High doses of vitamin C plus E reduce strength training-induced improvements in areal bone mineral density in elderly men.

PURPOSE: Resistance training is beneficial for maintaining bone mass. We aimed to investigate the skeletal effects of high doses of antioxidants [vitamin C + E (α-tocopherol)] supplementation during 12-week supervised strength training in healthy, elderly men METHODS: Design: double-blinded randomized placebo-controlled study. Participants followed a supervised, undulating periodic exercise program with weekly adjusted load: 3 sessions/week and 3-15 repetitions maximum (RM) sets/exercise. The control group (CG, n = 17, 67 ± 5 years) received placebo and the antioxidant group (AO, n = 16, 70 ± 7 years) 1000 mg vitamin C + 235 mg vitamin E, daily. Areal bone mineral density (aBMD) at whole body, lumbar spine (L1-L4), total hip, and femoral neck were measured by dual energy X-ray absorptiometry and muscle strength by 1RM. Serum analyses of bone-related factors and adipokines were performed. RESULTS: In the CG, total hip aBMD increased by 1.0% (CI: 0.3-1.7) versus pretest and lumbar spine aBMD increased by 0.9% (CI: -0.2 to 2.0) compared to the AO. In the CG, there was an increase in serum concentrations of insulin-like growth factor 1 [+27.3% (CI: -0.3 to 54.9)] and leptin [+31.2% (CI: 9.8-52.6)) versus pretest, and a decrease in sclerostin [-9.9% (CI: 4.4-15.3)] versus pretest and versus AO. Serum bone formation markers P1NP and osteocalcin increased in both groups, while the bone resorption marker CTX-1 remained unchanged. CONCLUSION: High doses of antioxidant supplementations may constrain the favorable skeletal benefits of 12 weeks of resistance exercise in healthy elderly men.

Effect of Omega-3 and Vitamins E + C Supplements on the Concentration of Serum B-Vitamins and Plasma Redox Aminothiol Antioxidant Status in Elderly Men after Strength Training for Three Months.

BACKGROUND: Data on redox plasma aminothiol status in individuals on strength training are very limited. Therefore, we studied the effect of omega-3 and vitamins E + C supplementation on the concentration of B-vitamins and redox aminothiol status in elderly men after strength training for 3 months. METHODS: Healthy men, age 60 ± 6 (mean ± SD) were randomly divided into 3 groups: group I received placebo (n = 17), group II consumed omega-3 (700 mg, n = 17), and group III consumed vitamins E + C (235 mg +1 g, n = 16) daily for 3 months. All participants completed a strength training program for the same period. RESULTS: The concentration of serum vitamin B12 decreased and the concentration of serum folate increased in group I after the intervention (p = 0.01, p = 0.009). The concentration of plasma 5-pyridoxal phosphate decreased in groups II and III (p = 0.03 and p = 0.01), whereas the concentration of serum uric acid decreased only in group II (p = 0.02). We detected an increase in the concentration of reduced form of aminothiols in all groups (p < 0.001). The red/ox plasma aminothiol status was significantly changed in all groups after the intervention (p < 0.05). CONCLUSION: Omega-3 and vitamins E + C supplementation affect the concentrations of serum B-vitamins and redox plasma aminothiol status in healthy elderly men on strength training.

Mental Toughness Moderates Social Loafing in Cycle Time-Trial Performance.

PURPOSE: The purpose of this study was to determine if mental toughness moderated the occurrence of social loafing in cycle time-trial performance. METHOD: Twenty-seven men (Mage = 17.7 years, SD = 0.6) completed the Sport Mental Toughness Questionnaire prior to completing a 1-min cycling trial under 2 conditions: once with individual performance identified, and once in a group with individual performance not identified. Using a median split of the mental toughness index, participants were divided into high and low mental toughness groups. Cycling distance was compared using a 2 (trial) × 2 (high-low mental toughness) analysis of variance. We hypothesized that mentally tough participants would perform equally well under both conditions (i.e., no indication of social loafing) compared with low mentally tough participants, who would perform less well when their individual performance was not identifiable (i.e., demonstrating the anticipated social loafing effect). RESULTS: The high mental toughness group demonstrated consistent performance across both conditions, while the low mental toughness group reduced their effort in the non-individually identifiable team condition. CONCLUSIONS: The results confirm that (a) clearly identifying individual effort/performance is an important situational variable that may impact team performance and (b) higher perceived mental toughness has the ability to negate the tendency to loaf.

The impact of rest duration on work intensity and RPE during interval training.

PURPOSE: To investigate the effect of rest duration on self-selected intensity, physiological responses, and RPE during a standardized, high-intensity interval training prescription. SUBJECTS: Nine well-trained male runners (VO(2max) 71 +/- 4 mL.kg(-1).min(-1)) performed three treadmill interval training sessions running at constant 5% incline. Six 4-min work bouts with either 1-, 2-, or 4-min recovery periods were performed in each session. Sessions were prescribed as "high-intensity" workouts with the goal being to achieve the highest possible average running speed for the work intervals. Subjects regulated their work and rest intensity based on these instructions. In a fourth interval session, subjects self-selected recovery time in response to a fixed intensity. RESULTS: Running velocity increased slightly (14.7 +/- 0.7 vs 14.4 +/- 0.8 km.h(-1), P = 0.02) when rest increased from 1 to 2 min, but showed no further increase with a 4-min rest (14.7 +/- 0.6 km.h(-1). Work VO(2) was slightly higher with a 2-min rest duration compared with 1 and 4 min (66.2 +/- 4.2 vs 65.1 +/- 4.2 and 64.9 +/- 4.7 mL.kg(-1).min(-1), P < 0.05). Peak blood lactate was similar (6.2 +/- 2.6, 6.8 +/- 2.9, 6.2 +/- 2.6 mmol.L(-1)) across conditions, whereas peak RPE was slightly lower during the 4-min rest condition (17.1 +/- 1.3, 17.7 +/- 1.5, 16.8 +/- 1.5, P < 0.05). With self-selected recovery time and no knowledge of elapsed time, the average rest duration was 118 +/- 23 s. CONCLUSIONS: Under self-paced conditions, varying rest duration in a range of 1 to 4 min had limited impact on performance during repeated 4-min high-intensity exercise bouts. Approximately 120 s of active recovery may provide an appropriate balance between intracellular restitution and maintenance of high VO(2) on-kinetics.

Rethinking the role of fat oxidation: substrate utilisation during high-intensity interval training in well-trained and recreationally trained runners.

BACKGROUND: Although carbohydrate is the predominant fuel source supporting high-intensity exercise workloads, the role of fat oxidation, and the degree to which it may be altered by training status, is less certain. METHODS: We compared substrate oxidation rates, using indirect calorimetry, during a high-intensity interval training (HIT) session in well-trained (WT) and recreationally trained (RT) runners. Following preliminary testing, 9 WT (VO2max 71±5 mL/min/kg) and 9 RT (VO2max 55±5 mL/min/kg) male runners performed a self-paced HIT sequence consisting of six, 4 min work bouts separated by 2 min recovery periods on a motorised treadmill set at a 5% gradient. RESULTS: WT and RT runners performed the HIT session with the same perceived effort (rating of perceived exertion (RPE) =18.3±0.7 vs 18.2±1.1, respectively), blood lactate (6.4±2.1 vs 6.2±2.5 mmol/L) and estimated carbohydrate oxidation rates (4.2±0.29 vs 4.4±0.45 g/min; effect size (ES) 90% confidence limits (CL)=-0.19±0.85). Fat oxidation (0.64±0.13 vs 0.22±0.16 g/min for WT and RT, respectively) accounted for 33±6% of the total energy expenditure in WT vs 16±6% in RT most likely very large difference in fat oxidation (ES 90% CL=1.74±0.83) runners. Higher rates of fat oxidation had a very large correlation with VO2max (r=0.86; 90% CI (0.7 to 0.94). CONCLUSIONS: Despite similar RPE, blood lactate and carbohydrate oxidation rates, the better performance by the WT group was explained by their nearly threefold higher rates of fat oxidation at high intensity.

Validation of a pre-coded food diary used among 60-80 year old men: comparison of self-reported energy intake with objectively recorded energy expenditure.

OBJECTIVE: To validate energy intake (EI) estimated from a pre-coded food diary (PFD) against energy expenditure (EE) measured with a valid physical activity monitor (SenseWear Pro3 Armband) and to evaluate whether misreporting was associated with overweight/obesity in a group of elderly men. METHODS: Forty-seven healthy Norwegian men, 60-80 years old, completed the study. As this study was part of a larger intervention study, cross-sectional data were collected at both baseline and post-test. Participants recorded their food intake for four consecutive days using food diaries and wore SenseWear Pro3 Armband (SWA) during the same period. Only participants with complete data sets at both baseline and post-test were included in the study. RESULTS: The group average EI was 17% lower at baseline and 18% lower at post-test compared to measured EE. Mean difference from Bland-Altman plot for EI and EE was -1.5 MJ/day (±1.96 SD: -7.0, 4.0 MJ/day) at baseline and -1.6 MJ/day (-6.6, 3.4 MJ/day) at post-test. The intraclass correlation coefficient (ICC) was 0.30 (95% CI: 0.02, 0.54, p = 0.018) at baseline and 0.34 (0.06, 0.57, p = 0.009) at post-test. Higher values of underreporting was shown among overweight/obese compared to normal weight participants at both baseline and post-test (p≤ 0.001), respectively. CONCLUSIONS: The results indicate that the PFD could be a useful tool for estimating energy intake in normal weight elderly men. On the other hand, the PFD seems to be less suitable for estimating energy intake in overweight/obese elderly men.

Quantifying training intensity distribution in a group of Norwegian professional soccer players.

PURPOSE: This study was designed to quantify the daily distribution of training intensity in a group of professional soccer players in Norway based on three different methods of training intensity quantification. METHODS: Fifteen male athletes (age, 24 ± 5 y) performed treadmill test to exhaustion to determine heart rate and VO2 corresponding to ventilatory thresholds (VT1, VT2), maximal oxygen consumption (VO2max) and maximal heart rate. VT1 and VT2 were used to delineate three intensity zones based on heart rate. During a 4 wk period in the preseason (N = 15), and two separate weeks late in the season (N = 11), all endurance and on-ball training sessions (preseason: N = 378, season: N= 78) were quantified using continuous heart rate registration and session rating of perceived exertion (sRPE). Three different methods were used to quantify the intensity distribution: time in zone, session goal and sRPE. RESULTS: Intensity distributions across all sessions were similar when based on session goal or by sRPE. However, intensity distribution based on heart rate cut-offs from standardized testing was significantly different (time in zone). CONCLUSIONS: Our findings suggest that quantifying training intensity by using heart rate based total time in zone is not valid for describing the effective training intensity in soccer. The results also suggest that the daily training intensity distribution in this representative group of high level Norwegian soccer players is organized after a pattern where about the same numbers of training sessions are performed in low lactate, lactate threshold, and high intensity training zones.