Effects of fat loss and low energy availability on the serum cardiometabolic profile of physique athletes.

Low energy availability (LEA) is a health concern for athletes, although it may paradoxically lead to improved cardiometabolic health in the general population. We investigated the associations between LEA, body composition, and serum cardiometabolic profile in 23 physique athletes (DIET) and 21 controls (CONT) during a 5-month pre-competition diet (MID), followed by 1 week of increased energy availability (COMP) and a 5-month weight regain period (POST). Quantification of 250 serum metabolome variables was conducted by NMR spectroscopy, body composition by dual-energy x-ray absorptiometry, dietary intake by food diaries, and exercise levels by training logs. Body fat percentage decreased from 19.5 ± 7.0% to 8.3 ± 5.3% (p < 0.001) in DIET through increased exercise levels and decreased energy intake, while CONT maintained those constant. In MID, DIET had increased (FDR < 0.01) HDL cholesterol, HDL particle size and number, and decreased (FDR < 0.05) VLDL lipids, serum triglycerides, and low-grade inflammation (glycoprotein acetyls) compared to baseline and CONT. The changes were associated with reduced android fat mass (-78 ± 13%) and energy intake (-28 ± 10%). In COMP, most of the metabolic changes found in MID persisted, except for altered triglycerides in all lipoprotein classes. After weight regain in POST, serum metabolome, body composition, energy intake, and exercise levels had reverted to baseline levels. In conclusion, fat loss and LEA may have beneficial yet transient effects on the serum cardiometabolic profile of lean individuals. Especially the HDL lipidome and lipoprotein triglycerides offer potential novel biomarkers for detecting LEA in athletes.

Sprint mechanics evaluation using inertial sensor-based technology: A laboratory validation study.

Advances in micro-electromechanical systems have turned magnetic inertial measurement units (MIMUs) into a suitable tool for vertical jumping biomechanical evaluation. Thus, this study aimed to determine whether appropriate reliability and agreement reports could also be obtained when analyzing 20-m sprint mechanics. Four bouts of 20-m sprints were evaluated to determine whether the data provided by a MIMU placed at the lumbar spine could reliably assess sprint mechanics and to examine the validity of the MIMU sensor compared to force plate recordings. Maximal power (P0 ), force (F0 ), and velocity (V0 ), as well as other mechanical determinants of sprint performance associated with the force-velocity, power-velocity, and ratio of forces-velocity, such as applied horizontal force loss (Sfv ) and decrease in ratio of forces (Drf ), were calculated and compared between instrumentations. Extremely large-to-very large correlation levels between MIMU sensor-based sprint mechanics variables and force plate recordings were obtained (mean±SD, force plate vs MIMU; V0, 8.61±0.85 vs 8.42±0.69; F0 , 383±110 vs 391±103; P0 , 873±246 vs 799±241; Sfv, -44.6±12.7 vs -46.2±10.7), ranging from 0.88 to 0.94, except for Drf, which showed weak-to-moderate correlation level (r=.45; -6.32±1.08 vs -5.76±0.68). Step-averaged force values measured with both systems were highly correlated (r=.88), with a regression slope close to the identity (1.01). Bland and Altman graphical representation showed a no random distribution of measured force values. Finally, very large-to-extremely large retest correlation coefficients were found for the intertrial reliability of MIMU measurements of sprint performance variables (r value ranging from .72 to .96). Therefore, MIMUs showed appropriate validity and reliability values for 20-m sprint performance variables.

Resistance training induced increase in muscle fiber size in young and older men.

Muscle strength and mass decline in sedentary individuals with aging. The present study investigated the effects of both age and 21 weeks of progressive hypertrophic resistance training (RT) on skeletal muscle size and strength, and on myostatin and myogenin mRNA expression in 21 previously untrained young men (26.0 ± 4.3 years) and 18 older men (61.2 ± 4.1 years) and age-matched controls. Vastus lateralis muscle biopsies were taken before and after RT. Type I and type II muscle fiber cross-sectional areas increased more in young men than in older men after RT (P < 0.05). Concentric leg extension increased (P < 0.05) more after 10.5 weeks in young men compared to older men, but after 21 weeks no statistical differences existed. The daily energy and protein intake were greater (P < 0.001) in young subjects. Both myostatin and myogenin mRNA expression increased in older when compared with young men after RT (P < 0.05). In conclusion, after RT, muscle fiber size increased less in older compared to young men. This was associated with lower protein and energy intake and increases in myostatin gene expression in older when compared to young men.

Molecular signaling in muscle is affected by the specificity of resistance exercise protocol.

Mammalian target of rapamycin and mitogen-activated protein kinase (MAPK) signaling pathways have been highlighted as important for muscle adaptations and thus, they may distinguish adaptations to different exercises. Typically, resistance exercise designed for muscle hypertrophy has moderate intensity (60-80% of one repetition maximum, 1 RM) while one prioritizing maximal strength with minor hypertrophy has a higher intensity (≥90% of 1 RM). Eight untrained men (28.4 ± 3.7 years) conducted two different bilateral leg press exercise protocols: hypertrophic (5 × 10 RM) and pure maximal strength (15 × 1 RM) in a counterbalanced, cross-over design with 1 week between exercises. Vastus lateralis muscle biopsies were taken before and 0.5 h after resistance exercise, or in six controls (26.5 ± 3.6 years) who rested. The phosphorylation of p70S6K (Thr(421) /Ser(424) ), rpS6 (Ser(240/244) and Ser(235/236) ) and MAPK p38 as increased (∼2-16 fold) after both exercise protocols. However, the phosphorylation of MAPK Erk1/2 and p70S6K at Thr(389) increased only after 5 × 10 RM. The increase in the phosphorylation of p70S6K (Thr(421) /Ser(424) ), rpS6 (Ser(235/236) ) and Erk1/2 were higher after 5 × 10 RM (P<0.05). No changes were seen in controls. In conclusion, MAPK signaling is greater after hypertrophic than maximal strength exercise protocol. This may mediate adaptations specific to these different types of training regimens.

Acute neuromuscular and hormonal responses during contrast loading: effect of 11 weeks of contrast training.

The purpose of this study was to assess (1) acute neuromuscular and endocrine responses during a contrast loading protocol and (2) how these acute responses are possibly influenced by 11 weeks of contrast training. Contrast loading tests consisting of 4 sets of 80% 1 RM back squat and 4 sets of squat jump (SJ) were performed before and after training. Bilateral isometric leg extension (LE) assessed the impact of loading on isometric variables pre-, mid-, and post-loading. Potentiated SJ performance was observed in set 2 (4.6%, P<0.05), before training only. Greater indications of fatigue were observed in SJ, isometric force, and vastus lateralis (VL) activation after training (P<0.05). Training-induced improvements in SJ height, 80% 1 RM squat load, and maximum isometric LE force were observed (12%, 10%, and 7.7%, P<0.05). In conclusion, potentiated SJ performance occurred during a typical contrast loading protocol before the training period. However, potentiated SJ performance may alter through training, and therefore, the responsiveness of the individual should be periodically monitored and training protocols updated when necessary.

Strength, [corrected] endurance or combined training elicit diverse skeletal muscle myosin heavy chain isoform proportion but unaltered androgen receptor concentration in older men.

We investigated whether the myosin heavy chain (MyHC) proportion and androgen receptor (AR) concentration in skeletal muscle differ following 21 weeks of strength, endurance and combined training in untrained older men. Strength (S) and endurance (E) groups trained twice per week and combined (S+E) group trained four times per week (two strength and two endurance). Muscle biopsies were obtained before and after the training period from m. vastus lateralis (VL) and AR mRNA and protein concentration and MyHC proportion were determined. 1RM increased during the training period in S, S+E and E but the changes were greater in S and S+E than in E. Statistically significant increases were observed only in S and S+E in maximal isometric force as well as in VL thickness. VO (2max) increased significantly only in E. MyHCIIa proportion increased in S, while MyHCIIa proportion decreased and MyHCI increased (p<0.05) in E. No statistically significant changes were observed in serum testosterone and in AR mRNA or protein concentrations. The present results indicate that 21 weeks of strength, endurance or combined training changed MyHC proportion according to the training method but did not have an effect on AR mRNA or protein expression in skeletal muscle at rest.

Active recovery shows favorable IGF-I and IGF binding protein responses following heavy resistance exercise compared to passive recovery.

IGF-I and IGFBPs have important physiological modulatory effects and this study sought to examine the influence of active vs. passive recovery following a heavy resistance exercise on IGF-I and IGF binding protein (IGFBP) recovery responses. It was hypothesized that increased IGF-I and decreased inhibitory IGFBPs during active recovery may be reflective of cascades promoting physiological recovery. 18 untrained men ((AR n = 7, PR n = 11), age: 26 ±â€¯4 years, height: 174 ±â€¯8 cm, body mass: 75 ±â€¯13 kg) performed either a protocol-specific 10 × 10 × 30% 1RM active (AR) or passive recovery (PR) session following a heavy resistance exercise session performed on a leg press device (10 × 10 1RM). Maximal isometric force production (MVC) and IGF- and IGFBPs were measured pre, post, 1-hr post, and next morning. A significantly greater relative response in IGF-I was observed in AR than in PR at post recovery and next morning (p < .01 and statistical trend, respectively) while absolute concentrations of IGFBP-1 at next morning were significantly higher in PR than AR (p < .05), and relative IGFBP-1 response from control to next morning in PR was significantly greater than in AR (p < .001). IGFBP-1 may be inhibitory to IGF-I biological action, thus the lower concentration of IGFBP-1 after AR may be considered favorable in terms of recovery due to its positive relationship with glucose metabolism and maintaining metabolic homeostasis. These results suggest that some of the benefits of an active recovery bout may be mediated by favorable IGF-I system responses (increased IGF-I and decreased IGFBP-1) in the hormonal milieu that may assist facilitating the cascade of physiological recovery processes following acute heavy resistance loading exercise.

Substantial fat mass loss reduces low-grade inflammation and induces positive alteration in cardiometabolic factors in normal-weight individuals.

The accumulation of fat, especially in visceral sites, is a significant risk factor for several chronic diseases with altered cardiometabolic homeostasis. We studied how intensive long-term weight loss and subsequent weight regain affect physiological changes, by longitudinally interrogating the lipid metabolism and white blood cell transcriptomic markers in healthy, normal-weight individuals. The current study examined 42 healthy, young (age: 27.5 ± 4.0 years), normal-weight (body mass index, BMI: 23.4 ± 1.7 kg/m2) female athletes, of which 25 belong to the weight loss and regain group (diet group), and 17 to the control group. Participants were evaluated, and fasting blood samples were drawn at three time points: at baseline (PRE); at the end of the weight loss period (MID: 21.1 ± 3.1 weeks after PRE); and at the end of the weight regain period (POST: 18.4 ± 2.9 weeks after MID). Following the weight loss period, the diet group experienced a ~73% reduction (~0.69 kg) in visceral fat mass (false discovery rate, FDR < 2.0 × 10-16), accompanied by anti-atherogenic effects on transcriptomic markers, decreased low-grade inflammation (e.g., as α1-acid glycoprotein (FDR = 3.08 × 10-13) and hs-CRP (FDR = 2.44 × 10-3)), and an increase in functionally important anti-atherogenic high-density lipoprotein -associated metabolites (FDR < 0.05). This occurred even though these values were already at favorable levels in these participants, who follow a fitness-lifestyle compared to age- and BMI-matched females from the general population (n = 58). Following the weight regain period, most of the observed beneficial changes in visceral fat mass, and metabolomic and transcriptomic profiles dissipated. Overall, the beneficial anti-atherogenic effects of weight loss can be observed even in previously healthy, normal-weight individuals.

Muscle mass and strength, body composition and dietary intake in master strength athletes vs untrained men of different ages.

AIM: The aim of this study was to compare muscle strength and thickness, body composition and dietary intake between master strength athletes and controls. METHODS: Cross-sectional comparison between: 1) young control men (25.7+/-3.4 y; n=10); 2) middle-aged master athletes (52.1+/-4.7 y; n=9); 3) middle-aged control men (51.9+/-3.1 y; n=11); 4) older master athletes (71.8+/-3.8 y; n=8); and 5) older control men (70.6+/-3.3 y; n=10). Athletes had been strength trained for 22.8+/-14.9 y. Maximal isometric strength of the leg extensors was measured with a leg dynamometer, body composition by skin folds, muscle thickness of the vastus lateralis with an ultrasound scanner and dietary intake by food diaries for 4 days. RESULTS: Athletes had more lean body mass than age-matched controls (P<0.001-0.05) and young controls more than older controls (P<0.01). No group differences were observed in the thickness of vastus lateralis. Athletes showed higher absolute strength and strength per vastus lateralis thickness ratio than all control groups (P<0.01-0.001). Body mass adjusted dietary intake did not differ between the strength trained and control men. Dietary intake did not correlate with strength, muscle thickness and lean body mass. CONCLUSION: The present older men with a long-term history of strength training showed greater muscle strength and strength per muscle thickness ratio than the untrained controls. The data support the usefulness of continuous strength training to preserve muscle strength in older men.

Autophagy is induced by resistance exercise in young men, but unfolded protein response is induced regardless of age.

AIM: Autophagy and unfolded protein response (UPR) appear to be important for skeletal muscle homoeostasis and may be altered by exercise. Our aim was to investigate the effects of resistance exercise and training on indicators of UPR and autophagy in healthy untrained young men (n = 12, 27 ± 4 years) and older men (n = 8, 61 ± 6 years) as well as in resistance-trained individuals (n = 15, 25 ± 5 years). METHODS: Indicators of autophagy and UPR were investigated from the muscle biopsies after a single resistance exercise bout and after 21 weeks of resistance training. RESULTS: Lipidated LC3II as an indicator of autophagosome content increased at 48 hours post-resistance exercise (P < .05) and after a resistance training period (P < .01) in untrained young men but not in older men. Several UPRER markers, typically induced by protein misfolding in endoplasmic reticulum, were increased at 48 hours post-resistance exercise in untrained young and older men (P < .05) but were unaltered after the 21-week resistance training period regardless of age. UPR was unchanged within the first few hours after the resistance exercise bout regardless of the training status. Changes in autophagy and UPRER indicators did not correlate with a resistance training-induced increase in muscle strength and size. CONCLUSION: Autophagosome content is increased by resistance training in young previously untrained men, but this response may be blunted by ageing. However, unfolded protein response is induced by an unaccustomed resistance exercise bout in a delayed manner regardless of age.

Effects of strength and endurance training on antioxidant enzyme gene expression and activity in middle-aged men.

This study was aimed at investigating the effects of a 21-week period of progressive strength or endurance training on peripheral blood mononuclear cells (PBMC) antioxidant enzyme gene expression and activity in healthy middle-aged untrained men. Strength (n=11) and endurance (n=12) training were performed twice a week, including resistance exercises to activate all the main muscle groups or cycle-ergometer pedaling, respectively. mRNA levels of catalase, glutathione peroxidase (GPx), mitochondrial superoxide dismutase (MnSOD) and cytosolic superoxide dismutase (CuZnSOD) were increased after 21 weeks of strength training, while endurance training induced significant changes only in MnSOD and GPx mRNA levels. CuZnSOD protein content was significantly increased only in strength-trained subjects. The program of strength or endurance exercise training had no significant effects on the activity of any of the antioxidant enzymes. In conclusion, in a middle-aged population, 21 weeks of strength or endurance training was a sufficient stimulus to up-regulate mRNA levels of PBMC antioxidant enzymes, the strength training being a more optimal stimulus. However, the discrepancies between enzyme protein and mRNA levels suggest that the present systematic strength or endurance training period had no beneficial effects on enzymatic antioxidant defense mechanisms in previously untrained middle-aged men.

Acute hormonal and neuromuscular responses and recovery to forced vs maximum repetitions multiple resistance exercises.

Acute hormonal and neuromuscular responses and recovery three days after the exercises were examined during the maximum repetitions (MR) and forced repetitions (FR) resistance exercise protocols in 16 male athletes. MR included 4 sets of leg presses, 2 sets of squats and 2 sets of knee extensions (with 12 RM) with a 2-min recovery between the sets and 4 min between the exercises. In FR the initial load was chosen to be higher than in MR so that the subject could not lift 12 repetitions per set by himself. After each set to failure the subject was assisted to perform the remaining repetitions to complete the 12 repetitions per set. Thus the exercise intensity was greater in FR than in MR. Both loading protocols led to the great acute increases (p < 0.05 - 0.001) in serum testosterone, free testosterone, cortisol and GH concentrations. However, the responses in cortisol (p < 0.05) and GH (p < 0.01) were larger in FR than in MR. The decrease of 56.5 % (p < 0.001) in maximal isometric force in FR was greater (p < 0.001) than that of 38.3 % in MR (p < 0.001) and force remained lower (p < 0.01) during the recovery in FR compared to MR. The larger decrease in isometric strength in FR than in MR was also associated with the decreased maximal voluntary EMG of the loaded muscles. The data indicate that the forced repetition exercise system induced greater acute hormonal and neuromuscular responses than a traditional maximum repetition exercise system and therefore it may be used to manipulate acute resistance exercise variables in athletes.