Rugby Players Exhibit Stiffer Biceps Femoris, Lower Biceps Femoris Fascicle Length to Knee Extensors, and Knee Flexors to Extensors Muscle Volume Ratios Than Active Controls.

PURPOSE: This study aimed to determine if hamstring-strain-injury risk factors related to muscle structure and morphology differed between rugby union players and controls. METHODS: The biceps femoris long head (BFlh) fascicle length and passive muscle stiffness and relative and absolute muscle volume of knee flexors (KF) and extensors (KE) were measured in 21 male subelite rugby players and 21 male physically active nonathletes. RESULTS: BFlh fascicle length was significantly longer (mean difference [MD] = 1.6 [1.7] cm) and BFlh passive muscle stiffness was significantly higher in rugby players (MD = 7.8 [14.8] kPa). The absolute BFlh (MD = 71.9 [73.3] cm3), KF (MD = 332.3 [337.2] cm3), and KE (MD = 956.3 [557.4] cm3) muscle volumes were also significantly higher in rugby players. There were no significant differences in the relative BFlh and KF muscle volumes. The relative KE muscle volumes were significantly higher in rugby players (MD = 2.3 [3.7] cm3/kg). However, the percentage BFlh fascicle length:KE (MD = -0.1% [0.1%]), BFlh/KE (MD = -0.9% [1.9%]), and KF:KE (MD = -4.9% [5.9%]) muscle volume ratios were significantly lower in the rugby players. BFlh muscle volume significantly correlated with BFlh fascicle length (r = .59, r2 = .35) and passive muscle stiffness (r = .46, r2 = .21). CONCLUSION: Future prospective studies should examine whether there are threshold values in BFlh passive muscle stiffness and BFlh fascicle length:KE, BFlh:KE, and KF:KE muscle volume ratios for predicting hamstring strain injuries.

Noncontact Injury Distribution and Relationship With Preseason Training Load and Nonmodifiable Risk Factors in Rugby Union Players Across Multiple Seasons.

ABSTRACT: Evans, SL, Whittaker, G, Elphinstone Davis, E, Jones, ES, Hardy, J, and Owen, JA. Noncontact injury distribution and relationship with preseason training load and non-modifiable risk factors in Rugby Union players across multiple seasons. J Strength Cond Res 37(7): 1456-1462, 2023-This study examined the distribution of noncontact injury during phases of the competitive season and the association between preseason training load (TL) and nonmodifiable risk factors on injury risk during these phases. Injury data were recorded from 1 senior academy team over 3 seasons (2017-2020) and analyzed across early-season, midseason, and late-season phases. A generalized estimating equation was used to model risk factors with noncontact injury for selected phases. The highest noncontact injury incidence occurred in the late-season phase (22.2 per 1,000 hours) compared with early (13.7 per 1,000 hours, p < 0.001) and midseason phases (15.5 per 1,000 hours, p = 0.001). Low preseason TL (8,949-12,589 arbitrary units; odds ratio [OR], 95% confidence interval [CI] = 4.7, 1.0-21.6; p = 0.04) and low preseason TL combined with high early-season TL and injury in the early-season phase (OR, 95% CI = 6.5, 1.1-35.5; p = 0.03) were associated with greater midseason noncontact injury risk. In addition, low preseason TL combined with previous injury was associated with increased risk of noncontact injury risk in the late season (OR, 95% CI = 12.2, 0.9-15.6, p = 0.05). Our results suggest players are at a greater injury risk during the late-season phase, with low preseason cumulative loads combined with a history of previous injury associated with increased in-season injury risk. Strength and conditioning coaches should therefore monitor cumulative preseason TL alongside screening for previous injury history to identify athletes at greater risk of noncontact injury risk during the competitive season.

Pre-competitive anxiety and autonomic responses in professional U-20 futsal players: Effect of the competition phase and game location.

The study examined whether pre-competition anxiety and autonomic responses in elite futsal players change across the playoffs at away vs home venues. Heart rate variability, somatic and cognitive anxiety and self-confidence (by CSAI-2R questionnaire) were evaluated in nine male futsal players from a professional U-20 team, before competitive matches at the quarter-final, semi-final and final stages played at home and away venues. Two-way ANOVA for repeated measures was used, considering factor one the game location and factor two the playoff stage, with significance set at p<0.05. Significant effects of the playoff stage were demonstrated in the Mean of HR (F = 4.643; p = 0.014) and SD2 index (F = 14.83; p=<0.001)(quarter versus final). No difference was found for somatic and cognitive anxiety and self-confidence between the two factors. The results suggest that play at the final stage of the playoff, regardless of the game location, may cause higher physiological stress, demonstrated by elevated HR and decrease of SD2 index.

Match and training injury risk in semi-professional rugby union: A four-year study.

OBJECTIVES: Describe medical-attention and time-loss injuries during matches and training in a Welsh Premiership Rugby Union team. DESIGN: Prospective cohort observational study. METHODS: Injury incidence, severity, burden, location, type, and cause were determined in sixty-nine players from one semi-professional Rugby Union team. RESULTS: Medical-attention and time-loss injury incidence was greater for matches (incidence, 95% confidence interval = 122.8, 108.9-138.4 and 99.8, 87.3-114.0) than training (incidence, 95% confidence interval = 2.2, 1.8-2.6 and 1.7, 1.4-2.1) per 1000 player-hours. Injury severity was similar for matches (time-loss ± standard deviation = 24.9 ± 30.8 days) and training (time-loss ± SD = 22.4 ± 29.1 days), with injury burden greater for matches (burden, 95% confidence interval = 3148.8, 3019.8-6479.2) than training (burden, 95% confidence interval = 49.7, 36.7-129.6). Lower-limb time-loss injuries were most common during matches (incidence, 95% confidence interval = 46.0, 37.9-55.9) and training (incidence, 95% confidence interval = 1.3, 1.0-1.7) per 1000 player-hours, whilst upper-limb injuries were most severe in matches (time-loss, 95% confidence interval = 38.8, 28.3-44.4 days) and training (time-loss, 95% confidence interval = 45.9, 17.5-52.7 days). The prevalent cause of contact-injury was tackling (31%) with running (11%) the common cause of non-contact injury. CONCLUSIONS: Time-loss match-injury incidence, severity, and burden were similar to data reported in the professional tier, with similar patterns of injuries for location, type, and inciting event. These figures are greater than previously reported for semi-professional Rugby Union, warranting further investigation at this level of play.

An exploratory study to investigate the association between age, physical activity, femoral trochlear cartilage thickness and biomarkers of tissue metabolism in adult males.

PURPOSE: To investigate the association between age, physical activity, femoral trochlear cartilage thickness and biomarkers of tissue metabolism in a cross-sectional sample of adult males. This study utilizes several emerging biomarkers that have been associated with early joint degenerative changes; serum COMP (cartilage oligomeric matrix protein), HA (hyaluronan) and lubricin. METHODS: Eighty-one males (age: mean (range): 43(18-70) years; body mass index: 25.2 (21.0-30.6) kg/m2) volunteered. Resting serum COMP, HA and lubricin concentrations were determined via commercially available enzyme-linked immunosorbent assay (ELISA) and femoral trochlear cartilage thickness via supra-patellar ultrasound imaging. Physical activity levels were assessed using questionnaires. Statistical analyses were performed using correlation and regression analyses. RESULTS: Age was correlated with lateral trochlear cartilage thickness (r = - 0.372; p < 0.01) and serum COMP (r = 0.342; p < 0.01). 7-day physical activity was correlated with serum COMP (r = 0.357, p < 0.01), and 12-month physical activity with both lateral trochlear cartilage thickness (r = 0.340, p = 0.01) and serum HA (r = 0.296, p < 0.05). Regression analyses revealed that age significantly accounted for the variability in lateral cartilage thickness and serum COMP, following the adjustment for potential cofounders. However, the association between age and lateral trochlear cartilage thickness was not moderated by physical activity levels (all p > 0.05). CONCLUSION: This study indicates that older age may be associated with thinner lateral trochlear cartilage and higher cartilage turnover. Being physically active may also be positive for lateral trochlear cartilage thickness. However, overall, both age and physical activity level only account for a small amount of the variability in cartilage thickness and serum biomarkers.

The impact of menstrual-cycle phase on basal and exercise-induced hormones, mood, anxiety and exercise performance in physically active women.

BACKGROUND: The influence of menstrual cycle phase on perceptual responses and exercise performance is still unclear in the literature. Therefore, this study investigated salivary estradiol (sal-E2) and cortisol (sal-C) concentrations, mood, anxiety and exercise (aerobic, anaerobic) performance in physically-active women across two menstrual-cycle phases. METHODS: Twelve women (mean age 24.9±4.3 years) were assessed in the early follicular (early-FP) and mid luteal (mid-LP) phase of their menstrual cycle. In each phase, participants were tested for both aerobic (i.e. VO2max) and anaerobic (i.e. peak power, average power and Fatigue Index) performance. Basal and exercise-induced changes in sal-E2 and sal-C concentrations, self-appraised mood and anxiety were assessed. RESULTS: We observed a significant increase in basal (pre-exercise) sal-E2 concentration from early-FP to mid-LP (P≤0.05), coupled with a significant increase in VO2max in early-FP (39.9±7.8 mL/kg/min) versus mid-LP (36.9±7.8 mL/kg/min). Depression also decreased with aerobic exercise, but only in the early-FP. No other significant menstrual-phase differences in exercise performance, emotional state or hormonal change scores were identified. CONCLUSIONS: Our data suggest that physically-active women may experience a natural rise in estradiol concentration, as they transition from the early-FP to mid-LP. In the present study, this was accompanied by a small reduction in VO2max. An exercise (aerobic)-related decline in depression also emerged in the early-FP. Most of the exercise performance, emotional state and hormonal measures did not exhibit any menstrual phase-related difference.

Hydration Marker Diagnostic Accuracy to Identify Mild Intracellular and Extracellular Dehydration.

Identifying mild dehydration (≤2% of body mass) is important to prevent the negative effects of more severe dehydration on human health and performance. It is unknown whether a single hydration marker can identify both mild intracellular dehydration (ID) and extracellular dehydration (ED) with adequate diagnostic accuracy (≥0.7 receiver-operating characteristic-area under the curve [ROC-AUC]). Thus, in 15 young healthy men, the authors determined the diagnostic accuracy of 15 hydration markers after three randomized 48-hr trials; euhydration (water 36 ml·kg-1·day-1), ID caused by exercise and 48 hr of fluid restriction (water 2 ml·kg-1·day-1), and ED caused by a 4-hr diuretic-induced diuresis begun at 44 hr (Furosemide 0.65 mg/kg). Body mass was maintained on euhydration, and dehydration was mild on ID and ED (1.9% [0.5%] and 2.0% [0.3%] of body mass, respectively). Urine color, urine specific gravity, plasma osmolality, saliva flow rate, saliva osmolality, heart rate variability, and dry mouth identified ID (ROC-AUC; range 0.70-0.99), and postural heart rate change identified ED (ROC-AUC 0.82). Thirst 0-9 scale (ROC-AUC 0.97 and 0.78 for ID and ED) and urine osmolality (ROC-AUC 0.99 and 0.81 for ID and ED) identified both dehydration types. However, only the thirst 0-9 scale had a common dehydration threshold (≥4; sensitivity and specificity of 100%; 87% and 71%, 87% for ID and ED). In conclusion, using a common dehydration threshold ≥4, the thirst 0-9 scale identified mild intracellular and ED with adequate diagnostic accuracy. In young healthy adults', thirst 0-9 scale is a valid and practical dehydration screening tool.

Validity and Reliability of a Non-invasive Test to Assess Quadriceps and Hamstrings Strength in Athletes.

Modifiable risk factors for hamstring injury include lack of strength, fatigue and muscle strength asymmetry. Assessing lower body strength in the field is problematic as "gold standard assessment" are expensive, non-portable and assessment is time-consuming. Therefore, the objective of this study was to examine the validity and reliability of an adapted aneroid sphygmomanometer test of hamstring and quadricep strength. In 14 active males (age 23.1 ± 2.5 years; height 180.9 ± 8.2 cm; weight 88.4 ± 8.5 kg). concurrent validity was assessed by comparing the adapted sphygmomanometer assessment at 30 and 90° of knee flexion to isokinetic dynamometry using Pearson product-moment correlation. The reliability of the adapted sphygmomanometer was assessed in 10 professional rugby players (age 21.5 ± 2.6 years; height 177.2 ± 5.8 cm; weight 92.7 ± 5.8 kg ) across two visits. Sphygmomanometer strength assessments of hamstring and quadriceps were associated with isokinetic measures (Quadricep: right, r = 0.386, 95% CI = 0.136-0.866, p < 0.05; left, r = 0.431, 95% CI = 0.193-0.880, p < 0.05), hamstring strength at 90° of knee flexion (Hamstring: right, r = 0.545, 95% CI = 0.342-0.912, p < 0.01; left, r = 0.643, 95% CI = 0.473-0.935, p < 0.001) and hamstring strength at 30° of knee flexion (right, r = 0.329, 95% CI = 0.062-0.846, p < 0.05; left, r = 0.387, 95% CI = 0.138-0.867, p < 0.05). However, the adapted test was not able to identify bilateral or hamstring to quadricep asymmetry. Test-retest reliability was high for most assessments (ICC range: 0.64-0.92), and SEM measures ranged between 5 and 12%, with the smallest change representing a change in strength ranging between 3 and 4%. In conclusion, an adapted sphygmomanometer test for hamstring and quadricep strength assessment was valid and reliable in assessing hamstring and quadricep strength but not bilateral or hamstring and quadricep asymmetry.

Is this elderly patient dehydrated? Diagnostic accuracy of hydration assessment using physical signs, urine, and saliva markers.

OBJECTIVES: Dehydration in older adults contributes to increased morbidity and mortality during hospitalization. As such, early diagnosis of dehydration may improve patient outcome and reduce the burden on healthcare. This prospective study investigated the diagnostic accuracy of routinely used physical signs, and noninvasive markers of hydration in urine and saliva. DESIGN: Prospective diagnostic accuracy study. SETTING: Hospital acute medical care unit and emergency department. PARTICIPANTS: One hundred thirty older adults [59 males, 71 females, mean (standard deviation) age = 78 (9) years]. MEASUREMENTS: Participants with any primary diagnosis underwent a hydration assessment within 30 minutes of admittance to hospital. Hydration assessment comprised 7 physical signs of dehydration [tachycardia (>100 bpm), low systolic blood pressure (<100 mm Hg), dry mucous membrane, dry axilla, poor skin turgor, sunken eyes, and long capillary refill time (>2 seconds)], urine color, urine specific gravity, saliva flow rate, and saliva osmolality. Plasma osmolality and the blood urea nitrogen to creatinine ratio were assessed as reference standards of hydration with 21% of participants classified with water-loss dehydration (plasma osmolality >295 mOsm/kg), 19% classified with water-and-solute-loss dehydration (blood urea nitrogen to creatinine ratio >20), and 60% classified as euhydrated. RESULTS: All physical signs showed poor sensitivity (0%-44%) for detecting either form of dehydration, with only low systolic blood pressure demonstrating potential utility for aiding the diagnosis of water-and-solute-loss dehydration [diagnostic odds ratio (OR) = 14.7]. Neither urine color, urine specific gravity, nor saliva flow rate could discriminate hydration status (area under the receiver operating characteristic curve = 0.49-0.57, P > .05). In contrast, saliva osmolality demonstrated moderate diagnostic accuracy (area under the receiver operating characteristic curve = 0.76, P < .001) to distinguish both dehydration types (70% sensitivity, 68% specificity, OR = 5.0 (95% confidence interval 1.7-15.1) for water-loss dehydration, and 78% sensitivity, 72% specificity, OR = 8.9 (95% confidence interval 2.5-30.7) for water-and-solute-loss dehydration). CONCLUSIONS: With the exception of low systolic blood pressure, which could aid in the specific diagnosis of water-and-solute-loss dehydration, physical signs and urine markers show little utility to determine if an elderly patient is dehydrated. Saliva osmolality demonstrated superior diagnostic accuracy compared with physical signs and urine markers, and may have utility for the assessment of both water-loss and water-and-solute-loss dehydration in older individuals. It is particularly noteworthy that saliva osmolality was able to detect water-and-solute-loss dehydration, for which a measurement of plasma osmolality would have no diagnostic utility.