Cardiovascular, muscular, and skeletal adaptations to recreational team handball training: a randomized controlled trial with young adult untrained men.

PURPOSE: The prevalence of lifestyle diseases has escalated, and effective exercise training programmes are warranted. This study tested the hypothesis that regular participation in small-sided team handball training could provide beneficial health effects on cardiovascular, skeletal, and muscular parameters in young adult untrained men. METHOD: Twenty-six untrained 20-30-year-old men were randomly allocated to either a team handball training group (HG; n = 14), which completed 1.9 ± 0.3 training sessions per week over 12 weeks, or an inactive control group (CG; n = 12). Physiological training adaptations were assessed pre- and post interventions by DXA scans, blood samples, muscle biopsies, and physical tests. RESULTS: The average heart rate during training was equivalent to 84 ± 4% of maximal heart rate. Compared to CG, HG displayed significant increases in VO2max (11 ± 6%), proximal femur bone mineral density (2 ± 1%), whole-body bone mineral content (2 ± 1%), intermittent endurance performance (32 ± 16%), incremental treadmill test performance (16 ± 7%) and muscle citrate synthase activity (22 ± 28%) as well as decreases in total fat mass (7 ± 7%) and total fat percentage (6 ± 7%) (all p < 0.05). There were no significant changes in muscle mass, blood pressure, resting heart rate, muscle hydroxyl-acyl-dehydrogenase activity, or blood lipids (all p > 0.05). CONCLUSION: Participation in regular recreational team handball training was associated with positive cardiovascular, skeletal, and muscular adaptations, including increased maximal oxygen uptake, increased muscle enzymatic activity, and improved bone mineralization as well as lower fat percentage. These findings suggest that recreational team handball training may be an effective health-promoting activity for young adult men.

Correction to: Cardiovascular, muscular, and skeletal adaptations to recreational team handball training: a randomized controlled trial with young adult untrained men.

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Effects of long-term football training on the expression profile of genes involved in muscle oxidative metabolism.

We investigated whether long-term recreational football training affects the expression of health-related biochemical and molecular markers in healthy untrained subjects. Five untrained healthy men trained for 1 h 2.4 times/week for 12 weeks and 1.3 times/week for another 52 weeks. Blood samples and a muscle biopsy from the vastus lateralis were collected at T0 (pre intervention) and at T1 (post intervention). Gene expression was measured by RTqPCR on RNA extracted from muscle biopsies. The expression levels of the genes principally involved in energy metabolism (PPARγ, adiponectin, AMPKα1/α2, TFAM, NAMPT, PGC1α and SIRT1) were measured at T0 and T1. Up-regulation of PPARγ (p < 0.0005), AMPKα1 (p < 0.01), AMPKα2 (p < 0.0005) and adiponectin was observed at T1 vs T0. Increases were also found in the expression of TFAM (p < 0.001), NAMPT (p < 0.01), PGC1α (p < 0.01) and SIRT1 (p < 0.01), which are directly or indirectly involved in the glucose and lipid oxidative metabolism. Multiple linear regression analysis revealed that fat percentage was independently associated with NAMPT, PPARγ and adiponectin expression. In conclusion, long-term recreational football training could be a useful tool to improve the expression of muscle molecular biomarkers that are correlated to oxidative metabolism in healthy males.

Physiological response and activity profile in recreational small-sided football: no effect of the number of players.

We examined the effect of the number of players on the activity profile and physiological response to small-sided recreational football games with fixed relative pitch size. Twelve untrained men (age: 33.0 ± 6.4 (± standard deviation) years, fat%: 22.4 ± 6.1%, VO2 max: 43.3 ± 5.2 mL/min/kg) completed three football sessions of 4 times 12 min with 3v3, 5v5, or 7v7 in a randomized order. Pitch sizes were 80 m(2) per player. Activity profile (10 Hz global positioning system), heart rate (HR), and rating of perceived exertion (RPE) were measured, and blood samples were collected before and during games. Average HR was 84.1 ± 3.9, 84.5 ± 5.0, and 82.8 ± 5.1 %HRmax for 3v3, 5v5, and 7v7, respectively, with no difference between game formats. High blood lactate (5.9 ± 2.9, 5.9 ± 2.4, and 5.5 ± 2.9 mmol/L) and plasma NH3 concentrations (124 ± 48, 112 ± 38, and 126 ± 55 µmol/L, respectively) were observed during 3v3, 5v5, and 7v7, respectively, with no difference between formats. Similar total distance (3676 ± 478, 3524 ± 467, and 3577 ± 500 m), high-intensity distance (349 ± 145, 406 ± 134, and 409 ± 165 m), and RPE (4.7 ± 1.6, 4.9 ± 2.1, and 4.6 ± 1.8) were also observed. The number of intense accelerations (500 ± 139 vs 459 ± 143 and 396 ± 144) were higher (P < 0.05) during 3v3 than 5v5 and 7v7. In conclusion, the intensity is high during small-sided recreational football games, with similar physiological responses for 6-14 players when pitch size is adapted, providing further evidence that effective recreational football training is easy to organize.

Street football is a feasible health-enhancing activity for homeless men: biochemical bone marker profile and balance improved.

This case-control study investigated the feasibility of street football as a health-enhancing activity for homeless men, specifically the musculoskeletal effects of 12 weeks of training. Twenty-two homeless men participated in the football group (FG) and 10 served as controls (C). Plasma osteocalcin, TRACP5b, leptin, and postural balance were measured, and whole-body DXA scanning was performed. The attendance rate was 75% (2.2 ± 0.7 sessions per week). During 60 min of training, the total distance covered was 5534 ± 610 m, with 1040 ± 353, 2744 ± 671, and 864 ± 224 m covered by high-intensity, low-intensity, and backwards/sideways running, respectively. In FG, osteocalcin increased by 27% from 20.1 ± 11.1 to 25.6 ± 11.8 ng/mL (P = 0.007). Postural balance increased by 39% (P = 0.004) and 46% (P = 0.006) in right and left leg. Trunk bone mineral density increased by 1.0% from 0.959 ± 0.095 to 0.969 ± 0.090 g/cm(2) (P = 0.02). No effects were observed in C. In conclusion, street football appears to be a feasible training activity with musculoskeletal health benefits for homeless men. The attendance rate and the training intensity were high, and 12 weeks of training resulted in a substantial anabolic response in bone metabolism. Postural balance improved markedly, and the overall risk of falling, and hospitalization due to sudden trauma, could be reduced by street football for homeless men.

Effect of football or strength training on functional ability and physical performance in untrained old men.

The effects of 16 weeks of football or strength training on performance and functional ability were investigated in 26 (68.2 ± 3.2 years) untrained men randomized into a football (FG; n = 9), a strength training (ST; n = 9), or a control group (CO; n = 8). FG and ST trained 1.6 ± 0.1 and 1.5 ± 0.1 times per week, respectively, with higher (P < 0.05) average heart rate (HR) (∼140 vs 100 bpm) and time >90%HRmax (17 vs 0%) in FG than ST, and lower (P < 0.05) peak blood lactate in FG than ST (7.2 ± 0.9 vs 10.5 ± 0.6 mmol/L). After the intervention period (IP), VO2 max (15%; P < 0.001), cycle time to exhaustion (7%; P < 0.05), and Yo-Yo Intermittent Endurance Level 1 performance (43%; P < 0.01) were improved in FG, but unchanged in ST and CO. HR during walking was 12% and 10% lower (P < 0.05) in FG and ST, respectively, after IP. After IP, HR and blood lactate during jogging were 7% (P < 0.05) and 30% lower (P < 0.001) in FG, but unchanged in ST and CO. Sit-to-stand performance was improved (P < 0.01) by 29% in FG and 26% in ST, but not in CO. In conclusion, football and strength training for old men improves functional ability and physiological response to submaximal exercise, while football additionally elevates maximal aerobic fitness and exhaustive exercise performance.

Experimental considerations of acute heat stress assays to quantify coral thermal tolerance.

Understanding the distribution and abundance of heat tolerant corals across seascapes is imperative for predicting responses to climate change and to support novel management actions. Thermal tolerance is variable in corals and intrinsic and extrinsic drivers of tolerance are not well understood. Traditional experimental evaluations of coral heat and bleaching tolerance typically involve ramp-and-hold experiments run across days to weeks within aquarium facilities with limits to colony replication. Field-based acute heat stress assays have emerged as an alternative experimental approach to rapidly quantify heat tolerance in many samples yet the role of key methodological considerations on the stress response measured remains unresolved. Here, we quantify the effects of coral fragment size, sampling time point, and physiological measures on the acute heat stress response in adult corals. The effect of fragment size differed between species (Acropora tenuis and Pocillopora damicornis). Most physiological parameters measured here declined over time (tissue colour, chlorophyll-a and protein content) from the onset of heating, with the exception of maximum photosynthetic efficiency (Fv/Fm) which was surprisingly stable over this time scale. Based on our experiments, we identified photosynthetic efficiency, tissue colour change, and host-specific assays such as catalase activity as key physiological measures for rapid quantification of thermal tolerance. We recommend that future applications of acute heat stress assays include larger fragments (> 9 cm2) where possible and sample between 10 and 24 h after the end of heat stress. A validated high-throughput experimental approach combined with cost-effective genomic and physiological measurements underpins the development of markers and maps of heat tolerance across seascapes and ocean warming scenarios.

Performance enhancements and muscular adaptations of a 16-week recreational football intervention for untrained women.

The present study investigated the performance effects and physiological adaptations over 16 weeks of recreational football training and continuous running for healthy untrained premenopausal women in comparison with an inactive control group [Football group (FG): n=21; running group (RG): n=18; CO: n=14]. Two weekly 1-h training sessions were performed in FG and RG. After 4 and 16 weeks of training VO(2max) was elevated (P<0.05) by 7% and 15%, respectively, in FG, and by 6% and 10%, respectively, in RG. After 16 weeks, Yo-Yo intermittent endurance level 2 performance was 33% and 19% better (P<0.05) for FG and 29% and 21% better (P<0.05) for RG than after 4 and 0 weeks, respectively. Peak sprinting speed was 12% higher (21.0 +/- 0.6 vs 18.8 +/- 0.7 km/h; P<0.05) for FG after the training period, whereas no difference was observed for RG. After 4 weeks citrate synthase (CS) and 3-hydroxyacyl-CoA dehydrogenase (HAD) activity was 9% and 8%, respectively, higher (P<0.05) than before training in FG with no further changes during the last 12 weeks. In RG, CS increased (P<0.05) by 12% after 4 weeks and no significant increase was observed for HAD. In FG, the number of capillaries per fiber was 18% higher (P<0.05) after 16 weeks (2.44 +/- 0.15 vs 2.07 +/- 0.05 cap/fiber), with no significant difference for RG. No differences were observed between 0 and 16 weeks for CO. In conclusion, recreational women's football leads to significant increases in VO(2max), performance and muscular adaptations throughout a 16-week training period. Thus, football can be used as an activity to elevate the physical capacity of untrained women.

Activity profile and physiological response to football training for untrained males and females, elderly and youngsters: influence of the number of players.

The present study examined the activity profile, heart rate and metabolic response of small-sided football games for untrained males (UM, n=26) and females (UF, n=21) and investigated the influence of the number of players (UM: 1v1, 3v3, 7v7; UF: 2v2, 4v4 and 7v7). Moreover, heart rate response to small-sided games was studied for children aged 9 and 12 years (C9+C12, n=75), as well as homeless (HM, n=15), middle-aged (MM, n=9) and elderly (EM, n=11) men. During 7v7, muscle glycogen decreased more for UM than UF (28 +/- 6 vs 11 +/- 5%; P<0.05) and lactate increased more (18.4 +/- 3.6 vs 10.8 +/- 2.1 mmol kg(-1) d.w.; P<0.05). For UM, glycogen decreased in all fiber types and blood lactate, glucose and plasma FFA was elevated (P<0.05). The mean heart rate (HR(mean)) and time >90% of HR(max) ranged from 147 +/- 4 (EM) to 162 +/- 2 (UM) b.p.m. and 10.8 +/- 1.5 (UF) to 47.8 +/- 5.8% (EM). Time >90% of HR(max) (UM: 16-17%; UF: 8-13%) and time spent with high speed running (4.1-5.1%) was similar for training with 2-14 players, but more high-intensity runs were performed with few players (UM 1v1: 140 +/- 17; UM 7v7: 97 +/- 5; P<0.05): Small-sided games were shown to elucidate high heart rates for all player groups, independently of age, sex, social background and number of players, and a high number of intense actions both for men and women. Thus, small-sided football games appear to have the potential to create physiological adaptations and improve performance with regular training for a variety of study groups.

Positive performance and health effects of a football training program over 12 weeks can be maintained over a 1-year period with reduced training frequency.

We examined whether improvements in the performance and health profile of an intensive 12-week football intervention could be maintained with a reduced training frequency. Seventeen healthy untrained males completed the study. Ten subjects trained 2.4 times/week for 12 weeks and another 52 weeks with 1.3 sessions/week [football group (FG)] and seven subjects acted as controls [control group (CG)]. For FG, fat mass (3.2 kg) and systolic blood pressure (8 mmHg) were lower (P<0.05) after 64 than 0 weeks, and VO(2max) (8%) and Yo-Yo intermittent endurance level 2 test performance (49%) were higher (P<0.05), with no difference between 64 and 12 weeks. After 64 weeks, quadriceps muscle mass (11%), mean fiber area (10%) and citrate synthase activity (18%) were higher (P<0.05) than those at 0 weeks. Leg bone mass (3.5%) and density (2.0%) were higher (P<0.05) after 64 than 0 weeks, but not different between 12 and 0 weeks. Plantar jump force (17-18%), 30-m sprinting velocity (1.3-3.0%) and muscle glycogen concentration (19-21%) were higher (P<0.05) and blood lactate during submaximal exercise was lower (27-72%, P<0.05) after 64 than after 12 and 0 weeks. The above-mentioned variables were unaltered for CG. In conclusion, positive adaptations in cardiovascular fitness obtained over 12 weeks of regular recreational football training can be maintained over a 1-year period with a reduced training frequency, with further development in musculo-skeletal fitness.

Recreational soccer is an effective health-promoting activity for untrained men.

To examine the effects of regular participation in recreational soccer on health profile, 36 healthy untrained Danish men aged 20-43 years were randomised into a soccer group (SO; n = 13), a running group (RU; n = 12) and a control group (CO; n = 11). Training was performed for 1 h two or three times per week for 12 weeks; at an average heart rate of 82% (SEM 2%) and 82% (1%) of HR(max) for SO and RU, respectively. During the 12 week period, maximal oxygen uptake increased (p<0.05) by 13% (3%) and 8% (3%) in SO and RU, respectively. In SO, systolic and diastolic blood pressure were reduced (p<0.05) from 130 (2) to 122 (2) mm Hg and from 77 (2) to 72 (2) mm Hg, respectively, after 12 weeks, with similar decreases observed for RU. After the 12 weeks of training, fat mass was 3.0% (2.7 (0.6) kg) and 1.8% (1.8 (0.4) kg) lower (p<0.05) for SO and RU, respectively. Only SO had an increase in lean body mass (1.7 (0.4) kg, p<0.05), an increase in lower extremity bone mass (41 (8) g, p<0.05), a decrease in LDL-cholesterol (2.7 (0.2) to 2.3 (0.2) mmol/l; p<0.05) and an increase (p<0.05) in fat oxidation during running at 9.5 km/h. The number of capillaries per muscle fibre was 23% (4%) and 16% (7%) higher (p<0.05) in SO and RU, respectively, after 12 weeks. No changes in any of the measured variables were observed for CO. In conclusion, participation in regular recreational soccer training, organised as small-sided drills, has significant beneficial effects on health profile and physical capacity for untrained men, and in some aspects it is superior to frequent moderate-intensity running.

Microdialysis ethanol removal reflects probe recovery rather than local blood flow in skeletal muscle.

The present study compared the microdialysis ethanol outflow-inflow technique for estimating blood flow (BF) in skeletal muscle of humans with measurements by Doppler ultrasound of femoral artery inflow to the limb (BFFA). The microdialysis probes were inserted in the vastus lateralis muscle and perfused with a Ringer acetate solution containing ethanol, [2-3H]adenosine (Ado), and D-[14C(U)]glucose. BFFA at rest increased from 0.16 +/- 0.02 to 1.80 +/- 0.26 and 4.86 +/- 0.53 l/min with femoral artery infusion of Ado (AdoFA,i) at 125 and 1,000 microg . min-1 . l-1 thigh volume (low dose and high dose, respectively; P < 0.05) and to 3.79 +/- 0.37 and 6.13 +/- 0.65 l/min during one-legged, dynamic, thigh muscle exercise without and with high AdoFA,i, respectively (P < 0.05). The ethanol outflow-to-inflow ratio (38.3 +/- 2.3%) and the probe recoveries (PR) for [2-3H]Ado (35.4 +/- 1.6%) and for D-[14C(U)]glucose (15.9 +/- 1.1%) did not change with AdoFA,i at rest (P = not significant). During exercise without and with AdoFA,i, the ethanol outflow-to-inflow ratio decreased (P < 0.05) to a similar level of 17.5 +/- 3.4 and 20.6 +/- 3.2%, respectively (P = not significant), respectively, while the PR increased (P < 0.05) to a similar level (P = not significant) of 55.8 +/- 2.8 and 61.2 +/- 2. 5% for [2-3H]Ado and to 42.8 +/- 3.9 and 45.2 +/- 5.1% for D-[14C(U)]glucose. Whereas the ethanol outflow-to-inflow ratio and PR correlated inversely and positively, respectively, to the changes in BF during muscular contractions, neither of the ratio nor PR correlated to the AdoFA,i-induced BF increase. Thus the ethanol outflow-to-inflow ratio does not represent skeletal muscle BF but rather contraction-induced changes in molecular transport in the interstitium or over the microdialysis membrane.

Rapid detection, identification, and enumeration of Pseudomonas aeruginosa in bottled water using peptide nucleic acid probes.

A new chemiluminescent in situ hybridization (CISH) method that provides simultaneous detection, identification, and enumeration of Pseudomonas aeruginosa in bottled water within 1 working day has been developed. Individual micro-colonies of P. aeruginosa were detected directly on membrane filters following 5 h of growth by use of soybean peroxidase-labeled peptide nucleic acid (PNA) probes targeted to a species-specific sequence in P. aeruginosa rRNA. Within each micro-colony, reaction of the peroxidase with a chemiluminescent substrate generated light that was subsequently captured by film or with a digital camera system. Each spot of light represented one micro-colony of P. aeruginosa. Sensitivity and specificity for the identification of P. aeruginosa were 100% as determined by testing 28 P. aeruginosa strains and 17 other bacterial species that included closely related Pseudomonas species. Furthermore, the number of micro-colonies of P. aeruginosa represented by light spots correlated with counts of visible colonies following sustained growth. We conclude that PNA CISH speeds up traditional membrane filtration techniques and adds the specificity of PNA probe technology to generate fast and definitive results.

Identification of indicator microorganisms using a standardized PNA FISH method.

A standardized fluorescent in situ hybridization (FISH) method using Peptide Nucleic Acid (PNA) probes for analysis of gram-negative and gram-positive bacteria, as well as yeast, has been developed. Fluorescently labeled PNA probes targeting specific rRNA sequences of Escherichia coli, Pseudomonas aeruginosa, Staphyloccocus aureus, Salmonella were designed, as well as PNA probes targeting eubacteria and eucarya. These PNA probes were evaluated by PNA FISH using 27 bacterial and 1 yeast species, representing both phylogenetically closely related species, as well as species important to both clinical and industrial settings. The S. aureus and P. aeruginosa PNA probes did not cross react with any of the organisms tested, whereas the E. coli PNA probe, as expected from sequence data, also detected Shigella species. The Salmonella PNA probe reacted with all of the 13 Salmonella strains, representing the 7 subspecies of Salmonella, however, it is also complementary to a few other bacterial species. The eubacteria- and eucarya-specific PNA probes detected all bacterial species and one yeast species, respectively. The general applicability of the PNA FISH method made simultaneous identification of multiple species, both gram-negative and gram-positive, in a mixed population an attractive possibility never accomplished using DNA probes. Four color images using differently labeled PNA probes showed simultaneous identification of E. coli, P. aeruginosa, S. aureus and Salmonella, thereby demonstrating the potential of multiplex FISH for various diagnostic applications within both clinical and industrial microbiology.

Interstitial K(+) in human skeletal muscle during and after dynamic graded exercise determined by microdialysis.

Interstitial K(+) concentrations were measured during one-legged knee-extensor exercise by use of microdialysis with probes inserted in the vastus lateralis muscle of the subjects. K(+) in the dialysate was measured either by flame photometry or a K(+)-sensitive electrode placed in the perfusion outlet. The correction for fractional K(+) recovery was based on the assumption of identical fractional thallium loss. The interstitial K(+) was 4. 19 +/- 0.09 mM at rest and increased to 6.17 +/- 0.19, 7.48 +/- 1.18, and 9.04 +/- 0.74 mM at 10, 30, and 50 W exercise, respectively. The individual probes demonstrated large variations in interstitial K(+), and values >10 mM were obtained. The observed interstitial K(+) was markedly higher than previously found for venous K(+) concentrations at similar work intensities. The present data support a potential role for interstitial K(+) in regulation of blood flow and development of fatigue.

Exercise-induced translocation of Na(+)-K(+) pump subunits to the plasma membrane in human skeletal muscle.

Six human subjects performed one-legged knee extensor exercise (90 +/- 4 W) until fatigue (exercise time 4.6 +/- 0.8 min). Needle biopsies were obtained from vastus lateralis muscle before and immediately after exercise. Production of giant sarcolemmal vesicles from the biopsy material was used as a membrane purification procedure, and Na(+)-K(+) pump alpha- and beta-subunits were quantified by Western blotting. Exercise significantly increased (P < 0.05) the vesicular membrane content of the alpha(2)-, total alpha-, and beta(1)-subunits by 70 +/- 29, 35 +/- 10, and 26 +/- 5%, respectively. The membrane content of alpha(1) was not changed by exercise, and the densities of subunits in muscle homogenates were unchanged. The ratio of vesicular to crude muscle homogenate content of the alpha(2)-, total alpha-, and beta(1)-subunits was elevated during exercise by 67 +/- 33 (P < 0.05), 23 +/- 6 (P < 0.05), and 40 +/- 14% (P = 0.06), respectively. It is concluded that translocation of subunits is an important mechanism involved in the short time upregulation of the Na(+)-K(+) pumps in association with human muscle activity.