A similar injury profile observed in franchise men's and women's cricket in England and Wales: injury surveillance analysis from the first three 'The Hundred' competitions

Objectives

To describe the injury profile of a novel format cricket competition ('The Hundred') and compare injury incidence and prevalence between the men's and women's competitions.

Methods

Medical staff prospectively collected injury data from the eight men's and women's teams during the 2021-2023 competitions. Injury definitions and incidence calculations followed the international consensus statement.

Results

In the men's competition, 164 injuries were recorded, compared with 127 in the women's competition. Tournament injury incidence was 36.6 (95% CI 31.4 to 42.7) and 32.5 (95% CI 27.3 to 38.7)/100 players/tournament in the men's and women's competition, respectively. Non-time-loss incidence (men's 26.6 (95% CI 22.2 to 31.8), women's 24.6 (95% CI 20.1 to 30.0)/100 players/tournament) was higher than time-loss incidence (men's 10.0 (95% CI 7.5 to 13.5), women's 7.9 (95% CI 5.6 to 11.3)/100 players/tournament). Injury prevalence was 2.9% and 3.6% in the men's and women's competitions, respectively. Match fielding was the most common activity at injury in both competitions. The thigh and hand were the most common body location time-loss injury in the men's and women's competitions, respectively.

Conclusion

A similar injury profile was observed between the men's and women's competition. Preventative strategies targeting thigh injuries in the men's competition and hand injuries in the women's competition would be beneficial. Compared with published injury rates, 'The Hundred' men's presents a greater risk of injury than Twenty20 (T20), but similar to one-day cricket, with 'The Hundred' women's presenting a similar injury risk to T20 and one-day cricket. Additional years of data are required to confirm these findings.

English and Welsh men's domestic cricket injury risk by activity and cricket type: A retrospective cohort study from 2010 to 2019

OBJECTIVES

Explore whether injury profiles and mechanisms differ between red (First-Class multi-day) ball cricket and white (One-Day and Twenty20 limited over) ball cricket in elite men's domestic cricket from 2010 to 2019.

DESIGN

Retrospective cohort analysis.

METHODS

Injury incidence calculated according to the updated international consensus statement on injury surveillance in cricket, along with seasonal days lost and injury severity descriptive statistics.

RESULTS

Across both cricket types, bowling resulted in the most seasonal days lost (mean 1942, 95 % confidence interval: 1799-2096) and highest mean injury severity (30 days, 95 % confidence interval: 28-33), with the lumbar spine the body region with the most seasonal days lost (mean 432 seasonal days; 95 % confidence interval: 355-525) from bowling. Injury incidence was higher in white ball compared to red ball cricket (per unit of time), with bowling (and its various phases) the most frequently occurring mechanism in both cricket types (white ball: 67.0 injuries per 1000 days of play [95 % confidence interval: 59.6-75.3]; red ball: 32.4 injuries per 1000 days of play [95 % confidence interval: 29.1-36.1]). When bowling, the abdomen and thigh were the body regions most injured from white (13.4 injuries per 1000 days of play [95 % confidence interval: 10.3-17.4]), and red ball (6.4 injuries per 1000 days of play [95 % confidence interval: 5.0-8.2]) cricket respectively. Overall, clear differences emerged in the nature and mechanism of injuries between red ball cricket and white ball cricket.

CONCLUSIONS

Bowling presents the highest injury risk (across both cricket types), as well as highlighting the increased risk of injuries from diving during fielding and running between the wickets when batting, in shorter white ball cricket.

The impact of living in a bio-secure bubble on mental health: An examination in elite cricket

The COVID-19 pandemic has had a profound impact on many people's lives, including the use of bio-secure environments to facilitate the continuation of professional sport. Although it is well documented that the pandemic has negatively impacted mental health, the impact of bio-bubbles on mental health is yet to be investigated. In the present study we sought to identify the impact of bio-bubbles on the mental health of those residing within, and then to explore the underlying mechanism of any such impact. Individuals (n = 68) who resided in England and Wales Cricket Board (ECB) created bio-bubbles between March 2020 and April 2021 provided data, regarding their time inside and outside of bio-bubbles, on measures of mental health and basic psychological need satisfaction and frustration. Analysis revealed that bio-bubbles increased anxiety and depression and reduced wellbeing. Additionally, MEMORE mediation analyses revealed that autonomy frustration mediated the relationship between bubble status and all mental health markers. Furthermore, compared to men, women were more likely to experience elevated levels of anxiety and depression inside the bubble. The findings suggest that bio-bubbles negatively impact mental health and further suggest that satisfaction and frustration of basic psychological needs is a contributing factor. Findings suggest organizations tasked with creating bio-bubbles would do well to tailor their environment with an awareness of the importance of basic psychological needs and sex differences in relation to mental health. To the best of our knowledge, this research represents the first investigation of the impact of bio-bubbles on mental health.

Lumbar spine bone mineral adaptation: cricket fast bowlers versus controls

Elite adult male fast bowlers have high lumbar spine bone mineral, particularly on the contralateral side to their bowling arm. It is thought that bone possesses its greatest ability to adapt to loading during adolescence, but it is unknown at what age the greatest changes in lumbar bone mineral and asymmetry develops in fast bowlers.

Objectives

This study aims to evaluate the adaptation of the lumbar vertebrae in fast bowlers compared to controls and how this is associated with age.

Methods

91 male fast bowlers and 84 male controls aged 14-24 years had between one and three annual anterior-posterior lumbar spine dual-energy-X-ray absorptiometry scans. Total (L1-L4) and regional ipsilateral and contralateral L3 and L4 (respective to bowling arm) bone mineral density and content (BMD/C) were derived. Multilevel models examined the differences in lumbar bone mineral trajectories between fast bowlers and controls.

Results

At L1-L4 BMC and BMD, and contralateral BMD sites, fast bowlers demonstrated a greater negative quadratic pattern to their accrual trajectories than controls. Fast bowlers had greater increases in BMC in L1-L4 between 14 and 24 years of 55% compared with controls (41%). Within vertebra, asymmetry was evident in all fast bowlers and increased by up to 13% in favour of the contralateral side.

Conclusions

Lumbar vertebral adaptation to fast bowling substantially increased with age, particularly on the contralateral side. The greatest accrual was during late adolescence and early adulthood, which may correspond with the increasing physiological demands of adult professional sport.

Activity specific areal bone mineral density is reduced in athletes with stress fracture and requires profound recovery time: A study of lumbar stress fracture in elite cricket fast bowlers

OBJECTIVES

The aims of this study were to determine whether lumbar areal bone mineral density differed between cricket fast bowlers with and without lumbar stress fracture, and whether bone mineral density trajectories differed between groups during rehabilitation.

DESIGN

Cross-sectional and cohort.

METHODS

29 elite male fast bowlers received a post-season anteroposterior lumbar dual-energy X-ray absorptiometry scan and a lumbar magnetic resonance imaging scan to determine stress fracture status. Participants were invited for three additional scans across the 59 weeks post baseline or diagnosis of injury. Bone mineral density was measured at L1 - L4 and ipsilateral and contralateral L3 and L4 sites. Independent-sample t-tests determined baseline differences in bone mineral density and multilevel models were used to examine differences in bone mineral density trajectories over time between injured and uninjured participants.

RESULTS

17 participants with lumbar stress fracture had lower baseline bone mineral density at L1 - L4 (7.6 %, p = 0.034) and contralateral sites (8.8-10.4 %, p = 0.038-0.058) than uninjured participants. Bone mineral density at all sites decreased 1.9-3.0 % by 20-24 weeks before increasing to above baseline levels by 52 weeks post injury.

CONCLUSIONS

Injured fast bowlers had lower lumbar bone mineral density at diagnosis that decreased following injury and did not return to baseline until up to a year post-diagnosis. Localised maladaptation of bone mineral density may contribute to lumbar stress fracture. Bone mineral density loss following injury may increase risk of recurrence, therefore fast bowlers require careful management when returning to play.

A Higher Playing Standard, Bowling, and Intermittent Helmet Use Are Related to a Greater Odds of Injury or Concussion in Cricket

OBJECTIVE

To determine if playing position, a higher playing standard, and nonhelmet use are related to an increased odds of joint-specific injury and concussion in cricket.

DESIGN

Cross-sectional cohort.

PARTICIPANTS

Twenty-eight thousand one hundred fifty-two current or former recreational and high-performance cricketers registered on a national database were invited to participate in the Cricket Health and Wellbeing Study. Eligibility requirements were aged ≥18 years and played ≥1 cricket season.

INDEPENDENT VARIABLES

Main playing position (bowler/batter/all-rounder), playing standard (high-performance/recreational), and helmet use (always/most of the time/occasionally/never).

MAIN OUTCOME MEASURES

Cross-sectional questionnaire data included cricket-related injury (hip/groin, knee, ankle, shoulder, hand, back) resulting in ≥4 weeks of reduced exercise and self-reported concussion history. Crude and adjusted (adjusted for seasons played) odds ratios and 95% confidence interval (CIs) were estimated using logistic regression.

RESULTS

Of 2294 participants (59% current cricketers; 97% male; age 52 ± 15 years; played 29 ± 15 seasons; 62% recreational cricketers), 47% reported cricket-related injury and 10% reported concussion. Bowlers had greater odds of hip/groin [odds ratio (95% CI), 1.9 (1.0-3.3)], knee [2.0 (1.4-2.8)], shoulder [2.9 (1.8-4.5)], and back [2.8 (1.7-4.4)] injury compared with batters. High-performance cricketers had greater odds of injury and concussion than recreational cricketers. Wearing a helmet most of the time [2.0 (1.4-3.0)] or occasionally [1.8 (1.3-2.6)] was related to higher odds of self-reported concussion compared with never wearing a helmet. Concussion rates were similar in cricketers who always and never wore a helmet.

CONCLUSIONS

A higher playing standard and bowling (compared with batting) were associated with greater odds of injury. Wearing a helmet occasionally or most of the time was associated with higher odds of self-reported concussion compared with never wearing a helmet.

Bone health and asymmetry in elite female cricketers

The aim of this study is to determine if bone mineral density (BMD) and bone asymmetry differs between female cricket fast bowlers, spin bowlers and batters. BMD was determined at the total body, lumbar spine, and proximal femurs in 12 fast bowlers, 13 batters and 11 spin bowlers from pre-season DXA scans. High Z-scores at the total body, lumbar spine, and proximal femur were observed in all cricketers (mean Z-scores: +1.4 to +3.3) compared with a general age matched reference population. Fast bowlers had significantly greater BMD on the contralateral side of the lumbar spine compared with the ipsilateral side (p = 0.001, 5.9 - 12.1%). No asymmetry was found between hips in all groups. All cricket positions demonstrated high BMD at all measured sites. The lumbar spine of fast bowlers is asymmetric, with significantly greater BMD on the contralateral side of the spine, particularly at L4, possibly in response to the asymmetric lumbar loading patterns observed in bowling.HIGHLIGHTS Elite female cricketers demonstrate high BMD at total body, lumbar spine and proximal femur sites, regardless of playing position compared with a general age and ethnic group matched reference populationFast bowlers have greater BMD on the contralateral (opposite bowling arm) side of the lumbar spine compared with the ipsilateral side, while a symmetrical pattern was observed in spin bowlers and batters.No asymmetry in BMD or section modulus between hips was observed at any proximal femur site for any cricket position.

Results of a nationally implemented cardiac screening programme in elite cricket players in England and Wales

OBJECTIVES

We assessed the diagnostic yield and costs of an electrocardiogram-based national screening programme in elite cricket players and the incremental value of transthoracic echocardiography and periodic evaluation.

DESIGN

Cross-sectional study.

METHODS

Between 2008 and 2019, 1208 cricketers underwent screening with a health questionnaire, 12-lead electrocardiogram and cardiology consultation. Athletes with concerning findings underwent on-site transthoracic echocardiography and further investigations as necessary. In addition, despite a normal health questionnaire and electrocardiogram, 342 (28.3%) athletes had a transthoracic echocardiogram and 493 (40.8%) underwent repeat evaluations.

RESULTS

After initial evaluation, 47 (3.9%) athletes underwent on-site transthoracic echocardiography of whom 35 (2.8%) were referred for further evaluation. Four athletes (0.3%) were diagnosed with major cardiac conditions; hypertrophic cardiomyopathy (n = 1), arrhythmogenic cardiomyopathy (n = 1) and Wolff-Parkinson-White pattern (n = 2). Two athletes were identified with minor valvular abnormalities. Repeat evaluation of 493 athletes identified hypertrophic cardiomyopathy in a 22-year-old athlete, two years after his initial normal screening. During a follow-up of 5.8 ± 2.9 years no additional diagnoses or adverse cardiac events were reported. The cost of the electrocardiogram-based programme was £127,844, translating to £106 per athlete and £25,569 per major cardiac condition identified.Routine transthoracic echocardiography in 342 athletes identified two athletes with major cardiac conditions (bicuspid aortic valve with severe aortopathy and aortic regurgitation and an atrial septal defect associated with right ventricular volume overload) and 10 athletes with minor abnormalities.

CONCLUSIONS

An electrocardiogram-based national screening programme identified a major cardiac condition in 0.3% of athletes. Routine transthoracic echocardiography and periodic evaluation increased the diagnostic yield to 0.6%, at an incremental cost.

Observable player behaviours and playing performance following helmet strikes in elite cricket

OBJECTIVES

Investigate the observable player behaviours and features of both concussive (HS-C) and non-concussive (HS-NC) helmet strikes and describe their impact on playing performance.

METHODS

Elite male cricketers sustaining helmet strikes between the 2016 and 2018 seasons were identified by the England and Wales Cricket Board. Medical records identified players sustaining a concussion and those in whom concussion was excluded. Retrospective cohort analysis was performed on batting and bowling performance data available for these players in the 2 years prior to and 3 months post helmet strike. Video analysis of available incidents was conducted to describe the characteristics of the helmet strike and subsequent observable player behaviours. The HS-C and HS-NC cohorts were compared.

RESULTS

Data were available for 194 helmet strikes. 56 (29%) resulted in concussion. No significant differences were seen in playing performance in the 3 months post concussive helmet strike. However, a significant decline in batting performance was seen in this period in the HS-NC group (p<0.001).Video features signifying motor incoordination were most useful in identifying concussion post helmet strike, however, typical features suggesting transient loss of consciousness were not seen. Features such as a longer duration pause prior to the batsman resuming play and the level of concern shown by other players were also useful features.

CONCLUSION

HS-NC may be more significant for player performance than previously thought. Guidance for using video replay to identify concussion in cricket may need to be modified when compared with other field sports.

Lumbar Bone Mineral Adaptation: The Effect of Fast Bowling Technique in Adolescent Cricketers

INTRODUCTION

Localised bone mineral density (BMD) adaptation of the lumbar spine, particularly on the contralateral side to the bowling arm, has been observed in elite male cricket fast bowlers. No study has investigated this in adolescents, or the role of fast bowling technique on lumbar BMD adaptation. This study aims to investigate lumbar BMD adaptation in adolescent cricket fast bowlers, and its relationship with fast bowling technique.

METHODS

39 adolescent fast bowlers underwent antero-posterior DXA scan of their lumbar spine. Hip, lumbopelvic and thoracolumbar joint kinematics, and vertical ground reaction kinetics were determined using 3D motion capture and force plates. Significant partial (covariate: fat free mass) and bivariate correlations of the technique parameters with whole lumbar (L1-L4) BMD and BMD asymmetry (L3 and L4) were advanced as candidate variables for multiple stepwise linear regression.

RESULTS

Adolescent fast bowlers demonstrated high lumbar Z-Scores (+1.0; 95%CI: 0.7 - 1.4) and significantly greater BMD on the contralateral side of L3 (9.0%; 95%CI: 5.8 - 12.1%) and L4 (8.2%; 95%CI: 4.9 - 11.5%). Maximum contralateral thoracolumbar rotation and maximum ipsilateral lumbopelvic rotation in the period between back foot contact (BFC) and ball release (BR), as well as contralateral pelvic drop at front foot contact (FFC), were identified as predictors of L1-L4 BMD, explaining 65% of the variation. Maximum ipsilateral lumbopelvic rotation between BFC and BR, as well as ipsilateral lumbopelvic rotation and contralateral thoracolumbar side flexion at BR, were predictors of lumbar asymmetry within L3 and L4.

CONCLUSION

Thoracolumbar and lumbopelvic motion are implicated in the aetiology of the unique lumbar bone adaptation observed in fast bowlers whereas vertical ground reaction force, independent of body mass, was not. This may further implicate the osteogenic potential of torsional rather than impact loading in exercise-induced adaptation.

Detecting Injury Risk Factors with Algorithmic Models in Elite Women's Pathway Cricket

This exploratory retrospective cohort analysis aimed to explore how algorithmic models may be able to identify important risk factors that may otherwise not have been apparent. Their association with injury was then assessed with more conventional data models. Participants were players registered on the England and Wales Cricket Board women's international development pathway (n=17) from April 2018 to August 2019 aged between 14-23 years (mean 18.2±1.9) at the start of the study period. Two supervised learning techniques (a decision tree and random forest with traditional and conditional algorithms) and generalised linear mixed effect models explored associations between risk factors and injury. The supervised learning models did not predict injury (decision tree and random forest area under the curve [AUC] of 0.66 and 0.72 for conditional algorithms) but did identify important risk factors. The best-fitting generalised linear mixed effect model for predicting injury (Akaike Information Criteria [AIC]=843.94, conditional r-squared=0.58) contained smoothed differential 7-day load (P<0.001), average broad jump scores (P<0.001) and 20 m speed (P<0.001). Algorithmic models identified novel injury risk factors in this population, which can guide practice and future confirmatory studies can now investigate.

The impact of COVID-19 related disruption on injury rates in elite men's domestic cricket

This study aimed to investigate the impact of COVID-19 enforced prolonged training disruption and shortened competitive season, on in-season injury and illness rates. Injury incidence and percent proportion was calculated for the 2020 elite senior men's domestic cricket season and compared to a historical average from five previous regular seasons (2015 to 2019 inclusive). The injury profile for the shortened 2020 season was generally equivalent to what would be expected in a regular season, except for a significant increase in medical illness as a proportion of time loss (17% compared to historic average of 6%) and in-season days lost (9% compared to historic average of 3%) due to COVID-19 related instances (most notably precautionary isolation due to contact with a confirmed or suspected COVID-19 case). There was a significant increase in the proportion of in-season days lost to thigh injuries (24% compared to 9%) and a significant decrease in the proportion of days lost to hand (4% compared to 12%) and lumbar spine (7% compared to 21%) injuries. These findings enhance understanding of the impact prolonged period of training disruption and shortened season can have on cricket injuries and the challenges faced by practitioners under such circumstances.

Epidemiology of Hand Fractures and Dislocations in England and Wales Professional Cricketers

This study describes hand fracture and dislocation injuries in terms of anatomical distribution, incidence and impact on playing time in registered professional adult male players of all 18 First Class England and Wales County Cricket clubs over a five-year period from 2010-2014. Prospectively collected injury surveillance data for 1^st and 2^nd Team matches (Twenty20, One day and four-day) and training were analysed. There were 109 hand fractures and 53 dislocations. Hand injury was commonest during fielding (60%, 98/162) compared to batting, bowling or wicket-keeping. Exposed parts of the hand including tips of all digits, the index finger, thumb ray and little finger ray were most frequently injured with 78% (125/160) of all injuries where anatomical location was recorded. Match injury incidence for batsmen was highest in four-day matches (0.071 injuries per 1000 overs batted) but for other player roles it was highest in Twenty20 matches (0.587 per 1000 overs bowled). Player unavailability for selection to play was incurred in 82% (89/109) of hand fractures but only 47% (25/53) of dislocations. This study clarifies the hand fracture and dislocation injury burden for this population.

Physical inactivity and health inequality during coronavirus: a novel opportunity or total lockdown?

Government-restricted movement during the coronavirus pandemic in various countries around the world has led to rapid and fundamental changes in our health behaviour. As well as being at a higher risk of contracting and being hospitalised with COVID-19, the elderly, those with chronic disease and lower socioeconomic groups are also disproportionately affected by restriction of movement, further widening the physical activity health inequality. In this viewpoint we discuss the physiological sequelae of physical inactivity, and the additional burden of ageing and inflammation. We provide recommendations for public health promotion and interventions to try to mitigate the detrimental effects of physical inactivity and rebalance the health inequality.

The Potential for Transmission of Coronaviruses via Sports Equipment; A Cricket Case Study

A review of literature on the role of fomites in transmission of coronaviruses informed the development of a framework which was used to qualitatively analyse a cricket case study, where equipment is shared and passed around, and identify potential mitigation strategies. A range of pathways were identified that might in theory allow coronavirus transmission from an infected person to a non-infected person via communal or personal equipment fomites or both. Eighteen percent of potential fomite based interactions were found to be non-essential to play including all contact with another persons equipment. Six opportunities to interrupt the transmission pathway were identified, including the recommendation to screen participants for symptoms prior to play. Social distancing between participants and avoiding unnecessary surface contact provides two opportunities; firstly to avoid equipment exposure to infected respiratory droplets and secondly to avoid uninfected participants touching potential fomites. Hand sanitisation and equipment sanitisation provide two further opportunities by directly inactivating coronavirus. Preventing players from touching their mucosal membranes with their hands represents the sixth potential interruption. Whilst potential fomite transmission pathways were identified, evidence suggests that viral load will be substantially reduced during surface transfer. Mitigation strategies could further reduce potential fomites, suggesting that by comparison, direct airborne transmission presents the greater risk in cricket.

Cricket Fast Bowling Technique and Lumbar Bone Stress Injury

INTRODUCTION

Lumbar bone stress injuries (LBSI) are the most prevalent injury in cricket. Although fast bowling technique has been implicated in the etiology of LBSI, no previous study has attempted to prospectively analyze 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 noninjured bowlers in rear knee angle, rear hip angle, thoracolumbar side flexion angle, and thoracolumbar rotation angle at back foot contact; the front hip angle, pelvic tilt orientation, and lumbopelvic angle at front foot contact; and the thoracolumbar side flexion angle at ball release and the maximal front hip angle and ipsilateral pelvic drop orientation. A binary logistic model, consisting of rear hip angle at back foot contact and lumbopelvic angle at front foot contact, 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).

CONCLUSIONS

Lumbopelvic motion is implicated in the etiology of LBSI in fast bowling, with inadequate lumbopelvifemoral complex control as 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.

The Potential for Airborne Transmission of SARS-CoV-2 in Sport: A Cricket Case Study

A review of risk factors affecting airborne transmission of SARS-CoV-2 was synthesised into an 'easy-to-apply' visual framework. Using this framework, video footage from two cricket matches were visually analysed, one pre-COVID-19 pandemic and one 'COVID-19 aware' game in early 2020. The number of opportunities for one participant to be exposed to biological secretions belonging to another participant was recorded as an exposure, as was the estimated severity of exposure as defined from literature. Events were rated based upon distance between subjects, relative orientation of the subjects, droplet generating activity performed (e. g., talking) and event duration. In analysis we reviewed each risk category independently and the compound effect of an exposure i. e., the product of the scores across all categories. With the application of generic, non-cricket specific, social distancing recommendations and general COVID-19 awareness, the number of exposures per 100 balls was reduced by 70%. More impressive was the decrease in the most severe compound ratings (those with two or more categories scored with the highest severity) which was 98% and the reduction in exposures with a proximity <1 m, 96%. Analysis of the factors effecting transmission risk indicated that cricket was likely to present a low risk, although this conclusion was somewhat arbitrary omitting a comparison with a non-cricketing activity.

Narrative review of mental illness in cricket with recommendations for mental health support

Introduction

Epidemiology reporting within the cricketing medical literature has emerged over the past 2 years, with a focus on physical injuries. Despite mental health in elite sport gaining increasing recognition, few studies have addressed mental health symptoms and disorders within cricket. Recently, cricketers have been prominent in the mainstream media describing their lived experiences of mental illness. As a result, some have withdrawn from competition and suggested there is an unmet need for mental health services within the sport.

Objectives

(i) To appraise the existing evidence on mental health symptoms and disorders amongst cricketers. (ii) To provide guidance on shaping mental health research and services within cricket.

Design

A narrative review of the literature from inception of available databases until 26 July 2019, with analysis and recommendations.

Results

Five studies were included in this narrative review. Studies covered a range of mental health symptoms and disorders, including distress, anxiety, depression, sleep disturbance, suicide, adverse alcohol use, illicit drug use, eating disorders and bipolar disorder. Results indicated that cricketers are at high risk for distress, anxiety, depression and adverse alcohol use. When compared with the general population, cricketers are more likely to experience anxiety and depressive symptoms. Rates of suicide were proposed to be high for test cricketers. Overall, studies to date have been of low quality, demonstrating non-rigorous research methods. Some studies have relied on non-validated questionnaires to collect self-reported data on mental health symptoms and disorders, while others have presented biographical data obtained through searches of the media.

Conclusions

The results of this narrative review highlight the lack of evidence underpinning mental health services for athletes within cricket. We suggest the following recommendations for future research and practice: (i) normalising mental health symptoms and disorders; (ii) working with and helping vulnerable demographic segments within the target population; (iii) designing and implementing early recognition systems of mental health symptoms and disorders; (iv) addressing the mental health needs of cricketers on a population basis.

Injury and Player Availability in Women's International Pathway Cricket from 2015 to 2019

This 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.• The first study on an international women's cricket pathway, contributes to the empirical base for specific injury risks associated with the women's cricket game, which is an emerging research area for a developing sport.• Some of the findings may be a distinct feature of the women's cricket international pathway, highlighting potential opportunities for targeted prevention strategies.• With the upcoming development of an elite domestic structure these preliminary findings will provide a good starting point for physiotherapy and medical staff working in these contexts.

Injuries in England and Wales elite men's domestic cricket: A nine season review from 2010 to 2018

OBJECTIVES

This study primarily aimed to explore injury incidence rates in the three main domestic competition formats in England and Wales (First-Class, One-Day and Twenty20 [T20]). For the first time, the study also describes the epidemiology of elite men's domestic cricket injuries across nine seasons (2010-2018 inclusive).

DESIGN

Prospective cohort analysis.

METHODS

Injury incidence and prevalence from all injuries calculated according to the updated international consensus statement on injury surveillance in cricket, with statistical process control charts (SPC) used to detect trends in the data.

RESULTS

The average match injury incidence was 102 injuries/1000 days of play, with highest incidence in One-Day (254 injuries/1000 days of play), followed by T20 (136 injuries/1000 days of play) and First-Class Cricket (68 injuries/1000 days of play). Most match injuries were sustained during bowling (41.6 injuries/1000 days of play), followed by fielding (26.8 injuries/1000 days of play) and batting (22.3 injuries/1000 days of play). The thigh was the body area most commonly injured (7.4 injuries/100 players per season), with lumbar spine injuries the most prevalent (1.3% of players unavailable on any given day during the season). On average, 7.5% of players were unavailable on any given day during the domestic season when all injuries were considered (match and training). The SPC charts showed relatively consistent match injury incidence for all competitions, reproduced across all nine seasons.

CONCLUSION

These findings provide a robust empirical base for the extent of the injury problem in domestic cricket played in England and Wales, with similar injury profiles across the three formats.

Joint pain and osteoarthritis in former recreational and elite cricketers

BACKGROUND

Sport 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.

METHODS

The 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).

RESULTS

846 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.

CONCLUSIONS

Every 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.

Physical activity and health-related quality of life in former elite and recreational cricketers from the UK with upper extremity or lower extremity persistent joint pain: a cross-sectional study

OBJECTIVE

To evaluate and compare physical activity (PA) and health-related quality of life (HRQoL) in former elite and recreational cricketers with upper extremity (UE), lower extremity (LE) or no joint pain.

STUDY DESIGN

Cross-sectional cohort.

SETTING

Despite the high prevalence of joint pain in former athletes, the impact of UE pain and LE pain on PA and HRQoL and potential differences between former recreational and elite athletes are poorly understood.

PARTICIPANTS

703 former cricketers aged ≥18 years (mean age 58.7, SD 12.9, played an average of 30 (IQR 20-40) seasons, 72% of whom had played at a recreational level) were recruited through the Cricket Health and Wellbeing Study and met eligibility requirements (UE pain, LE pain or no joint pain (defined as pain on most days of the past month)).

PRIMARY AND SECONDARY OUTCOMES

The International Physical Activity Questionnaire-Short Form collected weekly metabolic equivalents (METS), while the Short-Form 8 collected physical (PCS) and mental (MCS) component scores. Kruskal-Wallis tests with Dunn's post-hoc and multivariable linear regressions were performed.

RESULTS

Weekly METS were similar in former cricketers with UE pain (median (IQR) 2560 (722-4398)), LE pain (2215 (527-3903)) and no pain (2449 (695-4203), p=0.39). MCS were similar between groups (UE pain 56.0 (52.1-60.0); LE pain 55.2 (51.1-59.4); no pain 54.7 (50.7-58.7), p=0.38). PCS were more impaired in former cricketers with UE pain (49.8 (44.9-54.8)) or LE pain (46.7 (41.0-51.9)) compared with no pain (54.2 (51.5-56.9), p<0.0001). Former cricketers with LE pain reported worse PCS than those with UE pain (p=0.04). Similar relationships were observed in former elite and recreational cricketers.

CONCLUSION

Despite impaired physical components of HRQoL in former cricketers with UE pain or LE pain, pain was not related to PA levels or mental components of HRQoL. Physical components of HRQoL were most impaired in those with LE pain, and findings were similar among former elite and recreational cricketers.

Lumbar bone mineral asymmetry in elite cricket fast bowlers

PURPOSE

Bone responds to mechanical loading by increasing bone mineral density (BMD) and/or bone area to enhance bone strength at the site of the greatest strain. Such localised adaptation has not been demonstrated at the spine. The aim of this study is to determine if BMD and/or bone mineral content (BMC) differs between dominant (ipsilateral to bowling/throwing arm) and non-dominant sides of the vertebrae in cricket fast bowlers, and whether this asymmetry differs according to stress fracture or disc injury history. A further aim was to determine if regional BMD and BMC in the lumbar spine differ between fast bowlers, other cricketers, rugby players and non-active controls, to highlight the site-specific response of lumbar vertebra to unilateral activity.

METHODS

23 fast bowlers, 14 other cricketers, 22 rugby players and 20 controls underwent an antero-posterior (AP) and lateral DXA scans of their lumbar spine to assess BMD, BMC and area. A custom analysis measured BMD and BMC of the dominant and non-dominant sides (lateral 33%) of the AP lumbar spine. BMD and BMC were compared between groups, injury status, vertebrae and sides using ANOVA.

RESULTS

Analysis of medical records showed that 6 fast bowlers had a history of lumbar stress fracture. Significantly greater BMD and BMC was found in the L4 non-dominant vertebra compared with the dominant vertebra in fast bowlers. BMD and BMC differed significantly according to vertebra, side and group, with fast bowlers having significantly greater BMD and BMC at the L3 and L4 non-dominant vertebra compared with other groups (L3: 13.3%-45.3%, L4: 15.7%-44.0%) compared with other groups. Fast bowlers who never suffered lumbar stress fracture had 3.6% and 1.7% greater BMD in the dominant and non-dominant sides of lumbar vertebrae respectively compared with those who did suffer lumbar stress fracture, but evidence of this was weaker (P = 0.08).

CONCLUSION

The lumbar spine responds to a unique unilateral high loading activity through site-specific increased bone mass at the site of most strain. Fast bowlers had increased lumbar BMD, particularly on the non-dominant side of L4, although this adaptation was less marked in those with history of lumbar stress fracture. Site-specific low bone mineral density within the lumbar side may be implicated in the aetiology of lumbar stress fracture.

Incidence and prevalence of lumbar stress fracture in English County Cricket fast bowlers, association with bowling workload and seasonal variation

OBJECTIVES

Since much of the previous epidemiological research into lumbar stress fracture was conducted, there has been a marked increase in the amount of cricket being played. The aims were to determine the incidence and prevalence of lumbar stress fracture in English County Cricket fast bowlers between 2010 and 2016, determine the association with match bowling workload and observe seasonal variation in workload and injury.

METHODS

Lumbar stress fracture incidence and prevalence rates were calculated using new international methods for epidemiology in 368 professional English fast bowlers from 2010 to 2016. Workload variables were compared between lumbar stress fracture case and non-injured control groups, before entry in a logistic regression.

RESULTS

Fifty-seven lumbar stress fractures (mean age 22.81) were reported. Injury was most common in July and September. Match incidence was 0.16 lumbar stress fractures per 10 000 deliveries, annual incidence was 2.46 lumbar stress fractures per 100 fast bowlers and annual prevalence of lumbar stress fractures was 1.67% of squad days. Significant workload variables were observed between cases and controls. A peak 7-day workload of greater than 234 deliveries significantly increased the odds of sustaining a lumbar stress fracture 11-fold compared with bowling fewer than 197 deliveries.

CONCLUSION

Lumbar stress fractures are common in young fast bowlers possibly due to immaturity of the lumbar spine. The condensed early and late-season schedule may be causing periods of overuse, resulting in an increase in incidence of lumbar stress fracture. Reduction of workload in young fast bowlers is needed to reduce incidence.

Physical activity in former elite cricketers and strategies for promoting physical activity after retirement from cricket: a qualitative study

OBJECTIVES

The health benefits of professional sport dissipate after retirement unless an active lifestyle is adopted, yet reasons for adopting an active or inactive lifestyle after retirement from sport are poorly understood. Elite cricket is all-encompassing, requiring a high volume of activity and unique physical demands. We aimed to identify influences on physical activity behaviours in active and insufficiently active former elite cricketers and provide practical strategies for promoting physical activity after cricket retirement.

DESIGN

18 audio-recorded semistructured telephone interviews were performed. An inductive thematic approach was used and coding was iterative and data-driven facilitated by NVivo software. Themes were compared between sufficiently active and insufficiently active participants.

SETTING

All participants formerly played professional cricket in the UK.

PARTICIPANTS

Participants were male, mean age 57±11 (range 34-77) years, participated in professional cricket for 12±7 seasons and retired on average 23±9 years previously. Ten participants (56%) were classified as sufficiently active according to the UK Physical Activity Guidelines (moderate-intensity activity ≥150 min per week or vigorous-intensity activity ≥75 min per week). Eight participants did not meet these guidelines and were classified as insufficiently active.

RESULTS

Key physical activity influences were time constraints, habit formation, intrinsic and extrinsic motivation, physical activity preferences, pain/physical impairment and cricket coaching. Recommendations for optimising physical activity across the lifespan after cricket retirement included; prioritise physical activity, establish a physical activity plan prior to cricket retirement and don't take a break from physical activity, evaluate sources of physical activity motivation and incorporate into a physical activity plan, find multiple forms of satisfying physical activity that can be adapted to accommodate fluctuations in physical capabilities across the lifespan and coach cricket.

CONCLUSIONS

Physically active and less active retired cricketers shared contrasting attributes that informed recommendations for promoting a sustainable, physically active lifestyle after retirement from professional cricket.

Common attributes in retired professional cricketers that may enhance or hinder quality of life after retirement: a qualitative study

OBJECTIVES

Retired professional cricketers shared unique experiences and may possess specific psychological attributes with potential to influence quality of life (QOL). Additionally, pain and osteoarthritis can be common in retired athletes which may negatively impact QOL. However, QOL in retired athletes is poorly understood. This study explores the following questions from the personal perspective of retired cricketers: How do retired cricketers perceive and experience musculoskeletal pain and function in daily life? Are there any psychological attributes that might enhance or hinder retired cricketers' QOL?

DESIGN

A qualitative study using semistructured interviews, which were subject to inductive, thematic analysis. A data-driven, iterative approach to data coding was employed.

SETTING

All participants had lived and played professional cricket in the UK and were living in the UK or abroad at the time of interview.

PARTICIPANTS

Eighteen male participants, aged a mean 57±11 (range 34-77) years had played professional cricket for a mean 12±7 seasons and had been retired from professional cricket on average 23±9 years.

RESULTS

Fifteen participants reported pain or joint difficulties and all but one was satisfied with their QOL. Most retired cricketers reflected on experiences during their cricket career that may be associated with the psychological attributes that these individuals shared, including resilience and a positive attitude. Additional attributes included a high sense of body awareness, an ability to self-manage pain and adapt lifestyle choices to accommodate physical limitations. Participants felt fortunate and proud to have played professional cricket, which may have further contributed to the high QOL in this group of retired cricketers.

CONCLUSIONS

Most retired cricketers in this study were living with pain or joint difficulties. Despite this, all but one was satisfied or very satisfied with their QOL. This may be partly explained by the positive psychological attributes that these retired cricketers shared.

Dopamine/noradrenaline reuptake inhibition in women improves endurance exercise performance in the heat

Catecholamine reuptake inhibition improves the performance of male volunteers exercising in warm conditions, but sex differences in thermoregulation, circulating hormones, and central neurotransmission may alter this response. With local ethics committee approval, nine physically active women (mean ± SD age 21 ± 2 years; height 1.68 ± 0.08 m; body mass 64.1 ± 6.0 kg; VO_2peak 51 ± 7 mL/kg/min) were recruited to examine the effect of pre-exercise administration of Bupropion (BUP; 4 × 150 mg) on prolonged exercise performance in a warm environment. Participants completed a VO_2peak test, two familiarization trials, and two randomized, double-blind experimental trials. All trials took place during the first 10 days of the follicular phase of the menstrual cycle. Participants cycled for 1 h at 60% VO_2peak followed by a 30-min performance test. Total work done was greater during the BUP trial (291 ± 48 kJ) than the placebo trial (269 ± 46 kJ, P = 0.042, d = 0.497). At the end of the performance test, core temperature was higher on the BUP trial (39.5 ± 0.4 °C) than on the placebo trial (39.2 ± 0.6 °C, P = 0.021; d = 0.588), as was heart rate (185 ± 9 vs 179 ± 13, P = 0.043; d = 0.537). The results indicate that during the follicular phase of the menstrual cycle, an acute dosing protocol of BUP can improve self-regulated performance in warm conditions.

International consensus statement on injury surveillance in cricket: a 2016 update

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.

Creatine ingestion augments dietary carbohydrate mediated muscle glycogen supercompensation during the initial 24 h of recovery following prolonged exhaustive exercise in humans

Muscle glycogen availability can limit endurance exercise performance. We previously demonstrated 5 days of creatine (Cr) and carbohydrate (CHO) ingestion augmented post-exercise muscle glycogen storage compared to CHO feeding alone in healthy volunteers. Here, we aimed to characterise the time-course of this Cr-induced response under more stringent and controlled experimental conditions and identify potential mechanisms underpinning this phenomenon. Fourteen healthy, male volunteers cycled to exhaustion at 70 % VO_2peak. Muscle biopsies were obtained at rest immediately post-exercise and after 1, 3 and 6 days of recovery, during which Cr or placebo supplements (20 g day⁻¹) were ingested along with a prescribed high CHO diet (37.5 kcal kg body mass⁻¹ day⁻¹, >80 % calories CHO). Oral-glucose tolerance tests (oral-GTT) were performed pre-exercise and after 1, 3 and 6 days of Cr and placebo supplementation. Exercise depleted muscle glycogen content to the same extent in both treatment groups. Creatine supplementation increased muscle total-Cr, free-Cr and phosphocreatine (PCr) content above placebo following 1, 3 and 6 days of supplementation (all P < 0.05). Creatine supplementation also increased muscle glycogen content noticeably above placebo after 1 day of supplementation (P < 0.05), which was sustained thereafter. This study confirmed dietary Cr augments post-exercise muscle glycogen super-compensation, and demonstrates this occurred during the initial 24 h of post-exercise recovery (when muscle total-Cr had increased by <10 %). This marked response ensued without apparent treatment differences in muscle insulin sensitivity (oral-GTT, muscle GLUT4 mRNA), osmotic stress (muscle c-fos and HSP72 mRNA) or muscle cell volume (muscle water content) responses, such that another mechanism must be causative.

Stress fracture injury in female endurance athletes in the United Kingdom: A 12-month prospective study

Studies of stress fracture (SF) incidence are limited in number and geographical location; this study determined the incidence of SF injury in female endurance athletes based in the United Kingdom. A total of 70 athletes aged between 18 and 45 years were recruited and prospectively monitored for 12 months. Questionnaires at baseline and 12 months assessed SF, menstrual and training history, eating psychopathology, and compulsive exercise. Peak lower leg muscle strength was assessed in both legs using an isometric muscle rig. Bone mineral density (BMD) of total body, spine, hip, and radius was assessed using dual X-ray absorptiometry. Among the 61 athletes who completed the 12-month monitoring, two sustained a SF diagnosed by magnetic resonance imaging, giving an incidence rate (95% confidence intervals) of 3.3 (0.8, 13.1) % of the study population sustaining a SF over 12 months. The SF cases were 800 m runners aged 19 and 22 years, training on average 14.2 h a week, eumenorrheic with no history of menstrual dysfunction. Case 1 had a higher than average energy intake and low eating psychopathology and compulsive exercise scores, while the reverse was true in case 2. BMD in both cases was similar to mean values in the non-SF group. The incidence of SF in our female endurance athlete population based in the United Kingdom was 3.3%, which is lower than previously reported. Further work is needed to confirm the current incidence of SF and evaluate the associated risk factors.

Bone geometry according to menstrual function in female endurance athletes

Athletes have higher bone mineral density (BMD) relative to nonathletes. In amenorrheic athletes BMD may be compromised by estrogen deficiency, but it is unknown whether this is accompanied by structural differences. We compared femoral neck bone geometry and density of a-/oligomenorrheic athletes (AAs), eumenorrheic athletes (EAs), and eumenorrheic controls (ECs). We recruited 156 women: (68 endurance athletes and 88 controls). Femoral neck BMD, section modulus (Z), and width were measured using dual-energy X-ray absorptiometry. Menstrual function was assessed by questionnaire and classified as EA (≥10 periods/year) or AA (≤9 periods/year): 24 athletes were AA and 44 EA. Femoral neck BMD was significantly higher in EA than AA (8 %, difference) and EC (11 % difference): mean [SE] 1.118 [0.015], 1.023 [0.020] and 0.999 [0.014] g cm(-2), respectively; p < 0.001. Z was significantly higher in EA than EC (11 % difference): EA 667 [19], AA 625 [21], and EC 592 [10] cm(3); p < 0.001. Femoral neck width did not differ between groups. All differences persisted after adjustment for height, age, and body mass. The higher femoral neck Z and BMD in athletes, despite similar width, may indicate that exercise-related bone gains are endosteal rather than periosteal. Athletes with amenorrhea had smaller increments in bone mass rather than structural adaptation. The maintained femoral neck width in controls may be an adaptive mechanism to conserve bone strength in bending despite inactivity-related bone decrement.

Risk factors for stress fracture in female endurance athletes: a cross-sectional study

OBJECTIVE

To identify psychological and physiological correlates of stress fracture in female endurance athletes.

DESIGN

A cross-sectional design was used with a history of stress fractures and potential risk factors assessed at one visit.

METHODS

Female-endurance athletes (58 runners and 12 triathletes) aged 26.0±7.4 years completed questionnaires on stress fracture history, menstrual history, athletic training, eating psychopathology and exercise cognitions. Bone mineral density, body fat content and lower leg lean tissue mass (LLLTM) were assessed using dual-x-ray absorptiometry. Variables were compared between athletes with a history of stress fracture (SF) and those without (controls; C) using χ&sup2;, analysis of variance and Mann-Whitney U tests.

RESULTS

Nineteen (27%) athletes had previously been clinically diagnosed with SFs. The prevalence of current a/oligomenorrhoea and past amenorrhoea was higher in SF than C (p=0.008 and p=0.035, respectively). SF recorded higher global scores on the eating disorder examination questionnaire (p=0.049) and compulsive exercise test (p=0.006) and had higher LLLTM (p=0.029) compared to C. These findings persisted with weight and height as covariates. In multivariate logistic regression, compulsive exercise, amenorrhoea and LLLTM were significant independent predictors of SF history (p=0.006, 0.009 and 0.035, respectively).

CONCLUSIONS

Eating psychopathology was associated with increased risk of SF in endurance athletes, but this may be mediated by menstrual dysfunction and compulsive exercise. Compulsive exercise, as well as amenorrhoea, is independently related to SF risk.

Disassociation between the effects of amino acids and insulin on signaling, ubiquitin ligases, and protein turnover in human muscle

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-(13)C]leucine [i.e., muscle protein synthesis (MPS), P < 0.01] without affecting the rate of leg protein breakdown (LPB; appearance of d(5)-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 Ser(473) and p70(S6k) Thr(389) increased concomitantly with insulin, but whereas raising insulin to 30 mU/l increased the phosphorylation of mTOR Ser(2448), 4E-BP1 Thr(37/46), or GSK3beta Ser(9) and decreased that of eEF2 Thr(56), 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.

Disuse atrophy and exercise rehabilitation in humans profoundly affects the expression of genes associated with the regulation of skeletal muscle mass

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.

Low intensity exercise in humans accelerates mitochondrial ATP production and pulmonary oxygen kinetics during subsequent more intense exercise

We undertook this study to determine whether low intensity exercise (55 % (O2,max) would significantly alter the metabolic and ventilatory responses observed during 10 min of subsequent moderate intensity exercise (75 % (O2,max). By executing this work, we hoped to further our understanding of the mechanisms that limit mitochondrial ATP production at the onset of exercise. Seven healthy human subjects performed 10 min of moderate intensity exercise in the presence and absence of 10 min of low intensity exercise, which preceded the moderate intensity exercise by 3 min. Muscle biopsy samples were obtained from the vastus lateralis at pre-determined time points and oxygen consumption kinetics were determined at rest and during low and moderate intensity exercise. Following low intensity exercise and 3 min of passive recovery, muscle lactate and acetylcarnitine concentrations were elevated above basal levels, but (O2) had returned to the resting rate. When moderate intensity exercise was preceded by low intensity exercise, there was a significant sparing of phosphocreatine (PCr, approximately 25 %, P < 0.05) and reductions in glucose 6-phosphate (G-6-P, approximately 50 %, P < 0.05) and lactate (approximately 50 %, P < 0.05) accumulation during the first minute of moderate intensity exercise. No differences were observed after 10 min of moderate intensity exercise. The (O2) on-kinetic response over the first minute of moderate intensity exercise was accelerated when preceded by low intensity exercise. Collectively, our results suggest the lag in the oxidative ATP delivery at the onset of moderate intensity exercise can be overcome by prior low intensity exercise. Furthermore, our findings support the view that this lag is at least in part attributable to a limitation in acetyl group delivery/availability at the onset of exercise, rather than delayed oxygen supply.