Physiological characteristics and performance of a world-record breaking tower runner.

This study reports the physiological and performance profiles of a world-class tower runner during a 6-week period surrounding a successful Guinness World Record (WR) attempt, and discusses the efficacy of a tower running specific field test. The world-ranked number 2 tower runner completed four exercise tests [laboratory treadmill assessment (3 weeks before the WR attempt), familiarisation to a specific incremental tower running field test (1 week before), tower running field test (1 week after), and tower running time trial (TT) (3 weeks after)] and the WR attempt within 6-week period. Peak oxygen consumption (VO2peak) during the laboratory test, field test, and TT were 73.3, 75.5 and 78.3 mL·kg-1·min-1, respectively. The VO2 corresponding to the second ventilatory threshold was 67.3 mL·kg-1·min-1 (89.1% of VO2peak), identified at stage 4 (tempo; 100 b·min-1), during the field test. The duration of the TT was 10 min 50 s, with an average VO2 of 71.7 mL·kg-1·min-1 (91.6% of VO2peak), HR of 171 b·min-1 (92% of peak HR), vertical speed of 0.47 m·s-1, and cadence was 117 steps·min-1. A world-class tower runner possesses a well-developed aerobic capacity. A specific, field-based test revealed greater VO2peak than a laboratory test, indicating a need for sport-specific testing procedures.

Determination of the speed-time relationship during handcycling in spinal cord injured athletes.

This study aimed to determine the critical speed (CS) and the work above CS (D') from three mathematical models of para-athletes during a treadmill handcycling exercise. Nine hand-cyclists with spinal cord injuries performed a maximal incremental handcycling test and three tests to exhaustion at a constant speed to determine the speed-time relationship. The three tests to exhaustion were performed at intensities between 90% and 105% of peak speed derived from the incremental test. Then, the determination of CS and D' was modelled by linear and hyperbolic models. CS and D' did not present any significant differences among the three mathematical models. Low values in the standard error of estimate for CS were found for the three models (Linear: Distance-time: 1.7 ± 0.5%; Linear: Speed-1/time: 3.0 ± 1.9% and Hyperbolic: 1.2 ± 0.6%). Based on the simplicity to calculate, the CS modelled by linear-distance-time can be a practical method for handcyclist coaches.

Positional Differences in GPS Outputs and Perceived Exertion During Soccer Training Games and Competition.

Abbott, W, Brickley, G, and Smeeton, NJ. Positional differences in GPS outputs and perceived exertion during soccer training games and competition. J Strength Cond Res 32(11): 3222-3231, 2018-Soccer training games are popular training modalities, allowing technical, tactical, and physical aspects to be trained simultaneously. Small (SSGs), medium (MSGs), and large training games (LSGs) elicit differing physical demands. To date, no research has investigated physical and perceived demands of training games on soccer playing positions relative to competitive demands. In addition, previous research has referenced average competitive intensities, ignoring peak demands of competition. The current aim was to investigate the effect of training game formats on average and peak physical outputs produced by soccer playing positions. Physical and perceptual data from 22 competitive matches and 39 training game sessions were collected for 46 U23 professional players using 10-Hz global positioning system (GPS) and 100-Hz accelerometer devices (MinimaxX version 4.0; Catapult Innovations, Melbourne, Australia). Data analyzed included GPS-derived distance, speed, acceleration, deceleration, and rating of perceived exertion (RPE). Two-way between-subjects analyses of variance were used to compare average and peak GPS metrics, and RPE, between training games and competition for playing positions. Despite eliciting significantly higher average total distances compared with competition (p < 0.01), LSGs produced significantly lower peak total distance relative to the competition (p < 0.01). For very high-speed running and sprinting, LSGs elicited similar average intensities to competition; however, peak intensities were significantly lower than competition (p < 0.01). Medium training games and LSGs produced significantly higher average and peak moderate-intensity explosive distances than competition (p < 0.01). Results indicate the importance of analyzing relative to peak competitive demands, instead of focusing solely on average demands. The study demonstrates that specific game formats can overload the competitive demands of playing positions and provide an individualized training stimulus.

Individualizing Acceleration in English Premier League Academy Soccer Players.

Abbott, W, Brickley, G, Smeeton, NJ, and Mills, S. Individualizing acceleration in English Premier League academy soccer players. J Strength Cond Res 32(12): 3512-3519, 2018-Global thresholds are typically used to band acceleration dependent on intensity. However, global thresholds do not account for variation in individual capacities, failing to quantify true intensity of acceleration. Previous research has investigated discrepancies in high-speed distance produced using global and individual speed thresholds, not yet investigated for acceleration. The current aim was to investigate discrepancies between global and individual thresholds when quantifying acceleration tasks. Acceleration data were recorded for 31 professional soccer players, using 10-Hz global positioning systems devices. Distances traveled performing low-, moderate-, and high-intensity acceleration were calculated for athletes using global and individual thresholds. Global acceleration thresholds for low-, moderate-, and high-intensity acceleration were classified as 1-2, 2-3, and >3 m·s, respectively, with individual thresholds classified as 25-50%, 50-75%, and >75% of maximum acceleration, respectively. Athletes were grouped low (LO), medium (ME), or high (HI) maximum accelerative capacity, determined using 3 maximal 40-m linear sprints. Two-way mixed-design analyses of variance were used to analyze differences in acceleration distances produced between analysis methods and athlete groups. No significant differences were identified between analysis methods for LO. For ME, no significant differences were demonstrated for low intensity. Moderate- and high-intensity acceleration distances were significantly higher for global compared with individual analysis method (p < 0.01). For HI, significantly higher acceleration distances were produced for all acceleration intensities using global thresholds (p < 0.01). Significant differences identified between analysis methods suggest practitioners must apply caution when using global thresholds. Global thresholds do not account for individual capacities and may provide an inaccurate representation of relative intensity of acceleration tasks.

Tissue doppler-derived contractile reserve is a simple and strong predictor of cardiopulmonary exercise performance across a range of cardiac diseases.

BACKGROUND: Resting echocardiographic measures of cardiac function such as left ventricular ejection fraction correlate poorly with exercise capacity. Assessment during exercise using measures less dependent on hemodynamic loading conditions, such as tissue Doppler imaging (TDI), may more accurately characterize the relationship between cardiac function and exercise capacity. METHODS AND RESULTS: One hundred one subjects with various cardiac diagnoses underwent exercise stress echocardiography with simultaneous cardiopulmonary gas exchange analysis. Standard two-dimensional, Doppler and spectral TDI parameters were assessed at both rest and peak exercise. Across all subjects the strongest relationship with peak oxygen uptake (pVO2 ) was with peak left ventricular systolic tissue velocity (S') during exercise (r = 0.84, P < 0.001). The strength of the relationship was greater than that observed with any other common echocardiographic measure of systolic or diastolic cardiac function. CONCLUSION: There is a very strong relationship between measurements of S' during exercise and exercise capacity. The previously observed poor correlation with standard measures of systolic and diastolic cardiac function may be explained both by the load dependence of parameters such as ejection fraction and by reliance on resting as opposed to exercise assessment.

The Relationship Between Subjective Wellness and External Training Load in Elite English Premier League Goalkeepers and a Comparison With Outfield Soccer Players.

PURPOSE: To investigate the relationship between training load and subjective wellness in English Premier League goalkeepers (GKs) and examine potential positional differences in subjective wellness. METHODS: A total of 34 players (GK = 7, outfield = 27) completed a daily subjective wellness questionnaire assessing sleep quality, sleep hours, fatigue, mood, soreness, and total wellness over two and a half seasons. Ten-Hertz GPS devices were worn during training to calculate previous-day and 7-day total distance, player load, total dives, total dive load, average time to feet, and high, medium, and low jumps. RESULTS: All previous 7-day training loads were associated with all wellness markers (r = .073 to .278, P < .05). However, associations between previous 7-day dive load and mood, average time to feet, and both sleep quality and quantity, and between low jumps and sleep quality, were not significant. For previous-day metrics, total distance was associated with all wellness markers (r = .097 to .165, P < .05). In addition, player load and high jump were associated with fatigue, soreness, and wellness (r = .096 to .189, P < .05). Total dives and soreness were also related (r = .098, P < .05), and relationships were evident between average time to feet, medium jumps, and all wellness markers excluding sleep quality (r = .114 to .185, P < .05). No positional differences in subjective wellness occurred (P > .05). CONCLUSION: Some GK GPS variables are associated with subjective wellness, which could inform training-load prescription to maximize recovery and performance. In addition, GKs are no more vulnerable to poorer subjective wellness when compared with outfield players.

The effects of injury, contextual match factors and training load upon psychological wellbeing in English Premier League soccer players via season-long tracking.

The study aimed to track psychological wellbeing (PWB) across two consecutive soccer seasons examining the effects of injury, illness, training load (TL) and contextual match factors (playing status, match selection and individual win rate). Furthermore, examine PWB prior to injury or illness event. Thirty-two English Premier League (EPL) soccer players completed the "Warwick-Edinburgh Mental Wellbeing Scale" every two weeks. No differences were found for group averaged PWB across the seasons (52.2 ± 0.3 vs. 51.8 ± 1.1) (p > 0.05). Previous 7-day TL measured using GPS (session duration, total distance, explosive distance, low-intensity distance, high-speed distance (HSD) and sprint distance (SD)) were not related to current PWB (p > 0.05). Yet, previous 14-day HSD (r (385) = -0.095) and 21-day SD (r (385) = 0.100) were related to current PWB (p < 0.05). Only 100% (vs. 0%) win rate in the previous 14-days to the questionnaire revealed a higher current PWB score (52.7 ± 4.7 vs. 50.9 ± 5.6 (p < 0.05)). PWB did not differ prior to an injury or illness event, when players were injured or had low contextual match factors at time of questionnaire or previous match, and the previous 7-days (p > 0.05). In conclusion, PWB fluctuations across the season are associated with prior TL and multiple negative results. But prior PWB was not linked to injury or illness events. Implications for prioritising interventions to improve PWB during periods of chronic high intensity TLs and losing streaks, monitoring PWB, and use in injury and illness prediction are discussed.HighlightsPsychological wellbeing responses, as measured by the "Warwick-Edinburgh Mental Wellbeing Scale" did not change significantly at a group level between the phases of the two seasons.Prior training load was associated with wellbeing scores, specifically previous 14-day high-speed distance and 21-day sprint distance.Psychological wellbeing scores were only affected by win/loss rate in the previous 14-days.These findings highlight the importance of timely interventions to improve wellbeing in periods of negative results, and the recommendation of longitudinally monitoring wellbeing.

Physical activity on mental wellbeing in senior English Premier League soccer players during the COVID-19 pandemic and the lockdown.

The COVID-19 pandemic and the subsequent lockdown created new stressors that could potentially attenuate mental wellbeing (MW) in athletes, who are already susceptible to poor MW. This study aims to describe fluctuations to MW during "lockdown" and subsequent "return to sport" protocols, in comparison to the normal "in-season" in professional soccer. Twenty-five English Premier League (EPL) soccer players completed the Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS) every two weeks, during the 2019/2020 season, and every week during "lockdown" and "return to training" for 28 weeks. The duration of each physical activity (PA) session completed was recorded. No significant differences were found for MW between time points (In-season, lockdown, return to training and the restart) (51.5 ± 5.6 vs. 50.7 ± 4.8 vs. 50.8 ± 5.7 vs. 50.7 ± 5.6 (p > 0.05)) respectively. Individually, differences were identified; in-season weekly session duration (243 ± 38 min) was higher than during lockdown (180 ± 62 min) (p < 0.05). During lockdown, weekly MW scores were related to the previous 7-day number of sessions (r = 0.151) and active min (r = 0.142) (p < 0.05). Furthermore, participants that exercised >250 min in lockdown, had higher MW scores (52.46 ± 4.65) than <250 min (50.35 ± 6.55) (p < 0.05). MW responses to lockdown were best understood on an individual basis. Additionally, PA only had a measurable effect on MW when >250 min. Further, stressors imposed upon players during an EPL season, are potentially greater than those inflicted by the lockdown. Implications for monitoring MW in EPL soccer players and the potential inclusion of an in-season break are discussed.Highlights Mental Wellbeing Responses, as measured by the Warwick-Edinburgh Mental Wellbeing scale did not change significantly at a group level across the four phases of the season. However, on an individual level changes were evident.There was a decline in the trend of wellbeing scores during in-season, return to training and the restart, but an increase in wellbeing scores during lockdown.Physical Activity had a measurable effect on wellbeing, when physical activity was >250 min during lockdown.These findings highlight the need for individual monitoring of wellbeing and longitudinal monitoring in sport to identify decline in wellbeing and implement intervention. In addition, the prescription of physical activity >250 min per week during lockdown in trained athletes may promote positive mental health.

Physiological and Perceptual Responses in Spinal Cord Injury Handcyclists During an Endurance Interval Training: The Role of Critical Speed.

OBJECTIVE: This study sought to determine the physiological (oxygen uptake, heart rate, and blood lactate concentration) and perceptual (rating of perceived exertion) responses during an endurance interval training at the critical speed in elite handcyclists with spinal cord injury. DESIGN: Eight handcyclists performed an incremental test, three tests to exhaustion at a constant speed to determine critical speed, and the endurance interval training. The endurance interval training consisted of 6 × 5 mins at the individualized critical speed, with passive recovery of 50 secs. All testing was performed using their own handcycles on an oversized motorized treadmill. Physiological and perceptual responses were assessed during the incremental and endurance interval training tests. RESULTS: There was no significant difference in average oxygen uptake from the first to the sixth repetition. The mean ∆[La-]10_last between the 10th to the 30th minute of the exercise was -0.36 mmol·l-1, and no difference was detected from the first to the sixth repetition. The heart rate also remained stable during endurance interval training, whereas rating of perceived exertion increased significantly throughout the session. CONCLUSIONS: Repetitions of 5 mins at the critical speed in elite handcyclists are associated with cardiorespiratory and lactate steady state, whereas the perceived exertion increased systematically.

Acute hypoxia and exercise improve insulin sensitivity (S(I) (2*)) in individuals with type 2 diabetes.

BACKGROUND: hypoxia has been shown to increase glucose uptake in skeletal muscle using the contraction-stimulated pathway, independent of the actions of insulin. Yet, the same stress has also been linked with causing insulin resistance and hyperglycaemia. The aim of this study was to examine the effects of acute hypoxia with and without exercise on insulin sensitivity (S(I)(2*) in individuals with type 2 diabetes. METHODS: eight type 2 diabetic patients completed 60 min of the following: (1) normoxic rest; (2) hypoxic rest [O(2) = 14.6 (0.4)%]; (3) normoxic exercise and (4) hypoxic exercise [O(2) = 14.6 (0.4)%]. Exercise trials were set at 90% of lactate threshold. Each condition was followed by a labelled intravenous glucose tolerance test to provide estimations of insulin sensitivity (S(I)(2*) and ß-cell function. RESULTS: Two-compartmental analysis showed that insulin sensitivity (S(I)(2*) was higher following hypoxic rest compared with normoxic rest (p = 0.047). Insulin sensitivity (S(I)(2*) was also higher following hypoxic exercise [4.37 (0.48) × 10(-4) /min (µU/mL)] compared with normoxic exercise [3.24 (0.51) × 10(-4) /min (µU/mL)] (p = 0.048). Acute insulin response to glucose was reduced following hypoxic rest versus normoxic rest (p = 0.014). CONCLUSIONS: this study demonstrated that (1) hypoxic-induced improvements in glucose tolerance in the 4 h following exposure can be attributed to improvements in peripheral insulin sensitivity (S( I)(2*) and (2) exercise and hypoxia have an additive effect on insulin sensitivity (S(I)(2*) in type 2 diabetic patients. Acute hypoxia may therefore improve short-term glycaemic control in individuals with type 2 diabetes. The application of these findings in the clinic will require further investigation.

The physiological and perceptual responses of stand-up paddle board exercise in a laboratory- and field-setting.

This study quantified the physiological and perceptual responses of stand-up paddle boarding (SUP) during a range of stroke rates in a laboratory- and field-setting. Ten participants (eight male, two female; mean ± standard deviation [SD] age: 23 ± 3 years; body mass: 70.5 ± 9.1 kg; height: 170 ± 9 cm; body mass index [BMI]: 24.3 ± 1.5 kg m2) completed a SUP ⩒O2peak trial, and two SUP trials in both a laboratory- and field-setting (5-min at 10, 20 and 30 strokes min-1 per stage). Energy expenditure (EE), metabolic equivalents (METs), heart rate (HR) and rating of perceived exertion (RPE) were recorded throughout. In the laboratory-setting, mean ± SD EE and METs increased (P < .001) linearly when SUP at 10 (3.3 ± 1.0 kcal min-1, 2.7 ± 0.5), 20 (5.5 ± 0.9 kcal min-1, 4.4 ± 0.7) and 30 strokes min-1 (7.6 ± 1.6 kcal min-1, 6.1 ± 1.2), respectively. During these efforts, mean ± SD percentage of maximal HR were 56 ± 5%, 69 ± 6% and 84 ± 8%, respectively. In the field-setting, mean ± SD EE and METs also increased (P < .001) linearly when SUP at 10 (3.6 ± 0.9 kcal min-1, 2.7 ± 0.9), 20 (4.3 ± 1.8 kcal min-1, 3.5 ± 1.0) and 30 strokes min-1 (6.3 ± 2.1 kcal min-1, 4.6 ± 1.4). During the three conditions, mean ± SD percentage of maximal HR were 58 ± 8%, 65 ± 7% and 73 ± 9%. SUP at ≥20 strokes min-1 in the laboratory- and field-setting meet the criteria for moderate-intensity exercise (3.0-5.9 METs). These findings may now be included in the latest Compendium of Physical Activities guidelines and offer the potential to improve cardiorespiratory fitness if SUP is undertaken regularly by young, healthy adults.

Effects of Bio-Banding upon Physical and Technical Performance during Soccer Competition: A Preliminary Analysis.

Bio-banded competition has been introduced to address the variation in physical maturity within soccer. To date, no research has investigated the effect of bio-banded competition relative to chronological competition. The current study investigated the effect of bio-banding upon physical and technical performance in elite youth soccer athletes. Twenty-five male soccer athletes (11-15 years) from an English Premier League soccer academy participated in bio-banded and chronological competition, with physical and technical performance data collected for each athlete. Athletes were between 85-90% of predicted adult stature, and sub-divided into early, on-time and late developers. For early developers, significantly more short passes, significantly less dribbles and a higher rating of perceived exertion (RPE) were evident during bio-banded competition compared to chronological competition (p < 0.05). Significantly more short passes and dribbles, and significantly fewer long passes were seen for on-time developers during bio-banded competition (p < 0.05). For late developers, significantly more tackles, and significantly fewer long passes were evident during bio-banded competition (p < 0.05). No significant differences in physical performance were identified between competition formats. Results demonstrated that bio-banded competition changed the technical demand placed upon athletes compared to chronological competition, without reducing the physical demands. Bio-banded competition can be prescribed to athletes of differing maturation groups dependent upon their specific developmental needs.

The importance of contractile reserve in predicting exercise tolerance in asymptomatic patients with severe aortic stenosis.

BACKGROUND: Mortality dramatically rises with the onset of symptoms in patients with severe aortic stenosis (AS). Surgery is indicated when symptoms become apparent or when there is ventricular decompensation. Cardiopulmonary exercise testing (CPET) in combination with exercise echocardiography can unmask symptoms and provides valuable information regarding contractile reserve. The aim of the present study was to determine the prevalence of reduced exercise tolerance and the parameters predicting adverse cardiovascular events. METHODS: Thirty-two patients with asymptomatic severe AS were included in this study. Patients were followed up as part of an enhanced surveillance clinic. RESULTS: Age was 69 ± 15.7 years, 75% of patients were male. Patients had a raised NT-ProBNP of 301 pg/mL. VO2peak was 19.5 ± 6.2 mL/kg/min. Forty-one percent of patients had a reduced %VO2peak and this predicted unplanned cardiac hospitalisation (P = 0.005). Exercise systolic longitudinal velocity (S') and age were the strongest independent predictors for VO2peak (R 2 = 0.76; P < 0.0001). Exercise S' was the strongest independent predictor for NT-ProBNP (R 2 = 0.48; P = 0.001). CONCLUSION: A large proportion of patients had a lower than predicted VO2peak. The major determinant of exercise and NT-ProBNP is the ability of the left ventricle (LV) to augment S' on exercise rather than the severity of aortic valve obstruction or resting structural remodelling of the LV. Reduced exercise tolerance and more adverse remodelling, rather than valve obstruction predicted unplanned hospitalisation. This study demonstrates that for those patients, in whom a watchful waiting is an agreed strategy, a detailed assessment should be undertaken including CPET, exercise echocardiography and biomarkers to ensure those with exercise limitation and risk of decompensation are detected early and treated appropriately.

Sodium phosphate loading improves laboratory cycling time-trial performance in trained cyclists.

Sodium phosphate loading has been reported to increase maximal oxygen uptake (6-12%), however its influence on endurance performance has been ambiguous. The aim of this study was to examine the influence of sodium phosphate loading on laboratory 16.1 km cycling time-trial performance. Six trained male cyclists (V O(2) peak, 64.1+/-2.8 ml kg(-1)min(-1); mean+/-S.D.) took part in a randomised double-blind crossover study. Upon completion of a control trial (C), participants ingested either 1g of tribasic dodecahydrate sodium phosphate (SP) or lactose placebo (P) four times daily for 6 days prior to performing a 16.1 km (10 mile) cycling time-trial under laboratory conditions. Power output and heart rate were continually recorded throughout each test, and at two points during each time-trial expired air samples and capillary blood samples were taken. There was a 14-day period between each of the supplemented time-trials. After SP loading mean power was greater than for P and C (C, 322+/-15 W; P, 317+/-16 W; SP, 347+/-19 W; ANOVA, P<0.05) and time to complete the 16.1 km was shorter than P, but not C (ANOVA, P<0.05). During the SP trial, relative to the P, mean changes were mean power output +9.8+/-8.0% (+/-95% confidence interval); time -3.0+/-2.9%. There was a tendency towards higher V O(2) after SP loading (ANOVA, P = 0.07). Heart rate, V (E), RER and blood lactate concentration were not significantly affected by SP loading. Sodium phosphate loading significantly improved mean power output and 16.1 km time-trial performance of trained cyclists under laboratory conditions with functional increases in oxygen uptake.

Effect of prior exercise above and below critical power on exercise to exhaustion.

PURPOSE: The aim of the present study was to ascertain whether the intensity of prior exercise altered the time to exhaustion at critical power (CP). METHODS: Eleven participants volunteered to take part in the study (mean +/- SD: VO2max 4.1 +/- 0.5 L x min(-1); age 30.1 +/- 7.2 yr; body mass 74.6 +/- 9.1 kg) and completed three trials to exhaustion at their CP under differing prior exercise conditions: 1) a control trial (CON); 2) a trial preceded by three 60-s efforts at 110% CP (severe); and 3) a trial preceded by three 73-s efforts at 90% CP (heavy). All trials followed a 5-min baseline at 50 W. RESULTS: Time to exhaustion was significantly lengthened after prior heavy exercise (1071 +/- 18 s) when compared with CON (973 +/- 16 s, F = 9.53, P = 0.006). However, there was no effect on TTE after prior severe exercise (967 +/- 16 s). Oxygen deficit was significantly reduced from that in CON (3.8 +/- 0.2 L) after prior heavy (3.2 +/- 0.3 L) and prior severe exercise (3.1 +/- 0.3 L, F = 10.95, P = 0.001). Concurrently, there was a significant reduction in the magnitude of the VO2 slow component (SC) in the trials with prior exercise (197 +/- 34 and 126 +/- 19 mL x min(-1) after heavy and severe exercise, respectively) when compared with CON (223 +/- 31 mL x min(-1), F = 9.62, P = 0.006). CONCLUSION: Prior heavy exercise does appear to improve the time to exhaustion at CP by approximately 10% and is associated with a reduction in the VO2 SC. However, the reduction in the SC, with no change in performance after prior severe exercise, suggests that a reduced SC may not necessarily lead to improved TTE.

Physiological responses to 90 s all out isokinetic sprint cycling in boys and men.

The purpose of this study was to compare the VO2 kinetic and mechanical power responses of boys and men to all out 90 s sprint cycle exercise. Eight boys (14.6 ± 0.3 y) and eight men (33.8 ± 6.5 y) volunteered to participate and completed a ramp test (to determine VO2peak and ventilatory threshold, VT) and then on subsequent days, two 90 s all out cycle sprints on an isokinetic cycle ergometer. During each test, breath-by-breath pulmonary gas exchange and power output were measured. Parameters from the power output profiles were derived from the average response of the two tests including peak power (PP, highest power output in 1 s), end power (EP60-90, power over the last 30 s), and mean power over the 90 s (MP90). Independent pairwise and dependent t-tests were used to compare the data from tests between adults and boys subject groups. Significant differences between adults and boys were found for absolute PP (881.4 ± 60.7 vs 533.6 ± 50.7 W), EP60-90 (288.6 ± 25.7 vs 134.3 ± 17.6 W) and MP90 (434.5 ± 27.4 vs 238.4 ± 17.3 W, p =0.001) respectively. Relative to body mass significant differences between adults and boys were found for EP60-90, MP90 and total work (p < 0.002). The boys attained 90 s VO2 values that were closer to VO2peak than their adult counterparts (93.3 ± 2.6 vs 84.9 ± 2.3 %, p = 0.03). They also demonstrated faster VO2 kinetics (10.8 ± 1.5 vs 17.6 ± 1.0 s, p < 0.01). In conclusion, during all out 90 s cycle sprinting boys were able to attain VO2 values that were closer to VO2peak and a faster time constant than adult men. These findings provide insight into the contribution and speed of response of the aerobic system during an 'anaerobic' test. Key PointsThe results of this study confirm the significant contributions of the aerobic energy systems during so called 'anaerobic tests'.Boys were able to attain VO2 values from an all out 90 s sprint cycle that were closer to their aerobic VO2 peak test than adults. More detailed studies are required to investigate the limiting factors that prevent VO2 peak being reached in an all out sprint cycle.All out tests of a duration > 30 s and coupled with gas and power analyses offer paediatric physiologists considerable scope to examine the contributions of the anaerobic and aerobic energy systems until more ethically viable methods are found.

Prognostic importance of tissue velocity imaging during exercise echocardiography in patients with systolic heart failure.

Resting echocardiography measurements are poor predictors of exercise capacity and symptoms in patients with heart failure (HF). Stress echocardiography may provide additional information and can be expressed using left ventricular ejection fraction (LVEF), or diastolic parameters (E/E'), but LVEF has some major limitations. Systolic annular velocity (S') provides a measure of longitudinal systolic function, which is relatively easy to obtain and shows a good relationship with exercise capacity. The objective of this study was to investigate the relationship among S', E/E' and LVEF obtained during stress echocardiography and both mortality and hospitalisation. A secondary objective was to compare S' measured using a simplified two-wall model. A total of 80 patients with stable HF underwent exercise stress echocardiography and simultaneous cardiopulmonary exercise testing. Volumetric and tissue velocity imaging (TVI) measurements were obtained, as was peak oxygen uptake (VO2 peak). Of the total number of patients, 11 died and 22 required cardiac hospitalisation. S' at peak exertion was a powerful predictor for death and hospitalisation. Cut-off points of 5.3 cm/s for death and 5.7 cm/s for hospitalisation provided optimum sensitivity and specificity. This study suggests that, in patients with systolic HF, S' at peak exertion calculated from the averaged spectral TVI systolic velocity of six myocardial segments, or using a simplified measure of two myocardial segments, is a powerful predictor of future events and stronger than LVEF, diastolic velocities at rest or exercise and VO2 peak. Results indicate that measuring S' during exercise echocardiography might play an important role in understanding the likelihood of adverse clinical outcomes in patients with HF.

Limitations to high intensity exercise prescription in chronic heart failure patients.

BACKGROUND: Interval training is recommended for chronic heart failure patients (CHF), but specific guidelines on setting appropriate workloads have not been fully established. The aim of this study was to compare a traditional method of interval training prescription with a protocol specifically designed for CHF. METHODS: Ten CHF and 7 healthy controls performed 2 maximal incremental cycle tests to determine interval training workload; a standard test (10Wmin(-)(1)) and a steep test (25W.10(-)(s)). Peak work rate and oxygen uptake (VO(2 peak)) were determined. Training workloads were defined as 100% standard test and 50% steep test peak work rate. RESULTS: Training workload determined from the standard test was higher than from the steep test in healthy controls (151 ± 17W vs 118 ± 13W; P<0.01), whereas in CHF there was no significant difference between methods (88 ± 10W vs 96 ± 9W; P>0.05). Steep test VO(2peak) reached 91 ± 5% of standard test VO(2 peak) in controls, and 99 ± 4% in CHF, with no significant differences between tests in either group. CONCLUSION: Prescribing interval training from a standard test results in higher workloads than from a steep test in healthy individuals, but in CHF both methods prescribe similar workloads. However it should not be assumed that the two tests can be used interchangeably for CHF. This small-sized study raises issues about interval training prescription that may be hypothesis-generating for future larger-scale studies.

Defining exercise synchrony in fit young adults: a tissue Doppler study.

OBJECTIVE: Exercise-induced changes in the synchrony of left ventricular contraction may be an important therapeutic target in heart failure. There are limited data to support the feasibility of exercise assessments. In addition, the effect of exercise on synchrony in healthy individuals is undetermined. METHODS: Eleven healthy young men underwent tissue Doppler assessments before and immediately after maximal cardiopulmonary exercise. Left ventricular synchrony was assessed using pulsed wave tissue Doppler of the lateral, septal, inferior, and anterior walls. The maximal dispersion times between the walls for onset and peak systolic velocities were used as synchrony indices. RESULTS: The proportion of the cardiac cycle taken between Q wave and time to onset or peak systolic motion was constant at rest and peak exercise. There was no significant exercise-induced change seen in either interventricular or intraventricular synchrony. CONCLUSION: Exercise synchrony assessment is technically feasible. Synchronization of cardiac contraction is maintained after maximal exercise in healthy individuals.