Unforced Errors Research Articles

The impact of sleep behaviours, chronotype and time of match on the internal and external outcomes of a tennis match

Tennis match performance is often evaluated by a player's internal (heart rate) and external (match analytics) outcomes. Numerous factors could influence these outcomes, including the time of day, which may be advantageous or not depending on a player's chronotype. This study aimed to determine the influence time of day, chronotype and sleep–wake behaviour (SWB) had on internal and external outcomes of tennis matches. Twelve state-level male tennis players, with a mean age of 28 ± 7, stature of 183 ± 7 and body mass of 86.6 ± 17.4 wore an actigraph device and completed a sleep diary for the study duration. Based on rankings, players were paired against the same opponent and completed three tennis matches at 8:00 am, 2:00 pm and 8:00 pm, separated by a minimum of 48 h. Fatigue and chronotype, measured by the Fatigue Severity Scale, Morningness Eveningness Questionnaire and midsleep time, were assessed before matches; motivation, measured by the Intrinsic Motivation Inventory, was assessed after matches. During matches, players wore global positioning systems and heart rate monitors; the match analytics and players’ rate of perceived exertion were recorded. Increased unforced errors and decreased winners and forced errors were observed in the evening matches. Decreased total distance and rate of perceived exertion during the second set were found for the evening compared to morning and afternoon matches. Chronotype and sleep–wake behaviour had trivial to weak associations with internal and external outcomes. These results indicate that players and coaches should consider the match times when training for future tournaments.

Is autologous platelet activation the key step in ovarian therapy for fertility recovery and menopause reversal?

Platelets are a uniquely mammalian physiologic feature. As the only non-marine vertebrates to experience menopause, humans have a substantial post-reproductive lifespan and are believed to have a limited, non-renewable oocyte supply. Ovarian reserve typically declines after about age 35yrs, marking losses which cannot be recovered by available fertility medications. When in vitro fertilization fails due to low or absent ovarian response, gonadotropin adjustments are often ineffectual and if additional oocytes are occasionally harvested, egg quality is usually poor. This problem was confronted by Greek researchers who developed a new surgical method to insert autologous platelet-rich plasma (PRP) into ovaries; the first ovarian PRP success to improve reproductive outcomes was published from Athens in 2016. This innovation influenced later research with condensed platelet-derived growth factors, leading to correction of oocyte ploidy error, normal blastocyst development, and additional term livebirths. Yet women's health was among the last clinical domains to explore PRP, and its role in 'ovarian rejuvenation' remains unsettled. One critical aspect in this procedure is platelet activation, a commonly overlooked step in the cytokine release cascade considered essential for successful transition of undifferentiated ovarian stem cells to an oocyte lineage. Poor activation of platelets thus becomes an unforced error, potentially diminishing or even negating post-treatment ovarian follicular response. To answer this query, relevant theory, current disagreements, and new data on platelet activation are presented, along with clinical challenges for regenerative fertility practice.

Influence of scaling on match play characteristics in youth tennis: A systematic review

Scaled tennis is the downsized version of adult tennis and aims to allow youth players to play a type of tennis that resembles adult tennis. However, since the different scaling conditions (red, orange, lime and green tennis court) were chosen pragmatically it is unclear whether the match play characteristics of scaled tennis resemble those of adult tennis. It is also unclear whether the match play characteristics are comparable between the different scaling conditions (allowing a smooth transition through the scaled courts). Therefore, this systematic review aims to compare match play characteristics in scaled tennis to adult tennis, and to compare match play characteristics across the different scaling conditions. The PubMed, Web of Science and SPORTDiscus (EBSCO) databases were searched until November 2021. The match play characteristics included first serve percentage, percentage of first serve points won, percentage of second serve points won, percentage of total serve points won, number of aces, number of double faults, winners’ percentage, unforced errors percentage, percentage of break points won, rally duration and inter contact time. The systematic search identified 887 records and six studies were included. All included match play characteristics, apart from the percentage of second serve points won and a number of double faults, showed significant differences between scaled tennis and adult tennis. Similarly, all included match play characteristics, except for a number of double faults, showed significant differences between the different scaling conditions. Based on these results, future research is needed to optimise the different scaling conditions in terms of match play characteristics.

Electro-prosthetic E-skin Successfully Delivers Finger Aperture Distance by Electro-Prosthetic Proprioception (EPP).

Electronic skin (E-skin) is an emerging wearable device typically used to mimic the function of the human skin, mainly by replicating the role of tactile sensory receptors in the skin. This study showed an interesting modification of the E-skin, called an electro-prosthetic E-skin, which adds the functionality of distance sensing and stimulation of the palmar digital nerve. The electro-prosthetic E-skin operates as a closed loop to deliver the finger aperture distance information to the nervous system. This E-skin was implemented as an additional layer mounted to the original human skin, to be worn on the fingertip with a thin silicone substrate. The E-skin was designed to be mounted onto the index fingertip, to deliver the distance information between the fingertips and to enhance the finger aperture distance control. In this study, we demonstrated that electro-prosthetic proprioception (EPP), implemented with the electro-prosthetic E-skin, successfully delivered the distance information between the fingertips and enhanced the finger aperture distance control accuracy. Clinical Relevance- Presented electro-prosthetic E-skin delivering finger aperture distance via electro-prosthetic proprioception (EPP) will enhance accuracy of the finger aperture distance control. This technology can be applied to the neurosurgery to minimize unforced errors caused by the limited human control accuracy over the fingertip.

Padel Match Analysis: Notational and Time-Motion Analysis during Official Italian Sub-Elite Competitions.

Although performance analysis in padel represents a useful process to gain references about players’ technical and tactical behavior, most of the research was conducted in elite compared to the sub-elite competitions. Therefore, this study aimed to describe sub-elite competitions in order to enhance scientific knowledge for sub-elite athletes and technical staff. 4287 shots were analyzed within five areas (time-motion analysis, shots characteristics, errors, serve and points won). Effective playing time and work-to-rest ratio were lower than in elite competitions, while strokes per minute and total match duration were in line with it. Shots were mainly forehand volleys performed under the head, while volleys and smashes were more likely to end with a point in comparison with ground or wall shots. However, sub-elite winning pairs performed fewer volleys than the losing side and fewer errors on volleys. One serve out of five ended in errors (almost half were net errors); fewer errors during serve return shots represented an advantage for the winning pairs. Finally, 65% of the points scored were caused by unforced errors of opponents. This knowledge should help technical staff design specific training programs for sub-elite padel players.

Comparison of the game structure and point ending during Grand Slam women's doubles tennis

Despite the importance of doubles tennis, there is little research on this modality of the game, especially as per women play. The aim of this study was to analyse the structural variables and the way points ended in women's doubles, as well as to observe the differences between surfaces and between winning and losing teams. Twenty-one WTA doubles matches from three Grand Slams played on three different surfaces were analysed. Players played 2.0 ± 0.3 sets, 19.9 ± 3.2 games, 130.4 ± 25.3 points, 0.2 ± 0.6 tie breaks per match (PM), 9.5 ± 1.0 games and 62.6 ± 7.9 points per set, and 6.6 ± 0.6 points per game (PG). 33.5% of the points ended with a winner (Wn), 43.6% with a forced error (FE) and 22.8% with an unforced error (UE), with the Wn shot being the variable that most discriminated between winner and loser teams. It was also shown that the way more points were finished was with FE, followed by Wn and UE. There were no significant differences between surfaces in structural variables or point ending. These results showed that in women's doubles playing Wn shots and avoiding UE is crucial to successful performance, so that aggressive play and taking the initiative in the game has a positive influence in the result.

ВЪЗДЕЙСТВИЕ НА ПРИЛОЖЕНА ПРОГРАМА ВЪРХУ ,,СИГУРНОСТТА“ НА УДАРИТЕ ПРИ СЪСТЕЗАТЕЛКИ ПО БАДМИНТОН

The data presented in this study define the quantitative evaluation of the indicator „security” in the playing technique for the discipline „Women-single”. The forced and unforced errors made by 5 Bulgarian badminton players during matches of state championships were determined. The data were recorded for 15 game indicators (strokes), divided into three groups: „attacking”, „neutral”, „defensive” and the elements „service”, „receiving”. For the set goal and tasks the following methods were applied: the research - study of specialized information sources; method of direct and indirect observation (recording-registration of game activity). The following mathematical-statistical methods were applied: analysis of variance, alternative analysis. The effect of the applied author's methodology on the improvement of attacking style of play, in particular - minimization of unforced errors by the female athletes studied in a pilot study was investigated. The results revealed a decrease in errors made in the „attacking” group from 40% to 32% at the end of the study; in the group of „neutral” strokes the female athletes made approximately the same percentage of errors: 27% and 28% in the second observation. The percentage of recorded inaccuracies for the „defensive” strokes group increased, from 33% in the initial data to 40% in the final measurement. The report reveals in detail the dynamics of the indicator „security” in the technique of the basic strokes in badminton, distributed by groups for the discipline „Women – single”, the results are of practical value for the work of sports educators

Racket orientation angle differences between accurate and inaccurate squash shots, as determined by a racket embedded magnetic-inertial measurement unit

ABSTRACT Ascertaining how racket orientation angle differences at ball-impact influence the accuracy of different squash strokes could assist player skill development and possibly reduce the number of unforced errors hit within a match. The purpose of this study was to identify differences in racket orientation angles of accurate and inaccurate forehand and backhand drive, volley and drop shots. A magnetic-inertial measurement unit embedded in a racket output orientation angles of twelve male junior players, with five accurate and five inaccurate shots per player per stroke analysed. Paired samples t-tests revealed that inaccurate backhand drop shots exhibited significantly (p < 0.05) less racket roll angle (racket face less open) at impact than accurate shots, indicating this parameter was a determining factor in the accuracy of this stroke. Racket orientation angle differences between accurate and inaccurate shots of the remaining strokes were too small to be used to distinguish shot accuracy. There was significantly greater variability in racket orientation angles during inaccurate forehand drop and backhand drive shots compared to accurate shots. These findings demonstrate how racket orientation angle differences at ball-impact can influence the accuracy of shots and highlights the need for consistent racket orientations to allow for an accurate shot.

Effects of a Structured Training Plan in Technical-Tactical Exercises on Unforced Errors in Competition in Table Tennis Athletes

Effects of a Structured Training Plan in Technical-Tactical Exercises on Unforced Errors in Competition in Table Tennis Athletes

Cost of an unforced error in tennis: a statistical approach

The objective of this paper is to (1) introduce a scientific way of measuring the cost of an unforced error in tennis during various match situations and (2) to provide a basis for players and coaches to choose the right strategy among extremely cautious and adventurous playing styles based on a statistical approach. To do this, we analyzed a total of 2,490 different match situations. The results of this study show that the cost of an unforced error varies greatly depending on the match situation. Players are better served by playing a high percentage, low-risk game in situations when the cost of an unforced error is higher than the median cost and adapt a high-risk approach when it is lower than the median cost.

Development and implementation of a mental development programme for young elite tennis players

This study was conducted with two young Canadian elite tennis players. An eight-week practical work was conducted with the aim of acquiring new knowledge in sports psychology, and then applying these notions in several competitive situations. Specifically, we focused on the control of thoughts during the 25-second break between rallies. The players were taught a specific mental routine that they had to perform between each point. In terms of results, there was a very interesting trend after analysing the data collected. When players did not perform their pre-set routine before a rally, they had more than 50% chance of losing the next point by making an unforced error.

Sex differences in professional padel players: analysis across four seasons

ABSTRACT Despite the growth of research on padel, available literature is mainly focused on male samples of modest size. This study characterised the differences in performance between men’s and women’s top-class padel players competing in the World Padel Tour (WPT) across four entire seasons (2016–19). Game performance indications from 1070 sets (532 matches) were collected from the official WPT website records. Men and women’s performance were compared by means of the set result and the season. Men padel players performed a smaller number of actions, winners and errors per game than women, except winning smashes and smashes, by order of effect size (ES) magnitude: winning smashes (ES = 1.27), smashes (ES = 1.26), unforced errors (ES = 0.59), winners (ES = 0.55), breakpoints won (ES = 0.42), breakpoints (ES = 0.41) and winning volleys (ES = 0.24). Additionally, sex differences in unforced errors, winners, breakpoints, and breakpoints won become bigger as the time goes, with men showing an increasing greater performance. These findings confirm the existence of sex differences in professional padel performance and a worrying trend to becoming bigger. The sex specificities should be considered to both optimise training and competition plans and mitigated these sex disparities in padel players.

Game patterns in padel: a sequential analysis of elite men players

ABSTRACT The aims of this study were to identify key game patterns and to determine the sequential relationship between each possible combination to assess the usefulness and effectiveness of certain behaviours in elite men padel players. A total of 3,811 stroke-by-stroke actions were collected from 12 sets from five final games of the professional men’s padel championship World Padel Tour (WPT). A multievent sequential data analysis was conducted to determine the interaction and transition probabilities between game patterns. The findings revealed that high-level padel competition is mostly defined by 10 to 40 game patterns and interactions, thus players should mask their real intentions to increase the opponents’ uncertainty. Because volleys and smashes were equally effective but smashes were more likely to fail by an unforced error, players could refine their offensive strategies by a better domain of volleys to solve the point, while reducing the use of definitive smashes for particular situations. Likewise, the use of aggressive backwall counterattacks in response to smashes seems to be an effective offensive strategy in high-level padel players. These findings contribute to a better knowledge of high-level padel game dynamics while providing coaches and players useful information to optimise the training and decision-making strategies.

Psychological pressure and compounded errors during elite-level tennis

ObjectivesIn the context of Grand Slam tennis, we sought to examine how situational pressure and prior errors can disrupt subsequent performance in elite performers. MethodsA retrospective analysis of more than 650,000 points across 12 Grand Slam tennis tournaments from 2016 to 2019 was conducted to identify pressurised in-game moments and unforced errors. A scoring system was used to index situational pressure based on the current match situation (e.g., break points, stage of the match) on a point-by-point basis. The occurrence of performance errors was identified based on double faults and unforced errors, as instances of controllable mistakes. ResultsA mixed effects logistic regression model revealed that an increase in the pressure index (a 1–5 score) significantly increased the probability of a performance error (ps < .001), as did an error on the preceding point (OR = 1.2, 95%CI [1.17, 1.23], p < .001). A multiplicative effect of pressure and prior errors also emerged, as the negative impact of prior errors on performance was greater when situational pressure was already high, in line with the predictions of Attentional Control Theory: Sport (ACTS). Analyses of the distribution of winners and unforced errors across individual players revealed that winning players were as susceptible to pressure and prior errors as losing players. ConclusionsThese findings extend our understanding of how ongoing feedback from prior mistakes may further exacerbate the effects of pressure on performance.

The Random Walk Presidency

AbstractDonald Trump's erratic and unpredictable behavior as president was, metaphorically at least, a Random Walk. Combined with an inexperienced White House staff and a near total absence of any meaningful decision‐making processes, the result was, routinely, unforced errors that both impeded the president’s ability to see his policy goals implemented effectively, led to poor congressional relations and, in several key cases, failures of leadership that played a role in his defeat in the 2020 election. The worst policy outcome was his catastrophic response to the COVID‐19 pandemic, which laid bare the pathologies of poor decision‐making processes. As president, Trump’s record exposed institutional weaknesses that a more skilled populist or authoritarian successor may be able to exploit.

Hedge fund wants changes at Corteva

Starboard Value, a hedge fund and investor in Corteva Agriscience, is pressing for leadership changes at the firm, which spun out of the merger of Dow and DuPont in 2019. According to Starboard, Corteva has not achieved the cost savings expected from combining Dow and DuPont businesses, and its profit margin lags behind those of competitors such as Bayer and FMC. In a letter to Corteva’s board, Starboard advocates replacing CEO Jim Collins and bringing on eight new board members. “A litany of missed promises and unforced errors have furthered our conviction that current leadership is ill-equipped to maximize the value of Corteva’s assets,” the letter says.

My Life as an Ice Cream Sandwich by I. Zoboi

Zoboi, Ibi. My Life as an Ice Cream Sandwich. Penguin Random House, 2019.&#x0D; My Life as an Ice Cream Sandwich is Ibi Zoboi’s middle-grade debut, following her YA novels Pride and the National Book Award finalist American Street. Some of Zoboi’s concerns in her YA fiction are revisited here: Black community and communities, complexities of family relationships, and the difficulties and joys of discovering new places. Here Zoboi adds to the mix a quirky, sci-fi loving protagonist, and a historical setting: Harlem in the summer of 1984.&#x0D; Ebony-Grace Norfleet Freeman (aka E-Grace Starfleet in her galactic "imagination location," aka Ice Cream Sandwich to the Nine Flavas crew of MCs and B-girls) is a seventh-grader from Huntsville who is sent to live with her father in New York City for the summer. She’s full of science fiction knowledge and enthusiasm, abetted by her Granddaddy, who worked for NASA and occupies a large role in her internal narrative as Captain Fleet.&#x0D; Ebony-Grace is a somewhat frustrating protagonist, making a number of seeming unforced errors due to her commitment to her spacefaring alter ego, but she is authentic and compelling, too. Her insistence on being E-Grace Starfleet can be endearing, though she’s clearly using her imagination to avoid dealing with, or understanding, what’s happening around her. She describes her surroundings in terms of her space adventure: that Captain Fleet has been taken captive by the Sonic King on Planet Boom Box, and that the Sonic Boom threatens to overtake everything. Her new friends initially have little time for this kind of play; they’re busy developing their crew’s double-dutch, rapping and breakdancing skills in preparation for a competition that might get them into the big leagues. The culture-shock contrast, in other words, isn’t just between Huntsville and Harlem, but also between one kind of play and (although the Nine Flavas crew don’t see it like this) another; between childhood and adolescence.&#x0D; A caution for readers who appreciate concreteness: one subplot seems ambiguous to the point of opacity. Ebony-Grace has been sent to New York because of some trouble her Granddaddy has gotten into, or possibly a health crisis he is having. There are allusions from adult characters to sins Ebony-Grace’s grandfather has committed, consequences for bad decisions, lawyers, and journalists. His death near the end of the novel leaves both Ebony-Grace and the reader with questions but little closure; veiled references imply a sex-and-drugs aspect to his troubles, or a connection to the AIDS crisis, but this is never clarified.The narrative here is more atmospheric than propulsive, but that atmosphere is alive with culture and history. Character voices are lively, funny, and down to earth; their moment is depicted lovingly and specifically but without preciousness or nostalgia. This love letter to 1980s New York has mountains of appeal for any reader interested in science fiction or hip hop culture, and is a must for any collection looking to continue prioritizing diversity and representation in its holdings.&#x0D; Highly recommended: 4 out of 4 starsReviewer: Amanda Daignault &#x0D; Amanda Daignault is a PhD Candidate in the Department of English and Film Studies at the University of Alberta. She studies contemporary children's middle-grade fantasy novels, using methods of book history and bibliography to figure out where all those giant trilogies came from and what they're doing.&#x0D;

Effect of a Seeding System on Competitive Performance of Elite Players During Major Tennis Tournaments.

The performance of professional tennis players in the four major Grand Slam tournaments has always been an important research topic, which advances the understanding of the current development of tennis. However, there is little known about the difference between higher-ranked and lower-ranked players considering match performance statistics. The study was aimed to explore the technical, tactical, and physical performance indicators that best discriminate seeded and non-seeded male players in Grand Slams. A total of 549 matches played by 189 individual players during 2015–2017 Grand Slam men’s singles were sampled, with corresponding match statistics gathered for each player observation, concerning players’ serving, returning, net point, break point, efficiency, and physical performance. The results showed that the seeded players outperformed the non-seeded players in serve and return, break point, net point, and efficiency-related indicators, while the following indicators contributed most to the separation of two player categories: serve and return of serve points won (%), ace (%), peak serve speed, net points won (%), break point per return game, break point saved, winner and unforced error ratio, and dominance ratio. The research findings evidenced the decreased competitive balance in men’s competition during Grand Slams due to a rank-based seeding system, whereas coaches could use the information to fine-tune the training benchmarks and match planning.

Who, how and when to perform winner points and unforced errors in badminton matches? An analysis of men’s single matches in the 2016 Olympic Games

ABSTRACT The aim of the present study was to (i) establish the probability of winning a badminton game based on the number of unforced errors (UE) and winner points (WP); (ii) analyse the moment of the game that these actions are performed; (iii) analyse the relationship between the number of UE and WP and the athletes ranking. The sample included all men single matches (n = 57) from the 2016 Olympic Games. Winner players performed significantly more WP, while loser players performed significantly more UE. Moderate correlations were found between single ranking of the players and mean number of WP (r = −0.45, p < 0.01) and UE (r = 0.40, p < 0.01) performed per match. A number greater than 10 WP and less than 5 UE present a high probability (>80%) of winning a game. In the last moments of the first and second games, the loser players perform significantly lower numbers of UE. At the last moments of the first and second games, the winner players perform significantly lower numbers of WP. The study suggests that athletes and coaches might pay attention before the match to the ranking position of the opponent and during the game at the moment that the number of UE becomes greater than PV.

On Seitz’s The Elder Testament: He Pitched a Winning Game but with Unforced Errors

Seitz’s new book is a “ Summa” of his decades-long work of theological exegesis which shows the theological “pressure” that the Old Testament inherently exerts towards the Christian doctrine of the Trinity. His focus is not just the “economic” Trinity—God in God’s historical works—but the “ontological Trinity”: God in God’s very self. His exegesis mines theological insights from the church fathers to the great Reformers, Luther and Calvin. An unfortunate weakness in the book is its copy editing and proofreading.