Magni Mohr

Muscle damage, inflammatory, immune and performance responses to three football games in 1 week in competitive male players

PurposeWe examined effects of a three-game, 1-week microcycle (G1, G2, G3) on recovery of performance and inflammatory responses in professional male footballers.MethodsPlayers were randomized into an experimental (EXP; N = 20) and a control group (CON; N = 20). Blood was drawn and repeated sprint ability (RSA), muscle soreness and knee range of motion (KJRM) were determined pre- and post-games and during recovery.ResultsHigh-intensity running during G2 was 7–14 % less compared to G1 and G3. RSA declined in EXP by 2–9 % 3 days post-game with G2 causing the greatest performance impairment. In EXP, game play increased muscle soreness (~sevenfold) compared to CON with G2 inducing the greatest rise, while KJRM was attenuated post-game in EXP compared to CON (5–7 %) and recovered slower post G2 and G3 than G1. CK, CRP, sVCAM-1, sP-Selectin and cortisol peaked 48 h post-games with G2 eliciting the greatest increase. Leukocyte count, testosterone, IL-1β and IL6 responses, although altered 24 h post each game, were comparable among games. Plasma TBARS and protein carbonyls rose by ~50 % post-games with G2 eliciting the greatest increase 48 h of recovery. Reduced to oxidized glutathione ratio declined for 24 h post all games with G2 displaying the slowest recovery. Total antioxidant capacity and glutathione peroxidase activity increased (9–56 %) for 48 h in response to game play.ConclusionIn summary, post-game performance recovery and inflammatory adaptations in response to a three-game weekly microcycle displayed a different response pattern, with strong indications of a largest physiological stress and fatigue after the middle game that was preceded by only a 3-day recovery.

The mechanistic bases of the power–time relationship: muscle metabolic responses and relationships to muscle fibre type

The power‐asymptote (critical power; CP) of the hyperbolic power–time relationship for high‐intensity exercise defines a threshold between steady‐state and non‐steady‐state exercise intensities and the curvature constant (W′) indicates a fixed capacity for work >CP that is related to a loss of muscular efficiency. The present study reports novel evidence on the muscle metabolic underpinnings of CP and W′ during whole‐body exercise and their relationships to muscle fibre type. We show that the W′ is not correlated with muscle fibre type distribution and that it represents an elevated energy contribution from both oxidative and glycolytic/glycogenolytic metabolism. We show that there is a positive correlation between CP and highly oxidative type I muscle fibres and that muscle metabolic steady‐state is attainable CP. Our findings indicate a mechanistic link between the bioenergetic characteristics of muscle fibre types and the power–time relationship for high‐intensity exercise.

Yo-Yo intermittent recovery test performances within an entire football league during a full season

Abstract 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% HRmax 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% HRmax, respectively). Peak YYIR2 performance and minimum YYIR1 HR were 1068 ± 193 m and 85.1 ± 3.8% HRmax, 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% HRmax 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.

Caffeine supplementation does not affect match activities and fatigue resistance during match play in young football players

Abstract The study examined the effect of caffeine supplementation on match activities and development of fatigue during a football match. In a randomised, double-blind cross-over design, two experimental football games separated by 7 days were organised between the junior teams of two professional football clubs (17.6 ± 1.1 years (±s), 71.7 ± 6.9 kg, 13.9% ± 5.0% body fat). The players ingested either a capsule of 6 mg · kg−1 b.w. caffeine or placebo (dextrose) 65 min prior to the matches. Match activities were assessed using the ZXY match analysis system, and a Yo-Yo intermittent recovery test–level 2 (Yo-Yo IR2) was conducted immediately post-game. Heart rate was monitored throughout the game, and blood samples were obtained at baseline, half-time and after the game. There were no differences between caffeine and placebo regarding total distance covered (10,062 ± 916 vs 9854 ± 901 m), high-intensity running (557 ± 178 vs 642 ± 240 m), sprinting distance (109 ± 58 vs 112 ± 69 m) or acceleration counts (123 ± 31 vs 126 ± 24). In both trials, players displayed lower (P < 0.05) values in total distance and acceleration counts in the last 15 min compared to all other 15-min periods of the matches. Post-game Yo-Yo IR2 performance was not different between game trials (caffeine: 829 ± 322 m; placebo 819 ± 289 m). In conclusion, oral caffeine administration does not appear to have an ergogenic effect in young football players during match play.

Broad-spectrum physical fitness benefits of recreational football: a systematic review and meta-analysis

Background A previous meta-analysis showed that maximal oxygen uptake increased by 3.51 mL/kg/min (95% CI 3.07 to 4.15) during a recreational football programme of 3–6 months in comparison with continuous moderate-intensity running, strength training or a passive control group. In addition, narrative reviews have demonstrated beneficial effects of recreational football on physical fitness and health status. Objective The purpose of this systematic review and meta-analysis was to evaluate the magnitude of effects of recreational football on blood pressure, body composition, lipid profile and muscular fitness with reference to age, gender and health status. Design Systematic review and meta-analysis. Data sources MEDLINE, PubMed, SPORTDiscus, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Google Scholar were searched prior to 1 February 2017. In addition, Google Scholar alerts were set up in January 2012 to identify potential papers with the following key terms: recreational football, recreational soccer, street football and street soccer. Eligibility criteria for selecting studies Randomised and matched controlled trials with participants allocated to a recreational football group or any other type of exercises or passive control group were included. Training programmes had to last at least 2 weeks to meet the inclusion criteria. The primary outcome measures were blood pressure, resting heart rate, body composition, muscular fitness, and blood lipids and glucose tolerance. A total of 31 papers met the inclusion criteria and were included. Results The effect of recreational football on systolic blood pressure (SBP) versus no-exercise controls was most likely extremely largely beneficial (effect size (ES)=4.20 mm Hg; 95% CI 1.87 to 6.53). In addition, a most likely very large beneficial (ES=3.89 mm Hg; 95% CI 2.33 to 5.44) effect was observed for diastolic blood pressure (DBP), when compared with non-active groups. Furthermore, a most likely extremely large beneficial effect was shown for SBP and DBP in participants with mild hypertension (11 and 7 mm Hg decrease, respectively) and participants with prehypertension (10 and 7 mm Hg decrease, respectively). Meta-analysis of recreational football determined the impact on resting heart rate as most likely extremely largely beneficial (ES=6.03 beats/min; 95% CI 4.43 to 7.64) when compared with non-active groups. The observed recreational football effect on fat mass was most likely largely beneficial (ES=1.72 kg; 95% CI 0.86 to 2.58) and the effect on countermovement jump (CMJ) performance was most likely very largely beneficial (ES=2.27 cm; 95% CI 1.29 to 3.25) when compared with non-active groups. Possibly beneficial decreases were found in low-density lipoprotein levels (ES=0.21 mmol/L; 95% CI 0.06 to 0.36). Possibly largely beneficial effect was observed for DBP in comparison with continuous running training. Small harmful and unclear results were noted for SBP, fat and lean body mass, body mass index, as well as muscular fitness when compared with running and Zumba training. Conclusion The present meta-analysis demonstrated multiple broad-spectrum benefits of recreational football on health-related physical fitness compared with no-exercise controls, including improvements in blood pressure, resting heart rate, fat mass, low-density lipoprotein cholesterol and CMJ performance. Additionally, recreational football is efficient and effective as Zumba and continuous running exercise regimens with highlighted social, motivational and competitive components.

Broad-spectrum health improvements with one year of soccer training in inactive mildly hypertensive middle-aged women

The study tested the hypothesis that long‐term soccer training has positive impact on cardiovascular profile, body composition, bone health, and physical capacity in inactive, pre‐menopausal women with mild hypertension. The study applied a randomized controlled design in which physically inactive middle‐aged women were separated into a soccer training group (n=19; SOC) and a control group (n=12; CON). SOC performed 128±29 (±SD) one‐h small‐sided soccer training sessions over one year. Blood pressure, body composition, blood lipid profile, and fitness level were determined pre‐ and post‐intervention. Over one year, mean arterial pressure decreased more in SOC than in CON (−5±7 vs +4±5 mmHg; P<.05). Total‐body fat mass decreased more (P<.05) in SOC than in CON (−2.5±2.5 vs +0.6±3.2 kg; P<.05), while the change scores for lean body mass were not significantly different in SOC (2.6±2.7 kg) compared to CON (1.1±1.9 kg, P=.09). Over one year, change scores in whole‐body bone mineral density (0.004±0.032 vs −0.019±0.026 g·cm2) as well as bone mineral content (30±70 vs −39±113 g) were positive in SOC compared to CON (P<.05). Post‐intervention plasma triglycerides decreased more (−0.1±0.7 vs +0.2±0.2 mmol·L−1) and HDL cholesterol increased more (0.2±0.7 vs −0.2±0.2 mmol·L−1) in SOC than in CON (P<.05). Yo‐Yo intermittent endurance level 1 (122±105 vs 2±21%) and 20‐m sprint performance (6±6 vs −1±2%) increased more (P<.05) in SOC than in CON. In conclusion, long‐term soccer training resulted in broad‐spectrum improvements in the health profile of untrained, pre‐menopausal women with mild hypertension, including cardiovascular, metabolic, and musculo‐skeletal benefits.

Plantar flexor neuromuscular adjustments following match-play football in hot and cool conditions

We assessed neuromuscular fatigue and recovery of the plantar flexors after playing football with or without severe heat stress. Neuromuscular characteristics of the plantar flexors were assessed in 17 male players at baseline and ∼30 min, 24, and 48 h after two 90‐min football matches in temperate (∼20 °C and 55% rH) and hot (∼43 °C and 20% rH) environments. Measurements included maximal voluntary strength, muscle activation, twitch contractile properties, and rate of torque development and soleus EMG (i.e., root mean square activity) rise from 0 to 30, −50, −100, and −200 ms during maximal isometric contractions for plantar flexors. Voluntary activation and peak twitch torque were equally reduced (−1.5% and −16.5%, respectively; P < 0.05) post‐matches relative to baseline in both conditions, the latter persisting for at least 48 h, whereas strength losses (∼5%) were not significant. Absolute explosive force production declined (P < 0.05) 30 ms after contraction onset independently of condition, with no change at any other epochs. Globally, normalized rate of force development and soleus EMG activity rise values remained unchanged. In football, match‐induced alterations in maximal and rapid torque production capacities of the plantar flexors are moderate and do not differ after competing in temperate and hot environments.

High-Intensity Training Improves Exercise Performance in Elite Women Volleyball Players During a Competitive Season

Abstract Purkhús, E, Krustrup, P, and Mohr, M. High-intensity training improves exercise performance in elite women volleyball players during a competitive season. J Strength Cond Res 30(11): 3066–3072, 2016—Elite women volleyball players (n = 25; mean ± SD: age, 19 ± 5 years; height, 171 ± 7 cm; weight, 63 ± 10 kg) volunteered to participate in the study. They were randomized into a high-intensity training (HIT; n = 13) group and a control (CON; n = 12) group. In addition to the normal team training and games, HIT performed 6–10 × 30-seconds all-out running intervals separated by 3-minute recovery periods 3 times per week during a 4-week in-season period whereas CON only completed the team training sessions and games. Preintervention and postintervention, all players completed the arrowhead agility test (AAT), a repeated sprint test (RST; 5 × 30 meters separated by 25 seconds of recovery), and the Yo-Yo Intermittent Recovery level 2 test (Yo-Yo IR2) followed by a-10 minute rest period and the Yo-Yo IR1 test. Mean running distance during HIT in week 1 was 152 ± 4 m and increased (p ⩽ 0.05) by 4.6% (159 ± 3 m) in week 4. The AAT performance improved (p ⩽ 0.05) by 2.3% (18.87 ± 0.97–18.44 ± 1.06 seconds) and RST by 4.3% postintervention in the HIT group only. Baseline RST fatigue index was 7.0 ± 2.9 and 6.2 ± 5.0% in HIT and CON, respectively, but was lowered (p ⩽ 0.05) to 2.7 ± 3.0% posttraining in HIT and remained unaltered in CON (5.5 ± 5.0%). In HIT, Yo-Yo IR2 and Yo-Yo IR1 performance improved by 12.6 and 18.3% postintervention, respectively, with greater (p ⩽ 0.05) Yo-yo IR1 change scores than in CON. In conclusion, additional high-intensity in-season training performed as interval running improved agility, repeated sprint ability, and high-intensity intermittent exercise performance in elite women volleyball players.

Evaluating a Nationwide Recreational Football Intervention: Recruitment, Attendance, Adherence, Exercise Intensity, and Health Effects

The present study evaluated a nationwide exercise intervention with Football Fitness in a small-scale society. In all, 741 adult participants (20–72 yrs) were successfully recruited for Football Fitness training in local football clubs, corresponding to 2.1% of the adult population. A preintervention test battery including resting heart rate (RHR), blood pressure, and body mass measurements along with performance tests (Yo-Yo Intermittent Endurance level 1 (Yo-Yo IE1), the Arrowhead Agility Test, and the Flamingo Balance Test) were performed (n = 502). Training attendance (n = 310) was 1.6 ± 0.2 sessions per week (range: 0.6–2.9), corresponding to 28.8 ± 1.0 sessions during the 18 wk intervention period. After 18 wks mean arterial pressure (MAP) was −2.7 ± 0.7 mmHg lower (P < 0.05; n = 151) with even greater (P < 0.05) reductions for those with baseline MAP values >99 mmHg (−5.6 ± 1.5 mmHg; n = 50). RHR was lowered (P < 0.05) by 6 bpm after intervention (77 ± 1 to 71 ± 1 bpm). Yo-Yo IE1 performance increased by 41% (540 ± 27 to 752 ± 45 m), while agility and postural balance were improved (P < 0.05) by ~6 and ~45%, respectively. In conclusion, Football Fitness was shown to be a successful health-promoting nationwide training intervention for adult participants with an extraordinary recruitment, a high attendance rate, moderate adherence, high exercise intensity, and marked benefits in cardiovascular health profile and fitness.

Is L-Carnitine Supplementation Beneficial in 3-Methylcrotonyl-CoA Carboxylase Deficiency?

BACKGROUND 3-Methylcrotonyl-CoA carboxylase deficiency (3-MCCd) is an autosomal recessive disorder in the catabolism of leucine. In the present study, we investigated the current and prior medical condition of patients with 3-MCCd in the Faroe Islands and their carnitine levels in blood, urine and muscle tissue with and without L-carnitine supplementation to evaluate the current treatment strategy of not recommending L-carnitine supplementation to Faroese 3-MCCd patients. METHODS Blood and urine samples and muscle biopsies were collected from patients at inclusion and at 3 months. Eight patients received L-carnitine supplementation when recruited; five did not. Included patients who received supplementation were asked to stop L-carnitine, the others were asked to initiate L-carnitine supplementation during the study. Symptoms were determined by review of hospital medical records and questionnaires answered at baseline and after the intervention. RESULTS The prevalence of 3-MCCd in the Faroe Islands was 1:2,400, the highest reported worldwide. All patients were homozygous for the MCCC1 mutation c.1526delG. When not administered L-carnitine, the 3-MCCd patients (n = 13) had low plasma and muscle free carnitine levels, 6.9 (SD 1.4) μmol/L and 785 (SD 301) nmol/g wet weight, respectively. L-Carnitine supplementation increased muscle and plasma carnitine levels to a low-normal range, 25.5 (SD 10.9) μmol/L and 1,827 (SD 523) nmol/g wet weight, p < 0.01, respectively. Seven of the thirteen 3-MCCd subjects suffered from self-reported fatigue with some alleviation after L-carnitine supplementation. CONCLUSION 3-MCCd is common in the Faroe Islands. Some symptomatic 3-MCCd patients may benefit biochemically and clinically from L-carnitine supplementation, a more general recommendation cannot be given.