Correction to: Force-velocity profiling of sprinting athletes: single-run vs. multiple-run methods.

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Force-velocity profiling of sprinting athletes: single-run vs. multiple-run methods.

PURPOSE: This study explored the agreement between a single-run and a multiple-run method for force-velocity (Fv) profiling of sprinting athletes; we evaluated both absolute values and changes over time caused by sprint training. METHODS: Seventeen female handball players (23 ± 3 years, 177 ± 7 cm, 73 ± 6 kg) performed 30 m un-resisted and resisted sprints (50, 80 and 110 N resistance) before and after an 8-week sprint training intervention. Two approaches were used to calculate theoretical maximal velocity (v0), horizontal force (F0), power (Pmax), and the force-velocity slope (SFv): (1) the single-run method, based on inverse dynamics applied to the centre-of-mass movement, was calculated from anthropometric and sprint split time data; and (2) the multiple-run method, where peak velocity from un-resisted and resisted sprints were plotted against the horizontal resistances. RESULTS: Trivial differences in v0 (0.7%) were observed between the two calculation methods. Corresponding differences for F0, Pmax and SFv were 16.4, 15.6 and 17.6%, respectively (most likely; very large effect size). F0 showed poor agreement between the methods (r = 0.26 and 0.16 before and after the intervention). No substantial correlation between the changes (from pre- to post-training tests) in SFV calculated with the single-run and the multiple-run methods were observed (r = 0.03) [corrected]. CONCLUSIONS: This study revealed poor agreement between the Fv relationships of the investigated calculation methods. In practice, both methods may have a purpose, but the single-run and the multiple-run methods appear to measure somewhat different sprint properties and cannot be used interchangeably.

Effects of Water Immersion Methods on Postexercise Recovery of Physical and Mental Performance.

Ahokas, EK, Ihalainen, JK, Kyröläinen, H, and Mero, AA. Effects of water immersion methods on postexercise recovery of physical and mental performance. J Strength Cond Res 33(6): 1488-1495, 2019-The aim of this study was to compare the effectiveness of 3 water immersion interventions performed after active recovery compared with active recovery only on physical and mental performance measures and physiological responses. The subjects were physically active men (age 20-35 years, mean ± SD 26 ± 3.7 years). All subjects performed a short-term exercise protocol, including maximal jumps and sprinting. Four different recovery methods (10 minutes) were used in random order: cold water immersion (CWI, 10° C), thermoneutral water immersion (TWI, 24° C), and contrast water therapy (CWT, alternately 10° C and 38° C). All these methods were performed after an active recovery (10-minute bicycle ergometer; heart rate [HR] 120-140 b·min, 60-73% from age-calculated maximum HR), and the fourth method was active recovery (ACT) only. Within 96 hours after exercise bouts, recovery was assessed through a 30-m maximal sprint test, maximal countermovement jump (CMJ), self-perceived muscle soreness and relaxation questionnaires, and blood lactate, creatine kinase, testosterone, cortisol, and catecholamine levels. The self-perceived feeling of relaxation after 60-minute recovery was better (p < 0.05) after CWI and CWT than ACT and TWI. Statistically significant differences were not observed between the recovery methods in any other marker. In the 30-m sprint test, however, slower running time was found in ACT (p < 0.001) and CWT (p = 0.005), and reduced CMJ results (p < 0.05) were found in ACT when the results were compared with baseline values. Based on these findings, it can be concluded that CWI and CWT improve the acute feeling of relaxation that can play a positive role in athletes' performance and well-being.

Low Energy Availability Is Difficult to Assess but Outcomes Have Large Impact on Bone Injury Rates in Elite Distance Athletes.

We aimed to (a) report energy availability (EA), metabolic/reproductive function, bone mineral density, and injury/illness rates in national/world-class female and male distance athletes and (b) investigate the robustness of various diagnostic criteria from the Female Athlete Triad (Triad), Low Energy Availability in Females Questionnaire, and relative energy deficiency in sport (RED-S) tools to identify risks associated with low EA. Athletes were distinguished according to benchmarks of reproductive function (amenorrheic [n = 13] vs. eumenorrheic [n = 22], low [lowest quartile of reference range; n = 10] versus normal testosterone [n = 14]), and EA calculated from 7-day food and training diaries (< or >30 kcal·kg-1 fat-free mass·day-1). Sex hormones (p < .001), triiodothyronine (p < .05), and bone mineral density (females, p < .05) were significantly lower in amenorrheic (37%) and low testosterone (40%; 15.1 ± 3.0 nmol/L) athletes, and bone injuries were ∼4.5-fold more prevalent in amenorrheic (effect size = 0.85, large) and low testosterone (effect size = 0.52, moderate) groups compared with others. Categorization of females and males using Triad or RED-S tools revealed that higher risk groups had significantly lower triiodothyronine (female and male Triad and RED-S: p < .05) and higher number of all-time fractures (male Triad: p < .001; male RED-S and female Triad: p < .01) as well as nonsignificant but markedly (up to 10-fold) higher number of training days lost to bone injuries during the preceding year. Based on the cross-sectional analysis, current reproductive function (questionnaires/blood hormone concentrations) appears to provide a more objective and accurate marker of optimal energy for health than the more error-prone and time-consuming dietary and training estimation of EA. This study also offers novel findings that athlete health is associated with EA indices.

Dietary Microperiodization in Elite Female and Male Runners and Race Walkers During a Block of High Intensity Precompetition Training.

We investigated one week of dietary microperiodization in elite female (n = 23) and male (n = 15) runners and race-walkers by examining the frequency of training sessions and recovery periods conducted with recommended carbohydrate (CHO) and protein availability. Food and training diaries were recorded in relation to HARD (intense or >90min sessions; KEY) versus RECOVERY days (other-than KEY sessions; EASY). The targets for amount and timing of CHO and protein around KEY sessions were based on current nutrition recommendations. Relative daily energy and CHO intake was significantly (p < .05) higher in males (224 ± 26 kJ/kg/d, 7.3 ± 1.4 g/kg/d CHO) than females (204 ± 29 kJ/kg/d, 6.2 ± 1.1 g/kg/d CHO) on HARD days. However, when adjusted for training volume (km), there was no sex-based difference in CHO intake daily (HARD: 0.42 ± 0.14 vs 0.39 ± 0.15 g/kg/km). Females appeared to periodize energy and protein intake with greater intakes on HARD training days (204 ± 29 vs 187 ± 35 kJ/kg/d, p = .004; 2.0 ± 0.3 vs 1.9 ± 0.3 g/kg/d protein, p = .013), while males did not periodize intakes. Females showed a pattern of periodization of postexercise CHO for KEY vs EASY (0.9 ± 0.4 vs 0.5 ± 0.3 g/kg; p < .05) while males had higher intakes but only modest periodization (1.3 ± 0.9 vs 1.0 ± 0.4; p = .32). There was only modest evidence from female athletes of systematic microperiodization of eating patterns to meet contemporary sports nutrition guidelines. While this pattern of periodization was absent in males, in general they consumed more energy and CHO daily and around training sessions compared with females. Elite endurance athletes do not seem to systematically follow the most recent sports nutrition guidelines of periodized nutrition.

A Mismatch Between Athlete Practice and Current Sports Nutrition Guidelines Among Elite Female and Male Middle- and Long-Distance Athletes.

Contemporary nutrition guidelines promote a variety of periodized and time-sensitive recommendations, but current information regarding the knowledge and practice of these strategies among world-class athletes is limited. The aim of this study was to investigate this theme by implementing a questionnaire on dietary periodization practices in national/international level female (n = 27) and male (n = 21) middle- and long-distance runners/race-walkers. The questionnaire aimed to gain information on between and within-day dietary choices, as well as timing of pre- and posttraining meals and practices of training with low or high carbohydrate (CHO) availability. Data are shown as percentage (%) of all athletes, with differences in responses between subgroups (sex or event) shown as Chi-square x2 when p < .05. Nearly two-thirds of all athletes reported that they aim to eat more food on, or after, hard training days. Most athletes said they focus on adequate fueling (96%) and adequate CHO and protein (PRO) recovery (87%) around key sessions. Twenty-six percent of athletes (11% of middle vs 42% of long-distance athletes [x2 (1, n = 46) = 4.308, p = .038, phi = 0.3])) reported to undertake training in the fasted state, while 11% said they periodically restrict CHO intake, with 30% ingesting CHO during training sessions. Our findings show that elite endurance athletes appear to execute pre- and post-key session nutrition recovery recommendations. However, very few athletes deliberately undertake some contemporary dietary periodization approaches, such as training in the fasted state or periodically restricting CHO intake. This study suggests mismatches between athlete practice and current and developing sports nutrition guidelines.

Body composition and power performance improved after weight reduction in male athletes without hampering hormonal balance.

The aim of this study was to investigate the effects of a 4-week weight reduction period with high protein and reduced carbohydrate intake on body composition, explosive power, speed, serum hormones, and acid-base balance in male track and field jumpers and sprinters. Eight participants were assigned to a high weight reduction group (HWR; energy restriction 750 kcal·d) and 7 to a low weight reduction group (LWR; energy restriction 300 kcal·d). Energy and carbohydrate intake decreased significantly (p ≤ 0.05) only in HWR by 740 ± 330 kcal·d and 130 ± 29 g·d, respectively. Furthermore, total body mass and fat mass decreased (p ≤ 0.05) only in HWR by 2.2 ± 1.0 kg and 1.7 ± 1.6 kg, respectively. Fat-free mass (FFM), serum testosterone, cortisol, and sex hormone-binding globulin did not change significantly. Ca ion and pH decreased (p ≤ 0.05) only in HWR (3.1 ± 2.8% and 0.8 ± 0.8%, respectively), whereas (Equation is included in full-text article.)declined (p ≤ 0.05) in both groups by 19.3 ± 6.2% in HWR and by 13.1 ± 8.5% in LWR. The countermovement jump and 20-m sprint time improved consistently (p ≤ 0.05) only in HWR, by 2.6 ± 2.5 cm and 0.04 ± 0.04 seconds, respectively. Finally, athletes with a fat percentage of 10% or more at the baseline were able to preserve FFM. In conclusion, altered acid-base balance but improved weight-bearing power performance was observed without negative consequences on serum hormones and FFM after a 4-week weight reduction of 0.5 kg·wk achieved by reduced carbohydrate but maintained high protein intake.

Acute leukocyte, cytokine and adipocytokine responses to maximal and hypertrophic resistance exercise bouts.

The purpose of this study was to examine the acute immune response (circulating levels of leukocytes, cytokines and adipocytokines) to maximal resistance (MAX, 15 × 1RM) and hypertrophic resistance (HYP, 5 × 10RM) exercise bouts. Twelve healthy men (age = 28.2 ± 3.5 years, weight = 78.6 ± 10.4 kg, height 178.8 ± 5.0 cm, fat percentage = 16.5 ± 3.5 %) participated in the study. Blood was sampled before, immediately after and 15 and 30 min after exercise. Leukocytes (WBC) significantly increased immediately after HYP (p < 0.01), whereas in MAX, increases in WBC became significant after 30 min (p < 0.05). Lymphocytes increased only after HYP (p < 0.001), while MAX induced lymphopenia during recovery (p < 0.01). Monocyte chemoattractant protein-1 (MCP-1) decreased (p < 0.05) and interleukin-1 receptor antagonist (IL-1ra) increased after HYP, which were not observed after MAX. Adipsin and resistin decreased after both exercise bouts (p < 0.05), which suggest that heavy resistance exercise is at least transiently beneficial for adipocytokine profile. Immediate mechanical stress seemed similar as no differences in myoglobin response were observed. The higher magnitude of metabolic demand reflected in higher lactate response in HYP could be the reason for the significantly high responses in WBC, IL-1ra and decrease in MCP-1.

Effects of carbohydrate ingestion on acute leukocyte, cortisol, and interleukin-6 response in high-intensity long-distance running.

The purpose of this study was to investigate the effect of ingestion of fluids with different carbohydrate concentrations (0, 1.5, and 7%) on the acute immune stress responses after high-intensity long-distance running. Continuous 18- to 20-km run was performed at 75% of maximal oxygen uptake with carbohydrate supplementation (CHO7%, 7% carbohydrate solution) and low-carbohydrate supplementation (lowCHO1.5%, 1.5% carbohydrate solution) in a randomized, double-blind, placebo (PLA) controlled design. Seven recreational runners (4 men and 3 women) completed all 3 trials. Blood was collected at baseline (PRE) and immediately after the run (POST). The running task induced significant (p ≤ 0.05) increases in leukocyte (white blood cells), neutrophil, and interleukin-6 (IL-6) counts in every trial. There was a significant (p ≤ 0.05) increase in cortisol with PLA and lowCHO1.5% but not with CHO7%. Increase in total leukocyte and neutrophil concentration was significantly lower with CHO7% compared with PLA (p ≤ 0.05). Postexercise IL-6 levels were significantly elevated when compared with baseline in all conditions (p ≤ 0.05). Interleukin-6 (IL-6) concentrations did not differ significantly between trials. LowCHO1.5% sport drink did not significantly differ from PLA in measured variables, which indicated that the amount and rate of carbohydrate ingestion (15 g, 10 g·h) in low-carbohydrate sport drink was not enough to significantly protect from the stress induced by high-intensity long-distance running, whereas the ingestion of CHO7% (45 g·h) blunted the significant cortisol response and significantly decreased the leukocyte response.

Recovery after heavy resistance exercise and skeletal muscle androgen receptor and insulin-like growth factor-I isoform expression in strength trained men.

The effects of heavy resistance exercise on skeletal muscle androgen receptor (AR) protein concentration and mRNAs of AR, insulin-like growth factor-I (IGF)-IEa, and mechano growth factor (MGF) expression were examined from biopsies of vastus lateralis (VL) muscle before and 48 hours after heavy resistance exercise (5 × 10 repetition maximum [RM] leg press and 4 × 10RM squats) in 8 adult strength trained men. The present exercise induced an acute decrease in maximal isometric force and increased serum total testosterone (T) and free testosterone (FT) concentrations. During 2 recovery days, maximal isometric force and subjective perception of physical fitness remained significantly lowered, whereas serum creatine kinase activity, subjective muscle soreness, and muscle swelling (i.e., thickness of VL by ultrasound) were significantly increased compared to pre-exercise values. Subjective perception of physical fitness was followed up to 7 days, and by 6 days postexercise, it was elevated above the pre-exercise level. Basal T and FT concentrations remained unaltered after the exercise. No statistically significant changes were observed in AR protein or mRNA expression, but IGF-IEa (p < 0.05) and MGF (p < 0.05) mRNA expression were increased compared to pre-exercise levels. These findings indicate that IGF-IEa and MGF responses may be related to acute regenerative processes in muscle because of exercise and may contribute to muscular adaptation to resistance exercise. Subjective perception of physical fitness suggests that recovery over a pre-exercise level of the present type of heavy resistance exercise can take approximately 6 days.

Body Composition, Energy Availability, Training, and Menstrual Status in Female Runners.

PURPOSE: To determine body composition, energy availability, training load, and menstrual status in young elite endurance running athletes (ATH) over 1 year, and in a secondary analysis, to investigate how these factors differ between nonrunning controls (CON), and amenorrheic (AME) and eumenorrheic (EUM) ATH. Correlations to injury, illness, and performance were also examined. METHODS: Altogether 13 ATH and 8 CON completed the Low Energy Availability in Females Questionnaire. Anthropometric, energy intake, and peak oxygen uptake assessments were made at 4 time points throughout the year: at baseline post competition season, post general preparation, post specific preparation, and post competition season the following year. Logs of physical activity, menstrual cycle, illness, and injury were kept by all participants. Performance was defined using the highest International Association of Athletics Federations points prior to and after the study. RESULTS: ATH had significantly lower body mass (P < .008), fat percentage (P < .001), and body mass index (P < .027) compared with CON, while energy availability did not differ between ATH and CON. The Low Energy Availability in Females Questionnaire score was higher in ATH than in CON (P < .028), and 8 ATH (vs zero CON) were AME. The AME had significantly more injury days (P < .041) and ran less (P < .046) than EUM, while total annual running distance was positively related to changes in performance in ATH (r < .62, P < .043, n < 11). CONCLUSIONS: More than half of this group of runners was AME, and they were injured more and ran less than their EUM counterparts. Furthermore, only the EUM runners increased their performance over the course of the year.

Panoramic ultrasonography is a valid method to measure changes in skeletal muscle cross-sectional area.

The purpose of this study was to examine the reliability and validity of the "panoramic" brightness mode ultrasonography (US) method to detect training-induced changes in muscle cross-sectional area (CSA) by comparison with results obtained using magnetic resonance imaging (MRI). Out of 27 young male volunteers, 20 subjects were assigned to training group and seven to non-training control group. Muscle CSAs of vastus lateralis were analyzed by MRI and US before and after 21 weeks of either heavy resistance training or control period. Measured by both the US and MRI, the resistance training induced significant increases (~13-14%, P < 0.001) in muscle CSA, whereas no changes were observed in control group. A high repeatability was found between the two consequent US measurements (intraclass correlation coefficient, ICC of 0.997) with standard error of measurement (SEM) of 0.38 cm(2) and smallest detectable difference of 1.1 cm(2). Validity of the US method against MRI in assessing CSA of VL produced ICC of 0.905 and SEM of 0.87 cm(2) with high limits of agreement analyzed by Bland and Altman method. However, the MRI produced systematically (10 +/- 4%, P < 0.01) larger CSA values than the US method. The US showed high agreement against MRI in detecting changes in muscle CSA (ICC of 0.929, SEM of 0.94 cm(2)). The results of this study showed that the panoramic US method provides repeatable measures of a muscle CSA although MRI produced larger absolute CSA values. Moreover, this US method detects training-induced changes in muscle CSA with a comparable degree of precision to MRI.

Resistance exercise with whey protein ingestion affects mTOR signaling pathway and myostatin in men.

Signaling pathways sense local and systemic signals and regulate muscle hypertrophy. The effects of whey protein ingestion on acute and long-term signaling responses of resistance exercise are not well known. Previously untrained young men were randomized into protein (n = 9), placebo (n = 9), and control (n = 11) groups. Vastus lateralis (VL) muscle biopsies were taken before and 1 h and 48 h after a leg press of 5 x 10 repetitions [resistance exercise (RE)] and after 21 wk (2 times per week) of resistance training (RT). Protein (15 g of whey) or nonenergetic placebo was ingested before and after a single RE bout and each RE workout throughout the RT. The protein group increased its body mass and VL muscle thickness (measured by ultrasonography) already at week 10.5 (P < 0.05). At week 21, the protein and placebo groups had similarly increased their myofiber size. No changes were observed in the nonexercised controls. However, the phosphorylation of p70(S6K) and ribosomal protein S6 (rpS6) were increased at 1 h post-RE measured by Western blotting, the former being the greatest with protein ingestion. Mammalian target of rapamycin (mTOR) phosphorylation was increased after the RE bout and RT only in the protein group, whereas the protein ingestion prevented the post-RE decrease in phosphorylated eukaryotic initiation factor 4E binding protein 1 (p-4E-BP1). Akt phosphorylation decreased after RT, whereas no change was observed in phosphorylated eukaryotic elongation factor 2. A post-RE decrease in muscle myostatin protein occurred only in the placebo group. The results indicate that resistance exercise rapidly increases mTOR signaling and may decrease myostatin protein expression in muscle and that whey protein increases and prolongs the mTOR signaling response.

Acute and long-term effects of resistance exercise with or without protein ingestion on muscle hypertrophy and gene expression.

The effects of timed ingestion of high-quality protein before and after resistance exercise are not well known. In this study, young men were randomized to protein (n = 11), placebo (n = 10) and control (n = 10) groups. Muscle cross-sectional area by MRI and muscle forces were analyzed before and after 21 weeks of either heavy resistance training (RT) or control period. Muscle biopsies were taken before, and 1 and 48 h after 5 x 10 repetition leg press exercise (RE) as well as 21 weeks after RT. Protein (15 g of whey both before and after exercise) or non-energetic placebo were provided to subjects in the context of both single RE bout (acute responses) as well as each RE workout twice a week throughout the 21-week-RT. Protein intake increased (P < or = 0.05) RT-induced muscle cross-sectional area enlargement and cell-cycle kinase cdk2 mRNA expression in the vastus lateralis muscle suggesting higher proliferating cell activation response with protein supplementation. Moreover, protein intake seemed to prevent 1 h post-RE decrease in myostatin and myogenin mRNA expression but did not affect activin receptor IIb, p21, FLRG, MAFbx or MyoD expression. In conclusion, protein intake close to resistance exercise workout may alter mRNA expression in a manner advantageous for muscle hypertrophy.

Androgen receptors and testosterone in men--effects of protein ingestion, resistance exercise and fiber type.

The purpose of this study was to examine the impact of protein ingestion on circulating testosterone and muscle androgen receptor (AR) as well as on insulin-like growth factor-I (MGF and IGF-IEa) responses to a resistance exercise (RE) bout in (57-72 year) men. Protein (15 g whey) (n=9) or placebo (n=9) was consumed before and after a RE bout (5 sets of 10 repetition maximums), and vastus lateralis muscle biopsies were taken pre, 1 and 48 h post-RE. The protein ingestion blunted the RE-induced increase in serum free and total testosterone while the RE bout significantly increased muscle AR mRNA levels in older men (P<0.05). However, protein ingestion did not significantly affect AR mRNA or protein expression, or MGF and IGF-IEa mRNA expression at 1 and 48 h post-RE. Immunohistochemical staining of muscle cross-sections was done with antibodies specific to AR and MyHC I and II and showed that there seems to be within or near the type-I muscle fibers a greater staining of ARs than within or near the type-II fibres. In conclusion, the protein ingestion hinders RE-induced increase in serum testosterone in older men but may not significantly affect muscle AR, MGF or IGF-IEa gene expression. Furthermore, the present study shows that even older men are able to increase muscle AR mRNA expression in response to a RE bout.

The effects of whey protein on myostatin and cell cycle-related gene expression responses to a single heavy resistance exercise bout in trained older men.

Myostatin decreases muscle mass and this is accomplished, in part, by inhibiting muscle satellite cell proliferation and differentiation by regulating the expression of cell cycle-related proteins (e.g. p21 and cdk2) and myogenic regulatory factors (e.g. myogenin and MyoD). The purpose of this investigation was to determine whether protein ingestion before and after a resistance exercise (RE) bout affects myostatin and cell cycle-related gene expression. Strength-trained middle-aged to older men were divided into a protein group (61.4 +/- 4.3 years, n = 9) or a placebo group (62.1 +/- 4.2 years, n = 9). Muscle biopsies from the vastus lateralis muscle were taken at rest and 1 and 48 h after a 5 x 10 repetition leg press RE bout. Protein (15 g whey) or non-caloric placebo was taken immediately before and after the RE bout. mRNA expression levels of myostatin and related genes (AcvrIIb, FLRG, p21, p27, cdk2, myogenin and MyoD) were determined by Taqman probe-based real-time RT-PCR and normalized to GAPDH mRNA. Myostatin mRNA decreased after a RE bout, but only in the placebo group (P < or = 0.05). Conversely, myostatin-binding protein FLRG and cell-cycle kinase cdk2 mRNA increased only in the protein group (P < or = 0.05). p21 mRNA was increased at 1 h post-RE in placebo (P < or = 0.05) and tended to be increased in the protein group (P = 0.08). Myostatin, its binding protein and cell cycle-related gene expressions are affected by single RE bout and these responses are further modified by whey protein intake. Therefore, controlling nutrition intake is important when studying gene expression responses to exercise.

Impact of Energy Availability, Health, and Sex on Hemoglobin-Mass Responses Following Live-High-Train-High Altitude Training in Elite Female and Male Distance Athletes.

PURPOSE: The authors investigated the effects of sex, energy availability (EA), and health status on the change in hemoglobin mass (ΔHbmass) in elite endurance athletes over ∼3-4 wk of live-high-train-high altitude training in Flagstaff, AZ (2135 m; n = 27 women; n = 21 men; 27% 2016 Olympians). METHODS: Precamp and postcamp Hbmass (optimized carbon monoxide rebreathing method) and iron status were measured, EA was estimated via food and training logs, and a Low Energy Availability in Females Questionnaire (LEAFQ) and a general injury/illness questionnaire were completed. Hypoxic exposure (h) was calculated with low (<500 h), moderate (500-600 h), and high (>600 h) groupings. RESULTS: Absolute and relative percentage ΔHbmass was significantly greater in women (6.2% [4.0%], P < .001) than men (3.2% [3.3%], P = .008). %ΔHbmass showed a dose-response with hypoxic exposure (3.1% [3.8%] vs 4.9% [3.8%] vs 6.8% [3.7%], P = .013). Hbmasspre was significantly higher in eumenorrheic vs amenorrheic women (12.2 [1.0] vs 11.3 [0.5] g/kg, P = .004). Although statistically underpowered, %ΔHbmass was significantly less in sick (n = 4, -0.5% [0.4%]) vs healthy (n = 44, 5.4% [3.8%], P < .001) athletes. There were no significant correlations between self-reported iron intake, sex hormones, or EA on Hbmass outcomes. However, there was a trend for a negative correlation between LEAFQ score and %ΔHbmass (r = -.353, P = .07). CONCLUSIONS: The findings confirm the importance of baseline Hbmass and exposure to hypoxia on increases in Hbmass during altitude training, while emphasizing the importance of athlete health and indices of EA on an optimal baseline Hbmass and hematological response to hypoxia.

Inflammation status of healthy young men: initial and specific responses to resistance training.

Our primary aim was to study the effects of a 4-week preparatory resistance-training (RT) period followed by 12 weeks of 2 specific RT protocols (either hypertrophic-strength (HS) or strength-hypertrophy-power training) on inflammation markers and the possible relationship of the changes in abdominal fat and lean mass to the changes in inflammation status. A total of 82 healthy men were included in the study. Maximal concentric leg press strength (1-repetition maximum), total body lean mass, total body and abdominal fat mass, circulating high-sensitivity C-reactive protein, interleukin-6, interleukin-1 receptor antagonist (IL-1ra), monocyte chemoattractant protein 1 (MCP-1), and selected adipocytokines (resistin, adiponectin, and leptin) concentrations were measured before and after 4 (wk4) and 16 weeks (wk16) of RT. After the initial phase of RT, on wk4, abdominal and total fat mass as well as plasma leptin concentrations were significantly reduced (p < 0.05), whereas muscle mass, IL-1ra, resistin, and MCP-1 concentrations were significantly increased (p < 0.05). During specialized training phase, at wk16, only HS led to further reduction in abdominal and total fat mass, resistin, and leptin (p < 0.05), whereas both training modes led to lower MCP-1 concentrations (p < 0.05). Abdominal fat mass and circulating leptin were reduced already after 4 weeks of RT. Simultaneously, circulating MCP-1 and resistin concentrations increased, possibly as markers of muscle adaptation and regeneration. The present findings also suggest that RT with hypertrophic focus is beneficial for further reductions in abdominal fat mass and to decrease circulating inflammatory markers.

Effects of 12-Week Low or Moderate Dietary Acid Intake on Acid-Base Status and Kidney Function at Rest and during Submaximal Cycling.

Prolonged effects of dietary acid intake on acid-base status and kidney function have not yet been studied in an intervention study in healthy subjects. Dietary acid load can be estimated by calculating the potential renal acid load (PRAL) of foods. Effects of low-PRAL and moderate-PRAL diets on acid-base status and kidney function were investigated during a 12-week exercise training period. Healthy, 20-50-year-old men (n = 21) and women (n = 25) participated in the study and were randomly divided into low-PRAL and moderate-PRAL groups. Before (PRE), mid-phase (MID) and after the intervention (POST), the subjects participated in measurement sessions, where a 12-h urine sample and fasting blood samples were collected, and a submaximal cycle ergometer test was performed. Net acid excretion was significantly lower after 12 weeks of the low-PRAL diet as compared to the moderate-PRAL diet, both in men and women. In low-PRAL females, capillary pH and bicarbonate were significantly higher at 75% of VO2max at POST as compared to PRE. Glomerular filtration rate decreased over the study period in moderate-PRAL men and women. The results of the present study suggest that an acidogenic diet and regularly training together may increase the acidic load of the body and start to impair the kidney function in recreationally active subjects.

Postexercise myostatin and activin IIb mRNA levels: effects of strength training.

PURPOSE: Muscle hypertrophy is likely to result from the cumulative effects of repeated bouts of resistance exercise (RE) on postexercise molecular responses. Therefore, we determined muscle growth- and regeneration-related mRNA expression in response to a single RE bout both before and after a strength-training (ST) period. By means of this novel longitudinal setting, we examined whether postexercise gene expression at the transcriptional level is different in the trained and untrained state. METHODS: Eleven untrained healthy older men and 11 controls (age 62.3 +/- 6.3 yr) volunteered as subjects. Muscle biopsies from the vastus lateralis muscle were taken at rest and 1 and 48 h after five sets of 10-repetition leg press RE both before and after 21 wk of supervised ST. RESULTS: Myostatin and myogenin mRNA expression, determined by real-time RT-PCR, increased (P < 0.05) after ST. Conversely, the single RE bout decreased myostatin mRNA after ST, with the decrease showing a negative correlation (r = -0.65, P < 0.05) with the long-term increase in myostatin during ST. Furthermore, RE before ST increased myogenin mRNA (P < 0.05) and tended to increase after ST (P = 0.08). Myostatin receptor activin IIb mRNA levels were decreased at 1 h after RE in the pre-ST condition (P = 0.05) and also tended to decrease in the post-ST condition (P = 0.07). RE-induced downregulation in myostatin mRNA correlated with the ST-induced increase in total body muscle mass (r = -0.82, P = 0.002). CONCLUSIONS: A single bout of RE in older men can downregulate the expression of myostatin receptor activin IIb mRNA. ST influences the response of myostatin to RE, as short-term RE-induced downregulation of myostatin was observed only after ST. The results also indicate that RE-induced alterations in myostatin mRNA expression may have a role in ST-induced muscle hypertrophy.