We determined the effects of intravenous infusion of amino acids (AA) at serum insulin of 5, 30, 72, and 167 mU/l on anabolic signaling, expression of ubiquitin-proteasome components, and protein turnover in muscles of healthy young men. Tripling AA availability at 5 mU/l insulin doubled incorporation of [1-13C]leucine [i.e., muscle protein synthesis (MPS), P < 0.01] without affecting the rate of leg protein breakdown (LPB; appearance of d5-phenylalanine). While keeping AA availability constant, increasing insulin to 30 mU/l halved LPB (P < 0.05) without further inhibition at higher doses, whereas rates of MPS were identical to that at 5 mU/l insulin. The phosphorylation of PKB Ser473 and p70S6k Thr389 increased concomitantly with insulin, but whereas raising insulin to 30 mU/l increased the phosphorylation of mTOR Ser2448, 4E-BP1 Thr37/46, or GSK3β Ser9 and decreased that of eEF2 Thr56, higher insulin doses to 72 and 167 mU/l did not augment these latter responses. MAFbx and proteasome C2 subunit proteins declined as insulin increased, with MuRF-1 expression largely unchanged. Thus increasing AA and insulin availability causes changes in anabolic signaling and amounts of enzymes of the ubiquitin-proteasome pathway, which cannot be easily reconciled with observed effects on MPS or LPB.

Skeletal muscle atrophy occurs as a consequence of injury, illness, surgery, and muscle disuse, impacting appreciably on health care costs and patient quality of life, particularly in the absence of appropriate rehabilitation. The molecular mechanisms that regulate muscle mass during atrophy and rehabilitation in humans have not been elucidated, despite several robust candidate pathways being identified. Here, we induced skeletal muscle atrophy in healthy volunteers using two weeks of limb immobilization, and then stimulated the restoration of muscle mass with six weeks of supervised exercise rehabilitation. We determined muscle mass and function and performed targeted gene expression analysis at prescribed time points during immobilization and rehabilitation. For the first time, we have identified novel changes in gene expression following immobilization-induced atrophy and during a program of rehabilitative exercise that restored muscle mass and function. Furthermore, we have shown that exercise performed immediately following immobilization induces profound changes in the expression of a number of genes in favor of the restoration of muscle mass, within 24 h. This information will be of considerable importance to our understanding of how immobilization and contraction stimulate muscle atrophy and hypertrophy, respectively, and to the development of novel therapeutic strategies aimed at maintaining or restoring muscle mass.

Cricket was the first sport to publish recommended methods for injury surveillance in 2005. Since then, there have been changes to the nature of both cricket and injury surveillance. Researchers representing the major cricket playing nations met to propose changes to the previous recommendations, with an agreed voting block of 14. It was decided that 10 of 14 votes (70%) were required to add a new definition element and 11 of 14 (80%) were required to amend a previous definition. In addition to the previously agreed ‘Match time-loss’ injury, definitions of ‘General time-loss’, ‘Medical presentation’, ‘Player-reported’ and ‘Imaging-abnormality’ injuries are now provided. Further, new injury incidence units of match injuries per 1000 player days, and annual injuries per 100 players per year are recommended. There was a shift towards recommending a greater number of possible definitions, due to differing contexts and foci of cricket research (eg, professional vs amateur; injury surveillance systems vs specific injury category studies). It is recommended that researchers use and report as many of the definitions as possible to assist both comparisons between studies within cricket and with those from other sports.

The COVID-19 pandemic in 2020 has resulted in widespread training disruption in many sports. Some athletes have access to facilities and equipment, while others have limited or no access, severely limiting their training practices. A primary concern is that the maintenance of key physical qualities (e. g. strength, power, high-speed running ability, acceleration, deceleration and change of direction), game-specific contact skills (e. g. tackling) and decision-making ability, are challenged, impacting performance and injury risk on resumption of training and competition. In extended periods of reduced training, without targeted intervention, changes in body composition and function can be profound. However, there are strategies that can dramatically mitigate potential losses, including resistance training to failure with lighter loads, plyometric training, exposure to high-speed running to ensure appropriate hamstring conditioning, and nutritional intervention. Athletes may require psychological support given the challenges associated with isolation and a change in regular training routine. While training restrictions may result in a decrease in some physical and psychological qualities, athletes can return in a positive state following an enforced period of rest and recovery. On return to training, the focus should be on progression of all aspects of training, taking into account the status of individual athletes.

Exercise is frequently recommended in the management of type 1 and 2 diabetes mellitus and can improve glucose uptake by increasing insulin sensitivity and lowering body adiposity. Both alone and when combined with diet and drug therapy, physical activity can result in improvements in glycaemic control in type 2 diabetes. In addition, exercise can also help to prevent the onset of type 2 diabetes, in particular in those at higher risk, and has an important role in reducing the significant worldwide burden of this type of diabetes. Recent studies have improved our understanding of the acute and long term physiological benefits of physical activity, although the precise duration, intensity, and type of exercise have yet to be fully elucidated. However, in type 1 diabetes, the expected improvements in glycaemic control with exercise have not been clearly established. Instead significant physical and psychological benefits of exercise can be achieved while careful education, screening, and planning allow the metabolic, microvascular, and macrovascular risks to be predicted and diminished. (Br J Sports Med 1999;33:161-173)

BackgroundSport participants are at increased risk of joint pain and osteoarthritis. A better understanding of factors associated with joint pain and osteoarthritis in this population could inform the development of strategies to optimise their long-term joint health. The purpose of the study was to describe the prevalence of joint pain and osteoarthritis in former cricketers, and determine whether playing position, playing standard (i.e. elite or recreational standard) and length-of-play are associated with region-specific joint pain.MethodsThe data were from the Cricket Health and Wellbeing Study (CHWS), a cohort of 2294 current and former cricketers (played ≥1 season) in England and Wales. For this study, eligible individuals had to be aged ≥30 years and be a former cricket participant. Joint pain was defined as region-specific (hip/knee/ankle/shoulder/hand/back) pain on most days of the last month. Osteoarthritis was defined as joint-specific doctor-diagnosed osteoarthritis. Logistic regression was used to calculate unadjusted and adjusted (for history of joint injury resulting in > 4 weeks of reduced activity +/− age) odds ratios (ORs) and 95% confidence intervals (95% CIs).Results846 individuals from the CHWS were former cricketers aged ≥30 years (3% female, aged median 62(IQR 54–69) years, 62% played cricket recreationally, median 33(IQR 21–41) cricket seasons). One-in-two (48%) reported joint pain and 38% had been diagnosed with osteoarthritis. Joint pain and OA were most common in the knee (23% pain, 22% osteoarthritis), followed by the back (14% pain, 10% osteoarthritis) and hand (12% pain, 6% osteoarthritis). After adjusting for injury, bowlers had greater odds of shoulder pain (OR (95% CI) 3.1(1.3, 7.4)) and back pain (3.6(1.8, 7.4)), and all-rounders had greater odds of knee (1.7(1.0, 2.7)) and back pain (2.1(1.0, 4.2)), compared to batters. Former elite cricketers had greater odds of hand pain (1.6(1.0, 2.5)) than former recreational cricketers. Playing standard was not related to pain at other sites, and length-of-play was not associated with joint pain in former cricketers.ConclusionsEvery second former cricketer experienced joint pain on most days of the last month, and more than one in three had been diagnosed with osteoarthritis. Compared with batters, bowlers had higher odds of shoulder and back pain and all-rounders had higher odds of back and knee pain. Elite cricket participation was only related to higher odds of hand pain compared with recreational cricket participation.

Introduction: Lumbar bone stress injuries (LBSI) are the most prevalent injury in cricket.While fast bowling technique has been implicated in the aetiology of LBSI, no previous study has attempted to prospectively analyse fast bowling technique and its relationship to LBSI.The aim of this study was to explore technique differences between elite cricket fast bowlers with and without subsequent LBSI. Methods: Kinematic and kinetic technique parameters previously associated with LBSI were determined for 50 elite male fast bowlers.Group means were compared using independent samples t-tests to identify differences between bowlers with and without a prospective LBSI. Significant parameters were advanced as candidate variables for a binary logistic regression analysis. Results: Of the 50 bowlers, 39 sustained a prospective LBSI. Significant differences were found between injured and non-injured bowlers in: rear knee angle, rear hip angle, thoracolumbar side flexion angle and thoracolumbar rotation angle at back foot contact (BFC); the front hip angle, pelvic tilt orientation and lumbopelvic angle at front foot contact (FFC); the thoracolumbar side flexion angle at ball release and the maximum front hip angle and ipsilateral pelvic drop orientation. A binary logistic model, consisting of rear hip angle at BFC 2 and lumbopelvic angle at FFC, correctly predicted 88% of fast bowlers according to injury history and significantly increased the odds of sustaining an LBSI (odds ratio: 0.88 and 1.25 respectively). Conclusion: Lumbopelvic motion is implicated in the aetiology of LBSI in fast bowling with inadequate lumbo-pelvi-femoral complex control a potential cause. This research will aid the identification of fast bowlers at risk of LBSI, as well as enhancing coaching and rehabilitation of fast bowlers from LBSI.

AbstractThis prospective cohort study aimed to describe injury and illness epidemiology within women’s international pathway cricket, understanding what influences player availability in this unique context where players are contracted part-time. Approximately 8.4% of players were impacted by injury or illness during the year, with an average 2.3% of players completely unavailable on any given day. Most medical complaints occurred during training (111.2 injuries/100 players per year). Of all complaints, medical illness had the highest overall incidence (45.0 complaints/100 players), followed by hand injuries (24.7 injuries/100 players). Gradual onset injuries were most common. Overall average match time-loss complaint prevalence rate was 4.1% and average match time-loss injury incidence rate was 7.0 injuries/1000 days of play. Fielding (56.4 injuries/100 players per year) was the activity resulting in the highest average overall and time-loss injury incidence rates, though ‘other’ activities (e. g. those occurring outside of cricket participation) collectively accounted for 78.3 injuries/100 players per year. The high incidence of medical illness relative to other complaints may be a distinct feature of the women’s cricket international pathway compared to other cricket samples. The high occurrence of injuries arising from ‘other’ activities, likely due to part-time participation, presents an opportunity for targeted injury prevention strategies. Practical Implications