MAS and MANS Predicts Repeated Sprint Ability in Youth Soccer Players.

The study investigated the impact of maximal aerobic speed (MAS) and maximal anaerobic sprint (MANS) on repeated sprint ability (RSA) in soccer. METHODS: 17 amateur-to semi-professional soccer players, age 19 (± 4) years, were tested for maximal oxygen consumption (VO2max), oxygen cost of running (Cr), RSA consisting of 15·20m sprint each divided by a 100 seconds dribble track, and 40-meter sprint performance. MAS was calculated as VO2max · Cr-1, and MANS was defined as the highest velocity in the 40-meter sprint. RESULTS: There was a strong correlation between MAS and average 20-meter RSA velocity (r = 0.760; p < 0.01), and between MAS and performance decrement (r = -0.648; p < 0.01). The product of 0.5MAS + 0.5MANS exhibited the strongest correlation with RSA (r = 0.813; p < 0.01). CONCLUSION: The combination of MAS and MANS strongly predicted RSA. High-intensity aerobic interval training (HIIT) and maximal strength training (MST) are recommended to improve MAS and MANS, and could thus lead to better RSA on the soccer field.

Maximal aerobic and anaerobic power and time performance in 800 m double poling ergometer.

The purpose of this study was to investigate to what extent aerobic power (MAP), maximal anaerobic power (MANP), anaerobic capacity measured as time to exhaustion at 130% MAP (TTE), and maximal accumulated oxygen deficit (MAOD) correlated with 800 m double poling time trial performance (800TT) in a ski ergometer. A second aim was to investigate the relationship between TTE and MAOD, and to what extent TTE and MAOD would relate to anaerobic power reserve (APR). Eighteen cross-country skiers were tested for peak oxygen uptake (VO2peak) and oxygen cost of double poling to assess MAP. Peak power measurements during a 100 m TT were performed to assess MANP. TTE and an 800TT with continuous VO2 measurements were performed to assess time performance and MAOD. All tests were performed on a ski ergometer. Both MAP and MANP correlated strongly (r = - 0.936 and - 0.922, respectively, p < 0.01) with 800TT. Neither TTE nor MAOD correlated with 800TT. TTE correlated moderately with MAOD, both in mL kg-1 and in %VO2peak (r = 0.559, p < 0.05 and 0.621, p < 0.01, respectively). Both TTE and MAOD seemed to be a product of APR. These results suggest focusing on MAP and MANP, but not anaerobic capacity to explain time performance in an event with approximately 3 min duration.

Aerobic and Anaerobic Speed Predicts 800-m Running Performance in Young Recreational Runners.

The main aim was to investigate the impact of maximal aerobic speed (MAS), maximal anaerobic speed (MANS), and time to exhaustion (TTE) at 130% MAS, on 800-m running time performance (800TT). A second aim was to investigate the impact of anaerobic speed reserve (ASR), i.e., the relative difference between MAS and MANS, on TTE. A total of 22 healthy students classified as recreational runners participated in a cross-sectional study. They were tested for maximal oxygen consumption (VO2max), oxygen cost of running (CR), time performance at 100 m (100TT), time performance at 800 m (800TT), and TTE. MAS was calculated as VO2max × CR -1, and MANS was calculated as 100TT velocity. Both MAS and MANS correlated individually with 800TT (r = -0.74 and -0.67, respectively, p < 0.01), and the product of MAS and MANS correlated strongly (r = -0.82, p < 0.01) with 800TT. TTE did not correlate with 800TT. Both ASR and % MANS correlated strongly with TTE (r = 0.90 and -0.90, respectively, p < 0.01). These results showed that 800TT was first and foremost dependent on MAS and MANS, and with no impact from TTE. It seemed that TTE was merely a product of each runner's individual ASR. We suggest a simplified model of testing and training for 800TT, namely, by focusing on VO2max, CR, and short sprint velocity, i.e., MAS and MANS.

Responses to Maximal Strength Training in Different Age and Gender Groups.

PURPOSE: The present study aimed to investigate the potential impact of age, gender, baseline strength, and selected candidate polymorphisms on maximal strength training (MST) adaptations. METHODS: A total of 49 subjects (22 men and 27 women) aged 20-76 years, divided into five age groups, completed an 8 weeks MST intervention. Each MST session consisted of 4 sets with 4 repetitions at ∼85-90% of one-repetition maximum (1RM) intensity in leg-press, three times per week. 1RM was tested pre and post the intervention and blood samples were drawn to genotype candidate polymorphisms ACE I/D (rs1799752), ACTN3 R577X (rs1815739), and PPARGC1A Gly482Ser (rs8192678). RESULTS: All age groups increased leg-press 1RM (p < 0.01), with a mean improvement of 24.2 ± 14.0%. There were no differences in improvements between the five age groups or between male and female participants, and there were no non-responders. Baseline strength status did not correlate with 1RM improvements. PPARGC1A rs8192678 T allele carriers had a 15% higher age- and gender corrected baseline 1RM than the CC genotype (p < 0.05). C allele carriers improved 1RM (%) by 34.2% more than homozygotes for the T allele (p < 0.05). CONCLUSION: To the best of our knowledge, this is the first study to report improvement in leg-press maximal strength regardless of gender, baseline strength status in all age groups. The present study is also first to demonstrate an association between the PPARGC1A rs8192678 and maximal strength and its trainability in a moderately trained cohort. MST may be beneficial for good health and performance of all healthy individuals.

Factors Influencing Running Velocity at Lactate Threshold in Male and Female Runners at Different Levels of Performance.

BACKGROUND: The primary aim was to examine the relationship between lactate threshold (LT) expressed as percentage of maximal oxygen uptake (VO2max) and running velocity at LT (LTV). A secondary aim was to investigate to what extent VO2max, oxygen cost of running (CR), and maximal aerobic speed (MAS) determined LTV. A third aim was to investigate potential differences in LT and LTV between elite, national and recreational runners, as well as possible gender differences regarding VO2max, CR, LT, and LTV. METHODS: Seventy-five competitive runners (37 males and 38 females) with an average VO2max of 63.0 ± 9.3 mL⋅kg-1⋅min-1, and an average LTV of 13.6 ± 2.3 km⋅h-1 were tested for VO2max, LT, LTV, MAS, and CR. RESULTS: Lactate threshold did not correlate with LTV. With an r - value of 0.95 (p < 0.001) and a standard error of estimate of 4.0%, the product of MAS and individual LT determined 90% of LTV, outside a range of ±0.27 km⋅h-1. LTV increased with higher performance level. However, LT did not differ between elite, national and recreational runners. Female runners had 2.5% higher LT, 8% lower LTV, and 21% lower VO2max, but 9% better CR than male runners. CONCLUSION: Lactate threshold did not correlate with LTV. The product of MAS and LT correlated strongly with LTV. There were no differences between elite, national and recreational runners regarding LT, but female runners had higher LT than the male runners. Female runners at the same relative performance level had lower LTV and VO2max, but better CR than male runners.

High-intensity aerobic interval training improves aerobic fitness and HbA1c among persons diagnosed with type 2 diabetes.

PURPOSE: It remains to be established how high-intensity aerobic interval training (HAIT) affects risk factors associated with type 2 diabetes (TD2). This study investigated effects of HAIT on maximal oxygen uptake (VO2max), glycated Hemoglobin type A1C (HbA1c), insulin resistance (IR), fat oxidation (FatOx), body weight (BW), percent body fat (%BF), lactate threshold (LT), blood pressure (BP), and blood lipid profile (BLP) among persons with T2D. Results were compared to the effects after a moderate-intensity training (MIT) program. METHODS: Thirty-eight individuals with T2D completed 12 weeks of supervised training. HAIT consisted of 4 × 4 min of walking or running uphill at 85-95% of maximal heart rate, and MIT consisted of continuous walking at 70-75% of maximal heart rate. RESULTS: A 21% increase in VO2max (from 25.6 to 30.9 ml kg-1 min-1, p < 0.001), and a reduction in HbA1c by -0.58% points (from 7.78 to 7.20%, p < 0.001) was found in HAIT. BW and body mass index (BMI) was reduced by 1.9% (p < 0.01). There was a tendency towards an improved FatOx at 60% VO2max (14%, p = 0.065). These improvements were significant different from MIT. Both HAIT and MIT increased velocity at LT, and reduced %BF, waist circumference, hip circumference, and BP, with no significant differences between the two groups. Correlations were found between change in VO2max and change in HbA1c when the two intervention groups were combined (R = -0.52, p < 0.01). CONCLUSION: HAIT is an effective exercise strategy to improve aerobic fitness and reduce risk factors associated with T2D.

The Effect of Age on the V˙O2max Response to High-Intensity Interval Training.

PURPOSE: High-intensity interval training (HIIT) is documented to yield effective improvements in the cardiovascular system and be an excellent strategy for healthy aging. However, it is not determined how age may affect the training response of key components of aerobic endurance. METHODS: We recruited 72 males (mean ± SD, weight = 84.9 ± 12.9 kg, height = 180.4 ± 5.8 cm) and 22 females (weight = 76.0 ± 17.2 kg, height = 171.2 ± 6.7 cm) from 20 to 70+ yr with a training status typical for their age group and divided them into six decade cohorts. The participants followed supervised training with a targeted intensity of 90%-95% of maximal HR (HRmax) three times a week for 8 wk. RESULTS: After HIIT, all age groups increased (P < 0.001-P = 0.004) maximal oxygen consumption (V˙O2max) with 0.39 ± 0.20 (20-29 yr), 0.28 ± 0.21 (30-39 yr), 0.36 ± 0.08 (40-49 yr), 0.34 ± 0.27 (50-59 yr), 0.33 ± 0.23 (60-69 yr), and 0.34 ± 0.14 (70+ yr) L·min, respectively. These 9%-13% improvements were not significantly different between the age groups. In contrast to age, the percentage improvements after HIIT were inversely associated with baseline training status (r = 0.66, P < 0.001). HRmax was not altered within the respective age cohorts, but the two oldest cohorts exhibited a tendency (P = 0.07) to increase HRmax in contrast to a training-induced decrease in the younger cohorts. CONCLUSION: In healthy individuals with an aerobic capacity typical for what is observed in the population, the training response is likely not affected by age in a short-term training intervention but may rather be affected by the initial training status. These findings imply that individuals across age all have a great potential for cardiovascular improvements, and that HIIT may be used as an excellent strategy for healthy aging.

Day to day variability in fat oxidation and the effect after only 1 day of change in diet composition.

Indirect calorimetry is a common and noninvasive method to estimate rate of fat oxidation (FatOx) during exercise, and test-retest reliability should be considered when interpreting results. Diet also has an impact on FatOx. The aim of the present study was to investigate day to day variations in FatOx during moderate exercise given the same diet and 2 different isoenergetic diets. Nine healthy, moderately-trained females participated in the study. They performed 1 maximal oxygen uptake test and 4 FatOx tests. Habitual diets were recorded and repeated to assess day to day variability in FatOx. FatOx was also measured after 1 day of fat-rich (26.8% carbohydrates (CHO), 23.2% protein, 47.1% fat) and 1 day of CHO-rich diet (62.6% CHO, 20.1% protein, 12.4% fat). The reliability test revealed no differences in FatOx, respiratory exchange ratio (RER), oxygen uptake, carbon dioxide production, heart rate, blood lactate concentration, or blood glucose between the 2 habitual diet days. FatOx decreased after the CHO-rich diet compared with the habitual day 2 (from 0.42 ± 0.15 to 0.29 ± 0.13 g·min(-1), p < 0.05). No difference was found in FatOx between fat-rich diet and the 2 habitual diet days. FatOx was 31% lower (from 0.42 ± 0.14 to 0.29 ± 0.13 g·min(-1), p < 0.01) after the CHO-rich diet compared with the fat-rich diet. Using RER data to measure FatOx is a reliable method as long as the diet is strictly controlled. However, even a 1-day change in macronutrient composition will likely affect the FatOx results.

Percent utilization of VO2 max at 5-km competition velocity does not determine time performance at 5 km among elite distance runners.

The present study investigated to what extent maximum oxygen uptake (VO2 max) and fractional utilization (%VO2 max) in 5-km competition speed correlate with 5-km performance times among elite long distance runners. Eight elite long distance runners with 5-km performance times of 15.10 minutes ( +/- 32 seconds) were tested for VO2 max during an incremental protocol and for %VO2 max during an 8-minute treadmill test at the velocity representing their 5-km seasonal best performance time. There was no correlation between fractional utilization and 5-km performance. The study showed no significant difference between VO2 max obtained during an incremental VO2 max test and %VO2 max when running for 8 minutes at the runner's individual 5-km competition speed. The 5-km time was related to the runner's VO2 max even in a homogenous high-level performance group. In conclusion, the present study found no relationship between fractional utilization and 5-km performance time. Training aiming to increase %VO2 max may thus be of little or no importance in performance enhancement for competitions lasting up to approximately 20 minutes.

Maximal strength training improves running economy in distance runners.

PURPOSE: The present study investigated the effect of maximal strength training on running economy (RE) at 70% of maximal oxygen consumption (V[spacing dot above]O2max) and time to exhaustion at maximal aerobic speed (MAS). Responses in one repetition maximum (1RM) and rate of force development (RFD) in half-squats, maximal oxygen consumption, RE, and time to exhaustion at MAS were examined. METHODS: Seventeen well-trained (nine male and eight female) runners were randomly assigned into either an intervention or a control group. The intervention group (four males and four females) performed half-squats, four sets of four repetitions maximum, three times per week for 8 wk, as a supplement to their normal endurance training. The control group continued their normal endurance training during the same period. RESULTS: The intervention manifested significant improvements in 1RM (33.2%), RFD (26.0%), RE (5.0%), and time to exhaustion at MAS (21.3%). No changes were found in V[spacing dot above]O2max or body weight. The control group exhibited no changes from pre to post values in any of the parameters. CONCLUSION: Maximal strength training for 8 wk improved RE and increased time to exhaustion at MAS among well-trained, long-distance runners, without change in maximal oxygen uptake or body weight.