Key pointsr Recent studies have indicated that antioxidant supplementation may blunt adaptations to exercise, such as mitochondrial biogenesis induced by endurance training. However, studies in humans are sparse and results are conflicting.r Isolated vitamin C and E supplements are widely used, and unravelling the interference of these vitamins in cellular and physiological adaptations to exercise is of interest to those who exercise for health purposes and to athletes.r Our results show that vitamin C and E supplements blunted the endurance training-induced increase of mitochondrial proteins (COX4), which is important for improving muscular endurance.r Training-induced increases inV O 2 max and running performance were not detectably affected by the supplementation.r The present study contributes to understanding of how antioxidants may interfere with adaptations to exercise in humans, and the results indicate that high dosages of vitamins C and E should be used with caution.Abstract In this double-blind, randomised, controlled trial, we investigated the effects of vitamin C and E supplementation on endurance training adaptations in humans. Fifty-four young men and women were randomly allocated to receive either 1000 mg of vitamin C and 235 mg of vitamin E or a placebo daily for 11 weeks. During supplementation, the participants completed an endurance training programme consisting of three to four sessions per week (primarily of running), divided into high-intensity interval sessions [4-6 × 4-6 min; >90% of maximal heart rate (HR max )] and steady state continuous sessions (30-60 min; 70-90% of HR max ). Maximal oxygen uptake (V O 2 max ), submaximal running and a 20 m shuttle run test were assessed and blood samples and muscle biopsies were collected, before and after the intervention. Participants in the vitamin C and E group increased theirV O 2 max (mean ± S.D.: 8 ± 5%) and performance in the 20 m shuttle test (10 ± 11%) to the same degree as those in the placebo group (mean ± S.D.: 8 ± 5% and 14 ± 17%, respectively). However, the mitochondrial marker cytochrome c oxidase subunit IV (COX4) and cytosolic peroxisome proliferator-activated receptor-γ coactivator 1 α (PGC-1α) increased in the m. vastus lateralis in the placebo group by 59 ± 97% and 19 ± 51%, respectively, but not in the vitamin C and E group (COX4: −13 ± 54%; PGC-1α: −13 ± 29%; P ࣘ 0.03, between groups). Furthermore, mRNA levels of CDC42 and mitogen-activated protein kinase 1 (MAPK1) in the trained muscle were lower in the vitamin C and E group than in the placebo group (P ࣘ 0.05). Daily vitamin C and E supplementation attenuated increases in markers of mitochondrial biogenesis following endurance training. However, no clear interactions were detected for improvements inV O 2 max and running performance. Consequently, vitamin C and E supplementation hampered cellular adaptations in the exercised muscles, and although this did not translate to the performance tests applied in this study, we advocate caution when considering antioxidant supplemen...

The purpose of this study was to compare the effects of combined strength and plyometric training with strength training alone on power related measurements in professional soccer players. Subjects in the intervention team were randomly divided into two groups. Group ST (n = 6) performed heavy strength training twice a week during seven weeks in addition to 6-8 soccer sessions a week. Group ST+P (n = 8) performed a plyometric training program in addition to the same training as the ST group. The control (C) group (n = 7) performed 6-8 soccer sessions a week. Pre and post tests were 1RM half squat, counter movement jump (CMJ), squat jump (SJ), 4-bound test (4BT), peak power in half squat with 20kg, 35kg, and 50 kg (PP 20 , PP 35 , PP 50 , respectively), sprint acceleration, peak sprint velocity and total time 40m sprint. There were no significant difference between the ST+P group and ST group, thus we pooled the groups into one intervention group. The intervention group significantly improved in all measurements except CMJ, while the C group only showed significant improvements in PP 20 . There was significant difference in relative improvement between the intervention group and C group in 1RM half squat, 4BT, and SJ. However, significant difference between groups was not observed in PP 20 , and PP 35 , sprint acceleration, peak sprinting velocity and total time on 40m sprint. The results suggest that there is no significant performance enhancing effects of combining strength and plyometric training in professional soccer players concurrently performing 6-8 soccer sessions a week compared to strength training alone. However, heavy strength training leads to significant gains in strength and power related measurements in professional soccer players.

This file was dowloaded from the institutional repository Brage NIH -brage.bibsys.no/nih Rønnestad, B. R., Hansen, E. A., Raastad T. (2010). Effect of heavy strength training on thigh muscle cross-sectional area performance determinants and performance in well-trained cyclists. ] and mean power output in the 40-min all-out trial were improved in E+S (p<0.05). For E, only performance in the 40-min all-out trial tended to improve (p=0.057).The two groups showed similar increases in VO 2max (p<0.05). In conclusion, adding strength training to usual endurance training improved determinants of cycling performance as well as performance in well-trained cyclists. Of particular note is that the added strength training increased thigh muscle CSA without causing an increase in body mass.

Here we report on the effect of combining endurance training with heavy or explosive strength training on endurance performance in endurance-trained runners and cyclists. Running economy is improved by performing combined endurance training with either heavy or explosive strength training. However, heavy strength training is recommended for improving cycling economy. Equivocal findings exist regarding the effects on power output or velocity at the lactate threshold. Concurrent endurance and heavy strength training can increase running speed and power output at VO2max (Vmax and Wmax, respectively) or time to exhaustion at Vmax and Wmax. Combining endurance training with either explosive or heavy strength training can improve running performance, while there is most compelling evidence of an additive effect on cycling performance when heavy strength training is used. It is suggested that the improved endurance performance may relate to delayed activation of less efficient type II fibers, improved neuromuscular efficiency, conversion of fast-twitch type IIX fibers into more fatigue-resistant type IIA fibers, or improved musculo-tendinous stiffness.

To investigate the effect of supplementing high-volume endurance training with heavy strength training on muscle adaptations and physical performance in elite cross country skiers. Eleven male (18-26 years) and eight female (18-27 years) were assigned to either a strength group (STR) (n=9) or a control group (CON) (n=10). STR performed strength training twice a week for 12 weeks in addition to their normal endurance training. STR improved 1 repetition maximum (RM) for seated pull-down and half squat (19 ± 2% and 12 ± 2%, respectively), while no change was observed in CON. Cross-sectional area (CSA) increased in m. triceps brachii for both STR and CON, while there was no change in the m. quadriceps CSA. VO(2max) during skate-rollerskiing increased in STR (7 ± 1%), while VO(2max) during running was unchanged. No change was observed in energy consumption during rollerskiing at submaximal intensities. Double-poling performance improved more for STR than for CON. Both groups showed a similar improvement in rollerski time-trial performance. In conclusion, 12 weeks of supplemental heavy strength training improved the strength in leg and upper body muscles, but had little effect on the muscle CSA in thigh muscles. The supplemental strength training improved both VO(2max) during skate-rollerskiing and double-poling performance.