practice and guide tactical strategies during competition.

Establishing the criterion validity and reliability of common methods for quantifying training load.

The purpose of this investigation was to compare the criterion validity and test-retest reliability of common methods for quantifying training load. Ten (5 men and 5 women) recreational athletes (mean ± SD, VO2max: 37.0 ± 4.3 ml·kg-1·min-1; age: 23.8 ± 8.4 years) completed 18 randomly assigned steady state (SS) and interval (INT) training sessions during a 6-week period. Steady-state sessions were 18 minutes in duration and were performed at 35, 50, and 65% of maximum work capacity (Wmax). Interval sessions were performed at 50, 60, and 70% of Wmax with a work to rest ratio of 1:1 and matched for total work with the 50% SS session. Oxygen consumption (VO2) and heart rate (HR) were measured throughout all sessions, whereas blood lactate concentration and rating of perceived exertion (RPE) measures were taken every 6 minutes during sessions. Session-RPE (sRPE) was collected after each exercise bout. All individual correlations between VO2 and external work (r = 0.88-0.97), HR (r = 0.65-0.90), and RPE-based methods (r = 0.55-0.89) were statistically significant. External work correlated best with the total V[Combining Dot Above]O2 and was significantly different from RPE-based methods. A poor level of test-retest reliability was shown for Banister's TRIMP (15.6% coefficient of variation [CV]), Lucia's TRIMP (10.7% CV), and sRPE (28.1% CV). Good reliability was shown for HR (3.9% CV) and a moderate level for RPE 6-20 (8.5% CV) as a measure of exercise intensity. These results suggest external work to be the most valid and reliable method for quantifying training load. Poor levels of reliability were reported for each of the HR-based TRIMP methods and RPE-based methods.

The ecological validity and application of the session-RPE method for quantifying training loads in swimming.

There are few practical methods available for evaluating training loads (TL) during swimming. The purpose of this study was to examine the ecological validity of the session-rating of perceived exertion (RPE) method for quantifying internal TL in competitive swimmers using heart rate (HR)-based methods and distance as criterion measures. This study also examined the correspondence between athlete and coach perceptions of internal TL using the session-RPE method. Twelve (six male, six female) well-trained swimmers (mean +/- SD: age 22.3 +/- 3.1 years, weight 71.8 +/- 11.6 kg, height 175.0 +/- 9.0 cm) participated in this study. All subjects completed a swimming step test to evaluate individual HR zones and blood lactate profile before undertaking 20 swim training sessions where RPE, HR, and distance covered were recorded. Training load was then calculated for each session using the session-RPE, HR-based methods, and session distance. The session-RPE scores were correlated to HR-based methods for measuring internal TL as well as training distance for each swimmer. All individual correlations between session-RPE, HR-based methods (r = 0.55-0.94; p < 0.05), and distance measures (r = 0.37-0.81; p < 0.05) were significant. Two-way ANOVA showed that there was a significant interaction for training intensity x coach-athlete perception, indicating that coach RPE was lower than athlete RPE for low-intensity sessions and higher than athlete RPE at high-intensity sessions. The results of this study suggest that session-RPE may provide a practical, noninvasive method for quantifying internal TL in competitive swimmers.

Practical tests for monitoring performance, fatigue and recovery in triathletes.

Few studies have described simple tests which can be used to provide an early warning of overreaching. The purpose of this study was to examine selected practical tests for monitoring changes in performance, fatigue and recovery of endurance athletes. Sixteen male triathletes were randomly assigned into matched groups. The normal training (NT) and intensified training (IT) groups completed 4 weeks of training followed by a 2-week taper. Physiological measures were taken pre- and post-overload and post-taper periods during an incremental treadmill test to exhaustion. Performance was assessed weekly using a 3-km run time trial (3 kmTT). Five-bound jump for distance (5BT) and submaximal running heart rate (HR(submax)) test were measured twice weekly and the Daily Analyses of Life Demands for Athletes (DALDA) were recorded. During the overload training period, the IT group completed approximately 290% more training load than the NT group (p<0.001). After the overload training period, 3kmTT in the IT group was reduced compared to both pre-training (3.7%, p<0.05) and the NT group (6.8%, p<0.05). 5BT was decreased by 7.9% in the IT group following the overload period (p<0.05). The IT group also demonstrated increases in stress reaction symptoms from the DALDA. Following the taper, the IT group improved 3 kmTT. In contrast, the performance, physiological and psychological markers of NT group remained relatively unchanged throughout the 6-week training period. There were weak significant correlations between weekly changes in 3 kmTT and 5BT (r=-0.37, p<0.01). The DALDA and 5BT may be practical tests for assessing changes in performance, fatigue and recovery of endurance athletes.

Physiological determinants of three-kilometer running performance in experienced triathletes.

The present investigation examined the physiological parameters that contribute to 3-km running performance. Following 2 familiarization sessions, 16 experienced male triathletes (Vo(2)max = 55.7 +/- 4.9 ml.kg(-1).min(-1), age = 31.3 +/- 11.7 years) performed a 3-km time trial (3kmTT) and were assessed for selected physiological and anthropometrical characteristics. Stepwise multiple regression and correlation analysis was used to determine the variables that significantly related to 3kmTT. The analysis revealed that 82.3% of the adjusted variance in 3kmTT performance could be explained by peak treadmill running velocity during a Vo(2)max test (Vmax) alone. The addition of the running velocity at lactate threshold (LT(vel)) and peak lactate concentration ([BLa(-)](peak)) to the prediction equation allowed for 93.6% of the adjusted variance in 3kmTT to be predicted (Y = -13.64 Vmax - 25.61 LT(vel) - 5.40 [BLa(-)](peak) + 1358.5). Correlation analysis revealed that Vmax (r = -0.91), LT(vel) (r = -0.90), and Vo(2)max (r = -0.80) were significantly related to running performance. These results show that Vmax was the single best predictor of 3-km running performance in experienced male triathletes and that both aerobic and anaerobic abilities are related to improved 3kmTT performance. Since the assessment of Vmax is relatively simple to implement, we suggest that determining Vmax may be a practical method for monitoring performance changes in short-term endurance running events.