It is unknown whether instantaneous visual feedback of resistance training outcomes can enhance barbell velocity in younger athletes. Therefore, the purpose of this study was to quantify the effects of visual feedback on mean concentric barbell velocity in the back squat, and to identify changes in motivation, competitiveness, and perceived workload. In a randomised-crossover design (Feedback vs. Control) feedback of mean concentric barbell velocity was or was not provided throughout a set of 10 repetitions in the barbell back squat. Magnitude-based inferences were used to assess changes between conditions, with almost certainly greater differences in mean concentric velocity between the Feedback (0.70 ±0.04 m·s) and Control (0.65 ±0.05 m·s) observed. Additionally, individual repetition mean concentric velocity ranged from possibly (repetition number two: 0.79 ±0.04 vs. 0.78 ±0.04 m·s) to almost certainly (repetition number 10: 0.58 ±0.05 vs. 0.49 ±0.05 m·s) greater when provided feedback, while almost certain differences were observed in motivation, competitiveness, and perceived workload, respectively. Providing adolescent male athletes with visual kinematic information while completing resistance training is beneficial for the maintenance of barbell velocity during a training set, potentially enhancing physical performance. Moreover, these improvements were observed alongside increases in motivation, competitiveness and perceived workload providing insight into the underlying mechanisms responsible for the performance gains observed. Given the observed maintenance of barbell velocity during a training set, practitioners can use this technique to manipulate training outcomes during resistance training.

Based on these findings, both 10-Hz GPS and timing gates provide valid measures of 40-m V assessment compared with a radar gun. However, as error did exist between measures, the same testing protocol should be used when assessing 40-m V over time. Furthermore, in light of the above results, it is recommended that when assessing changes in GPS-derived V over time, practitioners should use the same unit for each player and perform the analysis with the same software, preferably Catapult Openfield.

This study established the between-day reliability and sensitivity of a countermovement jump (CMJ), plyometric push-up, wellbeing questionnaire and whole blood creatine kinase concentration [CK] in elite male youth rugby union players. The study also established the between-day reliability of 1, 2 or 3 CMJ and plyometric push-up attempts. Twenty-five players ]completed tests on 2 occasions separated by 5 days (of rest). Between-day typical error (TE), coefficient of variation (CV) and smallest worthwhile change (SWC) were calculated for the wellbeing questionnaire, [CK] and CMJ and plyometric push-up metrics (peak/mean power, peak/mean force, height, flight-time and flight-time to contraction-time ratio) for 1 maximal effort or taking the highest score from 2 or 3 maximal efforts. The results from this study would suggest that CMJ mean power (2 or 3 attempts), peak force or mean force, and plyometric push-up mean force (from 2 or 3 attempts) should be used for assessing lower-and upper-body neuromuscular function respectively, due to both their acceptable reliability (CV<5%) and good sensitivity (CV 5% (7.1% and 26.1% respectively) and poor sensitivity (CV>SCW). The findings from this study can be used when interpreting fatigue markers to make an objective decision about a player's readiness to train or compete.

Adolescent rugby players benefit from the implementation of resistance training. However resistance training practices and how they influence short-term physical change is unknown.Therefore the purpose of this study was to quantify resistance training practices, evaluate physical development, and relate these changes to resistance training variables across 12-weeks in adolescent rugby union players. Thirty-five male adolescent rugby union players participated in the study with subjects completing an anthropometric and physical testing battery pre-and post-a 12-week in-season mesocycle. Subjects recorded resistance training frequency, exercises, repetitions, load, minutes, and rating of perceived exertion for each session using weekly training diaries during the 12-week period. Paired sample t-tests and Cohen's d effect sizes were used to assess change, while Pearson correlation coefficients assessed relationships between variables. Resistance training practices were variable, while significant (p ≤0.05) improvements in body mass, countermovement jump (CMJ) height, front squat, bench press, and chin up strength were observed. Resistance training volume load had moderate to strong relationships with changes in CMJ (r =0.71), chin up (r =0.73) and bench press (r =0.45). Frequency of upper and lower body compound exercises had significant moderate to large relationships with changes in CMJ (r =0.68), chin up (r =0.65), and bench press (r =0.41). Across a 12-week in-season period, adolescent rugby union players have varying resistance training practices, while anthropometric and physical characteristics appear to improve. Given the observed relationships, increased volume loads through the implementation of free-weight compound exercises could be an effective method for improving physical qualities in young rugby players.Rugby union, resistance training, strength, power

PurposeInvestigate the acute and short-term (i.e., 24 h) effects of traditional (TRAD), superset (SS), and tri-set (TRI) resistance training protocols on perceptions of intensity and physiological responses.MethodsFourteen male participants completed a familiarisation session and three resistance training protocols (i.e., TRAD, SS, and TRI) in a randomised-crossover design. Rating of perceived exertion, lactate concentration ([Lac]), creatine kinase concentration ([CK]), countermovement jump (CMJ), testosterone, and cortisol concentrations was measured pre, immediately, and 24-h post the resistance training sessions with magnitude-based inferences assessing changes/differences within/between protocols.ResultsTRI reported possible to almost certainly greater efficiency and rate of perceived exertion, although session perceived load was very likely lower. SS and TRI had very likely to almost certainly greater lactate responses during the protocols, with changes in [CK] being very likely and likely increased at 24 h, respectively. At 24-h post-training, CMJ variables in the TRAD protocol had returned to baseline; however, SS and TRI were still possibly to likely reduced. Possible increases in testosterone immediately post SS and TRI protocols were reported, with SS showing possible increases at 24-h post-training. TRAD and SS showed almost certain and likely decreases in cortisol immediately post, respectively, with TRAD reporting likely decreases at 24-h post-training.ConclusionsSS and TRI can enhance training efficiency and reduce training time. However, acute and short-term physiological responses differ between protocols. Athletes can utilise SS and TRI resistance training, but may require additional recovery post-training to minimise effects of fatigue.

Limited research has compared the physical qualities of adolescent rugby union (RU) players across differing playing standards. This study therefore compared the physical qualities of academy and school Under-18 RU players. One-hundred and eighty-four (professional regional academy, n = 55 school, n = 129) male RU players underwent a physical testing battery to quantify height, body mass, strength (bench press and pull-up), speed (10, 20 and 40 m), 10 m momentum (calculated; 10 m velocity * body mass) and a proxy measure of aerobic fitness (Yo-Yo Intermittent Recovery Test Level 1; IRTL1). The practical significance of differences between playing levels were assessed using magnitude-based inferences. Academy players were taller (very likely small), heavier (likely moderate) and stronger (bench press possibly large; pull-up plus body mass likely small) than school players. Academy players were faster than school players over 20 and 40 m (possibly and likely small), although differences in 10 m speed were not apparent (possibly trivial). Academy players displayed greater 10 m momentum (likely moderate) and greater IRTL1 performance (likely small) than school players. These findings suggest that body size, strength, running momentum, 40 m speed and aerobic fitness contribute to a higher playing standard in adolescent rugby union.

Background: Post-match fatigue has yet to be investigated in academy rugby union players. Objectives: To determine the magnitude of change in upper-(plyometric push-up (PP) flight-time) and lower-body (countermovement jump (CMJ) mean power) neuromuscular function (NMF), whole blood creatine kinase (CK) and perception of well-being following a competitive match in academy rugby union players. Methods: Fourteen academy rugby union players participated in the study. Measures were taken 2 h pre-match (baseline) and immediately post-match. Further testing was also undertaken at 24-, 48-and 72 h respectively post-match. Changes in measures from baseline were determined using magnitude-based inferences.

The purpose of this study was to quantify the physical demands of representative adolescent rugby union match-play and investigate the difference between playing positions and age groups. Players (n=112) were classified into 6 groups by playing position (forwards and backs) and age group (U16, U18, U20). The physical demands were measured using microsensor-based technology and analysed using magnitude based inferences to assess practical importance. Backs had a greater relative distance (except U16s) and a greater highspeed running distance per minute than forwards, with the magnitude of difference between the positions becoming larger in older age groups. Forwards had higher values of PlayerLoad TM per minute (accumulated accelerations from the three axes of movement) and PlayerLoad TM slow per minute (accumulated accelerations from the three axes of movement where velocity is <2 m.s -1 ) than backs at all age groups. Relative distance, low-and highspeed running per minute all had a trend to be lower in older age groups for both positions.PlayerLoad TM per minute was greater in U18 than U16 and U20 for both positions.PlayerLoad TM slow per minute was greater for older age groups besides the U18 and U20 comparisons, which were unclear. The contrasts in physical demands experienced by different positions reinforce the need for greater exposure to sprinting and collision based activity for backs and forwards, respectively. Given PlayerLoad TM metrics peak at U18 and locomotor demands seem to be lower in older ages, the demands of representative adolescent rugby union do not seem to be greater at U20 as expected.