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Purpose: While several studies have documented isokinetic knee strength in junior and senior rugby league players, investigations of isokinetic knee and hip strength in professional rugby union players are limited. The purpose of this study was to provide lower-extremity strength profiles and compare isokinetic knee and hip strength of professional rugby league and rugby union players. Participants: 32 professional rugby league and 25 professional rugby union players. Methods: Cross-sectional analysis. Isokinetic dynamometry was used to evaluate peak torque and strength ratios of the dominant and nondominant legs during seated knee-extension/ flexion and supine hip-extension/flexion actions at 60°/s. Results: Forwards from both codes were taller and heavier and had a higher body-mass index than the backs of each code. Rugby union forwards produced significantly (P < .05) greater peak torque during knee flexion in the dominant and nondominant legs (ES = 1.81 and 2.02) compared with rugby league forwards. Rugby league backs produced significantly greater hip-extension peak torque in the dominant and nondominant legs (ES = 0.83 and 0.77) compared with rugby union backs. There were no significant differences in hamstring-to-quadriceps ratios between code, position, or leg. Rugby union forwards and backs produced significantly greater knee-flexion-to-hip-extension ratios in the dominant and nondominant legs (ES = 1.49-2.26) than rugby union players. Conclusions: It seems that the joint torque profiles of players from rugby league and union codes differ, which may be attributed to the different demands of each code. [ABSTRACT FROM AUTHOR]

The purpose of this study was to quantify the inter-session reliability of force–velocity–power profiling and estimated maximal strength in youth. Thirty-six males (11–15 years old) performed a ballistic supine leg press test at five randomized loads (80%, 100%, 120%, 140%, and 160% body mass) on three separate occasions. Peak and mean force, power, velocity, and peak displacement were collected with a linear position transducer attached to the weight stack. Mean values at each load were used to calculate different regression lines and estimate maximal strength, force, velocity, and power. All variables were found reliable (change in the mean [CIM] = − 1 to 14%; coefficient of variation [CV] = 3–18%; intraclass correlation coefficient [ICC] = 0.74–0.99), but were likely to benefit from a familiarization, apart from the unreliable maximal force/velocity ratio (CIM = 0–3%; CV = 23–25%; ICC = 0.35–0.54) and load at maximal power (CIM = − 1 to 2%; CV = 10–13%; ICC = 0.26–0.61). Isoinertial force–velocity–power profiling and maximal strength in youth can be assessed after a familiarization session. Such profiling may provide valuable insight into neuromuscular capabilities during growth and maturation and may be used to monitor specific training adaptations. [ABSTRACT FROM PUBLISHER]

The aim of the study was to validate the self-report Multimedia Activity Recall for Children and Adolescents (MARCA) against accelerometry for the assessment of physical activity in New Zealand children. Participants (n = 716, 10–18 years) recalled 3–4 days of activity using the MARCA and underwent a partially overlapping 7-day accelerometry protocol during a national survey. Spearman correlation coefficients (ρ) assessed the association between accelerometer-derived counts per minute and MARCA-derived physical activity level and time in locomotion. Both data sources estimated time spent in light and moderate–vigorous physical activity. Association and agreement between methods for light physical activity and moderate–vigorous physical activity was assessed using correlations and Bland–Altman plots respectively, and pairedt-tests conducted. Accelerometer-derived activity counts were moderately correlated with both MARCA-derived physical activity level and locomotion (ρ = 0.38,P < 0.0001). The correlation between methods was –0.14 for light physical activity and 0.28 for moderate–vigorous physical activity (P < 0.0001). The MARCA overestimated moderate–vigorous physical activity compared with accelerometry (120 min,P < 0.0001), which increased as moderate–vigorous physical activity time increased. Some sex and ethnicity (Māori [indigenous] versus non-Māori) differences were observed. Overall, the MARCA indicated moderate validity for assessment of physical activity level, locomotion and moderate–vigorous physical activity and poor validity for assessment of light physical activity. This was comparable to other self-report tools. The MARCA has utility for future large-scale research. [ABSTRACT FROM PUBLISHER]

Research measuring whole-body protein turnover (WBPT) after both exercise and nutrition has generally focused on resistance exercise; however, there is a paucity of data regarding the effect of postaerobic exercise nutrition, especially in older adults. It is not known if postexercise protein feeding has a beneficial effect on protein turnover after low- to moderate-intensity exercise. We investigated whether consuming protein plus carbohydrate (PRO) immediately after an acute bout of aerobic exercise has an additive effect over carbohydrate alone (CHO) on WBPT in older individuals. Twelve healthy older adults (age, 59 ± 4 years) were studied on 2 separate occasions after 1 h of exercise at approximately 50% of maximal rate of oxygen uptake, followed by 4 h of recovery. Immediately following exercise, subjects ingested a CHO (60 g) or an isocaloric PRO beverage (40 g carbohydrate, 20 g whey protein). Whole-body protein metabolism was determined using [1-13C]leucine infusion (60 mg prime; 75 mg·h-1 continuous), and sampling blood and expired breath. Rates of whole-body leucine appearance and oxidation, and nonoxidative leucine disposal during the third and fourth hours of postexercise recovery were higher in the PRO group (2.51 ± 0.55, 0.78 ± 0.37, and 1.71 ± 0.44 µmol·kg-1·min-1, respectively) than in the CHO group (1.81 ± 0.27, 0.33 ± 0.14, and 1.47 ± 0.25 µmol·kg-1·min-1, respectively; p = 0.001). Our results indicate that consumption of a PRO beverage after aerobic exercise increased WBPT to a greater extent than a CHO beverage. Les études s'intéressant à la mesure du renouvellement global des protéines dans l'organisme (WBPT) à la suite d'un exercice physique et d'un apport alimentaire traitent généralement du rôle des exercices de force; néanmoins, il y a peu d'études sur les effets d'un apport alimentaire à la suite d'un exercice aérobie particulièrement chez les personnes âgées. On ne sait pas si un apport protéique après un exercice suscite un effet bénéfique sur le renouvellement protéique consécutif à un exercice d'intensité légère à modérée. Cette étude se propose de vérifier si, comparativement à un apport de sucres seulement (CHO), un apport protéique combiné à des sucres (PRO) immédiatement après un bref effort aérobie apporte des effets additionnels concernant le WBPT chez des personnes âgées. On invite en deux occasions douze adultes en bonne santé et âgés de 59 ± 4 ans à participer à une séance d'exercice d'une durée de 60 min et d'intensité suscitant 50 % du consommation d'oxygene maximale suivie d'une récupération d'une durée de 4 h. Immédiatement après la fin de l'exercice, les sujets consomment soit une boisson contenant des sucres (CHO; 60 g) soit une boisson contenant des sucres et des protéines (PRO; 40 g de sucres et 20 g de protéines lactosériques) totalisant la même quantité d'énergie. On évalue le métabolisme protéique de l'organisme en entier par l'administration de [1-13C] leucine (infusion immédiate de 60 mg suivie d'une perfusion à raison de 75 mg·h-1) et l'analyse des échantillons de sang et des gaz expirés. Les taux corporels d'apparition de la leucine, de son oxydation et de l'élimination de la fraction non oxydée au cours de la 3e et de la 4e heure de la période de récupération postexercice sont plus importants dans la condition PRO (2,51 ± 0,55, 0,78 ± 0,37 et 1,71 ± 0,44 μmol·kg-1·min-1 respectivement) que dans la condition CHO (1,81 ± 0,27, 0,33 ± 0,14 et 1,47 ± 0,25 μmol·kg-1·min-1 respectivement) (p = 0,001). Nos observations révèlent qu'un apport de protéines à la suite d'un exercice aérobie suscite une plus grande augmentation du WBPT que ne le fait un apport de sucres. Un apport protéique à la suite d'un exercice semble favorable à l'amélioration de la qualité des protéines contenues dans l'organisme en entier et pourrait apporter des gains en matière de capacité physique chez les personnes âgées. [ABSTRACT FROM AUTHOR]