Handgrip strength asymmetry as a new biomarker for sarcopenia and individual sarcopenia signatures.

BACKGROUND: Although handgrip strength (HGS) asymmetry has clinical screening utility, its relevance to sarcopenia is unknown. This study examined the relationship between HGS asymmetry and sarcopenia signatures, and explored the relevance of circulating neural/neuromuscular markers. METHODS: 9403 individuals aged 18-92 years participated in this study. Maximal HGS and skeletal muscle index (SMI) were determined using hand dynamometry and DXA. Sarcopenia was diagnosed upon the presence of low HGS and low SMI, according to cohort-specific thresholds. Plasma biomarkers were measured by ELISA in a sub-group of 269 participants aged 50-83 years. Asymmetry was determined as the highest recorded HGS divided by the highest recorded HGS of the opposite hand. Individuals with a ratio > 1.10 were classified as having asymmetrical HGS. RESULTS: Subjects with asymmetrical HGS had significantly lower SMI (7.67 kg/m2 vs 7.71 kg/m2, p = 0.004) and lower HGS (37.82 kg vs 38.91 kg, p < 0.001) than those with symmetrical HGS. In those aged ≥ 50 years asymmetrical HGS was associated with 2.67 higher odds for sarcopenia [95% confidence interval: (CI) = 1.557-4.561, p < 0.001], 1.83 higher odds for low HGS only (CI 1.427-2.342, p < 0.001), and 1.79 higher odds for low SMI only (CI 1.257-2.554, p = 0.001). HGS asymmetry demonstrated acceptable diagnostic accuracy for sarcopenia (AUC = 0.727, CI 0.658-0.796, p < 0.001). Plasma neural cell adhesion molecule concentrations were 19.6% higher in individuals with asymmetrical HGS (185.40 ng/mL vs 155.00 ng/mL, p < 0.001) than those with symmetrical HGS. DISCUSSION: Our findings demonstrate the utility of HGS asymmetry as a screening tool that may complement existing strategies seeking to combat sarcopenia. Biomarker analyses suggest that heightened denervation may be an important aetiological factor underpinning HGS asymmetry.

Contact injuries in field hockey and the potential role for personal protective equipment.

Field hockey is played with sticks and a hard ball. It is fast-paced, with athletes playing together in close proximity. Athletes may be at increased risk of sustaining injuries through contact. The aim of this study was to investigate the epidemiological characteristics of contact injuries in field hockey. Data were collected during the 2017/2018 and 2018/2019 Irish Hockey League seasons. This study included two methods of data collection among male athletes: self-reported injuries and via those reported by the teams' physiotherapists. Injuries were defined as any physical complaint sustained during field hockey, supplemented by medical attention and time-loss injuries. Only contact injuries were included for analysis. Overall, 107 contact injuries were incurred, giving rise to an injury incidence rate of 3.1/1000 h, and accounting for 33.1% of all injuries. Athletes had an absolute risk of 0.372 of sustaining a contact injury. Contusions (48.6%) were the most common type of contact injury, while injuries to the head/face (20.6%) were the most frequently reported location. Contact injuries represent an important proportion of all injuries. Rule changes to mandate the use of personal protective equipment in field hockey may assist in reducing the absolute risk and severity of contact injuries in field hockey.

Longitudinal Association Between Participation in Organized Sport and Psychosocial Development in Early Childhood.

OBJECTIVE: To explore whether the associations between developmental delays in the first year of life and psychosocial outcomes in preschool children are affected by participation in organized sport. STUDY DESIGN: Data were obtained from the infant cohort of the Growing Up in Ireland project. Parents reported on child development (Ages and Stages Questionnaire) at age 1 year, psychosocial characteristics (Strengths and Difficulties Questionnaire) at ages 3 and 5 years, and engagement in organized sport at age 5 years. Data were analyzed using mixed models. RESULTS: At age 1 year, 15% of the cohort was classified as having developmental delays. These children exhibited more behavioral difficulties (0.55, ±0.27; mean difference, ±95% confidence limits [CL]) (P < .0001) and fewer prosocial behaviors (-0.54, ±0.11) (P < .0001) at age 3 years. For boys in this group, engagement in sport was associated with a significant decrease in behavioral difficulties between ages 3 and 5 years (-0.44, ±0.39) (P = .03). Compared with those classified as lacking regular engagement (ie, never engaging, or engaging <1 hour/week), the relative effect of sport on changes in behavioral difficulties for boys with developmental delays was statistically significant (0.70, ±0.59) (P = .02). Participation in sport was not associated with significant changes in behavioral difficulties for girls, or a significant change in prosocial behaviors for boys or girls. CONCLUSIONS: Regular participation in sport by boys could attenuate some of the behavioral difficulties associated with early development. Lack of opportunities for engaging in sport could negatively affect boys' behavioral regulation in the preschool period.

The burden of injury in field hockey: A secondary analysis of prospective cohort data.

Most studies report injuries based upon their incidence rate, or the number of injuries which occur in a sport per unit of time. While this is recommended across numerous consensus statements on reporting injury data in sport, it may be of benefit to consider injury burden also. Reporting injuries as the duration of injury per 1000 exposure hours highlights those injuries which will likely cause greater disruption within a team. Therefore, the primary aim of this study was to report the burden of injury in field hockey. This secondary analysis of epidemiological data employed two methods of data collection: self-reported through an online reporting software, and through contact with the team physiotherapist. Athletes reported injury-related symptoms for 4170 days in total, giving rise to an injury burden of 121.0/1000 h, of which 61.4/1000 h were days lost through injury. Injuries to the hamstring, as well as muscle strain injuries, caused the most significant injury burden in athletes (22.6 and 35.8/1000 h respectively). Reporting injuries as the duration of injuries per 1000 hours highlights those injuries which cause the most significant disruption within a squad. Future injury prevention strategies in field hockey should prioritize the injuries which are most burdensome.

Reliability of walking speed in basic and complex conditions in healthy, older community-dwelling individuals.

BACKGROUND: There is a paucity of reliability data for walking speed tests in complex conditions to assess functioning in healthy older individuals. AIMS: To evaluate the absolute intra- and intertest reliability of walking speed performed in basic and complex conditions in healthy older individuals. METHODS: Fifty-two men and women of mean age 69.7 ± 3.2 years were tested for habitual and maximal walking speed. Maximal speed was also assessed under different conditions, including walking on a path of reduced width; picking up objects; stepping over hurdles; stepping over hurdles wearing sunglasses and finally, carrying a box. Two testing sessions (separated by 4 weeks) of two trials each were administered. Reliability was analysed by intra-class correlation coefficient (ICC), minimal detectable change (MDC) and Bland-Altman plots with limits of agreement (LOA). RESULTS: Intrasession ICCs ranged from good to excellent (0.89-0.95) except for picking up objects (0.44). Intersession ICCs were moderate to good (0.60-0.78) and %MDCs were acceptable (14-24%). Bland-Altman plots suggested a good agreement between the two testing sessions at group level (mean differences from - 0.02 to - 0.11 m/s), and limited agreement between testing sessions at individual level (upper LOA from 0.13 to 0.37 m/s and lower LOA from - 0.29 to - 0.49 m/s). CONCLUSIONS: Complex walking speed tests are generally reliable measures displaying good and moderate intra- and inter-session reliability. Such tests seem a more suitable functional assessment tool for heathy older subjects compared with simple walking. Some learning effect may be present and further reliability studies are needed.

Mechanisms of acute ankle syndesmosis ligament injuries in professional male rugby union players: a systematic visual video analysis.

BACKGROUND: The mechanisms of acute ankle syndesmosis ligament injuries in professional rugby union are not well understood. AIM: To describe the mechanisms of acute ankle syndesmosis ligament injuries in male professional rugby union players using systematic visual video analysis. METHODS: All time-loss acute ankle syndesmosis ligament injuries identified via retrospective analysis of the Leinster Rugby injury surveillance database across the 2013/2014 to 2017/2018 seasons were considered as potentially eligible for inclusion. Three Chartered Physiotherapists (analysts) independently assessed all videos with a final consensus meeting convened to describe the injury mechanisms. One of the analysts developed a qualitative description of each injury mechanism. RESULTS: Thirteen acute ankle syndesmosis injuries were included in this study. The most common biomechanical presentation of the injured limb was characterised by hip flexion, knee flexion, knee valgus, ankle dorsiflexion, pronation and external rotation of the foot. Six of the included injuries (46%) were the result of an external load application to the injured limb (ie, direct contact injuries). In the other seven instances (54%), the injury was the result of a collapse of the injured player's body mass over the injured ankle joint, while tackling or being tackled, without direct contact to the injured limb (ie, indirect contact injuries). CONCLUSION: Injuries incurred while tackling were exclusively the result of suboptimal tackle mechanics. A majority of injuries incurred while being tackled involved a posterior tackle, which often resulted in a posterior collapse of the injured player's centre of mass over a fixed externally rotated foot.

Epidemiology of injuries in senior men's field hockey: A two-season prospective observational injury surveillance study.

Determining the rate and severity of injuries incurred through sport is accepted as the primary step towards designing, implementing and evaluating injury prevention programmes. The aim of this study was to determine the injury incidence rate and characteristics of male field hockey athletes participating in the Irish Hockey League. Athletes from eight field hockey teams were assigned to an online reporting system, where they logged injuries as they were incurred. Injuries were defined as any physical complaint. Coaches and physiotherapists were contacted weekly to corroborateinjuries. Overall 323 injuries were reported across 34,449 exposure hours, giving rise to an incidence rate of 9.4/1000 h. On average, athletes sustained one injury over the course of two seasons. Muscle strains, pain and contusions were the most common types of injury, while the hamstring, knee and hip/groin were the most frequently reported locations. While 66.9% of injuries occurred through non-contact mechanisms, contact injuries were also common. Injury recurrences accounted for 16.1% of injuries. In conclusion, the incidence of injury in field hockey is high, occurring from a variety of mechanisms. Future injury prevention strategies should prioritise injuries to the hamstring, knee and ankle, and be specific to particular playing positions.

Sex differences in sagittal plane control emerge during adolescent growth: a prospective investigation.

PURPOSE: Females athletes have a higher incidence of non-contact knee joint injuries compared to their male counterparts. This may be attributable to sex-specific differences in neuromuscular control, which arise during the pubertal growth spurt. The purpose of this longitudinal study was to assess the development of landing kinematics of adolescent male and female athletes during the adolescent growth-spurt. METHODS: One hundred and eighty-four adolescent athletes (55% male, 45% female; mean age = 13 ± 0.3 years) participated. Testing was undertaken at baseline and then repeated at 6, 12, 18 and 24 months. Participants performed three drop vertical jump (DVJ) trials from a 31 cm box. Frontal and sagittal plane knee joint angles were recorded. The average measurement of the three jumps was used for analysis at each time point. To assess maturation status, participants were categorised according to their age from peak height velocity at baseline. Pre-initial contact knee flexion (pre-IC), peak knee flexion and knee valgus displacement were the dependant variables. The categorical independent variables were sex (male versus female) and time. RESULTS: There was a significant sex*time interaction for pre-IC knee flexion, with males increasing knee flexion with time to a greater extent than females. There was no significant sex*time interaction for knee valgus displacement; although females displayed greater knee valgus displacement across all time points. CONCLUSIONS: Adolescent male and female athletes display differing kinematic profiles across growth and development. This has clinical relevance for emphasising increased knee flexion, as well as decreasing abnormal frontal plane displacement in injury prevention programmes for adolescent females. LEVEL OF EVIDENCE: II.

Dietary patterns and cardiovascular risk factors in adolescents and young adults: the Northern Ireland Young Hearts Project.

Dietary pattern (DP) analysis allows examination of the combined effects of nutrients and foods on the markers of CVD. Very few studies have examined these relationships during adolescence or young adulthood. Traditional CVD risk biomarkers were analysed in 12-15-year-olds (n 487; Young Hearts (YH)1) and again in the same individuals at 20-25 years of age (n 487; YH3). Based on 7 d diet histories, in the present study, DP analysis was performed using a posteriori principal component analysis for the YH3 cohort and the a priori Mediterranean Diet Score (MDS) was calculated for both YH1 and YH3 cohorts. In the a posteriori DP analysis, YH3 participants adhering most closely to the 'healthy' DP were found to have lower pulse wave velocity (PWV) and homocysteine concentrations, the 'sweet tooth' DP were found to have increased LDL concentrations, and decreased HDL concentrations, [corrected] the 'drinker/social' DP were found to have lower LDL and homocysteine concentrations, but exhibited a trend towards a higher TAG concentration, and finally the 'Western' DP were found to have elevated homocysteine and HDL concentrations. In the a priori dietary score analysis, YH3 participants adhering most closely to the Mediterranean diet were found to exhibit a trend towards a lower PWV. MDS did not track between YH1 and YH3, and nor was there a longitudinal relationship between the change in the MDS and the change in CVD risk biomarkers. In conclusion, cross-sectional analysis revealed that some associations between DP and CVD risk biomarkers were already evident in the young adult population, namely the association between the healthy DP (and the MDS) and PWV; however, no longitudinal associations were observed between these relatively short time periods.

Neuromechanics of repeated stepping with external loading in young and older women.

PURPOSE: An understanding of the neuromechanical responses to bench stepping with external loading is important for exercise prescription, especially in older women who are more at risk than men for disability. This study was designed to describe and compare such responses to repeated bench stepping with external loading between young and older women. METHODS: Eight young (25 ± 2.7 years) and nine older (70 ± 3.3 years) medically stable women performed repeated stepping on a bench of either 20 or 25 cm either unloaded or with 2.5, 5, 7.5 or 10 % of body mass (BM) incorporated into a weighted vest. Ground reaction forces, peak power output and agonist-antagonist neuromuscular activation around the knee joint were evaluated. RESULTS: Peak power output was 44 % lower in the older than in the younger women. At a step height of 25 cm, peak power (PP) in the young women was 7 % greater with an external load of 7.5 % body mass compared with no loading, while in the older women there was a tendency for PP to be higher with an external load of 2.5 % body mass. Neuromuscular activation of the vastus lateralis muscle was 60 % higher in the older than in the young women. CONCLUSIONS: Older women performed repeated weighted-vest stepping with lower power output but greater knee muscle activation compared to younger counterparts. Peak power output during stepping may be achieved at 7.5 % BM loading in young women and either 2.5 or 10 % BM in older women, depending on desired step height.

The effects of aerobic exercise training at two different intensities in obesity and type 2 diabetes: implications for oxidative stress, low-grade inflammation and nitric oxide production.

AIMS: To investigate the effect of 16 weeks of aerobic training performed at two different intensities on nitric oxide (tNOx) availability and iNOS/nNOS expression, oxidative stress (OS) and inflammation in obese humans with or without type 2 diabetes mellitus (T2DM). METHODS: Twenty-five sedentary, obese (BMI > 30 kg/m2) males (52.8 ± 7.2 years); 12 controls versus 13 T2DM were randomly allocated to four groups that exercised for 30 min, three times per week either at low (Fat-Max; 30-40% VO(2max)) or moderate (T(vent); 55-65 % VO(2max)) intensity. Before and after training, blood and muscle samples (v. lateralis) were collected. RESULTS: Baseline erythrocyte glutathione was lower (21.8 ± 2.8 vs. 32.7 ± 4.4 nmol/ml) and plasma protein oxidative damage and IL-6 were higher in T2DM (141.7 ± 52.1 vs. 75.5 ± 41.6 nmol/ml). Plasma catalase increased in T2DM after T(vent) training (from 0.98 ± 0.22 to 1.96 ± 0.3 nmol/min/ml). T2DM groups demonstrated evidence of oxidative damage in response to training (elevated protein carbonyls). Baseline serum tNOx were higher in controls than T2DM (18.68 ± 2.78 vs. 12.34 ± 3.56 µmol/l). Training at T(vent) increased muscle nNOS and tNOx in the control group only. Pre-training muscle nNOS was higher in controls than in T2DMs, while the opposite was found for iNOS. No differences were found after training for plasma inflammatory markers. CONCLUSION: Exercise training did not change body composition or aerobic fitness, but improved OS markers, especially when performed at T(vent). Non-diabetics responded to T(vent) training by increasing muscle nNOS expression and tNOx levels in skeletal muscle while these parameters did not change in T2DM, perhaps due to higher insulin resistance (unchanged after intervention).

Measures of static postural control moderate the association of strength and power with functional dynamic balance.

BACKGROUND AND AIMS: Age-related reductions in strength and power are considered to negatively impact balance control, but the existence of a direct association is still an issue of debate. This is possibly due to the fact that balance assessment is complex, reflects different underlying physiologic mechanisms and involves quantitative measurements of postural sway or timing of performance during balance tasks. The present study evaluated the moderator effect of static postural control on the association of power and strength with dynamic balance tasks. METHODS: Fifty-seven healthy 65-75 year old individuals performed tests of dynamic functional balance (walking speed under different conditions) and of strength, power and static postural control. RESULTS AND CONCLUSIONS: Dynamic balance performance (walking speed) was associated with lower limb strength and power, as well as postural control under conditions requiring postural adjustments (narrow surface walking r(2) = 0.31, p < 0.001). An interaction effect between strength and static postural control was found with narrow surface walking and talking while walking (change of ß 0.980, p < 0.001 in strength for 1 SD improvements in static postural control for narrow walking, and [Formula: see text] -0.730, p < 0.01 in talking while walking). These results indicate that good static postural control facilitates the utilisation of lower limb strength to better perform complex, dynamic functional balance tasks. Practical implications for assessment and training are discussed.

Dynamic postural stability in young adolescent male and female athletes.

PURPOSE: To investigate dynamic postural stability performance of young adolescent athletes. METHODS: Eighty-nine male and 81 female athletes participated. Each participant performed 3 trials of the anterior, posterior-medial, and posterior-lateral reach directions of the Star Excursion Balance Test on each limb. Distance achieved for each direction was expressed as a percentage of leg length, with the composite reach distance of these directions being used for statistical analysis. RESULTS: No significant interaction effect for sex and limb dominance (P > .05) was found, nor was a significant main effect for sex or limb dominance (P > .05) observed. Notably, the composite reach distance achieved by both male and female athletes was less than 94% of leg length, a value that has previously been identified for increased injury risk in adolescent athletes. CONCLUSION: Further longitudinal research is needed to fully understand how dynamic postural stability changes over adolescence.

Grip strength positively correlates with blood pressure in individuals with abnormal adiposity.

Although strong positive correlations exist between grip strength and cardiovascular health, the association between grip strength and blood pressure (BP) is less clear. In this regard, a more precise relationship between grip strength and BP may be revealed by considering adiposity. We examined the association between grip strength and BP in 9424 individuals aged 18-92 years, while controlling for or stratifying by body mass index (BMI) or body fat (BF)%. Grip strength, BP and BF% were determined using dynamometry, sphygmomanometry and dual-energy x-ray absorptiometry. Overall, those with elevated BP had greater grip strength than those with normal BP (39.17 kg vs 38.38 kg, p < 0.001); however, following stratification this was only observed in overweight or obese individuals (42.08 kg vs 41.10 kg, p = 0.003 and 41.34 kg vs 40.03 kg, p = 0.033), and those within the highest BF% tertile (37.95 kg vs 36.52 kg, p < 0.001). Overall, higher grip strength was associated with an increased odds for elevated BP (OR = 1.014, 95% CI = 1.004-1.024, p = 0.004); however, after stratification the increased odds was only observed in overweight or obese individuals (OR = 1.025, 95% CI = 1.010-1.039, p < 0.001 and OR = 1.018, 95% CI = 1.004-1.031, p = 0.010), and those within the highest BF% tertile (OR = 1.036, 95% CI = 1.022-1.051, p < 0.001). Individuals with low grip strength and high BF% had lower odds for elevated BP (OR = 0.514, 95% CI = 0.341-0.775, p = 0.002), whereas those with low grip strength and low BF% had higher odds for elevated BP (OR = 2.162, 95% CI = 1.026-4.555, p = 0.043). Our findings show that higher grip strength is related to higher BP in overweight or obese individuals, or those with a high BF%. Having a BMI < 25 kg/m2 or lower BF% may neutralise this association.

Plasma C-terminal agrin fragment concentrations across adulthood: Reference values and associations with skeletal muscle health.

BACKGROUND: Increasing interest surrounds the utility of blood-based biomarkers for diagnosing sarcopenia. C-terminal agrin fragment (CAF), a marker of neuromuscular junction stability, is amongst the most promising candidates; however, a dearth of reference data impedes the incorporation of its use in public health settings. This study aimed to establish reference values for plasma CAF concentrations across adulthood in a large, well-characterized cohort of healthy adults; and comprehensively examine the association between plasma CAF levels and skeletal muscle health. METHODS: One thousand people aged between 18 and 87 years took part in this study (mean age = 50.4 years; 51% females). Body composition and muscle strength were examined using DXA and hand dynamometry. Plasma CAF concentrations were measured, in duplicate, using commercially available ELISA kits. Sarcopenia and individual sarcopenia signatures [low skeletal muscle index (SMI) only/low grip strength only] were classified using the EWGSOP2 algorithm. RESULTS: Detailed reference CAF values, according to sex and age, are presented. A significant but modest age-related increase in plasma CAF concentration was observed (P = 0.018). Across adulthood, CAF concentrations were negatively associated with grip strength and SMI (both P < 0.001). In people ≥50 years old, CAF concentrations were 22.6% higher in those with sarcopenia (P < 0.001), 11.3% higher in those with low SMI (P = 0.006) and 9.6% higher in those with low grip strength (P = 0.0034), compared with controls. People in the highest CAF concentration quartile, had 3.25 greater odds for sarcopenia (95% CI = 1.41-7.49, P = 0.005), 2.76 greater odds for low SMI (95% CI = 1.24-5.22, P = 0.012), and 2.56 greater odds for low grip strength (95% CI = 1.07-5.57, P = 0.037), compared with those in the lowest quartile. People with a CAF Z-score ≥2 had 9.52 greater odds for sarcopenia (95% CI = 3.01-30.05, P < 0.001) compared with a Z-score <1. Plasma CAF concentration had an acceptable level of diagnostic accuracy for sarcopenia (AUC = 0.772, 95% CI = 0.733-0.807, P < 0.001). CONCLUSIONS: The reference values presented herein may guide the clinical interpretation of circulating CAF and help identify people at risk of poor skeletal muscle outcomes for inclusion in therapeutic interventions. Our findings add clarity to existing data, demonstrating a robust relationship between circulating CAF and skeletal muscle integrity in the largest adult cohort to date, and support the use of CAF as an accessible, cost-effective screening tool for sarcopenia. However, further research into the prognostic utility of plasma CAF, and the establishment of normative data from other populations, are urgently needed if routine CAF screening is to be embedded into public healthcare settings.

High-density lipoprotein subfractions display proatherogenic properties in overweight and obese children.

BACKGROUND: In adults, obesity-driven inflammation can lead to increased cardiovascular disease (CVD). However, information regarding childhood obesity and its inflammatory sequelae is less well defined. Serum amyloid-A (SAA) is an inflammatory molecule that rapidly associates with high-density lipoproteins (HDLs) and renders them dysfunctional. Therefore, SAA may be a useful biomarker to identify increased CVD potential in overweight and obese children. METHODS: Young Hearts 2000 is a cross-sectional cohort study in which 92 children who were obese were matched for age and sex with 92 overweight and 92 lean children. HDL(2) and HDL(3) (HDL(2&3)) were isolated from plasma by a three-step rapid-ultracentrifugation procedure. SAA was measured in serum and HDL(2&3) by an enzyme-linked immunosorbent assay procedure, and the activities of cholesterol ester transfer protein (CETP) and lecithin cholesteryl acyltransferase (LCAT) were measured by fluorimetric assays. RESULTS: Trends across the groups indicated that SAA increased in serum and HDL(2&3) as BMI increased, as did HDL(2)-CETP and HDL(2)-LCAT activities. CONCLUSION: These results have provided evidence that overweight and obese children are exposed to an inflammatory milieu that impacts the antiatherogenic properties of HDL and that could increase CVD risk. This supports the concept that it is important to target childhood obesity to help minimize future cardiovascular events.