The Positive Effects of Priming Exercise on Oxygen Uptake Kinetics and High-Intensity Exercise Performance Are Not Magnified by a Fast-Start Pacing Strategy in Trained Cyclists

The purpose of this study was to determine both the independent and additive effects of prior heavy-intensity exercise and pacing strategies on the VO2 kinetics and performance during high-intensity exercise. Fourteen endurance cyclists (VO₂max  = 62.8±8.5 mL.kg⁻¹.min⁻¹) volunteered to participate in the present study with the following protocols: 1) incremental test to determine lactate threshold and VO₂max; 2) four maximal constant-load tests to estimate critical power; 3) six bouts of exercise, using a fast-start (FS), even-start (ES) or slow-start (SS) pacing strategy, with and without a preceding heavy-intensity exercise session (i.e., 90% critical power). In all conditions, the subjects completed an all-out sprint during the final 60 s of the test as a measure of the performance. For the control condition, the mean response time was significantly shorter (p<0.001) for FS (27±4 s) than for ES (32±5 s) and SS (32±6 s). After the prior exercise, the mean response time was not significantly different among the paced conditions (FS = 24±5 s; ES = 25±5 s; SS = 26±5 s). The end-sprint performance (i.e., mean power output) was only improved (∼3.2%, p<0.01) by prior exercise. Thus, in trained endurance cyclists, an FS pacing strategy does not magnify the positive effects of priming exercise on the overall VO2 kinetics and short-term high-intensity performance.     

Fat Oxidation,Fitness and Skeletal Muscle Expression of Oxidative/Lipid Metabolism Genes in South Asians: Implications for Insulin Resistance?

Background

South Asians are more insulin resistant than Europeans, which cannot be fully explained by differences in adiposity. We investigated whether differences in oxidative capacity and capacity for fatty acid utilisation in South Asians might contribute, using a range of whole-body and skeletal muscle measures.

Methodology/Principal Findings

Twenty men of South Asian ethnic origin and 20 age and BMI-matched men of white European descent underwent exercise and metabolic testing and provided a muscle biopsy to determine expression of oxidative and lipid metabolism genes and of insulin signalling proteins. In analyses adjusted for age, BMI, fat mass and physical activity, South Asians, compared to Europeans, exhibited; reduced insulin sensitivity by 26% (p = 0.010); lower VO_2max (40.6±6.6 vs 52.4±5.7 ml.kg⁻¹.min⁻¹, p = 0.001); and reduced fat oxidation during submaximal exercise at the same relative (3.77±2.02 vs 6.55±2.60 mg.kg⁻¹.min⁻¹ at 55% VO_2max, p = 0.013), and absolute (3.46±2.20 vs 6.00±1.93 mg.kg⁻¹.min⁻¹ at 25 ml O₂.kg⁻¹.min⁻¹, p = 0.021), exercise intensities. South Asians exhibited significantly higher skeletal muscle gene expression of CPT1A and FASN and significantly lower skeletal muscle protein expression of PI3K and PKB Ser473 phosphorylation. Fat oxidation during submaximal exercise and VO_2max both correlated significantly with insulin sensitivity index and PKB Ser473 phosphorylation, with VO_2max or fat oxidation during exercise explaining 10–13% of the variance in insulin sensitivity index, independent of age, body composition and physical activity.

Conclusions/Significance

These data indicate that reduced oxidative capacity and capacity for fatty acid utilisation at the whole body level are key features of the insulin resistant phenotype observed in South Asians, but that this is not the consequence of reduced skeletal muscle expression of oxidative and lipid metabolism genes.     

Telomere Length and Long-Term Endurance Exercise: Does Exercise Training Affect Biological Age? A Pilot Study

Background

Telomeres are potential markers of mitotic cellular age and are associated with physical ageing process. Long-term endurance training and higher aerobic exercise capacity (VO_2max) are associated with improved survival, and dynamic effects of exercise are evident with ageing. However, the association of telomere length with exercise training and VO_2max has so far been inconsistent. Our aim was to assess whether muscle telomere length is associated with endurance exercise training and VO_2max in younger and older people.

Methods

Twenty men; 10 young (22–27 years) and 10 old (66–77 years), were studied in this cross-sectional study. Five out of 10 young adults and 5 out of 10 older were endurance athletes, while other halves were exercising at a medium level of activity. Mean telomere length was measured as telomere/single copy gene-ratio (T/S-ratio) using quantitative real time polymerase chain reaction. VO_2max was measured directly running on a treadmill.

Results

Older endurance trained athletes had longer telomere length compared with older people with medium activity levels (T/S ratio 1.12±0.1 vs. 0.92±0.2, p = 0.04). Telomere length of young endurance trained athletes was not different than young non-athletes (1.47±0.2 vs. 1.33±0.1, p = 0.12). Overall, there was a positive association between T/S ratio and VO_2max (r = 0.70, p = 0.001). Among endurance trained athletes, we found a strong correlation between VO_2max and T/S ratio (r = 0.78, p = 0.02). However, corresponding association among non-athlete participants was relatively weak (r = 0.58, p = 0.09).

Conclusion

Our data suggest that VO_2max is positively associated with telomere length, and we found that long-term endurance exercise training may provide a protective effect on muscle telomere length in older people.     

THE COMPETITIVE DEMANDS OF ELITE MALE RINK HOCKEY

The aim of this study was to simulate the activity pattern of rink hockey by designing a specific skate test (ST) to study the energy expenditure and metabolic responses to this intermittent high-intensity exercise and extrapolate the results from the test to competition. Six rink hockey players performed, in three phases, the 20-metre multi-stage shuttle roller skate test, a tournament match and the ST. Heart rate was monitored in all three phases. Blood lactate, oxygen consumption, ventilation and respiratory exchange ratio were also recorded during the ST. Peak HR was 190.7±7.2 beats · min⁻¹. There were no differences in peak HR between the three tests. Mean HR was similar between the ST and the match (86% and 87% of HR_max, respectively). Peak and mean ventilation averaged 111.0±8.8 L · min⁻¹ and 70.3±14.0 L ^· min⁻¹ (60% of V_Emax), respectively. VO_2max was 56.3±8.4 mL · kg⁻¹ · min⁻¹, and mean oxygen consumption was 40.9±7.9 mL · kg^{−1 ·} min⁻¹ (70% of VO_2max). Maximum blood lactate concentration was 7.2±1.3 mmol · L-1. ST yielded an energy expenditure of 899.1±232.9 kJ, and energy power was 59.9±15.5 kJ · min⁻¹. These findings suggest that the ST is suitable for estimating the physiological demands of competitive rink hockey, which places a heavy demand on the aerobic and anaerobic systems, and requires high energy consumption.     

Validity of Cooper’s 12-minute run test for estimation of maximum oxygen uptake in male university students

The present study was conducted to validate the applicability of Cooper''s 12-minute run test (CRT) for predicting VO₂max in male university students of Kolkata, India, to bypass the exhaustive and complicated protocol of direct estimation of VO₂max. Eighty-eight sedentary male university students recruited by simple random sampling from the University of Calcutta, Kolkata, were randomly assigned to the study group (N = 58) and the confirmatory group (N = 30). VO₂max of each participant was determined by the direct procedure and the indirect CRT method. The mean value of predicted VO₂max (PVO₂max) (42.8±4.0 ml · kg⁻¹ · min⁻¹ with a range of 33.7–50.9) showed a significant difference with VO₂max (39.8±4.0 ml · kg⁻¹ · min⁻¹ with a range of 33.5–47.7) in the study group. Limits of agreement between PVO₂max and VO₂max were large enough (0.10 to 5.94 ml · kg⁻¹ · min⁻¹) with poor confidence intervals indicating inapplicability of the current protocol of CRT in the studied population. The prediction norm [Y = 21.01X – 11.04 (SEE = 0.193 ml · kg⁻¹ · min⁻¹)] was computed from the significant correlation (r = 0.93, P < 0.001) between distance covered in CRT and VO₂max. Application of this norm in the confirmatory group revealed an insignificant difference between PVO₂max and VO₂max. The modified equation is recommended for application of CRT as a valid method to evaluate the cardiorespiratory fitness in terms of VO₂max in sedentary male Indian youth.     

Cardiorespiratory Optimal Point: A Submaximal Exercise Variable to Assess Panic Disorder Patients

Panic disorder (PD) patients often report respiratory symptoms and tend to perform poorly during maximal cardiopulmonary exercise testing (CPX), at least partially, due to phobic anxiety. Thus, we hypothesized that a submaximal exercise variable, minimum VE/VO₂ - hereafter named cardiorespiratory optimal point (COP) -, may be useful in their clinical assessment. Data from 2,338 subjects were retrospectively analyzed and 52 (2.2%) patients diagnosed with PD (PDG) (70% women; aged 48±13 years). PD patients were compared with a healthy control group (CG) precisely matched to number of cases, age and gender profiles. PDG was further divided into two subgroups, based on having achieved a maximal or a submaximal CPX (unwilling to continue until exhaustion). We compared COP, VO₂ max, maximum heart rate (HR max) between PDG and CG, and also COP between maximal and submaximal PD subgroups. COP was similar between PDG and CG (21.9±0.5 vs. 23.4±0.6; p = 0.07), as well as, for PD subgroups of maximal and submaximal CPX (22.0±0.5 vs. 21.6±1.3; p = 0.746). Additionally, PD patients completing a maximal CPX obtained VO₂ max (mL.kg−1.min−1) (32.9±1.57 vs 29.6±1.48; p = 0.145) and HR max (bpm) similar to controls (173±2.0 vs 168±2.7; p = 0.178). No adverse complications occurred during CPX. Although clinically safe, it is sometimes difficult to obtain a true maximal CPX in PD patients. Normalcy of cardiorespiratory interaction at submaximal effort as assessed by COP may contribute to reassure both patients and physicians that there is no physiological substrate for exercise-related respiratory symptoms often reported by PD patients.     

A Prospective Population Study of Resting Heart Rate and Peak Oxygen Uptake (the HUNT Study,Norway)

Objectives

We assessed the prospective association of resting heart rate (RHR) at baseline with peak oxygen uptake (VO_2peak) 23 years later, and evaluated whether physical activity (PA) could modify this association.

Background

Both RHR and VO_2peak are strong and independent predictors of cardiovascular morbidity and mortality. However, the association of RHR with VO_2peak and modifying effect of PA have not been prospectively assessed in population studies.

Methods

In 807 men and 810 women free from cardiovascular disease both at baseline (1984–86) and follow-up 23 years later, RHR was recorded at both occasions, and VO_2peak was measured by ergospirometry at follow-up. We used Generalized Linear Models to assess the association of baseline RHR with VO_2peak, and to study combined effects of RHR and self-reported PA on later VO_2peak.

Results

There was an inverse association of RHR at baseline with VO_2peak (p<0.01). Men and women with baseline RHR greater than 80 bpm had 4.6 mL·kg⁻¹·min⁻¹ (95% confidence interval [CI], 2.8 to 6.3) and 1.4 mL·kg⁻¹·min⁻¹ (95% CI, −0.4 to 3.1) lower VO_2peak at follow-up compared with men and women with RHR below 60 bpm at baseline. We found a linear association of change in RHR with VO_2peak (p = 0.03), suggesting that a decrease in RHR over time is likely to be beneficial for cardiovascular fitness. Participants with low RHR and high PA at baseline had higher VO_2peak than inactive people with relatively high RHR. However, among participants with relatively high RHR and high PA at baseline, VO_2peak was similar to inactive people with relatively low RHR.

Conclusion

RHR is an important predictor of VO_2peak, and serial assessments of RHR may provide useful and inexpensive information on cardiovascular fitness. The results suggest that high levels of PA may compensate for the lower VO_2peak associated with a high RHR.     

PHYSIOLOGICAL DEMANDS OF YOUNG WOMEN'S COMPETITIVE GYMNASTIC ROUTINES

The objective of this study was to investigate the physiological indices of competitive routines in women''s artistic gymnastics by characterizing post-exercise heart rate (HR), oxygen uptake (VO₂) and peak blood lactate concentration (L_max) in a group of eight young elite-oriented female gymnasts. HR was continuously monitored with Polar RS400 monitors during the test event simulating a competition environment. Within 5 s of the end of each routine, the breath-by-breath gas analyser mask was placed on the face to record VO₂. VO₂max was calculated by the backward extrapolation method of the VO₂ recovery curve. L_max was obtained during recovery (min 1, 3, 5, 7 and 10) subsequent to each event. One week later, HR, VO₂ and L_max were measured during an incremental continuous treadmill test. The treadmill test was confirmed as the assessment with the highest physiological demand. The gymnasts reached their highest values of HR (183-199 beats · min^-1), VO₂/Bm (33-44 ml · kg^-1 · min^-1) and L_max (7-9 mmol · l^-1) in the floor and uneven bars exercises. The vault was the event with the lowest HR (154-166 beats · min^-1) and L_max (2.4-2.6 mmol · l^-1), and the balance beam had the lowest VO₂ (27-35 ml · kg^-1 · min^-1). The mean relative peak intensities attained in the different events, which ranged from 65 to 85% of the individual VO₂max and HRmax recorded in the laboratory, suggest that cardiorespiratory and metabolic demands are higher than previously indicated. The high percentage of VO₂ measured, particularly after the floor event, suggests that aerobic power training should not be neglected in women''s artistic gymnastics.     

The Metabolic and Performance Effects of Caffeine Compared to Coffee during Endurance Exercise

There is consistent evidence supporting the ergogenic effects of caffeine for endurance based exercise. However, whether caffeine ingested through coffee has the same effects is still subject to debate. The primary aim of the study was to investigate the performance enhancing effects of caffeine and coffee using a time trial performance test, while also investigating the metabolic effects of caffeine and coffee. In a single-blind, crossover, randomised counter-balanced study design, eight trained male cyclists/triathletes (Mean±SD: Age 41±7y, Height 1.80±0.04 m, Weight 78.9±4.1 kg, VO₂ max 58±3 ml•kg⁻¹•min⁻¹) completed 30 min of steady-state (SS) cycling at approximately 55% VO₂max followed by a 45 min energy based target time trial (TT). One hour prior to exercise each athlete consumed drinks consisting of caffeine (5 mg CAF/kg BW), instant coffee (5 mg CAF/kg BW), instant decaffeinated coffee or placebo. The set workloads produced similar relative exercise intensities during the SS for all drinks, with no observed difference in carbohydrate or fat oxidation. Performance times during the TT were significantly faster (∼5.0%) for both caffeine and coffee when compared to placebo and decaf (38.35±1.53, 38.27±1.80, 40.23±1.98, 40.31±1.22 min respectively, p<0.05). The significantly faster performance times were similar for both caffeine and coffee. Average power for caffeine and coffee during the TT was significantly greater when compared to placebo and decaf (294±21 W, 291±22 W, 277±14 W, 276±23 W respectively, p<0.05). No significant differences were observed between placebo and decaf during the TT. The present study illustrates that both caffeine (5 mg/kg/BW) and coffee (5 mg/kg/BW) consumed 1 h prior to exercise can improve endurance exercise performance.     

Aerobic and anaerobic determinants of repeated sprint ability in team sports athletes

The aim of this study was to examine in team sports athletes the relationship between repeated sprint ability (RSA) indices and both aerobic and anaerobic fitness components. Sixteen team-sport players were included (age, 23.4 ± 2.3 years; weight, 71.2 ± 8.3 kg; height, 178 ± 7 cm; body mass index, 22.4 ± 2 kg · m⁻²; estimated VO₂max, 54.16 ± 3.5 mL · kg⁻¹ · min⁻¹). Subjects were licensed in various team sports: soccer (n = 8), basketball (n = 5), and handball (n = 3). They performed 4 tests: the 20 m multi-stage shuttle run test (MSRT), the 30-s Wingate test (WingT), the Maximal Anaerobic Shuttle Running Test (MASRT), and the RSA test (10 repetitions of 30 m shuttle sprints (15 + 15 m with 180° change of direction) with 30 s passive recovery in between). Pearson''s product moment of correlation among the different physical tests was performed. No significant correlations were found between any RSA test indices and WingT. However, negative correlations were found between MASRT and RSA total sprint time (TT) and fatigue index (FI) (r = -0.53, p < 0.05 and r = -0.65, p < 0.01, respectively). No significant relationship between VO₂max and RSA peak sprint time (PT) and total sprint time (TT) was found. Nevertheless, VO₂max was significantly correlated with the RSA FI (r = -0.57, p < 0.05). In conclusion, aerobic fitness is an important factor influencing the ability to resist fatigue during RSA exercise. Our results highlighted the usefulness of MASRT, in contrast to WingT, as a specific anaerobic testing procedure to identify the anaerobic energy system contribution during RSA.     

A Limited Role for PI(3,4,5)P3 Regulation in Controlling Skeletal Muscle Mass in Response to Resistance Exercise

Background

Since activation of the PI3K/(protein kinase B; PKB/akt) pathway has been shown to alter muscle mass and growth, the aim of this study was to determine whether resistance exercise increased insulin like growth factor (IGF) I/phosphoinositide 3-kinase (PI3K) signalling and whether altering PI(3,4,5)P₃ metabolism genetically would increase load induced muscle growth.

Methodology/Principal Findings

Acute and chronic resistance exercise in wild type and muscle specific PTEN knockout mice were used to address the role of PI(3,4,5)P₃ regulation in the development of skeletal muscle hypertrophy. Acute resistance exercise did not increase either IGF-1 receptor phosphorylation or IRS1/2 associated p85. Since insulin/IGF signalling to PI3K was unchanged, we next sought to determine whether inactivation of PTEN played a role in load-induced muscle growth. Muscle specific knockout of PTEN resulted in small but significant increases in heart (PTEN^+/+  = 5.00±0.02 mg/g, PTEN^−/−  = 5.50±0.09 mg/g), and TA (PTEN^+/+  = 1.74±0.04 mg/g, PTEN^−/−  = 1.89 ±0.03) muscle mass, while the GTN, SOL, EDL and PLN remain unchanged. Following ablation, hypertrophy of the PLN, SOL or EDL muscles was similar between PTEN^−/− and PTEN^+/+ animals. Even though there were some changes in overload-induced PKB and S6K1 phosphorylation, 1 hr following acute resistance exercise there was no difference in the phosphorylation state of S6K1 Thr389 between genotypes.

Conclusions/Significance

These data suggest that physiological loading does not lead to the enhanced activation of the PI3K/PKB/mTORC1 axis and that neither PI3K activation nor PTEN, and by extension PI(3,4,5)P₃ levels, play a significant role in adult skeletal muscle growth.     

Comparison of “Live High-Train Low” in Normobaric versus Hypobaric Hypoxia

We investigated the changes in both performance and selected physiological parameters following a Live High-Train Low (LHTL) altitude camp in either normobaric hypoxia (NH) or hypobaric hypoxia (HH) replicating current “real” practices of endurance athletes. Well-trained triathletes were split into two groups (NH, n = 14 and HH, n = 13) and completed an 18-d LHTL camp during which they trained at 1100–1200 m and resided at an altitude of 2250 m (P_iO₂  = 121.7±1.2 vs. 121.4±0.9 mmHg) under either NH (hypoxic chamber; F_iO₂ 15.8±0.8%) or HH (real altitude; barometric pressure 580±23 mmHg) conditions. Oxygen saturations (S_pO₂) were recorded continuously daily overnight. P_iO₂ and training loads were matched daily. Before (Pre-) and 1 day after (Post-) LHTL, blood samples, VO_2max, and total haemoglobin mass (Hb_mass) were measured. A 3-km running test was performed near sea level twice before, and 1, 7, and 21 days following LHTL. During LHTL, hypoxic exposure was lower for the NH group than for the HH group (220 vs. 300 h; P<0.001). Night S_pO₂ was higher (92.1±0.3 vs. 90.9±0.3%, P<0.001), and breathing frequency was lower in the NH group compared with the HH group (13.9±2.1 vs. 15.5±1.5 breath.min⁻¹, P<0.05). Immediately following LHTL, similar increases in VO_2max (6.1±6.8 vs. 5.2±4.8%) and Hb_mass (2.6±1.9 vs. 3.4±2.1%) were observed in NH and HH groups, respectively, while 3-km performance was not improved. However, 21 days following the LHTL intervention, 3-km run time was significantly faster in the HH (3.3±3.6%; P<0.05) versus the NH (1.2±2.9%; ns) group. In conclusion, the greater degree of race performance enhancement by day 21 after an 18-d LHTL camp in the HH group was likely induced by a larger hypoxic dose. However, one cannot rule out other factors including differences in sleeping desaturations and breathing patterns, thus suggesting higher hypoxic stimuli in the HH group.     

PPARA Intron Polymorphism Associated with Power Performance in 30-s Anaerobic Wingate Test

To date, polymorphisms in several genes have been associated with a strength/power performance including alpha 3 actinin, ciliary neurotrophic factor, vitamin D receptor, or angiotensin I converting enzyme, underlining the importance of genetic component of the multifactorial strength/power-related phenotypes. The single nucleotide variation in peroxisome proliferator-activated receptor alpha gene (PPARA) intron 7 G/C (rs4253778; g.46630634G>C) has been repeatedly found to play a significant role in response to different types of physical activity. We investigated the effect of PPARA intron 7 G/C polymorphism specifically on anaerobic power output in a group of 77 elite male Czech ice hockey players (18–36 y). We determined the relative peak power per body weight (P_max.kg⁻¹) and relative peak power per fat free mass (W.kg⁻¹ _FFM) during the 30-second Wingate Test (WT30) on bicycle ergometer (Monark 894E Peak bike, MONARK, Sweden). All WT30s were performed during the hockey season. Overall genotype frequencies were 50.6% GG homozygotes, 40.3% CG heterozygotes, and 9.1% CC homozygotes. We found statistically significant differences in P_max.kg⁻¹ and marginally significant differences in P_max.kg⁻¹ _FFM values in WT30 between carriers and non-carriers for C allele (14.6±0.2 vs. 13.9±0.3 W.kg⁻¹ and 15.8±0.2 vs. 15.2±0.3 W.kg⁻¹ _FFM, P = 0.036 and 0.12, respectively). Furthermore, P_max.kg⁻¹ _FFM strongly positively correlated with the body weight only in individuals with GG genotypes (R = 0.55; p<0.001). Our results indicate that PPARA 7C carriers exhibited higher speed strength measures in WT30. We hypothesize that C allele carriers within the cohort of trained individuals may possess a metabolic advantage towards anaerobic metabolism.     

Individual Responses to Completion of Short-Term and Chronic Interval Training: A Retrospective Study

Alterations in maximal oxygen uptake (VO₂max), heart rate (HR), and fat oxidation occur in response to chronic endurance training. However, many studies report frequent incidence of “non-responders” who do not adapt to continuous moderate exercise. Whether this is the case in response to high intensity interval training (HIT), which elicits similar adaptations as endurance training, is unknown. The aim of this retrospective study was to examine individual responses to two paradigms of interval training. In the first study (study 1), twenty active men and women (age and baseline VO₂max = 24.0±4.6 yr and 42.8±4.8 mL/kg/min) performed 6 d of sprint interval training (SIT) consisting of 4–6 Wingate tests per day, while in a separate study (study 2), 20 sedentary women (age and baseline VO₂max = 23.7±6.2 yr and 30.0±4.9 mL/kg/min) performed 12 wk of high-volume HIT at workloads ranging from 60–90% maximal workload. Individual changes in VO₂max, HR, and fat oxidation were examined in each study, and multiple regression analysis was used to identify predictors of training adaptations to SIT and HIT. Data showed high frequency of increased VO₂max (95%) and attenuated exercise HR (85%) in response to HIT, and low frequency of response for VO₂max (65%) and exercise HR (55%) via SIT. Frequency of improved fat oxidation was similar (60–65%) across regimens. Only one participant across both interventions showed non-response for all variables. Baseline values of VO₂max, exercise HR, respiratory exchange ratio, and body fat were significant predictors of adaptations to interval training. Frequency of positive responses to interval training seems to be greater in response to prolonged, higher volume interval training compared to similar durations of endurance training.     

Physiological,physical and on-ice performance criteria for selection of elite ice hockey teams

The purpose of this study was to examine physiological and physical determinants of ice-hockey performance in order to assess their impact on the result during a selection for ice hockey. A total of 42 ice hockey players took part in the selection camp. At the end of the camp 20 best players were selected by team of expert coaches to the ice hockey team and created group G1, while the second group (G2) consisted of not selected players (non-successful group Evaluation of goodness of fit of the model to the data was based on the Hosmer Lemeshow test. Ice hockey players selected to the team were taller 181.95±4.02 cm, had lower% body fat 13.17±3.17%, a shorter time to peak power 2.47±0.35 s, higher relative peak power 21.34±2.41 W·kg⁻¹ and higher relative total work 305.18±28.41 J·kg⁻¹. The results of the aerobic capacity test showed significant differences only in case of two variables. Ice hockey players in the G1 had higher VO₂max 4.07±0.31 l·min⁻¹ values than players in the G2 as well as ice hockey players in G1 showed a higher level of relative VO₂max 51.75±2.99 ml·min⁻¹·kg⁻¹ than athletes in G2. Ice hockey players selected to the team (G1) performed better in the 30 m Forwards Sprint 4.28±0.31 s; 6x9 Turns 12.19±0.75 s; 6x9 stops 12.79±0.49 s and Endurance test (6x30 m stops) 32.01±0.80 s than players in G2. The logistic regression model showed that the best predictors of success in the recruitment process of top level ice hockey players were time to peak power, relative peak power, VO₂max and 30 m sprint forwards on ice. On the basis of the constructed predictive logistic regression model it will be possible to determine the probability of success of the athletes during following the selection processes to the team.     

Aerobic Capacity,Activity Levels and Daily Energy Expenditure in Male and Female Adolescents of the Kenyan Nandi Sub-Group

The relative importance of genetic and socio-cultural influences contributing to the success of east Africans in endurance athletics remains unknown in part because the pre-training phenotype of this population remains incompletely assessed. Here cardiopulmonary fitness, physical activity levels, distance travelled to school and daily energy expenditure in 15 habitually active male (13.9±1.6 years) and 15 habitually active female (13.9±1.2) adolescents from a rural Nandi primary school are assessed. Aerobic capacity () was evaluated during two maximal discontinuous incremental exercise tests; physical activity using accelerometry combined with a global positioning system; and energy expenditure using the doubly labelled water method. The of the male and female adolescents were 73.9±5.7 ml^. kg^−1. min⁻¹ and 61.5±6.3 ml^. kg^−1. min⁻¹, respectively. Total time spent in sedentary, light, moderate and vigorous physical activities per day was 406±63 min (50% of total monitored time), 244±56 min (30%), 75±18 min (9%) and 82±30 min (10%). Average total daily distance travelled to and from school was 7.5±3.0 km (0.8–13.4 km). Mean daily energy expenditure, activity-induced energy expenditure and physical activity level was 12.2±3.4 MJ^. day⁻¹, 5.4±3.0 MJ^. day⁻¹ and 2.2±0.6. 70.6% of the variation in was explained by sex (partial R² = 54.7%) and body mass index (partial R² = 15.9%). Energy expenditure and physical activity variables did not predict variation in once sex had been accounted for. The highly active and energy-demanding lifestyle of rural Kenyan adolescents may account for their exceptional aerobic fitness and collectively prime them for later training and athletic success.     

Correlation of Standardized Uptake Value and Apparent Diffusion Coefficient in Integrated Whole-Body PET/MRI of Primary and Recurrent Cervical Cancer

Background

To evaluate a potential correlation of the maximum standard uptake value (SUV_max) and the minimum apparent diffusion coefficient (ADC_min) in primary and recurrent cervical cancer based on integrated PET/MRI examinations.

Methods

19 consecutive patients (mean age 51.6 years; range 30–72 years) with histopathologically confirmed primary cervical cancer (n = 9) or suspected tumor recurrence (n = 10) were prospectively enrolled for an integrated PET/MRI examination. Two radiologists performed a consensus reading in random order, using a dedicated post-processing software. Polygonal regions of interest (ROI) covering the entire tumor lesions were drawn into PET/MR images to assess SUV_max and into ADC parameter maps to determine ADC_min values. Pearson’s correlation coefficients were calculated to assess a potential correlation between the mean values of ADC_min and SUV_max.

Results

In 15 out of 19 patients cervical cancer lesions (n = 12) or lymph node metastases (n = 42) were detected. Mean SUV_max (12.5±6.5) and ADC_min (644.5±179.7×10⁻⁵ mm²/s) values for all assessed tumor lesions showed a significant but weak inverse correlation (R = −0.342, p<0.05). When subdivided in primary and recurrent tumors, primary tumors and associated primary lymph node metastases revealed a significant and strong inverse correlation between SUV_max and ADC_min (R = −0.692, p<0.001), whereas recurrent cancer lesions did not show a significant correlation.

Conclusions

These initial results of this emerging hybrid imaging technique demonstrate the high diagnostic potential of simultaneous PET/MR imaging for the assessment of functional biomarkers, revealing a significant and strong correlation of tumor metabolism and higher cellularity in cervical cancer lesions.