Latest research in football - week 25 - 2021

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 Seasonal training and match load and micro-cycle periodization in male Premier League academy soccer players

Reference: J Sports Sci. 2021 Mar 24;1-12.  doi: 10.1080/02640414.2021.1899610. Online ahead of print.

Authors: Marcus P Hannon, Nicholas M Coleman, Lloyd J F Parker, John McKeown, Viswanath B Unnithan, Graeme L Close, Barry Drust, James P Morton

Summary: We quantified on pitch external loading of English Premier League (EPL) academy soccer players (n=76; U12-U18 age groups) over an entire competitive season. Mean accumulative weekly duration and total distance, respectively, was similar in the U12 (329±29 min; 19.9±2.2 km), U13 (323±29 min; 20.0±2.0 km) and U14 (339±25 min; 21.7±2.0 km; P>0.05 for all comparisons) age-groups, though all teams were less than U15 (421±15 min; 26.2±2.1 km), U16 (427±20 min; 25.9±2.5 km) and U18 (398±30 min; 26.1±2.6 km) players (P<0.05 for all comparisons). Mean weekly high-speed running and sprint distance was not different between U12 (220±95 m and 6±9 m respectively), U13 (331±212 m and 6±27 m) and U14 (448±193 m and 21±29 m) age-groups (P>0.05 for all pairwise comparisons) though all squads were less than U15 (657±242 m and 49±98 m), U16 (749±152 m and 95±55 m) and U18 (979±254 m and 123±56 m) age-groups (P<0.05 for all pairwise comparisons). Data demonstrate that absolute weekly training volume in EPL academy soccer players increases throughout the academy pathway. Furthermore, although U16-U18 players are capable of achieving similar training and match volumes as previously reported in adult EPL players, they do not yet achieve the absolute intensities of adult EPL players



#2 Strength development according with age and position: a 10-year study of 570 soccer players

Reference: BMJ Open Sport Exerc Med. 2021 Mar 5;7(1):e000927. doi: 10.1136/bmjsem-2020-000927. eCollection 2021.

Authors: Robson Dias Scoz, Bruno Mazziotti Oliveira Alves, Ricardo Lima Burigo, Edgar Ramos Vieira, Luciano Maia Alves Ferreira, Rubens Alexandre da Silva, Rogerio Pessoto Hirata, Cesar Ferreira Amorim

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Summary: The purpose of this study was to compare the isokinetic peak torque profiles from the quadriceps and hamstrings muscles during concentric and eccentric contractions in elite Brazilian soccer players across different field positions and age categories. Our hypothesis was that soccer players from different field positions are subjected to different ageing-related effects on their isokinetic peak torque. This is a retrospective study based on professional elite-level soccer players between the years 2009 and 2019. It included 570 adult males who played for at least 5 years on first or second Brazilian divisions. Playing positions were divided as: goalkeepers, defenders, sidebacks, midfielders and forwards. Age categories were also divided as: G1 (17-20 years old), G2 (21-24 years old), G3 (25-28 years old), G4 (29-32 years old) and G5 (33 years old or more). The results indicate a moderate effect of age (F(4545)=8.197; p<0.001; η2=0.057) and a small effect of playing position (F(4545)=2.993; p<0.05; η2=0.021) on torque of concentric extensors; mainly from midfielders and goalkeepers with 29 years or more. Soccer players from different field positions are subjected to different ageing related effects on their muscular performance during their career special attention should be given to these players to avoid reduction in physical performance



#3 Effects of regular exercise on inflammatory biomarkers and lipid parameters in soccer players

Reference: J Immunoassay Immunochem. 2021 Mar 22;1-11.  doi: 10.1080/15321819.2021.1898421. 

Authors: Abdulmecit Afşin, Eren Bozyılan, Ramazan Asoğlu, Yusuf Hoşoğlu, Aykut Dündar

Summary: Since chronic dyslipidemia and inflammation play a major role in the etiopathogenesis of atherosclerotic plaque, we investigated the effects of a 7-week exercise on the serum lipid profile, plasma atherogenic index (PAI), and inflammatory biomarkers interleukin (IL), tumor necrosis factor (TNF)-α, and monocyte chemoattractant protein (MCP)-1 in male soccer players. Methods: The participants in this study were 22 healthy male soccer players aged 19-25 years. IL-1β, IL-6, IL-10, TNF-a, MCP-1, and lipid profile were recorded before and after the program. PAI was calculated as log (TG/HDL-C), where TG is triglyceride and HDL-C is high-density lipoprotein cholesterol. Results: There were significant decreases in post-exercise IL-6, TNF-α, and MCP-1 (for all, p< .05). Compared to the pretest values, there were significant decreases in posttest total cholesterol (TC), TGs, low-density lipoprotein (LDL), non- high-density lipoprotein cholesterol (non-HDL-C), and PAI (for all, p< .05). In contrast, HDL-C values increased after exercise (p< .001). After exercise training TC, TGs, LDL-C, non-HDL-C, and PAI decreased and HDL-C increased, indicating improvement in parameters of dyslipidemia. The decreases in IL-6, TNF-α, and MCP-1 suggest a decrease in systemic inflammation.



#4 Assessment of skeletal age in youth female soccer players: Agreement between Greulich-Pyle and Fels protocols

Reference: Am J Hum Biol. 2021 Mar 21;e23591.  doi: 10.1002/ajhb.23591.

Authors: Diogo V Martinho, Manuel J Coelho-E-Silva, João Valente-Dos-Santos, Cláudia Minderico, Tomás G Oliveira, Inês Rodrigues, Jorge Conde, Lauren B Sherar, Robert M Malina

Summary: The purpose of the study was to evaluate the agreement between the Fels and Greulich-Pyle methods for the assessment of skeletal age (SA) in female youth soccer players. The sample included 441 Portuguese players 10.08-16.73 years of age who regularly participated in organized and competitive soccer. Standardized radiographs of the left hand-wrist were obtained and analyzed by an experienced examiner. SA was estimated with the Fels and Greulich-Pyle (GP) methods. Differences between SA and chronological age (CA) were used to define skeletal maturity groups: late, average and early maturing. In addition to descriptive statistics, Cohen's kappa and Lin concordance correlation coefficients were used to evaluate agreement between methods. Intraindividual differences in SA based on the two methods varied between 0.10 to 1.47 years among age groups with larger mean differences at older ages. Agreement of maturity classifications between methods was 74% at younger ages (under-13: kappa = 0.48; under-14: kappa = 0.39; Lin CCC = 0.68) and declined with increasing CA (under-17: 19% agreement; kappa = 0.001; Lin CCC = 0.11). About 19% of the total sample was skeletally mature with the Fels method and an SA was not assigned; in contrast, no players were skeletally mature with the GP method.

GP SAs were systematically lower than Fels SAs among female soccer players. Intraindividual variability in SAs between methods was considerable. The findings highlight the impact of method on estimates of maturity status.



#5 Leveling the Playing Field: A New Proposed Method to Address Relative Age- and Maturity-Related Bias in Soccer

Reference: Front Sports Act Living. 2021 Mar 4;3:635379. doi: 10.3389/fspor.2021.635379. eCollection 2021.

Authors: Werner F Helsen, Martine Thomis, Janet L Starkes, Sander Vrijens, Gerrit Ooms, Calum MacMaster, Chris Towlson

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Summary: Despite various solutions proposed to solve the relative age effect (RAE), it is still a major problem confounding talent identification and selection processes. In the first phase, we sampled 302 under 7-21 academy soccer players from two Belgian professional soccer clubs to explore the potential of a new approach to solve the inequalities resulting from relative age- and maturity-related bias. This approach allocates players into four discrete quartile groups based on the midway point of their chronological and estimated developmental (ED) birth dates (calculated using the growth curves for stature of Belgian youth). With the use of chi square analyses, a RAE was found (p < 0.01) for the overall sample (Q1 = 41.4% vs. Q4 = 14.9%) that completely disappeared after reallocation (Q1 = 26.5%; Q2 = 21.9%; Q3 = 27.5%; Q4 = 24.2%). According to the new allocation method, the stature difference was reduced, on average, by 11.6 cm (from 24.0 ± 9.9 to 12.4 ± 3.4 cm, d = 1.57). Body mass difference between the two methods was 1.9 kg (20.1 ± 11.3-18.2 ± 13.1 kg, respectively, d = 0.15). The new method created a maximum chronological age difference of 1.9 vs. 0.8 years for the current method. With the use of this method, 47% of the players would be reallocated. Twenty-three percent would be moved up one age category, and 21% would be moved down. In the second phase, we also examined 80 UK academy soccer players to explore if reallocating players reduces the within-playing group variation of somatic and physical fitness characteristics. The percentage coefficient of variation (%CV) was reduced (0.2-10.1%) in 15 out of 20 metrics across U11-U16 age categories, with the U13 age category demonstrating the largest reductions (0.9-10.1%) in CV. The U12 and U13 age categories and associated reallocation groupings showed trivial to small (ES = 0.0-0.5) between-method differences and trivial to moderate (ES = 0.0-1.1) differences within the U14-U16 age categories. A reduction in RAE may lead to fewer dropouts and thus a larger player pool, which benefits, in turn, talent identification, selection, and development.



#6 Motor performance is not related to injury risk in growing elite-level male youth football players. A causal inference approach to injury risk assessment

Reference: J Sci Med Sport. 2021 Mar 16;S1440-2440(21)00056-6. doi: 10.1016/j.jsams.2021.03.004.

Authors: Nikki Rommers, Roland Rössler, Ian Shrier, Matthieu Lenoir, Erik Witvrouw, Eva D'Hondt, Evert Verhagen

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Summary: The aim was to identify the causal relation between growth velocity and injury in elite-level youth football players, and to assess the mediating effects of motor performance in this causal pathway. We measured the body height of 378 male elite-level football players of the U13 to U15 age categories three to four months before and at the start of the competitive season. At the start of the season, players also performed a motor performance test battery, including motor coordination (Körperkoordinationstest für Kinder), muscular performance (standing broad jump, counter movement jump), flexibility (sit and reach), and endurance measures (YoYo intermittent recovery test). Injuries were continuously registered by the academies' medical staff during the first two months of the season. Based on the causal directed acyclic graph (DAG) that identified our assumptions about causal relations between growth velocity (standardized to cm/y), injuries, and motor performance, the causal effect of growth velocity on injury was obtained by conditioning on maturity offset. We determined the natural indirect effects of growth velocity on injury mediated through motor performance. In total, 105 players sustained an injury. Odds ratios (OR) showed a 15% increase in injury risk per centimetre/year of growth velocity (1.15, 95%CI: 1.05-1.26). There was no causal effect of growth on injury through the motor performance mediated pathways (all ORs were close to 1.0 with narrow 95%CIs). Growth velocity is causally related to injury risk in elite-level youth football players, but motor performance does not mediate this relation.



#7 Space evaluation in football games via field weighting based on tracking data

Reference: Sci Rep. 2021 Mar 9;11(1):5509. doi: 10.1038/s41598-021-84939-7.

Authors: Takuma Narizuka, Yoshihiro Yamazaki, Kenta Takizawa

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Summary: In football game analysis, space evaluation is an important issue because it is directly related to the quality of ball passing or player formations. Previous studies have primarily focused on a field division approach wherein a field is divided into dominant regions in which a certain player can arrive prior to any other players. However, the field division approach is oversimplified because all locations within a region are regarded as uniform herein. The objective of the current study is to propose a fundamental framework for space evaluation based on field weighting. In particular, we employed the motion model and calculated a minimum arrival time [Formula: see text] for each player to all locations on the football field. Our main contribution is that two variables [Formula: see text] and [Formula: see text] corresponding to the minimum arrival time for offense and defense teams are considered; using [Formula: see text] and [Formula: see text], new orthogonal variables [Formula: see text] and [Formula: see text] are defined. In particular, based on real datasets comprising of data from 45 football games of the J1 League in 2018, we provide a detailed characterization of [Formula: see text] and [Formula: see text] in terms of ball passing. By using our method, we found that [Formula: see text] and [Formula: see text] represent the degree of safety for a pass made to [Formula: see text] at t and degree of sparsity of [Formula: see text] at t, respectively; the success probability of passes could be well-fitted using a sigmoid function. Moreover, a new type of field division approach and evaluation of ball passing just before shots using real game data are discussed.



#8 Physical performance and loading for six playing positions in elite female football: full-game, end-game, and peak periods

Reference: Scand J Med Sci Sports. 2021 Mar 22. doi: 10.1111/sms.13877. 

Authors: Jeppe Panduro, Georgios Ermidis, Line Røddik, Jeppe F Vigh-Larsen, Esben Elholm Madsen, Malte Nejst Larsen, Svein Arne Pettersen, Peter Krustrup, Morten B Randers

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Summary: The present study investigated the position-specific match demands and heart rate response of female elite footballers, with special focus on the full-game, end-game, and peak-intensity periods. In total, 217 match observations were performed in 94 players from all eight teams of the best Danish Women's League, that is, goalkeepers (GK, n = 10), central defenders (CD, n = 23), full-backs (FB, n = 18), central midfielders (CM, n = 28), external midfielders (EM, n = 18), and forwards (FW, n = 11). Positional data (GPS; 10 Hz Polar Team Pro) and HR responses were collected. HRmean and HRpeak were 87%-89% and 98%-99% of HRmax , for outfield players, with no positional differences. CM, EM, and FB covered 8%-14% greater (P < .001) match distances than CD. EM, FW, FB, and CM performed 40%-64% more (P < .05) high-speed running and 41%-95% more (P < .01) very-high-speed running (VHSR) than CD. From the first to the last 15-minute period, total distance, except for FW, number of VHSR, except FB, peak speed and sum of accelerations and sum of decelerations decreased (P < .05) for all outfield positions. In the most intense 5-minute period, EM, FB, and CM performed 25%-34% more (P < .01) HSR than CD, whereas EM, FW, and FB performed 36%-49% more (P < .01) VHSR than CD. In conclusion, competitive elite female matches impose high physical demands on all outfield playing positions, with high aerobic loading throughout matches and marked declines in high-speed running and intense accelerations and decelerations toward the end of games. Overall physical match demands are much lower for central defenders than for the other outfield playing positions, albeit this difference is minimized in peak-intensity periods.



#9 Brain Activation During the Observation of Real Soccer Game Situations Predict Creative Goalscoring

Reference: Soc Cogn Affect Neurosci. 2021 Mar 24;nsab035. doi: 10.1093/scan/nsab035. Online ahead of print.

Authors: Christian Rominger, Karl Koschutnig, Daniel Memmert, Ilona Papousek, Corinna M Perchtold-Stefan, Mathias Benedek, Andreas R Schwerdtfeger, Andreas Fink

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Summary: Creativity is an important source of success in soccer players. In order to be effective in soccer, unpredictable, sudden and at the same time creative (i.e., unique, original, and effective) ideas are required in situations with high time pressure. Accordingly, creative task performance in soccer should be primarily driven by rapid and automatic cognitive processes. This study investigated if functional patterns of brain activation during the observation/encoding of real soccer game situations can predict creative soccer task performance. A machine learning approach (multivariate pattern recognition) was applied in a sample of 35 experienced male soccer players. Results revealed that brain activation during the observation of the soccer scenes significantly predicted creative soccer task performance, while brain activation during the subsequent ideation/elaboration period did not. The identified brain network included areas such as the angular gyrus, the supramarginal gyrus, the occipital cortex, parts of the cerebellum and (left) supplementary motor areas, which are important for semantic information processing, memory retrieval, integration of sensory information, and motor-control. This finding suggests that early and presumably automatized neurocognitive processes, such as (implicit) knowledge about motor movements, and the rapid integration of information from different sources are important for creative task performance in soccer.



#10 Optimal Pretaper Phase on Physical Match Performance in Professional Soccer

Reference: Int J Sports Physiol Perform. 2021 Mar 23;1-7.  doi: 10.1123/ijspp.2020-0334. Online ahead of print.

Authors: Wassim Moalla, Mohamed Saifeddin Fessi, Sabeur Nouira, Alberto Mendez-Villanueva, Valter Di Salvo, Said Ahmaidi

Summary: The purpose was to investigate the optimal pretaper duration on match running performance in a professional soccer team. The training load was monitored during daily training sessions and matches during 2 seasons according to different periodization strategies. Matches' running distances were collected using match analysis system. The data were analyzed in 3 types of mesocycle blocks of 5 (M5), 4 (M4), and 3 weeks (M3), concludes all of them by 1 taper week. Significant decreases in the training load during the taper weeks compared to standard weeks were observed in 3 types of mesocycle blocks (d ≥ 5; P < .01). An increase in overall match running performance was observed in matches played after the taper weeks compared to matches played after the standard weeks during M4 for all speed ranges (d ≥ 1.3; P < .05). The increase was only observed in low-intensity running (d = 1.3; P < .04) and total distance, low-intensity running, and intense running (d ≥ 1.3; P < .05) in M5 and M3, respectively. Match running performance following the taper weeks between the 3 different mesocycle durations was significantly higher in M4 for the number of high-speed running, sprinting, and high-intensity running (P < .05). The greatest enhancement of match running performance was observed at M4 when the training load was decreased by approximately 18% during the tapering period. This study suggests that a period of 3 standard weeks of training followed by 1 taper week is the optimal taper strategy when compared to different pretaper durations.



#11 Eyes-Open Versus Eyes-Closed Somatosensory Motor Balance in Professional Soccer Players With Chronic Ankle Instability: A Case-Control Study

Reference: Orthop J Sports Med. 2021 Mar 8;9(3):2325967120983606. doi: 10.1177/2325967120983606. eCollection 2021 Mar.

Authors: David Rodríguez-Sanz, Antonio García-Sánchez, Ricardo Becerro-de-Bengoa-Vallejo, Eva María Martínez-Jiménez, César Calvo-Lobo, Josué Fernández-Carnero, Marta Elena Losa-Iglesias, Daniel López-López

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Summary: Chronic ankle instability (CAI) is a condition defined by certain structural and functional deficits in the ankle joint complex after acute ankle injury. These deficits include pathological joint laxity, impaired postural control, and decreased strength and neuromuscular control. The purpose was to compare an eyes-open versus an eyes-closed balance training protocol in professional soccer players with CAI. For this study, we evaluated 19 players from 2 professional soccer teams in Madrid, Spain, all of whom had CAI. Participants from both teams were randomly assigned to an eyes-open group (n = 9) or eyes-closed group (n = 10). All participants completed 4 weeks of a supervised exercise protocol consisting of 3 sessions per week. Members of both the eyes-open and eyes-closed groups performed the same exercise protocol in the same order of execution. At the end of the protocol, the participants were assessed for pain (visual analog scale), ankle dorsiflexion range of motion (weightbearing lunge test), dynamic stability (Star Excursion Balance Test), and fear of movement and reinjury (Tampa Scale for Kinesiophobia). We compared results both before and after balance training and between the eyes-open and eyes-closed balance training groups. Statistically significant differences were found for all of the assessed variables before and after balance training. No statistically significant differences were found between the eyes-closed and eyes-open groups on any variable. In the current study, eyes-closed balance training was not more effective than eyes-open balance training for CAI in professional soccer players.



#12 Quantification of training and match load in elite youth soccer players: a full-season study

Reference: J Sports Med Phys Fitness. 2021 Mar 26. doi: 10.23736/S0022-4707.21.12236-4. Online ahead of print.

Authors: Hadi Nobari, Amir Barjaste, Hamed Haghighi, Filipe M Clemente, Jorge Carlos-Vivas, Jorge Perez-Gomez

Summary: The present study aimed to quantify training and match load in elite young soccer players over the course of an entire season. Using a longitudinal design, session-rate of perceived exertion (s-RPE) and its metrics [weekly acute workload (wAW), acute to chronic workload ratio (wACWR), training monotony and training strain] were examined in twenty-one elite young soccer players (mean±standard deviation; age, 16.1±0.2 years; height, 176.8±5.6 cm; body mass, 67.3±5.7 kg; BMI, 21.5±1.4 kg/m2; VO2max, 47.6±3.8 during the whole season containing 4 meso-cycles: Pre-season (Pre-S), Earlyseason (Ear-S), Mid-season (Mid-S), and End-season (End-S). Repeated-measures analysis of variance examined variations in s-RPE load data across the 4 meso-cycles and 1-week of micro-cycle. Analyzing data revealed the End-S had a significant greater wAW compared to Early-S (p = 0.002, g = 0.96) and Mid-S (p < 0.001, g = 1.09). However, no differences between in-season periods were observed in wACWR (p = 0.524). The within-week variations revealed significant lower wAW in pre-match a day (MD-1) (p < 0.001), 1 day after match (MD+1) (p < 0.001) and 2 days after match (MD+2) (p < 0.001) compared to match day (MD) for overall team analysis. Additionally, analyses by playing position showed that fullbacks have a significant lower AW in MD+2 compared to MD (p < 0.029). The periodization of training load indicated variations across the whole season in young elite players. The weekly micro-cycle perceived load could be identified as follows; there are higher training loads on MD-3 and MD-2 which was similar to intensities experienced by players throughout the match play and, furthermore, lower overall WL on the MD+1 and MD+2 in order to ensure the optimal recovery of the players.



#13 Trends in Soccer-Related Ocular Injuries within the United States from 2010 through 2019

Reference: Semin Ophthalmol. 2021 Mar 30;1-6.  doi: 10.1080/08820538.2021.1909077. Online ahead of print.

Authors: Parth A Patel, Rhea Gopali, Anvith Reddy, Kajol K Patel

Summary: Soccer participation within the United States continues to increase, necessitating consideration of the various injuries that may occur. The present study analyzes trends in the incidence of ocular injuries secondary to soccer trauma, the associated mechanism, and related visual sequelae, and quantifies age- and sex-specific differences in the distributions of these variables. The Consumer Product Safety Commission's National Electronic Injury Surveillance System (NEISS) was queried for soccer-related ocular injuries from 2010 through 2019. Data exclusively focused on the globe were selected, and information regarding age, sex, specific diagnosis, mechanism of injury, and visual sequelae were acquired. Significance was calculated using the chi-squared test. 628 NEISS entries were evaluated, extrapolating to a national average incidence of approximately 1580 soccer-related ocular injuries per year. There were a relatively static number of events during the ten-year time period of study. The most common diagnoses were contusions or abrasions (36.1%); among records with a reported mechanism of injury, the most common was contact with the soccer ball (80.9%). Visual sequelae were noted in a significant minority of patients (15.4%). Patients ≤18 and males comprised the majority of visits (68.2% and 70.2%, respectively). Significant sex- and age-specific differences were observed in the distributions of diagnoses. There are serious visual consequences associated with soccer-related ocular injury. Despite the existence of eye protection, there remain no regulations requiring its consistent use. Therefore, among all parties involved (e.g., players, families, and physicians), there remains a need to increase education regarding the potential ocular dangers associated with the sport.



#14 Exploring Relationships Between Anthropometry, Body Composition, Maturation, and Selection for Competition: A Study in Youth Soccer Players

Reference: Front Physiol. 2021 Mar 11;12:651735. doi: 10.3389/fphys.2021.651735. eCollection 2021.

Authors: Filipe Manuel Clemente, Cain C T Clark, César Leão, Ana Filipa Silva, Ricardo Lima, Hugo Sarmento, António J Figueiredo, Thomas Rosemann, Beat Knechtle

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Summary: The purpose of this study was to analyze variations of selection for competition between late and early mature players and test the relationships between anthropometry, body composition, maturation, and selection for competition. Seventy-nine youth soccer players from under-11 to under-14 participated in this study, over 6 months. Body composition and maturity offset were estimated based on anthropometric data collected. Participants were also monitored for their number of matches as starters and time of play accrued in minutes. Minutes played had large correlation coefficients with maturity offset (r = 0.58), and leg length and sitting height interaction (r = 0.56). Multiple linear regression explained 35% of the variation in minutes played (p < 0.001, R 2 = 0.41, R 2 adjusted = 0.35, RMSE = 334.8), but only 12% of the variation in matches as starter (p = 0.04, R 2 = 0.21, R 2 adjusted = 0.12, RMSE = 5.47) between above and below the median of the maturity offset was accounted for, respectively. Although maturation may play a role in the minutes of play accrued and matches as starters in young, it is not necessarily determining. A significant amount of the variation in the minutes of play accrued of players can be accounted for when considering body composition and anthropometric data.



#15 One year of Football Fitness improves L1-L4 BMD, postural balance and muscle strength in women treated for breast cancer

Reference: Scand J Med Sci Sports. 2021 Apr 1.  doi: 10.1111/sms.13963.

Authors: Jacob Uth, Bjørn Fristrup, Victor Sørensen, Eva Wulff Helge, Maja Kjaergaard Christensen, Julie Boye Kjaergaard, Trine Kjeldgaard Møller, Jørn Wulff Helge, Niklas Rye Jørgensen , Mikael Rørth, Eva Soelberg Vadstrup, Peter Krustrup 

Summary: The purpose was to examine efficacy of 12 months Football Fitness offered twice per week on bone mineral density (BMD), bone turnover markers (BTM), postural balance, muscle strength and body composition in women treated for early-stage breast cancer (BC). Women treated for early-stage BC were randomised to Football Fitness (FFG, n=46) or control (CON, n=22) in a 2:1 ratio for 12 months, with assessments performed at baseline, 6 months and 12 months. Outcomes were total body-, lumbar spine- and proximal femur BMD, total body lean and fat mass, leg muscle strength, postural balance, and plasma amino-terminal propeptide of type 1 procollagen (P1NP), osteocalcin and C-terminal telopeptide of type 1 collagen (CTX). Intention-to-treat (ITT) analyses and per-protocol analyses (≥50% attendance in FFG) were performed using linear mixed models. Participants in FFG completing the 12-month intervention (n=33) attended 0.8 (SD=0.4) sessions per week. Intention to treat analysis of mean changes over 12 months showed significant differences in L1-L4 BMD (0.029 g/cm2 , 95%CI: 0.001 to 0.057), leg press strength (7.2 kg, 95%CI: 0.1 to 14.3) and postural balance (-4.3 n need of support, 95%CI: -8.0 to -0.7) favouring FFG compared to CON. In the per-protocol analyses, L1-L4 and trochanter major BMD were improved (p=0.012 and 0.030, respectively) in FFG compared to CON. No differences were observed between groups in BTMs in the ITT or per protocol analyses. One year of Football Fitness training may improve L1-L4 BMD, leg muscle strength and postural balance in women treated for early-stage breast cancer.


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