ObjectivesThe aims of the study were to establish normative full golf swing launch data for golfers with disabilities and to examine the relationships between Sport Class and swing performance.Methods142 competitive golfers (mean ± SD, age = 40.6 ± 14.1 years, 27 female, 115 male), across four disability Classes struck shots with three different clubs. Club and ball launch variables were measured using a Doppler-radar based launch monitor. Descriptive statistics and generalized linear models were used to establish normative data and within-class effects.ResultsThese novel normative data across seven key performance variables indicate a wide range of ball-striking ability and consistency both between and within classes. The Sitting playing style displayed lower carry distance [B = −60.9, SE = 7.3, p < 0.001, 95% CI (−75.2 −46.6), partial f2 = 0.17], higher carry distance variability [B = 2.4, SE = 1.0, p = 0.013, 95% CI (0.5 4.3), partial f2 = 0.01] and lower variability in offline distance [B = −2.9, SE = 0.7, p < 0.001, 95% CI (−4.4 −1.5), partial f2 = 0.04]. The visual playing style displayed higher carry distance variability [B = 2.6, SE = 0.8, p = 0.002, 95% CI (1.0 4.2), partial f2 = 0.02]. No other statistical performance differences were observed.ConclusionThe golfers displayed a wide range of ability in the key performance variables studied. Sitting golfers displayed significantly lower carry distance with all clubs compared to the other categories. These normative data will inform future research, governing bodies and tournament organizers.

It is accepted that highly skilled golfers are more consistent in their clubhead presentation and shot outcomes than their lesser skilled counterparts. However, the relationships between movement variability, outcome variability and skill in golf are not particularly well understood. This study examined the ground reaction force variability of one-hundred and four amateur golfers for shots with drivers and 5-irons. Principal component analysis was used as a data reduction technique and allowed all three components of ground reaction force to be considered together. There were statistically significant trends for the higher skilled golfers to display lower variability in two of the five principal components (driver) and four of the five principal components (5-iron). A similar trend was also observed in the other principal components, but these trends were not statistically significant. Intra-individual variability was much lower than inter-individual variability across all golfers; the golfers were each relatively consistent in maintaining their own ground reaction force patterns. Lower variability in ground reaction forces may partly explain how highly skilled golfers maintain lower variability in shot outcomes.

The relationships between movement style and golf performance have been well researched, but the premise of segregated movement styles has not been fully examined. The purpose of this investigation was to examine the postulation that centre of pressure data are not best described by segregated styles but instead by a continuum and to determine relationships between centre of pressure, handicap and clubhead speed using a continuous approach. Centre of pressure paths of driver and 5-iron shots from 104 amateur golfers were analysed using discrete and continuous methods. Discrete methods used different cluster evaluation criteria which result in two-cluster and twenty-cluster solutions being considered "optimum". The two-cluster solution showed the characteristics of "front-foot" and "reverse" centre of pressure styles. However, a continuous principal component analysis method revealed that the clusters were not well separated and provided support for a multidimensional continuum. The principal components had a high correlation with handicap and clubhead speed. Lower handicap and higher swing speed golfers tended to display a centre of pressure with a "front-foot" style and a fast transition towards the front foot at the start of the downswing. A continuous characterisation of centre of pressure styles has more utility than the segregated styles previously described.

Sports Medicine and Sports Biomechanics emerged as two viable branches of research interest in the late 1960s/early 1970s due to the growing interest in the scientific understanding of performance characteristics related to human motion. Today, there are somewhere in the region of 19 and 12 research journals that publish research findings in these respective areas. In this editorial, we reflect on the key role of the Journal of Sports Sciences in the dissemination of new sports medicine and sports biomechanics knowledge and provide guidelines to prospective authors who wish to submit their manuscripts to the Sports Medicine and Biomechanics section of the journal. Sports biomechanics research was central to the Journal of Sports Sciences at its inception in 1983 and has remained so over the intervening years. Sports biomechanics has been described as '‘having two aims that, at times, seem incompatible: the reduction of injury risk and the improvement of sports performance’ (Bartlett & Bussey, 2012, p.xix). The growing number of sports and exercise medicine research submissions to the journal in 2013 prompted Professor Alan Nevill, then Editor-in-Chief, to propose a separate Sports Medicine section. Consequently, Sports Medicine became the latest addition as one of twelve separate sections comprising the journal’s editorial structure that remained in place until 2017. Professor Mark Williams, in his editorial as the recently appointed Editor-in-Chief, reflected on the rapid growth and international reputation of the journal and the resultant huge increase in the number of submissions received by the journal (Williams, 2017). To better manage the workload of the editors, whilst providing tiered levels of quality control within each section and across the journal, a decision was made to restructure the Editorial Board. The synergies between Sports Medicine and Sports Biomechanics led to the combining of these two sections to form the current Sports Medicine and Biomechanics section. Other more recent developments to assist the editorial teams and to secure more robust research outcomes include the recommendation that submissions of experimental studies include a formal a priori sample size estimation and rationale (Abt et al., 2020), and the formation in 2020 of the journal’s Statistics and Research Design Advisory Group, led by Professor Grant Abt. The reach and reputation of the Journal of Sports Sciences is further evidenced by the 80 applications that were received in 2017 from researchers across the world for the Sports Medicine and Biomechanics Associate Editor positions. The section now has a core structure of an executive editor (Eric Wallace, Ulster University), four associate editors (Tim Exell, University of Portsmouth; Natalie Vanicek, University of Hull; Mark Robinson, Liverpool John Moores University – who in 2020 replaced Silvia Fantozzi, University of Bologna; and Massimiliano Ditroilo, University College Dublin, who was appointed in late 2020). Our editorial team is supported by the diverse expertise of our Sports Medicine and Biomechanics Advisory Board, who collectively provide a diversity of expertise. In 2017, our Advisory Board was refreshed with the addition of 12 new members giving a total of 30 advisors. A further streamlining revision in 2021, aimed also at increasing the diversity of our editorial teams (as outlined in the Journal’s editorial ‘Equality, Diversity and Inclusion: Policy Statement’, Abt et al., 2021a), resulted in an Advisory Board of 18 members with a welcome increase from 2% to 33% in female representation. We are deeply indebted to the invaluable contributions of our Advisory Board which, along with the countless critically reflective reviews by our voluntary reviewers, make a huge contribution to the continued publication of highquality research in Sports Medicine and Biomechanics. A recurring theme in the recent editorials has been the challenge imposed by the huge volume of submissions associated with the ongoing growth and reach of the Journal of Sports Sciences. The journal is ranked 13th out of 85 journals under Sports Science based on the total number of citations. Journal article downloads have increased by over 50% over the past 2 years and, in 2020, they surpassed one million for the first time. Alongside downloads through traditional databases, Twitter downloads almost doubled to 18,500 in 2020 and @JSportsSci now has over 45,000 followers. Of direct relevance to the Sports Medicine and Biomechanics section, the number of submissions has risen steadily over the last decade and now stands at over 500 per annum, . Citations, across a wide range of performance, sports medicine and technology papers, account for 20% of the top 100 cited journal papers for the period between 2017 and 2021. Inevitably, many submissions do not make it through to an external review for a range of reasons – including relevance to the scope of the section; lack of originality, rigour, and/or impact; being of limited interest to the journal’s wider readership; and the avoidance of over-saturation of specific topics or manuscript types, for example, systematic reviews. Authors wishing to submit their research manuscripts to the Sports Medicine and Biomechanics section should first consult the Instruction for Authors on the Journal of Sports Sciences’ website. We would strongly encourage authors to consider the submission option of Registered Reports, which is designed to promote research transparency and help combat issues of publication bias, along with questionable practices such as p-hacking. For a full consideration of the issues, and how Registered Reports attempt to address them, we encourage you to read the recent Journal of Sports Sciences ‘Registered Reports’ editorial by Abt et al. (2021b). The aims and focus of the manuscript’s research must be clearly associated with one, or both, of the following two research areas: sport and exercise medicine and sport and exercise biomechanics. We specifically welcome studies with perceived high impact related to injury and JOURNAL OF SPORTS SCIENCES 2022, VOL. 40, NO. 8, 838–839 https://doi.org/10.1080/02640414.2022.2040885

In golf, it is well understood that the interaction between the clubhead and ball determines the initial ball launch conditions. Specific knowledge regarding these relationships for iron clubs, particularly when clubhead and turf interactions are considered, would be both novel and of benefit to practitioners. Linear regression analysis was used to determine relationships between selected clubhead presentation and shot outcome variables for a sample of 1127 '5-iron' shots hit from natural turf by 96 golfers. As expected, clubhead speed was the most significant predictor of ball speed, with obliquity of impact and eccentricity of the impact location making smaller, yet statistically significant contributions. Marginally 'fat' strikes, whereby the leading edge of the clubhead was only slightly beneath the ground at impact, appeared to have a lesser effect than expected in terms of ball speed. Effective loft was found to be the strongest predictor of vertical launch angle, whilst clubhead speed and spin loft had the greatest influence in the model for predicting total spin; inclusion of 'thin' strikes (i.e. those struck with the leading edge) appeared to create a non-linear element to these models and consequently overestimated the influence of vertical impact location in both cases. These findings suggest that determination of impact location, particularly for instances whereby ball contact is not wholly on the club face, is critical in research concerning irons. Overall, this study makes an original contribution to the understanding of 5-iron shot outcomes based on clubhead presentation characteristics.

We published a recent editorial on sample size estimation (Abt et al., 2020), which was one in a series of editorials over many years intended to encourage authors to improve the rigour of studies submitted to the Journal of Sports Sciences (Nevill et al., 2004; Winter et al., 2014). We continue this encouragement now with the introduction of the Registered Report submission format. As highlighted in our editorial (Abt et al., 2020), and by many others (Caldwell et al., 2020; Ioannidis et al., 2014; Munafò et al., 2017), there are a number of problems that plague modern science; publication bias, questionable research practices, and underpowered studies to name but a few. Jones and Brewer (1972) reported that for studies published in Research Quarterly (now Research Quarterly for Exercise and Sport) the calculated power for different effect sizes was “disturbingly low” – 0.15, 0.54, and 0.83 for small, medium, and large effect sizes, respectively. These findings have been largely confirmed by similar studies in 1977, 2000, and 2020 that explored the same issues across numerous journals (Christensen & Christensen, 1977; Kinney et al., 2020; Speed & Andersen, 2000). Collectively, these studies suggest that the power of a typical study published in our discipline has a high probability of detecting a large effect, a medium probability of detecting a medium effect, and a very low probability of detecting a small effect. As noted by Speed and Andersen (2000), small effects in the sport sciences are often associated with the difference between winning and losing. As such, it is potentially important to be able to detect important effects, however small. Yet, underpowered studies are just one problem that sport and exercise scientists need to deal with. Questionable research practices and publication bias have been reported across a range of scientific disciplines (Ioannidis et al., 2014), and we are not immune (Caldwell et al., 2020). So, what are the solutions? A number of recommendations have been made over the last decade to improve the rigour of research and to minimise the introduction of these problems into the literature (Caldwell et al., 2020; Munafò et al., 2017). Two of these are the use of preregistration and the Registered Report submission format. Preregistration allows reviewers, editors, and readers to transparently evaluate the capacity of a test to falsify a prediction (Lakens, 2019). Preregistration (ideally a priori) involves publishing a timestamped protocol that outlines all data collection procedures together with a data analysis plan (Nosek et al., 2018). The data analysis plan usually involves identifying what are termed “confirmatory” and “exploratory” analyses (Caldwell et al., 2020). Publishing the data collection and analysis protocols prior to data collection allows authors to minimise the temptation to engage in questionable research practices (e.g., p-hacking, HARKing). Preregistration encourages greater transparency and rigorous reporting of study methods and analyses (Toth et al., 2020). Although we strongly support the use of preregistration, it is still open to abuse and manipulation (Ikeda et al., 2019; Yamada, 2018). The Registered Report format takes preregistration one step further by formalising the registration process and allowing reviewer feedback prior to data collection. Unlike the traditional peer-review process, which involves peer-review after data collection, the Registered Report format involves peer-review both before and after data collection (Chambers, 2013; Impellizzeri et al., 2019). This two-stage process not only has the benefits of preregistration but also allows authors to receive feedback on the proposed methods and data analysis before data collection, when they have the ability to modify these features. With a post-data peer-review process it is too late to make changes to the method, refine the research question, and/or hypotheses. Moreover, the Registered Report format has the potential to reduce publication bias by allowing editors to gauge the value of a study without being biased by the results. In an exploratory analysis, Allen and Mehler (2019) reported that the number of null findings increased from ~5-20% with traditional peer-review to ~60% with the Registered Report format. In a similar vein, Scheel et al. (2021) reported that positive findings reduced from 96% in the standard literature to 44% in Registered Reports. Although the Open Science Framework lists over 260 journals that offer the Registered Report format (Open Science Framework, n.d.), only a few of these are in the sport and exercise sciences, namely, Human Movement Science (Dessing & Beek, 2015), Science and Medicine in Football (Impellizzeri et al., 2019), Psychology of Sport and Exercise, and Registered Reports in Kinesiology. Like the other journals in our field that have implemented the Registered Report format, we encourage authors to embrace the methods of open science to improve the quality of their research. We hope authors will engage with this new submission type and we look forward to helping them through the two-stage process. Improving research practices is everyone’s responsibility – authors, journals, editors, and reviewers. At the Journal of Sports Sciences, we want to play our part in enabling researchers to do their best work, and we believe that the Registered Report format is a positive step towards that goal.

The Editor-in-Chief and Executive Editors of the Journal of Sports Sciences all identify as male and white. Although the journal’s Associate Editors and the Editorial Advisory Board are more diverse, it is cold comfort that the Journal of Sports Sciences is not alone in having very few senior editors who identify as female or people of colour (Martínez-Rosales et al., 2021). The lack of diversity in gender and ethnicity on editorial boards has been an issue for a long time across many fields of study (Alkhawtani et al., 2021; Metz & Harzing, 2009, 2012; Van Miegroet et al., 2019) and the historic underrepresentation of women in public office (Uberoi et al., 2021) and company boardrooms (Davies, 2011) has not evaded academia. Yet, it is argued that the relationship between women and leadership is not simply one of under-representation, but of male dominance (patriarchy), with sport one of the key domains for the confirmation of masculinity (Messner, 2007; Ryan & Dickson, 2018). Although we do not have data on editorial board ethnicity for our field of science, it is likely that people of colour are equally, if not more, under-represented at this level (Ford et al., 2017). Although the under-representation of women is clearly a multifactorial problem (Hardcastle et al., 2019), we can start to understand how the problem may develop in sport and exercise science by examining the gender diversity of students entering academic programmes across countries and continents. In the UK, for example, where the Journal of Sports Sciences is published, 48.7% of the adult population report to be female (Office for National Statistics, 2020), whereas the UK Higher Education Statistics Agency reports that 32% of those studying undergraduate sport and exercise science in the 2019/ 20 academic year were female (13,840 ♀ vs 28,885 ♂) (Higher Education Statistics Agency, n.d.-b). The gender imbalance in sport and exercise science contrasts with that observed across all higher education courses in the UK, where 57% of students are female (1.4 M ♀ vs 1.1 M ♂) (Higher Education Statistics Agency, n.d.-b). Moreover, the imbalance doesn’t appear to have shifted much over time, with females accounting for 29% of undergraduate sport and exercise science students in the 2014/15 academic year (13,875 ♀ vs 33,325 ♂) (Higher Education Statistics Agency, n.d.-c). The number of females doing a postgraduate research or taught degree in sport and exercise science in 2019/20 was 1755, representing 33% of all postgraduate sport and exercise science students (Higher Education Statistics Agency, n.d.-b) (1755 ♀ vs 3560 ♂). So, the figures do not differ markedly relative to the proportion studying at undergraduate level. As far as academic staff working in sport and exercise science departments, in the UK, 37% are female (1125 ♀vs 1915 ♂) (Higher Education Statistics Agency, n.d.-d). In contrast, the number of female academics across all fields of higher education in the UK in 2019/20 was 104,305, representing 47% of all faculty, which is very close to the proportion of female adults in the UK (Higher Education Statistics Agency, n.d.-e). However, the percentage of female academics at “senior” level drops to 39%, and then further to 28% at professorial level. Collectively, these data suggest two things: (1) the gender imbalance in sport and exercise science is evident in undergraduate sport and exercise science programmes; and (2) this imbalance creates a smaller cohort of potential female sport and exercise science academics, particularly at senior level from whom editorial positions are normally filled. Unfortunately, data on ethnicity are not as accessible as those for gender. It is therefore difficult to quantify if sport and exercise science journals and/or student cohorts lack ethnic diversity. Data across all fields of higher education show that about 25% of students are people of colour (Higher Education Statistics Agency, n.d.-a), yet fewer than 1% of professors are Black (Higher Education Statistics Agency, n.d.-e), the latter constituting a lower proportion of Black academic staff (3.5%) compared to white professors as a proportion of white academic staff (11.9%) (Joice & Tetlow, 2020). It is therefore highly likely that people of colour are under-represented on editorial boards (Ford et al., 2017). Moreover, the interaction of gender and ethnicity (Ryan & Dickson, 2018) creates an even greater barrier for women of colour. Although women and people of colour are underrepresented at the higher levels of academia and on editorial boards, why does this matter? There are two main reasons. First, although contested, it is a moral issue (Köllen et al., 2018). Second, and as outlined by Fine et al. (2020) in relation to gender diversity, ensuring equal access to leadership positions “makes an important contribution to reducing the broader political, sociocultural, and material disadvantages women face, in part by giving women greater influence in high-level decision-making”. Although an argument for gender and/or ethnic diversity on sociocultural grounds

Iron clubheads can be classified as blades or perimeter-weighted, depending on the distribution of their mass. Despite the widely held views that perimeter-weighting can offer performance benefits for lesser skilled players, a direct comparison with players using these two clubhead types has not been thoroughly investigated. The aims of the study were to determine differences in clubhead presentation and ball launch between a blade 5-iron and a cavity-back 5-iron in a mixed cohort of golfers and examine trends in central tendency and variability in relation to skill for males using the blade club. Nine clubhead presentation variables and six ball launch variables were measured for 96 participants hitting shots from natural turf with each of the clubs. Group means for club effect were analysed statistically using an independent samples approach, whilst a rank-based nonparametric test was used to determine significant trends between handicap categories and ball launch conditions for the male cohort. The cavity-back displayed higher effective loft, lower effective lie and a tendency to have ball strikes closer to the centre. Higher values were also noted for the cavity-back for vertical launch angle and total spin. As expected, higher handicap male golfers showed lesser consistency and displayed slower ball speeds and lower efficiency than the more skilled players. Together these results concur with the findings in Part I in support of the theory of ‘forgiveness’ associated with cavity-back clubs, whilst also highlighting the over-riding importance of skill level on performance.

The majority of papers submitted to the Journal of Sports Sciences are experimental. The data are collected from a sample of the population and then used to test hypotheses and/or make inferences a...

Isometric tests have been used to assess rate of force development (RFD), however variation in testing methodologies are known to affect performance outcomes. The aim of this study was to assess the RFD in the isometric squat (ISqT) using two test protocols and two testing angles. Eleven participants (age: 26.8 +/- 4.5years, strength training experience: 7.1 +/- 3.03years) completed test and retest sessions one week apart, whereby two test protocols with respect to duration and instructions were compared. Isometric peak force (ISqT(peak)) and isometric explosive force (ISqT(exp)) tests were assessed at two joint angles (knee flexion angle 100 degrees and 125 degrees). Force-time traces were sampled and subsequently analysed for RFD measures. Average and instantaneous RFD variables did not meet reliability minimum criteria in ISqT(peak) at 100 degrees or 125 degrees. The ISqT(exp) test at 100 degrees met reliability criteria in the RFD 0-200 and 0-250ms variables. The ISqT(exp) test at 125 degrees met reliability criteria in the RFD 0-150, 0-200 and 0-250ms variables. Force-time characteristics were optimized at the higher knee joint angle. Average and instantaneous RFD measures obtained using a traditional peak force test do not meet basic reliability criteria. Researchers assessing multi-joint RFD should employ the explosive RFD test protocol as opposed to the traditional isometric peak force protocol.

There is much debate around the role of shaft stiffness in the dynamic response of the club shaft during the golf swing. This study used a novel complex analysis to investigate within- and between-golfer differences in shaft strain patterns for three shaft stiffnesses. Twelve right-handed male golfers, with a handicap less than or equal to five, hit six shots with three driver clubs which differed only in shaft stiffness. Clubs were instrumented to record the shaft strain in the lead/lag and toe/heel directions. The analysis combined these perpendicular components into a single complex function, which enabled the differences between two swings to be characterised by a scale and a rotation component. Within-golfer strain patterns were found to be significantly more consistent than between-golfer, p < 0.01. Whilst some golfers displayed more similar patterns than others, there were no clear groups of golfers with similar patterns of shaft strain. Between the clubs, shaft strain patterns differed in the scale component, p < 0.01, rather than the rotation, p = 0.07.

This study aimed to evaluate responsiveness (ability to detect change) of isometric force-time measures to neuromuscular fatigue in resistance-trained participants using two differing protocols that modified both the instructions provided to participants and the duration of the test. Both protocols were completed at two knee joint angles in the isometric squat test. Ten participants volunteered to take part in this study (age: 27.0 +/- 4.5 years, strength training experience: 7.7 +/- 2.6 years). Isometric peak force (ISqT(peak)) and isometric explosive force (ISqT(exp)) test protocols were assessed at two joint angles (knee angle 100 degrees and 125 degrees) pre-high intensity strength training, immediately post strength training, 24-h post, 48-h post and analysed for peak and RFD performance. Participants completed eight sets of three repetitions of the back-squat exercise as the high-intensity strength training. Results showed the highest standardised response means (SRM) detected was peak force using the ISqT(peak) 100, SRM -1.97 compared to an SRM of -1.31 for RFD 200 ms in the ISqT(exp) 125. Peak force was the most responsive variable using the ISqT(peak) protocol, whereas the ISqT(exp) protocol was most responsive for RFD measures. Therefore, ISqT(peak) and ISqT(exp) test protocols should not be used interchangeably to evaluate RFD variables.

The study presents a novel application of measures of the structure of variability to ground reaction force trajectories and highlights the use of such measures to provide valuable information about coordination of the golf swing. The variability and regularity of ground reaction force trajectories were quantified for iron and driver shots from three participants with different skill levels. Pointwise median absolute deviation was used to indicate the variability of ground reaction force trajectories across their length, and two alternative methodologies, sample entropy and cross-sample entropy, were used to determine their regularity. For both driver and iron shots, results showed that while there was no difference in the magnitude of variability between any of the participants, there were differences in the structure of this variability. In general, the ground reaction force of the highest skilled participant was significantly more regular than that of the lesser skilled golfers. However, differences occurred across the various components of ground reaction force. Thus, entropy measures can provide additional valuable information concerning dissimilarities among golfers of various skill levels and may indicate differences in neuromuscular system coordination during the golf swing. This study highlights the importance of considering the structure of variability, as well as its magnitude, and describes methods which could be applied to further investigations.

The importance of iron play to scoring in golf is widely recognised. To better understand this relationship, accurate, yet unobtrusive measurement techniques are required to capture information about the collision between the golf club and ball. This article presents a method for tracking an iron clubhead prior to impact with the ball. Using repeated shots by a golf robot with a 5-iron and 9-iron, the system reliably measured clubhead speed (standard deviation ≤ 0.5 mile/h), face angle (≤0.2°), club path (≤0.2°), effective loft (≤0.5°), attack angle (≤0.1°) and effective lie (≤0.3°). Impact position was within a standard deviation ≤ 0.6 mm for repeated shots. Absolute accuracy of horizontal impact position at initial contact was <1 mm, whereas a systematic offset of up to 4 mm was found for vertical impact position compared to tests using impact location tape. This offset was dependent on the loft of the club and could be explained by the interaction between ball and club during contact. In addition, a unique feature of the algorithm is presented which categorises impacts commonly known as ‘top’, ‘thin’, ‘good’ or ‘heavy’ shots, which is facilitated through tracking of the bottom edge of the clubhead using virtual markers. Hence, this tracking system is presented as a novel solution to accurately measure clubhead presentation and initial ball impact location for irons.

Isometric multi-joint tests are considered reliable and have strong relationships with 1RM performance. However, limited evidence is available for the isometric squat in terms of effects of familiarization and reliability. This study aimed to assess, the effect of familiarization, stability reliability, determine the smallest detectible difference, and the correlation of the isometric squat test with 1RM squat performance. Thirty-six strength-trained participants volunteered to take part in this study. Following three familiarization sessions, test-retest reliability was evaluated with a 48-hour window between each time point. Isometric squat peak, net and relative force were assessed. Results showed three familiarizations were required, isometric squat had a high level of stability reliability and smallest detectible difference of 11% for peak and relative force. Isometric strength at a knee angle of ninety degrees had a strong significant relationship with 1RM squat performance. In conclusion, the isometric squat is a valid test to assess multi-joint strength and can discriminate between strong and weak 1RM squat performance. Changes greater than 11% in peak and relative isometric squat performance should be considered as meaningful in participants who are familiar with the test.

Since the times and works of William Sealy Gosset (1876–1937) and Ronald Aylmer Fisher (1890–1962), imperfections of conventional null-hypothesis significance testing and in particular, use of P-values to evaluate such testing (invariably referred to as inferential statistics), have been well recognised (Wasserstein & Lazar, 2016; Wilkinson, 1999). Attempts have been made to identify alternatives. For example, Cohen’s effect sizes (Cohen, 1988) and region of practical equivalence procedure (ROPE) (Kruschke, 2014). A more recent alternative is magnitude-based inference (MBI) (Hopkins & Batterham, 2016) although unlike others, MBI has created considerable controversy when reporting the results of studies (almost exclusively used in the field of sport and exercise science). Instead of defining research effects as “significant” based on P-values (using traditional hypothesis testing), MBI uses terms such as “implementable” and “substantial” based on two constraints called the “risk of harm” and the “chance of benefit”. However, concerns have been raised about the MBI approach. Stanford statistician Kristin Sainani was so concerned about the consequences of using MBI that she wrote a formal analysis of the MBI method. Published in MSSE (Sainani, 2018) her paper showed that, depending on sample size and thresholds for harm/benefit, MBI produces false positive rates that can be two to six times greater than those using traditional hypothesis testing. A finding, she claims, that makes MBI less reliable. Loosening or lowering the standard of evidence (increasing the false positive rates) has important consequences. Of course, we recognise the reciprocal nature of error reduction i.e., by increasing Type I error rates (false-positives), we automatically reduce Type II (false-negative) rates and vice versa. Ethically, declaring that many interventions work when they do not, is unacceptable to editors and practitioners alike. For example, an athlete could adopt several interventions, many of which might not work. This is wasteful in time, cost and energy. Sainani provided several examples, including those from published papers, where MBI indicated either implementable or substantial interventions that were not statistically significant. As such, Medicine and Science in Sport and Exercise (MSSE) has decided not to accept for publication papers that use MBI. After consultation with the journal’s Editorial Board, the Editor in Chief (Bruce Gladden) has decided not to allow MBI until a properly vetted account of the method has been published in a recognized statistics journal (and he recommended that researchers should not use MBI until that occurs). There is another concern with MBI and traditional hypothesis testing used in sport and exercise research. All MBI, and the majority of traditional hypothesis-testing inferences, are based on confidence intervals that assume data are symmetric and normally distributed (e.g., all confidence intervals used in MBI are calculated using an appropriate t-value, say at the 95% probability, multiplied by the standard error of the mean). The majority of data reported in sport and exercise science are measured on the ratio rather than the interval scale (e.g., maximum oxygen uptake, strength and speed). Because ratio data cannot be negative (such data are bounded to the left by zero but invariably unbounded to the right), ratio data tend to be positively skewed and, as such, will not be symmetric (i.e., using symmetric confidence intervals is likely to be misleading). This positive skew characteristic in such ratio data can be overcome by taking logarithms (see Nevill, 1997). Neither supporters of MBI nor its opponents, including Sainani (2018), appear to be concerned about whether the data they are considering are, or are not, symmetric and satisfy normaldistribution assumptions, assumptions that need to be assumed when deciding whether or not an effect is likely to be real. In 2014, the Journal of Sports Sciences (Winter, Abt, & Nevill, 2014) outlined its revised policy on how to report statistical inference. Manuscripts would not be accepted for publication if analyses were evaluated solely based on P-values. Authors were encouraged to provide supplementary statistics such as effect sizes and confidence intervals (usually the 90% or 95%) that would provide readers with additional information to assess the benefit of an intervention. This policy reflects a cautious approach that erred on the side of evolution rather than revolution (i.e., P-values were not barred completely and specific alternatives were not stated as preferences). The debate as to whether MBI is a suitable alternative to P-values is likely to continue for some time. However, following the Journal’s traditionally conservative approach, the Editorial Board is unanimous in its view that until MBI receives formal endorsement from academic and medical statisticians alike (e.g., an endorsement published in reputable journals such as the Royal Statistical Society and the BMJ respectively), MBI should be used with caution. When choosing which methods of inference to report, we prefer authors to adopt the recommendations outlined in the editorial written by Winter et al. (2014).

Although the swing plane has been a popular area of golf biomechanics research, the movement of the club relative to the swing plane has yet to be shown experimentally to have a relationship with performance. This study used principal component and subsequent multiple regression analysis to investigate the relationship between the movement of the club relative to the delivery plane and clubhead characteristics at ball impact. The principal components reflected deviations from an individual swing plane, and lower values of these components were associated with less variability in the clubface impact location. In the event that a golf coach wants to improve the precision of ball striking, the results from this study suggest that both simplicity of the route and alignment of the club to the final trajectory before impact could be advantageous. However, this does not suggest that the technique should be based on a 'model' swing plane.

Research and equipment testing with golf robots offers much greater control and manipulation of experimental variables compared to tests using human golfers. However, whilst it is acknowledged that the club gripping mechanism of a robot is dissimilar to that of a human, there appears to be no scientific findings on the effects of these gripping differences on the clubhead at ball impact. Theoretical and experimental strain propagation rates from the clubhead to the grip and back to the clubhead were determined during robot testing with a 9-iron to determine if this time interval was sufficiently short to permit the gripping mechanism to have an effect on the clubhead during impact. Longitudinal strain appears to propagate the most quickly, but such deflections are likely to be small and therefore of little meaningful consequence. Shaft bending was not a primary concern as modes of large enough amplitude appear to propagate too slowly to be relevant. Torsional strain propagates at a rate which suggests that constraints at the grip end of a golf club could potentially influence impact dynamics for steel shafted irons; however, this effect seems unlikely to be significant, a likelihood that decreases further for longer irons. As such, it is considered reasonable to treat the influence of a robot’s gripping mechanism on clubhead dynamics at impact as negligible, and therefore comparisons between robot and human data in this regard are valid.

BACKGROUND:The aims of the study were to investigate the number of familiarization sessions required to establish reliability of the bounce drop jump (BDJ) and subsequent reliability once familiarization is achieved.METHODS:Seventeen trained male athletes completed 4 BDJs in 4 separate testing sessions. Force-time data from a 20 cm BDJ was obtained using two force plates (ensuring ground contact <250 ms). Subjects were instructed to "jump for maximal height and minimal contact time" while the best and average of four jumps were compared. A series of performance variables were assessed in both eccentric and concentric phases including jump height, contact time, flight time, Reactive Strength Index (RSI), peak power, rate of force development (RFD) and actual dropping height (ADH). Reliability was assessed using the intraclass correlation coefficient (ICC) and coefficient of variation (CV) while familiarization was assessed using a repeated-measures analysis of variance (ANOVA).RESULTS:The majority of DJ parameters exhibited excellent reliability with no systematic bias evident, while the average of 4 trials provided greater reliability. With the exception of vertical stiffness (CV: 12.0%) and RFD (CV: 16.2%), all variables demonstrated low within subject variation (CV range: 3.1-8.9%). Relative reliability was very poor for ADH, with heights ranging from 14.87-29.85 cm.CONCLUSIONS:High levels of reliability can be obtained from the BDJ with the exception of vertical stiffness and RFD, however, extreme caution must be taken when comparing DJ results between individuals and squads due to large discrepancies between actual drop height and platform height.

Background: Researchers and practitioners working in sports medicine and science require valid tests to determine the effectiveness of interventions and enhance understanding of mechanisms underpinning adaptation. Such decision making is influenced by the supportive evidence describing the validity of tests within current research. The objective of this study is to review the validity of lower body isometric multi-joint tests ability to assess muscular strength and determine the current level of supporting evidence.Methods: Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed in a systematic fashion to search, assess and synthesize existing literature on this topic. Electronic databases such as Web of Science, CINAHL and PubMed were searched up to 18 March 2015. Potential inclusions were screened against eligibility criteria relating to types of test, measurement instrument, properties of validity assessed and population group and were required to be published in English. The Consensus-based Standards for the Selection of health Measurement Instruments (COSMIN) checklist was used to assess methodological quality and measurement property rating of included studies. Studies rated as fair or better in methodological quality were included in the best evidence synthesis.Results: Fifty-nine studies met the eligibility criteria for quality appraisal. The ten studies that rated fair or better in methodological quality were included in the best evidence synthesis. The most frequently investigated lower body isometric multi-joint tests for validity were the isometric mid-thigh pull and isometric squat. The validity of each of these tests was strong in terms of reliability and construct validity. The evidence for responsiveness of tests was found to be moderate for the isometric squat test and unknown for the isometric mid-thigh pull. No tests using the isometric leg press met the criteria for inclusion in the best evidence synthesis.Conclusions: Researchers and practitioners can use the isometric squat and isometric mid-thigh pull with confidence in terms of reliability and construct validity. Further work to investigate other validity components such as criterion validity, smallest detectable change and responsiveness to resistance exercise interventions may be beneficial to the current level of evidence.