[beta]-Hydroxy-F128b-Methylbutyrate (HMB) Supplementation and the Promotion of Muscle Growth and Strength

[beta]-Hydroxy [beta]-methylbutyrate (HMB), a metabolite of the essential amino acid leucine, is one of the latest dietary supplements promoted to enhance gains in strength and lean body mass associated with resistance training. Unlike anabolic hormones that induce muscle hypertrophy by increasing muscle protein synthesis, HMB is claimed to influence strength and lean body mass by acting as an anticatabolic agent, minimising protein breakdown and damage to cells that may occur with intense exercise. Research on HMB has recently tested this hypothesis, under the assumption that it may be the active compound associated with the anticatabolic effects of leucine and its metabolites. While much of the available literature is preliminary in nature and not without methodological concern, there is support for the claims made regarding HMB supplementation, at least in young, previously untrained individuals. A mechanism by which this may occur is unknown, but research undertaken to date suggests there may be a reduction in skeletal muscle damage, although this has not been assessed directly. The response of resistance trained and older individuals to HMB administration is less clear. While the results of research conducted to date appear encouraging, caution must be taken when interpreting outcomes as most manuscripts are presented in abstract form only, not having to withstand the rigors of peer review. Of the literature reviewed relating to HMB administration during resistance training, only 2 papers are full manuscripts appearing in peer reviewed journals. The remaining 8 papers are published as abstracts only, making it difficult to critically review the research. There is clearly a need for more tightly controlled, longer duration studies to verify if HMB enhances strength and muscular hypertrophy development associated with resistance training across a range of groups, including resistance trained individuals.

The Scientific Basis for High-Intensity Interval Training: Optimising Training Programmes and Maximising Performance in Highly Trained Endurance Athletes

While the physiological adaptations that occur following endurance training in previously sedentary and recreationally active individuals are relatively well understood, the adaptations to training in already highly trained endurance athletes remain unclear. While significant improvements in endurance performance and corresponding physiological markers are evident following submaximal endurance training in sedentary and recreationally active groups, an additional increase in submaximal training (i.e. volume) in highly trained individuals does not appear to further enhance either endurance performance or associated physiological variables [e.g. peak oxygen uptake (V-dot O2peak), oxidative enzyme activity]. It seems that, for athletes who are already trained, improvements in endurance performance can be achieved only through high-intensity interval training (HIT). The limited research which has examined changes in muscle enzyme activity in highly trained athletes, following HIT, has revealed no change in oxidative or glycolytic enzyme activity, despite significant improvements in endurance performance (p < 0.05). Instead, an increase in skeletal muscle buffering capacity may be one mechanism responsible for an improvement in endurance performance. Changes in plasma volume, stroke volume, as well as muscle cation pumps, myoglobin, capillary density and fibre type characteristics have yet to be investigated in response to HIT with the highly trained athlete. Information relating to HIT programme optimisation in endurance athletes is also very sparse. Preliminary work using the velocity at which V-dot O2max is achieved (Vmax) as the interval intensity, and fractions (50 to 75%) of the time to exhaustion at Vmax (Tmax) as the interval duration has been successful in eliciting improvements in performance in long-distance runners. However, Vmax and Tmax have not been used with cyclists. Instead, HIT programme optimisation research in cyclists has revealed that repeated supramaximal sprinting may be equally effective as more traditional HIT programmes for eliciting improvements in endurance performance. Further examination of the biochemical and physiological adaptations which accompany different HIT programmes, as well as investigation into the optimal HIT programme for eliciting performance enhancements in highly trained athletes is required.

Presentation and mechanisms of concussion in professional Rugby League football

The present study prospectively recorded the circumstances, incidence, mechanisms, injury detection and presentation of concussion in Rugby League. Forty-three consecutive concussions were recorded over three competitive seasons in 175 professional Rugby League players. Data showed (i) the incidence of concussion ranged from 5.9 to 9.8 injuries/1000 player hours across grades - except when age-group players were mismatched (18.4); (ii) 'head-high tackles' accounted for a significant number of concussions; (iii) concussion rarely involved a loss of consciousness with the most common indicators of concussion being amnesia, headache and unsteadiness, with the mechanism of injury often missed; and (iv) concussion often occurs concurrently with other injuries. Concussion (including repeated episodes) is a common injury in Rugby League. Systematic mental status questioning is warranted whenever concussion is suspected. Coaches, trainers and players need more education in the recognition and management of concussion. Stricter penalties for illegal 'head-high' tackling are strongly recommended.

Cost effectiveness of adding magnetic resonance imaging to the usual management of suspected scaphoid fractures

Objective: To determine the cost effectiveness of a magnetic resonance imaging scan (MRI) within 5 days of injury compared with the usual management of occult scaphoid fracture. Methods: All patients with suspected scaphoid fractures in five hospitals were invited to participate in a randomised controlled trial of usual treatment with or without an MRI scan. Healthcare costs were compared, and a cost effectiveness analysis of the use of MRI in this scenario was performed. Results: Twenty eight of the 37 patients identified were randomised: 17 in the control group, 11 in the MRI group. The groups were similar at baseline and follow up in terms of number of scaphoid fractures, other injuries, pain, and function. Of the patients without fracture, the MRI group had significantly fewer days immobilised: a median of 3.0 (interquartile range 3.0-3.0) v 10.0 (7-12) in the control group (p = 0.006). The MRI group used fewer healthcare units (median 3.0, interquartile range 2.0-4.25) than the control group (5.0, 3.0-6.5) (p = 0.03 for the difference). However, the median cost of health care in the MRI group ($594.35 AUD, $551.35-667.23) was slightly higher than in the control group ($428.15, $124.40-702.65) (p = 0.19 for the difference). The mean incremental cost effectiveness ratio derived from this simulation was that MRI costs $44.37 per day saved from unnecessary immobilisation (95% confidence interval $4.29 to $101.02). An illustrative willingness to pay was calculated using a combination of the trials measure of the subjects' individual productivity losses and the average daily earnings. Conclusions: Use of MRI in the management of occult scaphoid fracture reduces the number of days of unnecessary immobilisation and use of healthcare units. Healthcare costs increased non-significantly in relation to the use of MRI in this setting. However, when productivity losses are considered, MRI may be considered cost effective, depending on the individual case.

Creatine Activates Airway Epithelium in Asthma

Airway epithelium plays important roles in the pathophysiology of asthma. Creatine supplementation (Cr) was shown to increase asthma features in a murine model of allergic asthma; however, the role of the airway epithelium in this inflammatory response is not known. BALB/c mice were divided into control, creatine supplementation, ovalbumin-sensitized (OVA) and OVA plus creatine supplementation groups. OVA sensitization occurred on days 0, 14, 28 and 42, and ovalbumin challenge from days 21-53. Cr was also given on days 21-53. Total and differential cells counts in BALF were evaluated. Quantitative epithelial expression of interleukin (IL)-4, IL-5, IL-13, CCL11, CCL5, CCL2, iNOS, VCAM-1, ICAM-1, NF-kappa B, VEGF, TGF-beta, IGF-1, EGFR, TIMP-1, TIMP-2, MMP-9, MMP-12 and arginase II were performed. Cr increased the number of total cells and eosinophils in BALF, the epithelial content of goblet cells and the epithelial expression of IL-5, CCL2, iNOS, ICAM-1, NF-kappa B, TGF-beta, TIMP-1 and MMP-9 when compared to the control group (p < 0.05). Creatine supplementation also exacerbated goblet cell proliferation, and IL-5 and iNOS expression by epithelial cells compared to the OVA group (p < 0.01). Creatine up-regulates the pro-inflammatory cascade and remodelling process in this asthma model by modulating the expression of inflammatory mediators by epithelial cells.

In-shoe plantar pressure distribution during running on natural grass and asphalt in recreational runners

The type of surface used for running can influence the load that the locomotor apparatus will absorb and the load distribution could be related to the incidence of chronic injuries. As there is no consensus on how the locomotor apparatus adapts to loads originating from running Surfaces with different compliance, the objective of this study was to investigate how loads are distributed over the plantar surface while running on natural grass and on a rigid surface-asphalt. Forty-four adult runners with 4 3 years of running experience were evaluated while running at 12 km/h for 40 m wearing standardised running shoes and Pedar insoles (Novel). Peak pressure, contact time and contact area were measured in six regions: lateral, central and medial rearfoot, midfoot, lateral and media] forefoot. The Surfaces and regions were compared by three ANOVAS (2 x 6). Asphalt and natural grass were statistically different in all variables. Higher peak pressures were observed on asphalt at the central (p < 0.001) [grass: 303.8(66.7) kPa; asphalt: 342.3(76.3) kPa] and lateral rearfoot (p < 0.001) [grass: 312.7(75.8) kPa: asphalt: 350.9(98.3) kPa] and lateral forefoot (p < 0.001) [grass: 221.5(42.9) kPa asphalt: 245.3(55.5) kPa]. For natural grass, contact time and contact area were significantly greater at the central rearfoot (p < 0.001). These results suggest that natural grass may be a Surface that provokes lighter loads on the rearfoot and forefoot in recreational runners. (C) 2008 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Exercise Reduces Effects of Creatine on Lung

We recently demonstrated that creatine supplementation increased some features of lung allergic sensitization in mice. On the other hand, other studies have shown that aerobic exercise inhibited allergic airway inflammation and remodeling. We hypothesized that aerobic exercise may decrease the exacerbatory effects of the creatine supplementation in a murine model of asthma. Balb/c mice were divided into six groups: Control, Creatine (Cr), Low Intensity Exercise + Creatine (Low + Cr), Ovalbumin (OVA), Ovalbumin + Creatine (OVA + Cr) and Ovalbumin + Creatine + Low Intensity Exercise (OVA + Cr + Low). OVA-sensitized groups were sensitized with OVA intraperitoneal injections (days 0, 14, 28, and 42). Aerosol challenge (OVA 1 %) and Cr treatment (0.5 g/kg/day) were initiated on Day 21 until Day 53. Low intensity exercise began on day 22 and was sustained until day 50. Low intensity exercise in the presence of creatine supplementation in sensitized mice resulted in a decreased number of eosinophils in BALF (p < 0.001) and in the airways (P < 0.001), and a decreased density of inflammatory cells positive to IL-4 (p < 0.001) and IL-5 (p < 0.001), airway collagen (p < 0.001) and elastic fibers (p < 0.001) content, airway smooth muscle thickness (p < 0.001) and bronchoconstriction index (p < 0.05) when compared with OVA + Cr group. These results suggest that aerobic exercise reduces the exacerbatory effects of creatine supplementation in chronically sensitized mice.

Physical Training Leads to Remodeling of Diaphragm Muscle in Asthma Model

Matrix metalloproteinases (MMPs) are crucial to the development and maintenance of healthy tissue and are mainly involved in extracellular matrix (ECM) remodeling of skeletal muscle. This study evaluated the effects of chronic allergic airway inflammation (CAAI), induced by ovalbumin, and aerobic training in the MMPs activity in mouse diaphragm muscle. Thirty mice were divided into 6 groups: 1) control; 2) ovalbumin; 3) treadmill trained at 50% of maximum speed; 4) ovalbumin and trained at 50%; 5) trained at 75%; 6) ovalbumin and trained at 75%. CAAI did not after MMPs activities in diaphragm muscle. Nevertheless, both treadmill aerobic trainings, associated with CAAI increased the MMP-2 and -1 activities. Furthermore, MMP-9 was not detected in any group. Together, these findings suggest an ECM remodeling in diaphragm muscle of asthmatic mice submitted to physical training. This result may be useful for a better understanding of functional significance of changes in the MMPs activity in response to physical training in asthma.

Resistance Exercise Intensity Progression in Older Men

Our purpose was to examine possible influences of age on resistance exercise (RE) intensity progression in men. Twenty-four men, divided in young sedentary (YS; n = 10; 25.9 +/- 3.7 years), older sedentary (OS; n = 7; 67.4 +/- 5.2 years), and older runners (OR; n = 7; 71.3 +/- 3.0 years), underwent a 2 times-a-week RE program for 13 weeks. Muscle strength was assessed before and after training by 1-repetition maximum test. RE workloads were recorded for each exercise session, and increases of 5-10% were made whenever adaptation occurred. Muscle strength improved similarly in all groups after RE (P < 0.001). Relative RE intensity progression was not significantly different between YS and OS, except for a greater increase in calf raise relative workload observed in YS (P < 0.05). In contrast, OR displayed greater relative workload increase in 7 and 6 exercises than YS and OS, respectively (P < 0.05). The RE was safe as no injuries or major muscle pain were observed in either group. These results suggest that healthy sedentary older men are capable to exercise and increase RE intensity in the same way as young men, while physically active older men are capable to increase RE intensity in greater way than sedentary young and older men.

Translation and Cross-Cultural Adaptation of the Brazilian Version of the International Knee Documentation Committee Subjective Knee Form Validity and Reproducibility

Background: The perception of improvement by a patient has assumed a central role in functional evaluation after a variety of knee problems. One of the instruments most used in clinical research is the International Knee Documentation Committee (IKDC) Subjective Knee Form because its psychometric properties are considered to be excellent. Nonetheless, this questionnaire was originally developed for use in the English language. Therefore, to use this questionnaire in the Brazilian population, it is essential to translate and validate it. Purpose: The aim of this study was to translate the IKDC Subjective Knee Form into a Brazilian version and to test its validity and reproducibility. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: The translation of the original IKDC Subjective Knee Form into a Brazilian version was accomplished in accordance with the American Orthopaedic Society for Sports Medicine guidelines and was tested in 32 patients with knee pathologic conditions to develop the first Brazilian version. To test validity and reproducibility, 117 patients with several knee complaints completed the Brazilian IKDC Subjective Knee Form, the Short Form 36 (SF-36), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Lysholm score. From these patients, 85 were retested within a week to achieve reproducibility. The validation was addressed by correlating the Brazilian IKDC Subjective Knee Form to the other outcome measures. The reproducibility was tested by measuring internal consistency, test-retest reliability, and agreement. Results: The Brazilian IKDC Subjective Knee Form was highly related to the physical component summary of the SF-36, the Lysholm score, and the WOMAC, and weakly related to the mental component summary of SF-36 (r=.79, .89, .85, and .51, respectively). The internal consistency was strong, with a Cronbach a value of .928 and .935 in the test and retest assessment, respectively. The test-retest reliability proved to be excellent, with a high value of the intraclass correlation coefficient (.988), as well as the agreement, demonstrated by the low differences between the means of the test and retest, and the short limit of agreement, observed in the Altman-Bland and survival-agreement plots. Conclusion: The results of this study provide evidence that the Brazilian IKDC Subjective Knee Form has psychometric properties similar to the original version. In addition, it was a reliable evaluation instrument for patients with knee-related problems.

Blood and Salivary Oxidative Stress Biomarkers Following an Acute Session of Resistance Exercise in Humans

The aim of the present study was to compare oxidative stress biomarkers determined in blood and saliva before and after acute resistance exercise. 1 week after 1 maximum repetition (1RM) test 11 healthy well-trained males completed a hypertrophy acute session of resistance training including 3 sets of 10 repetitions at 75% of the 1RM, with 90s rest periods between sets. Venous blood and saliva samples were collected before (pre) and 10 min after (post) the resistance training session. A significant (p < 0.05) rise in blood lactate accumulation (pre: 1.6 +/- 0.4 vs. post: 9.5 +/- 2.4) was found post-acute resistance training compared with baseline values. Significant increases (p < 0.05) in TBARS (42%), AOPP (28%), uric acid (27%) and GSH (14%) were detected post-acute resistance training in relation to pre in blood samples. A significant increase (p < 0.05) in uric acid (36%) was found in saliva post-acute resistance training as well as a significant correlation (p < 0.05) between uric acid determined in blood and saliva. Statistical analysis did not reveal any other change in the salivary oxidative stress biomarkers. In conclusion, an acute session of resistance exercise induces oxidative stress in plasma of trained men after acute resistance training, which was not found in saliva samples except for uric acid.

Effects of Ipratropium on Exercise-Induced Bronchospasm

Exercise-induced bronchospasm (EIB) is the transient narrowing of the airways that follows vigorous exercise. Ipratropium bromide may be used to prevent EIB, but its effect varies among individuals. We hypothesized that time of administration of ipratropium interferes with its action. This was a prospective, double-blind, cross-over study carried out to evaluate the bronchoprotective and bronchodilatory effect of ipratropium at different times of day. The study consisted of 4 exercise challenge tests (2 at 7 am and 2 at 6 pm). In the morning, one of the tests was performed after placebo administration and the other one after ipratropium (80 mu g) and the two tests (placebo and ipratropium) were repeated in the evening. Twenty-one patients with severe or moderate asthma and previous confirmation of EIB were enrolled in this prospective trial. The bronchodilatory effect of ipratropium was 0.25 +/- 0.21 L or 13.11 +/- 10.99 % (p = 0.001 compared to baseline values) in the morning, and 0.14 +/- 0.25 L or 7.25 +/- 11.37 % (p > 0.05) in the evening. In the morning, EIB was 0.58 +/- 0.29 L on the placebo day and 0.38 +/- 0.22 L on the treatment day (p = 0.01). In the evening, EIB was 0.62 +/- 0.28 L on the placebo day and 0.51 +/- 0.35 L on the treatment day (p > 0.05). We suggest that the use of ipratropium for the treatment of asthma and EIB should take into consideration the time of administration.

Fluid shifts resulting from exercise in rats as detected by bioelectrical impedance

Purpose: This study was designed to investigate the immediate effect of exercise intensity and duration on body fluid volumes in rats throughout a 3-wk exercise program. Methods: Changes in the extracellular water (ECW) and total body water (TBW) volumes of rats were measured preexercise and postexercise using multiple frequency bioelectrical impedance analysis. Groups of rats were exercised at two intensities (6 m.min(-1) and 12 m.min(-1)) for two exercise times (60 min and 90 min) 5 d.wk(-1) during a 3-wk period. Changes in plasma electrolytes, glucose, and lactate resulting from the exercise were also measured on 3 d of each week. Results: Each group of animals showed significant losses in ECW and TBW as a direct result of daily exercise. The magnitude of fluid loss was directly related to the intensity of the exercise, bur not to exercise duration; although the magnitude of daily fluid loss at the higher intensity exercise (12 m.min(-1)) decreased as the study progressed, possibly indicating a training effect. Conclusion: At low-intensity exercise, there is a small bur significant loss in both TBW and ECW fluids, and the magnitude of these losses does not change throughout a 3-wk exercise program. At moderate levels of exercise intensity, there is a greater loss of both TBW and ECW fluids. However, the magnitudes of these losses decrease significantly during the 3-wk exercise program, thus demonstrating a training effect.