Latest research in football - week 7 - 2016

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 Periodization Training Focused On Technical-Tactical Ability In Young Soccer Players Positively Affects Biochemical Markers And Game Performance
Reference: J Strength Cond Res. 2016 Feb 13. [Epub ahead of print]
Authors: Leal de Queiroz Thomaz de Aquino R, Cruz Gonçalves LG, Palucci Vieira LH, de Paula Oliveira L, Alves GF, Pereira Santiago PR, Puggina EF
Summary: The aim of this study was to investigate the effects of 22 weeks of periodized training, with an emphasis on technical-tactical ability, on indirect markers of muscle damage and the on-field performance of young soccer players. Fifteen players (age 15.4 ± 0.2 years, height 172.8 ± 3.6 cm; body mass 61.9 ± 2.9 kg; % fat 11.7 ± 1.6; VO2max 48.67 ± 3.24 underwent four stages of evaluation: pre-preparatory stage - T0; post-preparatory stage - T1; post-competitive stage I - T2 and; post-competitive stage II - T3. The plasmatic activity of creatine kinase (CK) and lactate dehydrogenase (LDH) were evaluated as well as the on-field performance (movement patterns, tactical variables). Regarding the plasmatic activity of CK and LDH, there was a significant reduction (p ≤ 0.05) throughout the periodization training (T0: ~ 350 U/L; T3: ~ 150 U/L). Significant increases were observed (p ≤ 0.05) in the intensity of the game, high intensity activities (T0: ~ 22 %; T3: ~ 27%), maximum speed (T0: ~ 30 km.h; T3: ~ 34 km.h) and tactical performance, team surface area (T0: ~ 515 m; T3: ~ 683 m) and spread (T0: ~ 130 m; T3: ~ 148 m). In addition, we found significant inverse correlations between the percentage variation of T0 to T3 in CK and LDH activities with percentage variation in high intensity running (r = -0.85; p < 0.05 and r = -0.84; p < 0.01 respectively) and high intensity activities (r = -0.71 and r = -0.70; p < 0.05 respectively) during the matches. We concluded that there was reduced activity in biochemical markers related to muscle damage, as well as increases in-game high-intensity performance and the tactical performance of the study participants. Furthermore, players who showed greater reduction in plasma activity of CK and LDH also obtained greater increases in-game high-intensity performance along the periodization. These results may contribute to the expansion and future consolidation of the knowledge of coaches and sport scientists to develop effective methodologies for training in soccer.

#2 Effects of 6-month soccer and traditional physical activity programmes on body composition, cardiometabolic risk factors, inflammatory, oxidative stress markers and cardiorespiratory fitness in obese boys
Reference: J Sports Sci. 2016 Feb 18:1-8. [Epub ahead of print]
Authors: Seabra A, Katzmarzyk P, Carvalho MJ, Seabra A, Coelho-E-Silva M, Abreu S, Vale S, Póvoas S, Nascimento H, Belo L, Torres S, Oliveira J, Mota J, Santos-Silva A, Rêgo C, Malina RM
Summary: Physical activity is important in obesity prevention, but the effectiveness of different physical activity modalities remains to be determined among children. The main purpose of this study was to compare the effects of a 6-month soccer programme and a traditional physical activity programme on changes in body composition, cardiometabolic risk factors, inflammatory and oxidative markers, cardiorespiratory fitness and perceived psychological status in obese boys. Eighty-eight boys (8-12 years; BMI > +2 standard deviations of WHO reference values) participated in one of three groups: soccer, traditional activity and control. Soccer and traditional activity programmes involved 3 sessions per week for 60-90 min at an average intensity of 70-80% of maximal heart rate. Control group participated in activities of normal daily living. All boys participated in school physical education, two sessions per week of 45-90-min. Measurements were taken at baseline and after 6 months, and included body size and composition, cardiometabolic risk factors, inflammatory and oxidative markers, cardiorespiratory fitness and perceived psychological status. Physical activity and dietary intake were assessed before and immediately following the intervention. The three groups had similar characteristics at baseline. After 6 months, both intervention groups had significantly lower relative fatness (% fat), waist circumference and total cholesterol, and higher cardiorespiratory fitness, self-esteem, perceived physical competence and attraction to physical activity compared with control group. In conclusion, physical activity interventions over 6 months positively influenced several indicators of health status among obese boys. The results also suggested that soccer has the potential as an effective tool for the prevention and reduction of childhood obesity and associated consequences.

#3 Safety of third-generation artificial turf in male elite professional soccer players in Italian major league
Reference: Scand J Med Sci Sports. 2016 Feb 16. doi: 10.1111/sms.12654. [Epub ahead of print]
Authors: Lanzetti RM, Ciompi A, Lupariello D, Guzzini M, De Carli A, Ferretti A
Summary: Our hypothesis is that there are no difference in the injury incidence on artificial turf and natural grass. During the 2011/2012 season, we recorded injuries which occurred to two Italian stadiums equipped with third-generation artificial turf during 36 games (391 players). Data were compared with the injuries which occurred in the same season in two stadiums equipped with natural grass (372 players). We recorded 43 injuries during the playing time (16.7 per 1000 h). About 23 (18.1 per 1000 h) injuries occurred on artificial turf, while 20 (15.2 per 1000 h) on the natural grass with no statistical differences P > 0.05. We recorded 10 (7.87 per 1000 h) contact and 13 (10.23 per 1000 h) non-contact injuries on artificial turf, while 5 (3.8 per 1000 h) contact and 15 (11.4 per 1000 h) non-contact injuries on natural grass P > 0.05. The overall relative risk was 1.15; 95% CI: 0.64-2.07). Our study demonstrates a substantial equivalence in injury risk on natural grass and artificial turf in elite professional soccer athletes during official matches.

#4 Adaptations to Speed Endurance Training in Highly Trained Soccer Players
Reference: Med Sci Sports Exerc. 2016 Feb 16. [Epub ahead of print]
Authors: Nyberg M, Fiorenza M, Lund A, Christensen M, Rømer T, Piil P, Hostrup M, Christensen PM, Holbek S, Ravnholt T, Gunnarsson TP, Bangsbo J
Summary: The present study examined whether a period of additional speed endurance training would improve intense intermittent exercise performance in highly trained soccer players during the season and whether the training changed aerobic metabolism and the level of oxidative enzymes in type I and II muscle fibers. During the last nine weeks of the season, thirteen semi-professional soccer players performed additional speed endurance training sessions consisting of 2-3 sets of 8 - 10 repetitions of 30 m sprints with 10 s of passive recovery (SET). Before and after SET, subjects completed a double-step exercise protocol that included transitions from standing to moderate-intensity running (∼75% of maximal heart rate (HRmax)) followed by transitions from moderate to high-intensity running (∼90% HRmax) in which pulmonary oxygen uptake (V˙O2) was determined. In addition, the Yo-Yo Intermittent Recovery Test level 1 (YYIRT-1) was performed and a muscle biopsy was obtained at rest. YYIRT-1 performance was 11.6±6.4% (mean±SD) better (2803±330 vs. 3127±383 m, P<0.05) after compared to before SET. In the transition from standing to moderate-intensity running, phase II pulmonary V˙O2 kinetics was 11.4±16.5% faster (P<0.05) and running economy at this intensity was 2.3±3.0% better (P<0.05). These improvements were apparent despite the content of muscle proteins regulating oxidative metabolism (HAD, COX IV and OXPHOS) and capillarization were reduced (P<0.05). The content of HAD and CS in type I and II fibers did not change. In highly trained soccer players, additional speed endurance training is associated with an improved ability to perform repeated high-intensity work. To what extent the training-induced changes in V˙O2 kinetics and mechanical efficiency in type I fibers caused the improvement in performance warrants further investigation.

#5 The Effects of 52 Weeks of Soccer or Resistance Training on Body Composition and Muscle Function in +65-Year-Old Healthy Males
Reference: PLoS ONE 11(2): e0148236. doi:10.1371/journal. pone.0148236
Authors: Andersen TR, Schmidt JF, Pedersen MT, Krustrup P, Bangsbo J
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Summary: The effects of 52 weeks of soccer or resistance training were investigated in untrained elderly men. The subjects aged 68.1±2.1 yrs were randomised into a soccer (SG; n = 9), a resistance (RG; n = 9) and a control group (CG; n = 8). The subjects in SG and RG, respectively, trained 1.7±0.3 and 1.8±0.3 times weekly on average during the intervention period. Muscle function and body composition were determined before and after 16 and 52 weeks of the intervention period. In SG, BMI was reduced by 1.5% and 3.0% (p<0.05) after 16 and 52 weeks, respectively, unchanged in RG and 2% higher (p<0.05) in CG after 52 weeks of the intervention period. In SG, the response to a glucose tolerance test was 16% lower (p<0.05) after 16 wks, but not after 52 wks, compared to before the intervention period, and unchanged in RG and CG. In SG, superoxide dismutase-2 expression was 59% higher (p<0.05) after 52 wks compared to before the intervention period, and unchanged in RG and CG. In RG, upper body lean mass was 3 and 2% higher (p<0.05) after 16 and 52 wks, respectively, compared to before the intervention period, and unchanged in SG and CG. In RG, Akt-2 expression increased by 28% (p<0.01) and follistatin expression decreased by 38% (p<0.05) during the 52-wk intervention period, and was unchanged in SG and CG. Thus, long-term soccer training reduces BMI and improves anti-oxidative capacity, while long-term resistance training impacts muscle protein enzyme expression and increases lean body mass in elderly men.

#6 Contrasting effects of a mixed-methods high-intensity interval training intervention in girl football players
Reference: J Sports Sci. 2016 Feb 16:1-8. [Epub ahead of print]
Authors: Wright MD, Hurst C, Taylor JM
Summary: Little is known about the responses of girl athletes to training interventions throughout maturation. This study evaluated group and individual responses to an 8-week, mixed-methods, high-intensity interval training (HIIT) programme in girl football players. Thirty-seven players (age 13.4 ± 1.5 years) were tested for 20-m speed, repeated-sprint ability, change-of-direction speed and level 1 yo-yo intermittent recovery (YYIR). Players were subcategorised into before-, at- and after-PHV (peak height velocity) based on maturity offset. Very likely moderate (25%; ±90% confidence limits = 9.2) improvements occurred in YYIR, but data were unclear in players before-PHV with moderate individual differences in response. Decrements in repeated-sprint ability were most likely very large (6.5%; ±3.2) before-PHV, and likely moderate (1.7%; ±1.0) at-PHV. Data were unclear after-PHV. A very likely moderate (2.7%; ±1.0) decrement occurred in change-of-direction speed at-PHV while there was a very likely increase (-2.4%; ±1.3) in after-PHV players. Possibly small (-1.1%; ±1.4) improvements in 20-m speed occurred before-PHV but the effect was otherwise unclear with moderate to large individual differences. These data reflect specific responses to training interventions in girls of different biological maturity, while highlighting individual responses to HIIT interventions. This can assist practitioners in providing effective training prescription.

#7 Ossification of the Interosseous Membrane of the Leg in a Football Player: Case Report and Review of the Literature
Reference: Case Rep Orthop. 2016;2016:2930324. doi: 10.1155/2016/2930324. Epub 2016 Jan 6.
Authors: Postacchini R, Carbone S, Mastantuono M, Della Rocca C, Postacchini F
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Summary: Introduction. We report a case of ossification of the interosseous membrane (OIM) of the leg in a football player who had no history of severe local traumas. A review of the literature of the OIM of the leg in athletes was also carried out. Case Report. A 38-year-old Caucasian male patient complained of pain on lateral aspect of the leg when playing football. Pain progressively worsened until he had to stop the sporting activity. Radiographs, and then CT and MRI, showed OIM in the middle third of the left leg. MRI showed inflammation of tibia periosteum and bone adjacent to the ossification, which was then excised. Two months after surgery the patient returned to play football. Conclusion. A thorough analysis of the literature revealed three types of OIM of the leg in athletes. Type I usually occurs after a syndesmosis ankle sprain, Type II appears to result from a tibia fracture, and Type III, of which only one fully recorded case has been published, is probably caused, as in our patient, by repetitive minor traumas to the leg. Awareness of the existence of Type III OIM can avoid erroneous diagnoses leading to useless investigations and treatments.

#8 A wrong move in an amateur football player reveals a light chain myeloma
Reference: Ann Biol Clin (Paris). 2016 Feb 1;74(1):103-105.
Authors: Peyneau M, Nassiri S, Myara A, Ohana S, Laplanche S
Summary: Light chain multiple myeloma is a hematologic malignancy characterized by an excess of tumor plasma cells in the bone marrow and a monoclonal light chain in blood. It is generally diagnosed in patients aged 60-75 years old. Hypercalcemia, anemia, kidney failure, and bone pains are the main clinical and biological signs. Here is an atypical case report about a 30 year-old man who was diagnosed a light chain multiple myeloma. This patient had been suffering from back pain for 5 months. Osteolytic lesions were discovered on X-rays prescribed by the family practitioner. Admitted to the Emergency department, all blood tests showed results within the normal range. The serum protein electrophoresis was also normal. Only the urine analysis showed proteinuria. The urine immunofixation electrophoresis showed a massive κ light chain. The bone marrow aspiration cell count confirmed the myeloma diagnosis with an infiltration of dystrophic plasma cells. The patient was transferred to the hematology ward of Necker Hospital for treatment of light chain myeloma.

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