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To review the quality of reporting and identify the content of exercise interventions prescribed for hamstring strain injury (HSI) rehabilitation in the scientific literature from 2010 to 2020.Scoping review.We searched the bibliometric databases Web of Science, CINAHL, SPORTDiscus, Scopus, Cochrane Library, MEDLINE, and Embase.Original research articles (randomized controlled trials and cohort studies) published from 2010 to 2020 that described an exercise rehabilitation intervention for participants with acute HSIs were included. Injuries must have been confirmed within 7 days of occurrence via clinical assessment and/or diagnostic imaging.The quality of reporting, in terms of completeness of exercise intervention description, was evaluated using the Consensus on Exercise Reporting Template (CERT), and the content of interventions was categorized into exercise types.Fourteen studies were included; exercise intervention quality of reporting was moderate in 3 studies and low in 11 studies. Using the 19-item CERT, an average of 8.8 items (range, 4-14) were reported across all studies. Two studies reported sufficient exercise content and progression information to allow replication. Exercises categorized as hamstring flexibility, hamstring strength, running related, and non-hamstring specific were prescribed in 13, 11, 10, and 10 studies, respectively. Half of the included studies incorporated all 4 exercise types in their exercise interventions.There is a wide variety of exercise interventions applied in published research that has addressed HSI rehabilitation. Researchers must improve reporting quality to support other professionals in replicating exercise interventions and help practitioners to effectively implement research in practice.

Edwards, T, Weakley, J, Woods, CT, Breed, R, Benson, AC, Suchomel, TJ, and Banyard, HG. Comparison of countermovement jump and squat jump performance between 627 state and non-state representative junior Australian football players. J Strength Cond Res XX(X): 000-000, 2022-This cross-sectional study investigated differences in lower-body power of state and nonstate representative junior Australian football (AF) players through countermovement jump (CMJ) and squat jump (SJ) performance. A total of 627 players performed the CMJ and SJ at the end of the preseason phase over a 2-week period, with each player grouped according to their age (under 18 [U18] or under 16 [U16]), and highest competition level played (state representation and nonstate representation). One-way multivariate analysis of variance (MANOVA), follow up ANOVA's, and Cohen's d effect sizes were used to identify significant main effects and between-group differences. Statistical significance was set at α0.05. Significant small-to-moderate effect size differences were observed between competition level, with state U18 and U16 players recording greater CMJ and SJ height, and peak power (PP), compared with their nonstate representative peers, respectively. Similarly, significant small-to-moderate effect size differences existed between age groups, with nonstate U18 players recording greater CMJ and SJ height and PP than nonstate U16 counterparts. However, state U18 and state U16 only differed in CMJ PP. No differences were found between competition level or age groups for the difference between CMJ and SJ jump height (CMJSJdiff). Together, these findings suggest that state and nonstate representative junior AFs may have a similar ability to use the stretch-shortening cycle, despite state representative players jumping higher in the CMJ and SJ.

Recent evolutionary computations predict that a few percent of massive OB stars in binary systems should have a dormant BH companion. Despite several reported X-ray quiet OB+BH systems over the last couple of years, finding them with certainty remains challenging. These have great importance as they can be gravitational wave (GW) source progenitors, and are landmark systems in constraining supernova kick physics. This work aims to characterise the hidden companions to the single-lined spectroscopic binaries (SB1s) in the B star population of the young open Galactic cluster NGC 6231 to find candidate systems for harbouring compact object companions. With the orbital solutions for each SB1 previously constrained, we applied Fourier spectral disentangling to multi-epoch optical VLT/FLAMES spectra of each target to extract a potential signature of a faint companion, and to identify newly disentangled double-lined spectroscopic binaries (SB2s). For targets where the disentangling does not reveal any signature of a stellar companion, we performed atmospheric and evolutionary modelling on the primary to obtain constraints on the unseen companion. Seven newly classified SB2 systems with mass ratios down to near 0.1 were identified. From the remaining targets, for which no faint companion could be extracted from the spectra, four are found to have companion masses in the predicted mass ranges of neutron stars (NSes) and BHes. Two of these have companion masses between 1 and 3.5 $M_{\odot}$, making them potential hosts of NSes (or lower mass main sequence stars). The other two are between 2.5 to 8 $M_{\odot}$ and 1.6 and 26 $M_{\odot}$, respectively, and so are identified as candidates for harbouring BH companions. However, unambiguous identification of these systems as X-ray quiet compact object harbouring binaries requires follow up observations., Submitted to A&A

This study aimed to investigate the influence of chronological age and maturation status on sprint acceleration characteristics in junior Australian football (AF) players. Biological maturity of 109 subjects was assessed and subjects were grouped according to predicted years from peak height velocity (PHV) (pre-, mid-, and post-PHV) and chronological age (13 years, 14 years, and 15 years). A one-way multivariate analysis of variance and magnitude-based decisions were used to determine between-group differences. Instantaneous velocity was measured during two maximal 30m sprints via radar gun with the velocity-time data used to derive the force, velocity, and power characteristics. Chronologically, the greatest differences were observed between the 13 and 14 year old groups with the latter group producing likely greater relative maximum power (Pmax) (ES[effect size]=0.44) and theoretical maximal velocity (V0) (ES=0.49). The post-PHV group likely demonstrated a greater ability to apply force at faster velocity (V0; ES=0.59) and orient the force in a horizontal direction (Drf%; ES=-0.49) than the mid-PHV group. No differences in relative theoretical maximal force (F0) were observed between groups. Considering the findings, practitioners should aim to improve relative lower limb strength through heavy sled push or sled pulls and traditional strength training exercises to improve relative F0.

Context. The fate of a massive star during the latest stages of its evolution is highly dependent on its mass-loss rate/geometry and therefore knowing the geometry of the circumstellar material close to the star and its surroundings is crucial. Aims. We aim to study the nature (i.e. geometry, rates) of mass-loss episodes. In this context, yellow hypergiants are great targets. Methods. We analyse a large set of optical/near-infrared data, in spectroscopic and photometric (X-shooter/VLT), spectropolarimetric (ISIS/WHT), and interferometric GRAVITY-AMBER/VLTI) modes, toward the yellow hypergiant IRAS 17163-3907. We present the first model-independent reconstructed images of IRAS 17163-3907 at these wavelengths at milli-arcsecond scales. Lastly, we apply a 2D radiative transfer model to fit the dereddened photometry and the radial profiles of published VISIR images at 8.59 {\mu}m, 11.85 {\mu}m and 12.81 {\mu}m simultaneously, adopting the revised Gaia distance (DR2). Results. The interferometric observables around 2 {\mu}m show that the Br{\gamma} emission is more extended and asymmetric than the Na i and the continuum emission. In addition to the two known shells surrounding IRAS 17163-3907 we report on the existence of a third hot inner shell with a maximum dynamical age of only 30 yr. Conclusions. The interpretation of the presence of Na i emission at closer distances to the star compared to Br{\gamma} has been a challenge in various studies. We argue that the presence of a pseudophotosphere is not needed, but it is rather an optical depth effect. The three observed distinct mass-loss episodes are characterised by different mass-loss rates and can inform the theories on mass-loss mechanisms, which is a topic still under debate. We discuss these in the context of photospheric pulsations and wind bi-stability mechanisms., Comment: 26 pages, 22 Figures, 6 tables, accepted for publication in A&A. Original abstract will be available after publication

Edwards, T, Piggott, B, Banyard, HG, Haff, GG, and Joyce, C. The effect of a heavy resisted sled-pull mesocycle on sprint performance in junior Australian football players. J Strength Cond Res XX(X): 000-000, 2022-This study assessed the effect of heavy resisted sled-pull training on sprint times and force, velocity, and power characteristics in junior Australian football players. Twenty-six athletes completed a 6-week resisted sled-pull training intervention which included 10 training sessions and 1-week taper. Instantaneous velocity during 2 maximal 30 m sprints was recorded 1 week before and 1 week after the intervention with a radar gun. Velocity-time data were used to derive sprint performance and force, velocity, and power characteristics. A paired t-test assessed the within-group differences between preintervention and postintervention testing. Statistical significance was accepted at p ≤ 0.05. Hedges' g effect sizes (ESs) were used to determine the magnitude of change in dependent variables. Maximum velocity (ES = 1.33) and sprint times at all distances (ES range 0.80-1.41) significantly improved after heavy resisted sled-pull training. This was reflected in sprint force, velocity, and power characteristics with significant improvements in relative theoretical force (ES = 0.63), theoretical velocity (ES = 0.99), relative maximum power (ES = 1.04), and ratio of horizontal to vertical force (ES = 0.99). Despite the multifactorial nature of training and competing physical demands associated with preseason training, these findings imply that a short, resisted sled-pull training mesocycle may improve sprint performance and underlying force, velocity, and power characteristics in junior athletes.

The aim of this study was to compare the force, velocity and power profiles of a maximal sprint acceleration through different competition levels of the Australian Football (AF) participation pathway. One hundred and sixty-two junior AF athletes across five competition levels including State under 18's (ST 18), State under 16's (ST 16), local under 18's (LOC 18), local under 15's (LOC 15), and local under 14's (LOC 14) participated in this cross-sectional study. Velocity-time data from maximal sprint accelerations were analysed to derive athlete's sprint acceleration characteristics and split times. ST 18 showed a more force-orientated profile than the LOC 18 with moderate differences in relative theoretical maximal force (F0) (7.54%), absolute F0 (10.51%), and slope of the force-velocity relationship (Sf-v) (9.27%). Similarly, small differences were found between ST 18 and ST 16 in relative F0 (4.79%) and Sf-v (6.28%). Moderate to extremely large differences were observed between players competing in older (ST 18, LOC 18, ST 16) compared to younger (LOC 15, LOC 14) competition levels highlighting the potential influence of biological maturation. It is recommended that practitioners working with junior AF players to consider developing a force-orientated sprint acceleration profile to improve sprinting performance.

This study sought to longitudinally and retrospectively determine the relationship between professional career attainment and the development of anthropometric and physical qualities in junior Australian footballers. Eighty adolescent male Australian footballers from a single state academy previously selected onto an under 16 s talent development squad were classified by career attainment (professional team selection; n = 17 and non-selected; n = 63). Physical and anthropometric tests were conducted at the end of preseason during participation in under 16 and under 18 competitions. Tests included standing height, mass, stationary countermovement jumps, dynamic vertical jumps, 20-m sprints, agility and 20 m multistage fitness test. Both groups significantly improved all performance measures between the under 16 and under 18 levels. Athletes selected onto a professional team possessed significantly quicker 20-m sprint outcomes than non-selected athletes at both under 16 and under 18 levels, highlighting the importance of this physical capacity within talent development programmes. Binary logistic regression was unable to predict an effect of any measures on career attainment. An inability of the binary logistic regression to identify qualities predictive of long-term career success likely highlights limitations associated with utilising unidimensional models of assessment in talent identification practices. As such, development coaches and sport scientists should be aware that while physical capacities play a role in career attainment outcomes, other factors, such as tactical understanding and technical skill are also likely to be impactful.

This study investigated the return to baseline of movement velocity and maximal strength following a strength-orientated session and power-orientated session in the free-weight back-squat performed...

Two scenarios have been proposed to match the existing observational constraints of the object HR 6819. The system could consist of a close inner B-type giant plus a black hole (BH) binary with an additional Be companion in a wide orbit. Alternatively, it could be a binary composed of a stripped B star and a Be star in a close orbit. Either scenario makes HR 6819 a cornerstone object as the stellar BH closest to Earth, or as an example of an important transitional, non-equilibrium phase for Be stars with solid evidence for its nature. We aimed to distinguish between the two scenarios for HR 6819. Both models predict two luminous stars but with very different angular separations and orbital motions. Therefore, the presence of bright sources in the 1-100 milliarcsec (mas) regime is a key diagnostic for determining the nature of the HR 6819 system. We obtained new high-angular resolution data with VLT/MUSE and VLTI/GRAVITY of HR 6819. The MUSE data are sensitive to bright companions at large scales, whilst the interferometric GRAVITY data are sensitive down to separations on mas scales and large magnitude differences. The MUSE observations reveal no bright companion at large separations and the GRAVITY observations indicate the presence of a stellar companion at an angular separation of ~1.2 mas that moves on the plane of the sky over a timescale compatible with the known spectroscopic 40-day period. We conclude that HR 6819 is a binary system and that no BH is present in the system. The unique nature of HR 6819, and its proximity to Earth make it an ideal system for quantitatively characterising the immediate outcome of binary interaction and probing how Be stars form., 16 pages, 11 figures, subject of ESO press release eso2204

Context. It is well known that massive O stars are frequently (if not always) found in binary or higher-order multiple systems, but this fact has been less robustly investigated for the lower mass range of the massive stars, represented by B-type stars. Obtaining the binary fraction and orbital parameter distributions of B-type stars is crucial to understand the impact of multiplicity on the archetypal progenitor of core-collapse supernovae as well as to properly investigate formation channels for gravitational wave progenitors. Aims. This work aims to characterise the multiplicity of the B star population of the young open cluster NGC 6231 through multi-epoch optical spectroscopy of 80 B-type stars. Methods. We analyse 31 FLAMES/GIRAFFE observations of 80 B-type stars, monitoring their radial velocities (RVs) and performing a least-squares spectral analysis (Lomb-Scargle) to search for periodicity in those stars with statistically significant variability in their RVs. Results. We constrained an observed spectroscopic binary fraction of 33 ± 5% for the B-type stars of NGC 6231, with a first order bias correction giving a true spectroscopic binary fraction of 52 ± 8%. Out of 27 B-type binary candidates, we obtained orbital solutions for 20 systems: 15 single-lined (SB1) and five double-lined spectroscopic binaries (SB2s). We present these orbital solutions and the orbital parameter distributions associated with them. Conclusions. Our results indicate that Galactic B-type stars are less frequently found in binary systems than their more massive O-type counterparts, but their orbital properties generally resemble those of B- and O-type stars in both the Galaxy and Large Magellanic Cloud.

This investigation aimed to compare the maximal sprint acceleration profiles of drafted and non-drafted elite junior Australian football (AF) players. Nineteen players (10 drafted and 9 non-drafted) from an elite junior AF state team participated in this study. Instantaneous velocity was measured via radar gun during maximal 30 m sprints. The velocity-time data were analysed to derive individual force-velocity-power characteristics and sprint times. No significant differences existed between groups, however drafted players reached moderately faster maximum velocity (Hedges' g = 0.70 [-0.08; 1.48] and theoretical maximum velocity (g = 0.65 [-0.13; 1.42]) than non-drafted players indicating a superior ability to apply higher amounts of force at increasing sprinting velocity. Further, drafted players produced moderately higher absolute theoretical maximum force (g = 0.72 [-0.06; 1.50]) and absolute maximum power (g = 0.83 [0.04; 1.62]) which reflects their moderately higher body mass (g = 0.61[-0.16;1.38]). Although not significant, in this sample of elite junior AF players, those drafted into the AFL displayed greater absolute sprint acceleration characteristics and maximal velocity capabilities than their non-drafted counterparts (moderate effect size). Whether force-velocity-power characteristics can be more beneficial in differentiating sprint performance of elite junior Australian footballers compared to the traditional sprint time approach warrants further investigation with a larger sample size.

Edwards, T, Banyard, HG, Piggott, B, Haff, GG, and Joyce, C. The reliability and minimal detectable change of sprint times and force-velocity-power characteristics. J Strength Cond Res XX(X): 000-000, 2021-Research has not yet provided critical information for practitioners to determine the minimal detectable change (MDC) in sprint times or force-velocity-power characteristics. Therefore, the aim of this study was to establish the interday reliability and MDC of sprint times and sprint force-velocity-power characteristics in junior Australian football (AF) players. Seventeen players were assessed using a radar device that recorded instantaneous velocity during 3 maximal 30-m sprint accelerations performed on 2 nonconsecutive days. Sprint force, velocity, and power characteristics were derived through inverse dynamics applied to the raw velocity-time data. Relative and absolute reliability was determined by calculating the intraclass correlation coefficient (ICC), coefficient of variation (CV), and MDC. Data analysis was assessed for (a) the first trial, (b) the best trial (the fastest 30-m split time), (c) the average of the first 2 trials, and (d) the average of all 3 trials from each testing session. The main findings were (a) absolute theoretical maximum force (F0), theoretical maximal velocity (V0), absolute and relative maximum power (Pmax), maximum ratio of force (RFmax), maximum velocity (Vmax), and all sprint distance times (5-30 m) displayed acceptable reliability (CV 0.75) and 2) the average of 2 and 3 trials was the best method of establishing reliable sprint times and force-velocity-power characteristics between sessions. This study provides important information for practitioners to determine the MDC in sprint times and force-velocity-power characteristics that allow coaches to identify true changes in performance.

Observations of massive stars in young open clusters (< ~8 Myr) have shown that a majority of them are in binary systems, most of which will interact during their life. Populations of massive stars older than ~20 Myr allow us to probe the outcome of such interactions after many systems have experienced mass and angular momentum transfer. Using multi-epoch integral-field spectroscopy, we investigate the multiplicity properties of the massive-star population in NGC 330 (~40 Myr) in the Small Magellanic Cloud to search for imprints of stellar evolution on the multiplicity properties. From six epochs of VLT/MUSE observations supported by adaptive optics we extract spectra and measure radial velocities for stars brighter than F814W = 19. We identify single-lined spectroscopic binaries through significant RV variability as well as double-lined spectroscopic binaries, and quantify the observational biases for binary detection. The observed spectroscopic binary fraction is 13.2+/-2.0 %. Considering period and mass ratio ranges from log(P)=0.15-3.5, and q = 0.1-1.0, and a representative set of orbital parameter distributions, we find a bias-corrected close binary fraction of 34 +8 -7 %. This seems to decline for the fainter stars, which indicates either that the close binary fraction drops in the B-type domain, or that the period distribution becomes more heavily weighted towards longer orbital periods. Both fractions vary strongly in different regions of the color-magnitude diagram which probably reveals the imprint of the binary history of different groups of stars. We provide the first homogeneous RV study of a large sample of B-type stars at a low metallicity. The overall bias-corrected close binary fraction of B stars in NGC 330 is lower than the one reported for younger Galactic and LMC clusters. More data are needed to establish whether this result from an age or a metallicty effect., 19 page (incl. appendix), 10 figures, 4 tables, accepted for publication in A&A

Hughes, LJ, Banyard, HG, Dempsey, AR, and Scott, BR. Using a load-velocity relationship to predict one repetition maximum in free-weight exercise: a comparison of the different methods. J Strength Cond Res 33(9): 2409-2419, 2019-The purpose of this study was to investigate the reliability and validity of predicting 1 repetition maximum (1RM) in trained individuals using a load-velocity relationship. Twenty strength-trained men (age: 24.3 ± 2.9 years, height: 180.1 ± 5.9 cm, and body mass: 84.2 ± 10.5 kg) were recruited and visited the laboratory on 3 occasions. The load-velocity relationship was developed using the mean concentric velocity of repetitions performed at loads between 20 and 90% 1RM. Predicted 1RM was calculated using 3 different methods discussed in existing research: minimal velocity threshold 1RM (1RMMVT), load at zero velocity 1RM (1RMLD0), and force-velocity 1RM methods (1RMFV). The reliability of 1RM predictions was examined using intraclass correlation coefficient (ICC) and coefficient of variation (CV). 1RMMVT demonstrated the highest reliability (ICC = 0.92-0.96, CV = 3.6-5.0%), followed by 1RMLD0 (ICC = 0.78-0.82, CV = 8.2-8.6%) and 1RMFV (ICC = -0.28 to 0.00, CV = N/A). Both 1RMMVT and 1RMLD0 were very strongly correlated with measured 1RM (r = 0.91-0.95). The only method which was not significantly different to measured 1RM was the 1RMLD0 method. However, when analyzed on an individual basis (using Bland-Altman plots), all methods exhibited a high degree of variability. Overall, the results suggest that the 1RMMVT and 1RMLD0 predicted 1RM values could be used to monitor strength progress in trained individuals without the need for maximal testing. However, given the significant differences between 1RMMVT and measured 1RM, and the high variability associated with individual predictions performed using each method, they cannot be used interchangeably; therefore, it is recommended that predicted 1RM is not used to prescribe training loads as has been previously suggested.

Purpose: This study compared kinetic and kinematic data from three different velocity-based training (VBT) sessions and a 1-repetition maximum (1RM) percent-based training (PBT) session using full-depth, free-weight back squats with maximal concentric effort. Methods: Fifteen strength-trained men performed four randomized resistance-training sessions 96-hours apart: PBT session involved five sets of five repetitions using 80%1RM; load-velocity profile (LVP) session contained five sets of five repetitions with a load that could be adjusted to achieve a target velocity established from an individualized LVP equation at 80%1RM; fixed sets 20% velocity loss threshold (FSVL20) session that consisted of five sets at 80%1RM but sets were terminated once the mean velocity (MV) dropped below 20% of the threshold velocity or when five repetitions were completed per set; variable sets 20% velocity loss threshold (VSVL20) session comprised 25-repetitions in total, but participants performed as many repetitions in a set as possible until the 20% velocity loss threshold was exceeded. Results: When averaged across all repetitions, MV and peak velocity (PV) were significantly (p

Aims. To search for these rare objects, we study 32 Galactic O-type stars that were reported as SB1s in the literature. In our sample we include Cyg X-1, which is known to host an accreting stellar-mass BH, and HD 74194, a supergiant fast X-ray transient, in order to validate our methodology. The final goal is to characterise the nature of the unseen companions to determine if they are MS stars, stripped helium stars, triples, or compact objects such as neutron stars or stellar-mass BHs. Methods. After measuring radial velocities and deriving orbital solutions for all the systems in our sample, we performed spectral disentangling to extract putative signatures of faint secondary companions from the composite spectra. We derived stellar parameters for the visible stars and estimated the mass ranges of the secondary stars using the binary mass function. Variability observed in the photometric TESS light curves was also searched for indications of the presence of putative companions, degenerate or not. Results. In 17 of the 32 systems reported as SB1s, we extract secondary signatures, down to mass ratios of ~0.15. For the 17 newly detected double-lined spectroscopic binaries (SB2s), we derive physical properties of the individual components and discuss why they have not been detected as such before. Among the remaining systems, we identify nine systems with possible NS or low-mass MS companions. For Cyg X-1 and HD 130298, we are not able to extract any signatures for the companions, and the minimum masses of their companions are estimated to be about 7Msun. Our simulations show that secondaries with such a mass should be detectable from our dataset, no matter their nature: MS stars, stripped helium stars or even triples. While this is expected for Cyg X-1, confirming our methodology, our simulations also strongly suggest that HD 130298 could be another candidate to host a stellar-mass BH., 20 pages (31 pages of Appendix), 19 figures, A&A in press. The abstract is shorter than in the paper, and some figures, and tables have been cut in the paper

Purpose: This study compared pooled against individualized load–velocity profiles (LVPs) in the free-weight back squat and power clean. Methods: A total of 10 competitive weightlifters completed baseline 1-repetition maximum assessments in the back squat and power clean. Three incremental LVPs were completed, separated by 48 to 72 hours. Mean and peak velocity were measured via a linear-position transducer (GymAware). Linear and nonlinear (second-order polynomial) regression models were applied to all pooled and individualized LVP data. A combination of coefficient of variation (CV), intraclass correlation coefficient, typical error of measurement, and limits of agreement assessed between-subject variability and within-subject reliability. Acceptable reliability was defined a priori as intraclass correlation coefficient > .7 and CV Results: Very high to practically perfect inverse relationships were evident in the back squat (r = .83–.96) and power clean (r = .83–.89) for both regression models; however, stronger correlations were observed in the individualized LVPs for both exercises (r = .85–.99). Between-subject variability was moderate to large across all relative loads in the back squat (CV = 8.2%–27.8%) but smaller in the power clean (CV = 4.6%–8.5%). The power clean met our criteria for acceptable reliability across all relative loads; however, the back squat revealed large CVs in loads ≥90% of 1-repetition maximum (13.1%–20.5%). Conclusions: Evidently, load–velocity characteristics are highly individualized, with acceptable levels of reliability observed in the power clean but not in the back squat (≥90% of 1-repetition maximum). If practitioners want to adopt load–velocity profiling as part of their testing and monitoring procedures, an individualized LVP should be utilized over pooled LVPs.

Velocity-based training (VBT) is a contemporary method of resistance training that enables accurate and objective prescription of resistance training intensities and volumes. This review provides an applied framework for the theory and application of VBT. Specifically, this review gives detail on how to: use velocity to provide objective feedback, estimate strength, develop load-velocity profiles for accurate load prescription, and how to use statistics to monitor velocity. Furthermore, a discussion on the use of velocity loss thresholds, different methods of VBT prescription, and how VBT can be implemented within traditional programming models and microcycles is provided.

Purpose: To compare the effects of velocity-based training (VBT) and 1-repetition-maximum (1RM) percentage-based training (PBT) on changes in strength, loaded countermovement jump (CMJ), and sprint performance. Methods: A total of 24 resistance-trained males performed 6 weeks of full-depth free-weight back squats 3 times per week in a daily undulating format, with groups matched for sets and repetitions. The PBT group lifted with fixed relative loads varying from 59% to 85% of preintervention 1RM. The VBT group aimed for a sessional target velocity that was prescribed from pretraining individualized load–velocity profiles. Thus, real-time velocity feedback dictated the VBT set-by-set training load adjustments. Pretraining and posttraining assessments included the 1RM, peak velocity for CMJ at 30%1RM (PV-CMJ), 20-m sprint (including 5 and 10 m), and 505 change-of-direction test (COD). Results: The VBT group maintained faster (effect size [ES] = 1.25) training repetitions with less perceived difficulty (ES = 0.72) compared with the PBT group. The VBT group had likely to very likely improvements in the COD (ES = −1.20 to −1.27), 5-m sprint (ES = −1.17), 10-m sprint (ES = −0.93), 1RM (ES = 0.89), and PV-CMJ (ES = 0.79). The PBT group had almost certain improvements in the 1RM (ES = 1.41) and possibly beneficial improvements in the COD (ES = −0.86). Very likely favorable between-groups effects were observed for VBT compared to PBT in the PV-CMJ (ES = 1.81), 5-m sprint (ES = 1.35), and 20-m sprint (ES = 1.27); likely favorable between-groups effects were observed in the 10-m sprint (ES = 1.24) and nondominant-leg COD (ES = 0.96), whereas the dominant-leg COD (ES = 0.67) was possibly favorable. PBT had small (ES = 0.57), but unclear differences for 1RM improvement compared to VBT. Conclusions: Both training methods improved 1RM and COD times, but PBT may be slightly favorable for stronger individuals focusing on maximal strength, whereas VBT was more beneficial for PV-CMJ, sprint, and COD improvements.

Eclipsing binary systems with components that pulsate in gravity modes ($g$ modes) allow for simultaneous and independent constraints of the chemical mixing profiles of stars. We aim to assemble a sample of $g$-mode pulsators in detached eclipsing binaries with the purpose of finding good candidates for future evolutionary and asteroseismic modelling. In addition, we present a case study of the eclipsing binary KIC9850387, identified as our most promising candidate. We selected all of the detached eclipsing binaries in the Kepler eclipsing binary catalogue and performed a visual inspection to determine the presence and density of $g$ modes, and the presence of $g$-mode period-spacing patterns in their frequency spectra. We then characterised our sample based on their $g$-mode pulsational parameters and binary and atmospheric parameters. A spectroscopic follow-up of KIC9850387 was then performed. We then performed spectral disentangling followed by atmospheric modelling and abundance analysis for the primary star. We utilised an iterative approach to simultaneously optimise the pulsational and eclipse models, and subsequently performed an analysis of the pressure- ($p$-) and $g$-mode pulsational frequencies. We compiled a sample of 93 Kepler eclipsing binary stars with $g$-mode pulsating components and identified clear $g$-mode period-spacing patterns in the frequency spectra of seven of these systems. We found that the $g$-mode pulsational parameters and the binary and atmospheric parameters of our sample are weakly correlated at best. We find that the eclipsing binary KIC9850387 is a double-lined spectroscopic binary in a near-circular orbit with an intermediate-mass primary, and a solar-like secondary. We find $\ell=1$ and $\ell=2$ period-spacing patterns in the frequency spectrum of KIC9850387 spanning more than ten radial orders each., 27 pages, 14 figures, accepted for publication in A&A

ispartof: Nature vol:580 issue:7805 pages:E11-E15 ispartof: location:England status: published

Appleby, BB, Banyard, H, Cormack, SJ, and Newton, RU. Validity and reliability of methods to determine barbell displacement in heavy back squats: Implications for velocity-based training. J Strength Cond Res 34(11): 3118-3123, 2020-The purpose of this study was to investigate the validity and reliability of methods for determining barbell displacement during heavy back squats. Twelve well-trained rugby union players (mean ± SD 1 repetition maximum [1RM] 90° squat = 196.3 ± 29.2 kg) completed 2 sets of 2 repetitions at 70, 80, and 90% of 1RM squats. Barbell displacement was derived from 3 methods across 4 load categories (120-129, 140-149, 160-169, and 180-189 kg) including: a (a) linear position transducer (LPT) attached 65 cm left of barbell center, (b) 3D motion analysis tracking of markers attached to either end of a barbell, and (c) cervical marker (C7) (criterion measurement). Validity was calculated using the typical error of the estimate as a coefficient of variation (CV%) ±90% confidence interval (CI), mean bias as a percentage, and the Pearson product moment correlation (r). Intraday reliability was calculated using the intraclass correlation coefficient and the typical error expressed as a percentage of CV% ±90% (CI). Mean displacement for C7, LPT, and the barbell ends was 520, 529, and 550-564 mm, respectively. Validity of the LPT compared with the criterion was acceptable (CV% = 2.1-3.0; bias = 0.9-1.5%; r = 0.96-0.98), whereas that of the barbell ends was less (CV% = 2.7-7.5; bias = 4.9-11.2%; r = 0.71-0.97). The CV% reliability of the C7 marker across the load categories was 6.6%, the LPT 6.6%, and the barbell ends between 5.9 and 7.2%. Despite reliable measures, overestimation of displacement occurs as the tracking location moves to the barbell ends in weighted back squats. The LPT demonstrated high validity to the criterion and high trial-to-trial reliability.

Weakley, J, Wilson, K, Till, K, Banyard, H, Dyson, J, Phibbs, P, Read, D, and Jones, B. Show me, tell me, encourage me: The effect of different forms of feedback on resistance training performance. J Strength Cond Res 34(11): 3157-3163, 2020-When performing resistance training, verbal kinematic feedback and visual kinematic feedback are known to enhance performance. In addition, providing verbal encouragement can assist in the attenuation of fatigue. However, the effects of these forms of feedback have never been compared. Consequently, this study aimed to quantify the effects of verbal kinematic feedback and visual kinematic feedback, and verbal encouragement on barbell velocity during the back squat. Furthermore, changes in performance were related to individual-reported conscientiousness. Twelve semiprofessional rugby union players volunteered to participate in the study that consisted of the subjects completing a set of the barbell back squat across 4 conditions (i.e., no-feedback [control], verbal feedback of kinematic information [verbal], visual feedback of kinematic information [visual], and verbal encouragement [encouragement]). In addition, participants completed a questionnaire before the study to assess conscientiousness. Magnitude-based inferences were used to assess differences between conditions, whereas Spearman's rank correlation coefficient was used to assess relationships between conscientiousness and changes in barbell velocity. All 3 forms of feedback showed almost certain improvements in barbell velocity, while differences between interventions were likely to very likely trivial. Changes in barbell velocity showed small to large inverse relationships with conscientiousness. These findings suggest that practitioners should supply kinematic feedback (verbally or visually) or, when technology is not available, provide athletes with encouraging statements while resistance training. Verbal encouragement may be of greatest benefit for individuals who demonstrate low levels of conscientiousness. Given these findings, practitioners are advised to use either technology or verbal encouragement to manipulate acute training outcomes.

HR 6819 was recently proposed to be a triple system consisting of an inner B-type giant + black hole binary with an orbital period of 40d and an outer Be tertiary. This interpretation is mainly based on two inferences: that the emission attributed to the outer Be star is stationary, and that the inner star, which is used as mass calibrator for the black hole, is a B-type giant. We re-investigate the properties of HR 6819 by spectral disentangling and an atmosphere analysis of the disentangled spectra to search for a possibly simpler alternative explanation for HR 6819. Disentangling implies that the Be component is not a static tertiary, but rather a component of the binary in the 40-d orbit. The inferred radial velocity amplitudes imply an extreme mass ratio of M_2/M_1 = 15 +/- 3. We infer spectroscopic masses of 0.4$^{+0.3}_{-0.1}$ Msun and 6$^{+5}_{-3}$ Msun for the primary and secondary, which agree well with the dynamical masses for an inclination of i = 32 deg. This indicates that the primary might be a stripped star rather than a B-type giant. Evolutionary modelling suggests that a possible progenitor system would be a tight (P_i ~ 2d) B+B binary system that experienced conservative mass transfer. While the observed nitrogen enrichment of the primary conforms with the predictions of the evolutionary models, we find no indications for the predicted He enrichment. We suggest that HR 6819 is a binary system consisting of a stripped B-type primary and a rapidly-rotating Be star that formed from a previous mass-transfer event. In the framework of this interpretation, HR 6819 does not contain a black hole. Interferometry can distinguish between these two scenarios by providing an independent measurement of the separation between the visible components., Comment: Submitted to A&A, 13 pages (16 figures and 2 tables); 4 pages supplementary material (4 figures and 4 tables). Comments are welcome

Purpose: To examine the reliability of peak velocity (PV), mean propulsive velocity (MPV), and mean velocity (MV) in the development of load–velocity profiles (LVP) in the full-depth free-weight back squat performed with maximal concentric effort. Methods: Eighteen resistance-trained men performed a baseline 1-repetition maximum (1-RM) back-squat trial and 3 subsequent 1-RM trials used for reliability analyses, with 48-h intervals between trials. 1-RM trials comprised lifts from 6 relative loads including 20%, 40%, 60%, 80%, 90%, and 100% 1-RM. Individualized LVPs for PV, MPV, or MV were derived from loads that were highly reliable based on the following criteria: intraclass correlation coefficient (ICC) >.70, coefficient of variation (CV) ≤10%, and Cohen d effect size (ES) Results: PV was highly reliable at all 6 loads. MPV and MV were highly reliable at 20%, 40%, 60%, 80%, and 90% but not 100% 1-RM (MPV: ICC = .66, CV = 18.0%, ES = 0.10, SEM = 0.04 m·s−1; MV: ICC = .55, CV = 19.4%, ES = 0.08, SEM = 0.04 m·s−1). When considering the reliable ranges, almost perfect correlations were observed for LVPs derived from PV20–100% (r = .91–.93), MPV20–90% (r = .92–.94), and MV20–90% (r = .94–.95). Furthermore, the LVPs were not significantly different (P > .05) between trials or movement velocities or between linear regression versus 2nd-order polynomial fits. Conclusions: PV20–100%, MPV20–90%, and MV20–90% are reliable and can be utilized to develop LVPs using linear regression. Conceptually, LVPs can be used to monitor changes in movement velocity and employed as a method for adjusting sessional training loads according to daily readiness.

Gaudion, SL, Doma, K, Sinclair, W, Banyard, HG, and Woods, CT. Identifying the physical fitness, anthropometric and athletic movement qualities discriminant of developmental level in elite junior Australian football: implications for the development of talent. J Strength Cond Res 31(7): 1830-1839, 2017-This study aimed to identify the physical fitness, anthropometric and athletic movement qualities discriminant of developmental level in elite junior Australian football (AF). From a total of 77 players, 2 groups were defined according to their developmental level; under 16 (U16) (n = 40, 15.6 to 15.9 years), and U18 (n = 37, 17.1 to 17.9 years). Players performed a test battery consisting of 7 physical fitness assessments, 2 anthropometric measurements, and a fundamental athletic movement assessment. A multivariate analysis of variance tested the main effect of developmental level (2 levels: U16 and U18) on the assessment criterions, whilst binary logistic regression models and receiver operating characteristic (ROC) curves were built to identify the qualities most discriminant of developmental level. A significant effect of developmental level was evident on 9 of the assessments (d = 0.27-0.88; p ≤ 0.05). However, it was a combination of body mass, dynamic vertical jump height (nondominant leg), repeat sprint time, and the score on the 20-m multistage fitness test that provided the greatest association with developmental level (Akaike's information criterion = 80.84). The ROC curve was maximized with a combined score of 180.7, successfully discriminating 89 and 60% of the U18 and U16 players, respectively (area under the curve = 79.3%). These results indicate that there are distinctive physical fitness and anthropometric qualities discriminant of developmental level within the junior AF talent pathway. Coaches should consider these differences when designing training interventions at the U16 level to assist with the development of prospective U18 AF players.

Banyard, HG, Nosaka, K, and Haff, GG. Reliability and validity of the load-velocity relationship to predict the 1RM back squat. J Strength Cond Res 31(7): 1897-1904, 2017-This study investigated the reliability and validity of the load-velocity relationship to predict the free-weight back squat one repetition maximum (1RM). Seventeen strength-trained males performed three 1RM assessments on 3 separate days. All repetitions were performed to full depth with maximal concentric effort. Predicted 1RMs were calculated by entering the mean concentric velocity of the 1RM (V1RM) into an individualized linear regression equation, which was derived from the load-velocity relationship of 3 (20, 40, 60% of 1RM), 4 (20, 40, 60, 80% of 1RM), or 5 (20, 40, 60, 80, 90% of 1RM) incremental warm-up sets. The actual 1RM (140.3 ± 27.2 kg) was very stable between 3 trials (ICC = 0.99; SEM = 2.9 kg; CV = 2.1%; ES = 0.11). Predicted 1RM from 5 warm-up sets up to and including 90% of 1RM was the most reliable (ICC = 0.92; SEM = 8.6 kg; CV = 5.7%; ES = -0.02) and valid (r = 0.93; SEE = 10.6 kg; CV = 7.4%; ES = 0.71) of the predicted 1RM methods. However, all predicted 1RMs were significantly different (p ≤ 0.05; ES = 0.71-1.04) from the actual 1RM. Individual variation for the actual 1RM was small between trials ranging from -5.6 to 4.8% compared with the most accurate predictive method up to 90% of 1RM, which was more variable (-5.5 to 27.8%). Importantly, the V1RM (0.24 ± 0.06 m·s) was unreliable between trials (ICC = 0.42; SEM = 0.05 m·s; CV = 22.5%; ES = 0.14). The load-velocity relationship for the full depth free-weight back squat showed moderate reliability and validity but could not accurately predict 1RM, which was stable between trials. Thus, the load-velocity relationship 1RM prediction method used in this study cannot accurately modify sessional training loads because of large V1RM variability.

This study compared the effect of periodised versus non-periodised (NP) resistance training on neuromuscular adaptions in older adults. Forty-one apparently healthy untrained older adults (female = 21, male = 20; 70.9 ± 5.1 years; 166.3 ± 8.2 cm; 72.9 ± 13.4 kg) were recruited and randomly stratified to an NP, block periodised (BP), or daily undulating periodised (DUP) training group. Outcome measures were assessed at baseline and following a 22-week resistance training intervention (3 day week−1), including: muscle cross-sectional area (CSA), vertical jump performance, isometric and isokinetic peak torque, isometric rate of force development (RFD), and muscle activation. Thirty-three participants satisfied all study requirements and were included in analyses (female = 17, male = 16; 71.3 ± 5.4 years; 166.3 ± 8.5 cm; 72.5 ± 13.7 kg). Block periodisation, DUP, and NP resistance training induced statistically significant improvements in muscle CSA, vertical jump peak velocity, peak power and jump height, and peak isometric and isokinetic torque of the knee extensors at 60 and 180° s−1, with no between-group differences. Muscle activity and absolute RFD measures were statistically unchanged following resistance training across the entire cohort. Periodised resistance training, specifically BP and DUP, and NP resistance training are equally effective for promoting increases in muscular hypertrophy, strength, and power among untrained older adults. Consequently, periodisation strategies are not essential for optimising neuromuscular adaptations during the initial stages of resistance training in the aging population.

The aim of this study was to investigate the differences and long-term reliability in perceptual, metabolic, and neuromuscular responses to velocity loss resistance training protocols. Using a repeated, counterbalanced, crossover design, twelve team-sport athletes completed 5-sets of barbell back-squats at a load corresponding to a mean concentric velocity of ~0.70 m·s-1. On different days, repetitions were performed until a 10%, 20% or 30% velocity loss was attained, with outcome measures collected after each set. Sessions were repeated after four-weeks. There were substantial between-protocol differences in post-set differential ratings of perceived exertion (dRPE, i.e., breathlessness and leg muscles, AU) and blood lactate concentration (B[La], mmol·L-1), such that 30%>20%>10% by small to large magnitudes. Differences in post-set countermovement jump (CMJ) variables were small for most variables, such that 30%

Delgado, J, Drinkwater, EJ, Banyard, HG, Haff, GG, and Nosaka, K. Comparison between back squat, Romanian deadlift, and barbell hip thrust for leg and hip muscle activities during hip extension. J Strength Cond Res 33(10): 2595-2601, 2019-This study compared muscle activities of vastus lateralis (VL), biceps femoris (BF), and gluteus maximus (GM) during the back squat (SQ), Romanian deadlift (RDL), and barbell hip thrust (BHT) exercises performed with the same load (60 kg) and at one repetition maximum (1RM). Eight men with a minimum of 1 year's lower-body strength training experience performed the exercises in randomized order. Before each exercise, surface electromyography (EMG) was recorded during a maximal voluntary isometric contraction (MVIC) and then used to normalize to each muscle's EMG during each trial. Barbell hip thrust showed higher GM activity than the SQ (effect size [ES] = 1.39, p = 0.038) but was not significantly different from RDL (ES = 0.49, p = 0.285) at 1RM. Vastus lateralis activity at 1RM during the SQ was significantly greater than RDL (ES = 1.36, p = 0.002) and BHT (ES = 2.27, p = 0.009). Gluteus maximus activity was higher during MVIC when compared with the 60 kg load for the SQ (ES = 1.29, p = 0.002) and RDL (ES = 1.16, p = 0.006) but was similar for the BHT (ES = 0.22, p = 0.523). There were no significant differences in GM (ES = 0.35, p = 0.215) and BF activities (ES = 0.16, p = 0.791) between 1RM and MVIC for the SQ. These findings show that the RDL was equally as effective as the BHT for isolating the hip extensors, while the SQ simultaneously activated the hip and knee extensors.

Purpose: Prescribing resistance training using velocity loss thresholds can enhance exercise quality by mitigating neuromuscular fatigue. As little is known regarding performance during these protocols, we aimed to assess the effects of 10%, 20%, and 30% velocity loss thresholds on kinetic, kinematic, and repetition characteristics in the free-weight back squat. Methods: Using a randomized crossover design, 16 resistance-trained men were recruited to complete 5 sets of the barbell back squat. Lifting load corresponded to a mean concentric velocity (MV) of ∼0.70 m·s−1 (115 [22] kg). Repetitions were performed until a 10%, 20%, or 30% MV loss was attained. Results: Set MV and power output were substantially higher in the 10% protocol (0.66 m·s−1 and 1341 W, respectively), followed by the 20% (0.62 m·s−1 and 1246 W) and 30% protocols (0.59 m·s−1 and 1179 W). There were no substantial changes in MV (−0.01 to −0.02 m·s−1) or power output (−14 to −55 W) across the 5 sets for all protocols, and individual differences in these changes were typically trivial to small. Mean set repetitions were substantially higher in the 30% protocol (7.8), followed by the 20% (6.4) and 10% protocols (4.2). There were small to moderate reductions in repetitions across the 5 sets during all protocols (−39%, −31%, −19%, respectively), and individual differences in these changes were small to very large. Conclusions: Velocity training prescription maintains kinetic and kinematic output across multiple sets of the back squat, with repetition ranges being highly variable. Our findings, therefore, challenge traditional resistance training paradigms (repetition based) and add support to a velocity-based approach.

Purpose This study compared the effect of periodized versus nonperiodized (NP) resistance training (RT) on physical function and health outcomes in older adults. Methods Forty-one apparently healthy untrained older adults (women = 21, men = 20; 70.9 ± 5.1 yr; 166.3 ± 8.2 cm; 72.9 ± 13.4 kg) were recruited and randomly stratified to a NP, block periodized, or daily undulating periodized training group. Outcome measures were assessed at baseline and after a 22-wk × 3 d·wk RT intervention, including; anthropometrics, body composition, blood pressure and biomarkers, maximal strength, functional capacity, balance confidence, and quality of life. Results Thirty-three subjects satisfied all study requirements and were included in analyses (women = 17, men = 16; 71.3 ± 5.4 yr; 166.3 ± 8.5 cm; 72.5 ± 13.7 kg). The main finding was that all three RT models produced significant improvements in several physical function and physiological health outcomes, including; systolic blood pressure, blood biomarkers, body composition, maximal strength, functional capacity and balance confidence, with no between-group differences. Conclusions Periodized RT, specifically block periodization and daily undulating periodized, and NP RT are equally effective for promoting significant improvements in physical function and health outcomes among apparently healthy untrained older adults. Therefore, periodization strategies do not appear to be necessary during the initial stages of RT in this population. Practitioners should work toward increasing RT participation in the age via feasible and efficacious interventions targeting long-term adherence in minimally supervised settings.

Talent identification (TID) is a pertinent component of the sports sciences, affording practitioners the opportunity to target developmental interventions to a select few; optimising financial investments. However, TID is multi-componential, requiring the recognition of immediate and prospective performance. The measurement of athletic movement skill may afford practitioners insight into the latter component given its augmented relationship with functional sport specific qualities. It is currently unknown whether athletic movement skill is a discriminant quality in junior Australian football (AF). This study aimed to discriminate talent identified junior AF players from their non-talent identified counterparts using a fundamental gross athletic movement assessment. From a total of 50 under 18 (U18) AF players; two groups were classified a priori based on selection level; talent identified (n = 25; state academy representatives) and non-talent identified (n = 25; state-based competition representatives). Players performed a fundamental gross athletic movement assessment based on the Athletic Ability Assessment (AAA), consisting of an overhead squat, double lunge (left and right legs), single leg Romanian deadlift (left and right legs), and a push up (six movement criterions). Movements were scored across three assessment points using a three-point scale (resulting in a possible score of nine for each movement). A multivariate analysis of variance revealed significant between group effects on four of the six movement criterions (d = 0.56 – 0.87; p = 0.01 – 0.02). Binary logistic regression models and a receiver operating characteristic curve inspection revealed that the overhead squat score provided the greatest group discrimination (β(SE) = -0.89(0.44); p < 0.05), with a score of 4.5 classifying 64% and 88% of the talent identified and non-talent identified groups, respectively. Results support the integration of this assessment into contemporary talent identification approaches in junior AF, as it may provide coaches with insight into a juniors developmental potential.

Hughes, LJ, Banyard, HG, Dempsey, AR, Peiffer, JJ, and Scott, BR. Using load-velocity relationships to quantify training-induced fatigue. J Strength Cond Res 33(3): 762-773, 2019-The purpose of this study was to investigate using load-velocity relationships to quantify fluctuations in maximal strength (1 repetition maximum [1RM]), which occur as a result of training-induced fatigue. The 19 well-trained men (age: 24.3 ± 2.9 years, height: 180.1 ± 5.9 cm, body mass: 84.2 ± 10.5 kg, and squat 1RM: 151.1 ± 25.7 kg) who were recruited for this study attended 5 sessions. After baseline strength testing, individual load-velocity relationships were established using mean concentric velocity during visits 2, 4, and 5, with visit 3 consisting of a bout of fatiguing exercise (5 sets of squats performed to muscular failure with 70% 1RM). Predicted 1RM values were calculated using the minimal velocity threshold (1RMMVT), load at zero velocity (1RMLD0), and force-velocity (1RMFV) methods. Measured 1RM, maximal voluntary contractions, and perceived muscle soreness were used to examine the effects of fatigue in relation to the predicted 1RM scores. The 1RMMVT and 1RMLD0 demonstrated very strong and strong correlations with measured 1RM during each of the sessions (r = 0.90-0.96 and r = 0.77-0.84, respectively), while no strong significant correlations were observed for the 1RMFV. Further analysis using Bland-Altman plots demonstrated substantial interindividual variation associated with each method. These results suggest that load-velocity-based 1RM predictions are not accurate enough to be used for daily training load prescription, as has been previously suggested. Nevertheless, these predictions are practical to implement during an individual's warm-up and may be useful to indicate general fluctuations in performance potential, particularly if used in conjunction with other common monitoring methods.

Purpose: Feedback can enhance acute physical performance. However, its effects on physical adaptation have received little attention. Therefore, the purpose of this study was to determine the effect of feedback during a 4-wk training program on jump, sprint, and strength adaptations. Methods: A total of 28 semiprofessional male rugby union players were strength-matched into 2 groups (feedback and nonfeedback). During the 4-wk training program, the Feedback group received immediate, objective feedback on (1) mean concentric velocity during resistance training repetitions, (2) distance feedback for standing broad jumps, and (3) time for sprints. The Nonfeedback group was not provided additional information. Across the 4-wk mesocycle, subjects completed 3 strength and conditioning sessions per week. Countermovement jump, standing long jump, 10- and 20-m sprint, and 3-repetition-maximum barbell back squat and bench press were measured before and after the training intervention. Magnitude-based inferences assessed meaningful changes within and between groups. Results: The Feedback group showed small to moderate improvements in outcome measures, whereas the Nonfeedback group demonstrated trivial to small improvements. Improvements in countermovement-jump relative peak power (effect size ± 90% confidence limits: 0.34 ± 0.42), 10-m (0.20 ± 0.35) and 20-m sprints (0.40 ± 0.21), and 3-repetition-maximum back squats (0.23 ± 0.17) were possibly to likely greater for the Feedback condition than for Nonfeedback. Conclusions: Providing augmented feedback during strength and conditioning routines can enhance training adaptations compared with athletes who do not receive feedback. Consequently, practitioners should consider providing kinematic outputs, displacement, or sprint time at the completion of each repetition as athletes train.

Brock, F, Christopher, J, Harry, B, and Carl, WT. Manipulating field dimensions during small-sided games impacts the technical and physical profiles of Australian footballers. J Strength Cond Res 32(7): 2039-2044, 2018-This study investigated the effect of manipulating field dimensions on the technical and physical profiles of Australian football (AF) players during small-sided games (SSGs). A total of 40 male players (23.9 ± 3.5 years) participated in 3, five-a-side SSGs; defined as "small" (20 × 30 m; 600 m), "medium" (30 × 40 m; 1,200 m), and "large" (40 × 50 m; 2,000 m). Notational analyses enabled the quantification of technical skill indicators, whereas physical activity profiles were measured using microtechnology, resulting in 18 criterion variables. A multivariate analysis of variance modeled the main effect of field dimension on the criterion variables. A significant main effect was observed (V = 1.032; F38, 102 = 2.863; p ≤ 0.05), with the "small" and "medium" SSGs generating more turnovers and ineffective handballs relative to the "large" SSG. Furthermore, the "small" SSG generated more tackles and fewer bounces compared with the "large" SSG. The "large" SSG generated a greater absolute distance, relative distance, maximum velocity, PlayerLoad, and distance >4.16 m·s compared with the "small" and "medium" SSGs. These results provide AF coaches with insights into how task constraint manipulation impacts the technical and physical profiles of players during small-sided game-play. Thus, coaches and physical performance specialists could use this information to assist with the tactical periodization of technical complexity and physical load at different phases of the AF season.

Purpose:To examine the validity of 2 kinematic systems for assessing mean velocity (MV), peak velocity (PV), mean force (MF), peak force (PF), mean power (MP), and peak power (PP) during the full-depth free-weight back squat performed with maximal concentric effort. Methods:Ten strength-trained men (26.1 ± 3.0 y, 1.81 ± 0.07 m, 82.0 ± 10.6 kg) performed three 1-repetition-maximum (1RM) trials on 3 separate days, encompassing lifts performed at 6 relative intensities including 20%, 40%, 60%, 80%, 90%, and 100% of 1RM. Each repetition was simultaneously recorded by a PUSH band and commercial linear position transducer (LPT) (GymAware [GYM]) and compared with measurements collected by a laboratory-based testing device consisting of 4 LPTs and a force plate. Results:Trials 2 and 3 were used for validity analyses. Combining all 120 repetitions indicated that the GYM was highly valid for assessing all criterion variables while the PUSH was only highly valid for estimations of PF (r = .94, CV = 5.4%, ES = 0.28, SEE = 135.5 N). At each relative intensity, the GYM was highly valid for assessing all criterion variables except for PP at 20% (ES = 0.81) and 40% (ES = 0.67) of 1RM. Moreover, the PUSH was only able to accurately estimate PF across all relative intensities (r = .92–.98, CV = 4.0–8.3%, ES = 0.04–0.26, SEE = 79.8–213.1 N). Conclusions:PUSH accuracy for determining MV, PV, MF, MP, and PP across all 6 relative intensities was questionable for the back squat, yet the GYM was highly valid at assessing all criterion variables, with some caution given to estimations of MP and PP performed at lighter loads.

Purpose:To determine the effects of intraset rest frequency and training load on muscle time under tension, external work, and external mechanical power output during back-squat protocols with similar changes in velocity.Methods:Twelve strength-trained men (26.0 ± 4.2 y, 83.1 ± 8.8 kg, 1.75 ± 0.06 m, 1.88:0.19 one-repetition-maximum [1RM] body mass) performed 3 sets of 12 back squats using 3 different set structures: traditional sets with 60% 1RM (TS), cluster sets of 4 with 75% 1RM (CS4), and cluster sets of 2 with 80% 1RM (CS2). Repeated-measures ANOVAs were used to determine differences in peak force (PF), mean force (MF), peak velocity (PV), mean velocity (MV), peak power (PP), mean power (MP), total work (TW), total time under tension (TUT), percentage mean velocity loss (%MVL), and percentage peak velocity loss (%PVL) between protocols.Results:Compared with TS and CS4, CS2 resulted in greater MF, TW, and TUT in addition to less MV, PV, and MP. Similarly, CS4 resulted in greater MF, TW, and TUT in addition to less MV, PV, and MP than TS did. There were no differences between protocols for %MVL, %PVL, PF, or PP.Conclusions:These data show that the intraset rest provided in CS4 and CS2 allowed for greater external loads than with TS, increasing TW and TUT while resulting in similar PP and %VL. Therefore, cluster-set structures may function as an alternative method to traditional strength- or hypertrophy-oriented training by increasing training load without increasing %VL or decreasing PP.

Research was conducted in the University Forest at Yagirala Forest Reserve, KalutaraDistrict, Sri Lanka, to compare the efficiency of point and plot sampling in Pinus caribaeaplantation using computer simulated sampling on a population of trees using data collectedin the field. In all, 3294 trees on 5.4 hectares constitute the population. The data base hasbeen filed with tree number, dbh, X and Y co-ordinates. Edge effect bias was minimizedusing the reflection method. Random sampling was used in all cases for sample sizes n = 10, 20, 30, 60 and 100. Inorder to make meaningful comparisons, the concept of equivalent plot was used whichaimed at obtaining equal tallies per sampling unit for point and plot sampling. Basal areafactors applied were 2, 4, 9 and 16. Efficiency for given point - plot equivalents werebased on standard error % and cost values (where cost was based on time). In 19 of the 20point-plot combinations studied, point sampling was found to be the more efficient. Themost suitable BAF is BAF2 and it is recommended that point sampling be applied inplantation forest inventories in Sri Lanka where trained staff are available.

Horizontal point sampling is only occasionally applied under natural tropical forest conditions. Reasons for this include those relating to the complex floristic composition and structure of these forests and to the presence of unacceptable non-sampling errors resulting from missing trees and incorrect borderline tree checking procedures. Concerning the latter, results from this study, based on probabilities and data derived from computer-simulated sampling on each of three 16 ha real tree stem maps (from Surinam, Kalimantan and Thailand), suggest that there is a statistically valid practical solution. Clusters of points using large basal area factors are used to concentrate work and to ensure that less effort is required in checking the ‘in/out’ status of a borderline tree. For a given basal area factor and bulk of sample, there is no significant difference between the various cluster point layouts used — this offering flexibility in execution.

The intriguing binary LS V +22 25 (LB-1) has drawn much attention following claims of it being a single-lined spectroscopic binary with a 79-day orbit comprising a B-type star and a ~70 Msun black hole. Recent analyses have implied that the visible primary star is a stripped He-rich star. However, the nature of the secondary, which was proposed to be a black hole, a neutron star, or a main sequence star, remains unknown. Based on 26 newly acquired spectroscopic observations, we perform an orbital analysis and spectral disentangling of LB-1 to elucidate the nature of the system. Our analysis reveals that LB-1 contains two components of comparable brightness in the optical. The narrow-lined primary, which we estimate to contribute ~55% in the optical, has spectral properties that suggest that it is a stripped star: it has a small spectroscopic mass (~1 Msun) for a B-type star and it is He- and N-rich. The "hidden" secondary, which contributes about 45% of the optical flux, is a rapidly rotating (vsini ~ 300 km/s) B3 V star with a decretion disk -- a Be star. Hence, LB-1 does not contain a compact object. Instead, it is a rare Be binary system consisting of a stripped star (the former mass donor) and a Be star rotating at near its critical velocity (the former mass accretor). This system is a clear example that binary interactions play a decisive role in the production of rapid stellar rotators and Be stars., Comment: Accepted to A&A. 4 pages (1 figure, 1 table); 3 pages of supporting material (7 figures and 1 table)