The novel coronavirus disease 2019 (COVID-19) seems to be having a major impact on physical activity behaviours globally. The pandemic has forced many people around the world to stay at home and ...self-isolate for a period of time. WHO recommends 60 min/day of moderate-to-vigorous physical activity for 6-17-yr-olds, and 75 min/wk of vigorous or 150 min/wk of moderate physical activity for adults and elderly, including 3 and 2 days/wk, respectively, with muscle and bone strengthening. Practical recommendations for staying active at home, with aerobic exercise training on a bike or rowing ergometer, bodyweight training, dance and active video gaming, can aid to counteract the detrimental physical and mental side-effects of the COVID-19 protective lifestyle regulations. This commentary provides useful information on home-based physical activity for sedentary people across the lifespan, including children and adolescence, that can be undertaken during the present pandemic or other outbreaks of infectious disease.
Full text
Available for:
BFBNIB, FSPLJ, IZUM, KILJ, NUK, PILJ, SAZU, UL, UM, UPUK
The study examined Yo-Yo intermittent recovery level 2 (YYIR2) and submaximal YYIR1 test performances in 172 male semi-professional football players (age; 25.8 ± 4.1 years) representing all teams in ...a top league at pre-season, start-season, mid-season and end-season. YYIR2 performance was 847 ± 227 m (±SD) at pre-season and rose (P < 0.05) by 128 ± 113 m to 975 ± 205 m at start of season and further (P < 0.05) by 59 ± 102 m to 1034 ± 211 m at mid-season. Submaximal YYIR1 HR was 90.9 ± 4.2% HR
max
at pre-season, which was higher (P < 0.05) than at start, mid and end of season (87.0 ± 3.9, 85.9 ± 4.1 and 87.0 ± 3.7% HR
max
, respectively). Peak YYIR2 performance and minimum YYIR1 HR were 1068 ± 193 m and 85.1 ± 3.8% HR
max
, respectively, with ~50% of the players peaking at mid-season. Top-teams and middle-teams had higher (P < 0.05) peak YYIR2 scores (1094 ± 205 and 1121 ± 152 m, respectively) than bottom-teams (992 ± 185 m). YYIR2 performance was 16% higher (P < 0.05) and YYIR1 HR was 1.4% HR
max
lower (P < 0.05) for regular players than non-regular players at pre-season and remained lower (P < 0.05) throughout the season. Central defenders had poorer (P < 0.05) YYIR performances compared to other positional roles. In conclusion, YYIR performances are highly variable within a football league over a season and are influenced by league ranking, regularity of competitive play and playing position.
Full text
Available for:
BFBNIB, FSPLJ, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
In soccer, the players perform intermittent work. Despite the players performing low-intensity activities for more than 70% of the game, heart rate and body temperature measurements suggest that the ...average oxygen uptake for elite soccer players is around 70% of maximum (VdotO
2max
). This may be partly explained by the 150 - 250 brief intense actions a top-class player performs during a game, which also indicates that the rates of creatine phosphate (CP) utilization and glycolysis are frequently high during a game. Muscle glycogen is probably the most important substrate for energy production, and fatigue towards the end of a game may be related to depletion of glycogen in some muscle fibres. Blood free-fatty acids (FFAs) increase progressively during a game, partly compensating for the progressive lowering of muscle glycogen. Fatigue also occurs temporarily during matches, but it is still unclear what causes the reduced ability to perform maximally. There are major individual differences in the physical demands of players during a game related to physical capacity and tactical role in the team. These differences should be taken into account when planning the training and nutritional strategies of top-class players, who require a significant energy intake during a week.
Full text
Available for:
BFBNIB, FSPLJ, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
We aimed at examining the criterion validity and sensitivity of heart-rate recovery (HRRec) in profiling cardiorespiratory fitness in male recreational football players in the untrained and trained ...status, using endurance field-tests. Thirty-two male untrained subjects (age 40 ± 6 years, VO2max 41.7 ± 5.7 ml·kg-1·min-1, body mass 82.7 ± 9.8 kg, stature 173.3 ± 7.4 cm) participated in a 12-week (2‒3 sessions per week) recreational football intervention and were tested pre- and post-intervention (i.e. untrained and trained status). The participants performed three intermittent field tests for aerobic performance assessment, namely Yo-Yo intermittent endurance level 1 (YYIE1) and level 2 (YYIE2) tests, and Yo-Yo intermittent recovery level 1 (YYIR1) test. VO2max was assessed by performing a progressive maximal treadmill test (TT) and maximal HR (HRmax) determined as the maximal value across the testing conditions (i.e., Yo-Yo intermittent tests or TT). HRRec was calculated as the difference between Yo-Yo tests' HRpeak or HRmax and HR at 30 s (HR30), 60 s (HR60) and 120 s (HR120) and considered as beats·min-1 (absolute) and as % of tests' HRpeak or HRmax values. Significant post-intervention improvements (p<0.0001) were shown in VO2max (8.6%) and Yo-Yo tests performance (23-35%). Trivial to small (p>0.05) associations were found between VO2max and HRRec (r = -0.05-0.27, p>0.05) across the Yo-Yo tests, and training status either expressed as percentage of HRpeak or HRmax. The results of this study do not support the use of field-test derived HRRec to track cardiorespiratory fitness and training status in adult male recreational football players.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
ABSTRACTKrustrup, P and Mohr, M. Physical demands in competitive ultimate Frisbee. J Strength Cond Res 29(12)3386–3391, 2015—The objective was to study game demands in competitive ultimate Frisbee by ...performing match analysis during a game. Thirteen moderately trained (Yo-Yo intermittent recovery test levels 1 and 2 Yo-Yo IR1 and IR2 performance1790 ± 382 m and 657 ± 225 m, respectively) competitive male ultimate Frisbee athletes played a game in which activity profile using Global Positioning System (GPS) technology and heart rate (HR) were recorded. Game HRmean and HRpeak were 82 ± 2% and 99 ± 1% of maximum heart rate, respectively. Total game distance was 4.70 ± 0.47 km, of which 0.63 ± 0.14 km was high-intensity running and 0.21 ± 0.11 km was sprinting. In the second half, 10% less (p ≤ 0.05) ground was covered with high-intensity running compared with the first half (0.28 ± 0.08 km vs. 0.31 ± 0.07 km). Less (43–47%; p ≤ 0.05) high-intensity running was performed in the third 9-minute period of each half compared with the first two 9-minute periods of the same half. Players performed 17.4 ± 5.7 sprints during the match. Yo-Yo IR2 performance correlated to the amount of high-intensity running in the last 9 minutes of both halves (r = 0.69, p ≤ 0.05), whereas Yo-Yo IR1 performance correlated with total sprint distance (r = 0.74, p ≤ 0.05). Ultimate Frisbee is an intense intermittent team sport with high cardiovascular loading and clear indications of fatigue toward the end of each half. Yo-Yo IR test performances correlate with physical match performance.
Over the past 10 years, researchers have studied the effects of recreational football training as a health-promoting activity for participants across the lifespan. This has important public health ...implications as over 400 million people play football annually. Results from the first randomised controlled trial, published in the BJSM in January 2009, showed that football increased maximal oxygen uptake and muscle and bone mass, and lowered fat percentage and blood pressure, in untrained men, and since then more than 70 articles about football for health have been published, including publications in two supplements of the Scandinavian Journal of Medicine and Science in Sports in 2010 and 2014, prior to the FIFA World Cup tournaments in South Africa and Brazil. While studies of football training effects have also been performed in women and children, this article reviews the current evidence linking recreational football training with favourable effects in the prevention and treatment of disease in adult men.
Key points
In human skeletal muscles, the current view is that the capacity for mitochondrial energy production, and thus endurance capacity, is set by the mitochondria volume.
However, increasing ...the mitochondrial inner membrane surface comprises an alternative mechanism for increasing the energy production capacity.
In the present study, we show that mitochondrial inner membranes in leg muscles of endurance‐trained athletes have an increased ratio of surface per mitochondrial volume.
We show a positive correlation between this ratio and whole body oxygen uptake and muscle fibre mitochondrial content.
The results obtained in the present study help us to understand modulation of mitochondrial function, as well as how mitochondria can increase their oxidative capacity with increased demand.
Mitochondrial energy production involves the movement of protons down a large electrochemical gradient via ATP synthase located on the folded inner membrane, known as cristae. In mammalian skeletal muscle, the density of cristae in mitochondria is assumed to be constant. However, recent experimental studies have shown that respiration per mitochondria varies. Modelling studies have hypothesized that this variation in respiration per mitochondria depends on plasticity in cristae density, although current evidence for such a mechanism is lacking. In the present study, we confirm this hypothesis by showing that, in human skeletal muscle, and in contrast to the current view, the mitochondrial cristae density is not constant but, instead, exhibits plasticity with long‐term endurance training. Furthermore, we show that frequently recruited mitochondria‐enriched fibres have significantly increased cristae density and that, at the whole‐body level, muscle mitochondrial cristae density is a better predictor of maximal oxygen uptake rate than muscle mitochondrial volume. Our findings establish an elevating mitochondrial cristae density as a regulatory mechanism for increasing metabolic power in human skeletal muscle. We propose that this mechanism allows evasion of the trade‐off between cell occupancy by mitochondria and other cellular constituents, as well as improved metabolic capacity and fuel catabolism during prolonged elevated energy requirements.
Key points
In human skeletal muscles, the current view is that the capacity for mitochondrial energy production, and thus endurance capacity, is set by the mitochondria volume.
However, increasing the mitochondrial inner membrane surface comprises an alternative mechanism for increasing the energy production capacity.
In the present study, we show that mitochondrial inner membranes in leg muscles of endurance‐trained athletes have an increased ratio of surface per mitochondrial volume.
We show a positive correlation between this ratio and whole body oxygen uptake and muscle fibre mitochondrial content.
The results obtained in the present study help us to understand modulation of mitochondrial function, as well as how mitochondria can increase their oxidative capacity with increased demand.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
To examine the activity profile and physical loading of elite female soccer players during match play and to study the relationship between training status and physical match performance.
Time-motion ...analysis and HR recordings were performed on 14 elite female soccer players during competitive matches. In addition, the players carried out a laboratory treadmill test and the Yo-Yo intermittent recovery test.
The total distance covered during a game was 10.3 km (range: 9.7-11.3) with high-intensity running (HIR) accounting for 1.31 km (0.71-1.70). HIR was performed 125 times (72-159) for 2.3 s (2.0-2.4) on average. The average and peak HR in a game were 167 beats per minute (bpm) (152-186) and 186 (171-205), respectively, corresponding to 87% (81-93) and 97% (96-100) of HR(max). Maximal pulmonary oxygen uptake (VO2max) was 49.4 mL.min(-1).kg(-1) (43.4-56.8), and incremental treadmill test (ITT) performance was 4.49 min (3.38-5.17). The Yo-Yo test performance was 1379 m (600-1960). The total distance covered during match play did not correlate with VO2max or ITT performance but correlated with the Yo-Yo test result (r = 0.56, P < 0.05). Significant positive correlations were observed between HIR and VO2max (r = 0.81, P < 0.05), ITT (r = 0.82, P < 0.05), and Yo-Yo test performance (r = 0.76, P < 0.05). No relationship was observed between HR(max) during match play and any of the performance measures.
The present study demonstrated that 1) HIR during games varies markedly between elite female soccer players, 2) all players have high HR throughout a competitive game with periods of near-maximal values, 3) the distance covered by HIR during match play is closely related to the physical capacity, and 4) the Yo-Yo intermittent recovery test can be used as an indicator of the physical match performance of elite female players.
The study aims were to describe positional differences in the acceleration and sprint profiles of professional football players in match-play, and analyse start speeds required based on the intensity ...of accelerations and decelerations. This longitudinal study was conducted over thirteen competitive microcycles in a professional football team from LaLiga 123. Data were collected through electronic performance tracking systems. Every player was categorised based on the playing position: central defender (CD), full-back (FB), forward (FW), midfielder (MF), and wide midfielder (WMF). In respect of acceleration profile, positional differences were found for all variables (p < 0.05), except average magnitude of accelerations (ACCAVG, p = 0.56) and decelerations (DECAVG, p = 0.76). The sprint profile also showed positional differences for all variables (p < 0.05), apart from sprint duration (p = 0.07). In addition, although low-intensity accelerations required significantly greater start speeds (Vo) than high-intensity accelerations in WMF (0.4 ± 0.2 km/h; p < 0.05) and FW (0.4 ± 0.2 km/h; p < 0.05), no significant differences (p > 0.05) were found in CD, FB, and MF. However, high-intensity decelerations were performed at significantly higher Vo than low-intensity decelerations in MF (2.65 ± 0.1 km/h; p < 0.05), FW (3.3 ± 0.1 km/h; p < 0.05), FB (3.9 ± 0.4 km/h; p < 0.05), WMF (4.3 ± 0.3 km/h; p < 0.05), and CD (4.1 ± 0.7 km/h; p < 0.05). Therefore, positional differences exist for most variables of the acceleration and sprint profiles. In addition, different Vo were observed between high-intensity and low-intensity accelerations as well as high-intensity and low-intensity decelerations.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The COVID-19 pandemic has changed the conditions for competitive football around the globe dramatically. Several competitions and leagues have been cancelled or postponed. Players have firstly been ...forced to training in solitude. In a second stage, players start training in small groups with strict contact restriction and return to competitive play might occur after only few weeks of normal team training preparation. These special circumstances are likely to impact football performance and injury risk in the upcoming competitions. Thus, clubs, coaching and medical staff, as well as players are challenged on the prioritization of fitness and performance, which easily can create several "catch-22-dilemmas". The present article presents views on fitness training, physical preparation and recovery during these uncommon conditions, and how elite football players can return to the competitive field well-prepared for post-crisis football endeavours around the world. Due to the multifaceted physiological demands in elite football, the long recovery requirements after match-play and an upcoming reality with many games within a short period, elite football players, managers and clubs may face extraordinary challenges associated with return to play under the current circumstances.
Full text
Available for:
BFBNIB, FSPLJ, IZUM, KILJ, NUK, PILJ, SAZU, UL, UM, UPUK
PDF
