Latest research in football - week 34 - 2023

As previous literature updates, I have performed a PubCrawler search looking for football articles in NCBI Medline (PubMed) and GenBank databases. 


Following studies were retrieved for this week:

#1 Effects of the Timing of Carbohydrate Intake on Metabolism and Performance in Soccer Players

Reference: Nutrients. 2023 Aug 17;15(16):3610. doi: 10.3390/nu15163610.

Authors: Ki-Woong Noh, Jung-Hwan Oh, Sok Park

Summary: This study aims to provide information to improve the performance of athletes comparing the effects of carbohydrate-electrolyte intake before and during exercise on metabolism and performance in soccer players. The study had a single-blind cross-over design. Drust's protocol is a soccer-specific intermittent exercise test. The carbohydrate-electrolyte intake experiments were divided into three timings: first, pre-exercise; second, half-time; and third, mixed. Eight participants were included in the data analysis (age: 21.32 ± 1.19 years; BMI: 22.69 ± 1.91 kg/m2; height: 176.5 ± 7.52 cm; weight: 69.5 ± 9.18 kg; Vmax: 16.75 0.71 km/h). The results of the mixed test showed a significantly lower respiratory exchange ratio than those of the placebo and half-time tests (p < 0.05). The mixed test showed significantly more fat oxidation than the half-time test (p < 0.05). The running times are placebo (422.13 ± 133.44 s) and mixed (677.38 ± 217.75 s), and the distances are placebo (1577.25 ± 517.02 m) and mixed (2530.00 ± 832.71 m) (p < 0.05). The mixed test showed a significantly lower rating of perceived exertion than the placebo test (p < 0.05). Carbohydrate oxidation and heart rate showed no significant differences between the experiments (p > 0.05). The exercise protocol in this study showed the metabolic response of soccer players to intermittent high-intensity exercise and subsequent endurance exercise. In conclusion, it can be seen that the intake of carbohydrate-electrolytes improves the performance of soccer players, and the effect varies depending on the timing of carbohydrate-electrolyte intake.



#2 Walking football for Health - physiological response to playing and characteristics of the players

Reference: Sci Med Footb. 2023 Aug 26;1-8. doi: 10.1080/24733938.2023.2249426. Online ahead of print.

Authors: Helena Andersson, Andreas Caspers, Manne Godhe, Torbjörn Helge, Julia Eriksen, Dan Fransson, Mats Börjesson, Elin Ekblom-Bak

Summary: Walking Football (WF) is one type of recreational football increasing in popularity, targeting older adults. Further knowledge on the intensity and physical workload of WF, characteristics of the players, the social context, and reasons for playing WF is needed. Thus, the aim of the study was to characterize the individuals that regularly play WF and their experience of WF, and the physiological characteristics of the sport. Sixty-three players from three clubs taking part in organised WF in Sweden were included. The players participated in up to four WF-games and underwent performance tests and answered a questionnaire. The participants mean age was 70.9 years, ranging from 63 to 85 years with 71% (n = 27) of the men and 68% (n = 13) of the women having a BMI > 25. Fifty-one percent (n = 27) of the players had hypertension, and 73% (n = 39) regularly used prescription drugs due to illness. During WF, the players covered on average 2,409 m (2,509 m for men and 2,205 m for women, p = .001). Expressed in percentage of their age-estimated maximal heart rate, mean heart rate represented 80 ± 9 and 80 ± 8% of max for men, and 78 ± 9 and 79 ± 9% of max for women in the first and second halves, respectively, hence WF can be considered a moderate intensity activity for older adults. The main reason for WF participation was to socialize. WF includes a considerable number of accelerations and decelerations, making it more energetically and mechanically demanding than walking.



#3 Effect of High Intensity Interval Training Under Mask on Forced Vital Capacity in Football Players

Reference: Int J Exerc Sci. 2023 May 1;16(6):576-586. eCollection 2023.

Authors: Bumrung Neranoch, Manimmanakorn Apiwan, Traiperm Natthapon

Summary: The purpose of the study was to investigate the effect of high interval training (HIIT) under mask on forced vital capacity in football players. Fourteen male football players (age 20 ± 2 years) were randomized into the without mask group (CON) or with the 2 difference mask groups [Surgical mask (SM), FFP2 mask (FM)]. HIIT program were implemented six movements in each session three times per week. Body composition, forced vital capacity and percutaneous oxygen saturation test were taken before and after 4 weeks intervention. The results show that forced vital capacity was statistically significant increased with both types of masks (SM: 5.68 ± 1.07 L; FM: 5.26 ± 0.86 L; CON: 4.66 ± 0.48 L, p < 0.01). Additionally, not significant difference in percutaneous oxygen saturation (SpO2) was found, and fat free mass (SM: 54.45 ± 4.01 kg; FM: 57.08 ± 4.38kg; CON: 58.34 ± 1.81 kg, p<0.01) were statistically significant changed with SM and CON but not FM. In conclusion, wearing surgical masks and FFP2 face mask during high-intensity interval exercise showed certain positive impacts on cardiopulmonary function. This short-term high-intensity interval training can be used to improve forced vital capacity performance among football players. This finding can be applied to develop the strength of breathing muscles in the future.



#4 The effect of bio-electro-magnetic-energy-regulation therapy on sleep duration and sleep quality among elite players in Norwegian women's football

Reference: Front Psychol. 2023 Aug 8;14:1230281. doi: 10.3389/fpsyg.2023.1230281. eCollection 2023.

Authors: Frode Moen, Svein Arne Pettersen, Kine Gjertsås, Marte Vatn, Martijn Ravenhorst, Atle Kvålsvoll, Kristian Hovde Liland, Ellen F Mosleth

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Summary: The current study investigated if physical loads peak on game days and if Bio-Electro-Magnetic-Energy-Regulation (BEMER) therapy is affecting sleep duration and sleep quality on nights related to game nights among elite players in Norwegian women's elite football. The sample included 21 female football players from an elite top series club with a mean age of ~24 years (± 2.8). Sleep was measured every day over a period of 273 consecutive days with a Somnofy sleep monitor based on ultra-wideband (IR-UWB) pulse radar and Doppler technology. The current study was conducted as a quasi-experiment, where each player was their own control based on a control period that lasted for 3 months, and an experimental period that lasted for 5 months. Accordantly, the time each player spent with BEMER therapy was used as a control variable. Multivariate analyses of variance using FFMANOVA and univariate ANOVA with False Discovery Rate adjusted p-values show that physical performance (total distance, distance per minute, sprint meters >22.5 kmh, accelerations and decelerations) significantly peak on game day compared with ordinary training days and days related to game days. The results also show that sleep quantity and quality are significantly reduced on game night, which indicate disturbed sleep caused by the peak in physical load. Most sleep variables significantly increased in the experiment period, where BEMER therapy was used, compared to the control period before the introduction of BEMER therapy. Further, the analyses show that players who spent BEMER therapy >440 h had the most positive effects on their sleep, and that these effects were significantly compared to the players who used BEMER therapy <440 h. The findings are discussed based on the function of sleep and the different sleep stages have on recovery.



#5 Effective playing time affects technical-tactical and physical parameters in football

Reference: Front Sports Act Living. 2023 Aug 8;5:1229595. doi: 10.3389/fspor.2023.1229595. eCollection 2023.

Authors: Óscar Tojo, Konstantinos Spyrou, João Teixeira, Paulo Pereira, João Brito

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Summary: Effective playing time has been debated as a topic of major concern in football. Thus, the current experimental study aimed to investigate the effects of effective playing time on technical-tactical and physical match parameters in football. One hundred and seventy-nine male highly trained football players (aged 27.9 ± 5.1 years) from twelve teams performed two different match-play conditions: 45 min of match-play without stopping the chronometer (T45), and 30 min of match-play by stopping the chronometer every time the ball was out-of-play (T30). T30 presented a significantly higher total time (49:30 vs. 45:00 min; p = <.001; ES = 0.76), effective playing time (28:70 vs. 26:80 min; p = <.001; ES = 0.62), and stopped time (20:60 vs. 18:20 min; p = 0.003; ES = 0.38) compared to T45. Total ball possession (54.4% vs. 45.6%; p = 0.002) and 1/3 ball possession (55.3% vs. 44.7%; p = 0.018) was higher in T30 condition when compared to T45. Regarding match external load, total distance covered (4,899 vs. 4,481 m; p = <.001; ES = 0.71), moderate-speed running (607 vs. 557 m; p = 0.002; ES = 0.26) and high-speed running (202 vs. 170 m; p = <.001; ES = 0.33), high-speed activities (284 vs. 245 m; p = 0.003; ES = 0.24), accelerations (27 vs. 24; p = <.001; ES = 0.32), and decelerations (31 vs. 28; p = 0.005; ES = 0.26) were higher in T30 compared to T45. In conclusion, these findings suggest that higher effective playing time may affect technical-tactical and physical parameters during football games.



#6 Association between physical demands, skin temperature and wellbeing status in elite football players

Reference: Sci Rep. 2023 Aug 23;13(1):13780. doi: 10.1038/s41598-023-40396-y.

Authors: Carlos Majano, Jorge Garcia-Unanue, Ismael Fernández-Cuevas, Víctor Escamilla-Galindo, Antonio Alonso-Callejo, Javier Sanchez-Sanchez, Leonor Gallardo, Jose Luis Felipe

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Summary: The demanding nature of elite football requires players to be closely monitored to ensure optimal performance and minimize injury risk. This study aimed to evaluate the relationship between physical demands, skin temperature, and well-being status in 30 elite football players over a 12-week competitive period. Thermography assessments, weekly Well-being questionnaires, and daily training and match load recordings were used to gather data. Results indicated that along the microcycles there was a decrease in high-intensity accelerations and decelerations distance completed, while maintaining other high-intensity actions. Furthermore, it was found that high-intensity movements contribute to the generation of thermal asymmetries in the thighs; the adductor thermal asymmetry showed a positive relationship with stress and muscle soreness, the knee thermal asymmetry had a positive relationship with fatigue and a negative relationship with rest and quality of rest, and finally the hamstrings muscles exhibited significant differences between the thermal asymmetry groups, with the high asymmetry completing less high intensity actions than the low asymmetry group. In conclusion, this study highlights the interconnections between physical demands, skin temperature, and well-being in elite football players and provides valuable insights for coaches and trainers in their efforts to optimize performance and health.



#7 Skinfold thickness in elite male professional football players: changes across 3 seasons including a COVID-19 lockdown period

Reference: Sci Med Footb. 2023 Aug 22;1-8. doi: 10.1080/24733938.2023.2248062. Online ahead of print.

Authors: Craig Flannigan, Mark Robinson, Nidia Rodriguez-Sanchez, Barry Drust, Ruairidh McGregor, Stuart Galloway

Summary: This study investigates variations in skinfold thickness in a European professional football team within and across multiple seasons, including before and after COVID-19 restrictions. Skinfold thickness was measured in 49 male players on 32 occasions across three seasons (2018/19, 2019/20 and 2020/21). Intra- and inter-seasonal trends were examined by comparing values for the sum of eight skinfolds (sum8) at key time points using linear mixed models. In each season, the largest differences in sum8 occurred after the preseason period. These differences ranged from a mean difference (Mdiff) of -11.0 mm (p < 0.001) in 2018/19 to -4.8 mm (p < 0.001) in 2020/21. Increases in sum8 occurred after each off-season; however, the increase after the off-season before the 2020/21 season (which included the COVID-19 lockdown period) was the lowest in magnitude and was not statistically significant (Mdiff = 2.9 mm, p = 0.06). Changes occurring in sum8 between the start and end of the competitive season did not follow a consistent pattern and were generally smaller in magnitude than the changes between other seasonal time points. Despite the notable heterogeneity in sum8 between players, changes within players generally followed a similar pattern between the different seasonal timepoints. In summary, changes in skinfold thickness were predominantly related to off-season and 'preparation for competition' periods. Increases in skinfold thickness can be mitigated during extended remote training periods with appropriate training and nutritional strategies.



#8 Competitive season effects on polyunsaturated fatty acid content in erythrocyte membranes of female football players

Reference: J Int Soc Sports Nutr. 2023 Dec;20(1):2245386. doi: 10.1080/15502783.2023.2245386.

Authors: Nere Peña, Javier Amézaga, Gerard Marrugat, Alba Landaluce, Toscana Viar, Julen Arce, Jon Larruskain, Josean Lekue, Carla Ferreri, José María Ordovás, Itziar Tueros

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Summary: An optimal and correctly balanced metabolic status is essential to improve sports performance in athletes. Recent advances in omic tools, such as the lipid profile of the mature erythrocyte membranes (LPMEM), allow to have a comprehensive vision of the nutritional and metabolic status of these individuals to provide personalized recommendations for nutrients, specifically, the essential omega-3 and omega-6 fatty acids, individuating deficiencies/unbalances that can arise from both habitual diet and sportive activity. This work aimed to study the LPMEM in professional female football players during the football season for the first time and compare it with those defined as optimal values for the general population and a control group. An observational study was carried out on female football players from the Athletic Club (Bilbao) playing in the first division of the Spanish league. Blood samples were collected at three points: at the beginning, mid-season, and end of the season for three consecutive seasons (2019-2020, 2020-2021, and 2021-2022), providing a total of 160 samples from 40 women. The LPMEM analysis was obtained by GC-FID by published method and correlated to other individual data, such as blood biochemical parameters, body composition, and age. We observed a significant increase in docosahexaenoic acid (DHA) (p 0.048) and total polyunsaturated fatty acid (PUFA) (p 0.021) in the first season. In the second season, we observed a buildup in the membrane arachidonic acid (AA) (p < .001) and PUFA (p < .001) contents when high training accumulated. In comparison with the benchmark of average population values, 69% of the football players showed lower levels of omega-6 dihomo-γ-linolenic acid (DGLA), whereas 88%, 44%, and 81% of the participants showed increased values of AA, eicosapentaenoic acid (EPA), and the ratio of saturated and monounsaturated fatty acids (SFA/MUFA), respectively. Regarding relationships between blood biochemical parameters, body composition, and age with LPMEM, we observed some mild negative correlations, such as AA and SFA/MUFA ratio with vitamin D levels (coefficient = -0.34 p = .0019 and coefficient = -.25 p = .042); DGLA with urea and cortisol (coefficient = -0.27 p < .006 and coefficient = .28 p < .0028) and AA with age (coefficient = -0.33 p < .001). In conclusion, relevant variations in several fatty acids of the membrane fatty acid profile of elite female football players were observed during the competitive season and, in comparison with the general population, increased PUFA contents were confirmed, as reported in other sportive activities, together with the new aspect of DGLA diminution, an omega-6 involved in immune and anti-inflammatory responses. Our results highlight membrane lipidomics as a tool to ascertain the molecular profile of elite female football players with a potential application for future personalized nutritional strategies (diet and supplementation) to address unbalances created during the competitive season.



#9 Age-Related Reference Intervals for Physical Performance Test Outcomes Relevant to Male Youth Middle Eastern Football Players

Reference: Int J Sports Physiol Perform. 2023 Aug 21;1-13. doi: 10.1123/ijspp.2023-0145. Online ahead of print.

Authors: Lorenzo Lolli, Warren Gregson, Daniele Bonanno, Sami Kuitunen, Valter Di Salvo

Summary: The purpose was to develop age-specific reference intervals for physical performance test outcomes relevant to male youth Middle Eastern football players. We analyzed mixed-longitudinal data (observations range: 1751-1943 assessments) from a sample of 441 male youth outfield football players (chronological age range: 11.7-18.4 y) as part of the Qatar Football Association and Aspire Academy development program over 14 competitive seasons. Semiparametric generalized additive models for location, scale, and shape estimated age-specific reference centiles for 10-m sprinting, 40-m sprinting, countermovement jump height, and maximal aerobic speed variables. The estimated reference intervals indicated that the distribution of the physical performance test scores increased monotonically and nonlinearly with advancing chronological age for sprinting and countermovement jump outcome measures, reaching a plateau after 16 years common to each of these performance variables. The maximal aerobic speed median score increased substantially until ∼14.5 years, with the nonlinear trend flattening off toward relatively older chronological ages. We developed age-related reference intervals for physical performance test outcomes relevant to youth Qatari football players. Country-wide age-specific reference intervals can assist in the longitudinal tracking of the individual players' progress over time against benchmark values derived from the reference population.



#10 Stakeholder governance and sustainability in football: A bibliometric analysis

Reference: Heliyon. 2023 Aug 4;9(8):e18942. doi: 10.1016/j.heliyon.2023.e18942. eCollection 2023 Aug.

Authors: Juan Alejandro Hernández-Hernández, Abraham Londoño-Pineda, Jose Alejandro Cano, Rodrigo Gómez-Montoya

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Summary: This study presents a bibliometric analysis of stakeholder governance and sustainability in football. The PRISMA statement and the main techniques from the existing bibliometric analysis toolbox are applied to guide the research. The analysis includes 127 documents from Scopus and WoS, covering the period from 2007 to mid-2023, to examine the performance analysis and science mapping of the subject over time. The study's key findings highlight publication-related metrics, citation-and-publication-related metrics, co-authorship analysis, and co-word analysis. The analysis also identifies research gaps, including the need to explore barriers to stakeholder governance in football, the application of stakeholder pressure frameworks in football clubs, the examination of mimetic and normative pressures in the context of sustainability and governance in football, and the involvement of stakeholders and football institutions in collaborative efforts to enhance the effectiveness and impact of sustainability initiatives.



#11 Association between Dietary Consumption of Meals Combining the Five Food Groups and Stage of Change in the Fifth and Sixth Elementary and Junior High School-Aged Children in Sports Clubs: A Cross-Sectional Research at Soccer Clubs

Reference: J Nutr Sci Vitaminol (Tokyo). 2023;69(4):243-250. doi: 10.3177/jnsv.69.243.

Authors: Satoko Ozawa, Shuko Tanakadate, Chinatsu Watanabe, Naomi Omi

Summary: This study examined the relationship between dietary intake and stage of change for "combining the five food groups" (grains, fish and meat, vegetables, milk, and fruits) and examined characteristics of dietary intake by stage of change among fifth and sixth graders in elementary and junior high school in sports clubs. The 395 children who completed the self-reported dietary consumption form and questionnaire on stage of change for combining the five food groups were analyzed. Logistic regression analysis was conducted to analyze the relationship between intake of the combined five food groups and stage of change, with frequency of the five meals as dependent variable and stage of change as independent variable. Compared to the precontemplation stage, action (A) and maintenance stages (M) were associated with a higher frequency of the number of meals combining the five food groups (A, stage adjusted odds ratio [AOR]: 5.11, 95% confidence interval (CI): 1.50-17.36, p=0.009; M, AOR: 3.84, 95%CI: 1.58-9.33, p=0.003). In breakfast, the number of and each of combining the five food groups meal, and in dinner, the number of combining the five food groups meal, vegetable dishes and fruits were significantly higher in the A and M than in the pre-action stages. These findings suggest that the number of times meals combining the five food groups are consumed was associated with stage of change while breakfast and dinner showed differences in meal consumption between stages in the fifth and sixth grades elementary and junior high school students belonging to sports clubs.



#12 Inconsistent Effect of Psychometric-Scale Familiarization on the Relationship Between Ratings of Perceived Exertion and External Load Measures in Elite Youth Soccer Players

Reference: Int J Sports Physiol Perform. 2023 Aug 30;1-9. doi: 10.1123/ijspp.2022-0428. Online ahead of print.

Authors: Efthymios Kyprianou, Lorenzo Lolli, Matthew Weston, Warren Gregson

Summary: The aim was to examine the moderating effect of familiarization on the relationship between external load and ratings of perceived exertion (RPEs) in elite youth soccer players. Thirty-five elite male youth soccer players were monitored over a 31-week period. Players had no previous experience using the centiMax scale (arbitrary units [AU]). The final sample included familiarized (blackness test; n = 20) and nonfamiliarized players (n = 15) with the Borg centiMax scale. Players recorded a global RPE and differential RPEs (dRPE) for breathlessness (RPE-B) and leg-muscle exertion (RPE-L) 15 to 30 minutes following training sessions and competitive matches. Separate multivariable-adjusted random-effects generalized additive models with restricted maximum likelihood quantified familiarization versus no-familiarization differences in actual perceived exertion score (in AU) by number of accelerations, decelerations, and high-speed running distance (in meters) as predictor variables, respectively. Players improved their blackness test score from 39% to 78%. For explorations by number of accelerations, familiarization effects were not practically relevant for the RPE and RPE-B variables. The width and sign of the effects for the RPE-L variable at 30 efforts of 10 AU (95% CI, 4-16 AU) suggested that scores were lower for players who underwent familiarization versus players who did not. Familiarization effects were not practically relevant for any RPE variable irrespective of the number of deceleration efforts and high-speed running distance covered. Improved performance on the blackness test did not have a moderating effect on the relationship between proxy measures of external load and RPEs.



#13 Preece-Baines 1 model validation for cross-sectional data in male soccer players according to maturity status

Reference: Am J Hum Biol. 2023 Aug 29;e23980. doi: 10.1002/ajhb.23980. Online ahead of print.

Authors: Luis Alberto Flores Olivares, Maria Isabel Caldas Januário Fragoso

Summary: The aim of the present study was to compare the Preece-Baines 1 (PB1) model fit between longitudinal and cross-sectional data in male soccer players and to adjust the height growth curve by maturity status. A final sample of 57 male Portuguese soccer players from professional soccer academies was included. Longitudinal height records were measured between 8 and 17 times in each subject from 2-8 years to 14-17 years. Additionally, longitudinal height records were used as cross-sectional data along with 1087 cross-sectional height records taken from 602 Portuguese soccer players. Skeletal age was estimated by Tanner-Whitehouse III method from a left hand-wrist radiograph. Age at peak height velocity (PHV) was estimated by PB1 model for longitudinal and cross-sectional data and by maturity status. No significant differences were found between all the longitudinal estimates of 57 players and the random cross-sectional samples for, S1 parameter and for growth velocity at PHV, at TO, and for age at PHV. The age at PHV in early, on-time, and late maturers were 12.26, 12.9, and 13.58 years, respectively. PB1 adjusted the height growth of Portuguese male soccer players from cross-sectional data, obtaining an estimate PHV very similar to that found from longitudinal data. A maturity time difference of ≈0.6 years was found between the age at PHV of on-time, early, and on-time and late maturity state.



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