Intensified training augments cardiac function, but not blood volume, in male youth elite ice hockey team players.

While it is well-established that a period of interval training performed at near maximal effort, such as speed endurance training (SET), enhances intense exercise performance in well-trained individuals, less is known about its effect on cardiac morphology and function as well as blood volume. To investigate this, we subjected 12 Under-20 Danish national team ice hockey players (age 18 ± 1 years, mean ± SD) to 4 weeks of SET, consisting of 6-10 × 20 s skating bouts at maximal effort interspersed by 2 min of recovery conducted three times weekly. This was followed by 4 weeks of regular training (follow-up). We assessed resting cardiac function and dimensions using transthoracic echocardiography and quantified total blood volume with the carbon monoxide rebreathing technique at three time points: before SET, after SET and after the follow-up period. After SET, stroke volume had increased by 10 (2-18) mL (mean (95% CI)), left atrial end-diastolic volume by 10 (3-17) mL, and circumferential strain improved by 0.9%-points (1.7-0.1) (all P < 0.05). At follow-up, circumferential strain and left atrial end-diastolic volume were reverted to baseline levels, while stroke volume remained elevated. Blood volume and morphological parameters for the left ventricle, including mass and end-diastolic volume, did not change during the study. In conclusion, our findings demonstrate that a brief period of SET elicits beneficial central cardiac adaptations in elite ice hockey players independent of changes in blood volume.

15 weeks of soccer training increases left ventricular mass and improves indices of left ventricular diastolic function in previously sedentary, mildly hypertensive, middle-aged women.

PURPOSE: To investigate the impact of soccer training on cardiac adaptations in mildly hypertensive middle-aged women. METHODS: Hypertensive premenopausal women (n = 41; age (mean ± SD): 44 ± 7 years; height: 166 ± 6 cm; weight: 78.6 ± 11.6 kg; body fat: 43.3 ± 5.2%) were randomized to soccer training (SOC, n = 21) or control (CON, n = 20). SOC performed three weekly training sessions for 15 weeks, whereas CON had no training or lifestyle changes during the same period. Cardiac structure and function were assessed by echocardiography pre-intervention and post-intervention. RESULTS: Soccer training increased (P = 0.001) left ventricular mass index by 10% [95% CI 4; 15], while no changes occurred in CON (time × group interaction, P = 0.005). In addition, only SOC demonstrated a within-group increase (P = 0.01) of 8% [95% CI 2; 14] in left ventricular septum diameter. For markers of right ventricular remodelling, a within-group increase (P = 0.02) occurred for tricuspid annulus plane systolic excursion of 8% [95% CI 1; 14] in SOC only. Left atrial diameter index increased (P < 0.001) by 6% [95% CI 3; 10] after SOC, while it was unaffected in CON (time × group interaction, P = 0.02). For makers of diastolic function, SOC demonstrated a within-group increase (P = 0.02) in the average early diastolic mitral annulus velocity of 10% [95% CI 2; 19]. In addition, a reduction (P < 0.001) in mitral valve A velocity of - 19% [95% CI - 29; - 10] was observed following soccer training, which manifested in increased (P < 0.001) mitral valve E/A ratio of 34% [95% CI 16; 53] in SOC. No within-group changes were apparent in CON. CONCLUSION: In sedentary, mildly hypertensive, middle-aged women, 15 weeks of soccer training increases left ventricular mass and left atrial diameter and improves indices of left ventricular diastolic function.

Caffeine Gum Improves Reaction Time but Reduces Composure Versus Placebo During the Extra-Time Period of Simulated Soccer Match-Play in Male Semiprofessional Players.

This study aimed to determine whether caffeine gum influenced perceptual-cognitive and physical performance during the extra-time period of simulated soccer match-play. Semiprofessional male soccer players (n = 12, age: 22 ± 3 years, stature: 1.78 ± 0.06 m, mass: 75 ± 9 kg) performed 120-min soccer-specific exercise on two occasions. In a triple-blind, randomized, crossover design, players chewed caffeinated (200 mg; caffeine) or control (0 mg; placebo) gum for 5 min following 90 min of soccer-specific exercise. Perceptual-cognitive skills (i.e., passing accuracy, reaction time, composure, and adaptability) were assessed using a soccer-specific virtual reality simulator, collected pre- and posttrial. Neuromuscular performance (reactive-strength index, vertical jump height, absolute and relative peak power output, and negative vertical displacement) and sprint performance (15 and 30 m) were measured at pretrial, half-time, 90 min, and posttrial. Caffeine gum attenuated declines in reaction time (pre: 90.8 ± 0.8 AU to post: 90.7 ± 0.8 AU) by a further 4.2% than placebo (pre: 92.1 ± 0.8 AU to post: 88.2 ± 0.8 AU; p < .01). Caffeine gum reduced composure by 4.7% (pre: 69.1 ± 0.8 AU to post: 65.9 ± 0.8 AU) versus placebo (pre: 68.8 ± 0.8 AU to post: 68.3 ± 0.8 AU; p < .01). Caffeine gum did not influence any other variables (p > .05). Where caffeine gum is consumed by players prior to extra-time, reaction time increases but composure may be compromised, and neuromuscular and sprint performance remain unchanged. Future work should assess caffeine gum mixes with substances like L-theanine that promote a relaxed state under stressful conditions.

No net utilization of intramuscular lipid droplets during repeated high-intensity intermittent exercise.

Intramuscular lipids are stored as subsarcolemmal or intramyofibrillar droplets with potential diverse roles in energy metabolism. We examined intramuscular lipid utilization through transmission electron microscopy during repeated high-intensity intermittent exercise, an aspect that is hitherto unexplored. Seventeen moderately to well-trained males underwent three periods (EX1-EX3) of 10 × 45-s high-intensity cycling [∼100%-120% Wattmax (Wmax)] combined with maximal repeated sprints (∼250%-300% Wmax). M. vastus lateralis biopsies were obtained at baseline, after EX1, and EX3. During the complete exercise session, no net decline in either subsarcolemmal or intermyofibrillar lipid volume density occurred. However, a temporal relationship emerged for subsarcolemmal lipids with an ∼11% increase in droplet size after EX1 (P = 0.024), which reverted to baseline levels after EX3 accompanied by an ∼30% reduction in the numerical density of subsarcolemmal lipid droplets compared with both baseline (P = 0.019) and after EX1 (P = 0.018). Baseline distinctions were demonstrated with an approximately twofold higher intermyofibrillar lipid volume in type 1 versus type 2 fibers (P = 0.008), mediated solely by a higher number rather than the size of lipid droplets (P < 0.001). No fiber-type-specific differences were observed in subsarcolemmal lipid volume although type 2 fibers exhibited ∼17% larger droplets (P = 0.034) but a lower numerical density (main effect; P = 0.010) including 3% less droplets at baseline. Collectively, these findings suggest that intramuscular lipids do not serve as an important substrate during high-intensity intermittent exercise; however, the repeated exercise pattern mediated a temporal remodeling of the subsarcolemmal lipid pool. Furthermore, fiber-type- and compartment-specific differences were found at baseline underscoring the heterogeneity in lipid droplet deposition.NEW & NOTEWORTHY Undertaking a severe repeated high-intensity intermittent exercise protocol led to no net decline in neither subsarcolemmal nor intermyofibrillar lipid content in the thigh muscle of young moderately to well-trained participants. However, a temporal remodeling of the subsarcolemmal pool of lipid droplets did occur indicative of potential transient lipid accumulation. Moreover, baseline fiber-type distinctions in subcellular lipid droplet deposition were present underscoring the diversity in lipid droplet storage among fiber types and subcellular regions.

"11 for Health" in the Faroe Islands: Popularity in schoolchildren aged 10-12 and the effect on well-being and health knowledge.

BACKGROUND: We aimed to investigate the popularity of the "11 for Health program for Europe" for 10-12-year-old Faroese children and the effects on well-being and health knowledge. METHODS: We applied a cluster-randomized controlled trial, including a total of 19 school clusters, randomized into intervention schools (IG, n = 12) and control schools (CG, n = 7). A total of 261 children (137 boys and 124 girls) participated. IG completed the 11-week program, consisting of 2 × 45 min weekly sessions with football drills, small-sided games, and health education. CG continued their regular education. Pre- and post-intervention, the participants completed a shortened version of the multidimensional well-being questionnaire KIDSCREEN-27 and a 34-item multiple-choice health knowledge questionnaire. RESULTS: Between-group differences (p < 0.05) were observed in change scores for physical well-being and overall peers and social support in favor of IG compared with CG, as well as for physical well-being in IG girls compared with CG girls. Between-group differences in change score for overall health knowledge (11.8%, p < 0.001, ES: 0.82) were observed in favor of IG, as well as for playing football (8.9%, p = 0.039, ES: 0.24), be active (8.1%, p = 0.017, ES: 0.32), control your weight (18.5%, p < 0.001, ES: 0.52), wash your hands (19.5%, p < 0.001, ES: 0.59), eat a balanced diet (19.3%, p < 0.001, ES: 0.64), get fit (12.1%, p = 0.007, ES: 0.34), and think positive (5.5%, p = 0.039, ES: 0.22). The program was reported as enjoyable with equal moderate-to-high scores for girls (3.68 ± 1.23; ±SD) and boys (3.84 ± 1.17) on a 1-5 Likert Scale. CONCLUSION: The "11 for Health program for Europe" improved physical well-being, peers, and social support and broad-spectrum health knowledge in 10-12-year-old Faroese schoolchildren and was rated popular.

The recovery of muscle function and glycogen levels following game-play in young elite male ice hockey players.

Despite the frequent occurrence of congested game fixtures in elite ice hockey, the postgame recovery pattern has not previously been investigated. The purpose of the present study was therefore to evaluate the acute decrements and subsequent recovery of skeletal muscle glycogen levels, muscle function and repeated-sprint ability following ice hockey game-play. Sixteen male players from the Danish U20 national team completed a training game with muscle biopsies obtained before, postgame and following ~38 h of recovery (day 2). On-ice repeated-sprint ability and muscle function (maximal voluntary isometric [MVIC] and electrically induced low- (20 Hz) and high-frequency (50 Hz) knee-extensor contractions) were assessed at the same time points, as well as ~20 h into recovery (day 1). Muscle glycogen decreased 31% (p < 0.001) postgame and had returned to pregame levels on day 2. MVIC dropped 11%, whereas 50 and 20 Hz torque dropped 21% and 29% postgame, respectively, inducing a 10% reduction in the 20/50 Hz torque ratio indicative of low-frequency force depression (all p < 0.001). While MVIC torque returned to baseline on day 1, 20 and 50 Hz torque remained depressed by 9%-11% (p = 0.010-0.040), hence restoring the pre-exercise 20/50 Hz ratio. Repeated-sprint ability was only marginally reduced by 1% postgame (p = 0.041) and fully recovered on day 1. In conclusion, an elite youth ice hockey game induces substantial reductions in muscle glycogen content and muscle function, but only minor reductions in repeated-sprint ability and with complete recovery of all parameters within 1-2 days postgame.

Effects of the COVID-19-induced lockdown period on general well-being, perceived stress and activity levels in the Faroe Islands.

AIMS: Detrimental effects on health and well-being were reported during the COVID-19-induced lockdown periods in several countries, but these associations have not been studied in small-scale island societies. This study aimed to examine the lockdown period's impact on general well-being, perceived stress and activity levels in the Faroe Islands. METHODS: We used cross-sectional data from two extensive population-based surveys of the general health conducted in November 2019 (the pre-COVID survey; n=2906), and four to six weeks into the first national lockdown (the lockdown survey; n=1204). RESULTS: A larger proportion of participants in the lockdown survey versus pre-COVID survey displayed excellent/very good self-rated health (68.1% vs. 62.0%; p<0.001), and the same pattern was observed for reporting good quality of life (85.7% vs. 82.7%; p<0.05). These associations remained statistically significant in a logistic regression model after adjusting for characteristics for which varying impact of the pandemic has been shown. Indicators of health behaviour showed that larger proportions of participants kept active during the lockdown survey versus pre-COVID survey, and these differences were statistically significant for physical, mental and spiritual activities (p<0.001). On the other hand, similar stress levels in the pre-COVID/lockdown periods were observed, but stratified analysis showed that participants with a high-stress level displayed better self-rated health in the lockdown period compared to the pre-COVID period (p=0.001). CONCLUSIONS: Findings indicate that self-reported health and quality of life improved during the early phase of the COVID lockdown, and individuals reported higher activity levels associated with good mental health during the COVID-19-induced lockdown period.

Exercise training reduces systemic inflammation and improves general health status in female migraineurs: a randomised controlled trail.

OBJECTIVES: The objectives of this study were to assess the effect of 8 weeks of moderate-intensity aerobic training on permeability inflammatory indicators of matrix metalloproteinases (MMPs) and specific tissue inhibitors of MMPs in female migraineurs. METHODS: Female migraineurs (n = 28, age 32 ± 6) were randomised into two groups: migraine with exercise training (EXE + Mig, n = 13) and migraine without exercise training (NON-EXE + Mig, n = 15). Matched healthy women were also recruited as a healthy control group (CON, n = 15). The EXE-Mig group performed 8 weeks of aerobic training. Pre and post intervention, serum matrix metalloproteinases (MMP-2 and 9) and specific tissue inhibitors of MMPs (TIMP-1 and 2) were measured. In addition, body composition indices and VO2max were determined. RESULTS: Exercise training reduced serum MMP-9 in female migraineurs with between-group changes and a time x group interaction (p < 0.05). In addition, exercise training reduced the serum MMP-9/TIMP-1 ratio in female migraineurs with between-group changes and time x group interaction (p < 0.05). However, no training-induced effect was observed in serum TIMP-1, TIMP-2, MMP-2 contents (p > 0.05) and MMP-2/TIMP-2 ratio (p > 0.05). Finally, exercise training reduced body fat content, WHR and BMI, and improved VO2max (p < 0.01). CONCLUSIONS: Our results demonstrated beneficial effects of aerobic exercise training on some circulatory inflammation factors (MMP9, MMP-9/TIMP-1) and some health indicators in female migraineurs, suggesting that such training can be employed as a non-pharmacological therapeutic method.

Robust arm and leg muscle adaptation to training despite ACE inhibition: a randomized placebo-controlled trial.

PURPOSE: Angiotensin-converting enzyme (ACE) inhibitor treatment is widely applied, but the fact that plasma ACE activity is a potential determinant of training-induced local muscular adaptability is often neglected. Thus, we investigated the hypothesis that ACE inhibition modulates the response to systematic aerobic exercise training on leg and arm muscular adaptations. METHODS: Healthy, untrained, middle-aged participants (40 ± 7 yrs) completed a randomized, double-blinded, placebo-controlled trial. Participants were randomized to placebo (PLA: CaCO3) or ACE inhibitor (ACEi: enalapril) for 8 weeks and completed a supervised, high-intensity exercise training program. Muscular characteristics in the leg and arm were extensively evaluated pre and post-intervention. RESULTS: Forty-eight participants (nACEi = 23, nPLA = 25) completed the trial. Exercise training compliance was above 99%. After training, citrate synthase, 3-hydroxyacyl-CoA dehydrogenase and phosphofructokinase maximal activity were increased in m. vastus lateralis in both groups (all P < 0.05) without statistical differences between them (all time × treatment P > 0.05). In m. deltoideus, citrate synthase maximal activity was upregulated to a greater extent (time × treatment P < 0.05) in PLA (51 [33;69] %) than in ACEi (28 [13;43] %), but the change in 3-hydroxyacyl-CoA dehydrogenase and phosphofructokinase maximal activity was similar between groups. Finally, the training-induced changes in the platelet endothelial cell adhesion molecule-1 protein abundance, a marker of capillary density, were similar in both groups in m. vastus lateralis and m. deltoideus. CONCLUSION: Eight weeks of high-intensity whole-body exercise training improves markers of skeletal muscle mitochondrial oxidative capacity, glycolytic capacity and angiogenesis, with no overall effect of pharmacological ACE inhibition in healthy adults.

Recreational futsal provides broad-spectrum fitness and health benefits but no blood pressure effects in men with treated hypertension - a randomised controlled trial.

We determined the coadjuvant effect of a recreational futsal (RF) programme versus standard care alone (CON) in men with treated arterial hypertension (TAHT). Thirty-nine men with TAHT were randomised to RF (N = 20; 48 ± 8 years; systolic blood pressure [SBP]: 122 ± 14 mmHg) with 2-3 one-hour sessions/week for 3 months, or to CON (N = 19; 51 ± 6 years; SBP: 126 ± 13 mmHg). Participants were assessed at baseline, at 3 months, and after 1 month of training cessation (4 months). Mean training attendance was 60 ± 23%. At 3-months, there were no between-group differences in BP parameters (SBP: 0.44 mmHg; 95% CI: -5.79, 6.67). However, compared to CON, RF was effective for peak oxygen uptake (2.76 mL.min-1.kg-1; 95% CI: 0.26, 5.26), time to exhaustion (1.15 min; 95% CI: 0.59, 1.69), Yo-Yo IE1 performance (365 m; 95% CI: 175, 556), resting heart rate (RHR; -5 b.min-1; 95% CI: -10, -1), glycated haemoglobin (-0.52 mmol/L; 95% CI: -0.84, -0.19), blood glucose (-0.25 mmol/L; 95% CI: -0.44, -0.06), left femur bone mineral content (1.96 g; 95% CI: 0.29, 3.65), and postural balance (-2.3 falls; 95% CI: -3.9, -0.6). Similar findings were observed after 1-month of training cessation, except for RHR and blood glucose that returned to baseline levels in the RF group. In conclusion, RF provides broad-spectrum fitness and health benefits but no BP effects in men with TAHT.

Quantifying training load and intensity in elite male ice hockey according to game-related contextual variables.

We aimed to quantify training load (TL) and intensity during practice sessions according to game-related contextual variables (game outcome, opponent standard, game location) in an elite male ice hockey team. Practice data were collected using a wearable 200-Hz accelerometer, heart rate (HR) recording, and session-rating of perceived exertion (s-RPE) throughout 23 sessions (n = 306 files). The reference team performed a greater number of accelerations, decelerations, spent longer time > 85% maximum HR (t85%HRmax) and reported greater s-RPE after losing a game compared to a win (r = 0.13-0.19). Moreover, a lower number of accelerations, decelerations, t85%HRmax and s-RPE (r = 0.15-0.45) were found before playing against a top-ranked opponent. In contrast, more accelerations, decelerations, longer t85%HRmax and greater s-RPE were observed after playing against a top-ranked team opponent (r = 0.15-0.41). The players performed more accelerations/min, spent more t85%HRmax and reported greater s-RPE before playing an away game (r = 0.13-0.22). Weekly TL seems to slightly increase after losing a game, when preparing a game against a weaker opponent, after playing against a stronger opponent, and when preparing an away game. On the other hand, training intensity seems not to be affected by game-related contextual variables. Thus, ice hockey practitioners involved with TL monitoring should consider the interplay of the numerous variables that influence the volume of prescribed training and the actual training responses in each individual player.

Fibre type- and localisation-specific muscle glycogen utilisation during repeated high-intensity intermittent exercise.

Glycogen particles are situated in key areas of the muscle cell in the vicinity of the main energy-consumption sites and may be utilised heterogeneously dependent on the nature of the metabolic demands. The present study aimed to investigate the time course of fibre type-specific utilisation of muscle glycogen in three distinct subcellular fractions (intermyofibrillar, IMF; intramyofibrillar, Intra; and subsarcolemmal, SS) during repeated high-intensity intermittent exercise. Eighteen moderately to well-trained male participants performed three periods of 10 × 45 s cycling at ∼105% watt max (EX1-EX3) coupled with 5 × 6 s maximal sprints at baseline and after each period. Muscle biopsies were sampled at baseline and after EX1 and EX3. A higher glycogen breakdown rate in type 2 compared to type 1 fibres was found during EX1 for the Intra (-72 vs. -45%) and IMF (-59 vs. -35%) glycogen fractions (P < 0.001) but with no differences for SS glycogen (-52 vs. -40%). In contrast, no fibre type differences were observed during EX2-EX3, where the utilisation of Intra and IMF glycogen in type 2 fibres was reduced, resulting in depletion of all three subcellular fractions to very low levels post-exercise within both fibre types. Importantly, large heterogeneity in single-fibre glycogen utilisation was present with an early depletion of especially Intra glycogen in individual type 2 fibres. In conclusion, there is a clear fibre type- and localisation-specific glycogen utilisation during high-intensity intermittent exercise, which varies with time course of exercise and is characterised by exacerbated pool-specific glycogen depletion at the single-fibre level. KEY POINTS: Muscle glycogen is the major fuel during high-intensity exercise and is stored in distinct subcellular areas of the muscle cell in close vicinity to the main energy consumption sites. In the present study quantitative electron microscopy imaging was used to investigate the utilisation pattern of three distinct subcellular muscle glycogen fractions during repeated high-intensity intermittent exercise. It is shown that the utilisation differs dependent on fibre type, subcellular localisation and time course of exercise and with large single-fibre heterogeneity. These findings expand on our understanding of subcellular muscle glycogen metabolism during exercise and may help us explain how reductions in muscle glycogen can attenuate muscle function even at only moderately lowered whole-muscle glycogen concentrations.

The physiology of ice hockey performance: An update.

Ice hockey is an intense team sport characterized by repeated bursts of fast-paced skating, rapid changes in speed and direction and frequent physical encounters. These are performed in on-ice shifts of ~30-80 s interspersed with longer sequences of passive recovery, resulting in about 15-25 min on-ice time per player. Nearly 50% of the distance is covered at high-intensity skating speeds and with an accentuated intense activity pattern in forwards compared to defensemen. During ice hockey match-play, both aerobic and anaerobic energy systems are significantly challenged, with the heart rate increasing toward maximum levels during each shift, and with great reliance on both glycolytic and phosphagen ATP provision. The high-intensity activity pattern favors muscle glycogen as fuel, leading to pronounced reductions despite the relatively brief playing time, including severe depletion of a substantial proportion of individual fast- and slow-twitch fibers. Player-tracking suggests that the ability to perform high-intensity skating is compromised in the final stages of a game, which is supported by post-game reductions in repeated-sprint ability. Muscle glycogen degradation, in particular in individual fibers, as well as potential dehydration and hyperthermia, may be prime candidates implicated in exacerbated fatigue during the final stages of a game, whereas multiple factors likely interact to impair exercise tolerance during each shift. This includes pronounced PCr degradation, with potential inadequate resynthesis in a proportion of fast-twitch fibers in situations of repeated intense actions. Finally, the recovery pattern is inadequately described, but seems less long-lasting than in other team sports.

Executive summary: Elite women's football-Performance, recovery, diet, and health.

The present special issue of Scandinavian Journal of Medicine & Science in Sports focuses on performance, recovery, diet, and health in elite women's football. Beside this summary, an editorial, topic reviews, and original articles written by several of the most published authors in football research are presented. It is, for example, highlighted that there is a great gender inequality in football research in favor of men, especially within elite football populations. Therefore, the broad-spectrum content of the special issue with focus on several performance areas in women's football, recovery strategies, nutrition, and psychological factors is highly warranted. Several of the topics examined and data presented are examined for the first on elite women's football, and therefore, we hope that this special issue will contribute to gender balance the research and emphasis on football in both genders.

Nutritional optimization for female elite football players-topical review.

Women's football is an intermittent sport characterized by frequent intense actions throughout the match. The high number of matches with limited recovery time played across a long competitive season underlines the importance of nutritional strategies to meet these large physical demands. In order to maximize sport performance and maintain good health, energy intake must be optimal. However, a considerable proportion of female elite football players does not have sufficient energy intake to match the energy expenditure, resulting in low energy availability that might have detrimental physiologic consequences and impair performance. Carbohydrates appear to be the primary fuel covering the total energy supply during match-play, and female elite football players should aim to consume sufficient carbohydrates to meet the requirements of their training program and to optimize the replenishment of muscle glycogen stores between training bouts and matches. However, several macro- and micronutrients are important for ensuring sufficient energy and nutrients for performance optimization and for overall health status in female elite football players. The inadequacy of macro-and micronutrients in the diet of these athletes may impair performance and training adaptations, and increase the risk of health disorders, compromising the player's professional career. In this topical review, we present knowledge and relevant nutritional recommendations for elite female football players for the benefit of sports nutritionists, dietitians, sports scientists, healthcare specialists, and applied researchers. We focus on dietary intake and cover the most pertinent topics in sports nutrition for the relevant physical demands in female elite football players as follows: energy intake, macronutrient and micronutrient requirements and optimal composition of the everyday diet, nutritional and hydration strategies to optimize performance and recovery, potential ergogenic effects of authorized relevant supplements, and future research considerations.

Skeletal muscle phenotype and game performance in elite women football players.

We combined game activity analyses with skeletal muscle phenotypes and comprehensive physiological testing to elucidate factors of importance for physical performance in elite women's football. GPS-data from an experimental game, sprint and endurance testing, and muscle tissue analysis of metabolic enzyme activity, protein expression and fiber type composition were completed for international top-level women players (n = 20; age; 23 ± 4 yrs, height; 166 ± 10 cm, weight; 60 ± 8 kg; VO2max ; 51 ± 6 ml/min/kg). Muscle monocarboxylate transporter 4 (MCT4) protein expression explained 46% of the variance in total game distance, while the ability to maintain high-intensity running (HIR) during the final 15 min of the game correlated to myosin heavy chain 1 (MHCI) and Na+ -K+ ATPase ß1, FXYD1 (phospholemman) and superoxide dismutase 2 (SOD2) protein expression (range: r = 0.51-0.71; all p < 0.05). Total HIR distance correlated with (MHCIIa) protein expression (r = 0.51; p < 0.05), while muscle Na+ /H+ exchanger 1 (NHE1) protein explained 36% of the variance in game sprint distance (p < 0.05). Total game accelerations (actions >4 m/s2 ) correlated with platelet endothelial cell adhesion molecule (PECAM-1) protein expression (r = 0.51; p < 0.05), while concentric knee flexor strength explained 42-62% of the variance in intense decelerations (>4 m/s2 ). In conclusion, for elite women players' game endurance performance and resistance to end-game fatigue were affected by monocarboxylate transporter expression and myosin heavy chain profile. HIR was also correlated to ion transporter expression and muscle antioxidative capacity. Finally, the importance of functional strength and measures of muscle vascularization in relation to total game decelerations and accelerations, respectively, illustrates the complex physiological demands in elite women's football.

Muscle metabolism and impaired sprint performance in an elite women's football game.

The present study examined skeletal muscle metabolism and changes in repeated sprint performance during match play for n = 20 competitive elite women outfield players. We obtained musculus vastus lateralis biopsies and blood samples before, after, and following intense periods in each half of a friendly match, along with 5 × 30-meter sprint tests and movement pattern analyses (10-Hz S5 Global Positioning System [GPS]). Muscle glycogen decreased by 39% and 42% after an intense period of the second half and after the match, respectively, compared to baseline (p < 0.05). Post-match, 80% type I fibers and 69% type II fibers were almost empty or completely empty of glycogen. Muscle lactate was higher (p < 0.05) after the intense period of the first half and post-match compared to baseline (14.3 ± 4.6 (±SEM) and 12.9 ± 5.7 vs. 6.4 ± 3.7 mmol/kg d.w.). Muscle phosphocreatine was reduced (p < 0.05) by 16% and 12%, respectively, after an intense period in the first and second half compared to baseline. Blood lactate and glucose increased during the match and peaked at 8.4 ± 2.0 and 7.9 ± 1.2 mmol/L, respectively. Mean 5 × 30 m sprint time declined by 3.2 ± 1.7 and 7.0 ± 2.1% after the first and second half, respectively, and 4.7 ± 1.6% (p < 0.05) after an intense period in the first half compared to baseline. In conclusion, match play in elite female football players resulted in marked glycogen depletion in both fiber types, which may explain fatigue at the end of a match. Repeated sprint ability was impaired after intense periods in the first half and after both halves, which may be associated with the observed muscle metabolite perturbations.

Social inequality in type 2 diabetes mellitus in the Faroe Islands: a cross-sectional study.

Aims: The Faroe Islands is considered a homogeneous society and has a low Gini coefficient, but the knowledge about the social distribution of health and disease is sparse. In a large population-based sample we investigated: (a) the association between socioeconomic position defined by level of education and the prevalence of type 2 diabetes mellitus by self-report in the Faroe Islands; and (b) to what degree lifestyle factors mediate the association. Methods: We used cross-sectional data from the population-based Public Health Survey Faroes 2015 (n=1095). We present odds ratios for type 2 diabetes mellitus by socioeconomic position from logistic regression models. In our main model we adjusted for potential confounders and in a secondary model we additionally adjusted for potential mediating lifestyle factors. Results: Individuals with middle and low levels of education display higher odds ratios of type 2 diabetes mellitus of 2.80 (95% confidence interval 1.32-5.92) and 4.65 (95% confidence interval 1.93-11.17) in adjusted analysis, respectively, compared to their counterparts with high education. After adjustment for potentially mediating lifestyle factors the estimates were attenuated slightly, but a significant statistical association remained, with lifestyle-related mediating factors in total explaining 21% for middle education and 34% for low education participants. Conclusions: Our results demonstrate that there may be a social gradient in the distribution of type 2 diabetes mellitus in the Faroe Islands, and that the association is partly mediated by lifestyle factors.

Acute arm and leg muscle glycogen and metabolite responses to small-sided football games in healthy young men.

PURPOSE: Studies have indicated upper body involvement during football, provoking long-term muscular adaptations. This study aimed at examining the acute metabolic response in upper and lower body skeletal muscle to football training organized as small-sided games (SSG). METHODS: Ten healthy male recreational football players [age 24 ± 1 (± SD) yrs; height 183 ± 4 cm; body mass 83.1 ± 9.7 kg; body fat 15.5 ± 5.4%] completed 1-h 5v5 SSG (4 × 12 min interspersed with 4-min recovery periods). Muscle biopsies were obtained from m. vastus lateralis (VL) and m. deltoideus (DE) pre- and post-SSG for muscle glycogen and metabolite analyses. Blood lactate samples were obtained at rest, middle and end of the SSG. RESULTS: Muscle glycogen in VL decreased (P < 0.01) by 21% and tended (P = 0.08) to decrease in DE by 13%. Muscle lactate increased in VL (117%; P < 0.001) and DE (81%; P < 0.001) during the game, while blood lactate rose threefold. Muscle ATP and PCr were unaltered, but intermuscular differences were detected for ATP at both time points (P < 0.001) and for PCr at pre-SSG (P < 0.05) with VL demonstrating higher values than DE, while muscle creatine rose in VL (P < 0.001) by 41% and by 22% in DE (P = 0.02). Baseline citrate synthase maximal activity was higher (P < 0.05) in VL compared to DE, whereas baseline muscle lactate concentration was higher (P < 0.05) in DE than VL. CONCLUSION: The upper body may be extensively involved during football play, but besides a rise in muscle lactate in the deltoideus muscle similar to the leg muscles, the present study did not demonstrate acute metabolic changes of an order that may explain the previously reported training effect of football play in the upper extremities.

Use of Rating of Perceived Exertion-Based Training Load in Elite Ice Hockey Training and Match-Play.

ABSTRACT: Rago, V, Vigh-Larsen, JF, Deylami, K, Muschinsky, A, and Mohr, M. Use of rating of perceived exertion-based training load in elite ice hockey training and match-play. J Strength Cond Res 36(10): 2837-2843, 2022-Training load (TL) based on the subjective rating of perceived exertion (RPE) may be a useful athlete monitoring alternative when wearable technology is unavailable. The aim of this study was to examine the validity of RPE-based TL monitoring in elite ice hockey. A male ice hockey team ( n = 18) was monitored using a 200-Hz accelerometer, heart rate (HR) and RPE (0-10 scale), throughout a 4-week competitive period ( n = 309 individual observations). Session-RPE (RPE × duration) averaged 244.8 ± 135.2 and 728.6 ± 150.9 arbitrary units (AU) during practice sessions and during official games, respectively. The smallest worthwhile change was 19.8 AU. Within-individual correlations between session-RPE and total accelerations >0.5 m·s -2 (Acc tot ), accelerations >2 m·s -2 (Acc2), total decelerations >-0.5 m·s -2 (Dec tot ), decelerations < -2 m·s -2 (Dec2), time > 85% maximum HR, Edwards' TL, and modified training impulse were very large ( r = 0.70-0.89; p < 0.001). In addition, correlations between RPE and measures of exercise intensity (Acc tot per min, Acc2 per min, Dec tot per min, mean HR, and peak HR) were small ( r = 0.02-0.29; p < 0.05) except for Dec2 being unclear ( p = 0.686). Differences in intensity parameters between RPE range (easy to very hard, 2-7 AU) were small ( r = 0.22-0.31; p < 0.05). The session-RPE method can be used as a global indicator of TL in ice hockey. Specific ranges of time-motion and HR intensity variables can be demarcated between RPE categories (easy to very hard; 2-7 AU). Accounting for training volume (session-RPE) more accurately reflects objective methods of TL based on accelerative efforts and HR, than the RPE score (based on the perception of the intensity).