Prognostic value of ultrasound tissue characterisation for a recurrence of mid-portion Achilles tendinopathy in military service members: a prospective cohort study.

INTRODUCTION: Tendon structure in mid-portion Achilles tendinopathy (mid-AT) appears poorly associated with symptoms. Yet, degenerative tendon changes on imaging have been associated with an increased risk of mid-AT. We aimed to investigate the prognostic value of ultrasound tissue characterisation (UTC) for a mid-AT recurrence in service members reporting to be recovered following standard care. METHODS: Mid-portion aligned fibrillar structure was quantified post-treatment in 37 participants. Recurrences were determined after 1 year of follow-up, based on self-perceived recurrence (yes/no) combined with a decrease in post-treatment Victorian Institute of Sports Assessment-Achilles score of at least the minimal important change of 7 points. Receiver operating characteristic curve analyses were used to determine a threshold for dichotomisation of outcomes for aligned fibrillar structure (normal representation/under-representation). Using multivariable logistic regression, the association between a mid-AT recurrence (yes/no) and the dichotomised aligned fibrillar structure was determined. RESULTS: Eight participants (22%) experienced a recurrence. The threshold for aligned fibrillar structure was set at 73.2% (95% CI: 69.4% to 77.8%) according to Youden's index. Values below this threshold were significantly associated with a mid-AT recurrence (odds ratio (OR) 9.7, 95% CI: 1.007 to 93.185). The OR for a mid-AT recurrence was 1.1 (95% CI: 1.002 to 1.150) for each additional month of symptom duration. The explained variance of our multivariable logistic regression model was 0.423; symptom duration appeared to be a better predictor than aligned fibrillar structure. CONCLUSIONS: This study identified mid-portion aligned fibrillar structure and symptom duration as potential prognostic factors for a mid-AT recurrence in military service members. The threshold for aligned fibrillar structure of 73.2% can guide preventative interventions (eg, training load adjustments or additional tendon load programmes) aiming to improve tendon structure to minimise the future recurrence risk. TRIAL REGISTRATION NUMBER: https://www.toetsingonline.nl/to/ccmo_search.nsf/Searchform?OpenForm, file number ToetsingOnline NL69527.028.19.

Victorian Institute of Sport Assessment-Achilles thresholds for minimal important change and return to presymptom activity level in active soldiers with mid-portion Achilles tendinopathy.

INTRODUCTION: Mid-portion Achilles tendinopathy (mid-AT) is common in soldiers, significantly impacting activity levels and operational readiness. Currently, Victorian Institute of Sport Assessment-Achilles (VISA-A) represents the gold standard to evaluate pain and function in mid-AT. Our objective was to estimate VISA-A thresholds for minimal important change (MIC) and patient-acceptable symptom state for return to the presymptom activity level (PASS-RTA), in soldiers treated with a conservative programme for mid-AT. METHODS: A total of 40 soldiers (40 unilateral symptomatic Achilles tendons) were included in this prospective cohort study. Pain and function were evaluated using VISA-A. Self-perceived recovery was assessed with the Global Perceived Effect scale. The predictive modelling method (MIC-predict) was used to estimate MIC VISA-A post-treatment (after 26 weeks) and after 1 year of follow-up. The post-treatment PASS-RTA VISA-A was estimated using receiver operating characteristic statistics. The PASS-RTA was determined by calculating Youden's index value closest to 1. RESULTS: The adjusted MIC-predict was 6.97 points (95% CI 4.18 to 9.76) after 26 weeks and 7.37 points (95% CI 4.58 to 10.2) after 1 year of follow-up post-treatment.The post-treatment PASS-RTA was 95.5 points (95% CI 92.2 to 97.8). CONCLUSIONS: A VISA-A change score of 7 points, post-treatment and at 1 year of follow-up, can be considered a minimal within-person change over time, above which soldiers with mid-AT perceive themselves importantly changed. Soldiers consider their symptoms to be acceptable for return to their presymptom activity level at a post-treatment VISA-A score of 96 points or higher. TRIAL REGISTRATION NUMBER: NL69527.028.19.

Poor association between tendon structure and self-reported symptoms following conservative management in active soldiers with mid-portion Achilles tendinopathy.

INTRODUCTION: Mid-portion Achilles tendinopathy (mid-AT) is currently the preferred term for persistent Achilles tendon pain, defined as located 2-7 cm proximal to the calcaneus, and with loss of function related to mechanical loading. Histologically, mid-AT is considered to represent a degenerative condition. Therefore, monitoring of tendon structure additional to pain and function may be warranted, to prevent progression of degeneration or even tendon rupture. The aim of this study was to determine the association between pain and function, relative to the Achilles tendon structure, in soldiers treated with a conservative programme for mid-AT. METHODS: A total of 40 soldiers (40 unilateral symptomatic tendons) were included in this study. Pain and function were evaluated with the Victorian Institute of Sports Assessment -Achilles (VISA-A) questionnaire. Tendon structure was quantified using ultrasound tissue characterisation (UTC). We quantified both the Achilles tendon mid-portion (2-7 cm) and the area of maximum degeneration (AoMD) within the tendon mid-portion. VISA-A and UTC measurements were taken at baseline and after 26 weeks of follow-up. Spearman's rho was used to determine the correlation between VISA-A and UTC. Correlations were calculated for baseline, follow-up and change score values. RESULTS: Negligible correlations were found for all analyses, ranging from -0.173 to 0.166 between mid-portion tendon structure and VISA-A, and from -0.137 to 0.150 between AoMD and VISA-A. While VISA-A scores improved, on average, from 59.4 points at baseline to 93.5 points at follow-up, no detectable improvement in aligned fibrillar structure was observed in our population. CONCLUSION: Pain and function are poorly associated with Achilles tendon structure in soldiers treated with a conservative programme for mid-AT. Therefore, we advise clinicians to use great caution in communicating relationships between both clinical entities. TRIAL REGISTRATION NUMBER: NL69527.028.19.

Supervised exercise after oesophageal cancer surgery: the PERFECT multicentre randomized clinical trial.

BACKGROUND: This study investigated whether a supervised exercise programme improves quality of life (QoL), fatigue and cardiorespiratory fitness in patients in the first year after oesophagectomy. METHODS: The multicentre PERFECT trial randomly assigned patients to an exercise intervention (EX) or usual care (UC) group. EX patients participated in a 12-week moderate- to high-intensity aerobic and resistance exercise programme supervised by a physiotherapist. Primary (global QoL, QoL summary score) and secondary (QoL subscales, fatigue and cardiorespiratory fitness) outcomes were assessed at baseline, 12 and 24 weeks and analysed as between-group differences using either linear mixed effects models or ANCOVA. RESULTS: A total of 120 patients (mean(s.d.) age 64(8) years) were included and randomized to EX (61 patients) or UC (59 patients). Patients in the EX group participated in 96 per cent (i.q.r. 92-100 per cent) of the exercise sessions and the relative exercise dose intensity was high (92 per cent). At 12 weeks, beneficial EX effects were found for QoL summary score (3.5, 95 per cent c.i. 0.2 to 6.8) and QoL role functioning (9.4, 95 per cent c.i. 1.3 to 17.5). Global QoL was not statistically significant different between groups (3.0, 95 per cent c.i. -2.2 to 8.2). Physical fatigue was lower in the EX group (-1.2, 95 per cent c.i. -2.6 to 0.1), albeit not significantly. There was statistically significant improvement in cardiorespiratory fitness following EX compared with UC (peak oxygen uptake (1.8 ml/min/kg, 95 per cent c.i. 0.6 to 3.0)). After 24 weeks, all EX effects were attenuated. CONCLUSIONS: A supervised exercise programme improved cardiorespiratory fitness and aspects of QoL. TRIAL REGISTRATION: Dutch Trial Register NTR 5045 (www.trialregister.nl/trial/4942).

The prognostic value of the hamstring outcome score to predict the risk of hamstring injuries.

OBJECTIVES: Hamstring injuries are common among soccer players. The hamstring outcome score (HaOS) might be useful to identify amateur players at risk of hamstring injury. Therefore the aims of this study were: To determine the association between the HaOS and prior and new hamstring injuries in amateur soccer players, and to determine the prognostic value of the HaOS for identifying players with or without previous hamstring injuries at risk of future injury. DESIGN: Cohort study. METHODS: HaOS scores and information about previous injuries were collected at baseline and new injuries were prospectively registered during a cluster-randomized controlled trial involving 400 amateur soccer players. Analysis of variance and t-tests were used to determine the association between the HaOS and previous and new hamstring injury, respectively. Logistic regression analysis indicated the prognostic value of the HaOS for predicting new hamstring injuries. RESULTS: Analysis of data of 356 players indicated that lower HaOS scores were associated with more previous hamstring injuries (F=17.4; p=0.000) and that players with lower HaOS scores sustained more new hamstring injuries (T=3.59, df=67.23, p=0.001). With a conventional HaOS score cut-off of 80%, logistic regression models yielded a probability of hamstring injuries of 11%, 18%, and 28% for players with 0,1, or 2 hamstring injuries in the previous season, respectively. CONCLUSIONS: The HaOS is associated with previous and future hamstring injury and might be a useful tool to provide players with insight into their risk of sustaining a new hamstring injury risk when used in combination with previous injuries.

In training for a marathon: Runners and running-related injury prevention.

OBJECTIVE: To investigate which preventive measures runners use when preparing for a half- or full-marathon and whether the use of these measures at baseline and during the preparation-period differs between runners who sustained no/non-substantial running-related injuries (NSIRs) or substantial running-related injuries (SIRs). DESIGN: Prospective cohort study. SETTING: 16-week period before the Utrecht Marathon. PARTICIPANTS: Runners who subscribed for the half- or full-marathon. MAIN OUTCOME MEASURES: The occurrence of RRIs was registered every 2-weeks, using the Dutch version of the Oslo Sport Trauma Research Center (OSTRC) questionnaire on Health Problems. The OSTRC was used to differentiate between runners with SIRs (question 2/3 score>12) and NSIRs (question 2/3 score<13). The use of different preventive measures, was registered every 4-weeks. RESULTS: 51.6% of the runners reported at least one RRI in the 12-months prior to this study (history of RRIs). The SIRs with a history of RRIs more often asked for running shoe advice than NSIRs with a history of RRIs (67.9%vs43.4%, P < 0.05); 18.9% of the SIRs with a history of RRIs used supportive materials for knee and/or ankle versus 0% of NSIRs with a history of RRIs (P < 0.05). CONCLUSION: SIRs with a history of RRIs might be using their preventive measures for symptom reduction or secondary prevention.

Multicentre randomized clinical trial of inspiratory muscle training versus usual care before surgery for oesophageal cancer.

BACKGROUND: Up to 40 per cent of patients undergoing oesophagectomy develop pneumonia. The aim of this study was to assess whether preoperative inspiratory muscle training (IMT) reduces the rate of pneumonia after oesophagectomy. METHODS: Patients with oesophageal cancer were randomized to a home-based IMT programme before surgery or usual care. IMT included the use of a flow-resistive inspiratory loading device, and patients were instructed to train twice a day at high intensity (more than 60 per cent of maximum inspiratory muscle strength) for 2 weeks or longer until surgery. The primary outcome was postoperative pneumonia; secondary outcomes were inspiratory muscle function, lung function, postoperative complications, duration of mechanical ventilation, length of hospital stay and physical functioning. RESULTS: Postoperative pneumonia was diagnosed in 47 (39·2 per cent) of 120 patients in the IMT group and in 43 (35·5 per cent) of 121 patients in the control group (relative risk 1·10, 95 per cent c.i. 0·79 to 1·53; P = 0·561). There was no statistically significant difference in postoperative outcomes between the groups. Mean(s.d.) maximal inspiratory muscle strength increased from 76·2(26·4) to 89·0(29·4) cmH2 O (P < 0·001) in the intervention group and from 74·0(30·2) to 80·0(30·1) cmH2 O in the control group (P < 0·001). Preoperative inspiratory muscle endurance increased from 4 min 14 s to 7 min 17 s in the intervention group (P < 0·001) and from 4 min 20 s to 5 min 5 s in the control group (P = 0·007). The increases were highest in the intervention group (P < 0·050). CONCLUSION: Despite an increase in preoperative inspiratory muscle function, home-based preoperative IMT did not lead to a decreased rate of pneumonia after oesophagectomy. Registration number: NCT01893008 (https://www.clinicaltrials.gov).

The preventive effect of the bounding exercise programme on hamstring injuries in amateur soccer players: the design of a randomized controlled trial.

BACKGROUND: Hamstring injuries are the most common muscle injury in amateur and professional soccer. Most hamstring injuries occur in the late swing phase, when the hamstring undergoes a stretch-shortening cycle and the hamstring does a significant amount of eccentric work. The incidence of these injuries has not decreased despite there being effective injury prevention programmes focusing on improving eccentric hamstring strength. As this might be because of poor compliance, a more functional injury prevention exercise programme that focuses on the stretch-shortening cycle might facilitate compliance. In this study, a bounding exercise programme consisting of functional plyometric exercises is being evaluated. METHODS: A cluster-randomized controlled trial (RCT). Male amateur soccer teams (players aged 18-45 years) have been randomly allocated to intervention and control groups. Both groups are continuing regular soccer training and the intervention group is additionally performing a 12-week bounding exercise programme (BEP), consisting of a gradual build up and maintenance programme for the entire soccer season. The primary outcome is hamstring injury incidence. Secondary outcome is compliance with the BEP during the soccer season and 3 months thereafter. DISCUSSION: Despite effective hamstring injury prevention programmes, the incidence of these injuries remains high in soccer. As poor compliance with these programmes may be an issue, a new plyometric exercise programme may encourage long-term compliance and is expected to enhance sprinting and jumping performance besides preventing hamstring injuries. TRIAL REGISTRATION: NTR6129 . Retrospectively registered on 1 November 2016.

Hip muscle strength is decreased in middle-aged recreational male athletes with midportion Achilles tendinopathy: A cross-sectional study.

OBJECTIVE: Investigating differences in hip muscle strength between athletes with Achilles tendinopathy (AT) and asymptomatic controls. DESIGN: Cross-sectional case-control study. SETTING: Sports medical center. PARTICIPANTS: Twelve recreational male athletes with mid-portion AT and twelve matched asymptomatic controls. OUTCOME MEASURES: Isometric strength of the hip abductors, external rotators, and extensors was measured using a handheld dynamometer. Functional hip muscle performance was evaluated with the single-leg squat. The Victorian Institute of Sport Assessment-Achilles (VISA-A) questionnaire was completed to determine clinical severity of symptoms. RESULTS: Compared to controls, participants with AT demonstrated 28.9% less isometric hip abduction strength (p = 0.012), 34.2% less hip external rotation strength (p = 0.010), and 28.3% less hip extension strength (p = 0.034) in the injured limb. Similar differences were found for the non-injured limb (26.7-41.8%; p < 0.03). No significant differences were found in functional hip muscle performance between the injured and non-injured limb or between the groups, and no significant correlation was found between hip muscle strength and VISA-A scores. CONCLUSION: Recreational male athletes with chronic mid-portion AT demonstrated bilateral weakness of hip abductors, external rotators, and extensors compared to their asymptomatic counterparts. These findings suggest that hip muscle strength may be important in the assessment and rehabilitation of those with AT.

No psychological distress in sportsmen aged 45 years and older after cardiovascular screening, including cardiac CT: The Measuring Athlete's Risk of Cardiovascular events (MARC) study.

BACKGROUND: Psychological distress caused by cardiovascular pre-participation screening (PPS) may be a reason not to implement a PPS program. We assessed the psychological impact of PPS, including cardiac computed tomography (CT), in 318 asymptomatic sportsmen aged ≥45 years. METHODS: Coronary artery disease (CAD) was defined as a coronary artery calcium score ≥100 Agatson units and/or ≥50% luminal stenosis on contrast-enhanced cardiac CT. Psychological impact was measured with the Impact of Event Scale (IES) (seven items) on a six-point scale (grade 0-5). A sum score ≥19 indicates clinically relevant psychological distress. A Likert scale was used to assess overall experiences and impact on sports and lifestyle. RESULTS: A total of 275 participants (86.5% response rate, 95% CI 83-90%) with a mean age of 54.5 ± 6.4 years completed the questionnaires, 48 (17.5%, 95% CI 13-22%) of whom had CAD. The median IES score was 1 (IQR 0-2, [0-23]). IES was slightly higher in those with CAD (mean rank 175 vs. 130, p < 0.001). One participant (with CAD) experienced clinically relevant psychological distress (IES = 23). Participants reported numerous benefits, including feeling safer exercising (58.6%, 95% CI 53-65%) and positive lifestyle changes, especially in those with CAD (17.2 vs. 52.1%, p < 0.001). The majority were satisfied with their participation (93.8%, 95% CI 91-97%). CONCLUSION: Cardiovascular PPS, including cardiac CT, causes no relevant psychological distress in older sportsmen. Psychological distress should not be a reason to forego screening in sportsmen.

Effects of a pre-operative home-based inspiratory muscle training programme on perceived health-related quality of life in patients undergoing coronary artery bypass graft surgery.

OBJECTIVES: Pre-operative inspiratory muscle training has been shown to decrease the incidence of postoperative pneumonia and length of hospital stay in patients undergoing coronary artery bypass graft surgery (CABG). This study investigated if this decrease acted as a mediator on the time course of quality of life. DESIGN: Complementary analyses of a published randomised controlled trial. SETTING AND PARTICIPANTS: The initial trial included patients awaiting CABG surgery at a Dutch university hospital. The secondary analyses used data from the initial trial for patients who had completed at least one quality-of-life questionnaire. METHODS: Participants were allocated at random to the intervention group or the usual care group. The intervention group followed a home-based pre-operative inspiratory muscle training programme. Quality of life was measured at five time points. Between-group differences in quality-of-life scores were analysed using mixed linear modelling. RESULTS: The secondary analyses used data for 235 patients. In line with the initial trial, pneumonia and length of hospital stay were decreased significantly in the intervention group. The time courses for all patients showed significant improvements in quality of life after surgery compared with baseline. No significant differences in quality of life were observed over time between the two groups. CONCLUSION: Despite decreased incidence of pneumonia and length of hospital stay in the intervention group, this study did not find any improvements in quality of life due to the pre-operative home-based inspiratory muscle training programme. Clinical trial registration number ISRCTN17691887.

Sports injuries and illnesses during the European Youth Olympic Festival 2013.

BACKGROUND: The European Youth Olympic Festival (EYOF) is a biennial sporting event of nine Olympic Summer Sports for talented athletes, aged 13-18 years, from all over Europe. OBJECTIVE: To analyse the injuries and illnesses that occurred during the multisport event (14-19 July 2013), with the long-term aim of enabling international sports federations, the National Olympic Committees, and the European Olympic Committee to improve protection of athletes' health in youth. METHODS: Daily occurrence or non-occurrence of injuries and illnesses was recorded by using the IOC injury and illness surveillance system for multisport events. All National Olympic Committee physicians and healthcare providers and physicians of the Local Organizing Committee were invited to participate. RESULTS: In total, 2272 athletes from 49 countries took part in the EYOF 2013. During the five competition days of EYOF, 207 injuries and 46 illnesses were reported, resulting in an incidence of 91.1 injuries and 20.2 illnesses per 1000 athletes. Almost 10% of the athletes sustained at least one injury or illness. CONCLUSIONS: This study is the first multisport surveillance study on injuries and illnesses during the EYOF or any other summer Games organised for youth elite athletes. The data form the basis for further research on risk factors and injury mechanisms for this cohort. This research is needed to gain more knowledge and finally to implement effective injury and illness prevention measures.

Rationale and design of the Measuring Athlete's Risk of Cardiovascular events (MARC) study : The role of coronary CT in the cardiovascular evaluation of middle-aged sportsmen.

BACKGROUND: More than 90 % of exercise-related cardiac arrests occur in men, predominantly those aged 45 years and older with coronary artery disease (CAD) as the main cause. The current sports medical evaluation (SME) of middle-aged recreational athletes consists of a medical history, physical examination, and resting and exercise electrocardiography. Coronary CT (CCT) provides a minimally invasive low radiation dose opportunity to image the coronary arteries. We present the study protocol of the Measuring Athlete's Risk of Cardiovascular events (MARC) study. MARC aims to assess the additional value of CCT to a routine SME in asymptomatic sportsmen ≥45 years without known CAD. DESIGN: MARC is a prospective study of 300 asymptomatic sportsmen ≥45 years who will undergo CCT if the SME does not reveal any cardiac abnormalities. The prevalence and determinants of CAD (coronary artery calcium score ≥100 Agatston Units (AU) or ≥50 % luminal stenosis) will be reported. The number needed to screen to prevent the occurrence of one cardiovascular event in the next 5 years, conditional to adequate treatment, will be estimated. DISCUSSION: We aim to determine the prevalence and severity of CAD and the additional value of CCT in asymptomatic middle-aged (≥45 years) sportsmen whose routine SME revealed no cardiac abnormalities.

Ankle injuries in the Netherlands: Trends over 10-25 years.

Ankle injuries are a common health problem; data on ankle injury rates and time trends in the population at large are scarce. Our aim was to investigate the incidence of and time trends in population-based and emergency department-treated ankle injuries related to sports activities and other activities related to daily living. Data were obtained from one national survey on accidents and injuries (2000-2010) and one based on emergency department data (1986-2010). Linear regression was used to determine linear trends in ankle injuries per 1000 person-years. The number of ankle injuries related to sports activities and other activities of daily living increased from 19.0 to 26.6 per 1000 person-years (P = 0.002). The number of sports-related ankle injuries treated in emergency departments decreased from 4.2 to 1.5 per 1000 person-years (P < 0.001), and from 3.2 to 2.1 per 1000 person-years (P < 0.001) for other activities of daily living. According to our data, the incidence rates of all ankle injuries are around 5.5 times higher than those registered at emergency departments. The high incidence rates of ankle injuries highlight the need for proper ankle injury treatment and prevention.

Differences in injury risk and characteristics between Dutch amateur and professional soccer players.

OBJECTIVES: To compare the incidence and characteristics of injuries between Dutch amateur and professional male soccer players during one entire competition season. DESIGN: A prospective two-cohort design. METHODS: During the 2009-2010 season, 456 Dutch male amateur soccer players and 217 professional players were prospectively followed. Information on injuries and individual exposure to all soccer activities were recorded in both cohorts. Injuries were recorded using the time-loss definition. RESULTS: In total, 424 injuries were recorded among 274 of the amateur players (60.1% injured players) and 286 injuries were sustained by 136 (62.7% injured players) of the professional players (p=0.52). Compared to the professionals, the injury incidence during training sessions was higher among amateurs (p=0.01), but the injury incidence among professionals was higher during matches (p<0.001). Professional players also had a higher incidence of minimal injuries (p<0.001), whereas the incidence of moderate and severe injuries was higher for amateurs (all p<0.001). Lastly, professional players sustained more overuse injuries (p=0.02), whereas amateurs reported more recurrent injuries (p<0.001). CONCLUSIONS: The above-mentioned differences in injury rates between amateur and professional players in the Netherlands might be explained by the difference in the level at which they play, since factors like the availability of medical support and/or the team size may influence the injury risk and characteristics.

A prospective study on MRI findings and prognostic factors in athletes with MTSS.

In medial tibial stress syndrome (MTSS) bone marrow and periosteal edema of the tibia on the magnetic resonance imaging (MRI) is frequently reported. The relationship between these MRI findings and recovery has not been previously studied. This prospective study describes MRI findings of 52 athletes with MTSS. Baseline characteristics were recorded and recovery was related to these parameters and MRI findings to examine for prognostic factors. Results showed that 43.5% of the symptomatic legs showed bone marrow or periosteal edema. Absence of periosteal and bone marrow edema on MRI was associated with longer recovery (P = 0.033 and P = 0.013). A clinical scoring system for sports activity (SARS score) was significantly higher in the presence of bone marrow edema (P = 0.027). When clinical scoring systems (SARS score and the Lower Extremity Functional Scale) were combined in a model, time to recovery could be predicted substantially (explaining 54% of variance, P = 0.006). In conclusion, in athletes with MTSS, bone marrow or periosteal edema is seen on MRI in 43,5% of the symptomatic legs. Furthermore, periosteal and bone marrow edema on MRI and clinical scoring systems are prognostic factors. Future studies should focus on MRI findings in symptomatic MTSS and compare these with a matched control group.

Risk factors for hamstring injuries in male soccer players: a systematic review of prospective studies.

Hamstring injuries are common injuries in soccer players. In view of the high incidence and the serious consequences, identifying risk factors related to hamstring injuries is essential. The aim of this systematic review was therefore to identify risk factors for hamstring injuries in male adult soccer players. PubMed, Embase/Medline, Cumulative Index to Nursing and Allied Health Literature, and SPORTDiscus were systematically searched, and prospective studies investigating risk factors for hamstring injuries in adult male soccer players were included. The methodological quality of the included articles was assessed using a standardized set of predefined criteria. Seven of the 11 studies identified, involving a total of 1775 players and 344 hamstring injuries, met the inclusion criteria. All but one of the included studies met at least five of nine methodological criteria, causing them to be qualified as 'high quality'. The included studies used univariate as well as multivariate analyses to identify risk factors for hamstring injury. The results from the multivariate analyses suggest that previous hamstring injury is most strongly related to hamstring injury. Conflicting evidence is found for age and hamstring length or flexibility as risk factors for the occurrence of hamstring injuries.

Bone mineral density and vitamin D status in Parkinson's disease patients.

Bone loss is more common in Parkinson's disease (PD) than in the general population. Several factors may be involved in the development of bone loss, including malnutrition, immobilization, low body mass index, decreased muscle strength, vitamin D deficiency and medication use. This study investigates the prevalence of osteoporosis and possible risk factors associated with bone loss in early stage PD. In 186 PD patients (Hoehn and Yahr stage 1-2.5, mean age 64.1 years, 71 % men) bone mineral density (BMD) measurements were performed with DEXA. T- and Z-scores were calculated. Univariate linear regression analysis was performed to identify variables that contributed to BMD. 25-OH-vitamin D status of PD patients was compared with 802 controls (mean age 63.3 years, 50 % men) using linear regression analysis. Osteoporosis (11.8 %) and osteopenia (41.4 %) were common in PD patients. Mean Z-score for the hip was 0.24 (SD 0.93), and for the lumbar spine 0.72 (SD 1.91). Female gender, low weight, and low 25-OH-vitamin D were significantly correlated with BMD of the hip and lumbar spine. PD patients had lower 25(OH)D serum levels than controls (B = -10, p = 0.000). More than half of the patients with early stage PD had an abnormal BMD. Female gender, low weight, and low vitamin D concentration were associated with bone loss. Furthermore, vitamin D concentrations were reduced in PD patients. These results underscore the importance of proactive screening for bone loss and vitamin D deficiency, even in early stages of PD.