leakage of myofiber proteins ( Clarkson & Hubal, 2002 ). These metabolic events are associated with delayed onset of muscle soreness (DOMS) and local muscular inflammation 24–48 hours after exercise ( Armstrong, 1984 ; Fridén & Lieber, 2001 ). With a view to minimizing muscle damage and/or accelerating
Jordan D. Philpott, Chris Donnelly, Ian H. Walshe, Elizabeth E. MacKinley, James Dick, Stuart D.R. Galloway, Kevin D. Tipton and Oliver C. Witard
Hellen C.G. Nabuco, Crisieli M. Tomeleri, Rodrigo R. Fernandes, Paulo Sugihara Junior, Edilaine F. Cavalcante, Danielle Venturini, Décio S. Barbosa, Analiza M. Silva, Luís B. Sardinha and Edilson S. Cyrino
al., 2016 ; Tomeleri et al., 2016 , 2018 ). A growing body of evidence indicates that higher protein intake may improve MetS risk factors ( Mirmiran, Hajifaraji, Bahadoran, Sarvghadi, & Aziz, 2012 ; Nabuco et al., 2018a ; Pal & Radavelli-Bagatini, 2013 ), and when combined with RT could promote an
Rebekah D. Alcock, Gregory C. Shaw, Nicolin Tee, Marijke Welvaert and Louise M. Burke
Musculoskeletal injuries are a common occurrence within athletic populations and may place a significant burden on the professional athlete and/or his or her respective team ( Kreisfeld et al., 2014 ). Collagen, which makes up approximately one third of total body protein ( Shoulders et al., 2009
Liam Anderson, Robert J. Naughton, Graeme L. Close, Rocco Di Michele, Ryland Morgans, Barry Drust and James P. Morton
The daily distribution of macronutrient intake can modulate aspects of training adaptations, performance and recovery. We therefore assessed the daily distribution of macronutrient intake (as assessed using food diaries supported by the remote food photographic method and 24-hr recalls) of professional soccer players (n = 6) of the English Premier League during a 7-day period consisting of two match days and five training days. On match days, average carbohydrate (CHO) content of the prematch (<1.5 g·kg-1 body mass) and postmatch (1 g·kg-1 body mass) meals (in recovery from an evening kick-off) were similar (p > .05) though such intakes were lower than contemporary guidelines considered optimal for prematch CHO intake and postmatch recovery. On training days, we observed a skewed and hierarchical approach (p < .05 for all comparisons) to protein feeding such that dinner (0.8 g·kg-1)>lunch (0.6 g·kg-1)>breakfast (0.3 g·kg-1)>evening snacks (0.1 g·kg-1). We conclude players may benefit from consuming greater amounts of CHO in both the prematch and postmatch meals so as to increase CHO availability and maximize rates of muscle glycogen resynthesis, respectively. Furthermore, attention should also be given to ensuring even daily distribution of protein intake so as to potentially promote components of training adaptation.
Susan J. Massad, Nathan W. Shier, David M. Koceja and Nancy T. Ellis
Factors influencing nutritional supplement use by high school students were assessed. Comparisons were made between various groups of sports participants and non-sports participants. The Nutritional Supplement Use and Knowledge Scale was administered to 509 students. Mean supplement use score was 10.87 (SEM = 0.50, range 0-57). Mean knowledge score was 13.56 (SEM = 0.16, range 1-21). Significant relationships (p < .01) were obtained for supplement knowledge with use, and supplement use with gender. ANOVA found significant differences between supplement use by gender (p < .01), supplement use by sports category (p < .05), and knowledge scores by sports category (p < .01). Discriminant function analysis indicated knowledge, supplement use, and subscores for protein, vitamins/minerals, and carbohydrates were best discriminators of sport group membership. Greater knowledge about supplements was associated with less use; hence, education about supplements can be a deterrent to use. This study may help coaches, athletic trainers, athletic directors, teachers, physicians, and parents identify nutritional misconceptions held by adolescents.
Jordan Milsom, Paulo Barreira, Darren J. Burgess, Zafar Iqbal and James P. Morton
The onset of injury and subsequent period of immobilization and disuse present major challenges to maintenance of skeletal muscle mass and function. Although the characteristics of immobilization-induced muscle atrophy are well documented in laboratory studies, comparable data from elite athletes in free-living conditions are not readily available. We present a 6-month case-study account from a professional soccer player of the English Premier League characterizing rates of muscle atrophy and hypertrophy (as assessed by DXA) during immobilization and rehabilitation after ACL injury. During 8 weeks of inactivity and immobilization, where the athlete adhered to a low carbohydrate-high protein diet, total body mass decreased by 5 kg attributable to 5.8 kg loss and 0.8 kg gain in lean and fat mass, respectively. Changes in whole-body lean mass was attributable to comparable relative decreases in the trunk (12%, 3.8 kg) and immobilized limb (13%, 1.4 kg) whereas the nonimmobilized limb exhibited smaller declines (7%, 0.8 kg). In Weeks 8 to 24, the athlete adhered to a moderate carbohydrate-high protein diet combined with structured resistance and field based training for both the lower and upper-body that resulted in whole-body muscle hypertrophy (varying from 0.5 to 1 kg per week). Regional hypertrophy was particularly pronounced in the trunk and nonimmobilized limb during weeks 8 to 12 (2.6 kg) and 13 to 16 (1.3 kg), respectively, whereas the previously immobilized limb exhibited slower but progressive increases in lean mass from Week 12 to 24 (1.2 kg). The athlete presented after the totality of the injured period with an improved anthropometrical and physical profile.
Graeme L. Close, Craig Sale, Keith Baar and Stephane Bermon
repair. Given the crucial role of dietary protein in muscle protein turnover, it is not surprising that much attention has been given to dietary protein in the prevention of muscle injuries. It is accepted that the provision of dietary proteins enhances the adaptive processes to both resistance- and
Katherine Elizabeth Black, Alistair David Black and Dane Frances Baker
databases (Web of Science, PubMed, and SPORTDiscus) were searched using the search terms Rugby AND (Nutrition or Diet or Energy OR Macronutrients OR Carbohydrate OR Protein OR Fat). Any additional relevant literature was obtained from the reference lists of the published papers. The inclusion criteria were
Mike Pryzbek, Julie Richardson, Lehana Thabane and Ada Tang
-reactive protein (hs-CRP), which is elevated in the presence of cardiovascular disease ( Rost et al., 2001 ). While systemic biomarker levels cannot pinpoint the specific location of inflammation, elevated hs-CRP is a reliable predictor of cardiovascular events ( Rost et al., 2001 ) and is an established risk
Shane Bilsborough and Neil Mann
Considerable debate has taken place over the safety and validity of increased protein intakes for both weight control and muscle synthesis. The advice to consume diets high in protein by some health professionals, media and popular diet books is given despite a lack of scientific data on the safety of increasing protein consumption. The key issues are the rate at which the gastrointestinal tract can absorb amino acids from dietary proteins (1.3 to 10 g/h) and the liver’s capacity to deaminate proteins and produce urea for excretion of excess nitrogen. The accepted level of protein requirement of 0.8g · kg−1 · d−1 is based on structural requirements and ignores the use of protein for energy metabolism. High protein diets on the other hand advocate excessive levels of protein intake on the order of 200 to 400 g/d, which can equate to levels of approximately 5 g · kg−1 · d−1, which may exceed the liver’s capacity to convert excess nitrogen to urea. Dangers of excessive protein, defined as when protein constitutes > 35% of total energy intake, include hyperaminoacidemia, hyperammonemia, hyperinsulinemia nausea, diarrhea, and even death (the “rabbit starvation syndrome”). The three different measures of defining protein intake, which should be viewed together are: absolute intake (g/d), intake related to body weight (g · kg−1 · d−1) and intake as a fraction of total energy (percent energy). A suggested maximum protein intake based on bodily needs, weight control evidence, and avoiding protein toxicity would be approximately of 25% of energy requirements at approximately 2 to 2.5 g · kg−1 · d−1, corresponding to 176 g protein per day for an 80 kg individual on a 12,000kJ/d diet. This is well below the theoretical maximum safe intake range for an 80 kg person (285 to 365 g/d).