Mental health and vitality predict spinal pain in healthcare workers.

BACKGROUND: Despite extensive investigation of ergonomic risk factors for spinal pain in healthcare workers, limited knowledge of psychological risk factors exists. AIMS: To assess the prospective association of mental health and vitality with development of spinal pain in healthcare workers. METHODS: A prospective cohort study was carried out involving 1950 healthcare workers from 19 hospitals in Denmark. Assessments were done at baseline and at 1-year follow-up. Mental health and vitality were measured using the Short Form-36 Health Survey, while spinal pain intensity was measured using a 0-10 scale in the low-back, upper-back and neck, respectively. Cumulative logistic regressions adjusted for several confounding factors were applied, reporting risk estimates as odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Using good mental health as reference, moderate (but not poor) mental health at baseline was associated with increased pain intensity in the low-back (OR: 1.41 [95% CI: 1.21-1.77]), upper-back (OR: 1.63 [95% CI: 1.31-2.02]) and neck (OR: 1.31 [95% CI: 1.07-1.61]) at 1-year follow-up. Likewise, using high vitality as reference, both moderate and low vitality at baseline were associated with increased pain intensity in the low-back (OR: 1.54 [95% CI: 1.22-1.94] and OR: 2.34 [95% CI: 1.75-3.12], respectively), upper-back (OR: 1.72 [95% CI: 1.34-2.23] and OR: 2.46 [95% CI: 1.86-3.25], respectively) and neck (OR: 1.66 [95% CI: 1.34-2.06] and OR: 2.06 [95% CI: 1.61-2.63], respectively) at 1-year follow-up. CONCLUSIONS: Compared to healthcare workers with good mental health and high vitality, those with moderate mental health and low/moderate vitality, respectively, were more likely to increase spinal pain intensity at 1-year follow-up. These components should also be considered in the prevention of spinal pain in healthcare workers.

The unexplored role of sedentary time and physical activity in glucose and lipid metabolism-related placental mRNAs in pregnant women who are obese: the DALI lifestyle randomised controlled trial.

OBJECTIVE: We aimed to explore: (i) the association of sedentary time (ST) and physical activity (PA) during pregnancy with the placental expression of genes related to glucose and lipid metabolism in pregnant women who are obese; (ii) maternal metabolic factors mediating changes in these placental transcripts; and (iii) cord blood markers related to the mRNAs mediating neonatal adiposity. DESIGN: Multicentre randomised controlled trial. SETTING: Hospitals in nine European countries. POPULATION: A cohort of 112 pregnant women with placental tissue. METHODS: Both ST and moderate-to-vigorous PA (MVPA) levels were measured objectively using accelerometry at three time periods during pregnancy. MAIN OUTCOME MEASURES: Placental mRNAs (FATP2, FATP3, FABP4, GLUT1 and PPAR-γ) were measured with NanoString technology. Maternal and fetal metabolic markers and neonatal adiposity were assessed. RESULTS: Longer periods of ST, especially in early to middle pregnancy, was associated with lower placental FATP2 and FATP3 expression (P < 0.05), whereas MVPA at baseline was inversely associated with GLUT1 mRNA (P = 0.02). Although placental FATP2 and FATP3 expression were regulated by the insulin-glucose axis (P < 0.05), no maternal metabolic marker mediated the association of ST/MVPA with placental mRNAs (P > 0.05). Additionally, placental FATP2 expression was inversely associated with cord blood triglycerides and free fatty acids (FFAs; P < 0.01). No cord blood marker mediated neonatal adiposity except for cord blood leptin, which mediated the effects of PPAR-γ on neonatal sum of skinfolds (P < 0.05). CONCLUSIONS: In early to middle pregnancy, ST is associated with the expression of placental genes linked to lipid transport. PA is hardly related to transporter mRNAs. Strategies aimed at reducing sedentary behaviour during pregnancy could modulate placental gene expression, which may help to prevent unfavourable fetal and maternal pregnancy outcomes. TWEETABLE ABSTRACT: Reducing sedentary behaviour in pregnancy might modulate placental expression of genes related to lipid metabolism in women who are obese.

First-time anterior cruciate ligament injury in adolescent female elite athletes: a prospective cohort study to identify modifiable risk factors.

PURPOSE: To identify modifiable biomechanical and neuromuscular anterior cruciate ligament (ACL) injury risk factors for first-time ACL injury in adolescent female elite football and team handball players. METHODS: Adolescent female elite football and handball players with no previous ACL injury participated in the present study. At baseline, players were tested during side-cutting manoeuvres performed in a 3-dimensional motion analysis laboratory with concomitant electromyography (EMG) measurements. Maximal isometric lower limb muscle strength was assessed by handheld dynamometry. Players were prospectively followed for 2 years after baseline testing, and all magnetic resonance imaging (MRI) verified ACL injuries were registered. The effect of 16 risk factor candidates on the relative risk (RR) of ACL injury was estimated using Poisson regression analysis. RESULTS: Ninety players (age 16.9 ± 1.2 years) were included in the analyses. Nine first-time ACL injuries (injury incidence 10.0% (95% confidence interval (CI) 5.4-18.6%)) were registered during the 2-year follow-up period. Four risk factor candidates were significantly associated with the risk of ACL injury: (1) hip flexion angle at initial contact (IC) [RR 0.56, 95% confidence interval (CI) 0.34-0.92], (2) internal knee rotation angle at IC [RR 1.13, 95% CI 1.08-1.19], (3) semitendinosus EMG activity 50 ms prior to IC [RR: 0.62, 95% CI 0.43-0.89], and (4) external hip rotator strength [RR: 0.77, 95% CI 0.66-0.89]. CONCLUSION: Four distinct ACL injury risk factors related to the side-cutting manoeuvre were identified in a population of adolescent female elite football and team handball players with no previous ACL injury. As ACL injury typically occur during side-cutting, intervention programmes to modify these risk factors pose a promising strategy for ACL injury prevention in adolescent female elite football and team handball. LEVEL OF EVIDENCE: II.

Metabolic phenotypes of early gestational diabetes mellitus and their association with adverse pregnancy outcomes.

AIMS: To describe the metabolic phenotypes of early gestational diabetes mellitus and their association with adverse pregnancy outcomes. METHODS: We performed a post hoc analysis using data from the Vitamin D And Lifestyle Intervention for gestational diabetes prevention (DALI) trial conducted across nine European countries (2012-2014). In women with a BMI ≥29 kg/m2 , insulin resistance and secretion were estimated from the oral glucose tolerance test values performed before 20 weeks, using homeostatic model assessment of insulin resistance and Stumvoll first-phase indices, respectively. Women with early gestational diabetes, defined by the International Association of Diabetes and Pregnancy Study Groups criteria, were classified into three groups: GDM-R (above-median insulin resistance alone), GDM-S (below-median insulin secretion alone), and GDM-B (combination of both) and the few remaining women were excluded. RESULTS: Compared with women in the normal glucose tolerance group (n = 651), women in the GDM-R group (n = 143) had higher fasting and post-load glucose values and insulin levels, with a greater risk of having large-for-gestational age babies [adjusted odds ratio 3.30 (95% CI 1.50-7.50)] and caesarean section [adjusted odds ratio 2.30 (95% CI 1.20-4.40)]. Women in the GDM-S (n = 37) and GDM-B (n = 56) groups had comparable pregnancy outcomes with those in the normal glucose tolerance group. CONCLUSIONS: In overweight and obese women with early gestational diabetes, higher degree of insulin resistance alone was more likely to be associated with adverse pregnancy outcomes than lower insulin secretion alone or a combination of both.

Influence of physical and psychosocial working conditions for the risk of disability pension among healthy female eldercare workers: Prospective cohort.

Aim: To investigate the influence of physical and psychosocial working conditions on the risk of disability pension among eldercare workers. Methods: After responding to a questionnaire in 2005, 4699 healthy female eldercare workers - free from chronic musculoskeletal pain, depressive symptoms and long-term sickness absence - were followed for 11 years in the Danish Register for Evaluation of Marginalization. Time-to-event analyses estimated the hazard ratio (HR) for disability pension from physical exertion during work, emotional demands, influence at work, role conflicts, and quality of leadership. Analyses were mutually adjusted for these work environmental factors as well as for age, education, smoking, leisure physical activity and body mass index. Results: During follow-up, 7.6% received disability pension. Physical exertion and emotional demands were associated with risk of disability pension, and both interacted with age. In age-stratified analyses, older eldercare workers (mean age 53 years at baseline) with moderate and high physical exertion (reference: low) were at increased risk with HRs of 1.51, 95% CI [1.06-2.15] and 2.54, 95% CI [1.34-4.83], respectively. Younger eldercare workers (mean age 36 years at baseline) with moderate emotional demands (reference: low) were at decreased risk with an HR of 0.57, 95% CI [0.37-0.85]. Conclusions: While a higher level of physical exertion is a risk factor for disability pension among older female eldercare workers, a moderate level of emotional demands is associated with lower risk among the younger workers. The age of the worker may be an important factor when providing recommendations for promoting a long and healthy working life.

Association between physical activity and sickness absenteeism in university workers.

BACKGROUND: Sedentary occupations have increased by more than 10% in Western countries over the last two decades, and the yearly global cost of physical inactivity has been estimated to be $53.8 billion. As workers tend to move less in the workplace, they are more likely to develop a sedentarism-related chronic condition and to be absent from work due to illness, although research evidence on the issue remains unclear. AIMS: To investigate associations between physical activity (PA) and sickness absenteeism in the workplace among Spanish university workers. METHODS: We conducted cross-sectional research with data from 1025 workers aged 18-65 years (43% women) from a Spanish university. Physical Activity Vital Sign (PAVS) and International Physical Activity Questionnaire (IPAQ) short versions were used to evaluate levels of PA. Workplace absenteeism was self-reported by participants. Written questionnaires distributed during medical checks included PAVS, IPAQ and the question about absenteeism among other information. The association between PA and sickness absenteeism was examined using adjusted multiple linear regression. RESULTS: After adjusting for age, sex, job function, chronic conditions, sedentarism and smoking, each weekly hour of PA reduced sickness absence by -1.20 (95% confidence interval: -2.40-0.00) days per year. CONCLUSIONS: The implementation of PA promotion strategies aimed at university employees may lead to a reduction of days off work due to illness.

Hamstring-to-quadriceps fatigue ratio offers new and different muscle function information than the conventional non-fatigued ratio.

Commonly used injury risk prediction tests such as the hamstring-to-quadriceps (H:Q) strength ratio appear to be poor predictors of non-contact injury. However, these tests are typically performed in a non-fatigued state, despite accumulated fatigue being an important risk factor for both hamstring strain (HS) and anterior cruciate ligament (ACL) injuries in professional soccer players. After the effect of different H:Q calculation methods were compared and contrasted, the influence of neuromuscular fatigue on the H:Q strength ratio and the association between fatigued and non-fatigued ratio scores were examined. Thirty-five professional soccer players performed a 30-repetition isokinetic fatigue test protocol. Peak knee joint moments were computed for each repetition, and the H:Q conventional ratio (H:QCR ) was calculated using several different, previously published, methods. Knee extensor and flexor moments were statistically decreased by the sixth repetition and continued to decrease until the end of the protocol. However, the H:Q ratio was statistically decreased at the end of the test due to a significant reduction in knee flexor moment (correlation between change in knee flexor moment and change in H:Q, r≈.80; P<.01). Moreover, H:Q measured in fatigue (ie, H:QFatigue ) at the end of the test was greater than H:QCR (1.25-1.38 vs 0.70, P<.01), these variables were weakly correlated (r=.39, P=.02), and subject rankings within the cohort based on H:QCR and H:QFatigue were different (rs =0.25, P=.15). The present data suggest that H:Q ratio measurement during a fatiguing test (H:QFatigue ) provides different outcomes to the traditional H:QCR . The observed significant hamstring fatigue and the difference, and weak correlation, between H:QCR and H:QFatigue indicate that useful information might be obtained with respect to the prediction of HS and ACL injury risk. The potential predictive value of H:QFatigue warrants validation in future prospective trials.

Validity and reliability of elastic resistance bands for measuring shoulder muscle strength.

Valid and reliable measurements of muscle strength are important in sport medicine. This study assesses concurrent validity and intrarater reliability (test-retest reliability) of elastic resistance bands for measuring shoulder muscle strength. Altogether, 50 healthy adults [mean age 36.0 (SD: 11.6), 29 women and 21 men] participated in testing and retesting 1-2 weeks later. The maximal elastic resistance (TheraBand) that each participant could hold for 3 s during standing bilateral shoulder abduction to 90° was converted into torque and validated against gold standard maximal voluntary isometric contraction (MVC) (Vishay force transducer) performed unilaterally while lying supine. The intrarater reliability of both tests were high; for the MVC and elastic band test, respectively, ICC(3,1) was 0.98 (95% CI: 0.97-0.99) and 0.99 (95% CI: 0.98-1.00), and measurement error was 4.8% (95% CI: 3.7-5.9) and 4.7% (95% CI: 3.1-6.2). For concurrent validity, ICC(3,1) was 0.96 (95% CI: 0.95-0.98) and measurement error was 8.1% (95% CI: 6.6-9.6), and the elastic band test explained 93% of the variance in the MVC test. However, the elastic band test produced systematically lower torque values than the MVC [56.5 (SD: 26.8) vs 66.5 (SD: 25.5) Nm, P < 0.01]. In conclusion, the test for shoulder muscle strength using elastic resistance bands has excellent validity and reliability, but produces systematically lower torque values than MVC. The reason for the lower torque values may be that the elastic band test has an initial concentric phase and is performed bilaterally and standing upright.

Factors affecting pain relief in response to physical exercise interventions among healthcare workers.

The aim of this study is to identify factors associated with musculo-skeletal pain reduction during workplace-based or home-based physical exercise interventions among healthcare workers. Two hundred female healthcare workers (age: 42.0, BMI: 24.1, average pain intensity: 3.1 on a scale of 0-10) from three hospitals participated. Participants were randomly allocated at the cluster level (18 departments) to 10 weeks of (i) workplace physical exercise (WORK) performed in groups during working hours for 5 × 10 minutes per week and up to five group-based coaching sessions on motivation for regular physical exercise, or (ii) home-based physical exercise (HOME) performed alone during leisure-time for 5 × 10 minutes per week. Linear mixed models accounting for cluster identified factors affecting pain reduction. On average 2.2 (SD: 1.1) and 1.0 (SD: 1.2) training sessions were performed per week in WORK and HOME, respectively. The multi-adjusted analysis showed a significant effect on pain reduction of both training adherence (P=.04) and intervention group (P=.04) with participants in WORK experiencing greater reductions compared with HOME. Obesity at baseline was associated with better outcome. Leisure-time exercise, daily patient transfer, age, and chronic pain did not affect the changes in pain. In conclusion, even when adjusted for training adherence, performing physical exercise at the workplace is more effective than home-based exercise in reducing musculo-skeletal pain in healthcare workers. Noteworthy, obese individuals may especially benefit from physical exercise interventions targeting musculo-skeletal pain.

Efficacy of recreational football on bone health, body composition, and physical functioning in men with prostate cancer undergoing androgen deprivation therapy: 32-week follow-up of the FC prostate randomised controlled trial.

UNLABELLED: Androgen deprivation therapy (ADT) for prostate cancer (PCa) impairs musculoskeletal health. We evaluated the efficacy of 32-week football training on bone mineral density (BMD) and physical functioning in men undergoing ADT for PCa. Football training improved the femoral shaft and total hip BMD and physical functioning parameters compared to control. INTRODUCTION: ADT is a mainstay in PCa management. Side effects include decreased bone and muscle strength and increased fracture rates. The purpose of the present study was to evaluate the effects of 32 weeks of football training on BMD, bone turnover markers (BTMs), body composition, and physical functioning in men with PCa undergoing ADT. METHODS: Men receiving ADT >6 months (n = 57) were randomly allocated to a football training group (FTG) (n = 29) practising 2-3 times per week for 45-60 min or to a standard care control group (CON) (n = 28) for 32 weeks. Outcomes were total hip, femoral shaft, femoral neck and lumbar spine (L2-L4) BMD and systemic BTMs (procollagen type 1 amino-terminal propeptide, osteocalcin, C-terminal telopeptide of type 1 collagen). Additionally, physical functioning (postural balance, jump height, repeated chair rise, stair climbing) was evaluated. RESULTS: Thirty-two-week follow-up measures were obtained for FTG (n = 21) and for CON (n = 20), respectively. Analysis of mean changes from baseline to 32 weeks showed significant differences between FTG and CON in right (0.015 g/cm(2)) and left (0.017 g/cm(2)) total hip and in right (0.018 g/cm(2)) and left (0.024 g/cm(2)) femoral shaft BMD, jump height (1.7 cm) and stair climbing (-0.21 s) all in favour of FTG (p < 0.05). No other significant between-group differences were observed. CONCLUSIONS: Compared to standard care, 32 weeks of football training improved BMD at clinically important femoral sites and parameters of physical functioning in men undergoing ADT for PCa.

Self-reported previous knee injury and low knee function increase knee injury risk in adolescent female football.

Knee injuries are common in adolescent female football. Self-reported previous knee injury and low Knee injury and Osteoarthritis Outcome Score (KOOS) are proposed to predict future knee injuries, but evidence regarding this in adolescent female football is scarce. The aim of this study was to investigate self-reported previous knee injury and low KOOS subscale score as risk factors for future knee injuries in adolescent female football. A sample of 326 adolescent female football players, aged 15-18, without knee injury at baseline, were included. Data on self-reported previous knee injury and KOOS questionnaires were collected at baseline. Time-loss knee injuries and football exposures were reported weekly by answers to standardized text-message questions, followed by injury telephone interviews. A priori, self-reported previous knee injury and low KOOS subscale scores (< 80 points) were chosen as independent variables in the risk factor analyses. The study showed that self-reported previous knee injury significantly increased the risk of time-loss knee injury [relative risk (RR): 3.65, 95% confidence (CI) 1.73-7.68; P < 0.001]. Risk of time-loss knee injury was also significantly increased in players with low KOOS subscale scores (< 80 points) in Activities of Daily Living (RR: 5.0), Sport/Recreational (RR: 2.2) and Quality of Life (RR: 3.0) (P < 0.05). In conclusion, self-reported previous knee injury and low scores in three KOOS subscales significantly increase the risk of future time-loss knee injury in adolescent female football.

Five-year follow up of a randomised controlled trial comparing subtotal with total abdominal hysterectomy.

OBJECTIVES: To compare the rates of urinary incontinence (UI) and other complications of subtotal abdominal hysterectomy (SAH) with total abdominal hysterectomy (TAH) at 5 years after surgery. DESIGN: Randomised clinical trial with central, computer-generated randomisation. SETTING: Danish multi-centre trial performed in 11 departments of gynaecology. POPULATION: Women referred with benign uterine diseases scheduled for abdominal hysterectomy. METHODS: Women were randomised to either SAH (n = 161) or TAH (n = 158). Follow-up data were collected from participants using postal questionnaires sent out 5 years after surgery. Complications of hysterectomy were further examined by scrutinising registered discharge summaries following hospitalisation. Intention-to-treat and per-protocol analyses were conducted. Potential bias caused by missing data was handled using multiple imputation. MAIN OUTCOME MEASURES: The primary outcome was UI. Secondary outcomes included constipation, prolapse of the vaginal vault or cervical stump, satisfaction with sexual life, pelvic pain, postoperative complications and vaginal bleeding. RESULTS: The response rate was 234/319 (73.4%). A significantly higher proportion of respondents had urinary incontinence 5 years after SAH 34/113 (30.1%) than TAH 21/119 (17.6%) (RR 1.71, 95% confidence interval 1.06-2.75, P = 0.026). This difference reduced after multiple imputation to account for missing data (RR 1.37, 95% confidence interval 0.99-1.89, P = 0.052). Eleven of the 101 women (11%) in the SAH group still experienced vaginal bleeding. No other differences were found between the two types of abdominal hysterectomy. AUTHORS' CONCLUSIONS: A smaller proportion of women suffered from UI after TAH than after SAH 5 years postoperatively. Around one in ten women continued to experience vaginal bleeding 5 years after SAH.

Socio-economic status and incident diabetes mellitus among employees in Denmark: a prospective analysis with 10-year follow-up.

AIMS: To contribute to the research on diabetes and social inequality by presenting national data on incident diabetes mellitus, stratified according to socio-economic status. METHODS: National registers were combined, linking socio-economic status with incident diabetes over a 10-year period (2001-2010). The study population comprised employees in Denmark aged 20-59 years at baseline. Poisson regression analysis was used to estimate socio-economic rate ratios. Excess fraction analysis was used to determine the proportion of cases that would not have occurred if morbidity rates in each socio-economic group had been as low as those in the reference group. Monte Carlo simulation was used to calculate 95% CIs for excess fraction estimates RESULTS: A total of 1 005 572 men and 951 039 women were included in the analysis. The follow-up yielded 43 439 cases in 9 533 199 person-years at risk among men and 29 266 cases in 9 163 405 person-years at risk among women. Using 'professionals' as a reference group, higher levels of relative risk were observed among every other socio-occupational group. The excess fraction was, 0.342 (95% CI 0.329-0.354) among men and 0.359 (95% CI 0.349-0.369) among women. CONCLUSIONS: Excess fraction analysis suggests that more than a third of cases of diabetes could be prevented if all employees were exposed to the same working conditions as the reference population. Acknowledging potential confounders, the observed levels of incident diabetes among the workforce highlight the potential gains to be had by better use of the workplace as an arena for prevention. Greater integration of occupational health and general healthcare is required to achieve this.

Evaluation of elastic bands for lower extremity resistance training in adults with and without musculo-skeletal pain.

Therapists commonly use elastic bands in resistance exercises during rehabilitation of smaller muscles, such as in the shoulder. However, the effectiveness has not yet been investigated for larger muscle groups. This study investigates muscle activity during lower extremity exercises. Electromyographic (EMG) activity of 10 muscles was measured in 24 women and 18 men during lunges with elastic resistance, lunges with dumbbells, and unilateral leg press in machine using 10 repetition maximum loadings, and normalized to maximal voluntary isometric contraction EMG. Lunges with dumbbells and leg press showed higher activity than lunges with elastic resistance for the vasti and rectus femoris (P < 0.01), whereas lunges with elastic resistance showed higher activity of gluteus maximus, hamstrings, and erector spinae (P < 0.01). Gender, age, and pain in the knees and hip did not influence these findings. However, pain in the lower back decreased muscular activity of the gluteus maximus and vastus medialis (P < 0.01). Lunges with elastic resistance induce high levels of muscle activity in all the large muscle groups at the hip, knee, and back. Importantly, the efficiency of these exercises was equally high regardless of gender, age, and pain in the knees and hip, whereas pain in the lower back led to altered activation strategies.

Effect of football or strength training on functional ability and physical performance in untrained old men.

The effects of 16 weeks of football or strength training on performance and functional ability were investigated in 26 (68.2 ± 3.2 years) untrained men randomized into a football (FG; n = 9), a strength training (ST; n = 9), or a control group (CO; n = 8). FG and ST trained 1.6 ± 0.1 and 1.5 ± 0.1 times per week, respectively, with higher (P < 0.05) average heart rate (HR) (∼140 vs 100 bpm) and time >90%HRmax (17 vs 0%) in FG than ST, and lower (P < 0.05) peak blood lactate in FG than ST (7.2 ± 0.9 vs 10.5 ± 0.6 mmol/L). After the intervention period (IP), VO2 max (15%; P < 0.001), cycle time to exhaustion (7%; P < 0.05), and Yo-Yo Intermittent Endurance Level 1 performance (43%; P < 0.01) were improved in FG, but unchanged in ST and CO. HR during walking was 12% and 10% lower (P < 0.05) in FG and ST, respectively, after IP. After IP, HR and blood lactate during jogging were 7% (P < 0.05) and 30% lower (P < 0.001) in FG, but unchanged in ST and CO. Sit-to-stand performance was improved (P < 0.01) by 29% in FG and 26% in ST, but not in CO. In conclusion, football and strength training for old men improves functional ability and physiological response to submaximal exercise, while football additionally elevates maximal aerobic fitness and exhaustive exercise performance.

Does work-site physical activity improve self-reported psychosocial workplace factors and job satisfaction? A randomized controlled intervention study.

PURPOSE: To investigate whether a work-site strength-training program has a positive effect on self-reported psychosocial workplace factors and job satisfaction. METHODS: We conducted a randomized controlled trial among laboratory technicians implementing neck and shoulder exercises for pain relief, with 199 participants in the training group and 228 in the control group. Influence at work, sense of community, time pressure, and job satisfaction were measured with the Copenhagen Psychosocial Questionnaire at baseline and post-intervention after 20 weeks. RESULTS: There was no statistically significant change in any of the four variables in the training group from baseline to follow-up (all p ≥ 0.39). When we used MANOVA to test for between-group effects over time, we did not find any statistically significant result (all p > 0.14). CONCLUSIONS: This study does not provide evidence for an effect of a work-site strength-training program on self-reported psychosocial workplace factors and job satisfaction.

Handgrip strength and respiratory disease mortality: Longitudinal analyses from SHARE.

BACKGROUND: While the association between handgrip strength and all-cause mortality is more deeply explored, no previous studies have been specifically focused on handgrip strength and respiratory disease mortality. The purpose of the study was to investigate the association between handgrip strength and respiratory disease mortality in a large representative sample. METHODS: Individuals aged 50 or over from 27 European countries and Israel participated in this longitudinal study. Data on handgrip strength and all-cause and respiratory disease mortality were retrieved from the Survey of Health, Ageing and Retirement in Europe (SHARE) waves 1, 2, 4, 5, 6 and 7. We estimated the sub hazard ratios (SHRs) for respiratory disease mortality using a Fine-Gray sub-distribution method with both time-varying exposure and covariates and mortality due to other causes as competing risk. Furthermore, we assessed dose-response associations of handgrip strength (modelled as a continuous exposure) with respiratory disease mortality using restricted cubic splines and estimated hazard ratios (HRs). RESULTS: We included 60,883 men and 74,904 women with a mean age of 63.6 (SD 9.7) years at study entry. During a median (interquartile range) of 7.4 years of follow-up 565 (0.4%) participants died due to respiratory diseases. The increase of 1 single kg of handgrip strength showed a 6% incidence reduction on respiratory disease mortality (SHR, 0.94; 95%CI, 0.92-0.96) after adjusting for potential confounders. Furthermore, each kg increase of handgrip strength reduced respiratory disease mortality risk in a dose-response fashion and a significant threshold for values of 41 kg (HR, 0.49; 95%CI, 0.26-0.92) and higher was identified. CONCLUSIONS: Higher handgrip strength is associated with lower mortality due to respiratory disease. Intervention studies are needed to determine whether strength training in respiratory disease patients can prevent premature mortality.

Myostatin expression during human muscle hypertrophy and subsequent atrophy: increased myostatin with detraining.

Myostatin is a potent negative regulator of skeletal muscle mass, but its role in human skeletal muscle hypertrophy and atrophy is sparsely described. Muscle biopsies were obtained from young male subjects before and after 30 and 90 days of resistance training as well as after 3, 10, 30, 60 and 90 days of subsequent detraining. Myostatin mRNA increased significantly with detraining. We observed a 28 kDa myostatin immunoreactive protein, which, however, was also present in myostatin knock out mice skeletal muscle. As a novel finding we consistently detected a 10 kDa band, which may represent a mature myostatin monomer under reducing conditions or a novel, unknown myostatin form. Further, we observed a significant increase in this 10 kDa band after 3 days of detraining preceding the rapid type II fiber atrophy, in which almost half of the acquired fiber area was lost after only 10 days of detraining. Accordingly, an increase in the level of the 10 kDa protein is associated with rapid type II fiber atrophy, suggesting myostatin-mediated specific type II fiber atrophy, which in combination with our mRNA data support a role for myostatin in the negative regulation of adult human skeletal muscle mass.

Acute fatigue impairs neuromuscular activity of anterior cruciate ligament-agonist muscles in female team handball players.

In sports, like team handball, fatigue has been associated with an increased risk of anterior cruciate ligament (ACL) injury. While effects of fatigue on muscle function are commonly assessed during maximal isometric voluntary contraction (MVC), such measurements may not relate to the muscle function during match play. The purpose of this study was to investigate the effect of muscle fatigue induced by a simulated handball match on neuromuscular strategy during a functional sidecutting movement, associated with the incidence of ACL injury. Fourteen female team handball players were tested for neuromuscular activity [electromyography (EMG)] during a sidecutting maneuver on a force plate, pre and post a simulated handball match. MVC was obtained during maximal isometric quadriceps and hamstring contraction. The simulated handball match consisted of exercises mimicking handball match activity. Whereas the simulated handball match induced a decrease in MVC strength for both the quadriceps and hamstring muscles (P<0.05), a selective decrease in hamstring neuromuscular activity was seen during sidecutting (P<0.05). This study shows impaired ACL-agonist muscle (i.e. hamstring) activity during sidecutting in response to acute fatigue induced by handball match play. Thus, screening procedures should involve functional movements to reveal specific fatigue-induced deficits in ACL-agonist muscle activation during high-risk phases of match play.

Early and late rate of force development: differential adaptive responses to resistance training?

The objective of this study is to investigate the potentially opposing influence of qualitative and quantitative muscular adaptations in response to high-intensity resistance training on contractile rate of force development (RFD) in the early (<100 ms) and later phases (>200 ms) of rising muscle force. Fifteen healthy young males participated in a 14-week resistance training intervention for the lower body and 10 matched subjects participated as controls. Maximal muscle strength (MVC) and RFD were measured during maximal voluntary isometric contraction of the quadriceps femoris muscle. Muscle biopsies were obtained from the vastus lateralis. The main findings were that RFD in the late phase of rising muscle force increased in response to resistance training whereas early RFD remained unchanged and early relative RFD (i.e., RFD/MVC) decreased. Quantitatively, muscle fiber cross-sectional area and MVC increased whereas, qualitatively, the relative proportion of type IIX muscle fibers decreased. Multiple regression analysis showed that while increased MVC positively influenced both early and late RFD, decreased-type IIX negatively influenced early RFD only. In conclusion, early and late RFD responded differently to high-intensity resistance training due to differential influences of qualitative and quantitative muscular adaptations on early and later phases of rising muscle force.